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言語:

scons (1)

名前

scons - a software construction tool

形式

scons [options...] [name=val...] [targets...]

説明

SCONS(1) SCons 4.2.0 SCONS(1)

NAME
scons - a software construction tool

SYNOPSIS
scons [options...] [name=val...] [targets...]

DESCRIPTION
scons orchestrates the construction of software (and other tangible
products such as documentation files) by determining which component
pieces must be built or rebuilt and invoking the necessary commands to
build them. SCons offers many features to improve developer
productivity such as parallel builds, caching of build artifacts,
automatic dependency scanning, and a database of information about
previous builds so details do not have to be recalculated each run.

scons requires Python 3.5 or later to run; there should be no other
dependencies or requirements.
Support for Python 3.5 is deprecated since SCons 4.2 and will be
dropped in a future release. The CPython project has retired 3.5:
https://www.python.org/dev/peps/pep-0478.

You set up an SCons build system by writing a script that describes
things to build (targets), and, if necessary, the rules to build those
files (actions). SCons comes with a collection of Builder methods
which apply premade actions for building many common software
components such as executable programs, object files and libraries, so
that for many software projects, only the targets and input files
(sources) need be specified in a call to a builder. scons thus can
operate at a level of abstraction above that of pure files. For example
if you specify a library target named "foo", scons keeps track of the
actual operating system dependent filename (such as libfoo.so on a
GNU/Linux system), and how to refer to that library in later
construction steps that want to use it, so you don't have to specify
that precise information yourself. scons can also scan automatically
for dependency information, such as header files included by source
code files, so this does not have to be specified manually.

When invoked, scons looks for a file named SConstruct in the current
directory and reads the build configuration from that file (other names
are allowed, see the section called "SConscript Files" for more
information). The SConstruct file may specify subsidiary configuration
files by calling the SConscript function. By convention, these
subsidiary files are named SConscript, although any name may be used.
As a result of this naming convention, the term SConscript files is
used to refer generically to the complete set of configuration files
for a project (including the SConstruct file), regardless of the actual
file names or number of such files.

Before reading the SConscript files, scons looks for a directory named
site_scons in various system directories and in the directory
containing the SConstruct file or, if specified, the directory from the
--site-dir option instead, and prepends the ones it finds to the Python
module search path (sys.path), thus allowing modules in such
directories to be imported in the normal Python way in SConscript
files. For each found site directory, (1) if it contains a file
site_init.py that file is evaluated, and (2) if it contains a directory
site_tools the path to that directory is prepended to the default
toolpath. See the --site-dir and --no-site-dir options for details on
default paths and controlling the site directories.

SConscript files are written in the Python programming language,
although it is normally not necessary to be a Python programmer to use
scons effectively. SConscript files are invoked in a context that makes
the facilities described in this manual page available in their local
namespace without any special steps. Standard Python scripting
capabilities such as flow control, data manipulation, and imported
Python libraries are available to use to handle complicated build
situations. Other Python files can be made a part of the build system,
but they do not automatically have the SCons context and need to import
it if they need access (described later).

scons reads and executes all of the included SConscript files before it
begins building any targets. To make this clear, scons prints the
following messages about what it is doing:

$ scons foo.out
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
cp foo.in foo.out
scons: done building targets.
$

The status messages (lines beginning with the scons: tag) may be
suppressed using the -Q option.

scons does not automatically propagate the external environment used to
execute scons to the commands used to build target files. This is so
that builds will be guaranteed repeatable regardless of the environment
variables set at the time scons is invoked. This also means that if the
compiler or other commands that you want to use to build your target
files are not in standard system locations, scons will not find them
unless you explicitly include the locations into the execution
environment by setting the path in the ENV construction variable in the
internal construction environment:

import os
env = Environment(ENV={'PATH': os.environ['PATH']})

Similarly, if the commands use specific external environment variables
that scons does not recognize, they can be propagated into the
execution environment:

import os

env = Environment(
ENV={
'PATH': os.environ['PATH'],
'ANDROID_HOME': os.environ['ANDROID_HOME'],
'ANDROID_NDK_HOME': os.environ['ANDROID_NDK_HOME'],
}
)

Or you may explicitly propagate the invoking user's complete external
environment:

import os
env = Environment(ENV=os.environ.copy())

This comes at the expense of making your build dependent on the user's
environment being set correctly, but it may be more convenient for many
configurations. It should not cause problems if done in a build setup
which tightly controls how the environment is set up before invoking
scons, as in many continuous integration setups.

scons can scan known input file types automatically for dependency
information (for example, #include preprocessor directives in C or C++
files) and will rebuild dependent files appropriately whenever any
"included" input file changes. scons supports the ability to define
new scanners to support additional input file types.

scons is normally executed in a top-level directory containing an
SConstruct file. When scons is invoked, the command line (including the
contents of the SCONSFLAGS environment variable, if set) is processed.
Command-line options (see the section called "OPTIONS") are consumed.
Any variable argument assignments are collected, and remaining
arguments are taken as targets to build.

Values of variables to be passed to the SConscript files may be
specified on the command line:

scons debug=1

These variables are available through the ARGUMENTS dictionary, and can
be used in the SConscript files to modify the build in any way:

if ARGUMENTS.get('debug', 0):
env = Environment(CCFLAGS='-g')
else:
env = Environment()

The command-line variable arguments are also available in the ARGLIST
list, indexed by their order on the command line. This allows you to
process them in order rather than by name, if necessary. Each ARGLIST
entry is a tuple containing (argname, argvalue).

See the section called "Command-Line Construction Variables" for more
information.

scons can maintain a cache of target (derived) files that can be shared
between multiple builds. When derived-file caching is enabled in an
SConscript file, any target files built by scons will be copied to the
cache. If an up-to-date target file is found in the cache, it will be
retrieved from the cache instead of being rebuilt locally. Caching
behavior may be disabled and controlled in other ways by the
--cache-force, --cache-disable, --cache-readonly, and --cache-show
command-line options. The --random option is useful to prevent multiple
builds from trying to update the cache simultaneously.

By default, scons searches for known programming tools on various
systems and initializes itself based on what is found. On Windows
systems which identify as win32, scons searches in order for the
Microsoft Visual C++ tools, the MinGW tool chain, the Intel compiler
tools, and the PharLap ETS compiler. On Windows system which identify
as cygwin (that is, if scons is invoked from a cygwin shell), the order
changes to prefer the GCC toolchain over the MSVC tools. On OS/2
systems, scons searches in order for the OS/2 compiler, the GCC tool
chain, and the Microsoft Visual C++ tools, On SGI IRIX, IBM AIX,
Hewlett Packard HP-UX, and Oracle Solaris systems, scons searches for
the native compiler tools (MIPSpro, Visual Age, aCC, and Forte tools
respectively) and the GCC tool chain. On all other platforms, including
POSIX (Linux and UNIX) platforms, scons searches in order for the GCC
tool chain, and the Intel compiler tools. These default values may be
overridden by appropriate setting of construction variables.

Target Selection
SCons acts on the selected targets, whether the requested operation is
build, no-exec or clean. Targets are selected as follows:

1. Targets specified on the command line. These may be files,
directories, or phony targets defined using the Alias function.
Directory targets are scanned by scons for any targets that may be
found with a destination in or under that directory. The targets
listed on the command line are made available in the
COMMAND_LINE_TARGETS list.

2. If no targets are specified on the command line, scons will select
those targets specified in the SConscript files via calls to the
Default function. These are known as the default targets, and are
made available in the DEFAULT_TARGETS list.

3. If no targets are selected by the previous steps, scons selects the
current directory for scanning, unless command-line options which
affect the target scan are detected (-C, -D, -u, -U). Since targets
thus selected were not the result of user instructions, this target
list is not made available for direct inspection; use the
--debug=explain option if they need to be examined.

4. scons always adds to the selected targets any intermediate targets
which are necessary to build the specified ones. For example, if
constructing a shared library or dll from C source files, scons
will also build the object files which will make up the library.

To ignore the default targets specified through calls to Default and
instead build all target files in or below the current directory
specify the current directory (.) as a command-line target:

scons .

To build all target files, including any files outside of the current
directory, supply a command-line target of the root directory (on POSIX
systems):

scons /

or the path name(s) of the volume(s) in which all the targets should be
built (on Windows systems):

scons C:\ D:\

A subset of a hierarchical tree may be built by remaining at the
top-level directory (where the SConstruct file lives) and specifying
the subdirectory as the target to build:

scons src/subdir

or by changing directory and invoking scons with the -u option, which
traverses up the directory hierarchy until it finds the SConstruct
file, and then builds targets relatively to the current subdirectory
(see also the related -D and -U options):

cd src/subdir
scons -u .

In all cases, more files may be built than are requested, as scons
needs to make sure any dependent files are built.

Specifying "cleanup" targets in SConscript files is usually not
necessary. The -c flag removes all selected targets:

scons -c .

to remove all target files in or under the current directory, or:

scons -c build export

to remove target files under build and export.

Additional files or directories to remove can be specified using the
Clean function in the SConscript files. Conversely, targets that would
normally be removed by the -c invocation can be retained by calling the
NoClean function with those targets.

scons supports building multiple targets in parallel via a -j option
that takes, as its argument, the number of simultaneous tasks that may
be spawned:

scons -j 4

builds four targets in parallel, for example.

OPTIONS
In general, scons supports the same command-line options as GNU Make
and many of those supported by cons.

-b
Ignored for compatibility with non-GNU versions of Make

-c, --clean, --remove
Set clean mode. Clean up by removing the selected targets, well as
any files or directories associated with a selected target through
calls to the Clean function. Will not remove any targets which are
marked for preservation through calls to the NoClean function.

While clean mode removes targets rather than building them, work
which is done directly in Python code in SConscript files will
still be carried out. If it is important to avoid some such work
from taking place in clean mode, it should be protected. An
SConscript file can determine which mode is active by querying
GetOption, as in the call if GetOption("clean"):

--cache-debug=file
Write debug information about derived-file caching to the specified
file. If file is a hyphen (-), the debug information is printed to
the standard output. The printed messages describe what
signature-file names are being looked for in, retrieved from, or
written to the derived-file cache specified by CacheDir.

--cache-disable, --no-cache
Disable derived-file caching. scons will neither retrieve files
from the cache nor copy files to the cache. This option can be used
to temporarily disable the cache without modifying the build
scripts.

--cache-force, --cache-populate
When using CacheDir, populate a derived-file cache by copying any
already-existing, up-to-date derived files to the cache, in
addition to files built by this invocation. This is useful to
populate a new cache with all the current derived files, or to add
to the cache any derived files recently built with caching disabled
via the --cache-disable option.

--cache-readonly
Use the derived-file cache, if enabled, to retrieve files, but do
not not update the cache with any files actually built during this
invocation.

--cache-show
When using a derived-file cache show the command that would have
been executed to build the file (or the corresponding *COMSTR
contents if set) even if the file is retrieved from cache. Without
this option, scons shows a cache retrieval message if the file is
fetched from cache. This allows producing consistent output for
build logs, regardless of whether a target file was rebuilt or
retrieved from the cache.

--config=mode
Control how the Configure call should use or generate the results
of configuration tests. mode should be one of the following
choices:

auto
SCons will use its normal dependency mechanisms to decide if a
test must be rebuilt or not. This saves time by not running the
same configuration tests every time you invoke scons, but will
overlook changes in system header files or external commands
(such as compilers) if you don't specify those dependecies
explicitly. This is the default behavior.

force
If this mode is specified, all configuration tests will be
re-run regardless of whether the cached results are out of
date. This can be used to explicitly force the configuration
tests to be updated in response to an otherwise unconfigured
change in a system header file or compiler.

cache
If this mode is specified, no configuration tests will be rerun
and all results will be taken from cache. scons will report an
error if --config=cache is specified and a necessary test does
not have any results in the cache.

-C directory, --directory=directory
Run as if scons was started in directory instead of the current
working directory. That is, change directory before searching for
the SConstruct, Sconstruct, sconstruct, SConstruct.py,
Sconstruct.py or sconstruct.py file or doing anything else. When
multiple -C options are given, each subsequent non-absolute -C
directory is interpreted relative to the preceding one. This option
is similar to using -f directory/SConstruct, but -f does not search
for any of the predefined SConstruct names in the specified
directory. See also options -u, -U and -D to change the SConstruct
search behavior when this option is used.

-D
Works exactly the same way as the -u option except for the way
default targets are handled. When this option is used and no
targets are specified on the command line, all default targets are
built, whether or not they are below the current directory.

--debug=type[,type...]
Debug the build process. type specifies the kind of debugging info
to emit. Multiple types may be specified, separated by commas. The
following types are recognized:

action-timestamps
Prints additional time profiling information. For each command,
shows the absolute start and end times. This may be useful in
debugging parallel builds. Implies the --debug=time option.

Available since scons 3.1.

count
Print how many objects are created of the various classes used
internally by SCons before and after reading the SConscript
files and before and after building targets. This is not
supported when SCons is executed with the Python -O (optimized)
option or when the SCons modules have been compiled with
optimization (that is, when executing from *.pyo files).

duplicate
Print a line for each unlink/relink (or copy) of a variant file
from its source file. Includes debugging info for unlinking
stale variant files, as well as unlinking old targets before
building them.

explain
Print an explanation of why scons is deciding to (re-)build the
targets it selects for building.

findlibs
Instruct the scanner that searches for libraries to print a
message about each potential library name it is searching for,
and about the actual libraries it finds.

includes
Print the include tree after each top-level target is built.
This is generally used to find out what files are included by
the sources of a given derived file:

$ scons --debug=includes foo.o

memoizer
Prints a summary of hits and misses using the Memoizer, an
internal subsystem that counts how often SCons uses cached
values in memory instead of recomputing them each time they're
needed.

memory
Prints how much memory SCons uses before and after reading the
SConscript files and before and after building targets.

objects
Prints a list of the various objects of the various classes
used internally by SCons.

pdb
Re-run scons under the control of the pdb Python debugger.

prepare
Print a line each time any target (internal or external) is
prepared for building. scons prints this for each target it
considers, even if that target is up to date (see also
--debug=explain). This can help debug problems with targets
that aren't being built; it shows whether scons is at least
considering them or not.

presub
Print the raw command line used to build each target before the
construction environment variables are substituted. Also shows
which targets are being built by this command. Output looks
something like this:

$ scons --debug=presub
Building myprog.o with action(s):
$SHCC $SHCFLAGS $SHCCFLAGS $CPPFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES
...

stacktrace
Prints an internal Python stack trace when encountering an
otherwise unexplained error.

time
Prints various time profiling information:

o The time spent executing each individual build command

o The total build time (time SCons ran from beginning to end)

o The total time spent reading and executing SConscript files

o The total time SCons itself spent running (that is, not
counting reading and executing SConscript files)

o The total time spent executing all build commands

o The elapsed wall-clock time spent executing those build
commands

o The time spent processing each file passed to the
SConscript function

(When scons is executed without the -j option, the elapsed
wall-clock time will typically be slightly longer than the
total time spent executing all the build commands, due to the
SCons processing that takes place in between executing each
command. When scons is executed with the -j option, and your
build configuration allows good parallelization, the elapsed
wall-clock time should be significantly smaller than the total
time spent executing all the build commands, since multiple
build commands and intervening SCons processing should take
place in parallel.)

--diskcheck=type
Enable specific checks for whether or not there is a file on disk
where the SCons configuration expects a directory (or vice versa)
when searching for source and include files. type can be an
available diskcheck type or the special tokens all or none. A
comma-separated string can be used to select multiple checks. The
default setting is all.

Current available checks are:

match
to check that files and directories on disk match SCons'
expected configuration.

Disabling some or all of these checks can provide a performance
boost for large configurations, or when the configuration will
check for files and/or directories across networked or shared file
systems, at the slight increased risk of an incorrect build or of
not handling errors gracefully.

--duplicate=ORDER
There are three ways to duplicate files in a build tree: hard
links, soft (symbolic) links and copies. The default policy is to
prefer hard links to soft links to copies. You can specify a
different policy with this option. ORDER must be one of
hard-soft-copy (the default), soft-hard-copy, hard-copy, soft-copy
or copy. SCons will attempt to duplicate files using the
mechanisms in the specified order.

--enable-virtualenv
Import virtualenv-related variables to SCons.

--experimental=feature
Enable experimental features and/or tools. feature can be an
available feature name or the special tokens all or none. A
comma-separated string can be used to select multiple features. The
default setting is none.

Current available features are: ninja.

Caution
No Support offered for any features or tools enabled by this
flag.
Available since scons 4.2.

-f file, --file=file, --makefile=file, --sconstruct=file
Use file as the initial SConscript file. Multiple -f options may be
specified, in which case scons will read all of the specified
files.

-h, --help
Print a local help message for this project, if one is defined in
the SConscript files (see the Help function), plus a line that
refers to the standard SCons help message. If no local help message
is defined, prints the standard SCons help message (as for the -H
option) plus help for any local options defined through AddOption.
Exits after displaying the appropriate message.

Note that use of this option requires SCons to process the
SConscript files, so syntax errors may cause the help message not
to be displayed.

--hash-chunksize=KILOBYTES
Set the block size used when computing content signatures to
KILOBYTES. This value determines the size of the chunks which are
read in at once when computing signature hashes. Files below that
size are fully stored in memory before performing the signature
computation while bigger files are read in block-by-block. A huge
block-size leads to high memory consumption while a very small
block-size slows down the build considerably.

The default value is to use a chunk size of 64 kilobytes, which
should be appropriate for most uses.

Available since scons 4.2.

--hash-format=ALGORITHM
Set the hashing algorithm used by SCons to ALGORITHM. This value
determines the hashing algorithm used in generating content
signatures or CacheDir keys.

The supported list of values are: md5, sha1, and sha256. However,
the Python interpreter used to run SCons must have the
corresponding support available in the hashlib module to use the
specified algorithm.

Specifying this value changes the name of the SConsign database.
For example, --hash-format=sha256 will create a SConsign database
with name .sconsign_sha256.dblite.

If this option is not specified, a hash format of md5 is used, and
the SConsign database is .sconsign.dblite.

Available since scons 4.2.

-H, --help-options
Print the standard help message about SCons command-line options
and exit.

-i, --ignore-errors
Ignore all errors from commands executed to rebuild files.

-I directory, --include-dir=directory
Specifies a directory to search for imported Python modules. If
several -I options are used, the directories are searched in the
order specified.

--ignore-virtualenv
Suppress importing virtualenv-related variables to SCons.

--implicit-cache
Cache implicit dependencies. This causes scons to use the implicit
(scanned) dependencies from the last time it was run instead of
scanning the files for implicit dependencies. This can
significantly speed up SCons, but with the following limitations:

scons will not detect changes to implicit dependency search paths
(e.g. CPPPATH, LIBPATH) that would ordinarily cause different
versions of same-named files to be used.

scons will miss changes in the implicit dependencies in cases where
a new implicit dependency is added earlier in the implicit
dependency search path (e.g. CPPPATH, LIBPATH) than a current
implicit dependency with the same name.

--implicit-deps-changed
Forces SCons to ignore the cached implicit dependencies. This
causes the implicit dependencies to be rescanned and recached. This
implies --implicit-cache.

--implicit-deps-unchanged
Force SCons to ignore changes in the implicit dependencies. This
causes cached implicit dependencies to always be used. This implies
--implicit-cache.

--install-sandbox=sandbox_path
When using the Install builders, prepend sandbox_path to the
installation paths such that all installed files will be placed
under that directory. This option is unavailable if one of Install,
InstallAs or InstallVersionedLib is not used in the SConscript
files.

--interactive
Starts SCons in interactive mode. The SConscript files are read
once and a scons>>> prompt is printed. Targets may now be rebuilt
by typing commands at interactive prompt without having to re-read
the SConscript files and re-initialize the dependency graph from
scratch.

SCons interactive mode supports the following commands:

build [OPTIONS] [TARGETS] ...
Builds the specified TARGETS (and their dependencies) with the
specified SCons command-line OPTIONS. b and scons are synonyms
for build.

The following SCons command-line options affect the build
command:

--cache-debug=FILE
--cache-disable, --no-cache
--cache-force, --cache-populate
--cache-readonly
--cache-show
--debug=TYPE
-i, --ignore-errors
-j N, --jobs=N
-k, --keep-going
-n, --no-exec, --just-print, --dry-run, --recon
-Q
-s, --silent, --quiet
--taskmastertrace=FILE
--tree=OPTIONS

Any other SCons command-line options that are specified do not
cause errors but have no effect on the build command (mainly
because they affect how the SConscript files are read, which
only happens once at the beginning of interactive mode).

clean [OPTIONS] [TARGETS] ...
Cleans the specified TARGETS (and their dependencies) with the
specified OPTIONS. c is a synonym. This command is itself a
synonym for build --clean

exit
Exits SCons interactive mode. You can also exit by terminating
input (Ctrl+D UNIX or Linux systems, (Ctrl+Z on Windows
systems).

help [COMMAND]
Provides a help message about the commands available in SCons
interactive mode. If COMMAND is specified, h and ? are
synonyms.

shell [COMMANDLINE]
Executes the specified COMMANDLINE in a subshell. If no
COMMANDLINE is specified, executes the interactive command
interpreter specified in the SHELL environment variable (on
UNIX and Linux systems) or the COMSPEC environment variable (on
Windows systems). sh and ! are synonyms.

version
Prints SCons version information.

An empty line repeats the last typed command. Command-line editing
can be used if the readline module is available.

$ scons --interactive
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons>>> build -n prog
scons>>> exit

-j N, --jobs=N
Specifies the maximum number of comcurrent jobs (commands) to run.
If there is more than one -j option, the last one is effective.

-k, --keep-going
Continue as much as possible after an error. The target that failed
and those that depend on it will not be remade, but other targets
specified on the command line will still be processed.

-m
Ignored for compatibility with non-GNU versions of Make.

--max-drift=SECONDS
Set the maximum expected drift in the modification time of files to
SECONDS. This value determines how long a file must be unmodified
before its cached content signature will be used instead of
calculating a new content signature (MD5 checksum) of the file's
contents. The default value is 2 days, which means a file must have
a modification time of at least two days ago in order to have its
cached content signature used. A negative value means to never
cache the content signature and to ignore the cached value if there
already is one. A value of 0 means to always use the cached
signature, no matter how old the file is.

--md5-chunksize=KILOBYTES
A deprecated synonym for --hash-chunksize.

Deprecated since scons 4.2.

-n, --no-exec, --just-print, --dry-run, --recon
Set no execute mode. Print the commands that would be executed to
build any out-of-date target files, but do not execute the
commands.

The output is a best effort, as SCons cannot always precisely
determine what would be built. For example, if a file is generated
by a builder action that is later used in the build, that file is
not available to scan for dependencies on an unbuilt tree, or may
contain out of date information in a built tree.

Work which is done directly in Python code in SConscript files, as
opposed to work done by builder actions during the build phase,
will still be carried out. If it is important to avoid some such
work from taking place in no execute mode, it should be protected.
An SConscript file can determine which mode is active by querying
GetOption, as in the call if GetOption("no_exec"):

--no-site-dir
Prevents the automatic addition of the standard site_scons dirs to
sys.path. Also prevents loading the site_scons/site_init.py modules
if they exist, and prevents adding their site_scons/site_tools dirs
to the toolpath.

--package-type=type
The type or types of package to create when using the Package
builder. In the case of multiple types, type should be a
comma-separated string; SCons will try to build for all of those
packages. Note this option is only available if the packaging tool
has been enabled.

--profile=file
Run SCons under the Python profiler and save the results in the
specified file. The results may be analyzed using the Python pstats
module.

-q, --question
Do not run any commands, or print anything. Just return an exit
status that is zero if the specified targets are already up to
date, non-zero otherwise.

-Q
Quiets SCons status messages about reading SConscript files,
building targets and entering directories. Commands that are
executed to rebuild target files are still printed.

--random
Build dependencies in a random order. This is useful when building
multiple trees simultaneously with caching enabled, to prevent
multiple builds from simultaneously trying to build or retrieve the
same target files.

-s, --silent, --quiet
Silent. Do not print commands that are executed to rebuild target
files. Also suppresses SCons status messages.

-S, --no-keep-going, --stop
Ignored for compatibility with GNU Make

--site-dir=dir
Uses the named dir as the site directory rather than the default
site_scons directories. This directory will be prepended to
sys.path, the module dir/site_init.py will be loaded if it exists,
and dir/site_tools will be added to the default toolpath.

The default set of site_scons directories used when --site-dir is
not specified depends on the system platform, as follows.
Directories are examined in the order given, from most generic to
most specific, so the last-executed site_init.py file is the most
specific one (which gives it the chance to override everything
else), and the directories are prepended to the paths, again so the
last directory examined comes first in the resulting path.

Windows:

%ALLUSERSPROFILE/Application Data/scons/site_scons
%USERPROFILE%/Local Settings/Application Data/scons/site_scons
%APPDATA%/scons/site_scons
%HOME%/.scons/site_scons
./site_scons

Mac OS X:

/Library/Application Support/SCons/site_scons
/opt/local/share/scons/site_scons (for MacPorts)
/sw/share/scons/site_scons (for Fink)
$HOME/Library/Application Support/SCons/site_scons
$HOME/.scons/site_scons
./site_scons

Solaris:

/opt/sfw/scons/site_scons
/usr/share/scons/site_scons
$HOME/.scons/site_scons
./site_scons

Linux, HPUX, and other Posix-like systems:

/usr/share/scons/site_scons
$HOME/.scons/site_scons
./site_scons

--stack-size=KILOBYTES
Set the size stack used to run threads to KILOBYTES. This value
determines the stack size of the threads used to run jobs. These
threads execute the actions of the builders for the nodes that are
out-of-date. This option has no effect unless the number of
concurrent build jobs is larger than one (as set by -j N or
--jobs=N on the command line or SetOption in a script).

Using a stack size that is too small may cause stack overflow
errors. This usually shows up as segmentation faults that cause
scons to abort before building anything. Using a stack size that is
too large will cause scons to use more memory than required and may
slow down the entire build process. The default value is to use a
stack size of 256 kilobytes, which should be appropriate for most
uses. You should not need to increase this value unless you
encounter stack overflow errors.

-t, --touch
Ignored for compatibility with GNU Make. (Touching a file to make
it appear up-to-date is unnecessary when using scons.)

--taskmastertrace=file
Prints trace information to the specified file about how the
internal Taskmaster object evaluates and controls the order in
which Nodes are built. A file name of - may be used to specify the
standard output.

--tree=type[,type...]
Prints a tree of the dependencies after each top-level target is
built. This prints out some or all of the tree, in various formats,
depending on the type specified:

all
Print the entire dependency tree after each top-level target is
built. This prints out the complete dependency tree, including
implicit dependencies and ignored dependencies.

derived
Restricts the tree output to only derived (target) files, not
source files.

linedraw
Draw the tree output using Unicode line-drawing characters
instead of plain ASCII text. This option acts as a modifier to
the selected type(s). If specified alone, without any type, it
behaves as if all had been specified.

Available since scons 4.0.

status
Prints status information for each displayed node.

prune
Prunes the tree to avoid repeating dependency information for
nodes that have already been displayed. Any node that has
already been displayed will have its name printed in [square
brackets], as an indication that the dependencies for that node
can be found by searching for the relevant output higher up in
the tree.

Multiple type choices may be specified, separated by commas:

# Prints only derived files, with status information:
scons --tree=derived,status

# Prints all dependencies of target, with status information
# and pruning dependencies of already-visited Nodes:
scons --tree=all,prune,status target

-u, --up, --search-up
Walks up the directory structure until an SConstruct, Sconstruct,
sconstruct, SConstruct.py, Sconstruct.py or sconstruct.py file is
found, and uses that as the top of the directory tree. If no
targets are specified on the command line, only targets at or below
the current directory will be built.

-U
Works exactly the same way as the -u option except for the way
default targets are handled. When this option is used and no
targets are specified on the command line, all default targets that
are defined in the SConscript(s) in the current directory are
built, regardless of what directory the resultant targets end up
in.

-v, --version
Print the scons version, copyright information, list of authors,
and any other relevant information. Then exit.

-w, --print-directory
Print a message containing the working directory before and after
other processing.

--no-print-directory
Turn off -w, even if it was turned on implicitly.

--warn=type, --warn=no-type
Enable or disable (with the no- prefix) warnings. type specifies
the type of warnings to be enabled or disabled:

all
All warnings.

cache-version
Warnings about the derived-file cache directory specified by
CacheDir not using the latest configuration information. These
warnings are enabled by default.

cache-write-error
Warnings about errors trying to write a copy of a built file to
a specified derived-file cache specified by CacheDir. These
warnings are disabled by default.

corrupt-sconsign
Warnings about unfamiliar signature data in .sconsign files.
These warnings are enabled by default.

dependency
Warnings about dependencies. These warnings are disabled by
default.

deprecated
Warnings about use of currently deprecated features. These
warnings are enabled by default. Not all deprecation warnings
can be disabled with the --warn=no-deprecated option as some
deprecated features which are late in the deprecation cycle may
have been designated as mandatory warnings, and these will
still display. Warnings for certain deprecated features may
also be enabled or disabled individually; see below.

duplicate-environment
Warnings about attempts to specify a build of a target with two
different construction environments that use the same action.
These warnings are enabled by default.

fortran-cxx-mix
Warnings about linking Fortran and C++ object files in a single
executable, which can yield unpredictable behavior with some
compilers.

future-deprecated
Warnings about features that will be deprecated in the future.
Such warnings are disabled by default. Enabling future
deprecation warnings is recommended for projects that
redistribute SCons configurations for other users to build, so
that the project can be warned as soon as possible about
to-be-deprecated features that may require changes to the
configuration.

link
Warnings about link steps.

misleading-keywords
Warnings about the use of two commonly misspelled keywords
targets and sources to Builder calls. The correct spelling is
the singular form, even though target and source can themselves
refer to lists of names or nodes.

missing-sconscript
Warnings about missing SConscript files. These warnings are
enabled by default.

no-object-count
Warnings about the --debug=object feature not working when
scons is run with the Python -O option or from optimized Python
(.pyo) modules.

no-parallel-support
Warnings about the version of Python not being able to support
parallel builds when the -j option is used. These warnings are
enabled by default.

python-version
Warnings about running SCons with a deprecated version of
Python. These warnings are enabled by default.

reserved-variable
Warnings about attempts to set the reserved construction
variable names $CHANGED_SOURCES, $CHANGED_TARGETS, $TARGET,
$TARGETS, $SOURCE, $SOURCES, $UNCHANGED_SOURCES or
$UNCHANGED_TARGETS. These warnings are disabled by default.

stack-size
Warnings about requests to set the stack size that could not be
honored. These warnings are enabled by default.

target_not_build
Warnings about a build rule not building the expected targets.
These warnings are disabled by default.

-Y repository, --repository=repository, --srcdir=repository
Search the specified repository for any input and target files not
found in the local directory hierarchy. Multiple -Y options may be
specified, in which case the repositories are searched in the order
specified.

SCONSCRIPT FILE REFERENCE
SConscript Files
The build configuration is described by one or more files, known as
SConscript files. There must be at least one file for a valid build
(scons will quit if it does not find one). scons by default looks for
this file by the name SConstruct in the directory from which you run
scons, though if necessary, also looks for alternative file names
Sconstruct, sconstruct, SConstruct.py, Sconstruct.py and sconstruct.py
in that order. A different file name (which can include a pathname
part) may be specified via the -f option. Except for the SConstruct
file, these files are not searched for automatically; you add
additional configuration files to the build by calling the SConscript
function. This allows parts of the build to be conditionally included
or excluded at run-time depending on how scons is invoked.

Each SConscript file in a build configuration is invoked independently
in a separate context. This provides necessary isolation so that
different parts of the build don't accidentally step on each other. You
have to be explicit about sharing information, by using the Export
function or the exports argument to the SConscript function, as well as
the Return function in a called SConscript file, and comsume shared
information by using the Import function.

The following sections describe the various SCons facilities that can
be used in SConscript files. Quick links:
Construction Environments
Tools
Builder Methods
Methods and Functions to do Things
SConscript Variables
Construction Variables
Configure Contexts
Command-Line Construction Variables
Node Objects

Construction Environments
A Construction Environment is the basic means by which SConscript files
communicate build information to scons. A new construction environment
is created using the Environment function:

env = Environment()

Construction environment attributes called Construction Variables may
be set either by specifying them as keyword arguments when the object
is created or by assigning them a value after the object is created.
These two are nominally equivalent:

env = Environment(FOO='foo')
env['FOO'] = 'foo'

Note that certain settings which affect tool detection are referenced
only during initialization, and so need to be supplied as part of the
call to Environment. For example, setting $MSVC_VERSION selects the
version of Microsoft Visual C++ you wish to use, but setting it after
the construction environment is constructed has no effect.

As a convenience, construction variables may also be set or modified by
the parse_flags keyword argument during object creation, which has the
effect of the env.MergeFlags method being applied to the argument value
after all other processing is completed. This is useful either if the
exact content of the flags is unknown (for example, read from a control
file) or if the flags need to be distributed to a number of
construction variables. env.ParseFlags describes how these arguments
are distributed to construction variables.

env = Environment(parse_flags='-Iinclude -DEBUG -lm')

This example adds 'include' to the CPPPATH construction variable,
'EBUG' to CPPDEFINES, and 'm' to LIBS.

An existing construction environment can be duplicated by calling the
env.Clone method. Without arguments, it will be a copy with the same
settings. Otherwise, env.Clone takes the same arguments as Environment,
and uses the arguments to create a modified copy.

SCons provides a special construction environment called the Default
Environment. The default environment is used only for global functions,
that is, construction activities called without the context of a
regular construction environment. See DefaultEnvironment for more
information.

By default, a new construction environment is initialized with a set of
builder methods and construction variables that are appropriate for the
current platform. The optional platform keyword argument may be used to
specify that the construction environment should be initialized for a
different platform:

env = Environment(platform='cygwin')
env = Environment(platform='os2')
env = Environment(platform='posix')
env = Environment(platform='win32')

Specifying a platform initializes the appropriate construction
variables in the environment to use and generate file names with
prefixes and suffixes appropriate for that platform.

Note that the win32 platform adds the SystemDrive and SystemRoot
variables from the user's external environment to the construction
environment's ENV dictionary. This is so that any executed commands
that use sockets to connect with other systems (such as fetching source
files from external CVS repository specifications like
:pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons) will work on
Windows systems.

The platform argument may be a function or callable object, in which
case the Environment method will call it to update the new construction
environment:

def my_platform(env):
env['VAR'] = 'xyzzy'

env = Environment(platform=my_platform)

The optional tools and toolpath keyword arguments affect the way tools
available to the environment are initialized. See the section called
"Tools" for details.

The optional variables keyword argument allows passing a Variables
object which will be used in the initialization of the construction
environment See the section called "Command-Line Construction
Variables" for details.

Tools
SCons has a large number of predefined tools (more properly, tool
specifications) which are used to help initialize the construction
environment. An scons tool is only responsible for setup. For example,
if the SConscript file declares the need to construct an object file
from a C-language source file by calling the Object builder, then a
tool representing an available C compiler needs to have run first, to
set up the builder and all the construction variables it needs in the
associated construction environment; the tool itself is not called in
the process of the build. Normally this happens invisibly: scons has
per-platform lists of default tools, and it runs through those tools,
calling the ones which are actually applicable, skipping those where
necessary programs are not installed on the build system, or other
preconditions are not met.

A specific set of tools with which to initialize an environment when
creating it may be specified using the optional keyword argument tools,
which takes a list of tool names. This is useful to override the
defaults, to specify non-default built-in tools, and to supply added
tools:

env = Environment(tools=['msvc', 'lex'])

Tools can also be directly called by using the Tool method (see below).

The tools argument overrides the default tool list, it does not add to
it, so be sure to include all the tools you need. For example if you
are building a c/c++ program you must specify a tool for at least a
compiler and a linker, as in tools=['clang', 'link']. The tool name
'default' can be used to retain the default list.

If no tools argument is specified, or if tools includes 'default', then
scons will auto-detect usable tools, using the execution environment
value of PATH (that is, env['ENV']['PATH'] - the external evironment
PATH from os.environ is not used) for looking up any backing programs,
and the platform name in effect to determine the default tools for that
platform. Changing the PATH variable after the construction environment
is constructed will not cause the tools to be re-detected.

Additional tools can be added to a project either by placing them in a
site_tools subdirectory of a site directory, or in a custom location
specified to scons by giving the toolpath keyword argument. toolpath
also takes a list as its value:

env = Environment(tools=['default', 'foo'], toolpath=['tools'])

This looks for a tool specification module foo.py in directory tools
and in the standard locations, as well as using the ordinary default
tools for the platform.

Directories specified via toolpath are prepended to the existing tool
path. The default tool path is any site_tools directories, so tools in
a specified toolpath take priority, followed by tools in a site_tools
directory, followed by built-in tools. For example, adding a tool
specification module gcc.py to the toolpath directory would override
the built-in gcc tool. The tool path is stored in the environment and
will be used by subsequent calls to the Tool method, as well as by
env.Clone.

base = Environment(toolpath=['custom_path'])
derived = base.Clone(tools=['custom_tool'])
derived.CustomBuilder()

A tool specification module must include two functions:

generate(env, **kwargs)
Modifies the environment referenced by env to set up variables so
that the facilities represented by the tool can be executed. It may
use any keyword arguments that the user supplies in kwargs to vary
its initialization.

exists(env)
Return True if the tool can be called in the context of env.
Usually this means looking up one or more known programs using the
PATH from the supplied env, but the tool can make the "exists"
decision in any way it chooses.

Note
At the moment, user-added tools do not automatically have their
exists function called. As a result, it is recommended that the
generate function be defensively coded - that is, do not rely on
any necessary existence checks already having been performed. This
is expected to be a temporary limitation, and the exists function
should still be provided.

The elements of the tools list may also be functions or callable
objects, in which case the Environment method will call those objects
to update the new construction environment (see Tool for more details):

def my_tool(env):
env['XYZZY'] = 'xyzzy'

env = Environment(tools=[my_tool])

The individual elements of the tools list may also themselves be lists
or tuples of the form (toolname, kw_dict). SCons searches for the
toolname specification file as described above, and passes kw_dict,
which must be a dictionary, as keyword arguments to the tool's generate
function. The generate function can use the arguments to modify the
tool's behavior by setting up the environment in different ways or
otherwise changing its initialization.

# in tools/my_tool.py:
def generate(env, **kwargs):
# Sets MY_TOOL to the value of keyword 'arg1' '1' if not supplied
env['MY_TOOL'] = kwargs.get('arg1', '1')

def exists(env):
return True

# in SConstruct:
env = Environment(tools=['default', ('my_tool', {'arg1': 'abc'})],
toolpath=['tools'])

The tool specification (my_tool in the example) can use the PLATFORM
variable from the construction environment it is passed to customize
the tool for different platforms.

Tools can be "nested" - that is, they can be located within a
subdirectory in the toolpath. A nested tool name uses a dot to
represent a directory separator

# namespaced builder
env = Environment(ENV=os.environ.copy(), tools=['SubDir1.SubDir2.SomeTool'])
env.SomeTool(targets, sources)

# Search Paths
# SCons\Tool\SubDir1\SubDir2\SomeTool.py
# SCons\Tool\SubDir1\SubDir2\SomeTool\__init__.py
# .\site_scons\site_tools\SubDir1\SubDir2\SomeTool.py
# .\site_scons\site_tools\SubDir1\SubDir2\SomeTool\__init__.py

SCons supports the following tool specifications out of the box:

386asm
Sets construction variables for the 386ASM assembler for the Phar
Lap ETS embedded operating system.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $CC, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

aixc++
Sets construction variables for the IMB xlc / Visual Age C++
compiler.

Sets: $CXX, $CXXVERSION, $SHCXX, $SHOBJSUFFIX.

aixcc
Sets construction variables for the IBM xlc / Visual Age C
compiler.

Sets: $CC, $CCVERSION, $SHCC.

aixf77
Sets construction variables for the IBM Visual Age f77 Fortran
compiler.

Sets: $F77, $SHF77.

aixlink
Sets construction variables for the IBM Visual Age linker.

Sets: $LINKFLAGS, $SHLIBSUFFIX, $SHLINKFLAGS.

applelink
Sets construction variables for the Apple linker (similar to the
GNU linker).

Sets: $APPLELINK_COMPATIBILITY_VERSION, $APPLELINK_CURRENT_VERSION,
$APPLELINK_NO_COMPATIBILITY_VERSION, $APPLELINK_NO_CURRENT_VERSION,
$FRAMEWORKPATHPREFIX, $LDMODULECOM, $LDMODULEFLAGS,
$LDMODULEPREFIX, $LDMODULESUFFIX, $LINKCOM, $SHLINKCOM,
$SHLINKFLAGS, $_APPLELINK_COMPATIBILITY_VERSION,
$_APPLELINK_CURRENT_VERSION, $_FRAMEWORKPATH, $_FRAMEWORKS.

Uses: $FRAMEWORKSFLAGS.

ar
Sets construction variables for the ar library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX, $RANLIB,
$RANLIBCOM, $RANLIBFLAGS.

as
Sets construction variables for the as assembler.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $CC, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

bcc32
Sets construction variables for the bcc32 compiler.

Sets: $CC, $CCCOM, $CCFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX,
$CPPDEFSUFFIX, $INCPREFIX, $INCSUFFIX, $SHCC, $SHCCCOM, $SHCCFLAGS,
$SHCFLAGS, $SHOBJSUFFIX.

Uses: $_CPPDEFFLAGS, $_CPPINCFLAGS.

cc
Sets construction variables for generic POSIX C compilers.

Sets: $CC, $CCCOM, $CCFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX,
$CPPDEFSUFFIX, $FRAMEWORKPATH, $FRAMEWORKS, $INCPREFIX, $INCSUFFIX,
$SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHOBJSUFFIX.

Uses: $CCCOMSTR, $PLATFORM, $SHCCCOMSTR.

clang
Set construction variables for the Clang C compiler.

Sets: $CC, $CCVERSION, $SHCCFLAGS.

clangxx
Set construction variables for the Clang C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXXFLAGS, $SHOBJSUFFIX,
$STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME.

compilation_db
Sets up CompilationDatabase builder which generates a clang tooling
compatible compilation database.

Sets: $COMPILATIONDB_COMSTR, $COMPILATIONDB_PATH_FILTER,
$COMPILATIONDB_USE_ABSPATH.

cvf
Sets construction variables for the Compaq Visual Fortran compiler.

Sets: $FORTRAN, $FORTRANCOM, $FORTRANMODDIR, $FORTRANMODDIRPREFIX,
$FORTRANMODDIRSUFFIX, $FORTRANPPCOM, $OBJSUFFIX, $SHFORTRANCOM,
$SHFORTRANPPCOM.

Uses: $CPPFLAGS, $FORTRANFLAGS, $SHFORTRANFLAGS, $_CPPDEFFLAGS,
$_FORTRANINCFLAGS, $_FORTRANMODFLAG.

cXX
Sets construction variables for generic POSIX C++ compilers.

Sets: $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM, $CXXFILESUFFIX,
$CXXFLAGS, $INCPREFIX, $INCSUFFIX, $OBJSUFFIX, $SHCXX, $SHCXXCOM,
$SHCXXFLAGS, $SHOBJSUFFIX.

Uses: $CXXCOMSTR, $SHCXXCOMSTR.

cyglink
Set construction variables for cygwin linker/loader.

Sets: $IMPLIBPREFIX, $IMPLIBSUFFIX, $LDMODULEVERSIONFLAGS,
$LINKFLAGS, $RPATHPREFIX, $RPATHSUFFIX, $SHLIBPREFIX, $SHLIBSUFFIX,
$SHLIBVERSIONFLAGS, $SHLINKCOM, $SHLINKFLAGS,
$_LDMODULEVERSIONFLAGS, $_SHLIBVERSIONFLAGS.

default
Sets construction variables for a default list of Tool modules. Use
default in the tools list to retain the original defaults, since
the tools parameter is treated as a literal statement of the tools
to be made available in that construction environment, not an
addition.

The list of tools selected by default is not static, but is
dependent both on the platform and on the software installed on the
platform. Some tools will not initialize if an underlying command
is not found, and some tools are selected from a list of choices on
a first-found basis. The finished tool list can be examined by
inspecting the $TOOLS construction variable in the construction
environment.

On all platforms, the tools from the following list are selected if
their respective conditions are met: filesystem;, wix, lex, yacc,
rpcgen, swig, jar, javac, javah, rmic, dvipdf, dvips, gs, tex,
latex, pdflatex, pdftex, tar, zip, textfile.

On Linux systems, the default tools list selects (first-found): a C
compiler from gcc, intelc, icc, cc; a C++ compiler from g++,
intelc, icc, cXX; an assembler from gas, nasm, masm; a linker from
gnulink, ilink; a Fortran compiler from gfortran, g77, ifort, ifl,
f95, f90, f77; and a static archiver ar. It also selects all found
from the list m4 rpm.

On Windows systems, the default tools list selects (first-found): a
C compiler from msvc, mingw, gcc, intelc, icl, icc, cc, bcc32; a
C++ compiler from msvc, intelc, icc, g++, cXX, bcc32; an assembler
from masm, nasm, gas, 386asm; a linker from mslink, gnulink, ilink,
linkloc, ilink32; a Fortran compiler from gfortran, g77, ifl, cvf,
f95, f90, fortran; and a static archiver from mslib, ar, tlib; It
also selects all found from the list msvs, midl.

On MacOS systems, the default tools list selects (first-found): a C
compiler from gcc, cc; a C++ compiler from g++, cXX; an assembler
as; a linker from applelink, gnulink; a Fortran compiler from
gfortran, f95, f90, g77; and a static archiver ar. It also selects
all found from the list m4, rpm.

Default lists for other platforms can be found by examining the
scons source code (see SCons/Tool/__init__.py).

dmd
Sets construction variables for D language compiler DMD.

Sets: $DC, $DCOM, $DDEBUG, $DDEBUGPREFIX, $DDEBUGSUFFIX,
$DFILESUFFIX, $DFLAGPREFIX, $DFLAGS, $DFLAGSUFFIX, $DINCPREFIX,
$DINCSUFFIX, $DLIB, $DLIBCOM, $DLIBDIRPREFIX, $DLIBDIRSUFFIX,
$DLIBFLAGPREFIX, $DLIBFLAGSUFFIX, $DLIBLINKPREFIX, $DLIBLINKSUFFIX,
$DLINK, $DLINKCOM, $DLINKFLAGPREFIX, $DLINKFLAGS, $DLINKFLAGSUFFIX,
$DPATH, $DRPATHPREFIX, $DRPATHSUFFIX, $DVERPREFIX, $DVERSIONS,
$DVERSUFFIX, $SHDC, $SHDCOM, $SHDLIBVERSIONFLAGS, $SHDLINK,
$SHDLINKCOM, $SHDLINKFLAGS.

docbook
This tool tries to make working with Docbook in SCons a little
easier. It provides several toolchains for creating different
output formats, like HTML or PDF. Contained in the package is a
distribution of the Docbook XSL stylesheets as of version 1.76.1.
As long as you don't specify your own stylesheets for
customization, these official versions are picked as
default...which should reduce the inevitable setup hassles for you.

Implicit dependencies to images and XIncludes are detected
automatically if you meet the HTML requirements. The additional
stylesheet utils/xmldepend.xsl by Paul DuBois is used for this
purpose.

Note, that there is no support for XML catalog resolving offered!
This tool calls the XSLT processors and PDF renderers with the
stylesheets you specified, that's it. The rest lies in your hands
and you still have to know what you're doing when resolving names
via a catalog.

For activating the tool "docbook", you have to add its name to the
Environment constructor, like this

env = Environment(tools=['docbook'])

On its startup, the docbook tool tries to find a required xsltproc
processor, and a PDF renderer, e.g. fop. So make sure that these
are added to your system's environment PATH and can be called
directly without specifying their full path.

For the most basic processing of Docbook to HTML, you need to have
installed

o the Python lxml binding to libxml2, or

o a standalone XSLT processor, currently detected are xsltproc,
saxon, saxon-xslt and xalan.

Rendering to PDF requires you to have one of the applications fop
or xep installed.

Creating a HTML or PDF document is very simple and straightforward.
Say

env = Environment(tools=['docbook'])
env.DocbookHtml('manual.html', 'manual.xml')
env.DocbookPdf('manual.pdf', 'manual.xml')

to get both outputs from your XML source manual.xml. As a shortcut,
you can give the stem of the filenames alone, like this:

env = Environment(tools=['docbook'])
env.DocbookHtml('manual')
env.DocbookPdf('manual')

and get the same result. Target and source lists are also
supported:

env = Environment(tools=['docbook'])
env.DocbookHtml(['manual.html','reference.html'], ['manual.xml','reference.xml'])

or even

env = Environment(tools=['docbook'])
env.DocbookHtml(['manual','reference'])

Important
Whenever you leave out the list of sources, you may not specify
a file extension! The Tool uses the given names as file stems,
and adds the suffixes for target and source files accordingly.
The rules given above are valid for the Builders DocbookHtml,
DocbookPdf, DocbookEpub, DocbookSlidesPdf and DocbookXInclude. For
the DocbookMan transformation you can specify a target name, but
the actual output names are automatically set from the refname
entries in your XML source.

The Builders DocbookHtmlChunked, DocbookHtmlhelp and
DocbookSlidesHtml are special, in that:

1. they create a large set of files, where the exact names and
their number depend on the content of the source file, and

2. the main target is always named index.html, i.e. the output
name for the XSL transformation is not picked up by the
stylesheets.

As a result, there is simply no use in specifying a target HTML
name. So the basic syntax for these builders is always:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual')

If you want to use a specific XSL file, you can set the additional
xsl parameter to your Builder call as follows:

env.DocbookHtml('other.html', 'manual.xml', xsl='html.xsl')

Since this may get tedious if you always use the same local naming
for your customized XSL files, e.g. html.xsl for HTML and pdf.xsl
for PDF output, a set of variables for setting the default XSL name
is provided. These are:

DOCBOOK_DEFAULT_XSL_HTML
DOCBOOK_DEFAULT_XSL_HTMLCHUNKED
DOCBOOK_DEFAULT_XSL_HTMLHELP
DOCBOOK_DEFAULT_XSL_PDF
DOCBOOK_DEFAULT_XSL_EPUB
DOCBOOK_DEFAULT_XSL_MAN
DOCBOOK_DEFAULT_XSL_SLIDESPDF
DOCBOOK_DEFAULT_XSL_SLIDESHTML

and you can set them when constructing your environment:

env = Environment(
tools=['docbook'],
DOCBOOK_DEFAULT_XSL_HTML='html.xsl',
DOCBOOK_DEFAULT_XSL_PDF='pdf.xsl',
)
env.DocbookHtml('manual') # now uses html.xsl

Sets: $DOCBOOK_DEFAULT_XSL_EPUB, $DOCBOOK_DEFAULT_XSL_HTML,
$DOCBOOK_DEFAULT_XSL_HTMLCHUNKED, $DOCBOOK_DEFAULT_XSL_HTMLHELP,
$DOCBOOK_DEFAULT_XSL_MAN, $DOCBOOK_DEFAULT_XSL_PDF,
$DOCBOOK_DEFAULT_XSL_SLIDESHTML, $DOCBOOK_DEFAULT_XSL_SLIDESPDF,
$DOCBOOK_FOP, $DOCBOOK_FOPCOM, $DOCBOOK_FOPFLAGS, $DOCBOOK_XMLLINT,
$DOCBOOK_XMLLINTCOM, $DOCBOOK_XMLLINTFLAGS, $DOCBOOK_XSLTPROC,
$DOCBOOK_XSLTPROCCOM, $DOCBOOK_XSLTPROCFLAGS,
$DOCBOOK_XSLTPROCPARAMS.

Uses: $DOCBOOK_FOPCOMSTR, $DOCBOOK_XMLLINTCOMSTR,
$DOCBOOK_XSLTPROCCOMSTR.

dvi
Attaches the DVI builder to the construction environment.

dvipdf
Sets construction variables for the dvipdf utility.

Sets: $DVIPDF, $DVIPDFCOM, $DVIPDFFLAGS.

Uses: $DVIPDFCOMSTR.

dvips
Sets construction variables for the dvips utility.

Sets: $DVIPS, $DVIPSFLAGS, $PSCOM, $PSPREFIX, $PSSUFFIX.

Uses: $PSCOMSTR.

f03
Set construction variables for generic POSIX Fortran 03 compilers.

Sets: $F03, $F03COM, $F03FLAGS, $F03PPCOM, $SHF03, $SHF03COM,
$SHF03FLAGS, $SHF03PPCOM, $_F03INCFLAGS.

Uses: $F03COMSTR, $F03PPCOMSTR, $SHF03COMSTR, $SHF03PPCOMSTR.

f08
Set construction variables for generic POSIX Fortran 08 compilers.

Sets: $F08, $F08COM, $F08FLAGS, $F08PPCOM, $SHF08, $SHF08COM,
$SHF08FLAGS, $SHF08PPCOM, $_F08INCFLAGS.

Uses: $F08COMSTR, $F08PPCOMSTR, $SHF08COMSTR, $SHF08PPCOMSTR.

f77
Set construction variables for generic POSIX Fortran 77 compilers.

Sets: $F77, $F77COM, $F77FILESUFFIXES, $F77FLAGS, $F77PPCOM,
$F77PPFILESUFFIXES, $FORTRAN, $FORTRANCOM, $FORTRANFLAGS, $SHF77,
$SHF77COM, $SHF77FLAGS, $SHF77PPCOM, $SHFORTRAN, $SHFORTRANCOM,
$SHFORTRANFLAGS, $SHFORTRANPPCOM, $_F77INCFLAGS.

Uses: $F77COMSTR, $F77PPCOMSTR, $FORTRANCOMSTR, $FORTRANPPCOMSTR,
$SHF77COMSTR, $SHF77PPCOMSTR, $SHFORTRANCOMSTR, $SHFORTRANPPCOMSTR.

f90
Set construction variables for generic POSIX Fortran 90 compilers.

Sets: $F90, $F90COM, $F90FLAGS, $F90PPCOM, $SHF90, $SHF90COM,
$SHF90FLAGS, $SHF90PPCOM, $_F90INCFLAGS.

Uses: $F90COMSTR, $F90PPCOMSTR, $SHF90COMSTR, $SHF90PPCOMSTR.

f95
Set construction variables for generic POSIX Fortran 95 compilers.

Sets: $F95, $F95COM, $F95FLAGS, $F95PPCOM, $SHF95, $SHF95COM,
$SHF95FLAGS, $SHF95PPCOM, $_F95INCFLAGS.

Uses: $F95COMSTR, $F95PPCOMSTR, $SHF95COMSTR, $SHF95PPCOMSTR.

fortran
Set construction variables for generic POSIX Fortran compilers.

Sets: $FORTRAN, $FORTRANCOM, $FORTRANFLAGS, $SHFORTRAN,
$SHFORTRANCOM, $SHFORTRANFLAGS, $SHFORTRANPPCOM.

Uses: $FORTRANCOMSTR, $FORTRANPPCOMSTR, $SHFORTRANCOMSTR,
$SHFORTRANPPCOMSTR.

g++
Set construction variables for the g++ C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXXFLAGS, $SHOBJSUFFIX.

g77
Set construction variables for the g77 Fortran compiler. Calls the
f77 Tool module to set variables.

gas
Sets construction variables for the gas assembler. Calls the as
tool.

Sets: $AS.

gcc
Set construction variables for the gcc C compiler.

Sets: $CC, $CCVERSION, $SHCCFLAGS.

gdc
Sets construction variables for the D language compiler GDC.

gettext
This is actually a toolset, which supports internationalization and
localization of software being constructed with SCons. The toolset
loads following tools:

o xgettext - to extract internationalized messages from source
code to POT file(s),

o msginit - may be optionally used to initialize PO files,

o msgmerge - to update PO files, that already contain translated
messages,

o msgfmt - to compile textual PO file to binary installable MO
file.

When you enable gettext, it internally loads all abovementioned
tools, so you're encouraged to see their individual documentation.

Each of the above tools provides its own builder(s) which may be
used to perform particular activities related to software
internationalization. You may be however interested in top-level
Translate builder.

To use gettext tools add 'gettext' tool to your environment:

env = Environment( tools = ['default', 'gettext'] )

gfortran
Sets construction variables for the GNU F95/F2003 GNU compiler.

Sets: $F77, $F90, $F95, $FORTRAN, $SHF77, $SHF77FLAGS, $SHF90,
$SHF90FLAGS, $SHF95, $SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

gnulink
Set construction variables for GNU linker/loader.

Sets: $LDMODULEVERSIONFLAGS, $RPATHPREFIX, $RPATHSUFFIX,
$SHLIBVERSIONFLAGS, $SHLINKFLAGS, $_LDMODULESONAME, $_SHLIBSONAME.

gs
This Tool sets the required construction variables for working with
the Ghostscript software. It also registers an appropriate Action
with the PDF Builder, such that the conversion from PS/EPS to PDF
happens automatically for the TeX/LaTeX toolchain. Finally, it adds
an explicit Gs Builder for Ghostscript to the environment.

Sets: $GS, $GSCOM, $GSFLAGS.

Uses: $GSCOMSTR.

hpc++
Set construction variables for the compilers aCC on HP/UX systems.

hpcc
Set construction variables for aCC compilers on HP/UX systems.
Calls the cXX tool for additional variables.

Sets: $CXX, $CXXVERSION, $SHCXXFLAGS.

hplink
Sets construction variables for the linker on HP/UX systems.

Sets: $LINKFLAGS, $SHLIBSUFFIX, $SHLINKFLAGS.

icc
Sets construction variables for the icc compiler on OS/2 systems.

Sets: $CC, $CCCOM, $CFILESUFFIX, $CPPDEFPREFIX, $CPPDEFSUFFIX,
$CXXCOM, $CXXFILESUFFIX, $INCPREFIX, $INCSUFFIX.

Uses: $CCFLAGS, $CFLAGS, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

icl
Sets construction variables for the Intel C/C++ compiler. Calls the
intelc Tool module to set its variables.

ifl
Sets construction variables for the Intel Fortran compiler.

Sets: $FORTRAN, $FORTRANCOM, $FORTRANPPCOM, $SHFORTRANCOM,
$SHFORTRANPPCOM.

Uses: $CPPFLAGS, $FORTRANFLAGS, $_CPPDEFFLAGS, $_FORTRANINCFLAGS.

ifort
Sets construction variables for newer versions of the Intel Fortran
compiler for Linux.

Sets: $F77, $F90, $F95, $FORTRAN, $SHF77, $SHF77FLAGS, $SHF90,
$SHF90FLAGS, $SHF95, $SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

ilink
Sets construction variables for the ilink linker on OS/2 systems.

Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX,
$LINK, $LINKCOM, $LINKFLAGS.

ilink32
Sets construction variables for the Borland ilink32 linker.

Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX,
$LINK, $LINKCOM, $LINKFLAGS.

install
Sets construction variables for file and directory installation.

Sets: $INSTALL, $INSTALLSTR.

intelc
Sets construction variables for the Intel C/C++ compiler (Linux and
Windows, version 7 and later). Calls the gcc or msvc (on Linux and
Windows, respectively) tool to set underlying variables.

Sets: $AR, $CC, $CXX, $INTEL_C_COMPILER_VERSION, $LINK.

jar
Sets construction variables for the jar utility.

Sets: $JAR, $JARCOM, $JARFLAGS, $JARSUFFIX.

Uses: $JARCOMSTR.

javac
Sets construction variables for the javac compiler.

Sets: $JAVABOOTCLASSPATH, $JAVAC, $JAVACCOM, $JAVACFLAGS,
$JAVACLASSPATH, $JAVACLASSSUFFIX, $JAVAINCLUDES, $JAVASOURCEPATH,
$JAVASUFFIX.

Uses: $JAVACCOMSTR.

javah
Sets construction variables for the javah tool.

Sets: $JAVACLASSSUFFIX, $JAVAH, $JAVAHCOM, $JAVAHFLAGS.

Uses: $JAVACLASSPATH, $JAVAHCOMSTR.

latex
Sets construction variables for the latex utility.

Sets: $LATEX, $LATEXCOM, $LATEXFLAGS.

Uses: $LATEXCOMSTR.

ldc
Sets construction variables for the D language compiler LDC2.

lex
Sets construction variables for the lex lexical analyser.

Sets: $LEX, $LEXCOM, $LEXFLAGS, $LEXUNISTD.

Uses: $LEXCOMSTR.

link
Sets construction variables for generic POSIX linkers. This is a
"smart" linker tool which selects a compiler to complete the
linking based on the types of source files.

Sets: $LDMODULE, $LDMODULECOM, $LDMODULEFLAGS,
$LDMODULENOVERSIONSYMLINKS, $LDMODULEPREFIX, $LDMODULESUFFIX,
$LDMODULEVERSION, $LDMODULEVERSIONFLAGS, $LIBDIRPREFIX,
$LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM,
$LINKFLAGS, $SHLIBSUFFIX, $SHLINK, $SHLINKCOM, $SHLINKFLAGS,
$__LDMODULEVERSIONFLAGS, $__SHLIBVERSIONFLAGS.

Uses: $LDMODULECOMSTR, $LINKCOMSTR, $SHLINKCOMSTR.

linkloc
Sets construction variables for the LinkLoc linker for the Phar Lap
ETS embedded operating system.

Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX,
$LINK, $LINKCOM, $LINKFLAGS, $SHLINK, $SHLINKCOM, $SHLINKFLAGS.

Uses: $LINKCOMSTR, $SHLINKCOMSTR.

m4
Sets construction variables for the m4 macro processor.

Sets: $M4, $M4COM, $M4FLAGS.

Uses: $M4COMSTR.

masm
Sets construction variables for the Microsoft assembler.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $ASCOMSTR, $ASPPCOMSTR, $CPPFLAGS, $_CPPDEFFLAGS,
$_CPPINCFLAGS.

midl
Sets construction variables for the Microsoft IDL compiler.

Sets: $MIDL, $MIDLCOM, $MIDLFLAGS.

Uses: $MIDLCOMSTR.

mingw
Sets construction variables for MinGW (Minimal Gnu on Windows).

Sets: $AS, $CC, $CXX, $LDMODULECOM, $LIBPREFIX, $LIBSUFFIX,
$OBJSUFFIX, $RC, $RCCOM, $RCFLAGS, $RCINCFLAGS, $RCINCPREFIX,
$RCINCSUFFIX, $SHCCFLAGS, $SHCXXFLAGS, $SHLINKCOM, $SHLINKFLAGS,
$SHOBJSUFFIX, $WINDOWSDEFPREFIX, $WINDOWSDEFSUFFIX.

Uses: $RCCOMSTR, $SHLINKCOMSTR.

msgfmt
This scons tool is a part of scons gettext toolset. It provides
scons interface to msgfmt(1) command, which generates binary
message catalog (MO) from a textual translation description (PO).

Sets: $MOSUFFIX, $MSGFMT, $MSGFMTCOM, $MSGFMTCOMSTR, $MSGFMTFLAGS,
$POSUFFIX.

Uses: $LINGUAS_FILE.

msginit
This scons tool is a part of scons gettext toolset. It provides
scons interface to msginit(1) program, which creates new PO file,
initializing the meta information with values from user's
environment (or options).

Sets: $MSGINIT, $MSGINITCOM, $MSGINITCOMSTR, $MSGINITFLAGS,
$POAUTOINIT, $POCREATE_ALIAS, $POSUFFIX, $POTSUFFIX,
$_MSGINITLOCALE.

Uses: $LINGUAS_FILE, $POAUTOINIT, $POTDOMAIN.

msgmerge
This scons tool is a part of scons gettext toolset. It provides
scons interface to msgmerge(1) command, which merges two Uniform
style .po files together.

Sets: $MSGMERGE, $MSGMERGECOM, $MSGMERGECOMSTR, $MSGMERGEFLAGS,
$POSUFFIX, $POTSUFFIX, $POUPDATE_ALIAS.

Uses: $LINGUAS_FILE, $POAUTOINIT, $POTDOMAIN.

mslib
Sets construction variables for the Microsoft mslib library
archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.

Uses: $ARCOMSTR.

mslink
Sets construction variables for the Microsoft linker.

Sets: $LDMODULE, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULEPREFIX,
$LDMODULESUFFIX, $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX,
$LIBLINKSUFFIX, $LINK, $LINKCOM, $LINKFLAGS, $REGSVR, $REGSVRCOM,
$REGSVRFLAGS, $SHLINK, $SHLINKCOM, $SHLINKFLAGS, $WINDOWSDEFPREFIX,
$WINDOWSDEFSUFFIX, $WINDOWSEXPPREFIX, $WINDOWSEXPSUFFIX,
$WINDOWSPROGMANIFESTPREFIX, $WINDOWSPROGMANIFESTSUFFIX,
$WINDOWSSHLIBMANIFESTPREFIX, $WINDOWSSHLIBMANIFESTSUFFIX,
$WINDOWS_INSERT_DEF.

Uses: $LDMODULECOMSTR, $LINKCOMSTR, $REGSVRCOMSTR, $SHLINKCOMSTR.

mssdk
Sets variables for Microsoft Platform SDK and/or Windows SDK. Note
that unlike most other Tool modules, mssdk does not set
construction variables, but sets the environment variables in the
environment SCons uses to execute the Microsoft toolchain:
%INCLUDE%, %LIB%, %LIBPATH% and %PATH%.

Uses: $MSSDK_DIR, $MSSDK_VERSION, $MSVS_VERSION.

msvc
Sets construction variables for the Microsoft Visual C/C++
compiler.

Sets: $BUILDERS, $CC, $CCCOM, $CCFLAGS, $CCPCHFLAGS, $CCPDBFLAGS,
$CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM,
$CXXFILESUFFIX, $CXXFLAGS, $INCPREFIX, $INCSUFFIX, $OBJPREFIX,
$OBJSUFFIX, $PCHCOM, $PCHPDBFLAGS, $RC, $RCCOM, $RCFLAGS, $SHCC,
$SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHCXX, $SHCXXCOM, $SHCXXFLAGS,
$SHOBJPREFIX, $SHOBJSUFFIX.

Uses: $CCCOMSTR, $CXXCOMSTR, $PCH, $PCHSTOP, $PDB, $SHCCCOMSTR,
$SHCXXCOMSTR.

msvs
Sets construction variables for Microsoft Visual Studio.

Sets: $MSVSBUILDCOM, $MSVSCLEANCOM, $MSVSENCODING, $MSVSPROJECTCOM,
$MSVSREBUILDCOM, $MSVSSCONS, $MSVSSCONSCOM, $MSVSSCONSCRIPT,
$MSVSSCONSFLAGS, $MSVSSOLUTIONCOM.

mwcc
Sets construction variables for the Metrowerks CodeWarrior
compiler.

Sets: $CC, $CCCOM, $CFILESUFFIX, $CPPDEFPREFIX, $CPPDEFSUFFIX,
$CXX, $CXXCOM, $CXXFILESUFFIX, $INCPREFIX, $INCSUFFIX,
$MWCW_VERSION, $MWCW_VERSIONS, $SHCC, $SHCCCOM, $SHCCFLAGS,
$SHCFLAGS, $SHCXX, $SHCXXCOM, $SHCXXFLAGS.

Uses: $CCCOMSTR, $CXXCOMSTR, $SHCCCOMSTR, $SHCXXCOMSTR.

mwld
Sets construction variables for the Metrowerks CodeWarrior linker.

Sets: $AR, $ARCOM, $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX,
$LIBLINKSUFFIX, $LINK, $LINKCOM, $SHLINK, $SHLINKCOM, $SHLINKFLAGS.

nasm
Sets construction variables for the nasm Netwide Assembler.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $ASCOMSTR, $ASPPCOMSTR.

ninja
Sets up Ninja builder which generates a ninja build file, and then
optionally runs ninja.

Note
This is an experimental feature.

This functionality is subject to change and/or removal without
deprecation cycle.
Sets: $IMPLICIT_COMMAND_DEPENDENCIES, $NINJA_ALIAS_NAME,
$NINJA_COMPDB_EXPAND, $NINJA_DIR, $NINJA_DISABLE_AUTO_RUN,
$NINJA_ENV_VAR_CACHE, $NINJA_FILE_NAME,
$NINJA_GENERATED_SOURCE_SUFFIXES, $NINJA_MSVC_DEPS_PREFIX,
$NINJA_POOL, $NINJA_REGENERATE_DEPS, $NINJA_SYNTAX,
$_NINJA_REGENERATE_DEPS_FUNC, $__NINJA_NO.

Uses: $AR, $ARCOM, $ARFLAGS, $CC, $CCCOM, $CCFLAGS, $CXX, $CXXCOM,
$ESCAPE, $LINK, $LINKCOM, $PLATFORM, $PRINT_CMD_LINE_FUNC,
$PROGSUFFIX, $RANLIB, $RANLIBCOM, $SHCCCOM, $SHCXXCOM, $SHLINK,
$SHLINKCOM.

packaging
Sets construction variables for the Package Builder. If this tool
is enabled, the --package-type command-line option is also enabled.

pdf
Sets construction variables for the Portable Document Format
builder.

Sets: $PDFPREFIX, $PDFSUFFIX.

pdflatex
Sets construction variables for the pdflatex utility.

Sets: $LATEXRETRIES, $PDFLATEX, $PDFLATEXCOM, $PDFLATEXFLAGS.

Uses: $PDFLATEXCOMSTR.

pdftex
Sets construction variables for the pdftex utility.

Sets: $LATEXRETRIES, $PDFLATEX, $PDFLATEXCOM, $PDFLATEXFLAGS,
$PDFTEX, $PDFTEXCOM, $PDFTEXFLAGS.

Uses: $PDFLATEXCOMSTR, $PDFTEXCOMSTR.

python
Loads the Python source scanner into the invoking environment. When
loaded, the scanner will attempt to find implicit dependencies for
any Python source files in the list of sources provided to an
Action that uses this environment.

Available since scons 4.0..

qt
Sets construction variables for building Qt applications.

Sets: $QTDIR, $QT_AUTOSCAN, $QT_BINPATH, $QT_CPPPATH, $QT_LIB,
$QT_LIBPATH, $QT_MOC, $QT_MOCCXXPREFIX, $QT_MOCCXXSUFFIX,
$QT_MOCFROMCXXCOM, $QT_MOCFROMCXXFLAGS, $QT_MOCFROMHCOM,
$QT_MOCFROMHFLAGS, $QT_MOCHPREFIX, $QT_MOCHSUFFIX, $QT_UIC,
$QT_UICCOM, $QT_UICDECLFLAGS, $QT_UICDECLPREFIX, $QT_UICDECLSUFFIX,
$QT_UICIMPLFLAGS, $QT_UICIMPLPREFIX, $QT_UICIMPLSUFFIX,
$QT_UISUFFIX.

rmic
Sets construction variables for the rmic utility.

Sets: $JAVACLASSSUFFIX, $RMIC, $RMICCOM, $RMICFLAGS.

Uses: $RMICCOMSTR.

rpcgen
Sets construction variables for building with RPCGEN.

Sets: $RPCGEN, $RPCGENCLIENTFLAGS, $RPCGENFLAGS,
$RPCGENHEADERFLAGS, $RPCGENSERVICEFLAGS, $RPCGENXDRFLAGS.

sgiar
Sets construction variables for the SGI library archiver.

Sets: $AR, $ARCOMSTR, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX, $SHLINK,
$SHLINKFLAGS.

Uses: $ARCOMSTR, $SHLINKCOMSTR.

sgic++
Sets construction variables for the SGI C++ compiler.

Sets: $CXX, $CXXFLAGS, $SHCXX, $SHOBJSUFFIX.

sgicc
Sets construction variables for the SGI C compiler.

Sets: $CXX, $SHOBJSUFFIX.

sgilink
Sets construction variables for the SGI linker.

Sets: $LINK, $RPATHPREFIX, $RPATHSUFFIX, $SHLINKFLAGS.

sunar
Sets construction variables for the Sun library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.

Uses: $ARCOMSTR.

sunc++
Sets construction variables for the Sun C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXX, $SHCXXFLAGS, $SHOBJPREFIX,
$SHOBJSUFFIX.

suncc
Sets construction variables for the Sun C compiler.

Sets: $CXX, $SHCCFLAGS, $SHOBJPREFIX, $SHOBJSUFFIX.

sunf77
Set construction variables for the Sun f77 Fortran compiler.

Sets: $F77, $FORTRAN, $SHF77, $SHF77FLAGS, $SHFORTRAN,
$SHFORTRANFLAGS.

sunf90
Set construction variables for the Sun f90 Fortran compiler.

Sets: $F90, $FORTRAN, $SHF90, $SHF90FLAGS, $SHFORTRAN,
$SHFORTRANFLAGS.

sunf95
Set construction variables for the Sun f95 Fortran compiler.

Sets: $F95, $FORTRAN, $SHF95, $SHF95FLAGS, $SHFORTRAN,
$SHFORTRANFLAGS.

sunlink
Sets construction variables for the Sun linker.

Sets: $RPATHPREFIX, $RPATHSUFFIX, $SHLINKFLAGS.

swig
Sets construction variables for the SWIG interface generator.

Sets: $SWIG, $SWIGCFILESUFFIX, $SWIGCOM, $SWIGCXXFILESUFFIX,
$SWIGDIRECTORSUFFIX, $SWIGFLAGS, $SWIGINCPREFIX, $SWIGINCSUFFIX,
$SWIGPATH, $SWIGVERSION, $_SWIGINCFLAGS.

Uses: $SWIGCOMSTR.

tar
Sets construction variables for the tar archiver.

Sets: $TAR, $TARCOM, $TARFLAGS, $TARSUFFIX.

Uses: $TARCOMSTR.

tex
Sets construction variables for the TeX formatter and typesetter.

Sets: $BIBTEX, $BIBTEXCOM, $BIBTEXFLAGS, $LATEX, $LATEXCOM,
$LATEXFLAGS, $MAKEINDEX, $MAKEINDEXCOM, $MAKEINDEXFLAGS, $TEX,
$TEXCOM, $TEXFLAGS.

Uses: $BIBTEXCOMSTR, $LATEXCOMSTR, $MAKEINDEXCOMSTR, $TEXCOMSTR.

textfile
Set construction variables for the Textfile and Substfile builders.

Sets: $LINESEPARATOR, $SUBSTFILEPREFIX, $SUBSTFILESUFFIX,
$TEXTFILEPREFIX, $TEXTFILESUFFIX.

Uses: $SUBST_DICT.

tlib
Sets construction variables for the Borlan tib library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.

Uses: $ARCOMSTR.

xgettext
This scons tool is a part of scons gettext toolset. It provides
scons interface to xgettext(1) program, which extracts
internationalized messages from source code. The tool provides
POTUpdate builder to make PO Template files.

Sets: $POTSUFFIX, $POTUPDATE_ALIAS, $XGETTEXTCOM, $XGETTEXTCOMSTR,
$XGETTEXTFLAGS, $XGETTEXTFROM, $XGETTEXTFROMPREFIX,
$XGETTEXTFROMSUFFIX, $XGETTEXTPATH, $XGETTEXTPATHPREFIX,
$XGETTEXTPATHSUFFIX, $_XGETTEXTDOMAIN, $_XGETTEXTFROMFLAGS,
$_XGETTEXTPATHFLAGS.

Uses: $POTDOMAIN.

yacc
Sets construction variables for the yacc parse generator.

Sets: $YACC, $YACCCOM, $YACCFLAGS, $YACCHFILESUFFIX,
$YACCHXXFILESUFFIX, $YACCVCGFILESUFFIX.

Uses: $YACCCOMSTR.

zip
Sets construction variables for the zip archiver.

Sets: $ZIP, $ZIPCOM, $ZIPCOMPRESSION, $ZIPFLAGS, $ZIPSUFFIX.

Uses: $ZIPCOMSTR.

Builder Methods
You tell scons what to build by calling Builders, functions which take
particular action(s) to produce a particular result type
(conventionally described by the builder name such as Program) when
given source files of a particular type. Calling a builder defines one
or more targets to the build system; whether the targets are actually
built on a given invocation is determined by command-line options,
target selection rules, and whether SCons determines the target(s) are
out of date.

SCons defines a number of builders, and you can also write your own.
Builders are attached to a construction environment as methods, and the
available builder methods are listed as key-value pairs in the BUILDERS
attribute of the construction environment. The available builders can
be displayed like this for debugging purposes:

env = Environment()
print("Builders:", list(env['BUILDERS']))

Builder methods take two required arguments: target and source. Either
can be passed as a scalar or as a list. The target and source arguments
can be specified either as positional arguments, in which case target
comes first, or as keyword arguments, using target= and source=.
Although both arguments are nominally required, if there is a single
source and the target can be inferred the target argument can be
omitted (see below). Builder methods also take a variety of keyword
arguments, described below.

The builder may add other targets beyond those requested if indicated
by an Emitter (see the section called "Builder Objects" and, for
example, $PROGEMITTER for more information).

Because long lists of file names can lead to a lot of quoting, scons
supplies a Split global function and a same-named environment method
that splits a single string into a list, using strings of white-space
characters as the delimiter. (similar to the Python string split
method, but succeeds even if the input isn't a string.)

The following are equivalent examples of calling the Program builder
method:

env.Program('bar', ['bar.c', 'foo.c'])
env.Program('bar', Split('bar.c foo.c'))
env.Program('bar', env.Split('bar.c foo.c'))
env.Program(source=['bar.c', 'foo.c'], target='bar')
env.Program(target='bar', source=Split('bar.c foo.c'))
env.Program(target='bar', source=env.Split('bar.c foo.c'))
env.Program('bar', source='bar.c foo.c'.split())

Python follows the POSIX pathname convention for path strings: if a
string begins with the operating system pathname separator (on Windows
both the slash and backslash separator work, and any leading drive
specifier is ignored for the determination) it is considered an
absolute path, otherwise it is a relative path. If the path string
contains no separator characters, it is searched for as a file in the
current directory. If it contains separator characters, the search
follows down from the starting point, which is the top of the directory
tree for an absolute path and the current directory for a relative
path.

scons recognizes a third way to specify path strings: if the string
begins with the # character it is top-relative - it works like a
relative path but the search follows down from the directory containing
the top-level SConstruct rather than from the current directory. The #
is allowed to be followed by a pathname separator, which is ignored if
found in that position. Top-relative paths only work in places where
scons will interpret the path (see some examples below). To be used in
other contexts the string will need to be converted to a relative or
absolute path first.

target and source can be absolute, relative, or top-relative. Relative
pathnames are searched considering the directory of the SConscript file
currently being processed as the "current directory".

Examples:

# The comments describing the targets that will be built
# assume these calls are in a SConscript file in the
# a subdirectory named "subdir".

# Builds the program "subdir/foo" from "subdir/foo.c":
env.Program('foo', 'foo.c')

# Builds the program "/tmp/bar" from "subdir/bar.c":
env.Program('/tmp/bar', 'bar.c')

# An initial '#' or '#/' are equivalent; the following
# calls build the programs "foo" and "bar" (in the
# top-level SConstruct directory) from "subdir/foo.c" and
# "subdir/bar.c", respectively:
env.Program('#foo', 'foo.c')
env.Program('#/bar', 'bar.c')

# Builds the program "other/foo" (relative to the top-level
# SConstruct directory) from "subdir/foo.c":
env.Program('#other/foo', 'foo.c')

# This will not work, only SCons interfaces understand '#',
# os.path.exists is pure Python:
if os.path.exists('#inc/foo.h'):
env.Append(CPPPATH='#inc')

When the target shares the same base name as the source and only the
suffix varies, and if the builder method has a suffix defined for the
target file type, then the target argument may be omitted completely,
and scons will deduce the target file name from the source file name.
The following examples all build the executable program bar (on POSIX
systems) or bar.exe (on Windows systems) from the bar.c source file:

env.Program(target='bar', source='bar.c')
env.Program('bar', source='bar.c')
env.Program(source='bar.c')
env.Program('bar.c')

As a convenience, a srcdir keyword argument may be specified when
calling a Builder. When specified, all source file strings that are not
absolute paths or top-relative paths will be interpreted relative to
the specified srcdir. The following example will build the build/prog
(or build/prog.exe on Windows) program from the files src/f1.c and
src/f2.c:

env.Program('build/prog', ['f1.c', 'f2.c'], srcdir='src')

Keyword arguments that are not specifically recognized are treated as
construction variable overrides, which replace or add those variables
on a limited basis. These overrides will only be in effect when
building the target of the builder call, and will not affect other
parts of the build. For example, if you want to specify some libraries
needed by just one program:

env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])

or generate a shared library with a non-standard suffix:

env.SharedLibrary(
target='word',
source='word.cpp',
SHLIBSUFFIX='.ocx',
LIBSUFFIXES=['.ocx'],
)

Note that both the $SHLIBSUFFIX and $LIBSUFFIXES variables must be set
if you want scons to search automatically for dependencies on the
non-standard library names; see the descriptions below of these
variables for more information.

The optional parse_flags keyword argument is recognized by builders.
This works similarly to the env.MergeFlags method, where the argument
value is broken into individual settings and merged into the
appropriate construction variables.

env.Program('hello', 'hello.c', parse_flags='-Iinclude -DEBUG -lm')

This example adds 'include' to CPPPATH, 'EBUG' to CPPDEFINES, and 'm'
to LIBS.

Although the builder methods defined by scons are, in fact, methods of
a construction environment object, many may also be called without an
explicit environment:

Program('hello', 'hello.c')
SharedLibrary('word', 'word.cpp')

If called this way, methods will internally use the default environment
that consists of the tools and values that scons has determined are
appropriate for the local system.

Builder methods that can be called without an explicit environment
(indicated in the listing of builders without a leading env.) may be
called from custom Python modules that you import into an SConscript
file by adding the following to the Python module:

from SCons.Script import *

Builder methods return a NodeList, a list-like object whose elements
are Nodes, SCons' internal representation of build targets or sources.
See the section called "File and Directory Nodes" for more information.
The returned NodeList object can be passed to other builder methods as
source(s) or passed to any SCons function or method where a filename
would normally be accepted.

For example, to add a specific preprocessor define when compiling one
specific object file but not the others:

bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR')
env.Program("prog", ['foo.c', bar_obj_list, 'main.c'])

Using a Node as in this example makes for a more portable build by
avoiding having to specify a platform-specific object suffix when
calling the Program builder method.

The NodeList object is also convenient to pass to the Default function,
for the same reason of avoiding a platform-specific name:

tgt = env.Program("prog", ["foo.c", "bar.c", "main.c"])
Default(tgt)

Builder calls will automatically "flatten" lists passed as source and
target, so they are free to contain elements which are themselves
lists, such as bar_obj_list returned by the StaticObject call above. If
you need to manipulate a list of lists returned by builders directly in
Python code, you can either build a new list by hand:

foo = Object('foo.c')
bar = Object('bar.c')
objects = ['begin.o'] + foo + ['middle.o'] + bar + ['end.o']
for obj in objects:
print(str(obj))

Or you can use the Flatten function supplied by scons to create a list
containing just the Nodes, which may be more convenient:

foo = Object('foo.c')
bar = Object('bar.c')
objects = Flatten(['begin.o', foo, 'middle.o', bar, 'end.o'])
for obj in objects:
print(str(obj))

SCons builder calls return a list-like object, not an actual Python
list, so it is not appropriate to use the Python add operator (+ or +=)
to append builder results to a Python list. Because the list and the
object are different types, Python will not update the original list in
place, but will instead create a new NodeList object containing the
concatenation of the list elements and the builder results. This will
cause problems for any other Python variables in your SCons
configuration that still hold on to a reference to the original list.
Instead, use the Python list extend method to make sure the list is
updated in-place. Example:

object_files = []

# Do NOT use += here:
# object_files += Object('bar.c')
#
# It will not update the object_files list in place.
#
# Instead, use the list extend method:
object_files.extend(Object('bar.c'))

The path name for a Node's file may be used by passing the Node to
Python's builtin str function:

bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR')
print("The path to bar_obj is:", str(bar_obj_list[0]))

Note that because the Builder call returns a NodeList, you have to
access the first element in the list, (bar_obj_list[0] in the example)
to get at the Node that actually represents the object file.

Builder calls support a chdir keyword argument that specifies that the
Builder's action(s) should be executed after changing directory. If the
chdir argument is a string or a directory Node, scons will change to
the specified directory. If the chdir is not a string or Node and is
non-zero, then scons will change to the target file's directory.

# scons will change to the "sub" subdirectory
# before executing the "cp" command.
env.Command('sub/dir/foo.out', 'sub/dir/foo.in',
"cp dir/foo.in dir/foo.out",
chdir='sub')

# Because chdir is not a string, scons will change to the
# target's directory ("sub/dir") before executing the
# "cp" command.
env.Command('sub/dir/foo.out', 'sub/dir/foo.in',
"cp foo.in foo.out",
chdir=1)

Note that SCons will not automatically modify its expansion of
construction variables like $TARGET and $SOURCE when using the chdir
keyword argument--that is, the expanded file names will still be
relative to the top-level directory where SConstruct was found, and
consequently incorrect relative to the chdir directory. If you use the
chdir keyword argument, you will typically need to supply a different
command line using expansions like ${TARGET.file} and ${SOURCE.file} to
use just the filename portion of the targets and source.

When trying to handle errors that may occur in a builder method,
consider that the corresponding Action is executed at a different time
than the SConscript file statement calling the builder. It is not
useful to wrap a builder call in a try block, since success in the
builder call is not the same as the builder itself succeeding. If
necessary, a Builder's Action should be coded to exit with a useful
exception message indicating the problem in the SConscript files -
programmatically recovering from build errors is rarely useful.

scons predefines the following builder methods. Depending on the setup
of a particular construction environment and on the type and software
installation status of the underlying system, not all builders may be
available to that construction environment.

CFile(), env.CFile()
Builds a C source file given a lex (.l) or yacc (.y) input file.
The suffix specified by the $CFILESUFFIX construction variable (.c
by default) is automatically added to the target if it is not
already present. Example:

# builds foo.c
env.CFile(target = 'foo.c', source = 'foo.l')
# builds bar.c
env.CFile(target = 'bar', source = 'bar.y')

Command(), env.Command()
The Command "Builder" is actually a function that looks like a
Builder, but takes a required third argument, which is the action
to take to construct the target from the source, used for "one-off"
builds where a full builder is not needed. Thus it does not follow
the builder calling rules described at the start of this section.
See instead the Command function description for the calling syntax
and details.

CompilationDatabase(), env.CompilationDatabase()

CompilationDatabase is a special builder which adds a target to
create a JSON formatted compilation database compatible with clang
tooling (see the LLVM specification[1]). This database is suitable
for consumption by various tools and editors who can use it to
obtain build and dependency information which otherwise would be
internal to SCons. The builder does not require any source files to
be specified, rather it arranges to emit information about all of
the C, C++ and assembler source/output pairs identified in the
build that are not excluded by the optional filter
$COMPILATIONDB_PATH_FILTER. The target is subject to the usual
SCons target selection rules.

If called with no arguments, the builder will default to a target
name of compile_commands.json.

If called with a single positional argument, scons will "deduce"
the target name from that source argument, giving it the same name,
and then ignore the source. This is the usual way to call the
builder if a non-default target name is wanted.

If called with either the target= or source= keyword arguments, the
value of the argument is taken as the target name. If called with
both, the target= value is used and source= is ignored. If called
with multiple sources, the source list will be ignored, since there
is no way to deduce what the intent was; in this case the default
target name will be used.

Note
You must load the compilation_db tool prior to specifying any
part of your build or some source/output files will not show up
in the compilation database.
Available since scons 4.0.

CXXFile(), env.CXXFile()
Builds a C++ source file given a lex (.ll) or yacc (.yy) input
file. The suffix specified by the $CXXFILESUFFIX construction
variable (.cc by default) is automatically added to the target if
it is not already present. Example:

# builds foo.cc
env.CXXFile(target = 'foo.cc', source = 'foo.ll')
# builds bar.cc
env.CXXFile(target = 'bar', source = 'bar.yy')

DocbookEpub(), env.DocbookEpub()
A pseudo-Builder, providing a Docbook toolchain for EPUB output.

env = Environment(tools=['docbook'])
env.DocbookEpub('manual.epub', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookEpub('manual')

DocbookHtml(), env.DocbookHtml()
A pseudo-Builder, providing a Docbook toolchain for HTML output.

env = Environment(tools=['docbook'])
env.DocbookHtml('manual.html', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookHtml('manual')

DocbookHtmlChunked(), env.DocbookHtmlChunked()
A pseudo-Builder providing a Docbook toolchain for chunked HTML
output. It supports the base.dir parameter. The chunkfast.xsl file
(requires "EXSLT") is used as the default stylesheet. Basic syntax:

env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('manual')

where manual.xml is the input file.

If you use the root.filename parameter in your own stylesheets you
have to specify the new target name. This ensures that the
dependencies get correct, especially for the cleanup via "scons
-c":

env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('mymanual.html', 'manual', xsl='htmlchunk.xsl')

Some basic support for the base.dir parameter is provided. You can
add the base_dir keyword to your Builder call, and the given prefix
gets prepended to all the created filenames:

env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('manual', xsl='htmlchunk.xsl', base_dir='output/')

Make sure that you don't forget the trailing slash for the base
folder, else your files get renamed only!

DocbookHtmlhelp(), env.DocbookHtmlhelp()
A pseudo-Builder, providing a Docbook toolchain for HTMLHELP
output. Its basic syntax is:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual')

where manual.xml is the input file.

If you use the root.filename parameter in your own stylesheets you
have to specify the new target name. This ensures that the
dependencies get correct, especially for the cleanup via "scons
-c":

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('mymanual.html', 'manual', xsl='htmlhelp.xsl')

Some basic support for the base.dir parameter is provided. You can
add the base_dir keyword to your Builder call, and the given prefix
gets prepended to all the created filenames:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual', xsl='htmlhelp.xsl', base_dir='output/')

Make sure that you don't forget the trailing slash for the base
folder, else your files get renamed only!

DocbookMan(), env.DocbookMan()
A pseudo-Builder, providing a Docbook toolchain for Man page
output. Its basic syntax is:

env = Environment(tools=['docbook'])
env.DocbookMan('manual')

where manual.xml is the input file. Note, that you can specify a
target name, but the actual output names are automatically set from
the refname entries in your XML source.

DocbookPdf(), env.DocbookPdf()
A pseudo-Builder, providing a Docbook toolchain for PDF output.

env = Environment(tools=['docbook'])
env.DocbookPdf('manual.pdf', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookPdf('manual')

DocbookSlidesHtml(), env.DocbookSlidesHtml()
A pseudo-Builder, providing a Docbook toolchain for HTML slides
output.

env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('manual')

If you use the titlefoil.html parameter in your own stylesheets you
have to give the new target name. This ensures that the
dependencies get correct, especially for the cleanup via "scons
-c":

env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('mymanual.html','manual', xsl='slideshtml.xsl')

Some basic support for the base.dir parameter is provided. You can
add the base_dir keyword to your Builder call, and the given prefix
gets prepended to all the created filenames:

env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('manual', xsl='slideshtml.xsl', base_dir='output/')

Make sure that you don't forget the trailing slash for the base
folder, else your files get renamed only!

DocbookSlidesPdf(), env.DocbookSlidesPdf()
A pseudo-Builder, providing a Docbook toolchain for PDF slides
output.

env = Environment(tools=['docbook'])
env.DocbookSlidesPdf('manual.pdf', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookSlidesPdf('manual')

DocbookXInclude(), env.DocbookXInclude()
A pseudo-Builder, for resolving XIncludes in a separate processing
step.

env = Environment(tools=['docbook'])
env.DocbookXInclude('manual_xincluded.xml', 'manual.xml')

DocbookXslt(), env.DocbookXslt()
A pseudo-Builder, applying a given XSL transformation to the input
file.

env = Environment(tools=['docbook'])
env.DocbookXslt('manual_transformed.xml', 'manual.xml', xsl='transform.xslt')

Note, that this builder requires the xsl parameter to be set.

DVI(), env.DVI()
Builds a .dvi file from a .tex, .ltx or .latex input file. If the
source file suffix is .tex, scons will examine the contents of the
file; if the string \documentclass or \documentstyle is found, the
file is assumed to be a LaTeX file and the target is built by
invoking the $LATEXCOM command line; otherwise, the $TEXCOM command
line is used. If the file is a LaTeX file, the DVI builder method
will also examine the contents of the .aux file and invoke the
$BIBTEX command line if the string bibdata is found, start
$MAKEINDEX to generate an index if a .ind file is found and will
examine the contents .log file and re-run the $LATEXCOM command if
the log file says it is necessary.

The suffix .dvi (hard-coded within TeX itself) is automatically
added to the target if it is not already present. Examples:

# builds from aaa.tex
env.DVI(target = 'aaa.dvi', source = 'aaa.tex')
# builds bbb.dvi
env.DVI(target = 'bbb', source = 'bbb.ltx')
# builds from ccc.latex
env.DVI(target = 'ccc.dvi', source = 'ccc.latex')

Gs(), env.Gs()
A Builder for explicitly calling the gs executable. Depending on
the underlying OS, the different names gs, gsos2 and gswin32c are
tried.

env = Environment(tools=['gs'])
env.Gs(
'cover.jpg',
'scons-scons.pdf',
GSFLAGS='-dNOPAUSE -dBATCH -sDEVICE=jpeg -dFirstPage=1 -dLastPage=1 -q',
)

Install(), env.Install()
Installs one or more source files or directories in the specified
target, which must be a directory. The names of the specified
source files or directories remain the same within the destination
directory. The sources may be given as a string or as a node
returned by a builder.

env.Install(target='/usr/local/bin', source=['foo', 'bar'])

Note that if target paths chosen for the Install builder (and the
related InstallAs and InstallVersionedLib builders) are outside the
project tree, such as in the example above, they may not be
selected for "building" by default, since in the absence of other
instructions scons builds targets that are underneath the top
directory (the directory that contains the SConstruct file, usually
the current directory). Use command line targets or the Default
function in this case.

If the --install-sandbox command line option is given, the target
directory will be prefixed by the directory path specified. This is
useful to test installs without installing to a "live" location in
the system.

See also FindInstalledFiles. For more thoughts on installation, see
the User Guide (particularly the section on Command-Line Targets
and the chapters on Installing Files and on Alias Targets).

InstallAs(), env.InstallAs()
Installs one or more source files or directories to specific names,
allowing changing a file or directory name as part of the
installation. It is an error if the target and source arguments
list different numbers of files or directories.

env.InstallAs(target='/usr/local/bin/foo',
source='foo_debug')
env.InstallAs(target=['../lib/libfoo.a', '../lib/libbar.a'],
source=['libFOO.a', 'libBAR.a'])

See the note under Install.

InstallVersionedLib(), env.InstallVersionedLib()
Installs a versioned shared library. The symlinks appropriate to
the architecture will be generated based on symlinks of the source
library.

env.InstallVersionedLib(target='/usr/local/bin/foo',
source='libxyz.1.5.2.so')

See the note under Install.

Jar(), env.Jar()
Builds a Java archive (.jar) file from the specified list of
sources. Any directories in the source list will be searched for
.class files). Any .java files in the source list will be compiled
to .class files by calling the Java Builder.

If the $JARCHDIR value is set, the jar command will change to the
specified directory using the -C option. If $JARCHDIR is not set
explicitly, SCons will use the top of any subdirectory tree in
which Java .class were built by the Java Builder.

If the contents any of the source files begin with the string
Manifest-Version, the file is assumed to be a manifest and is
passed to the jar command with the m option set.

env.Jar(target = 'foo.jar', source = 'classes')

env.Jar(target = 'bar.jar',
source = ['bar1.java', 'bar2.java'])

Java(), env.Java()
Builds one or more Java class files. The sources may be any
combination of explicit .java files, or directory trees which will
be scanned for .java files.

SCons will parse each source .java file to find the classes
(including inner classes) defined within that file, and from that
figure out the target .class files that will be created. The class
files will be placed underneath the specified target directory.

SCons will also search each Java file for the Java package name,
which it assumes can be found on a line beginning with the string
package in the first column; the resulting .class files will be
placed in a directory reflecting the specified package name. For
example, the file Foo.java defining a single public Foo class and
containing a package name of sub.dir will generate a corresponding
sub/dir/Foo.class class file.

Examples:

env.Java(target = 'classes', source = 'src')
env.Java(target = 'classes', source = ['src1', 'src2'])
env.Java(target = 'classes', source = ['File1.java', 'File2.java'])

Java source files can use the native encoding for the underlying
OS. Since SCons compiles in simple ASCII mode by default, the
compiler will generate warnings about unmappable characters, which
may lead to errors as the file is processed further. In this case,
the user must specify the LANG environment variable to tell the
compiler what encoding is used. For portibility, it's best if the
encoding is hard-coded so that the compile will work if it is done
on a system with a different encoding.

env = Environment()
env['ENV']['LANG'] = 'en_GB.UTF-8'

JavaH(), env.JavaH()
Builds C header and source files for implementing Java native
methods. The target can be either a directory in which the header
files will be written, or a header file name which will contain all
of the definitions. The source can be the names of .class files,
the names of .java files to be compiled into .class files by
calling the Java builder method, or the objects returned from the
Java builder method.

If the construction variable $JAVACLASSDIR is set, either in the
environment or in the call to the JavaH builder method itself, then
the value of the variable will be stripped from the beginning of
any .class file names.

Examples:

# builds java_native.h
classes = env.Java(target="classdir", source="src")
env.JavaH(target="java_native.h", source=classes)

# builds include/package_foo.h and include/package_bar.h
env.JavaH(target="include", source=["package/foo.class", "package/bar.class"])

# builds export/foo.h and export/bar.h
env.JavaH(
target="export",
source=["classes/foo.class", "classes/bar.class"],
JAVACLASSDIR="classes",
)

Library(), env.Library()
A synonym for the StaticLibrary builder method.

LoadableModule(), env.LoadableModule()
On most systems, this is the same as SharedLibrary. On Mac OS X
(Darwin) platforms, this creates a loadable module bundle.

M4(), env.M4()
Builds an output file from an M4 input file. This uses a default
$M4FLAGS value of -E, which considers all warnings to be fatal and
stops on the first warning when using the GNU version of m4.
Example:

env.M4(target = 'foo.c', source = 'foo.c.m4')

Moc(), env.Moc()
Builds an output file from a moc input file. Moc input files are
either header files or cxx files. This builder is only available
after using the tool 'qt'. See the $QTDIR variable for more
information. Example:

env.Moc('foo.h') # generates moc_foo.cc
env.Moc('foo.cpp') # generates foo.moc

MOFiles(), env.MOFiles()
This builder belongs to msgfmt tool. The builder compiles PO files
to MO files.

Example 1. Create pl.mo and en.mo by compiling pl.po and en.po:

# ...
env.MOFiles(['pl', 'en'])

Example 2. Compile files for languages defined in LINGUAS file:

# ...
env.MOFiles(LINGUAS_FILE = 1)

Example 3. Create pl.mo and en.mo by compiling pl.po and en.po plus
files for languages defined in LINGUAS file:

# ...
env.MOFiles(['pl', 'en'], LINGUAS_FILE = 1)

Example 4. Compile files for languages defined in LINGUAS file
(another version):

# ...
env['LINGUAS_FILE'] = 1
env.MOFiles()

MSVSProject(), env.MSVSProject()
Builds a Microsoft Visual Studio project file, and by default
builds a solution file as well.

This builds a Visual Studio project file, based on the version of
Visual Studio that is configured (either the latest installed
version, or the version specified by $MSVS_VERSION in the
Environment constructor). For Visual Studio 6, it will generate a
.dsp file. For Visual Studio 7, 8, and 9, it will generate a
.vcproj file. For Visual Studio 10 and later, it will generate a
.vcxproj file.

By default, this also generates a solution file for the specified
project, a .dsw file for Visual Studio 6 or a .sln file for Visual
Studio 7 and later. This behavior may be disabled by specifying
auto_build_solution=0 when you call MSVSProject, in which case you
presumably want to build the solution file(s) by calling the
MSVSSolution Builder (see below).

The MSVSProject builder takes several lists of filenames to be
placed into the project file. These are currently limited to srcs,
incs, localincs, resources, and misc. These are pretty
self-explanatory, but it should be noted that these lists are added
to the $SOURCES construction variable as strings, NOT as SCons File
Nodes. This is because they represent file names to be added to the
project file, not the source files used to build the project file.

The above filename lists are all optional, although at least one
must be specified for the resulting project file to be non-empty.

In addition to the above lists of values, the following values may
be specified:

target
The name of the target .dsp or .vcproj file. The correct suffix
for the version of Visual Studio must be used, but the
$MSVSPROJECTSUFFIX construction variable will be defined to the
correct value (see example below).

variant
The name of this particular variant. For Visual Studio 7
projects, this can also be a list of variant names. These are
typically things like "Debug" or "Release", but really can be
anything you want. For Visual Studio 7 projects, they may also
specify a target platform separated from the variant name by a
| (vertical pipe) character: Debug|Xbox. The default target
platform is Win32. Multiple calls to MSVSProject with different
variants are allowed; all variants will be added to the project
file with their appropriate build targets and sources.

cmdargs
Additional command line arguments for the different variants.
The number of cmdargs entries must match the number of variant
entries, or be empty (not specified). If you give only one, it
will automatically be propagated to all variants.

cppdefines
Preprocessor definitions for the different variants. The number
of cppdefines entries must match the number of variant entries,
or be empty (not specified). If you give only one, it will
automatically be propagated to all variants. If you don't give
this parameter, SCons will use the invoking environment's
CPPDEFINES entry for all variants.

cppflags
Compiler flags for the different variants. If a /std:c++ flag
is found then /Zc:__cplusplus is appended to the flags if not
already found, this ensures that intellisense uses the /std:c++
switch. The number of cppflags entries must match the number of
variant entries, or be empty (not specified). If you give only
one, it will automatically be propagated to all variants. If
you don't give this parameter, SCons will combine the invoking
environment's CCFLAGS, CXXFLAGS, CPPFLAGS entries for all
variants.

cpppaths
Compiler include paths for the different variants. The number
of cpppaths entries must match the number of variant entries,
or be empty (not specified). If you give only one, it will
automatically be propagated to all variants. If you don't give
this parameter, SCons will use the invoking environment's
CPPPATH entry for all variants.

buildtarget
An optional string, node, or list of strings or nodes (one per
build variant), to tell the Visual Studio debugger what output
target to use in what build variant. The number of buildtarget
entries must match the number of variant entries.

runfile
The name of the file that Visual Studio 7 and later will run
and debug. This appears as the value of the Output field in the
resulting Visual Studio project file. If this is not specified,
the default is the same as the specified buildtarget value.

Note that because SCons always executes its build commands from the
directory in which the SConstruct file is located, if you generate
a project file in a different directory than the SConstruct
directory, users will not be able to double-click on the file name
in compilation error messages displayed in the Visual Studio
console output window. This can be remedied by adding the Visual
C/C++ /FC compiler option to the $CCFLAGS variable so that the
compiler will print the full path name of any files that cause
compilation errors.

Example usage:

barsrcs = ['bar.cpp']
barincs = ['bar.h']
barlocalincs = ['StdAfx.h']
barresources = ['bar.rc','resource.h']
barmisc = ['bar_readme.txt']

dll = env.SharedLibrary(target='bar.dll',
source=barsrcs)
buildtarget = [s for s in dll if str(s).endswith('dll')]
env.MSVSProject(target='Bar' + env['MSVSPROJECTSUFFIX'],
srcs=barsrcs,
incs=barincs,
localincs=barlocalincs,
resources=barresources,
misc=barmisc,
buildtarget=buildtarget,
variant='Release')

Starting with version 2.4 of SCons it is also possible to specify
the optional argument DebugSettings, which creates files for
debugging under Visual Studio:

DebugSettings
A dictionary of debug settings that get written to the
.vcproj.user or the .vcxproj.user file, depending on the
version installed. As it is done for cmdargs (see above), you
can specify a DebugSettings dictionary per variant. If you give
only one, it will be propagated to all variants.

Currently, only Visual Studio v9.0 and Visual Studio version v11
are implemented, for other versions no file is generated. To
generate the user file, you just need to add a DebugSettings
dictionary to the environment with the right parameters for your
MSVS version. If the dictionary is empty, or does not contain any
good value, no file will be generated.

Following is a more contrived example, involving the setup of a
project for variants and DebugSettings:

# Assuming you store your defaults in a file
vars = Variables('variables.py')
msvcver = vars.args.get('vc', '9')

# Check command args to force one Microsoft Visual Studio version
if msvcver == '9' or msvcver == '11':
env = Environment(MSVC_VERSION=msvcver+'.0', MSVC_BATCH=False)
else:
env = Environment()

AddOption('--userfile', action='store_true', dest='userfile', default=False,
help="Create Visual Studio Project user file")

#
# 1. Configure your Debug Setting dictionary with options you want in the list
# of allowed options, for instance if you want to create a user file to launch
# a specific application for testing your dll with Microsoft Visual Studio 2008 (v9):
#
V9DebugSettings = {
'Command':'c:\\myapp\\using\\thisdll.exe',
'WorkingDirectory': 'c:\\myapp\\using\\',
'CommandArguments': '-p password',
# 'Attach':'false',
# 'DebuggerType':'3',
# 'Remote':'1',
# 'RemoteMachine': None,
# 'RemoteCommand': None,
# 'HttpUrl': None,
# 'PDBPath': None,
# 'SQLDebugging': None,
# 'Environment': '',
# 'EnvironmentMerge':'true',
# 'DebuggerFlavor': None,
# 'MPIRunCommand': None,
# 'MPIRunArguments': None,
# 'MPIRunWorkingDirectory': None,
# 'ApplicationCommand': None,
# 'ApplicationArguments': None,
# 'ShimCommand': None,
# 'MPIAcceptMode': None,
# 'MPIAcceptFilter': None,
}

#
# 2. Because there are a lot of different options depending on the Microsoft
# Visual Studio version, if you use more than one version you have to
# define a dictionary per version, for instance if you want to create a user
# file to launch a specific application for testing your dll with Microsoft
# Visual Studio 2012 (v11):
#
V10DebugSettings = {
'LocalDebuggerCommand': 'c:\\myapp\\using\\thisdll.exe',
'LocalDebuggerWorkingDirectory': 'c:\\myapp\\using\\',
'LocalDebuggerCommandArguments': '-p password',
# 'LocalDebuggerEnvironment': None,
# 'DebuggerFlavor': 'WindowsLocalDebugger',
# 'LocalDebuggerAttach': None,
# 'LocalDebuggerDebuggerType': None,
# 'LocalDebuggerMergeEnvironment': None,
# 'LocalDebuggerSQLDebugging': None,
# 'RemoteDebuggerCommand': None,
# 'RemoteDebuggerCommandArguments': None,
# 'RemoteDebuggerWorkingDirectory': None,
# 'RemoteDebuggerServerName': None,
# 'RemoteDebuggerConnection': None,
# 'RemoteDebuggerDebuggerType': None,
# 'RemoteDebuggerAttach': None,
# 'RemoteDebuggerSQLDebugging': None,
# 'DeploymentDirectory': None,
# 'AdditionalFiles': None,
# 'RemoteDebuggerDeployDebugCppRuntime': None,
# 'WebBrowserDebuggerHttpUrl': None,
# 'WebBrowserDebuggerDebuggerType': None,
# 'WebServiceDebuggerHttpUrl': None,
# 'WebServiceDebuggerDebuggerType': None,
# 'WebServiceDebuggerSQLDebugging': None,
}

#
# 3. Select the dictionary you want depending on the version of visual Studio
# Files you want to generate.
#
if not env.GetOption('userfile'):
dbgSettings = None
elif env.get('MSVC_VERSION', None) == '9.0':
dbgSettings = V9DebugSettings
elif env.get('MSVC_VERSION', None) == '11.0':
dbgSettings = V10DebugSettings
else:
dbgSettings = None

#
# 4. Add the dictionary to the DebugSettings keyword.
#
barsrcs = ['bar.cpp', 'dllmain.cpp', 'stdafx.cpp']
barincs = ['targetver.h']
barlocalincs = ['StdAfx.h']
barresources = ['bar.rc','resource.h']
barmisc = ['ReadMe.txt']

dll = env.SharedLibrary(target='bar.dll',
source=barsrcs)

env.MSVSProject(target='Bar' + env['MSVSPROJECTSUFFIX'],
srcs=barsrcs,
incs=barincs,
localincs=barlocalincs,
resources=barresources,
misc=barmisc,
buildtarget=[dll[0]] * 2,
variant=('Debug|Win32', 'Release|Win32'),
cmdargs='vc=%s' % msvcver,
DebugSettings=(dbgSettings, {}))

MSVSSolution(), env.MSVSSolution()
Builds a Microsoft Visual Studio solution file.

This builds a Visual Studio solution file, based on the version of
Visual Studio that is configured (either the latest installed
version, or the version specified by $MSVS_VERSION in the
construction environment). For Visual Studio 6, it will generate a
.dsw file. For Visual Studio 7 (.NET), it will generate a .sln
file.

The following values must be specified:

target
The name of the target .dsw or .sln file. The correct suffix
for the version of Visual Studio must be used, but the value
$MSVSSOLUTIONSUFFIX will be defined to the correct value (see
example below).

variant
The name of this particular variant, or a list of variant names
(the latter is only supported for MSVS 7 solutions). These are
typically things like "Debug" or "Release", but really can be
anything you want. For MSVS 7 they may also specify target
platform, like this "Debug|Xbox". Default platform is Win32.

projects
A list of project file names, or Project nodes returned by
calls to the MSVSProject Builder, to be placed into the
solution file. It should be noted that these file names are NOT
added to the $SOURCES environment variable in form of files,
but rather as strings. This is because they represent file
names to be added to the solution file, not the source files
used to build the solution file.

Example Usage:

env.MSVSSolution(
target="Bar" + env["MSVSSOLUTIONSUFFIX"],
projects=["bar" + env["MSVSPROJECTSUFFIX"]],
variant="Release",
)

Ninja(), env.Ninja()

Ninja is a special builder which adds a target to create a ninja
build file. The builder does not require any source files to be
specified.

Note
This is an experimental feature. To enable it you must use one
of the following methods

# On the command line
--experimental=ninja

# Or in your SConstruct
SetOption('experimental', 'ninja')

This functionality is subject to change and/or removal without
deprecation cycle.

To use this tool you must install pypi's ninja package[2]. This
can be done via pip install ninja
If called with no arguments, the builder will default to a target
name of ninja.build.

Available since scons 4.2.

Object(), env.Object()
A synonym for the StaticObject builder method.

Package(), env.Package()
Builds software distribution packages. A package is a container
format which includes files to install along with metadata.
Packaging is optional, and must be enabled by specifying the
packaging tool. For example:

env = Environment(tools=['default', 'packaging'])

SCons can build packages in a number of well known packaging
formats. The target package type may be selected with the the
$PACKAGETYPE construction variable or the --package-type command
line option. The package type may be a list, in which case SCons
will attempt to build packages for each type in the list. Example:

env.Package(PACKAGETYPE=['src_zip', 'src_targz'], ...other args...)

The currently supported packagers are:

The metadata comes partly from attributes of the files to be
packaged, and partly from packaging tags. Tags can be passed as
keyword arguments to the Package builder call, and may also be
attached to files (or more accurately, Nodes representing files)
with the Tag function. Some package-level tags are mandatory, and
will lead to errors if omitted. The mandatory tags vary depending
on the package type.

While packaging, the builder uses a temporary location named by the
value of the $PACKAGEROOT variable - the package sources are copied
there before packaging.

Packaging example:

env = Environment(tools=["default", "packaging"])
env.Install("/bin/", "my_program")
env.Package(
NAME="foo",
VERSION="1.2.3",
PACKAGEVERSION=0,
PACKAGETYPE="rpm",
LICENSE="gpl",
SUMMARY="balalalalal",
DESCRIPTION="this should be really really long",
X_RPM_GROUP="Application/fu",
SOURCE_URL="https://foo.org/foo-1.2.3.tar.gz",
)

In this example, the target /bin/my_program created by the Install
call would not be built by default since it is not under the
project top directory. However, since no source is specified to the
Package builder, it is selected for packaging by the default
sources rule. Since packaging is done using $PACKAGEROOT, no write
is actually done to the system's /bin directory, and the target
will be selected since after rebasing to underneath $PACKAGEROOT it
is now under the top directory of the project.

PCH(), env.PCH()
Builds a Microsoft Visual C++ precompiled header. Calling this
builder returns a list of two targets: the PCH as the first
element, and the object file as the second element. Normally the
object file is ignored. This builder is only provided when
Microsoft Visual C++ is being used as the compiler. The PCH builder
is generally used in conjunction with the $PCH construction
variable to force object files to use the precompiled header:

env['PCH'] = env.PCH('StdAfx.cpp')[0]

PDF(), env.PDF()
Builds a .pdf file from a .dvi input file (or, by extension, a
.tex, .ltx, or .latex input file). The suffix specified by the
$PDFSUFFIX construction variable (.pdf by default) is added
automatically to the target if it is not already present. Example:

# builds from aaa.tex
env.PDF(target = 'aaa.pdf', source = 'aaa.tex')
# builds bbb.pdf from bbb.dvi
env.PDF(target = 'bbb', source = 'bbb.dvi')

POInit(), env.POInit()
This builder belongs to msginit tool. The builder initializes
missing PO file(s) if $POAUTOINIT is set. If $POAUTOINIT is not set
(default), POInit prints instruction for user (that is supposed to
be a translator), telling how the PO file should be initialized. In
normal projects you should not use POInit and use POUpdate instead.
POUpdate chooses intelligently between msgmerge(1) and msginit(1).
POInit always uses msginit(1) and should be regarded as builder for
special purposes or for temporary use (e.g. for quick, one time
initialization of a bunch of PO files) or for tests.

Target nodes defined through POInit are not built by default
(they're Ignored from '.' node) but are added to special Alias
('po-create' by default). The alias name may be changed through the
$POCREATE_ALIAS construction variable. All PO files defined through
POInit may be easily initialized by scons po-create.

Example 1. Initialize en.po and pl.po from messages.pot:

# ...
env.POInit(['en', 'pl']) # messages.pot --> [en.po, pl.po]

Example 2. Initialize en.po and pl.po from foo.pot:

# ...
env.POInit(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.po]

Example 3. Initialize en.po and pl.po from foo.pot but using
$POTDOMAIN construction variable:

# ...
env.POInit(['en', 'pl'], POTDOMAIN='foo') # foo.pot --> [en.po, pl.po]

Example 4. Initialize PO files for languages defined in LINGUAS
file. The files will be initialized from template messages.pot:

# ...
env.POInit(LINGUAS_FILE = 1) # needs 'LINGUAS' file

Example 5. Initialize en.po and pl.pl PO files plus files for
languages defined in LINGUAS file. The files will be initialized
from template messages.pot:

# ...
env.POInit(['en', 'pl'], LINGUAS_FILE = 1)

Example 6. You may preconfigure your environment first, and then
initialize PO files:

# ...
env['POAUTOINIT'] = 1
env['LINGUAS_FILE'] = 1
env['POTDOMAIN'] = 'foo'
env.POInit()

which has same efect as:

# ...
env.POInit(POAUTOINIT = 1, LINGUAS_FILE = 1, POTDOMAIN = 'foo')

PostScript(), env.PostScript()
Builds a .ps file from a .dvi input file (or, by extension, a .tex,
.ltx, or .latex input file). The suffix specified by the $PSSUFFIX
construction variable (.ps by default) is added automatically to
the target if it is not already present. Example:

# builds from aaa.tex
env.PostScript(target = 'aaa.ps', source = 'aaa.tex')
# builds bbb.ps from bbb.dvi
env.PostScript(target = 'bbb', source = 'bbb.dvi')

POTUpdate(), env.POTUpdate()
The builder belongs to xgettext tool. The builder updates target
POT file if exists or creates one if it doesn't. The node is not
built by default (i.e. it is Ignored from '.'), but only on demand
(i.e. when given POT file is required or when special alias is
invoked). This builder adds its targe node (messages.pot, say) to a
special alias (pot-update by default, see $POTUPDATE_ALIAS) so you
can update/create them easily with scons pot-update. The file is
not written until there is no real change in internationalized
messages (or in comments that enter POT file).

Note
You may see xgettext(1) being invoked by the xgettext tool even
if there is no real change in internationalized messages (so
the POT file is not being updated). This happens every time a
source file has changed. In such case we invoke xgettext(1) and
compare its output with the content of POT file to decide
whether the file should be updated or not.

Example 1. Let's create po/ directory and place following
SConstruct script there:

# SConstruct in 'po/' subdir
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(['foo'], ['../a.cpp', '../b.cpp'])
env.POTUpdate(['bar'], ['../c.cpp', '../d.cpp'])

Then invoke scons few times:

user@host:$ scons # Does not create foo.pot nor bar.pot
user@host:$ scons foo.pot # Updates or creates foo.pot
user@host:$ scons pot-update # Updates or creates foo.pot and bar.pot
user@host:$ scons -c # Does not clean foo.pot nor bar.pot.

the results shall be as the comments above say.

Example 2. The POTUpdate builder may be used with no target
specified, in which case default target messages.pot will be used.
The default target may also be overridden by setting $POTDOMAIN
construction variable or providing it as an override to POTUpdate
builder:

# SConstruct script
env = Environment( tools = ['default', 'xgettext'] )
env['POTDOMAIN'] = "foo"
env.POTUpdate(source = ["a.cpp", "b.cpp"]) # Creates foo.pot ...
env.POTUpdate(POTDOMAIN = "bar", source = ["c.cpp", "d.cpp"]) # and bar.pot

Example 3. The sources may be specified within separate file, for
example POTFILES.in:

# POTFILES.in in 'po/' subdirectory
../a.cpp
../b.cpp
# end of file

The name of the file (POTFILES.in) containing the list of sources
is provided via $XGETTEXTFROM:

# SConstruct file in 'po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in')

Example 4. You may use $XGETTEXTPATH to define source search path.
Assume, for example, that you have files a.cpp, b.cpp,
po/SConstruct, po/POTFILES.in. Then your POT-related files could
look as below:

# POTFILES.in in 'po/' subdirectory
a.cpp
b.cpp
# end of file

# SConstruct file in 'po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH='../')

Example 5. Multiple search directories may be defined within a
list, i.e. XGETTEXTPATH = ['dir1', 'dir2', ...]. The order in the
list determines the search order of source files. The path to the
first file found is used.

Let's create 0/1/po/SConstruct script:

# SConstruct file in '0/1/po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../', '../../'])

and 0/1/po/POTFILES.in:

# POTFILES.in in '0/1/po/' subdirectory
a.cpp
# end of file

Write two *.cpp files, the first one is 0/a.cpp:

/* 0/a.cpp */
gettext("Hello from ../../a.cpp")

and the second is 0/1/a.cpp:

/* 0/1/a.cpp */
gettext("Hello from ../a.cpp")

then run scons. You'll obtain 0/1/po/messages.pot with the message
"Hello from ../a.cpp". When you reverse order in $XGETTEXTFOM, i.e.
when you write SConscript as

# SConstruct file in '0/1/po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../../', '../'])

then the messages.pot will contain msgid "Hello from ../../a.cpp"
line and not msgid "Hello from ../a.cpp".

POUpdate(), env.POUpdate()
The builder belongs to msgmerge tool. The builder updates PO files
with msgmerge(1), or initializes missing PO files as described in
documentation of msginit tool and POInit builder (see also
$POAUTOINIT). Note, that POUpdate does not add its targets to
po-create alias as POInit does.

Target nodes defined through POUpdate are not built by default
(they're Ignored from '.' node). Instead, they are added
automatically to special Alias ('po-update' by default). The alias
name may be changed through the $POUPDATE_ALIAS construction
variable. You can easily update PO files in your project by scons
po-update.

Example 1. Update en.po and pl.po from messages.pot template (see
also $POTDOMAIN), assuming that the later one exists or there is
rule to build it (see POTUpdate):

# ...
env.POUpdate(['en','pl']) # messages.pot --> [en.po, pl.po]

Example 2. Update en.po and pl.po from foo.pot template:

# ...
env.POUpdate(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.pl]

Example 3. Update en.po and pl.po from foo.pot (another version):

# ...
env.POUpdate(['en', 'pl'], POTDOMAIN='foo') # foo.pot -- > [en.po, pl.pl]

Example 4. Update files for languages defined in LINGUAS file. The
files are updated from messages.pot template:

# ...
env.POUpdate(LINGUAS_FILE = 1) # needs 'LINGUAS' file

Example 5. Same as above, but update from foo.pot template:

# ...
env.POUpdate(LINGUAS_FILE = 1, source = ['foo'])

Example 6. Update en.po and pl.po plus files for languages defined
in LINGUAS file. The files are updated from messages.pot template:

# produce 'en.po', 'pl.po' + files defined in 'LINGUAS':
env.POUpdate(['en', 'pl' ], LINGUAS_FILE = 1)

Example 7. Use $POAUTOINIT to automatically initialize PO file if
it doesn't exist:

# ...
env.POUpdate(LINGUAS_FILE = 1, POAUTOINIT = 1)

Example 8. Update PO files for languages defined in LINGUAS file.
The files are updated from foo.pot template. All necessary settings
are pre-configured via environment.

# ...
env['POAUTOINIT'] = 1
env['LINGUAS_FILE'] = 1
env['POTDOMAIN'] = 'foo'
env.POUpdate()

Program(), env.Program()
Builds an executable given one or more object files or C, C++, D,
or Fortran source files. If any C, C++, D or Fortran source files
are specified, then they will be automatically compiled to object
files using the Object builder method; see that builder method's
description for a list of legal source file suffixes and how they
are interpreted. The target executable file prefix, specified by
the $PROGPREFIX construction variable (nothing by default), and
suffix, specified by the $PROGSUFFIX construction variable (by
default, .exe on Windows systems, nothing on POSIX systems), are
automatically added to the target if not already present. Example:

env.Program(target='foo', source=['foo.o', 'bar.c', 'baz.f'])

ProgramAllAtOnce(), env.ProgramAllAtOnce()
Builds an executable from D sources without first creating
individual objects for each file.

D sources can be compiled file-by-file as C and C++ source are, and
D is integrated into the scons Object and Program builders for this
model of build. D codes can though do whole source meta-programming
(some of the testing frameworks do this). For this it is imperative
that all sources are compiled and linked in a single call to the D
compiler. This builder serves that purpose.

env.ProgramAllAtOnce('executable', ['mod_a.d, mod_b.d', 'mod_c.d'])

This command will compile the modules mod_a, mod_b, and mod_c in a
single compilation process without first creating object files for
the modules. Some of the D compilers will create executable.o
others will not.

RES(), env.RES()
Builds a Microsoft Visual C++ resource file. This builder method is
only provided when Microsoft Visual C++ or MinGW is being used as
the compiler. The .res (or .o for MinGW) suffix is added to the
target name if no other suffix is given. The source file is scanned
for implicit dependencies as though it were a C file. Example:

env.RES('resource.rc')

RMIC(), env.RMIC()
Builds stub and skeleton class files for remote objects from Java
.class files. The target is a directory relative to which the stub
and skeleton class files will be written. The source can be the
names of .class files, or the objects return from the Java builder
method.

If the construction variable $JAVACLASSDIR is set, either in the
environment or in the call to the RMIC builder method itself, then
the value of the variable will be stripped from the beginning of
any .class file names.

classes = env.Java(target = 'classdir', source = 'src')
env.RMIC(target = 'outdir1', source = classes)

env.RMIC(target = 'outdir2',
source = ['package/foo.class', 'package/bar.class'])

env.RMIC(target = 'outdir3',
source = ['classes/foo.class', 'classes/bar.class'],
JAVACLASSDIR = 'classes')

RPCGenClient(), env.RPCGenClient()
Generates an RPC client stub (_clnt.c) file from a specified RPC
(.x) source file. Because rpcgen only builds output files in the
local directory, the command will be executed in the source file's
directory by default.

# Builds src/rpcif_clnt.c
env.RPCGenClient('src/rpcif.x')

RPCGenHeader(), env.RPCGenHeader()
Generates an RPC header (.h) file from a specified RPC (.x) source
file. Because rpcgen only builds output files in the local
directory, the command will be executed in the source file's
directory by default.

# Builds src/rpcif.h
env.RPCGenHeader('src/rpcif.x')

RPCGenService(), env.RPCGenService()
Generates an RPC server-skeleton (_svc.c) file from a specified RPC
(.x) source file. Because rpcgen only builds output files in the
local directory, the command will be executed in the source file's
directory by default.

# Builds src/rpcif_svc.c
env.RPCGenClient('src/rpcif.x')

RPCGenXDR(), env.RPCGenXDR()
Generates an RPC XDR routine (_xdr.c) file from a specified RPC
(.x) source file. Because rpcgen only builds output files in the
local directory, the command will be executed in the source file's
directory by default.

# Builds src/rpcif_xdr.c
env.RPCGenClient('src/rpcif.x')

SharedLibrary(), env.SharedLibrary()
Builds a shared library (.so on a POSIX system, .dll on Windows)
given one or more object files or C, C++, D or Fortran source
files. If any source files are given, then they will be
automatically compiled to object files. The target library file
prefix, specified by the $SHLIBPREFIX construction variable (by
default, lib on POSIX systems, nothing on Windows systems), and
suffix, specified by the $SHLIBSUFFIX construction variable (by
default, .dll on Windows systems, .so on POSIX systems), are
automatically added to the target if not already present. Example:

env.SharedLibrary(target='bar', source=['bar.c', 'foo.o'])

On Windows systems, the SharedLibrary builder method will always
build an import library (.lib) in addition to the shared library
(.dll), adding a .lib library with the same basename if there is
not already a .lib file explicitly listed in the targets.

On Cygwin systems, the SharedLibrary builder method will always
build an import library (.dll.a) in addition to the shared library
(.dll), adding a .dll.a library with the same basename if there is
not already a .dll.a file explicitly listed in the targets.

Any object files listed in the source must have been built for a
shared library (that is, using the SharedObject builder method).
scons will raise an error if there is any mismatch.

On some platforms, there is a distinction between a shared library
(loaded automatically by the system to resolve external references)
and a loadable module (explicitly loaded by user action). For
maximum portability, use the LoadableModule builder for the latter.

When the $SHLIBVERSION construction variable is defined, a
versioned shared library is created. This modifies $SHLINKFLAGS as
required, adds the version number to the library name, and creates
any symbolic links that are needed.

env.SharedLibrary(target='bar', source=['bar.c', 'foo.o'], SHLIBVERSION='1.5.2')

On a POSIX system, versions with a single token create exactly one
symlink: libbar.so.6 would have symlink libbar.so only. On a POSIX
system, versions with two or more tokens create exactly two
symlinks: libbar.so.2.3.1 would have symlinks libbar.so and
libbar.so.2; on a Darwin (OSX) system the library would be
libbar.2.3.1.dylib and the link would be libbar.dylib.

On Windows systems, specifying register=1 will cause the .dll to be
registered after it is built. The command that is run is determined
by the $REGSVR construction variable (regsvr32 by default), and the
flags passed are determined by $REGSVRFLAGS. By default,
$REGSVRFLAGS includes the /s option, to prevent dialogs from
popping up and requiring user attention when it is run. If you
change $REGSVRFLAGS, be sure to include the /s option. For example,

env.SharedLibrary(target='bar', source=['bar.cxx', 'foo.obj'], register=1)

will register bar.dll as a COM object when it is done linking it.

SharedObject(), env.SharedObject()
Builds an object file intended for inclusion in a shared library.
Source files must have one of the same set of extensions specified
above for the StaticObject builder method. On some platforms
building a shared object requires additional compiler option (e.g.
-fPIC for gcc) in addition to those needed to build a normal
(static) object, but on some platforms there is no difference
between a shared object and a normal (static) one. When there is a
difference, SCons will only allow shared objects to be linked into
a shared library, and will use a different suffix for shared
objects. On platforms where there is no difference, SCons will
allow both normal (static) and shared objects to be linked into a
shared library, and will use the same suffix for shared and normal
(static) objects. The target object file prefix, specified by the
$SHOBJPREFIX construction variable (by default, the same as
$OBJPREFIX), and suffix, specified by the $SHOBJSUFFIX construction
variable, are automatically added to the target if not already
present. Examples:

env.SharedObject(target='ddd', source='ddd.c')
env.SharedObject(target='eee.o', source='eee.cpp')
env.SharedObject(target='fff.obj', source='fff.for')

Note that the source files will be scanned according to the suffix
mappings in the SourceFileScanner object. See the manpage section
"Scanner Objects" for more information.

StaticLibrary(), env.StaticLibrary()
Builds a static library given one or more object files or C, C++, D
or Fortran source files. If any source files are given, then they
will be automatically compiled to object files. The static library
file prefix, specified by the $LIBPREFIX construction variable (by
default, lib on POSIX systems, nothing on Windows systems), and
suffix, specified by the $LIBSUFFIX construction variable (by
default, .lib on Windows systems, .a on POSIX systems), are
automatically added to the target if not already present. Example:

env.StaticLibrary(target='bar', source=['bar.c', 'foo.o'])

Any object files listed in the source must have been built for a
static library (that is, using the StaticObject builder method).
scons will raise an error if there is any mismatch.

StaticObject(), env.StaticObject()
Builds a static object file from one or more C, C++, D, or Fortran
source files. Source files must have one of the following
extensions:

.asm assembly language file
.ASM assembly language file
.c C file
.C Windows: C file
POSIX: C++ file
.cc C++ file
.cpp C++ file
.cxx C++ file
.cxx C++ file
.c++ C++ file
.C++ C++ file
.d D file
.f Fortran file
.F Windows: Fortran file
POSIX: Fortran file + C pre-processor
.for Fortran file
.FOR Fortran file
.fpp Fortran file + C pre-processor
.FPP Fortran file + C pre-processor
.m Object C file
.mm Object C++ file
.s assembly language file
.S Windows: assembly language file
ARM: CodeSourcery Sourcery Lite
.sx assembly language file + C pre-processor
POSIX: assembly language file + C pre-processor
.spp assembly language file + C pre-processor
.SPP assembly language file + C pre-processor

The target object file prefix, specified by the $OBJPREFIX
construction variable (nothing by default), and suffix, specified
by the $OBJSUFFIX construction variable (.obj on Windows systems,
.o on POSIX systems), are automatically added to the target if not
already present. Examples:

env.StaticObject(target='aaa', source='aaa.c')
env.StaticObject(target='bbb.o', source='bbb.c++')
env.StaticObject(target='ccc.obj', source='ccc.f')

Note that the source files will be scanned according to the suffix
mappings in the SourceFileScanner object. See the manpage section
"Scanner Objects" for more information.

Substfile(), env.Substfile()
The Substfile builder creates a single text file from a template
consisting of a file or set of files (or nodes), replacing text
using the $SUBST_DICT construction variable (if set). If a set,
they are concatenated into the target file using the value of the
$LINESEPARATOR construction variable as a separator between
contents; the separator is not emitted after the contents of the
last file. Nested lists of source files are flattened. See also
Textfile.

If a single source file name is specified and has a .in suffix, the
suffix is stripped and the remainder of the name is used as the
default target name.

The prefix and suffix specified by the $SUBSTFILEPREFIX and
$SUBSTFILESUFFIX construction variables (an empty string by default
in both cases) are automatically added to the target if they are
not already present.

If a construction variable named $SUBST_DICT is present, it may be
either a Python dictionary or a sequence of (key, value) tuples. If
it is a dictionary it is converted into a list of tuples with
unspecified order, so if one key is a prefix of another key or if
one substitution could be further expanded by another subsitition,
it is unpredictable whether the expansion will occur.

Any occurrences of a key in the source are replaced by the
corresponding value, which may be a Python callable function or a
string. If the value is a callable, it is called with no arguments
to get a string. Strings are subst-expanded and the result replaces
the key.

env = Environment(tools=['default'])

env['prefix'] = '/usr/bin'
script_dict = {'@prefix@': '/bin', '@exec_prefix@': '$prefix'}
env.Substfile('script.in', SUBST_DICT=script_dict)

conf_dict = {'%VERSION%': '1.2.3', '%BASE%': 'MyProg'}
env.Substfile('config.h.in', conf_dict, SUBST_DICT=conf_dict)

# UNPREDICTABLE - one key is a prefix of another
bad_foo = {'$foo': '$foo', '$foobar': '$foobar'}
env.Substfile('foo.in', SUBST_DICT=bad_foo)

# PREDICTABLE - keys are applied longest first
good_foo = [('$foobar', '$foobar'), ('$foo', '$foo')]
env.Substfile('foo.in', SUBST_DICT=good_foo)

# UNPREDICTABLE - one substitution could be futher expanded
bad_bar = {'@bar@': '@soap@', '@soap@': 'lye'}
env.Substfile('bar.in', SUBST_DICT=bad_bar)

# PREDICTABLE - substitutions are expanded in order
good_bar = (('@bar@', '@soap@'), ('@soap@', 'lye'))
env.Substfile('bar.in', SUBST_DICT=good_bar)

# the SUBST_DICT may be in common (and not an override)
substutions = {}
subst = Environment(tools=['textfile'], SUBST_DICT=substitutions)
substitutions['@foo@'] = 'foo'
subst['SUBST_DICT']['@bar@'] = 'bar'
subst.Substfile(
'pgm1.c',
[Value('#include "@foo@.h"'), Value('#include "@bar@.h"'), "common.in", "pgm1.in"],
)
subst.Substfile(
'pgm2.c',
[Value('#include "@foo@.h"'), Value('#include "@bar@.h"'), "common.in", "pgm2.in"],
)

Tar(), env.Tar()
Builds a tar archive of the specified files and/or directories.
Unlike most builder methods, the Tar builder method may be called
multiple times for a given target; each additional call adds to the
list of entries that will be built into the archive. Any source
directories will be scanned for changes to any on-disk files,
regardless of whether or not scons knows about them from other
Builder or function calls.

env.Tar('src.tar', 'src')

# Create the stuff.tar file.
env.Tar('stuff', ['subdir1', 'subdir2'])
# Also add "another" to the stuff.tar file.
env.Tar('stuff', 'another')

# Set TARFLAGS to create a gzip-filtered archive.
env = Environment(TARFLAGS = '-c -z')
env.Tar('foo.tar.gz', 'foo')

# Also set the suffix to .tgz.
env = Environment(TARFLAGS = '-c -z',
TARSUFFIX = '.tgz')
env.Tar('foo')

Textfile(), env.Textfile()
The Textfile builder generates a single text file from a template
consisting of a list of strings, replacing text using the
$SUBST_DICT construction variable (if set) - see Substfile for a
description of replacement. The strings will be separated in the
target file using the value of the $LINESEPARATOR construction
variable; the line separator is not emitted after the last string.
Nested lists of source strings are flattened. Source strings need
not literally be Python strings: they can be Nodes or Python
objects that convert cleanly to Value nodes

The prefix and suffix specified by the $TEXTFILEPREFIX and
$TEXTFILESUFFIX construction variables (by default an empty string
and .txt, respectively) are automatically added to the target if
they are not already present. Examples:

# builds/writes foo.txt
env.Textfile(target='foo.txt', source=['Goethe', 42, 'Schiller'])

# builds/writes bar.txt
env.Textfile(target='bar', source=['lalala', 'tanteratei'], LINESEPARATOR='|*')

# nested lists are flattened automatically
env.Textfile(target='blob', source=['lalala', ['Goethe', 42, 'Schiller'], 'tanteratei'])

# files may be used as input by wraping them in File()
env.Textfile(
target='concat', # concatenate files with a marker between
source=[File('concat1'), File('concat2')],
LINESEPARATOR='====================\n',
)

Results:

foo.txt

Goethe
42
Schiller

bar.txt

lalala|*tanteratei

blob.txt

lalala
Goethe
42
Schiller
tanteratei

Translate(), env.Translate()
This pseudo-builder belongs to gettext toolset. The builder
extracts internationalized messages from source files, updates POT
template (if necessary) and then updates PO translations (if
necessary). If $POAUTOINIT is set, missing PO files will be
automatically created (i.e. without translator person
intervention). The variables $LINGUAS_FILE and $POTDOMAIN are taken
into acount too. All other construction variables used by
POTUpdate, and POUpdate work here too.

Example 1. The simplest way is to specify input files and output
languages inline in a SCons script when invoking Translate

# SConscript in 'po/' directory
env = Environment( tools = ["default", "gettext"] )
env['POAUTOINIT'] = 1
env.Translate(['en','pl'], ['../a.cpp','../b.cpp'])

Example 2. If you wish, you may also stick to conventional style
known from autotools, i.e. using POTFILES.in and LINGUAS files

# LINGUAS
en pl
#end

# POTFILES.in
a.cpp
b.cpp
# end

# SConscript
env = Environment( tools = ["default", "gettext"] )
env['POAUTOINIT'] = 1
env['XGETTEXTPATH'] = ['../']
env.Translate(LINGUAS_FILE = 1, XGETTEXTFROM = 'POTFILES.in')

The last approach is perhaps the recommended one. It allows easily
split internationalization/localization onto separate SCons
scripts, where a script in source tree is responsible for
translations (from sources to PO files) and script(s) under variant
directories are responsible for compilation of PO to MO files to
and for installation of MO files. The "gluing factor" synchronizing
these two scripts is then the content of LINGUAS file. Note, that
the updated POT and PO files are usually going to be committed back
to the repository, so they must be updated within the source
directory (and not in variant directories). Additionaly, the file
listing of po/ directory contains LINGUAS file, so the source tree
looks familiar to translators, and they may work with the project
in their usual way.

Example 3. Let's prepare a development tree as below

project/
+ SConstruct
+ build/
+ src/
+ po/
+ SConscript
+ SConscript.i18n
+ POTFILES.in
+ LINGUAS

with build being variant directory. Write the top-level SConstruct
script as follows

# SConstruct
env = Environment( tools = ["default", "gettext"] )
VariantDir('build', 'src', duplicate = 0)
env['POAUTOINIT'] = 1
SConscript('src/po/SConscript.i18n', exports = 'env')
SConscript('build/po/SConscript', exports = 'env')

the src/po/SConscript.i18n as

# src/po/SConscript.i18n
Import('env')
env.Translate(LINGUAS_FILE=1, XGETTEXTFROM='POTFILES.in', XGETTEXTPATH=['../'])

and the src/po/SConscript

# src/po/SConscript
Import('env')
env.MOFiles(LINGUAS_FILE = 1)

Such setup produces POT and PO files under source tree in src/po/
and binary MO files under variant tree in build/po/. This way the
POT and PO files are separated from other output files, which must
not be committed back to source repositories (e.g. MO files).

Note
In above example, the PO files are not updated, nor created
automatically when you issue scons '.' command. The files must
be updated (created) by hand via scons po-update and then MO
files can be compiled by running scons '.'.

TypeLibrary(), env.TypeLibrary()
Builds a Windows type library (.tlb) file from an input IDL file
(.idl). In addition, it will build the associated interface stub
and proxy source files, naming them according to the base name of
the .idl file. For example,

env.TypeLibrary(source="foo.idl")

Will create foo.tlb, foo.h, foo_i.c, foo_p.c and foo_data.c files.

Uic(), env.Uic()
Builds a header file, an implementation file and a moc file from an
ui file. and returns the corresponding nodes in the above order.
This builder is only available after using the tool 'qt'. Note: you
can specify .ui files directly as source files to the Program,
Library and SharedLibrary builders without using this builder.
Using this builder lets you override the standard naming
conventions (be careful: prefixes are always prepended to names of
built files; if you don't want prefixes, you may set them to ``).
See the $QTDIR variable for more information. Example:

env.Uic('foo.ui') # -> ['foo.h', 'uic_foo.cc', 'moc_foo.cc']
env.Uic(target = Split('include/foo.h gen/uicfoo.cc gen/mocfoo.cc'),
source = 'foo.ui') # -> ['include/foo.h', 'gen/uicfoo.cc', 'gen/mocfoo.cc']

Zip(), env.Zip()
Builds a zip archive of the specified files and/or directories.
Unlike most builder methods, the Zip builder method may be called
multiple times for a given target; each additional call adds to the
list of entries that will be built into the archive. Any source
directories will be scanned for changes to any on-disk files,
regardless of whether or not scons knows about them from other
Builder or function calls.

env.Zip('src.zip', 'src')

# Create the stuff.zip file.
env.Zip('stuff', ['subdir1', 'subdir2'])
# Also add "another" to the stuff.tar file.
env.Zip('stuff', 'another')

All targets of builder methods automatically depend on their sources.
An explicit dependency can be specified using the env.Depends method of
a construction environment (see below).

In addition, scons automatically scans source files for various
programming languages, so the dependencies do not need to be specified
explicitly. By default, SCons can C source files, C++ source files,
Fortran source files with .F (POSIX systems only), .fpp, or .FPP file
extensions, and assembly language files with .S (POSIX systems only),
.spp, or .SPP files extensions for C preprocessor dependencies. SCons
also has default support for scanning D source files, You can also
write your own Scanners to add support for additional source file
types. These can be added to the default Scanner object used by the
Object, StaticObject and SharedObject Builders by adding them to the
SourceFileScanner object. See the section called "Scanner Objects" for
more information about defining your own Scanner objects and using the
SourceFileScanner object.

Methods and Functions To Do Things
In addition to Builder methods, scons provides a number of other
construction environment methods and global functions to manipulate the
build configuration.

Usually, a construction environment method and global function with the
same name both exist for convenience. In the following list, the global
function is documented in this style:

Function(arguments, [optional arguments])

and the construction environment method looks like:

env.Function(arguments, [optional arguments])

If the function can be called both ways, then both forms are listed.

The global function and same-named construction environment method
provide almost identical functionality, with a couple of exceptions.
First, many of the construction environment methods affect only that
construction environment, while the global function has a global
effect. Second, where appropriate, calling the functionality through a
construction environment will substitute construction variables into
any supplied string arguments, while the global function doesn't have
the context of a construction environment to pick variables from, so it
cannot perform the substitution. For example:

Default('$FOO')

env = Environment(FOO='foo')
env.Default('$FOO')

In the above example, the call to the global Default function will add
a target named $FOO to the list of default targets, while the call to
the env.Default construction environment method will expand the value
and add a target named foo to the list of default targets. For more on
construction variable expansion, see the next section on construction
variables.

Global functions may be called from custom Python modules that you
import into an SConscript file by adding the following import to the
Python module:

from SCons.Script import *

Construction environment methods and global functions provided by scons
include:

Action(action, [output, [var, ...]] [key=value, ...]),
env.Action(action, [output, [var, ...]] [key=value, ...])
A factory function to create an Action object for the specified
action. See the manpage section "Action Objects" for a complete
explanation of the arguments and behavior.

Note that the env.Action form of the invocation will expand
construction variables in any argument strings, including the
action argument, at the time it is called using the construction
variables in the env construction environment through which
env.Action was called. The Action global function form delays all
variable expansion until the Action object is actually used.

AddMethod(object, function, [name]), env.AddMethod(function, [name])
Adds function to an object as a method. function will be called
with an instance object as the first argument as for other methods.
If name is given, it is used as the name of the new method, else
the name of function is used.

When the global function AddMethod is called, the object to add the
method to must be passed as the first argument; typically this will
be Environment, in order to create a method which applies to all
construction environments subsequently constructed. When called
using the env.AddMethod form, the method is added to the specified
construction environment only. Added methods propagate through
env.Clone calls.

Examples:

# Function to add must accept an instance argument.
# The Python convention is to call this 'self'.
def my_method(self, arg):
print("my_method() got", arg)

# Use the global function to add a method to the Environment class:
AddMethod(Environment, my_method)
env = Environment()
env.my_method('arg')

# Use the optional name argument to set the name of the method:
env.AddMethod(my_method, 'other_method_name')
env.other_method_name('another arg')

AddOption(arguments)
Adds a local (project-specific) command-line option. arguments are
the same as those supported by the add_option method in the
standard Python library module optparse, with a few additional
capabilities noted below. See the documentation for optparse for a
thorough discussion of its option-processing capabities.

In addition to the arguments and values supported by the optparse
add_option method, AddOption allows setting the nargs keyword value
to a string consisting of a question mark ('?') to indicate that
the option argument for that option string is optional. If the
option string is present on the command line but has no matching
option argument, the value of the const keyword argument is
produced as the value of the option. If the option string is
omitted from the command line, the value of the default keyword
argument is produced, as usual; if there is no default keyword
argument in the AddOption call, None is produced.

optparse recognizes abbreviations of long option names, as long as
they can be unambiguously resolved. For example, if add_option is
called to define a --devicename option, it will recognize --device,
--dev and so forth as long as there is no other option which could
also match to the same abbreviation. Options added via AddOption do
not support the automatic recognition of abbreviations. Instead, to
allow specific abbreviations, include them as synonyms in the
AddOption call itself.

Once a new command-line option has been added with AddOption, the
option value may be accessed using GetOption or env.GetOption.
SetOption is not currently supported for options added with
AddOption.

Help text for an option is a combination of the string supplied in
the help keyword argument to AddOption and information collected
from the other keyword arguments. Such help is displayed if the -h
command line option is used (but not with -H). Help for all local
options is displayed under the separate heading Local Options. The
options are unsorted - they will appear in the help text in the
order in which the AddOption calls occur.

Example:

AddOption(
'--prefix',
dest='prefix',
nargs=1,
type='string',
action='store',
metavar='DIR',
help='installation prefix',
)
env = Environment(PREFIX=GetOption('prefix'))

For that example, the following help text would be produced:

Local Options:
--prefix=DIR installation prefix

Help text for local options may be unavailable if the Help function
has been called, see the Help documentation for details.

Note
As an artifact of the internal implementation, the behavior of
options added by AddOption which take option arguments is
undefined if whitespace (rather than an = sign) is used as the
separator on the command line. Users should avoid such usage;
it is recommended to add a note to this effect to project
documentation if the situation is likely to arise. In addition,
if the nargs keyword is used to specify more than one following
option argument (that is, with a value of 2 or greater), such
arguments would necessarily be whitespace separated, triggering
the issue. Developers should not use AddOption this way. Future
versions of SCons will likely forbid such usage.

AddPostAction(target, action), env.AddPostAction(target, action)
Arranges for the specified action to be performed after the
specified target has been built. The specified action(s) may be an
Action object, or anything that can be converted into an Action
object See the manpage section "Action Objects" for a complete
explanation.

When multiple targets are supplied, the action may be called
multiple times, once after each action that generates one or more
targets in the list.

AddPreAction(target, action), env.AddPreAction(target, action)
Arranges for the specified action to be performed before the
specified target is built. The specified action(s) may be an Action
object, or anything that can be converted into an Action object See
the manpage section "Action Objects" for a complete explanation.

When multiple targets are specified, the action(s) may be called
multiple times, once before each action that generates one or more
targets in the list.

Note that if any of the targets are built in multiple steps, the
action will be invoked just before the "final" action that
specifically generates the specified target(s). For example, when
building an executable program from a specified source .c file via
an intermediate object file:

foo = Program('foo.c')
AddPreAction(foo, 'pre_action')

The specified pre_action would be executed before scons calls the
link command that actually generates the executable program binary
foo, not before compiling the foo.c file into an object file.

Alias(alias, [targets, [action]]), env.Alias(alias, [targets,
[action]])
Creates one or more phony targets that expand to one or more other
targets. An optional action (command) or list of actions can be
specified that will be executed whenever the any of the alias
targets are out-of-date. Returns the Node object representing the
alias, which exists outside of any file system. This Node object,
or the alias name, may be used as a dependency of any other target,
including another alias. Alias can be called multiple times for
the same alias to add additional targets to the alias, or
additional actions to the list for this alias. Aliases are global
even if set through the construction environment method.

Examples:

Alias('install')
Alias('install', '/usr/bin')
Alias(['install', 'install-lib'], '/usr/local/lib')

env.Alias('install', ['/usr/local/bin', '/usr/local/lib'])
env.Alias('install', ['/usr/local/man'])

env.Alias('update', ['file1', 'file2'], "update_database $SOURCES")

AllowSubstExceptions([exception, ...])
Specifies the exceptions that will be allowed when expanding
construction variables. By default, any construction variable
expansions that generate a NameError or IndexError exception will
expand to a '' (an empty string) and not cause scons to fail. All
exceptions not in the specified list will generate an error message
and terminate processing.

If AllowSubstExceptions is called multiple times, each call
completely overwrites the previous list of allowed exceptions.

Example:

# Requires that all construction variable names exist.
# (You may wish to do this if you want to enforce strictly
# that all construction variables must be defined before use.)
AllowSubstExceptions()

# Also allow a string containing a zero-division expansion
# like '${1 / 0}' to evalute to ''.
AllowSubstExceptions(IndexError, NameError, ZeroDivisionError)

AlwaysBuild(target, ...), env.AlwaysBuild(target, ...)
Marks each given target so that it is always assumed to be out of
date, and will always be rebuilt if needed. Note, however, that
AlwaysBuild does not add its target(s) to the default target list,
so the targets will only be built if they are specified on the
command line, or are a dependent of a target specified on the
command line--but they will always be built if so specified.
Multiple targets can be passed in to a single call to AlwaysBuild.

env.Append(key=val, [...])
Intelligently append values to construction variables in the
construction environment named by env. The construction variables
and values to add to them are passed as key=val pairs (Python
keyword arguments). env.Append is designed to allow adding values
without normally having to know the data type of an existing
construction variable. Regular Python syntax can also be used to
manipulate the construction variable, but for that you must know
the type of the construction variable: for example, different
Python syntax is needed to combine a list of values with a single
string value, or vice versa. Some pre-defined construction
variables do have type expectations based on how SCons will use
them, for example $CPPDEFINES is normally a string or a list of
strings, but can be a string, a list of strings, a list of tuples,
or a dictionary, while $LIBEMITTER would expect a callable or list
of callables, and $BUILDERS would expect a mapping type. Consult
the documentation for the various construction variables for more
details.

The following descriptions apply to both the append and prepend
functions, the only difference being the insertion point of the
added values.

If env. does not have a construction variable indicated by key, val
is added to the environment under that key as-is.

val can be almost any type, and SCons will combine it with an
existing value into an appropriate type, but there are a few
special cases to be aware of. When two strings are combined, the
result is normally a new string, with the caller responsible for
supplying any needed separation. The exception to this is the
construction variable $CPPDEFINES, in which each item will be
postprocessed by adding a prefix and/or suffix, so the contents are
treated as a list of strings, that is, adding a string will result
in a separate string entry, not a combined string. For $CPPDEFINES
as well as for $LIBS, and the various *PATH variables, SCons will
supply the compiler-specific syntax (e.g. adding a -D or /D prefix
for $CPPDEFINES), so this syntax should be omitted when adding
values to these variables. Example (gcc syntax shown in the
expansion of CPPDEFINES):

env = Environment(CXXFLAGS="-std=c11", CPPDEFINES="RELEASE")
print("CXXFLAGS={}, CPPDEFINES={}".format(env['CXXFLAGS'], env['CPPDEFINES']))
# notice including a leading space in CXXFLAGS value
env.Append(CXXFLAGS=" -O", CPPDEFINES="EXTRA")
print("CXXFLAGS={}, CPPDEFINES={}".format(env['CXXFLAGS'], env['CPPDEFINES']))
print("CPPDEFINES will expand to {}".format(env.subst("$_CPPDEFFLAGS")))

$ scons -Q
CXXFLAGS=-std=c11, CPPDEFINES=RELEASE
CXXFLAGS=-std=c11 -O, CPPDEFINES=['RELEASE', 'EXTRA']
CPPDEFINES will expand to -DRELEASE -DEXTRA
scons: `.' is up to date.

Because $CPPDEFINES is intended to describe C/C++ pre-processor
macro definitions, it accepts additional syntax. Preprocessor
macros can be valued, or un-valued, as in -DBAR=1 or -DFOO. The
macro can be be supplied as a complete string including the value,
or as a tuple (or list) of macro, value, or as a dictionary.
Example (again gcc syntax in the expanded defines):

env = Environment(CPPDEFINES="FOO")
print("CPPDEFINES={}".format(env['CPPDEFINES']))
env.Append(CPPDEFINES="BAR=1")
print("CPPDEFINES={}".format(env['CPPDEFINES']))
env.Append(CPPDEFINES=("OTHER", 2))
print("CPPDEFINES={}".format(env['CPPDEFINES']))
env.Append(CPPDEFINES={"EXTRA": "arg"})
print("CPPDEFINES={}".format(env['CPPDEFINES']))
print("CPPDEFINES will expand to {}".format(env.subst("$_CPPDEFFLAGS")))

$ scons -Q
CPPDEFINES=FOO
CPPDEFINES=['FOO', 'BAR=1']
CPPDEFINES=['FOO', 'BAR=1', ('OTHER', 2)]
CPPDEFINES=['FOO', 'BAR=1', ('OTHER', 2), {'EXTRA': 'arg'}]
CPPDEFINES will expand to -DFOO -DBAR=1 -DOTHER=2 -DEXTRA=arg
scons: `.' is up to date.

Adding a string val to a dictonary construction variable will enter
val as the key in the dict, and None as its value. Using a tuple
type to supply a key + value only works for the special case of
$CPPDEFINES described above.

Although most combinations of types work without needing to know
the details, some combinations do not make sense and a Python
exception will be raised.

When using env.Append to modify construction variables which are
path specifications (normally, those names which end in PATH), it
is recommended to add the values as a list of strings, even if
there is only a single string to add. The same goes for adding
library names to $LIBS.

env.Append(CPPPATH=["#/include"])

See also env.AppendUnique, env.Prepend and env.PrependUnique.

env.AppendENVPath(name, newpath, [envname, sep, delete_existing=False])
Append new path elements to the given path in the specified
external environment ($ENV by default). This will only add any
particular path once (leaving the last one it encounters and
ignoring the rest, to preserve path order), and to help assure
this, will normalize all paths (using os.path.normpath and
os.path.normcase). This can also handle the case where the given
old path variable is a list instead of a string, in which case a
list will be returned instead of a string.

If delete_existing is False, then adding a path that already exists
will not move it to the end; it will stay where it is in the list.

Example:

print('before:', env['ENV']['INCLUDE'])
include_path = '/foo/bar:/foo'
env.AppendENVPath('INCLUDE', include_path)
print('after:', env['ENV']['INCLUDE'])

Yields:

before: /foo:/biz
after: /biz:/foo/bar:/foo

env.AppendUnique(key=val, [...], delete_existing=False)
Append values to construction variables in the current construction
environment, maintaining uniqueness. Works like env.Append (see for
details), except that values already present in the construction
variable will not be added again. If delete_existing is True, the
existing matching value is first removed, and the requested value
is added, having the effect of moving such values to the end.

Example:

env.AppendUnique(CCFLAGS='-g', FOO=['foo.yyy'])

See also env.Append, env.Prepend and env.PrependUnique.

Builder(action, [arguments]), env.Builder(action, [arguments])
Creates a Builder object for the specified action. See the manpage
section "Builder Objects" for a complete explanation of the
arguments and behavior.

Note that the env.Builder() form of the invocation will expand
construction variables in any arguments strings, including the
action argument, at the time it is called using the construction
variables in the env construction environment through which
env.Builder was called. The Builder form delays all variable
expansion until after the Builder object is actually called.

CacheDir(cache_dir, custom_class=None), env.CacheDir(cache_dir,
custom_class=None)
Direct scons to maintain a derived-file cache in cache_dir. The
derived files in the cache will be shared among all the builds
specifying the same cache_dir. Specifying a cache_dir of None
disables derived file caching.

When specifying a custom_class which should be a class type which
is a subclass of SCons.CacheDir.CacheDir, SCons will internally
invoke this class to use for performing caching operations. This
argument is optional and if left to default None, will use the
default SCons.CacheDir.CacheDir class.

Calling the environment method env.CacheDir limits the effect to
targets built through the specified construction environment.
Calling the global function CacheDir sets a global default that
will be used by all targets built through construction environments
that do not set up environment-specific caching by calling
env.CacheDir.

When derived-file caching is being used and scons finds a derived
file that needs to be rebuilt, it will first look in the cache to
see if a file with matching build signature exists (indicating the
input file(s) and build action(s) were identical to those for the
current target), and if so, will retrieve the file from the cache.
scons will report Retrieved `file' from cache instead of the normal
build message. If the derived file is not present in the cache,
scons will build it and then place a copy of the built file in the
cache, identified by its build signature, for future use.

The Retrieved `file' from cache messages are useful for human
consumption, but less so when comparing log files between scons
runs which will show differences that are noisy and not actually
significant. To disable, use the --cache-show option. With this
option, scons will print the action that would have been used to
build the file without considering cache retrieval.

Derived-file caching may be disabled for any invocation of scons by
giving the --cache-disable command line option. Cache updating may
be disabled, leaving cache fetching enabled, by giving the
--cache-readonly.

If the --cache-force option is used, scons will place a copy of all
derived files in the cache, even if they already existed and were
not built by this invocation. This is useful to populate a cache
the first time a cache_dir is used for a build, or to bring a cache
up to date after a build with cache updating disabled
(--cache-disable or --cache-readonly) has been done.

The NoCache method can be used to disable caching of specific
files. This can be useful if inputs and/or outputs of some tool are
impossible to predict or prohibitively large.

Clean(targets, files_or_dirs), env.Clean(targets, files_or_dirs)
This specifies a list of files or directories which should be
removed whenever the targets are specified with the -c command line
option. The specified targets may be a list or an individual
target. Multiple calls to Clean are legal, and create new targets
or add files and directories to the clean list for the specified
targets.

Multiple files or directories should be specified either as
separate arguments to the Clean method, or as a list. Clean will
also accept the return value of any of the construction environment
Builder methods. Examples:

The related NoClean function overrides calling Clean for the same
target, and any targets passed to both functions will not be
removed by the -c option.

Examples:

Clean('foo', ['bar', 'baz'])
Clean('dist', env.Program('hello', 'hello.c'))
Clean(['foo', 'bar'], 'something_else_to_clean')

In this example, installing the project creates a subdirectory for
the documentation. This statement causes the subdirectory to be
removed if the project is deinstalled.

Clean(docdir, os.path.join(docdir, projectname))

env.Clone([key=val, ...])
Returns a separate copy of a construction environment. If there are
any keyword arguments specified, they are added to the returned
copy, overwriting any existing values for the keywords.

Example:

env2 = env.Clone()
env3 = env.Clone(CCFLAGS='-g')

Additionally, a list of tools and a toolpath may be specified, as
in the Environment constructor:

def MyTool(env):
env['FOO'] = 'bar'

env4 = env.Clone(tools=['msvc', MyTool])

The parse_flags keyword argument is also recognized to allow
merging command-line style arguments into the appropriate
construction variables (see env.MergeFlags).

# create an environment for compiling programs that use wxWidgets
wx_env = env.Clone(parse_flags='!wx-config --cflags --cxxflags')

Command(target, source, action, [key=val, ...]), env.Command(target,
source, action, [key=val, ...])
Executes a specific action (or list of actions) to build a target
file or files from a source file or files. This is more convenient
than defining a separate Builder object for a single special-case
build.

The Command function accepts source_scanner, target_scanner,
source_factory, and target_factory keyword arguments. These
arguments can be used to specify a Scanner object that will be used
to apply a custom scanner for a source or target. For example, the
global DirScanner object can be used if any of the sources will be
directories that must be scanned on-disk for changes to files that
aren't already specified in other Builder of function calls. The
*_factory arguments take a factory function that Command will use
to turn any sources or targets specified as strings into SCons
Nodes. See the manpage section "Builder Objects" for more
information about how these arguments work in a Builder.

Any other keyword arguments specified override any same-named
existing construction variables.

An action can be an external command, specified as a string, or a
callable Python object; see the manpage section "Action Objects"
for more complete information. Also note that a string specifying
an external command may be preceded by an at-sign (@) to suppress
printing the command in question, or by a hyphen (-) to ignore the
exit status of the external command.

Examples:

env.Command(
target='foo.out',
source='foo.in',
action="$FOO_BUILD < $SOURCES > $TARGET"
)

env.Command(
target='bar.out',
source='bar.in',
action=["rm -f $TARGET", "$BAR_BUILD < $SOURCES > $TARGET"],
ENV={'PATH': '/usr/local/bin/'},
)

import os
def rename(env, target, source):
os.rename('.tmp', str(target[0]))

env.Command(
target='baz.out',
source='baz.in',
action=["$BAZ_BUILD < $SOURCES > .tmp", rename],
)

Note that the Command function will usually assume, by default,
that the specified targets and/or sources are Files, if no other
part of the configuration identifies what type of entries they are.
If necessary, you can explicitly specify that targets or source
nodes should be treated as directories by using the Dir or env.Dir
functions.

Examples:

env.Command('ddd.list', Dir('ddd'), 'ls -l $SOURCE > $TARGET')

env['DISTDIR'] = 'destination/directory'
env.Command(env.Dir('$DISTDIR')), None, make_distdir)

Also note that SCons will usually automatically create any
directory necessary to hold a target file, so you normally don't
need to create directories by hand.

Configure(env, [custom_tests, conf_dir, log_file, config_h]),
env.Configure([custom_tests, conf_dir, log_file, config_h])
Creates a Configure object for integrated functionality similar to
GNU autoconf. See the manpage section "Configure Contexts" for a
complete explanation of the arguments and behavior.

Decider(function), env.Decider(function)
Specifies that all up-to-date decisions for targets built through
this construction environment will be handled by the specified
function. function can be the name of a function or one of the
following strings that specify the predefined decision function
that will be applied:

"timestamp-newer"
Specifies that a target shall be considered out of date and
rebuilt if the dependency's timestamp is newer than the target
file's timestamp. This is the behavior of the classic Make
utility, and make can be used a synonym for timestamp-newer.

"timestamp-match"
Specifies that a target shall be considered out of date and
rebuilt if the dependency's timestamp is different than the
timestamp recorded the last time the target was built. This
provides behavior very similar to the classic Make utility (in
particular, files are not opened up so that their contents can
be checksummed) except that the target will also be rebuilt if
a dependency file has been restored to a version with an
earlier timestamp, such as can happen when restoring files from
backup archives.

"content"
Specifies that a target shall be considered out of date and
rebuilt if the dependency's content has changed since the last
time the target was built, as determined be performing an
checksum on the dependency's contents and comparing it to the
checksum recorded the last time the target was built. MD5 can
be used as a synonym for content, but it is deprecated.

"content-timestamp"
Specifies that a target shall be considered out of date and
rebuilt if the dependency's content has changed since the last
time the target was built, except that dependencies with a
timestamp that matches the last time the target was rebuilt
will be assumed to be up-to-date and not rebuilt. This provides
behavior very similar to the content behavior of always
checksumming file contents, with an optimization of not
checking the contents of files whose timestamps haven't
changed. The drawback is that SCons will not detect if a file's
content has changed but its timestamp is the same, as might
happen in an automated script that runs a build, updates a
file, and runs the build again, all within a single second.
MD5-timestamp can be used as a synonym for content-timestamp,
but it is deprecated.

Examples:

# Use exact timestamp matches by default.
Decider('timestamp-match')

# Use hash content signatures for any targets built
# with the attached construction environment.
env.Decider('content')

In addition to the above already-available functions, the function
argument may be a Python function you supply. Such a function must
accept the following four arguments:

dependency
The Node (file) which should cause the target to be rebuilt if
it has "changed" since the last tme target was built.

target
The Node (file) being built. In the normal case, this is what
should get rebuilt if the dependency has "changed."

prev_ni
Stored information about the state of the dependency the last
time the target was built. This can be consulted to match
various file characteristics such as the timestamp, size, or
content signature.

repo_node
If set, use this Node instead of the one specified by
dependency to determine if the dependency has changed. This
argument is optional so should be written as a default argument
(typically it would be written as repo_node=None). A caller
will normally only set this if the target only exists in a
Repository.

The function should return a value which evaluates True if the
dependency has "changed" since the last time the target was built
(indicating that the target should be rebuilt), and a value which
evaluates False otherwise (indicating that the target should not be
rebuilt). Note that the decision can be made using whatever
criteria are appopriate. Ignoring some or all of the function
arguments is perfectly normal.

Example:

def my_decider(dependency, target, prev_ni, repo_node=None):
return not os.path.exists(str(target))

env.Decider(my_decider)

Default(target[, ...]), env.Default(target[, ...])
Specify default targets to the SCons target selection mechanism.
Any call to Default will cause SCons to use the defined default
target list instead of its built-in algorithm for determining
default targets (see the manpage section "Target Selection").

target may be one or more strings, a list of strings, a NodeList as
returned by a Builder, or None. A string target may be the name of
a file or directory, or a target previously defined by a call to
Alias (defining the alias later will still create the alias, but it
will not be recognized as a default). Calls to Default are
additive. A target of None will clear any existing default target
list; subsequent calls to Default will add to the (now empty)
default target list like normal.

Both forms of this call affect the same global list of default
targets; the construction environment method applies construction
variable expansion to the targets.

The current list of targets added using Default is available in the
DEFAULT_TARGETS list (see below).

Examples:

Default('foo', 'bar', 'baz')
env.Default(['a', 'b', 'c'])
hello = env.Program('hello', 'hello.c')
env.Default(hello)

DefaultEnvironment([**kwargs])
Instantiates and returns the default construction environment
object. The default environment is used internally by SCons in
order to execute many of the global functions in this list (that
is, those not called as methods of a specific construction
environment). It is not mandatory to call DefaultEnvironment: the
default environment will be instantiated automatically when the
build phase begins if the function has not been called, however
calling it explicitly gives the opportunity to affect and examine
the contents of the default environment.

The default environment is a singleton, so the keyword arguments
affect it only on the first call, on subsequent calls the
already-constructed object is returned and any keyword arguments
are silently ignored. The default environment can be modified after
instantiation in the same way as any construction environment.
Modifying the default environment has no effect on the construction
environment constructed by an Environment or Clone call.

Depends(target, dependency), env.Depends(target, dependency)
Specifies an explicit dependency; the target will be rebuilt
whenever the dependency has changed. Both the specified target and
dependency can be a string (usually the path name of a file or
directory) or Node objects, or a list of strings or Node objects
(such as returned by a Builder call). This should only be necessary
for cases where the dependency is not caught by a Scanner for the
file.

Example:

env.Depends('foo', 'other-input-file-for-foo')

mylib = env.Library('mylib.c')
installed_lib = env.Install('lib', mylib)
bar = env.Program('bar.c')

# Arrange for the library to be copied into the installation
# directory before trying to build the "bar" program.
# (Note that this is for example only. A "real" library
# dependency would normally be configured through the $LIBS
# and $LIBPATH variables, not using an env.Depends() call.)

env.Depends(bar, installed_lib)

env.Detect(progs)
Find an executable from one or more choices: progs may be a string
or a list of strings. Returns the first value from progs that was
found, or None. Executable is searched by checking the paths
specified by env['ENV']['PATH']. On Windows systems, additionally
applies the filename suffixes found in env['ENV']['PATHEXT'] but
will not include any such extension in the return value.
env.Detect is a wrapper around env.WhereIs.

env.Dictionary([vars])
Returns a dictionary object containing the construction variables
in the construction environment. If there are any arguments
specified, the values of the specified construction variables are
returned as a string (if one argument) or as a list of strings.

Example:

cvars = env.Dictionary()
cc_values = env.Dictionary('CC', 'CCFLAGS', 'CCCOM')

Dir(name, [directory]), env.Dir(name, [directory])
Returns Directory Node(s). A Directory Node is an object that
represents a directory. name can be a relative or absolute path or
a list of such paths. directory is an optional directory that will
be used as the parent directory. If no directory is specified, the
current script's directory is used as the parent.

If name is a single pathname, the corresponding node is returned.
If name is a list, SCons returns a list of nodes. Construction
variables are expanded in name.

Directory Nodes can be used anywhere you would supply a string as a
directory name to a Builder method or function. Directory Nodes
have attributes and methods that are useful in many situations; see
manpage section "File and Directory Nodes" for more information.

env.Dump([key], [format])
Serializes construction variables to a string. The method supports
the following formats specified by format:

pretty
Returns a pretty printed representation of the environment (if
format is not specified, this is the default).

json
Returns a JSON-formatted string representation of the
environment.

If key is None (the default) the entire dictionary of construction
variables is serialized. If supplied, it is taken as the name of a
construction variable whose value is serialized.

This SConstruct:

env=Environment()
print(env.Dump('CCCOM'))

will print:

'$CC -c -o $TARGET $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $SOURCES'

While this SConstruct:

env = Environment()
print(env.Dump())

will print:

{ 'AR': 'ar',
'ARCOM': '$AR $ARFLAGS $TARGET $SOURCES\n$RANLIB $RANLIBFLAGS $TARGET',
'ARFLAGS': ['r'],
'AS': 'as',
'ASCOM': '$AS $ASFLAGS -o $TARGET $SOURCES',
'ASFLAGS': [],
...

EnsurePythonVersion(major, minor), env.EnsurePythonVersion(major,
minor)
Ensure that the Python version is at least major.minor. This
function will print out an error message and exit SCons with a
non-zero exit code if the actual Python version is not late enough.

Example:

EnsurePythonVersion(2,2)

EnsureSConsVersion(major, minor, [revision]),
env.EnsureSConsVersion(major, minor, [revision])
Ensure that the SCons version is at least major.minor, or
major.minor.revision. if revision is specified. This function will
print out an error message and exit SCons with a non-zero exit code
if the actual SCons version is not late enough.

Examples:

EnsureSConsVersion(0,14)

EnsureSConsVersion(0,96,90)

Environment([key=value, ...]), env.Environment([key=value, ...])
Return a new construction environment initialized with the
specified key=value pairs. The keyword arguments parse_flags,
platform, toolpath, tools and variables are also specially
recognized. See the manpage section "Construction Environments" for
more details.

Execute(action, [strfunction, varlist]), env.Execute(action,
[strfunction, varlist])
Executes an Action object. The specified action may be an Action
object (see manpage section "Action Objects" for an explanation of
behavior), or it may be a command-line string, list of commands, or
executable Python function, each of which will be converted into an
Action object and then executed. Any additional arguments to
Execute (strfunction, varlist) are passed on to the Action factory
function which actually creates the Action object. The exit value
of the command or return value of the Python function will be
returned.

Note that scons will print an error message if the executed action
fails--that is, exits with or returns a non-zero value. scons will
not, however, automatically terminate the build if the specified
action fails. If you want the build to stop in response to a failed
Execute call, you must explicitly check for a non-zero return
value:

Execute(Copy('file.out', 'file.in'))

if Execute("mkdir sub/dir/ectory"):
# The mkdir failed, don't try to build.
Exit(1)

Exit([value]), env.Exit([value])
This tells scons to exit immediately with the specified value. A
default exit value of 0 (zero) is used if no value is specified.

Export([vars...], [key=value...]), env.Export([vars...],
[key=value...])
Exports variables from the current SConscript file to a global
collection where they can be imported by other SConscript files.
vars may be one or more strings representing variable names to be
exported. If a string contains whitespace, it is split into
separate strings, as if multiple string arguments had been given. A
vars argument may also be a dictionary, which can be used to map
variables to different names when exported. Keyword arguments can
be used to provide names and their values.

Export calls are cumulative. Specifying a previously exported
variable will overwrite the earlier value. Both local variables and
global variables can be exported.

Examples:

env = Environment()
# Make env available for all SConscript files to Import().
Export("env")

package = 'my_name'
# Make env and package available for all SConscript files:.
Export("env", "package")

# Make env and package available for all SConscript files:
Export(["env", "package"])

# Make env available using the name debug:
Export(debug=env)

# Make env available using the name debug:
Export({"debug": env})

Note that the SConscript function supports an exports argument that
allows exporting a variable or set of variables to a specific
SConscript file or files. See the description below.

File(name, [directory]), env.File(name, [directory])
Returns File Node(s). A File Node is an object that represents a
file. name can be a relative or absolute path or a list of such
paths. directory is an optional directory that will be used as the
parent directory. If no directory is specified, the current
script's directory is used as the parent.

If name is a single pathname, the corresponding node is returned.
If name is a list, SCons returns a list of nodes. Construction
variables are expanded in name.

File Nodes can be used anywhere you would supply a string as a file
name to a Builder method or function. File Nodes have attributes
and methods that are useful in many situations; see manpage section
"File and Directory Nodes" for more information.

FindFile(file, dirs), env.FindFile(file, dirs)
Search for file in the path specified by dirs. dirs may be a list
of directory names or a single directory name. In addition to
searching for files that exist in the filesystem, this function
also searches for derived files that have not yet been built.

Example:

foo = env.FindFile('foo', ['dir1', 'dir2'])

FindInstalledFiles(), env.FindInstalledFiles()
Returns the list of targets set up by the Install or InstallAs
builders.

This function serves as a convenient method to select the contents
of a binary package.

Example:

Install('/bin', ['executable_a', 'executable_b'])

# will return the file node list
# ['/bin/executable_a', '/bin/executable_b']
FindInstalledFiles()

Install('/lib', ['some_library'])

# will return the file node list
# ['/bin/executable_a', '/bin/executable_b', '/lib/some_library']
FindInstalledFiles()

FindPathDirs(variable)
Returns a function (actually a callable Python object) intended to
be used as the path_function of a Scanner object. The returned
object will look up the specified variable in a construction
environment and treat the construction variable's value as a list
of directory paths that should be searched (like $CPPPATH,
$LIBPATH, etc.).

Note that use of FindPathDirs is generally preferable to writing
your own path_function for the following reasons: 1) The returned
list will contain all appropriate directories found in source trees
(when VariantDir is used) or in code repositories (when Repository
or the -Y option are used). 2) scons will identify expansions of
variable that evaluate to the same list of directories as, in fact,
the same list, and avoid re-scanning the directories for files,
when possible.

Example:

def my_scan(node, env, path, arg):
# Code to scan file contents goes here...
return include_files

scanner = Scanner(name = 'myscanner',
function = my_scan,
path_function = FindPathDirs('MYPATH'))

FindSourceFiles(node='"."'), env.FindSourceFiles(node='"."')
Returns the list of nodes which serve as the source of the built
files. It does so by inspecting the dependency tree starting at the
optional argument node which defaults to the '"."'-node. It will
then return all leaves of node. These are all children which have
no further children.

This function is a convenient method to select the contents of a
Source Package.

Example:

Program('src/main_a.c')
Program('src/main_b.c')
Program('main_c.c')

# returns ['main_c.c', 'src/main_a.c', 'SConstruct', 'src/main_b.c']
FindSourceFiles()

# returns ['src/main_b.c', 'src/main_a.c' ]
FindSourceFiles('src')

As you can see build support files (SConstruct in the above
example) will also be returned by this function.

Flatten(sequence), env.Flatten(sequence)
Takes a sequence (that is, a Python list or tuple) that may contain
nested sequences and returns a flattened list containing all of the
individual elements in any sequence. This can be helpful for
collecting the lists returned by calls to Builders; other Builders
will automatically flatten lists specified as input, but direct
Python manipulation of these lists does not.

Examples:

foo = Object('foo.c')
bar = Object('bar.c')

# Because `foo' and `bar' are lists returned by the Object() Builder,
# `objects' will be a list containing nested lists:
objects = ['f1.o', foo, 'f2.o', bar, 'f3.o']

# Passing such a list to another Builder is all right because
# the Builder will flatten the list automatically:
Program(source = objects)

# If you need to manipulate the list directly using Python, you need to
# call Flatten() yourself, or otherwise handle nested lists:
for object in Flatten(objects):
print(str(object))

GetBuildFailures()
Returns a list of exceptions for the actions that failed while
attempting to build targets. Each element in the returned list is a
BuildError object with the following attributes that record various
aspects of the build failure:

.node The node that was being built when the build failure
occurred.

.status The numeric exit status returned by the command or Python
function that failed when trying to build the specified Node.

.errstr The SCons error string describing the build failure. (This
is often a generic message like "Error 2" to indicate that an
executed command exited with a status of 2.)

.filename The name of the file or directory that actually caused
the failure. This may be different from the .node attribute. For
example, if an attempt to build a target named sub/dir/target fails
because the sub/dir directory could not be created, then the .node
attribute will be sub/dir/target but the .filename attribute will
be sub/dir.

.executor The SCons Executor object for the target Node being
built. This can be used to retrieve the construction environment
used for the failed action.

.action The actual SCons Action object that failed. This will be
one specific action out of the possible list of actions that would
have been executed to build the target.

.command The actual expanded command that was executed and failed,
after expansion of $TARGET, $SOURCE, and other construction
variables.

Note that the GetBuildFailures function will always return an empty
list until any build failure has occurred, which means that
GetBuildFailures will always return an empty list while the
SConscript files are being read. Its primary intended use is for
functions that will be executed before SCons exits by passing them
to the standard Python atexit.register() function. Example:

import atexit

def print_build_failures():
from SCons.Script import GetBuildFailures
for bf in GetBuildFailures():
print("%s failed: %s" % (bf.node, bf.errstr))

atexit.register(print_build_failures)

GetBuildPath(file, [...]), env.GetBuildPath(file, [...])
Returns the scons path name (or names) for the specified file (or
files). The specified file or files may be scons Nodes or strings
representing path names.

GetLaunchDir(), env.GetLaunchDir()
Returns the absolute path name of the directory from which scons
was initially invoked. This can be useful when using the -u, -U or
-D options, which internally change to the directory in which the
SConstruct file is found.

GetOption(name), env.GetOption(name)
This function provides a way to query the value of options which
can be set via the command line or using the SetOption function.

name can be an entry from the following table, which shows the
corresponding command line arguments that could affect the value.
name can be also be the destination variable name from a
project-specific option added using the AddOption function, as long
as the addition happens prior to the GetOption call in the
SConscript files.

Glob(pattern, [ondisk, source, strings, exclude]), env.Glob(pattern,
[ondisk, source, strings, exclude])
Returns Nodes (or strings) that match the specified pattern,
relative to the directory of the current SConscript file. The
evironment method form (env.Glob) performs string substition on
pattern and returns whatever matches the resulting expanded
pattern.

The specified pattern uses Unix shell style metacharacters for
matching:

* matches everything
? matches any single character
[seq] matches any character in seq
[!seq] matches any char not in seq

If the first character of a filename is a dot, it must be matched
explicitly. Character matches do not span directory separators.

The Glob knows about repositories (see the Repository function) and
source directories (see the VariantDir function) and returns a Node
(or string, if so configured) in the local (SConscript) directory
if a matching Node is found anywhere in a corresponding repository
or source directory.

The ondisk argument may be set to a value which evaluates False to
disable the search for matches on disk, thereby only returning
matches among already-configured File or Dir Nodes. The default
behavior is to return corresponding Nodes for any on-disk matches
found.

The source argument may be set to a value which evaluates True to
specify that, when the local directory is a VariantDir, the
returned Nodes should be from the corresponding source directory,
not the local directory.

The strings argument may be set to a value which evaluates True to
have the Glob function return strings, not Nodes, that represent
the matched files or directories. The returned strings will be
relative to the local (SConscript) directory. (Note that This may
make it easier to perform arbitrary manipulation of file names, but
if the returned strings are passed to a different SConscript file,
any Node translation will be relative to the other SConscript
directory, not the original SConscript directory.)

The exclude argument may be set to a pattern or a list of patterns
(following the same Unix shell semantics) which must be filtered
out of returned elements. Elements matching a least one pattern of
this list will be excluded.

Examples:

Program("foo", Glob("*.c"))
Zip("/tmp/everything", Glob(".??*") + Glob("*"))
sources = Glob("*.cpp", exclude=["os_*_specific_*.cpp"]) + \
Glob( "os_%s_specific_*.cpp" % currentOS)

Help(text, append=False), env.Help(text, append=False)
Specifies a local help message to be printed if the -h argument is
given to scons. Subsequent calls to Help append text to the
previously defined local help text.

For the first call to Help only, if append is False (the default)
any local help message generated through AddOption calls is
replaced. If append is True, text is appended to the existing help
text.

Ignore(target, dependency), env.Ignore(target, dependency)
The specified dependency file(s) will be ignored when deciding if
the target file(s) need to be rebuilt.

You can also use Ignore to remove a target from the default build.
In order to do this you must specify the directory the target will
be built in as the target, and the file you want to skip building
as the dependency.

Note that this will only remove the dependencies listed from the
files built by default. It will still be built if that dependency
is needed by another object being built. See the third and forth
examples below.

Examples:

env.Ignore('foo', 'foo.c')
env.Ignore('bar', ['bar1.h', 'bar2.h'])
env.Ignore('.', 'foobar.obj')
env.Ignore('bar', 'bar/foobar.obj')

Import(vars...), env.Import(vars...)
Imports variables into the current SConscript file. vars must be
strings representing names of variables which have been previously
exported either by the Export function or by the exports argument
to SConscript. Variables exported by SConscript take precedence.
Multiple variable names can be passed to Import as separate
arguments or as words in a space-separated string. The wildcard "*"
can be used to import all available variables.

Examples:

Import("env")
Import("env", "variable")
Import(["env", "variable"])
Import("*")

Literal(string), env.Literal(string)
The specified string will be preserved as-is and not have
construction variables expanded.

Local(targets), env.Local(targets)
The specified targets will have copies made in the local tree, even
if an already up-to-date copy exists in a repository. Returns a
list of the target Node or Nodes.

env.MergeFlags(arg, [unique])
Merges values from arg into construction variables in the current
construction environment. If arg is not a dictionary, it is
converted to one by calling env.ParseFlags on the argument before
the values are merged. Note that arg must be a single value, so
multiple strings must be passed in as a list, not as separate
arguments to env.MergeFlags.

By default, duplicate values are eliminated; you can, however,
specify unique=False to allow duplicate values to be added. When
eliminating duplicate values, any construction variables that end
with the string PATH keep the left-most unique value. All other
construction variables keep the right-most unique value.

Examples:

# Add an optimization flag to $CCFLAGS.
env.MergeFlags('-O3')

# Combine the flags returned from running pkg-config with an optimization
# flag and merge the result into the construction variables.
env.MergeFlags(['!pkg-config gtk+-2.0 --cflags', '-O3'])

# Combine an optimization flag with the flags returned from running pkg-config
# twice and merge the result into the construction variables.
env.MergeFlags(['-O3',
'!pkg-config gtk+-2.0 --cflags --libs',
'!pkg-config libpng12 --cflags --libs'])

NoCache(target, ...), env.NoCache(target, ...)
Specifies a list of files which should not be cached whenever the
CacheDir method has been activated. The specified targets may be a
list or an individual target.

Multiple files should be specified either as separate arguments to
the NoCache method, or as a list. NoCache will also accept the
return value of any of the construction environment Builder
methods.

Calling NoCache on directories and other non-File Node types has no
effect because only File Nodes are cached.

Examples:

NoCache('foo.elf')
NoCache(env.Program('hello', 'hello.c'))

NoClean(target, ...), env.NoClean(target, ...)
Specifies a list of files or directories which should not be
removed whenever the targets (or their dependencies) are specified
with the -c command line option. The specified targets may be a
list or an individual target. Multiple calls to NoClean are legal,
and prevent each specified target from being removed by calls to
the -c option.

Multiple files or directories should be specified either as
separate arguments to the NoClean method, or as a list. NoClean
will also accept the return value of any of the construction
environment Builder methods.

Calling NoClean for a target overrides calling Clean for the same
target, and any targets passed to both functions will not be
removed by the -c option.

Examples:

NoClean('foo.elf')
NoClean(env.Program('hello', 'hello.c'))

env.ParseConfig(command, [function, unique])
Updates the current construction environment with the values
extracted from the output from running external command, by calling
a helper function function which understands the output of command.
command may be a string or a list of strings representing the
command and its arguments. If function is not given, env.MergeFlags
is used. By default, duplicate values are not added to any
construction variables; you can specify unique=False to allow
duplicate values to be added.

If env.MergeFlags is used, it expects a response in the style of a
*-config command typical of the POSIX programming environment (for
example, gtk-config) and adds the options to the appropriate
construction variables. Interpreted options and the construction
variables they affect are as specified for the env.ParseFlags
method (which env.MergeFlags calls). See that method's description
for a table of options and corresponding construction variables.

If env.MergeFlags cannot interpret the results of command, you can
suppply a custom function to do so. function must accept three
arguments: the construction environment to modify, the string
returned by running command, and the optional unique flag.

ParseDepends(filename, [must_exist, only_one]),
env.ParseDepends(filename, [must_exist, only_one])
Parses the contents of the specified filename as a list of
dependencies in the style of Make or mkdep, and explicitly
establishes all of the listed dependencies.

By default, it is not an error if the specified filename does not
exist. The optional must_exist argument may be set to a non-zero
value to have scons throw an exception and generate an error if the
file does not exist, or is otherwise inaccessible.

The optional only_one argument may be set to a non-zero value to
have scons thrown an exception and generate an error if the file
contains dependency information for more than one target. This can
provide a small sanity check for files intended to be generated by,
for example, the gcc -M flag, which should typically only write
dependency information for one output file into a corresponding .d
file.

The filename and all of the files listed therein will be
interpreted relative to the directory of the SConscript file which
calls the ParseDepends function.

env.ParseFlags(flags, ...)
Parses one or more strings containing typical command-line flags
for GCC tool chains and returns a dictionary with the flag values
separated into the appropriate SCons construction variables. This
is intended as a companion to the env.MergeFlags method, but allows
for the values in the returned dictionary to be modified, if
necessary, before merging them into the construction environment.
(Note that env.MergeFlags will call this method if its argument is
not a dictionary, so it is usually not necessary to call
env.ParseFlags directly unless you want to manipulate the values.)

If the first character in any string is an exclamation mark (!),
the rest of the string is executed as a command, and the output
from the command is parsed as GCC tool chain command-line flags and
added to the resulting dictionary.

Flag values are translated accordig to the prefix found, and added
to the following construction variables:

-arch CCFLAGS, LINKFLAGS
-D CPPDEFINES
-framework FRAMEWORKS
-frameworkdir= FRAMEWORKPATH
-fmerge-all-constants CCFLAGS, LINKFLAGS
-fopenmp CCFLAGS, LINKFLAGS
-include CCFLAGS
-imacros CCFLAGS
-isysroot CCFLAGS, LINKFLAGS
-isystem CCFLAGS
-iquote CCFLAGS
-idirafter CCFLAGS
-I CPPPATH
-l LIBS
-L LIBPATH
-mno-cygwin CCFLAGS, LINKFLAGS
-mwindows LINKFLAGS
-openmp CCFLAGS, LINKFLAGS
-pthread CCFLAGS, LINKFLAGS
-std= CFLAGS
-Wa, ASFLAGS, CCFLAGS
-Wl,-rpath= RPATH
-Wl,-R, RPATH
-Wl,-R RPATH
-Wl, LINKFLAGS
-Wp, CPPFLAGS
- CCFLAGS
+ CCFLAGS, LINKFLAGS

Any other strings not associated with options are assumed to be the
names of libraries and added to the $LIBS construction variable.

Examples (all of which produce the same result):

dict = env.ParseFlags('-O2 -Dfoo -Dbar=1')
dict = env.ParseFlags('-O2', '-Dfoo', '-Dbar=1')
dict = env.ParseFlags(['-O2', '-Dfoo -Dbar=1'])
dict = env.ParseFlags('-O2', '!echo -Dfoo -Dbar=1')

Platform(string)
The Platform form returns a callable object that can be used to
initialize a construction environment using the platform keyword of
the Environment function.

Example:

env = Environment(platform=Platform('win32'))

The env.Platform form applies the callable object for the specified
platform string to the environment through which the method was
called.

env.Platform('posix')

Note that the win32 platform adds the SystemDrive and SystemRoot
variables from the user's external environment to the construction
environment's $ENV dictionary. This is so that any executed
commands that use sockets to connect with other systems (such as
fetching source files from external CVS repository specifications
like :pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons) will
work on Windows systems.

Precious(target, ...), env.Precious(target, ...)
Marks each given target as precious so it is not deleted before it
is rebuilt. Normally scons deletes a target before building it.
Multiple targets can be passed in to a single call to Precious.

env.Prepend(key=val, [...])
Prepend values to construction variables in the current
construction environment, Works like env.Append (see for details),
except that values are added to the front, rather than the end, of
any existing value of the construction variable

Example:

env.Prepend(CCFLAGS='-g ', FOO=['foo.yyy'])

See also env.Append, env.AppendUnique and env.PrependUnique.

env.PrependENVPath(name, newpath, [envname, sep, delete_existing])
Prepend new path elements to the given path in the specified
external environment ($ENV by default). This will only add any
particular path once (leaving the first one it encounters and
ignoring the rest, to preserve path order), and to help assure
this, will normalize all paths (using os.path.normpath and
os.path.normcase). This can also handle the case where the given
old path variable is a list instead of a string, in which case a
list will be returned instead of a string.

If delete_existing is False, then adding a path that already exists
will not move it to the beginning; it will stay where it is in the
list.

Example:

print('before:', env['ENV']['INCLUDE'])
include_path = '/foo/bar:/foo'
env.PrependENVPath('INCLUDE', include_path)
print('after:', env['ENV']['INCLUDE'])

Yields:

before: /biz:/foo
after: /foo/bar:/foo:/biz

env.PrependUnique(key=val, delete_existing=False, [...])
Prepend values to construction variables in the current
construction environment, maintaining uniqueness. Works like
env.Append (see for details), except that values are added to the
front, rather than the end, of any existing value of the the
construction variable, and values already present in the
construction variable will not be added again. If delete_existing
is True, the existing matching value is first removed, and the
requested value is inserted, having the effect of moving such
values to the front.

Example:

env.PrependUnique(CCFLAGS='-g', FOO=['foo.yyy'])

See also env.Append, env.AppendUnique and env.Prepend.

Progress(callable, [interval]), Progress(string, [interval, file,
overwrite]), Progress(list_of_strings, [interval, file, overwrite])
Allows SCons to show progress made during the build by displaying a
string or calling a function while evaluating Nodes (e.g. files).

If the first specified argument is a Python callable (a function or
an object that has a __call__ method), the function will be called
once every interval times a Node is evaluated (default 1). The
callable will be passed the evaluated Node as its only argument.
(For future compatibility, it's a good idea to also add *args and
**kwargs as arguments to your function or method signatures. This
will prevent the code from breaking if SCons ever changes the
interface to call the function with additional arguments in the
future.)

An example of a simple custom progress function that prints a
string containing the Node name every 10 Nodes:

def my_progress_function(node, *args, **kwargs):
print('Evaluating node %s!' % node)
Progress(my_progress_function, interval=10)

A more complicated example of a custom progress display object that
prints a string containing a count every 100 evaluated Nodes. Note
the use of \r (a carriage return) at the end so that the string
will overwrite itself on a display:

import sys
class ProgressCounter(object):
count = 0
def __call__(self, node, *args, **kw):
self.count += 100
sys.stderr.write('Evaluated %s nodes\r' % self.count)

Progress(ProgressCounter(), interval=100)

If the first argument to Progress is a string or list of strings,
it is taken as text to be displayed every interval evaluated Nodes.
If the first argument is a list of strings, then each string in the
list will be displayed in rotating fashion every interval evaluated
Nodes.

The default is to print the string on standard output. An alternate
output stream may be specified with the file keyword argument,
which the caller must pass already opened.

The following will print a series of dots on the error output, one
dot for every 100 evaluated Nodes:

import sys
Progress('.', interval=100, file=sys.stderr)

If the string contains the verbatim substring $TARGET;, it will be
replaced with the Node. Note that, for performance reasons, this is
not a regular SCons variable substition, so you can not use other
variables or use curly braces. The following example will print the
name of every evaluated Node, using a carriage return) (\r) to
cause each line to overwritten by the next line, and the overwrite
keyword argument (default False) to make sure the
previously-printed file name is overwritten with blank spaces:

import sys
Progress('$TARGET\r', overwrite=True)

A list of strings can be used to implement a "spinner" on the
user's screen as follows, changing every five evaluated Nodes:

Progress(['-\r', '\\\r', '|\r', '/\r'], interval=5)

Pseudo(target, ...), env.Pseudo(target, ...)
This indicates that each given target should not be created by the
build rule, and if the target is created, an error will be
generated. This is similar to the gnu make .PHONY target. However,
in the vast majority of cases, an Alias is more appropriate.
Multiple targets can be passed in to a single call to Pseudo.

PyPackageDir(modulename), env.PyPackageDir(modulename)
This returns a Directory Node similar to Dir. The python module /
package is looked up and if located the directory is returned for
the location. modulename Is a named python package / module to
lookup the directory for it's location.

If modulename is a list, SCons returns a list of Dir nodes.
Construction variables are expanded in modulename.

env.Replace(key=val, [...])
Replaces construction variables in the Environment with the
specified keyword arguments.

Example:

env.Replace(CCFLAGS='-g', FOO='foo.xxx')

Repository(directory), env.Repository(directory)
Specifies that directory is a repository to be searched for files.
Multiple calls to Repository are legal, and each one adds to the
list of repositories that will be searched.

To scons, a repository is a copy of the source tree, from the
top-level directory on down, which may contain both source files
and derived files that can be used to build targets in the local
source tree. The canonical example would be an official source tree
maintained by an integrator. If the repository contains derived
files, then the derived files should have been built using scons,
so that the repository contains the necessary signature information
to allow scons to figure out when it is appropriate to use the
repository copy of a derived file, instead of building one locally.

Note that if an up-to-date derived file already exists in a
repository, scons will not make a copy in the local directory tree.
In order to guarantee that a local copy will be made, use the Local
method.

Requires(target, prerequisite), env.Requires(target, prerequisite)
Specifies an order-only relationship between the specified target
file(s) and the specified prerequisite file(s). The prerequisite
file(s) will be (re)built, if necessary, before the target file(s),
but the target file(s) do not actually depend on the prerequisites
and will not be rebuilt simply because the prerequisite file(s)
change.

Example:

env.Requires('foo', 'file-that-must-be-built-before-foo')

Return([vars..., stop=True])
Return to the calling SConscript, optionally returning the values
of variables named in vars. Multiple strings contaning variable
names may be passed to Return. A string containing white space is
split into individual variable names. Returns the value if one
variable is specified, else returns a tuple of values. Returns an
empty tuple if vars is omitted.

By default Return stops processing the current SConscript and
returns immediately. The optional stop keyword argument may be set
to a false value to continue processing the rest of the SConscript
file after the Return call (this was the default behavior prior to
SCons 0.98.) However, the values returned are still the values of
the variables in the named vars at the point Return was called.

Examples:

# Returns no values (evaluates False)
Return()

# Returns the value of the 'foo' Python variable.
Return("foo")

# Returns the values of the Python variables 'foo' and 'bar'.
Return("foo", "bar")

# Returns the values of Python variables 'val1' and 'val2'.
Return('val1 val2')

Scanner(function, [name, argument, skeys, path_function, node_class,
node_factory, scan_check, recursive]), env.Scanner(function, [name,
argument, skeys, path_function, node_class, node_factory, scan_check,
recursive])
Creates a Scanner object for the specified function. See manpage
section "Scanner Objects" for a complete explanation of the
arguments and behavior.

SConscript(scripts, [exports, variant_dir, duplicate, must_exist]),
env.SConscript(scripts, [exports, variant_dir, duplicate, must_exist]),
SConscript(dirs=subdirs, [name=script, exports, variant_dir, duplicate,
must_exist]), env.SConscript(dirs=subdirs, [name=script, exports,
variant_dir, duplicate, must_exist])
Execute one or more subsidiary SConscript (configuration) files.
There are two ways to call the SConscript function.

The first calling style is to explicitly specify one or more
scripts as the first argument. A single script may be specified as
a string; multiple scripts must be specified as a list (either
explicitly or as created by a function like Split). Examples:

SConscript('SConscript') # run SConscript in the current directory
SConscript('src/SConscript') # run SConscript in the src directory
SConscript(['src/SConscript', 'doc/SConscript'])
config = SConscript('MyConfig.py')

The second way to call SConscript is to specify a list of
(sub)directory names as a dirs=subdirs keyword argument. In this
case, scons will execute a subsidiary configuration file named
SConscript in each of the specified directories. You may specify a
name other than SConscript by supplying an optional name=script
keyword argument. The first three examples below have the same
effect as the first three examples above:

SConscript(dirs='.') # run SConscript in the current directory
SConscript(dirs='src') # run SConscript in the src directory
SConscript(dirs=['src', 'doc'])
SConscript(dirs=['sub1', 'sub2'], name='MySConscript')

The optional exports argument provides a string or list of strings
representing variable names, or a dictionary of named values, to
export. These variables are locally exported only to the called
SConscript file(s) and do not affect the global pool of variables
managed by the Export function. The subsidiary SConscript files
must use the Import function to import the variables. Examples:

foo = SConscript('sub/SConscript', exports='env')
SConscript('dir/SConscript', exports=['env', 'variable'])
SConscript(dirs='subdir', exports='env variable')
SConscript(dirs=['one', 'two', 'three'], exports='shared_info')

If the optional variant_dir argument is present, it causes an
effect equivalent to the VariantDir function. The variant_dir
argument is interpreted relative to the directory of the calling
SConscript file. The optional duplicate argument is interpreted as
for VariantDir. If variant_dir is omitted, the duplicate argument
is ignored. See the description of VariantDir below for additional
details and restrictions.

If variant_dir is present, the source directory is the directory in
which the SConscript file resides and the SConscript file is
evaluated as if it were in the variant_dir directory:

SConscript('src/SConscript', variant_dir='build')

is equivalent to

VariantDir('build', 'src')
SConscript('build/SConscript')

This later paradigm is often used when the sources are in the same
directory as the SConstruct:

SConscript('SConscript', variant_dir='build')

is equivalent to

VariantDir('build', '.')
SConscript('build/SConscript')

If the optional must_exist is True, causes an exception to be
raised if a requested SConscript file is not found. The current
default is False, causing only a warning to be emitted, but this
default is deprecated (since 3.1). For scripts which truly intend
to be optional, transition to explicitly supplying must_exist=False
to the SConscript call.

Here are some composite examples:

# collect the configuration information and use it to build src and doc
shared_info = SConscript('MyConfig.py')
SConscript('src/SConscript', exports='shared_info')
SConscript('doc/SConscript', exports='shared_info')

# build debugging and production versions. SConscript
# can use Dir('.').path to determine variant.
SConscript('SConscript', variant_dir='debug', duplicate=0)
SConscript('SConscript', variant_dir='prod', duplicate=0)

# build debugging and production versions. SConscript
# is passed flags to use.
opts = { 'CPPDEFINES' : ['DEBUG'], 'CCFLAGS' : '-pgdb' }
SConscript('SConscript', variant_dir='debug', duplicate=0, exports=opts)
opts = { 'CPPDEFINES' : ['NODEBUG'], 'CCFLAGS' : '-O' }
SConscript('SConscript', variant_dir='prod', duplicate=0, exports=opts)

# build common documentation and compile for different architectures
SConscript('doc/SConscript', variant_dir='build/doc', duplicate=0)
SConscript('src/SConscript', variant_dir='build/x86', duplicate=0)
SConscript('src/SConscript', variant_dir='build/ppc', duplicate=0)

SConscript returns the values of any variables named by the
executed SConscript(s) in arguments to the Return function (see
above for details). If a single SConscript call causes multiple
scripts to be executed, the return value is a tuple containing the
returns of all of the scripts. If an executed script does not
explicitly call Return, it returns None.

SConscriptChdir(value), env.SConscriptChdir(value)
By default, scons changes its working directory to the directory in
which each subsidiary SConscript file lives. This behavior may be
disabled by specifying either:

SConscriptChdir(0)
env.SConscriptChdir(0)

in which case scons will stay in the top-level directory while
reading all SConscript files. (This may be necessary when building
from repositories, when all the directories in which SConscript
files may be found don't necessarily exist locally.) You may enable
and disable this ability by calling SConscriptChdir() multiple
times.

Example:

env = Environment()
SConscriptChdir(0)
SConscript('foo/SConscript') # will not chdir to foo
env.SConscriptChdir(1)
SConscript('bar/SConscript') # will chdir to bar

SConsignFile([name, dbm_module]), env.SConsignFile([name, dbm_module])
Specify where to store the SCons file signature database, and which
database format to use. This may be useful to specify alternate
database files and/or file locations for different types of builds.

The optional name argument is the base name of the database
file(s). If not an absolute path name, these are placed relative to
the directory containing the top-level SConstruct file. The default
is .sconsign. The actual database file(s) stored on disk may have
an appropriate suffix appended by the chosen dbm_module

The optional dbm_module argument specifies which Python database
module to use for reading/writing the file. The module must be
imported first; then the imported module name is passed as the
argument. The default is a custom SCons.dblite module that uses
pickled Python data structures, which works on all Python versions.
See documentation of the Python dbm module for other available
types.

If called with no arguments, the database will default to
.sconsign.dblite in the top directory of the project, which is also
the default if if SConsignFile is not called.

The setting is global, so the only difference between the global
function and the environment method form is variable expansion on
name. There should only be one active call to this function/method
in a given build setup.

If name is set to None, scons will store file signatures in a
separate .sconsign file in each directory, not in a single combined
database file. This is a backwards-compatibility meaure to support
what was the default behavior prior to SCons 0.97 (i.e. before
2008). Use of this mode is discouraged and may be deprecated in a
future SCons release.

Examples:

# Explicitly stores signatures in ".sconsign.dblite"
# in the top-level SConstruct directory (the default behavior).
SConsignFile()

# Stores signatures in the file "etc/scons-signatures"
# relative to the top-level SConstruct directory.
# SCons will add a database suffix to this name.
SConsignFile("etc/scons-signatures")

# Stores signatures in the specified absolute file name.
# SCons will add a database suffix to this name.
SConsignFile("/home/me/SCons/signatures")

# Stores signatures in a separate .sconsign file
# in each directory.
SConsignFile(None)

# Stores signatures in a GNU dbm format .sconsign file
import dbm.gnu
SConsignFile(dbm_module=dbm.gnu)

env.SetDefault(key=val, [...])
Sets construction variables to default values specified with the
keyword arguments if (and only if) the variables are not already
set. The following statements are equivalent:

env.SetDefault(FOO='foo')
if 'FOO' not in env:
env['FOO'] = 'foo'

SetOption(name, value), env.SetOption(name, value)
Sets scons option variable name to value. These options are all
also settable via command-line options but the variable name may
differ from the command-line option name - see the table for
correspondences. A value set via command-line option will take
precedence over one set with SetOption, which allows setting a
project default in the scripts and temporarily overriding it via
command line. SetOption calls can also be placed in the
site_init.py file.

See the documentation in the manpage for the corresponding command
line option for information about each specific option. The value
parameter is mandatory, for option values which are boolean in
nature (that is, the command line option does not take an argument)
use a value which evaluates to true (e.g. True, 1) or false (e.g.
False, 0).

Options which affect the reading and processing of SConscript files
are not settable using SetOption since those files must be read in
order to find the SetOption call in the first place.

The settable variables with their associated command-line options
are:

SetOption('max_drift', 0)

SideEffect(side_effect, target), env.SideEffect(side_effect, target)
Declares side_effect as a side effect of building target. Both
side_effect and target can be a list, a file name, or a node. A
side effect is a target file that is created or updated as a side
effect of building other targets. For example, a Windows PDB file
is created as a side effect of building the .obj files for a static
library, and various log files are created updated as side effects
of various TeX commands. If a target is a side effect of multiple
build commands, scons will ensure that only one set of commands is
executed at a time. Consequently, you only need to use this method
for side-effect targets that are built as a result of multiple
build commands.

Because multiple build commands may update the same side effect
file, by default the side_effect target is not automatically
removed when the target is removed by the -c option. (Note,
however, that the side_effect might be removed as part of cleaning
the directory in which it lives.) If you want to make sure the
side_effect is cleaned whenever a specific target is cleaned, you
must specify this explicitly with the Clean or env.Clean function.

This function returns the list of side effect Node objects that
were successfully added. If the list of side effects contained any
side effects that had already been added, they are not added and
included in the returned list.

Split(arg), env.Split(arg)
Returns a list of file names or other objects. If arg is a string,
it will be split on strings of white-space characters within the
string, making it easier to write long lists of file names. If arg
is already a list, the list will be returned untouched. If arg is
any other type of object, it will be returned as a list containing
just the object.

Example:

files = Split("f1.c f2.c f3.c")
files = env.Split("f4.c f5.c f6.c")
files = Split("""
f7.c
f8.c
f9.c
""")

env.subst(input, [raw, target, source, conv])
Performs construction variable interpolation on the specified
string or sequence argument input.

By default, leading or trailing white space will be removed from
the result. and all sequences of white space will be compressed to
a single space character. Additionally, any $( and $) character
sequences will be stripped from the returned string, The optional
raw argument may be set to 1 if you want to preserve white space
and $(-$) sequences. The raw argument may be set to 2 if you want
to strip all characters between any $( and $) pairs (as is done for
signature calculation).

If the input is a sequence (list or tuple), the individual elements
of the sequence will be expanded, and the results will be returned
as a list.

The optional target and source keyword arguments must be set to
lists of target and source nodes, respectively, if you want the
$TARGET, $TARGETS, $SOURCE and $SOURCES to be available for
expansion. This is usually necessary if you are calling env.subst
from within a Python function used as an SCons action.

Returned string values or sequence elements are converted to their
string representation by default. The optional conv argument may
specify a conversion function that will be used in place of the
default. For example, if you want Python objects (including SCons
Nodes) to be returned as Python objects, you can use the Python
idiom to pass in an unnamed function that simply returns its
unconverted argument.

Example:

print(env.subst("The C compiler is: $CC"))

def compile(target, source, env):
sourceDir = env.subst(
"${SOURCE.srcdir}",
target=target,
source=source
)

source_nodes = env.subst('$EXPAND_TO_NODELIST', conv=lambda x: x)

Tag(node, tags)
Annotates file or directory Nodes with information about how the
Package Builder should package those files or directories. All
Node-level tags are optional.

Examples:

# makes sure the built library will be installed with 644 file access mode
Tag(Library('lib.c'), UNIX_ATTR="0o644")

# marks file2.txt to be a documentation file
Tag('file2.txt', DOC)

Tool(name, [toolpath, **kwargs]), env.Tool(name, [toolpath, **kwargs])
Locates the tool specification module name and returns a callable
tool object for that tool. The tool module is searched for in
standard locations and in any paths specified by the optional
toolpath parameter. The standard locations are SCons' own internal
path for tools plus the toolpath, if any (see the Tools section in
the manual page for more details). Any additional keyword arguments
kwargs are passed to the tool module's generate function during
tool object construction.

When called, the tool object updates a construction environment
with construction variables and arranges any other initialization
needed to use the mechanisms that tool describes.

When the env.Tool form is used, the tool object is automatically
called to update env and the value of tool is appended to the
$TOOLS construction variable in that environment.

Examples:

env.Tool('gcc')
env.Tool('opengl', toolpath=['build/tools'])

When the global function Tool form is used, the tool object is
constructed but not called, as it lacks the context of an
environment to update. The tool object can be passed to an
Environment or Clone call as part of the tools keyword argument, in
which case the tool is applied to the environment being
constructed, or it can be called directly, in which case a
construction environment to update must be passed as the argument.
Either approach will also update the $TOOLS construction variable.

Examples:

env = Environment(tools=[Tool('msvc')])

env = Environment()
msvctool = Tool('msvc')
msvctool(env) # adds 'msvc' to the TOOLS variable
gltool = Tool('opengl', toolpath = ['tools'])
gltool(env) # adds 'opengl' to the TOOLS variable

Changed in SCons 4.2: env.Tool now returns the tool object,
previously it did not return (i.e. returned None).

Value(value, [built_value], [name]), env.Value(value, [built_value],
[name])
Returns a Node object representing the specified Python value.
Value Nodes can be used as dependencies of targets. If the result
of calling str(value) changes between SCons runs, any targets
depending on Value(value) will be rebuilt. (This is true even when
using timestamps to decide if files are up-to-date.) When using
timestamp source signatures, Value Nodes' timestamps are equal to
the system time when the Node is created. name can be provided as
an alternative name for the resulting Value node; this is advised
if the value parameter can't be converted to a string.

The returned Value Node object has a write() method that can be
used to "build" a Value Node by setting a new value. The optional
built_value argument can be specified when the Value Node is
created to indicate the Node should already be considered "built."
There is a corresponding read() method that will return the built
value of the Node.

Examples:

env = Environment()

def create(target, source, env):
# A function that will write a 'prefix=$SOURCE'
# string into the file name specified as the
# $TARGET.
with open(str(target[0]), 'wb') as f:
f.write('prefix=' + source[0].get_contents())

# Fetch the prefix= argument, if any, from the command
# line, and use /usr/local as the default.
prefix = ARGUMENTS.get('prefix', '/usr/local')

# Attach a .Config() builder for the above function action
# to the construction environment.
env['BUILDERS']['Config'] = Builder(action = create)
env.Config(target = 'package-config', source = Value(prefix))

def build_value(target, source, env):
# A function that "builds" a Python Value by updating
# the the Python value with the contents of the file
# specified as the source of the Builder call ($SOURCE).
target[0].write(source[0].get_contents())

output = env.Value('before')
input = env.Value('after')

# Attach a .UpdateValue() builder for the above function
# action to the construction environment.
env['BUILDERS']['UpdateValue'] = Builder(action = build_value)
env.UpdateValue(target = Value(output), source = Value(input))

VariantDir(variant_dir, src_dir, [duplicate]),
env.VariantDir(variant_dir, src_dir, [duplicate])
Sets up an alternate build location. When building in the
variant_dir, SCons backfills as needed with files from src_dir to
create a complete build directory. VariantDir can be called
multiple times with the same src_dir to set up multiple builds with
different options (variants).

The variant location must be in or underneath the project top
directory, and src_dir may not be underneath variant_dir.

By default, SCons physically duplicates the source files and
SConscript files as needed into the variant tree. Thus, a build
performed in the variant tree is guaranteed to be identical to a
build performed in the source tree even if intermediate source
files are generated during the build, or if preprocessors or other
scanners search for included files relative to the source file, or
if individual compilers or other invoked tools are hard-coded to
put derived files in the same directory as source files. Only the
files SCons calculates are needed for the build are duplicated into
variant_dir.

If possible on the platform, the duplication is performed by
linking rather than copying. This behavior is affected by the
--duplicate command-line option.

Duplicating the source files may be disabled by setting the
duplicate argument to False. This will cause SCons to invoke
Builders using the path names of source files in src_dir and the
path names of derived files within variant_dir. This is more
efficient than duplicate=True, and is safe for most builds; revert
to True if it causes problems.

VariantDir works most naturally with used with a subsidiary
SConscript file. The subsidiary SConscript file is called as if it
were in variant_dir, regardless of the value of duplicate. This is
how you tell scons which variant of a source tree to build:

# run src/SConscript in two variant directories
VariantDir('build/variant1', 'src')
SConscript('build/variant1/SConscript')
VariantDir('build/variant2', 'src')
SConscript('build/variant2/SConscript')

See also the SConscript function, described above, for another way
to specify a variant directory in conjunction with calling a
subsidiary SConscript file.

Examples:

# use names in the build directory, not the source directory
VariantDir('build', 'src', duplicate=0)
Program('build/prog', 'build/source.c')

# this builds both the source and docs in a separate subtree
VariantDir('build', '.', duplicate=0)
SConscript(dirs=['build/src','build/doc'])

# same as previous example, but only uses SConscript
SConscript(dirs='src', variant_dir='build/src', duplicate=0)
SConscript(dirs='doc', variant_dir='build/doc', duplicate=0)

WhereIs(program, [path, pathext, reject]), env.WhereIs(program, [path,
pathext, reject])
Searches for the specified executable program, returning the full
path to the program or None.

When called as a construction environment method, searches the
paths in the path keyword argument, or if None (the default) the
paths listed in the construction environment (env['ENV']['PATH']).
The external environment's path list (os.environ['PATH']) is used
as a fallback if the key env['ENV']['PATH'] does not exist.

On Windows systems, searches for executable programs with any of
the file extensions listed in the pathext keyword argument, or if
None (the default) the pathname extensions listed in the
construction environment (env['ENV']['PATHEXT']). The external
environment's pathname extensions list (os.environ['PATHEXT']) is
used as a fallback if the key env['ENV']['PATHEXT'] does not exist.

When called as a global function, uses the external environment's
path os.environ['PATH'] and path extensions os.environ['PATHEXT'],
respectively, if path and pathext are None.

Will not select any path name or names in the optional reject list.

SConscript Variables
In addition to the global functions and methods, scons supports a
number of variables that can be used in SConscript files to affect how
you want the build to be performed.

ARGLIST
A list of the keyword=value arguments specified on the command
line. Each element in the list is a tuple containing the argument.
The separate keyword and value elements of the tuple can be
accessed by subscripting for elements [0] and [1] of the tuple, or,
more readably, by using tuple unpacking. Example:

print("first keyword, value =", ARGLIST[0][0], ARGLIST[0][1])
print("second keyword, value =", ARGLIST[1][0], ARGLIST[1][1])
key, value = ARGLIST[2]
print("third keyword, value =", key, value)
for key, value in ARGLIST:
# process key and value

ARGUMENTS
A dictionary of all the keyword=value arguments specified on the
command line. The dictionary is not in order, and if a given
keyword has more than one value assigned to it on the command line,
the last (right-most) value is the one in the ARGUMENTS dictionary.

Example:

if ARGUMENTS.get('debug', 0):
env = Environment(CCFLAGS='-g')
else:
env = Environment()

BUILD_TARGETS
A list of the targets which scons has been asked to build. The
contents will be either those targets listed on the command line,
or, if none, those targets set via calls to the Default function.
It does not contain any dependent targets that scons selects for
building as a result of making the sure the specified targets are
up to date, if those targets did not appear on the command line.
The list is empty if neither command line targets or Default calls
are present.

The elements of this list may be strings or nodes, so you should
run the list through the Python str function to make sure any Node
path names are converted to strings.

Because this list may be taken from the list of targets specified
using the Default function, the contents of the list may change on
each successive call to Default. See the DEFAULT_TARGETS list,
below, for additional information.

Example:

if 'foo' in BUILD_TARGETS:
print("Don't forget to test the `foo' program!")
if 'special/program' in BUILD_TARGETS:
SConscript('special')

COMMAND_LINE_TARGETS
A list of the targets explicitly specified on the command line. If
there are command line targets, this list will have the same
contents as BUILD_TARGETS. If there are no targets specified on the
command line, the list is empty. The elements of this list are
strings. This can be used, for example, to take specific actions
only when certain targets are explicitly being built.

Example:

if 'foo' in COMMAND_LINE_TARGETS:
print("Don't forget to test the `foo' program!")
if 'special/program' in COMMAND_LINE_TARGETS:
SConscript('special')

DEFAULT_TARGETS
A list of the target nodes that have been specified using the
Default function. If there are no command line targets, this list
will have the same contents as BUILD_TARGETS. Since the elements of
the list are nodes, you need to call the Python str function on
them to get the path name for each Node.

Example:

print(str(DEFAULT_TARGETS[0]))
if 'foo' in [str(t) for t in DEFAULT_TARGETS]:
print("Don't forget to test the `foo' program!")

The contents of the DEFAULT_TARGETS list change on on each
successive call to the Default function:

print([str(t) for t in DEFAULT_TARGETS]) # originally []
Default('foo')
print([str(t) for t in DEFAULT_TARGETS]) # now a node ['foo']
Default('bar')
print([str(t) for t in DEFAULT_TARGETS]) # now a node ['foo', 'bar']
Default(None)
print([str(t) for t in DEFAULT_TARGETS]) # back to []

Consequently, be sure to use DEFAULT_TARGETS only after you've made
all of your Default() calls, or else simply be careful of the order
of these statements in your SConscript files so that you don't look
for a specific default target before it's actually been added to
the list.

These variables may be accessed from custom Python modules that you
import into an SConscript file by adding the following to the Python
module:

from SCons.Script import *

Construction Variables
A construction environment has an associated dictionary of construction
variables that are used by built-in or user-supplied build rules.
Construction variable naming must follow the same rules as Python
identifier naming: the initial character must be an underscore or
letter, followed by any number of underscores, letters, or digits. A
construction environment is not a Python dictionary itself, but it can
be indexed like one to access a construction variable:

env["CC"] = "cc"
flags = env.get("CPPDEFINES", [])

Construction variables can also be retrieved and set by using the
Dictionary method of the construction environment to create an actual
dictionary:

cvars = env.Dictionary()
cvars["CC"] = "cc"

Construction variables can also be passed to the construction
environment constructor:

env = Environment(CC="cc")

or when copying a construction environment using the Clone method:

env2 = env.Clone(CC="cl.exe")

Construction variables can also be supplied as keyword arguments to a
builder, in which case those settings affect only the work done by that
builder call, and not the construction environment as a whole. This
concept is called an override:

env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])

A number of useful construction variables are automatically defined by
scons for each supported platform, and you can modify these or define
any additional construction variables for your own use, taking care not
to overwrite ones which SCons is using. The following is a list of the
possible automatically defined construction variables.

Note the actual list available at execution time will never include all
of these, as the ones detected as not being useful (wrong platform,
necessary external command or files not installed, etc.) will not be
set up. Correct build setups should be resilient to the possible
absence of certain construction variables before using them, for
example by using a Python dictionary get method to retrieve the value
and taking alternative action if the return indicates the variable is
unset. The env.Dump method can be called to examine the construction
variables set in a particular environment.

__LDMODULEVERSIONFLAGS
This construction variable automatically introduces
$_LDMODULEVERSIONFLAGS if $LDMODULEVERSION is set. Othervise it
evaluates to an empty string.

__NINJA_NO
Internal flag. Used to tell SCons whether or not to try to import
pypi's ninja python package. This is set to True when being called
by Ninja?

__SHLIBVERSIONFLAGS
This construction variable automatically introduces
$_SHLIBVERSIONFLAGS if $SHLIBVERSION is set. Othervise it evaluates
to an empty string.

APPLELINK_COMPATIBILITY_VERSION
On Mac OS X this is used to set the linker flag:
-compatibility_version

The value is specified as X[.Y[.Z]] where X is between 1 and 65535,
Y can be omitted or between 1 and 255, Z can be omitted or between
1 and 255. This value will be derived from $SHLIBVERSION if not
specified. The lowest digit will be dropped and replaced by a 0.

If the $APPLELINK_NO_COMPATIBILITY_VERSION is set then no
-compatibility_version will be output.

See MacOS's ld manpage for more details

_APPLELINK_COMPATIBILITY_VERSION
A macro (by default a generator function) used to create the linker
flags to specify apple's linker's -compatibility_version flag. The
default generator uses $APPLELINK_COMPATIBILITY_VERSION and
$APPLELINK_NO_COMPATIBILITY_VERSION and $SHLIBVERSION to determine
the correct flag.

APPLELINK_CURRENT_VERSION
On Mac OS X this is used to set the linker flag: -current_version

The value is specified as X[.Y[.Z]] where X is between 1 and 65535,
Y can be omitted or between 1 and 255, Z can be omitted or between
1 and 255. This value will be set to $SHLIBVERSION if not
specified.

If the $APPLELINK_NO_CURRENT_VERSION is set then no
-current_version will be output.

See MacOS's ld manpage for more details

_APPLELINK_CURRENT_VERSION
A macro (by default a generator function) used to create the linker
flags to specify apple's linker's -current_version flag. The
default generator uses $APPLELINK_CURRENT_VERSION and
$APPLELINK_NO_CURRENT_VERSION and $SHLIBVERSION to determine the
correct flag.

APPLELINK_NO_COMPATIBILITY_VERSION
Set this to any True (1|True|non-empty string) value to disable
adding -compatibility_version flag when generating versioned shared
libraries.

This overrides $APPLELINK_COMPATIBILITY_VERSION.

APPLELINK_NO_CURRENT_VERSION
Set this to any True (1|True|non-empty string) value to disable
adding -current_version flag when generating versioned shared
libraries.

This overrides $APPLELINK_CURRENT_VERSION.

AR
The static library archiver.

ARCHITECTURE
Specifies the system architecture for which the package is being
built. The default is the system architecture of the machine on
which SCons is running. This is used to fill in the Architecture:
field in an Ipkg control file, and the BuildArch: field in the RPM
.spec file, as well as forming part of the name of a generated RPM
package file.

See the Package builder.

ARCOM
The command line used to generate a static library from object
files.

ARCOMSTR
The string displayed when a static library is generated from object
files. If this is not set, then $ARCOM (the command line) is
displayed.

env = Environment(ARCOMSTR = "Archiving $TARGET")

ARFLAGS
General options passed to the static library archiver.

AS
The assembler.

ASCOM
The command line used to generate an object file from an
assembly-language source file.

ASCOMSTR
The string displayed when an object file is generated from an
assembly-language source file. If this is not set, then $ASCOM (the
command line) is displayed.

env = Environment(ASCOMSTR = "Assembling $TARGET")

ASFLAGS
General options passed to the assembler.

ASPPCOM
The command line used to assemble an assembly-language source file
into an object file after first running the file through the C
preprocessor. Any options specified in the $ASFLAGS and $CPPFLAGS
construction variables are included on this command line.

ASPPCOMSTR
The string displayed when an object file is generated from an
assembly-language source file after first running the file through
the C preprocessor. If this is not set, then $ASPPCOM (the command
line) is displayed.

env = Environment(ASPPCOMSTR = "Assembling $TARGET")

ASPPFLAGS
General options when an assembling an assembly-language source file
into an object file after first running the file through the C
preprocessor. The default is to use the value of $ASFLAGS.

BIBTEX
The bibliography generator for the TeX formatter and typesetter and
the LaTeX structured formatter and typesetter.

BIBTEXCOM
The command line used to call the bibliography generator for the
TeX formatter and typesetter and the LaTeX structured formatter and
typesetter.

BIBTEXCOMSTR
The string displayed when generating a bibliography for TeX or
LaTeX. If this is not set, then $BIBTEXCOM (the command line) is
displayed.

env = Environment(BIBTEXCOMSTR = "Generating bibliography $TARGET")

BIBTEXFLAGS
General options passed to the bibliography generator for the TeX
formatter and typesetter and the LaTeX structured formatter and
typesetter.

BUILDERS
A dictionary mapping the names of the builders available through
the construction environment to underlying Builder objects. Custom
builders need to be added to this to make them available.

A platform-dependent default list of builders such as Program,
Library etc. is used to populate this construction variable when
the construction environment is initialized via the
presence/absence of the tools those builders depend on. $BUILDERS
can be examined to learn which builders will actually be available
at run-time.

Note that if you initialize this construction variable through
assignment when the construction environment is created, that value
for $BUILDERS will override any defaults:

bld = Builder(action='foobuild < $SOURCE > $TARGET')
env = Environment(BUILDERS={'NewBuilder': bld})

To instead use a new Builder object in addition to the default
Builders, add your new Builder object like this:

env = Environment()
env.Append(BUILDERS={'NewBuilder': bld})

or this:

env = Environment()
env['BUILDERS']['NewBuilder'] = bld

CACHEDIR_CLASS
The class type that SCons should use when instantiating a new
CacheDir for the given environment. It must be a subclass of the
SCons.CacheDir.CacheDir class.

CC
The C compiler.

CCCOM
The command line used to compile a C source file to a (static)
object file. Any options specified in the $CFLAGS, $CCFLAGS and
$CPPFLAGS construction variables are included on this command line.
See also $SHCCCOM for compiling to shared objects.

CCCOMSTR
If set, the string displayed when a C source file is compiled to a
(static) object file. If not set, then $CCCOM (the command line) is
displayed. See also $SHCCCOMSTR for compiling to shared objects.

env = Environment(CCCOMSTR = "Compiling static object $TARGET")

CCFLAGS
General options that are passed to the C and C++ compilers. See
also $SHCCFLAGS for compiling to shared objects.

CCPCHFLAGS
Options added to the compiler command line to support building with
precompiled headers. The default value expands expands to the
appropriate Microsoft Visual C++ command-line options when the $PCH
construction variable is set.

CCPDBFLAGS
Options added to the compiler command line to support storing
debugging information in a Microsoft Visual C++ PDB file. The
default value expands expands to appropriate Microsoft Visual C++
command-line options when the $PDB construction variable is set.

The Visual C++ compiler option that SCons uses by default to
generate PDB information is /Z7. This works correctly with parallel
(-j) builds because it embeds the debug information in the
intermediate object files, as opposed to sharing a single PDB file
between multiple object files. This is also the only way to get
debug information embedded into a static library. Using the /Zi
instead may yield improved link-time performance, although parallel
builds will no longer work.

You can generate PDB files with the /Zi switch by overriding the
default $CCPDBFLAGS variable as follows:

env['CCPDBFLAGS'] = ['${(PDB and "/Zi /Fd%s" % File(PDB)) or ""}']

An alternative would be to use the /Zi to put the debugging
information in a separate .pdb file for each object file by
overriding the $CCPDBFLAGS variable as follows:

env['CCPDBFLAGS'] = '/Zi /Fd${TARGET}.pdb'

CCVERSION
The version number of the C compiler. This may or may not be set,
depending on the specific C compiler being used.

CFILESUFFIX
The suffix for C source files. This is used by the internal CFile
builder when generating C files from Lex (.l) or YACC (.y) input
files. The default suffix, of course, is .c (lower case). On
case-insensitive systems (like Windows), SCons also treats .C
(upper case) files as C files.

CFLAGS
General options that are passed to the C compiler (C only; not
C++). See also $SHCFLAGS for compiling to shared objects.

CHANGE_SPECFILE
A hook for modifying the file that controls the packaging build
(the .spec for RPM, the control for Ipkg, the .wxs for MSI). If
set, the function will be called after the SCons template for the
file has been written.

See the Package builder.

CHANGED_SOURCES
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

CHANGED_TARGETS
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

CHANGELOG
The name of a file containing the change log text to be included in
the package. This is included as the %changelog section of the RPM
.spec file.

See the Package builder.

COMPILATIONDB_COMSTR
The string displayed when the CompilationDatabase builder's action
is run.

COMPILATIONDB_PATH_FILTER
A string which instructs CompilationDatabase to only include
entries where the output member matches the pattern in the filter
string using fnmatch, which uses glob style wildcards.

The default value is an empty string '', which disables filtering.

COMPILATIONDB_USE_ABSPATH
A boolean flag to instruct CompilationDatabase whether to write the
file and output members in the compilation database using absolute
or relative paths.

The default value is False (use relative paths)

_concat
A function used to produce variables like $_CPPINCFLAGS. It takes
four mandatory arguments, and up to 4 additional optional
arguments: 1) a prefix to concatenate onto each element, 2) a list
of elements, 3) a suffix to concatenate onto each element, 4) an
environment for variable interpolation, 5) an optional function
that will be called to transform the list before concatenation, 6)
an optionally specified target (Can use TARGET), 7) an optionally
specified source (Can use SOURCE), 8) optional affect_signature
flag which will wrap non-empty returned value with $( and $) to
indicate the contents should not affect the signature of the
generated command line.

env['_CPPINCFLAGS'] = '${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE, affect_signature=False)}'

CONFIGUREDIR
The name of the directory in which Configure context test files are
written. The default is .sconf_temp in the top-level directory
containing the SConstruct file.

CONFIGURELOG
The name of the Configure context log file. The default is
config.log in the top-level directory containing the SConstruct
file.

_CPPDEFFLAGS
An automatically-generated construction variable containing the C
preprocessor command-line options to define values. The value of
$_CPPDEFFLAGS is created by respectively prepending and appending
$CPPDEFPREFIX and $CPPDEFSUFFIX to each definition in $CPPDEFINES.

CPPDEFINES
A platform independent specification of C preprocessor macro
definitions. The definitions will be added to command lines through
the automatically-generated $_CPPDEFFLAGS construction variable
(see above), which is constructed according to the type of value of
$CPPDEFINES:

If $CPPDEFINES is a string, the values of the $CPPDEFPREFIX and
$CPPDEFSUFFIX construction variables will be respectively prepended
and appended to each definition in $CPPDEFINES.

# Will add -Dxyz to POSIX compiler command lines,
# and /Dxyz to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES='xyz')

If $CPPDEFINES is a list, the values of the $CPPDEFPREFIX and
$CPPDEFSUFFIX construction variables will be respectively prepended
and appended to each element in the list. If any element is a list
or tuple, then the first item is the name being defined and the
second item is its value:

# Will add -DB=2 -DA to POSIX compiler command lines,
# and /DB=2 /DA to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES=[('B', 2), 'A'])

If $CPPDEFINES is a dictionary, the values of the $CPPDEFPREFIX and
$CPPDEFSUFFIX construction variables will be respectively prepended
and appended to each item from the dictionary. The key of each
dictionary item is a name being defined to the dictionary item's
corresponding value; if the value is None, then the name is defined
without an explicit value. Note that the resulting flags are sorted
by keyword to ensure that the order of the options on the command
line is consistent each time scons is run.

# Will add -DA -DB=2 to POSIX compiler command lines,
# and /DA /DB=2 to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES={'B':2, 'A':None})

CPPDEFPREFIX
The prefix used to specify preprocessor macro definitions on the C
compiler command line. This will be prepended to each definition in
the $CPPDEFINES construction variable when the $_CPPDEFFLAGS
variable is automatically generated.

CPPDEFSUFFIX
The suffix used to specify preprocessor macro definitions on the C
compiler command line. This will be appended to each definition in
the $CPPDEFINES construction variable when the $_CPPDEFFLAGS
variable is automatically generated.

CPPFLAGS
User-specified C preprocessor options. These will be included in
any command that uses the C preprocessor, including not just
compilation of C and C++ source files via the $CCCOM, $SHCCCOM,
$CXXCOM and $SHCXXCOM command lines, but also the $FORTRANPPCOM,
$SHFORTRANPPCOM, $F77PPCOM and $SHF77PPCOM command lines used to
compile a Fortran source file, and the $ASPPCOM command line used
to assemble an assembly language source file, after first running
each file through the C preprocessor. Note that this variable does
not contain -I (or similar) include search path options that scons
generates automatically from $CPPPATH. See $_CPPINCFLAGS, below,
for the variable that expands to those options.

_CPPINCFLAGS
An automatically-generated construction variable containing the C
preprocessor command-line options for specifying directories to be
searched for include files. The value of $_CPPINCFLAGS is created
by respectively prepending and appending $INCPREFIX and $INCSUFFIX
to each directory in $CPPPATH.

CPPPATH
The list of directories that the C preprocessor will search for
include directories. The C/C++ implicit dependency scanner will
search these directories for include files. In general it's not
advised to put include directory directives directly into $CCFLAGS
or $CXXFLAGS as the result will be non-portable and the directories
will not be searched by the dependency scanner. $CPPPATH should be
a list of path strings, or a single string, not a pathname list
joined by Python's os.sep.

Note: directory names in $CPPPATH will be looked-up relative to the
directory of the SConscript file when they are used in a command.
To force scons to look-up a directory relative to the root of the
source tree use the # prefix:

env = Environment(CPPPATH='#/include')

The directory look-up can also be forced using the Dir function:

include = Dir('include')
env = Environment(CPPPATH=include)

The directory list will be added to command lines through the
automatically-generated $_CPPINCFLAGS construction variable, which
is constructed by respectively prepending and appending the values
of the $INCPREFIX and $INCSUFFIX construction variables to each
directory in $CPPPATH. Any command lines you define that need the
$CPPPATH directory list should include $_CPPINCFLAGS:

env = Environment(CCCOM="my_compiler $_CPPINCFLAGS -c -o $TARGET $SOURCE")

CPPSUFFIXES
The list of suffixes of files that will be scanned for C
preprocessor implicit dependencies (#include lines). The default
list is:

[".c", ".C", ".cxx", ".cpp", ".c++", ".cc",
".h", ".H", ".hxx", ".hpp", ".hh",
".F", ".fpp", ".FPP",
".m", ".mm",
".S", ".spp", ".SPP"]

CXX
The C++ compiler. See also $SHCXX for compiling to shared objects..

CXXCOM
The command line used to compile a C++ source file to an object
file. Any options specified in the $CXXFLAGS and $CPPFLAGS
construction variables are included on this command line. See also
$SHCXXCOM for compiling to shared objects..

CXXCOMSTR
If set, the string displayed when a C++ source file is compiled to
a (static) object file. If not set, then $CXXCOM (the command line)
is displayed. See also $SHCXXCOMSTR for compiling to shared
objects..

env = Environment(CXXCOMSTR = "Compiling static object $TARGET")

CXXFILESUFFIX
The suffix for C++ source files. This is used by the internal
CXXFile builder when generating C++ files from Lex (.ll) or YACC
(.yy) input files. The default suffix is .cc. SCons also treats
files with the suffixes .cpp, .cxx, .c++, and .C++ as C++ files,
and files with .mm suffixes as Objective C++ files. On
case-sensitive systems (Linux, UNIX, and other POSIX-alikes), SCons
also treats .C (upper case) files as C++ files.

CXXFLAGS
General options that are passed to the C++ compiler. By default,
this includes the value of $CCFLAGS, so that setting $CCFLAGS
affects both C and C++ compilation. If you want to add C++-specific
flags, you must set or override the value of $CXXFLAGS. See also
$SHCXXFLAGS for compiling to shared objects..

CXXVERSION
The version number of the C++ compiler. This may or may not be set,
depending on the specific C++ compiler being used.

DC
The D compiler to use. See also $SHDC for compiling to shared
objects.

DCOM
The command line used to compile a D file to an object file. Any
options specified in the $DFLAGS construction variable is included
on this command line. See also $SHDCOM for compiling to shared
objects.

DCOMSTR
If set, the string displayed when a D source file is compiled to a
(static) object file. If not set, then $DCOM (the command line) is
displayed. See also $SHDCOMSTR for compiling to shared objects.

DDEBUG
List of debug tags to enable when compiling.

DDEBUGPREFIX
DDEBUGPREFIX.

DDEBUGSUFFIX
DDEBUGSUFFIX.

DESCRIPTION
A long description of the project being packaged. This is included
in the relevant section of the file that controls the packaging
build.

See the Package builder.

DESCRIPTION_lang
A language-specific long description for the specified lang. This
is used to populate a %description -l section of an RPM .spec file.

See the Package builder.

DFILESUFFIX
DFILESUFFIX.

DFLAGPREFIX
DFLAGPREFIX.

DFLAGS
General options that are passed to the D compiler.

DFLAGSUFFIX
DFLAGSUFFIX.

DINCPREFIX
DINCPREFIX.

DINCSUFFIX
DLIBFLAGSUFFIX.

Dir
A function that converts a string into a Dir instance relative to
the target being built.

Dirs
A function that converts a list of strings into a list of Dir
instances relative to the target being built.

DLIB
Name of the lib tool to use for D codes.

DLIBCOM
The command line to use when creating libraries.

DLIBDIRPREFIX
DLIBLINKPREFIX.

DLIBDIRSUFFIX
DLIBLINKSUFFIX.

DLIBFLAGPREFIX
DLIBFLAGPREFIX.

DLIBFLAGSUFFIX
DLIBFLAGSUFFIX.

DLIBLINKPREFIX
DLIBLINKPREFIX.

DLIBLINKSUFFIX
DLIBLINKSUFFIX.

DLINK
Name of the linker to use for linking systems including D sources.
See also $SHDLINK for linking shared objects.

DLINKCOM
The command line to use when linking systems including D sources.
See also $SHDLINKCOM for linking shared objects.

DLINKFLAGPREFIX
DLINKFLAGPREFIX.

DLINKFLAGS
List of linker flags. See also $SHDLINKFLAGS for linking shared
objects.

DLINKFLAGSUFFIX
DLINKFLAGSUFFIX.

DOCBOOK_DEFAULT_XSL_EPUB
The default XSLT file for the DocbookEpub builder within the
current environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_HTML
The default XSLT file for the DocbookHtml builder within the
current environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_HTMLCHUNKED
The default XSLT file for the DocbookHtmlChunked builder within the
current environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_HTMLHELP
The default XSLT file for the DocbookHtmlhelp builder within the
current environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_MAN
The default XSLT file for the DocbookMan builder within the current
environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_PDF
The default XSLT file for the DocbookPdf builder within the current
environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_SLIDESHTML
The default XSLT file for the DocbookSlidesHtml builder within the
current environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_SLIDESPDF
The default XSLT file for the DocbookSlidesPdf builder within the
current environment, if no other XSLT gets specified via keyword.

DOCBOOK_FOP
The path to the PDF renderer fop or xep, if one of them is
installed (fop gets checked first).

DOCBOOK_FOPCOM
The full command-line for the PDF renderer fop or xep.

DOCBOOK_FOPCOMSTR
The string displayed when a renderer like fop or xep is used to
create PDF output from an XML file.

DOCBOOK_FOPFLAGS
Additonal command-line flags for the PDF renderer fop or xep.

DOCBOOK_XMLLINT
The path to the external executable xmllint, if it's installed.
Note, that this is only used as last fallback for resolving
XIncludes, if no lxml Python binding can be imported in the current
system.

DOCBOOK_XMLLINTCOM
The full command-line for the external executable xmllint.

DOCBOOK_XMLLINTCOMSTR
The string displayed when xmllint is used to resolve XIncludes for
a given XML file.

DOCBOOK_XMLLINTFLAGS
Additonal command-line flags for the external executable xmllint.

DOCBOOK_XSLTPROC
The path to the external executable xsltproc (or saxon, xalan), if
one of them is installed. Note, that this is only used as last
fallback for XSL transformations, if no lxml Python binding can be
imported in the current system.

DOCBOOK_XSLTPROCCOM
The full command-line for the external executable xsltproc (or
saxon, xalan).

DOCBOOK_XSLTPROCCOMSTR
The string displayed when xsltproc is used to transform an XML file
via a given XSLT stylesheet.

DOCBOOK_XSLTPROCFLAGS
Additonal command-line flags for the external executable xsltproc
(or saxon, xalan).

DOCBOOK_XSLTPROCPARAMS
Additonal parameters that are not intended for the XSLT processor
executable, but the XSL processing itself. By default, they get
appended at the end of the command line for saxon and saxon-xslt,
respectively.

DPATH
List of paths to search for import modules.

DRPATHPREFIX
DRPATHPREFIX.

DRPATHSUFFIX
DRPATHSUFFIX.

DSUFFIXES
The list of suffixes of files that will be scanned for imported D
package files. The default list is ['.d'].

DVERPREFIX
DVERPREFIX.

DVERSIONS
List of version tags to enable when compiling.

DVERSUFFIX
DVERSUFFIX.

DVIPDF
The TeX DVI file to PDF file converter.

DVIPDFCOM
The command line used to convert TeX DVI files into a PDF file.

DVIPDFCOMSTR
The string displayed when a TeX DVI file is converted into a PDF
file. If this is not set, then $DVIPDFCOM (the command line) is
displayed.

DVIPDFFLAGS
General options passed to the TeX DVI file to PDF file converter.

DVIPS
The TeX DVI file to PostScript converter.

DVIPSFLAGS
General options passed to the TeX DVI file to PostScript converter.

ENV
A dictionary of environment variables to use when invoking
commands. When $ENV is used in a command all list values will be
joined using the path separator and any other non-string values
will simply be coerced to a string. Note that, by default, scons
does not propagate the environment in effect when you execute scons
to the commands used to build target files. This is so that builds
will be guaranteed repeatable regardless of the environment
variables set at the time scons is invoked.

If you want to propagate your environment variables to the commands
executed to build target files, you must do so explicitly:

import os
env = Environment(ENV=os.environ.copy())

Note that you can choose only to propagate certain environment
variables. A common example is the system PATH environment
variable, so that scons uses the same utilities as the invoking
shell (or other process):

import os
env = Environment(ENV={'PATH': os.environ['PATH']})

ESCAPE
A function that will be called to escape shell special characters
in command lines. The function should take one argument: the
command line string to escape; and should return the escaped
command line.

F03
The Fortran 03 compiler. You should normally set the $FORTRAN
variable, which specifies the default Fortran compiler for all
Fortran versions. You only need to set $F03 if you need to use a
specific compiler or compiler version for Fortran 03 files.

F03COM
The command line used to compile a Fortran 03 source file to an
object file. You only need to set $F03COM if you need to use a
specific command line for Fortran 03 files. You should normally set
the $FORTRANCOM variable, which specifies the default command line
for all Fortran versions.

F03COMSTR
If set, the string displayed when a Fortran 03 source file is
compiled to an object file. If not set, then $F03COM or $FORTRANCOM
(the command line) is displayed.

F03FILESUFFIXES
The list of file extensions for which the F03 dialect will be used.
By default, this is ['.f03']

F03FLAGS
General user-specified options that are passed to the Fortran 03
compiler. Note that this variable does not contain -I (or similar)
include search path options that scons generates automatically from
$F03PATH. See $_F03INCFLAGS below, for the variable that expands to
those options. You only need to set $F03FLAGS if you need to define
specific user options for Fortran 03 files. You should normally set
the $FORTRANFLAGS variable, which specifies the user-specified
options passed to the default Fortran compiler for all Fortran
versions.

_F03INCFLAGS
An automatically-generated construction variable containing the
Fortran 03 compiler command-line options for specifying directories
to be searched for include files. The value of $_F03INCFLAGS is
created by appending $INCPREFIX and $INCSUFFIX to the beginning and
end of each directory in $F03PATH.

F03PATH
The list of directories that the Fortran 03 compiler will search
for include directories. The implicit dependency scanner will
search these directories for include files. Don't explicitly put
include directory arguments in $F03FLAGS because the result will be
non-portable and the directories will not be searched by the
dependency scanner. Note: directory names in $F03PATH will be
looked-up relative to the SConscript directory when they are used
in a command. To force scons to look-up a directory relative to the
root of the source tree use #: You only need to set $F03PATH if you
need to define a specific include path for Fortran 03 files. You
should normally set the $FORTRANPATH variable, which specifies the
include path for the default Fortran compiler for all Fortran
versions.

env = Environment(F03PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F03PATH=include)

The directory list will be added to command lines through the
automatically-generated $_F03INCFLAGS construction variable, which
is constructed by appending the values of the $INCPREFIX and
$INCSUFFIX construction variables to the beginning and end of each
directory in $F03PATH. Any command lines you define that need the
F03PATH directory list should include $_F03INCFLAGS:

env = Environment(F03COM="my_compiler $_F03INCFLAGS -c -o $TARGET $SOURCE")

F03PPCOM
The command line used to compile a Fortran 03 source file to an
object file after first running the file through the C
preprocessor. Any options specified in the $F03FLAGS and $CPPFLAGS
construction variables are included on this command line. You only
need to set $F03PPCOM if you need to use a specific C-preprocessor
command line for Fortran 03 files. You should normally set the
$FORTRANPPCOM variable, which specifies the default C-preprocessor
command line for all Fortran versions.

F03PPCOMSTR
If set, the string displayed when a Fortran 03 source file is
compiled to an object file after first running the file through the
C preprocessor. If not set, then $F03PPCOM or $FORTRANPPCOM (the
command line) is displayed.

F03PPFILESUFFIXES
The list of file extensions for which the compilation +
preprocessor pass for F03 dialect will be used. By default, this is
empty.

F08
The Fortran 08 compiler. You should normally set the $FORTRAN
variable, which specifies the default Fortran compiler for all
Fortran versions. You only need to set $F08 if you need to use a
specific compiler or compiler version for Fortran 08 files.

F08COM
The command line used to compile a Fortran 08 source file to an
object file. You only need to set $F08COM if you need to use a
specific command line for Fortran 08 files. You should normally set
the $FORTRANCOM variable, which specifies the default command line
for all Fortran versions.

F08COMSTR
If set, the string displayed when a Fortran 08 source file is
compiled to an object file. If not set, then $F08COM or $FORTRANCOM
(the command line) is displayed.

F08FILESUFFIXES
The list of file extensions for which the F08 dialect will be used.
By default, this is ['.f08']

F08FLAGS
General user-specified options that are passed to the Fortran 08
compiler. Note that this variable does not contain -I (or similar)
include search path options that scons generates automatically from
$F08PATH. See $_F08INCFLAGS below, for the variable that expands to
those options. You only need to set $F08FLAGS if you need to define
specific user options for Fortran 08 files. You should normally set
the $FORTRANFLAGS variable, which specifies the user-specified
options passed to the default Fortran compiler for all Fortran
versions.

_F08INCFLAGS
An automatically-generated construction variable containing the
Fortran 08 compiler command-line options for specifying directories
to be searched for include files. The value of $_F08INCFLAGS is
created by appending $INCPREFIX and $INCSUFFIX to the beginning and
end of each directory in $F08PATH.

F08PATH
The list of directories that the Fortran 08 compiler will search
for include directories. The implicit dependency scanner will
search these directories for include files. Don't explicitly put
include directory arguments in $F08FLAGS because the result will be
non-portable and the directories will not be searched by the
dependency scanner. Note: directory names in $F08PATH will be
looked-up relative to the SConscript directory when they are used
in a command. To force scons to look-up a directory relative to the
root of the source tree use #: You only need to set $F08PATH if you
need to define a specific include path for Fortran 08 files. You
should normally set the $FORTRANPATH variable, which specifies the
include path for the default Fortran compiler for all Fortran
versions.

env = Environment(F08PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F08PATH=include)

The directory list will be added to command lines through the
automatically-generated $_F08INCFLAGS construction variable, which
is constructed by appending the values of the $INCPREFIX and
$INCSUFFIX construction variables to the beginning and end of each
directory in $F08PATH. Any command lines you define that need the
F08PATH directory list should include $_F08INCFLAGS:

env = Environment(F08COM="my_compiler $_F08INCFLAGS -c -o $TARGET $SOURCE")

F08PPCOM
The command line used to compile a Fortran 08 source file to an
object file after first running the file through the C
preprocessor. Any options specified in the $F08FLAGS and $CPPFLAGS
construction variables are included on this command line. You only
need to set $F08PPCOM if you need to use a specific C-preprocessor
command line for Fortran 08 files. You should normally set the
$FORTRANPPCOM variable, which specifies the default C-preprocessor
command line for all Fortran versions.

F08PPCOMSTR
If set, the string displayed when a Fortran 08 source file is
compiled to an object file after first running the file through the
C preprocessor. If not set, then $F08PPCOM or $FORTRANPPCOM (the
command line) is displayed.

F08PPFILESUFFIXES
The list of file extensions for which the compilation +
preprocessor pass for F08 dialect will be used. By default, this is
empty.

F77
The Fortran 77 compiler. You should normally set the $FORTRAN
variable, which specifies the default Fortran compiler for all
Fortran versions. You only need to set $F77 if you need to use a
specific compiler or compiler version for Fortran 77 files.

F77COM
The command line used to compile a Fortran 77 source file to an
object file. You only need to set $F77COM if you need to use a
specific command line for Fortran 77 files. You should normally set
the $FORTRANCOM variable, which specifies the default command line
for all Fortran versions.

F77COMSTR
If set, the string displayed when a Fortran 77 source file is
compiled to an object file. If not set, then $F77COM or $FORTRANCOM
(the command line) is displayed.

F77FILESUFFIXES
The list of file extensions for which the F77 dialect will be used.
By default, this is ['.f77']

F77FLAGS
General user-specified options that are passed to the Fortran 77
compiler. Note that this variable does not contain -I (or similar)
include search path options that scons generates automatically from
$F77PATH. See $_F77INCFLAGS below, for the variable that expands to
those options. You only need to set $F77FLAGS if you need to define
specific user options for Fortran 77 files. You should normally set
the $FORTRANFLAGS variable, which specifies the user-specified
options passed to the default Fortran compiler for all Fortran
versions.

_F77INCFLAGS
An automatically-generated construction variable containing the
Fortran 77 compiler command-line options for specifying directories
to be searched for include files. The value of $_F77INCFLAGS is
created by appending $INCPREFIX and $INCSUFFIX to the beginning and
end of each directory in $F77PATH.

F77PATH
The list of directories that the Fortran 77 compiler will search
for include directories. The implicit dependency scanner will
search these directories for include files. Don't explicitly put
include directory arguments in $F77FLAGS because the result will be
non-portable and the directories will not be searched by the
dependency scanner. Note: directory names in $F77PATH will be
looked-up relative to the SConscript directory when they are used
in a command. To force scons to look-up a directory relative to the
root of the source tree use #: You only need to set $F77PATH if you
need to define a specific include path for Fortran 77 files. You
should normally set the $FORTRANPATH variable, which specifies the
include path for the default Fortran compiler for all Fortran
versions.

env = Environment(F77PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F77PATH=include)

The directory list will be added to command lines through the
automatically-generated $_F77INCFLAGS construction variable, which
is constructed by appending the values of the $INCPREFIX and
$INCSUFFIX construction variables to the beginning and end of each
directory in $F77PATH. Any command lines you define that need the
F77PATH directory list should include $_F77INCFLAGS:

env = Environment(F77COM="my_compiler $_F77INCFLAGS -c -o $TARGET $SOURCE")

F77PPCOM
The command line used to compile a Fortran 77 source file to an
object file after first running the file through the C
preprocessor. Any options specified in the $F77FLAGS and $CPPFLAGS
construction variables are included on this command line. You only
need to set $F77PPCOM if you need to use a specific C-preprocessor
command line for Fortran 77 files. You should normally set the
$FORTRANPPCOM variable, which specifies the default C-preprocessor
command line for all Fortran versions.

F77PPCOMSTR
If set, the string displayed when a Fortran 77 source file is
compiled to an object file after first running the file through the
C preprocessor. If not set, then $F77PPCOM or $FORTRANPPCOM (the
command line) is displayed.

F77PPFILESUFFIXES
The list of file extensions for which the compilation +
preprocessor pass for F77 dialect will be used. By default, this is
empty.

F90
The Fortran 90 compiler. You should normally set the $FORTRAN
variable, which specifies the default Fortran compiler for all
Fortran versions. You only need to set $F90 if you need to use a
specific compiler or compiler version for Fortran 90 files.

F90COM
The command line used to compile a Fortran 90 source file to an
object file. You only need to set $F90COM if you need to use a
specific command line for Fortran 90 files. You should normally set
the $FORTRANCOM variable, which specifies the default command line
for all Fortran versions.

F90COMSTR
If set, the string displayed when a Fortran 90 source file is
compiled to an object file. If not set, then $F90COM or $FORTRANCOM
(the command line) is displayed.

F90FILESUFFIXES
The list of file extensions for which the F90 dialect will be used.
By default, this is ['.f90']

F90FLAGS
General user-specified options that are passed to the Fortran 90
compiler. Note that this variable does not contain -I (or similar)
include search path options that scons generates automatically from
$F90PATH. See $_F90INCFLAGS below, for the variable that expands to
those options. You only need to set $F90FLAGS if you need to define
specific user options for Fortran 90 files. You should normally set
the $FORTRANFLAGS variable, which specifies the user-specified
options passed to the default Fortran compiler for all Fortran
versions.

_F90INCFLAGS
An automatically-generated construction variable containing the
Fortran 90 compiler command-line options for specifying directories
to be searched for include files. The value of $_F90INCFLAGS is
created by appending $INCPREFIX and $INCSUFFIX to the beginning and
end of each directory in $F90PATH.

F90PATH
The list of directories that the Fortran 90 compiler will search
for include directories. The implicit dependency scanner will
search these directories for include files. Don't explicitly put
include directory arguments in $F90FLAGS because the result will be
non-portable and the directories will not be searched by the
dependency scanner. Note: directory names in $F90PATH will be
looked-up relative to the SConscript directory when they are used
in a command. To force scons to look-up a directory relative to the
root of the source tree use #: You only need to set $F90PATH if you
need to define a specific include path for Fortran 90 files. You
should normally set the $FORTRANPATH variable, which specifies the
include path for the default Fortran compiler for all Fortran
versions.

env = Environment(F90PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F90PATH=include)

The directory list will be added to command lines through the
automatically-generated $_F90INCFLAGS construction variable, which
is constructed by appending the values of the $INCPREFIX and
$INCSUFFIX construction variables to the beginning and end of each
directory in $F90PATH. Any command lines you define that need the
F90PATH directory list should include $_F90INCFLAGS:

env = Environment(F90COM="my_compiler $_F90INCFLAGS -c -o $TARGET $SOURCE")

F90PPCOM
The command line used to compile a Fortran 90 source file to an
object file after first running the file through the C
preprocessor. Any options specified in the $F90FLAGS and $CPPFLAGS
construction variables are included on this command line. You only
need to set $F90PPCOM if you need to use a specific C-preprocessor
command line for Fortran 90 files. You should normally set the
$FORTRANPPCOM variable, which specifies the default C-preprocessor
command line for all Fortran versions.

F90PPCOMSTR
If set, the string displayed when a Fortran 90 source file is
compiled after first running the file through the C preprocessor.
If not set, then $F90PPCOM or $FORTRANPPCOM (the command line) is
displayed.

F90PPFILESUFFIXES
The list of file extensions for which the compilation +
preprocessor pass for F90 dialect will be used. By default, this is
empty.

F95
The Fortran 95 compiler. You should normally set the $FORTRAN
variable, which specifies the default Fortran compiler for all
Fortran versions. You only need to set $F95 if you need to use a
specific compiler or compiler version for Fortran 95 files.

F95COM
The command line used to compile a Fortran 95 source file to an
object file. You only need to set $F95COM if you need to use a
specific command line for Fortran 95 files. You should normally set
the $FORTRANCOM variable, which specifies the default command line
for all Fortran versions.

F95COMSTR
If set, the string displayed when a Fortran 95 source file is
compiled to an object file. If not set, then $F95COM or $FORTRANCOM
(the command line) is displayed.

F95FILESUFFIXES
The list of file extensions for which the F95 dialect will be used.
By default, this is ['.f95']

F95FLAGS
General user-specified options that are passed to the Fortran 95
compiler. Note that this variable does not contain -I (or similar)
include search path options that scons generates automatically from
$F95PATH. See $_F95INCFLAGS below, for the variable that expands to
those options. You only need to set $F95FLAGS if you need to define
specific user options for Fortran 95 files. You should normally set
the $FORTRANFLAGS variable, which specifies the user-specified
options passed to the default Fortran compiler for all Fortran
versions.

_F95INCFLAGS
An automatically-generated construction variable containing the
Fortran 95 compiler command-line options for specifying directories
to be searched for include files. The value of $_F95INCFLAGS is
created by appending $INCPREFIX and $INCSUFFIX to the beginning and
end of each directory in $F95PATH.

F95PATH
The list of directories that the Fortran 95 compiler will search
for include directories. The implicit dependency scanner will
search these directories for include files. Don't explicitly put
include directory arguments in $F95FLAGS because the result will be
non-portable and the directories will not be searched by the
dependency scanner. Note: directory names in $F95PATH will be
looked-up relative to the SConscript directory when they are used
in a command. To force scons to look-up a directory relative to the
root of the source tree use #: You only need to set $F95PATH if you
need to define a specific include path for Fortran 95 files. You
should normally set the $FORTRANPATH variable, which specifies the
include path for the default Fortran compiler for all Fortran
versions.

env = Environment(F95PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F95PATH=include)

The directory list will be added to command lines through the
automatically-generated $_F95INCFLAGS construction variable, which
is constructed by appending the values of the $INCPREFIX and
$INCSUFFIX construction variables to the beginning and end of each
directory in $F95PATH. Any command lines you define that need the
F95PATH directory list should include $_F95INCFLAGS:

env = Environment(F95COM="my_compiler $_F95INCFLAGS -c -o $TARGET $SOURCE")

F95PPCOM
The command line used to compile a Fortran 95 source file to an
object file after first running the file through the C
preprocessor. Any options specified in the $F95FLAGS and $CPPFLAGS
construction variables are included on this command line. You only
need to set $F95PPCOM if you need to use a specific C-preprocessor
command line for Fortran 95 files. You should normally set the
$FORTRANPPCOM variable, which specifies the default C-preprocessor
command line for all Fortran versions.

F95PPCOMSTR
If set, the string displayed when a Fortran 95 source file is
compiled to an object file after first running the file through the
C preprocessor. If not set, then $F95PPCOM or $FORTRANPPCOM (the
command line) is displayed.

F95PPFILESUFFIXES
The list of file extensions for which the compilation +
preprocessor pass for F95 dialect will be used. By default, this is
empty.

File
A function that converts a string into a File instance relative to
the target being built.

FORTRAN
The default Fortran compiler for all versions of Fortran.

FORTRANCOM
The command line used to compile a Fortran source file to an object
file. By default, any options specified in the $FORTRANFLAGS,
$CPPFLAGS, $_CPPDEFFLAGS, $_FORTRANMODFLAG, and $_FORTRANINCFLAGS
construction variables are included on this command line.

FORTRANCOMSTR
If set, the string displayed when a Fortran source file is compiled
to an object file. If not set, then $FORTRANCOM (the command line)
is displayed.

FORTRANFILESUFFIXES
The list of file extensions for which the FORTRAN dialect will be
used. By default, this is ['.f', '.for', '.ftn']

FORTRANFLAGS
General user-specified options that are passed to the Fortran
compiler. Note that this variable does not contain -I (or similar)
include or module search path options that scons generates
automatically from $FORTRANPATH. See $_FORTRANINCFLAGS and
$_FORTRANMODFLAG, below, for the variables that expand those
options.

_FORTRANINCFLAGS
An automatically-generated construction variable containing the
Fortran compiler command-line options for specifying directories to
be searched for include files and module files. The value of
$_FORTRANINCFLAGS is created by respectively prepending and
appending $INCPREFIX and $INCSUFFIX to the beginning and end of
each directory in $FORTRANPATH.

FORTRANMODDIR
Directory location where the Fortran compiler should place any
module files it generates. This variable is empty, by default. Some
Fortran compilers will internally append this directory in the
search path for module files, as well.

FORTRANMODDIRPREFIX
The prefix used to specify a module directory on the Fortran
compiler command line. This will be prepended to the beginning of
the directory in the $FORTRANMODDIR construction variables when the
$_FORTRANMODFLAG variables is automatically generated.

FORTRANMODDIRSUFFIX
The suffix used to specify a module directory on the Fortran
compiler command line. This will be appended to the end of the
directory in the $FORTRANMODDIR construction variables when the
$_FORTRANMODFLAG variables is automatically generated.

_FORTRANMODFLAG
An automatically-generated construction variable containing the
Fortran compiler command-line option for specifying the directory
location where the Fortran compiler should place any module files
that happen to get generated during compilation. The value of
$_FORTRANMODFLAG is created by respectively prepending and
appending $FORTRANMODDIRPREFIX and $FORTRANMODDIRSUFFIX to the
beginning and end of the directory in $FORTRANMODDIR.

FORTRANMODPREFIX
The module file prefix used by the Fortran compiler. SCons assumes
that the Fortran compiler follows the quasi-standard naming
convention for module files of module_name.mod. As a result, this
variable is left empty, by default. For situations in which the
compiler does not necessarily follow the normal convention, the
user may use this variable. Its value will be appended to every
module file name as scons attempts to resolve dependencies.

FORTRANMODSUFFIX
The module file suffix used by the Fortran compiler. SCons assumes
that the Fortran compiler follows the quasi-standard naming
convention for module files of module_name.mod. As a result, this
variable is set to ".mod", by default. For situations in which the
compiler does not necessarily follow the normal convention, the
user may use this variable. Its value will be appended to every
module file name as scons attempts to resolve dependencies.

FORTRANPATH
The list of directories that the Fortran compiler will search for
include files and (for some compilers) module files. The Fortran
implicit dependency scanner will search these directories for
include files (but not module files since they are autogenerated
and, as such, may not actually exist at the time the scan takes
place). Don't explicitly put include directory arguments in
FORTRANFLAGS because the result will be non-portable and the
directories will not be searched by the dependency scanner. Note:
directory names in FORTRANPATH will be looked-up relative to the
SConscript directory when they are used in a command. To force
scons to look-up a directory relative to the root of the source
tree use #:

env = Environment(FORTRANPATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(FORTRANPATH=include)

The directory list will be added to command lines through the
automatically-generated $_FORTRANINCFLAGS construction variable,
which is constructed by respectively prepending and appending the
values of the $INCPREFIX and $INCSUFFIX construction variables to
the beginning and end of each directory in $FORTRANPATH. Any
command lines you define that need the FORTRANPATH directory list
should include $_FORTRANINCFLAGS:

env = Environment(FORTRANCOM="my_compiler $_FORTRANINCFLAGS -c -o $TARGET $SOURCE")

FORTRANPPCOM
The command line used to compile a Fortran source file to an object
file after first running the file through the C preprocessor. By
default, any options specified in the $FORTRANFLAGS, $CPPFLAGS,
$_CPPDEFFLAGS, $_FORTRANMODFLAG, and $_FORTRANINCFLAGS construction
variables are included on this command line.

FORTRANPPCOMSTR
If set, the string displayed when a Fortran source file is compiled
to an object file after first running the file through the C
preprocessor. If not set, then $FORTRANPPCOM (the command line) is
displayed.

FORTRANPPFILESUFFIXES
The list of file extensions for which the compilation +
preprocessor pass for FORTRAN dialect will be used. By default,
this is ['.fpp', '.FPP']

FORTRANSUFFIXES
The list of suffixes of files that will be scanned for Fortran
implicit dependencies (INCLUDE lines and USE statements). The
default list is:

[".f", ".F", ".for", ".FOR", ".ftn", ".FTN", ".fpp", ".FPP",
".f77", ".F77", ".f90", ".F90", ".f95", ".F95"]

FRAMEWORKPATH
On Mac OS X with gcc, a list containing the paths to search for
frameworks. Used by the compiler to find framework-style includes
like #include <Fmwk/Header.h>. Used by the linker to find
user-specified frameworks when linking (see $FRAMEWORKS). For
example:

env.AppendUnique(FRAMEWORKPATH='#myframeworkdir')

will add

... -Fmyframeworkdir

to the compiler and linker command lines.

_FRAMEWORKPATH
On Mac OS X with gcc, an automatically-generated construction
variable containing the linker command-line options corresponding
to $FRAMEWORKPATH.

FRAMEWORKPATHPREFIX
On Mac OS X with gcc, the prefix to be used for the FRAMEWORKPATH
entries. (see $FRAMEWORKPATH). The default value is -F.

FRAMEWORKPREFIX
On Mac OS X with gcc, the prefix to be used for linking in
frameworks (see $FRAMEWORKS). The default value is -framework.

FRAMEWORKS
On Mac OS X with gcc, a list of the framework names to be linked
into a program or shared library or bundle. The default value is
the empty list. For example:

env.AppendUnique(FRAMEWORKS=Split('System Cocoa SystemConfiguration'))

_FRAMEWORKS
On Mac OS X with gcc, an automatically-generated construction
variable containing the linker command-line options for linking
with FRAMEWORKS.

FRAMEWORKSFLAGS
On Mac OS X with gcc, general user-supplied frameworks options to
be added at the end of a command line building a loadable module.
(This has been largely superseded by the $FRAMEWORKPATH,
$FRAMEWORKPATHPREFIX, $FRAMEWORKPREFIX and $FRAMEWORKS variables
described above.)

GS
The Ghostscript program used to, for example, convert PostScript to
PDF files.

GSCOM
The full Ghostscript command line used for the conversion process.
Its default value is "$GS $GSFLAGS -sOutputFile=$TARGET $SOURCES".

GSCOMSTR
The string displayed when Ghostscript is called for the conversion
process. If this is not set (the default), then $GSCOM (the command
line) is displayed.

GSFLAGS
General options passed to the Ghostscript program, when converting
PostScript to PDF files for example. Its default value is
"-dNOPAUSE -dBATCH -sDEVICE=pdfwrite"

HOST_ARCH
The name of the host hardware architecture used to create the
Environment. If a platform is specified when creating the
Environment, then that Platform's logic will handle setting this
value. This value is immutable, and should not be changed by the
user after the Environment is initialized. Currently only set for
Win32.

Sets the host architecture for the Visual C++ compiler. If not set,
default to the detected host architecture: note that this may
depend on the python you are using. This variable must be passed as
an argument to the Environment() constructor; setting it later has
no effect.

Valid values are the same as for $TARGET_ARCH.

This is currently only used on Windows, but in the future it may be
used on other OSes as well.

HOST_OS
The name of the host operating system used to create the
Environment. If a platform is specified when creating the
Environment, then that Platform's logic will handle setting this
value. This value is immutable, and should not be changed by the
user after the Environment is initialized. Currently only set for
Win32.

IDLSUFFIXES
The list of suffixes of files that will be scanned for IDL implicit
dependencies (#include or import lines). The default list is:

[".idl", ".IDL"]

IMPLIBNOVERSIONSYMLINKS
Used to override $SHLIBNOVERSIONSYMLINKS/$LDMODULENOVERSIONSYMLINKS
when creating versioned import library for a shared
library/loadable module. If not defined, then
$SHLIBNOVERSIONSYMLINKS/$LDMODULENOVERSIONSYMLINKS is used to
determine whether to disable symlink generation or not.

IMPLIBPREFIX
The prefix used for import library names. For example, cygwin uses
import libraries (libfoo.dll.a) in pair with dynamic libraries
(cygfoo.dll). The cyglink linker sets $IMPLIBPREFIX to 'lib' and
$SHLIBPREFIX to 'cyg'.

IMPLIBSUFFIX
The suffix used for import library names. For example, cygwin uses
import libraries (libfoo.dll.a) in pair with dynamic libraries
(cygfoo.dll). The cyglink linker sets $IMPLIBSUFFIX to '.dll.a' and
$SHLIBSUFFIX to '.dll'.

IMPLIBVERSION
Used to override $SHLIBVERSION/$LDMODULEVERSION when generating
versioned import library for a shared library/loadable module. If
undefined, the $SHLIBVERSION/$LDMODULEVERSION is used to determine
the version of versioned import library.

IMPLICIT_COMMAND_DEPENDENCIES
Controls whether or not SCons will add implicit dependencies for
the commands executed to build targets.

By default, SCons will add to each target an implicit dependency on
the command represented by the first argument of any command line
it executes (which is typically the command itself). By setting
such a dependency, SCons can determine that a target should be
rebuilt if the command changes, such as when a compiler is upgraded
to a new version. The specific file for the dependency is found by
searching the PATH variable in the ENV dictionary in the
construction environment used to execute the command. The default
is the same as setting the construction variable
$IMPLICIT_COMMAND_DEPENDENCIES to a True-like value ("true", "yes",
or "1" - but not a number greater than one, as that has a different
meaning).

Action strings can be segmented by the use of an AND operator, &&.
In a segemented string, each segment is a separate "command line",
these are run sequentially until one fails or the entire sequence
has been executed. If an action string is segmented, then the
selected behavior of $IMPLICIT_COMMAND_DEPENDENCIES is applied to
each segment.

If $IMPLICIT_COMMAND_DEPENDENCIES is set to a False-like value
("none", "false", "no", "0", etc.), then the implicit dependency
will not be added to the targets built with that construction
environment.

If $IMPLICIT_COMMAND_DEPENDENCIES is set to "2" or higher, then
that number of arguments in the command line will be scanned for
relative or absolute paths. If any are present, they will be added
as implicit dependencies to the targets built with that
construction environment. The first argument in the command line
will be searched for using the PATH variable in the ENV dictionary
in the construction environment used to execute the command. The
other arguments will only be found if they are absolute paths or
valid paths relative to the working directory.

If $IMPLICIT_COMMAND_DEPENDENCIES is set to "all", then all
arguments in the command line will be scanned for relative or
absolute paths. If any are present, they will be added as implicit
dependencies to the targets built with that construction
environment. The first argument in the command line will be
searched for using the PATH variable in the ENV dictionary in the
construction environment used to execute the command. The other
arguments will only be found if they are absolute paths or valid
paths relative to the working directory.

env = Environment(IMPLICIT_COMMAND_DEPENDENCIES=False)

INCPREFIX
The prefix used to specify an include directory on the C compiler
command line. This will be prepended to each directory in the
$CPPPATH and $FORTRANPATH construction variables when the
$_CPPINCFLAGS and $_FORTRANINCFLAGS variables are automatically
generated.

INCSUFFIX
The suffix used to specify an include directory on the C compiler
command line. This will be appended to each directory in the
$CPPPATH and $FORTRANPATH construction variables when the
$_CPPINCFLAGS and $_FORTRANINCFLAGS variables are automatically
generated.

INSTALL
A function to be called to install a file into a destination file
name. The default function copies the file into the destination
(and sets the destination file's mode and permission bits to match
the source file's). The function takes the following arguments:

def install(dest, source, env):

dest is the path name of the destination file. source is the path
name of the source file. env is the construction environment (a
dictionary of construction values) in force for this file
installation.

INSTALLSTR
The string displayed when a file is installed into a destination
file name. The default is:

Install file: "$SOURCE" as "$TARGET"

INTEL_C_COMPILER_VERSION
Set by the intelc Tool to the major version number of the Intel C
compiler selected for use.

JAR
The Java archive tool.

JARCHDIR
The directory to which the Java archive tool should change (using
the -C option).

JARCOM
The command line used to call the Java archive tool.

JARCOMSTR
The string displayed when the Java archive tool is called If this
is not set, then $JARCOM (the command line) is displayed.

env = Environment(JARCOMSTR="JARchiving $SOURCES into $TARGET")

JARFLAGS
General options passed to the Java archive tool. By default this is
set to cf to create the necessary jar file.

JARSUFFIX
The suffix for Java archives: .jar by default.

JAVABOOTCLASSPATH
Specifies the list of directories that will be added to the javac
command line via the -bootclasspath option. The individual
directory names will be separated by the operating system's path
separate character (: on UNIX/Linux/POSIX, ; on Windows).

JAVAC
The Java compiler.

JAVACCOM
The command line used to compile a directory tree containing Java
source files to corresponding Java class files. Any options
specified in the $JAVACFLAGS construction variable are included on
this command line.

JAVACCOMSTR
The string displayed when compiling a directory tree of Java source
files to corresponding Java class files. If this is not set, then
$JAVACCOM (the command line) is displayed.

env = Environment(JAVACCOMSTR="Compiling class files $TARGETS from $SOURCES")

JAVACFLAGS
General options that are passed to the Java compiler.

JAVACLASSDIR
The directory in which Java class files may be found. This is
stripped from the beginning of any Java .class file names supplied
to the JavaH builder.

JAVACLASSPATH
Specifies the list of directories that will be searched for Java
.class file. The directories in this list will be added to the
javac and javah command lines via the -classpath option. The
individual directory names will be separated by the operating
system's path separate character (: on UNIX/Linux/POSIX, ; on
Windows).

Note that this currently just adds the specified directory via the
-classpath option. SCons does not currently search the
$JAVACLASSPATH directories for dependency .class files.

JAVACLASSSUFFIX
The suffix for Java class files; .class by default.

JAVAH
The Java generator for C header and stub files.

JAVAHCOM
The command line used to generate C header and stub files from Java
classes. Any options specified in the $JAVAHFLAGS construction
variable are included on this command line.

JAVAHCOMSTR
The string displayed when C header and stub files are generated
from Java classes. If this is not set, then $JAVAHCOM (the command
line) is displayed.

env = Environment(JAVAHCOMSTR="Generating header/stub file(s) $TARGETS from $SOURCES")

JAVAHFLAGS
General options passed to the C header and stub file generator for
Java classes.

JAVAINCLUDES
Include path for Java header files (such as jni.h)

JAVASOURCEPATH
Specifies the list of directories that will be searched for input
.java file. The directories in this list will be added to the javac
command line via the -sourcepath option. The individual directory
names will be separated by the operating system's path separate
character (: on UNIX/Linux/POSIX, ; on Windows).

Note that this currently just adds the specified directory via the
-sourcepath option. SCons does not currently search the
$JAVASOURCEPATH directories for dependency .java files.

JAVASUFFIX
The suffix for Java files; .java by default.

JAVAVERSION
Specifies the Java version being used by the Java builder. This is
not currently used to select one version of the Java compiler vs.
another. Instead, you should set this to specify the version of
Java supported by your javac compiler. The default is 1.4.

This is sometimes necessary because Java 1.5 changed the file names
that are created for nested anonymous inner classes, which can
cause a mismatch with the files that SCons expects will be
generated by the javac compiler. Setting $JAVAVERSION to 1.5 (or
1.6, as appropriate) can make SCons realize that a Java 1.5 or 1.6
build is actually up to date.

LATEX
The LaTeX structured formatter and typesetter.

LATEXCOM
The command line used to call the LaTeX structured formatter and
typesetter.

LATEXCOMSTR
The string displayed when calling the LaTeX structured formatter
and typesetter. If this is not set, then $LATEXCOM (the command
line) is displayed.

env = Environment(LATEXCOMSTR = "Building $TARGET from LaTeX input $SOURCES")

LATEXFLAGS
General options passed to the LaTeX structured formatter and
typesetter.

LATEXRETRIES
The maximum number of times that LaTeX will be re-run if the .log
generated by the $LATEXCOM command indicates that there are
undefined references. The default is to try to resolve undefined
references by re-running LaTeX up to three times.

LATEXSUFFIXES
The list of suffixes of files that will be scanned for LaTeX
implicit dependencies (\include or \import files). The default list
is:

[".tex", ".ltx", ".latex"]

LDMODULE
The linker for building loadable modules. By default, this is the
same as $SHLINK.

LDMODULECOM
The command line for building loadable modules. On Mac OS X, this
uses the $LDMODULE, $LDMODULEFLAGS and $FRAMEWORKSFLAGS variables.
On other systems, this is the same as $SHLINK.

LDMODULECOMSTR
If set, the string displayed when building loadable modules. If not
set, then $LDMODULECOM (the command line) is displayed.

LDMODULEEMITTER
Contains the emitter specification for the LoadableModule builder.
The manpage section "Builder Objects" contains general information
on specifying emitters.

LDMODULEFLAGS
General user options passed to the linker for building loadable
modules.

LDMODULENOVERSIONSYMLINKS
Instructs the LoadableModule builder to not automatically create
symlinks for versioned modules. Defaults to $SHLIBNOVERSIONSYMLINKS

LDMODULEPREFIX
The prefix used for loadable module file names. On Mac OS X, this
is null; on other systems, this is the same as $SHLIBPREFIX.

_LDMODULESONAME
A macro that automatically generates loadable module's SONAME based
on $TARGET, $LDMODULEVERSION and $LDMODULESUFFIX. Used by
LoadableModule builder when the linker tool supports SONAME (e.g.
gnulink).

LDMODULESUFFIX
The suffix used for loadable module file names. On Mac OS X, this
is null; on other systems, this is the same as $SHLIBSUFFIX.

LDMODULEVERSION
When this construction variable is defined, a versioned loadable
module is created by LoadableModule builder. This activates the
$_LDMODULEVERSIONFLAGS and thus modifies the $LDMODULECOM as
required, adds the version number to the library name, and creates
the symlinks that are needed. $LDMODULEVERSION versions should
exist in the same format as $SHLIBVERSION.

_LDMODULEVERSIONFLAGS
This macro automatically introduces extra flags to $LDMODULECOM
when building versioned LoadableModule (that is when
$LDMODULEVERSION is set). _LDMODULEVERSIONFLAGS usually adds
$SHLIBVERSIONFLAGS and some extra dynamically generated options
(such as -Wl,-soname=$_LDMODULESONAME). It is unused by plain
(unversioned) loadable modules.

LDMODULEVERSIONFLAGS
Extra flags added to $LDMODULECOM when building versioned
LoadableModule. These flags are only used when $LDMODULEVERSION is
set.

LEX
The lexical analyzer generator.

LEXCOM
The command line used to call the lexical analyzer generator to
generate a source file.

LEXCOMSTR
The string displayed when generating a source file using the
lexical analyzer generator. If this is not set, then $LEXCOM (the
command line) is displayed.

env = Environment(LEXCOMSTR = "Lex'ing $TARGET from $SOURCES")

LEXFLAGS
General options passed to the lexical analyzer generator.

LEXUNISTD
Used only on windows environments to set a lex flag to prevent
'unistd.h' from being included. The default value is '--nounistd'.

_LIBDIRFLAGS
An automatically-generated construction variable containing the
linker command-line options for specifying directories to be
searched for library. The value of $_LIBDIRFLAGS is created by
respectively prepending and appending $LIBDIRPREFIX and
$LIBDIRSUFFIX to each directory in $LIBPATH.

LIBDIRPREFIX
The prefix used to specify a library directory on the linker
command line. This will be prepended to each directory in the
$LIBPATH construction variable when the $_LIBDIRFLAGS variable is
automatically generated.

LIBDIRSUFFIX
The suffix used to specify a library directory on the linker
command line. This will be appended to each directory in the
$LIBPATH construction variable when the $_LIBDIRFLAGS variable is
automatically generated.

LIBEMITTER
Contains the emitter specification for the StaticLibrary builder.
The manpage section "Builder Objects" contains general information
on specifying emitters.

_LIBFLAGS
An automatically-generated construction variable containing the
linker command-line options for specifying libraries to be linked
with the resulting target. The value of $_LIBFLAGS is created by
respectively prepending and appending $LIBLINKPREFIX and
$LIBLINKSUFFIX to each filename in $LIBS.

LIBLINKPREFIX
The prefix used to specify a library to link on the linker command
line. This will be prepended to each library in the $LIBS
construction variable when the $_LIBFLAGS variable is automatically
generated.

LIBLINKSUFFIX
The suffix used to specify a library to link on the linker command
line. This will be appended to each library in the $LIBS
construction variable when the $_LIBFLAGS variable is automatically
generated.

LIBPATH
The list of directories that will be searched for libraries
specified by the $LIBS construction variable. $LIBPATH should be a
list of path strings, or a single string, not a pathname list
joined by Python's os.sep.

Do not put library search directives directly into $LINKFLAGS or
$SHLINKFLAGS as the result will be non-portable.

Note: directory names in $LIBPATH will be looked-up relative to the
directory of the SConscript file when they are used in a command.
To force scons to look-up a directory relative to the root of the
source tree use the # prefix:

env = Environment(LIBPATH='#/libs')

The directory look-up can also be forced using the Dir function:

libs = Dir('libs')
env = Environment(LIBPATH=libs)

The directory list will be added to command lines through the
automatically-generated $_LIBDIRFLAGS construction variable, which
is constructed by respectively prepending and appending the values
of the $LIBDIRPREFIX and $LIBDIRSUFFIX construction variables to
each directory in $LIBPATH. Any command lines you define that need
the $LIBPATH directory list should include $_LIBDIRFLAGS:

env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")

LIBPREFIX
The prefix used for (static) library file names. A default value is
set for each platform (posix, win32, os2, etc.), but the value is
overridden by individual tools (ar, mslib, sgiar, sunar, tlib,
etc.) to reflect the names of the libraries they create.

LIBPREFIXES
A list of all legal prefixes for library file names. When searching
for library dependencies, SCons will look for files with these
prefixes, the base library name, and suffixes from the $LIBSUFFIXES
list.

LIBS
A list of one or more libraries that will be added to the link line
for linking with any executable program, shared library, or
loadable module created by the construction environment or
override.

String-valued library names should include only the library base
names, without prefixes such as lib or suffixes such as .so or
.dll. The library list will be added to command lines through the
automatically-generated $_LIBFLAGS construction variable which is
constructed by respectively prepending and appending the values of
the $LIBLINKPREFIX and $LIBLINKSUFFIX construction variables to
each library name in $LIBS. Library name strings should not include
a path component, instead the compiler will be directed to look for
libraries in the paths specified by $LIBPATH.

Any command lines you define that need the $LIBS library list
should include $_LIBFLAGS:

env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")

If you add a File object to the $LIBS list, the name of that file
will be added to $_LIBFLAGS, and thus to the link line, as-is,
without $LIBLINKPREFIX or $LIBLINKSUFFIX. For example:

env.Append(LIBS=File('/tmp/mylib.so'))

In all cases, scons will add dependencies from the executable
program to all the libraries in this list.

LIBSUFFIX
The suffix used for (static) library file names. A default value is
set for each platform (posix, win32, os2, etc.), but the value is
overridden by individual tools (ar, mslib, sgiar, sunar, tlib,
etc.) to reflect the names of the libraries they create.

LIBSUFFIXES
A list of all legal suffixes for library file names. When searching
for library dependencies, SCons will look for files with prefixes
from the $LIBPREFIXES list, the base library name, and these
suffixes.

LICENSE
The abbreviated name, preferably the SPDX code, of the license
under which this project is released (GPL-3.0, LGPL-2.1,
BSD-2-Clause etc.). See
http://www.opensource.org/licenses/alphabetical[4] for a list of
license names and SPDX codes.

See the Package builder.

LINESEPARATOR
The separator used by the Substfile and Textfile builders. This
value is used between sources when constructing the target. It
defaults to the current system line separator.

LINGUAS_FILE
The $LINGUAS_FILE defines file(s) containing list of additional
linguas to be processed by POInit, POUpdate or MOFiles builders. It
also affects Translate builder. If the variable contains a string,
it defines name of the list file. The $LINGUAS_FILE may be a list
of file names as well. If $LINGUAS_FILE is set to True (or non-zero
numeric value), the list will be read from default file named
LINGUAS.

LINK
The linker. See also $SHLINK for linking shared objects.

On POSIX systems (those using the link tool), you should normally
not change this value as it defaults to a "smart" linker tool which
selects a compiler driver matching the type of source files in use.
So for example, if you set $CXX to a specific compiler name, and
are compiling C++ sources, the smartlink function will
automatically select the same compiler for linking.

LINKCOM
The command line used to link object files into an executable. See
also $SHLINKCOM for linking shared objects.

LINKCOMSTR
If set, the string displayed when object files are linked into an
executable. If not set, then $LINKCOM (the command line) is
displayed. See also $SHLINKCOMSTR. for linking shared objects.

env = Environment(LINKCOMSTR = "Linking $TARGET")

LINKFLAGS
General user options passed to the linker. Note that this variable
should not contain -l (or similar) options for linking with the
libraries listed in $LIBS, nor -L (or similar) library search path
options that scons generates automatically from $LIBPATH. See
$_LIBFLAGS above, for the variable that expands to library-link
options, and $_LIBDIRFLAGS above, for the variable that expands to
library search path options. See also $SHLINKFLAGS. for linking
shared objects.

M4
The M4 macro preprocessor.

M4COM
The command line used to pass files through the M4 macro
preprocessor.

M4COMSTR
The string displayed when a file is passed through the M4 macro
preprocessor. If this is not set, then $M4COM (the command line) is
displayed.

M4FLAGS
General options passed to the M4 macro preprocessor.

MAKEINDEX
The makeindex generator for the TeX formatter and typesetter and
the LaTeX structured formatter and typesetter.

MAKEINDEXCOM
The command line used to call the makeindex generator for the TeX
formatter and typesetter and the LaTeX structured formatter and
typesetter.

MAKEINDEXCOMSTR
The string displayed when calling the makeindex generator for the
TeX formatter and typesetter and the LaTeX structured formatter and
typesetter. If this is not set, then $MAKEINDEXCOM (the command
line) is displayed.

MAKEINDEXFLAGS
General options passed to the makeindex generator for the TeX
formatter and typesetter and the LaTeX structured formatter and
typesetter.

MAXLINELENGTH
The maximum number of characters allowed on an external command
line. On Win32 systems, link lines longer than this many characters
are linked via a temporary file name.

MIDL
The Microsoft IDL compiler.

MIDLCOM
The command line used to pass files to the Microsoft IDL compiler.

MIDLCOMSTR
The string displayed when the Microsoft IDL compiler is called. If
this is not set, then $MIDLCOM (the command line) is displayed.

MIDLFLAGS
General options passed to the Microsoft IDL compiler.

MOSUFFIX
Suffix used for MO files (default: '.mo'). See msgfmt tool and
MOFiles builder.

MSGFMT
Absolute path to msgfmt(1) binary, found by Detect(). See msgfmt
tool and MOFiles builder.

MSGFMTCOM
Complete command line to run msgfmt(1) program. See msgfmt tool and
MOFiles builder.

MSGFMTCOMSTR
String to display when msgfmt(1) is invoked (default: '', which
means ``print $MSGFMTCOM''). See msgfmt tool and MOFiles builder.

MSGFMTFLAGS
Additional flags to msgfmt(1). See msgfmt tool and MOFiles builder.

MSGINIT
Path to msginit(1) program (found via Detect()). See msginit tool
and POInit builder.

MSGINITCOM
Complete command line to run msginit(1) program. See msginit tool
and POInit builder.

MSGINITCOMSTR
String to display when msginit(1) is invoked (default: '', which
means ``print $MSGINITCOM''). See msginit tool and POInit builder.

MSGINITFLAGS
List of additional flags to msginit(1) (default: []). See msginit
tool and POInit builder.

_MSGINITLOCALE
Internal ``macro''. Computes locale (language) name based on target
filename (default: '${TARGET.filebase}').

See msginit tool and POInit builder.

MSGMERGE
Absolute path to msgmerge(1) binary as found by Detect(). See
msgmerge tool and POUpdate builder.

MSGMERGECOM
Complete command line to run msgmerge(1) command. See msgmerge tool
and POUpdate builder.

MSGMERGECOMSTR
String to be displayed when msgmerge(1) is invoked (default: '',
which means ``print $MSGMERGECOM''). See msgmerge tool and POUpdate
builder.

MSGMERGEFLAGS
Additional flags to msgmerge(1) command. See msgmerge tool and
POUpdate builder.

MSSDK_DIR
The directory containing the Microsoft SDK (either Platform SDK or
Windows SDK) to be used for compilation.

MSSDK_VERSION
The version string of the Microsoft SDK (either Platform SDK or
Windows SDK) to be used for compilation. Supported versions include
6.1, 6.0A, 6.0, 2003R2 and 2003R1.

MSVC_BATCH
When set to any true value, specifies that SCons should batch
compilation of object files when calling the Microsoft Visual C/C++
compiler. All compilations of source files from the same source
directory that generate target files in a same output directory and
were configured in SCons using the same construction environment
will be built in a single call to the compiler. Only source files
that have changed since their object files were built will be
passed to each compiler invocation (via the $CHANGED_SOURCES
construction variable). Any compilations where the object (target)
file base name (minus the .obj) does not match the source file base
name will be compiled separately.

MSVC_USE_SCRIPT
Use a batch script to set up the Microsoft Visual C++ compiler.

If set to the name of a Visual Studio .bat file (e.g. vcvars.bat),
SCons will run that batch file instead of the auto-detected one,
and extract the relevant variables from the result (typically
%INCLUDE%, %LIB%, and %PATH%) for supplying to the build. This can
be useful to force the use of a compiler version that SCons does
not detect.

Setting $MSVC_USE_SCRIPT to None bypasses the Visual Studio
autodetection entirely; use this if you are running SCons in a
Visual Studio cmd window and importing the shell's environment
variables - that is, if you are sure everything is set correctly
already and you don't want SCons to change anything.

$MSVC_USE_SCRIPT overrides $MSVC_VERSION and $TARGET_ARCH.

MSVC_UWP_APP
Build libraries for a Universal Windows Platform (UWP) Application.

If $MSVC_UWP_APP is set, the Visual C++ environment will be set up
to point to the Windows Store compatible libraries and Visual C++
runtimes. In doing so, any libraries that are built will be able to
be used in a UWP App and published to the Windows Store. This flag
will only have an effect with Visual Studio 2015 or later. This
variable must be passed as an argument to the Environment()
constructor; setting it later has no effect.

Valid values are '1' or '0'

MSVC_VERSION
Sets the preferred version of Microsoft Visual C/C++ to use.

If $MSVC_VERSION is not set, SCons will (by default) select the
latest version of Visual C/C++ installed on your system. If the
specified version isn't installed, tool initialization will fail.
This variable must be passed as an argument to the Environment
constructor; setting it later has no effect.

Valid values for Windows are 14.2, 14.1, 14.1Exp, 14.0, 14.0Exp,
12.0, 12.0Exp, 11.0, 11.0Exp, 10.0, 10.0Exp, 9.0, 9.0Exp, 8.0,
8.0Exp, 7.1, 7.0, and 6.0. Versions ending in Exp refer to
"Express" or "Express for Desktop" editions.

MSVS
When the Microsoft Visual Studio tools are initialized, they set up
this dictionary with the following keys:

VERSION
the version of MSVS being used (can be set via $MSVS_VERSION)

VERSIONS
the available versions of MSVS installed

VCINSTALLDIR
installed directory of Visual C++

VSINSTALLDIR
installed directory of Visual Studio

FRAMEWORKDIR
installed directory of the .NET framework

FRAMEWORKVERSIONS
list of installed versions of the .NET framework, sorted latest
to oldest.

FRAMEWORKVERSION
latest installed version of the .NET framework

FRAMEWORKSDKDIR
installed location of the .NET SDK.

PLATFORMSDKDIR
installed location of the Platform SDK.

PLATFORMSDK_MODULES
dictionary of installed Platform SDK modules, where the
dictionary keys are keywords for the various modules, and the
values are 2-tuples where the first is the release date, and
the second is the version number.

If a value is not set, it was not available in the registry.

MSVS_ARCH
Sets the architecture for which the generated project(s) should
build.

The default value is x86. amd64 is also supported by SCons for
most Visual Studio versions. Since Visual Studio 2015 arm is
supported, and since Visual Studio 2017 arm64 is supported. Trying
to set $MSVS_ARCH to an architecture that's not supported for a
given Visual Studio version will generate an error.

MSVS_PROJECT_GUID
The string placed in a generated Microsoft Visual Studio project
file as the value of the ProjectGUID attribute. There is no default
value. If not defined, a new GUID is generated.

MSVS_SCC_AUX_PATH
The path name placed in a generated Microsoft Visual Studio project
file as the value of the SccAuxPath attribute if the
MSVS_SCC_PROVIDER construction variable is also set. There is no
default value.

MSVS_SCC_CONNECTION_ROOT
The root path of projects in your SCC workspace, i.e the path under
which all project and solution files will be generated. It is used
as a reference path from which the relative paths of the generated
Microsoft Visual Studio project and solution files are computed.
The relative project file path is placed as the value of the
SccLocalPath attribute of the project file and as the values of the
SccProjectFilePathRelativizedFromConnection[i] (where [i] ranges
from 0 to the number of projects in the solution) attributes of the
GlobalSection(SourceCodeControl) section of the Microsoft Visual
Studio solution file. Similarly the relative solution file path is
placed as the values of the SccLocalPath[i] (where [i] ranges from
0 to the number of projects in the solution) attributes of the
GlobalSection(SourceCodeControl) section of the Microsoft Visual
Studio solution file. This is used only if the MSVS_SCC_PROVIDER
construction variable is also set. The default value is the current
working directory.

MSVS_SCC_PROJECT_NAME
The project name placed in a generated Microsoft Visual Studio
project file as the value of the SccProjectName attribute if the
MSVS_SCC_PROVIDER construction variable is also set. In this case
the string is also placed in the SccProjectName0 attribute of the
GlobalSection(SourceCodeControl) section of the Microsoft Visual
Studio solution file. There is no default value.

MSVS_SCC_PROVIDER
The string placed in a generated Microsoft Visual Studio project
file as the value of the SccProvider attribute. The string is also
placed in the SccProvider0 attribute of the
GlobalSection(SourceCodeControl) section of the Microsoft Visual
Studio solution file. There is no default value.

MSVS_VERSION
Sets the preferred version of Microsoft Visual Studio to use.

If $MSVS_VERSION is not set, SCons will (by default) select the
latest version of Visual Studio installed on your system. So, if
you have version 6 and version 7 (MSVS .NET) installed, it will
prefer version 7. You can override this by specifying the
MSVS_VERSION variable in the Environment initialization, setting it
to the appropriate version ('6.0' or '7.0', for example). If the
specified version isn't installed, tool initialization will fail.

This is obsolete: use $MSVC_VERSION instead. If $MSVS_VERSION is
set and $MSVC_VERSION is not, $MSVC_VERSION will be set
automatically to $MSVS_VERSION. If both are set to different
values, scons will raise an error.

MSVSBUILDCOM
The build command line placed in a generated Microsoft Visual
Studio project file. The default is to have Visual Studio invoke
SCons with any specified build targets.

MSVSCLEANCOM
The clean command line placed in a generated Microsoft Visual
Studio project file. The default is to have Visual Studio invoke
SCons with the -c option to remove any specified targets.

MSVSENCODING
The encoding string placed in a generated Microsoft Visual Studio
project file. The default is encoding Windows-1252.

MSVSPROJECTCOM
The action used to generate Microsoft Visual Studio project files.

MSVSPROJECTSUFFIX
The suffix used for Microsoft Visual Studio project (DSP) files.
The default value is .vcproj when using Visual Studio version 7.x
(.NET) or later version, and .dsp when using earlier versions of
Visual Studio.

MSVSREBUILDCOM
The rebuild command line placed in a generated Microsoft Visual
Studio project file. The default is to have Visual Studio invoke
SCons with any specified rebuild targets.

MSVSSCONS
The SCons used in generated Microsoft Visual Studio project files.
The default is the version of SCons being used to generate the
project file.

MSVSSCONSCOM
The default SCons command used in generated Microsoft Visual Studio
project files.

MSVSSCONSCRIPT
The sconscript file (that is, SConstruct or SConscript file) that
will be invoked by Visual Studio project files (through the
$MSVSSCONSCOM variable). The default is the same sconscript file
that contains the call to MSVSProject to build the project file.

MSVSSCONSFLAGS
The SCons flags used in generated Microsoft Visual Studio project
files.

MSVSSOLUTIONCOM
The action used to generate Microsoft Visual Studio solution files.

MSVSSOLUTIONSUFFIX
The suffix used for Microsoft Visual Studio solution (DSW) files.
The default value is .sln when using Visual Studio version 7.x
(.NET), and .dsw when using earlier versions of Visual Studio.

MT
The program used on Windows systems to embed manifests into DLLs
and EXEs. See also $WINDOWS_EMBED_MANIFEST.

MTEXECOM
The Windows command line used to embed manifests into executables.
See also $MTSHLIBCOM.

MTFLAGS
Flags passed to the $MT manifest embedding program (Windows only).

MTSHLIBCOM
The Windows command line used to embed manifests into shared
libraries (DLLs). See also $MTEXECOM.

MWCW_VERSION
The version number of the MetroWerks CodeWarrior C compiler to be
used.

MWCW_VERSIONS
A list of installed versions of the MetroWerks CodeWarrior C
compiler on this system.

NAME
Specfies the name of the project to package.

See the Package builder.

NINJA_ALIAS_NAME
Name of the Alias() which is will cause SCons to create the
ninja.build file, and then (optionally) run ninja.

NINJA_COMPDB_EXPAND
Boolean value (True|False) to instruct ninja to expand the command
line arguments normally put into response files. This prevents
lines in the compilation database like "gcc @rsp_file" and instead
yields "gcc -c -o myfile.o myfile.c -Ia -DXYZ"

Ninja's compdb tool added the "-x" flag in Ninja V1.9.0

NINJA_DIR
This propagates directly into the generated ninja.build file. From
Ninja's docs: builddir A directory for some Ninja output files. ...
(You can also store other build output in this directory.)

NINJA_DISABLE_AUTO_RUN
Boolean (True|False). Default: False When True, SCons will not run
ninja automatically after creating the ninja.build file. If not
set, this will be set to True if "--disable_execute_ninja" or
SetOption('disable_execute_ninja', True)

NINJA_ENV_VAR_CACHE
A string that sets the environment for any environment variables
that differ between the OS environment and the SCons command ENV.
It will be compatible with the default shell of the operating
system. If not explicitly specified, SCons will generate this
dynamically from the Environment()'s 'ENV' "env['ENV']" where those
values differ from the existing shell..

NINJA_FILE_NAME
The filename for the generated Ninja build file defaults to
ninja.build

NINJA_GENERATED_SOURCE_SUFFIXES
The list of source file suffixes which are generated by SCons build
steps. All source files which match these suffixes will be added to
the _generated_sources alias in the output ninja.build file. Then
all other source files will be made to depend on this in the
ninja.build file, forcing the generated sources to be built first.

NINJA_MSVC_DEPS_PREFIX
This propagates directly into the generated ninja.build file. From
Ninja's docs "defines the string which should be stripped from
msvc's /showIncludes output"

NINJA_POOL
Set the "ninja_pool" for this or all targets in scope for this env
var.

NINJA_REGENERATE_DEPS
A generator function used to create a ninja depsfile which includes
all the files which would require SCons to be invoked if they
change. Or a list of said files.

_NINJA_REGENERATE_DEPS_FUNC
Internal value used to specify the function to call with argument
env to generate the list of files which if changed would require
the ninja file to be regenerated.

NINJA_SYNTAX
Theres also NINJA_SYNTAX which is the path to a custom
ninja_syntax.py file which is used in generation. The tool
currently assumes you have ninja installed through pip, and grabs
the syntax file from that installation if none specified.

no_import_lib
When set to non-zero, suppresses creation of a corresponding
Windows static import lib by the SharedLibrary builder when used
with MinGW, Microsoft Visual Studio or Metrowerks. This also
suppresses creation of an export (.exp) file when using Microsoft
Visual Studio.

OBJPREFIX
The prefix used for (static) object file names.

OBJSUFFIX
The suffix used for (static) object file names.

PACKAGEROOT
Specifies the directory where all files in resulting archive will
be placed if applicable. The default value is "$NAME-$VERSION".

See the Package builder.

PACKAGETYPE
Selects the package type to build when using the Package builder.
May be a string or list of strings. See the docuentation for the
builder for the currently supported types.

$PACKAGETYPE may be overridden with the --package-type command line
option.

See the Package builder.

PACKAGEVERSION
The version of the package (not the underlying project). This is
currently only used by the rpm packager and should reflect changes
in the packaging, not the underlying project code itself.

See the Package builder.

PCH
The Microsoft Visual C++ precompiled header that will be used when
compiling object files. This variable is ignored by tools other
than Microsoft Visual C++. When this variable is defined SCons will
add options to the compiler command line to cause it to use the
precompiled header, and will also set up the dependencies for the
PCH file. Example:

env['PCH'] = 'StdAfx.pch'

PCHCOM
The command line used by the PCH builder to generated a precompiled
header.

PCHCOMSTR
The string displayed when generating a precompiled header. If this
is not set, then $PCHCOM (the command line) is displayed.

PCHPDBFLAGS
A construction variable that, when expanded, adds the /yD flag to
the command line only if the $PDB construction variable is set.

PCHSTOP
This variable specifies how much of a source file is precompiled.
This variable is ignored by tools other than Microsoft Visual C++,
or when the PCH variable is not being used. When this variable is
define it must be a string that is the name of the header that is
included at the end of the precompiled portion of the source files,
or the empty string if the "#pragma hrdstop" construct is being
used:

env['PCHSTOP'] = 'StdAfx.h'

PDB
The Microsoft Visual C++ PDB file that will store debugging
information for object files, shared libraries, and programs. This
variable is ignored by tools other than Microsoft Visual C++. When
this variable is defined SCons will add options to the compiler and
linker command line to cause them to generate external debugging
information, and will also set up the dependencies for the PDB
file. Example:

env['PDB'] = 'hello.pdb'

The Visual C++ compiler switch that SCons uses by default to
generate PDB information is /Z7. This works correctly with parallel
(-j) builds because it embeds the debug information in the
intermediate object files, as opposed to sharing a single PDB file
between multiple object files. This is also the only way to get
debug information embedded into a static library. Using the /Zi
instead may yield improved link-time performance, although parallel
builds will no longer work. You can generate PDB files with the /Zi
switch by overriding the default $CCPDBFLAGS variable; see the
entry for that variable for specific examples.

PDFLATEX
The pdflatex utility.

PDFLATEXCOM
The command line used to call the pdflatex utility.

PDFLATEXCOMSTR
The string displayed when calling the pdflatex utility. If this is
not set, then $PDFLATEXCOM (the command line) is displayed.

env = Environment(PDFLATEX;COMSTR = "Building $TARGET from LaTeX input $SOURCES")

PDFLATEXFLAGS
General options passed to the pdflatex utility.

PDFPREFIX
The prefix used for PDF file names.

PDFSUFFIX
The suffix used for PDF file names.

PDFTEX
The pdftex utility.

PDFTEXCOM
The command line used to call the pdftex utility.

PDFTEXCOMSTR
The string displayed when calling the pdftex utility. If this is
not set, then $PDFTEXCOM (the command line) is displayed.

env = Environment(PDFTEXCOMSTR = "Building $TARGET from TeX input $SOURCES")

PDFTEXFLAGS
General options passed to the pdftex utility.

PKGCHK
On Solaris systems, the package-checking program that will be used
(along with $PKGINFO) to look for installed versions of the Sun PRO
C++ compiler. The default is /usr/sbin/pgkchk.

PKGINFO
On Solaris systems, the package information program that will be
used (along with $PKGCHK) to look for installed versions of the Sun
PRO C++ compiler. The default is pkginfo.

PLATFORM
The name of the platform used to create the Environment. If no
platform is specified when the Environment is created, scons
autodetects the platform.

env = Environment(tools = [])
if env['PLATFORM'] == 'cygwin':
Tool('mingw')(env)
else:
Tool('msvc')(env)

POAUTOINIT
The $POAUTOINIT variable, if set to True (on non-zero numeric
value), let the msginit tool to automatically initialize missing PO
files with msginit(1). This applies to both, POInit and POUpdate
builders (and others that use any of them).

POCREATE_ALIAS
Common alias for all PO files created with POInit builder (default:
'po-create'). See msginit tool and POInit builder.

POSUFFIX
Suffix used for PO files (default: '.po') See msginit tool and
POInit builder.

POTDOMAIN
The $POTDOMAIN defines default domain, used to generate POT
filename as $POTDOMAIN.pot when no POT file name is provided by the
user. This applies to POTUpdate, POInit and POUpdate builders (and
builders, that use them, e.g. Translate). Normally (if $POTDOMAIN
is not defined), the builders use messages.pot as default POT file
name.

POTSUFFIX
Suffix used for PO Template files (default: '.pot'). See xgettext
tool and POTUpdate builder.

POTUPDATE_ALIAS
Name of the common phony target for all PO Templates created with
POUpdate (default: 'pot-update'). See xgettext tool and POTUpdate
builder.

POUPDATE_ALIAS
Common alias for all PO files being defined with POUpdate builder
(default: 'po-update'). See msgmerge tool and POUpdate builder.

PRINT_CMD_LINE_FUNC
A Python function used to print the command lines as they are
executed (assuming command printing is not disabled by the -q or -s
options or their equivalents). The function should take four
arguments: s, the command being executed (a string), target, the
target being built (file node, list, or string name(s)), source,
the source(s) used (file node, list, or string name(s)), and env,
the environment being used.

The function must do the printing itself. The default
implementation, used if this variable is not set or is None, is:

def print_cmd_line(s, target, source, env):
sys.stdout.write(s + "\n")

Here's an example of a more interesting function:

def print_cmd_line(s, target, source, env):
sys.stdout.write("Building %s -> %s...\n" %
(' and '.join([str(x) for x in source]),
' and '.join([str(x) for x in target])))
env=Environment(PRINT_CMD_LINE_FUNC=print_cmd_line)
env.Program('foo', 'foo.c')

This just prints "Building targetname from sourcename..." instead
of the actual commands. Such a function could also log the actual
commands to a log file, for example.

PROGEMITTER
Contains the emitter specification for the Program builder. The
manpage section "Builder Objects" contains general information on
specifying emitters.

PROGPREFIX
The prefix used for executable file names.

PROGSUFFIX
The suffix used for executable file names.

PSCOM
The command line used to convert TeX DVI files into a PostScript
file.

PSCOMSTR
The string displayed when a TeX DVI file is converted into a
PostScript file. If this is not set, then $PSCOM (the command line)
is displayed.

PSPREFIX
The prefix used for PostScript file names.

PSSUFFIX
The prefix used for PostScript file names.

QT_AUTOSCAN
Turn off scanning for mocable files. Use the Moc Builder to
explicitly specify files to run moc on.

QT_BINPATH
The path where the qt binaries are installed. The default value is
'$QTDIR/bin'.

QT_CPPPATH
The path where the qt header files are installed. The default value
is '$QTDIR/include'. Note: If you set this variable to None, the
tool won't change the $CPPPATH construction variable.

QT_DEBUG
Prints lots of debugging information while scanning for moc files.

QT_LIB
Default value is 'qt'. You may want to set this to 'qt-mt'. Note:
If you set this variable to None, the tool won't change the $LIBS
variable.

QT_LIBPATH
The path where the qt libraries are installed. The default value is
'$QTDIR/lib'. Note: If you set this variable to None, the tool
won't change the $LIBPATH construction variable.

QT_MOC
Default value is '$QT_BINPATH/moc'.

QT_MOCCXXPREFIX
Default value is ''. Prefix for moc output files, when source is a
cxx file.

QT_MOCCXXSUFFIX
Default value is '.moc'. Suffix for moc output files, when source
is a cxx file.

QT_MOCFROMCXXCOM
Command to generate a moc file from a cpp file.

QT_MOCFROMCXXCOMSTR
The string displayed when generating a moc file from a cpp file. If
this is not set, then $QT_MOCFROMCXXCOM (the command line) is
displayed.

QT_MOCFROMCXXFLAGS
Default value is '-i'. These flags are passed to moc, when moccing
a C++ file.

QT_MOCFROMHCOM
Command to generate a moc file from a header.

QT_MOCFROMHCOMSTR
The string displayed when generating a moc file from a cpp file. If
this is not set, then $QT_MOCFROMHCOM (the command line) is
displayed.

QT_MOCFROMHFLAGS
Default value is ''. These flags are passed to moc, when moccing a
header file.

QT_MOCHPREFIX
Default value is 'moc_'. Prefix for moc output files, when source
is a header.

QT_MOCHSUFFIX
Default value is '$CXXFILESUFFIX'. Suffix for moc output files,
when source is a header.

QT_UIC
Default value is '$QT_BINPATH/uic'.

QT_UICCOM
Command to generate header files from .ui files.

QT_UICCOMSTR
The string displayed when generating header files from .ui files.
If this is not set, then $QT_UICCOM (the command line) is
displayed.

QT_UICDECLFLAGS
Default value is ''. These flags are passed to uic, when creating a
a h file from a .ui file.

QT_UICDECLPREFIX
Default value is ''. Prefix for uic generated header files.

QT_UICDECLSUFFIX
Default value is '.h'. Suffix for uic generated header files.

QT_UICIMPLFLAGS
Default value is ''. These flags are passed to uic, when creating a
cxx file from a .ui file.

QT_UICIMPLPREFIX
Default value is 'uic_'. Prefix for uic generated implementation
files.

QT_UICIMPLSUFFIX
Default value is '$CXXFILESUFFIX'. Suffix for uic generated
implementation files.

QT_UISUFFIX
Default value is '.ui'. Suffix of designer input files.

QTDIR
The qt tool tries to take this from os.environ. It also initializes
all QT_* construction variables listed below. (Note that all paths
are constructed with python's os.path.join() method, but are listed
here with the '/' separator for easier reading.) In addition, the
construction environment variables $CPPPATH, $LIBPATH and $LIBS may
be modified and the variables $PROGEMITTER, $SHLIBEMITTER and
$LIBEMITTER are modified. Because the build-performance is affected
when using this tool, you have to explicitly specify it at
Environment creation:

Environment(tools=['default','qt'])

The qt tool supports the following operations:

Automatic moc file generation from header files. You do not have
to specify moc files explicitly, the tool does it for you. However,
there are a few preconditions to do so: Your header file must have
the same filebase as your implementation file and must stay in the
same directory. It must have one of the suffixes .h, .hpp, .H,
.hxx, .hh. You can turn off automatic moc file generation by
setting QT_AUTOSCAN to 0. See also the corresponding Moc() builder
method.

Automatic moc file generation from cxx files. As stated in the qt
documentation, include the moc file at the end of the cxx file.
Note that you have to include the file, which is generated by the
transformation ${QT_MOCCXXPREFIX}<basename>${QT_MOCCXXSUFFIX}, by
default <basename>.moc. A warning is generated after building the
moc file, if you do not include the correct file. If you are using
VariantDir, you may need to specify duplicate=1. You can turn off
automatic moc file generation by setting QT_AUTOSCAN to 0. See also
the corresponding Moc builder method.

Automatic handling of .ui files. The implementation files
generated from .ui files are handled much the same as yacc or lex
files. Each .ui file given as a source of Program, Library or
SharedLibrary will generate three files, the declaration file, the
implementation file and a moc file. Because there are also
generated headers, you may need to specify duplicate=1 in calls to
VariantDir. See also the corresponding Uic builder method.

RANLIB
The archive indexer.

RANLIBCOM
The command line used to index a static library archive.

RANLIBCOMSTR
The string displayed when a static library archive is indexed. If
this is not set, then $RANLIBCOM (the command line) is displayed.

env = Environment(RANLIBCOMSTR = "Indexing $TARGET")

RANLIBFLAGS
General options passed to the archive indexer.

RC
The resource compiler used to build a Microsoft Visual C++ resource
file.

RCCOM
The command line used to build a Microsoft Visual C++ resource
file.

RCCOMSTR
The string displayed when invoking the resource compiler to build a
Microsoft Visual C++ resource file. If this is not set, then $RCCOM
(the command line) is displayed.

RCFLAGS
The flags passed to the resource compiler by the RES builder.

RCINCFLAGS
An automatically-generated construction variable containing the
command-line options for specifying directories to be searched by
the resource compiler. The value of $RCINCFLAGS is created by
respectively prepending and appending $RCINCPREFIX and $RCINCSUFFIX
to the beginning and end of each directory in $CPPPATH.

RCINCPREFIX
The prefix (flag) used to specify an include directory on the
resource compiler command line. This will be prepended to the
beginning of each directory in the $CPPPATH construction variable
when the $RCINCFLAGS variable is expanded.

RCINCSUFFIX
The suffix used to specify an include directory on the resource
compiler command line. This will be appended to the end of each
directory in the $CPPPATH construction variable when the
$RCINCFLAGS variable is expanded.

RDirs
A function that converts a string into a list of Dir instances by
searching the repositories.

REGSVR
The program used on Windows systems to register a newly-built DLL
library whenever the SharedLibrary builder is passed a keyword
argument of register=True.

REGSVRCOM
The command line used on Windows systems to register a newly-built
DLL library whenever the SharedLibrary builder is passed a keyword
argument of register=True.

REGSVRCOMSTR
The string displayed when registering a newly-built DLL file. If
this is not set, then $REGSVRCOM (the command line) is displayed.

REGSVRFLAGS
Flags passed to the DLL registration program on Windows systems
when a newly-built DLL library is registered. By default, this
includes the /s that prevents dialog boxes from popping up and
requiring user attention.

RMIC
The Java RMI stub compiler.

RMICCOM
The command line used to compile stub and skeleton class files from
Java classes that contain RMI implementations. Any options
specified in the $RMICFLAGS construction variable are included on
this command line.

RMICCOMSTR
The string displayed when compiling stub and skeleton class files
from Java classes that contain RMI implementations. If this is not
set, then $RMICCOM (the command line) is displayed.

env = Environment(RMICCOMSTR = "Generating stub/skeleton class files $TARGETS from $SOURCES")

RMICFLAGS
General options passed to the Java RMI stub compiler.

RPATH
A list of paths to search for shared libraries when running
programs. Currently only used in the GNU (gnulink), IRIX (sgilink)
and Sun (sunlink) linkers. Ignored on platforms and toolchains that
don't support it. Note that the paths added to RPATH are not
transformed by scons in any way: if you want an absolute path, you
must make it absolute yourself.

_RPATH
An automatically-generated construction variable containing the
rpath flags to be used when linking a program with shared
libraries. The value of $_RPATH is created by respectively
prepending $RPATHPREFIX and appending $RPATHSUFFIX to the beginning
and end of each directory in $RPATH.

RPATHPREFIX
The prefix used to specify a directory to be searched for shared
libraries when running programs. This will be prepended to the
beginning of each directory in the $RPATH construction variable
when the $_RPATH variable is automatically generated.

RPATHSUFFIX
The suffix used to specify a directory to be searched for shared
libraries when running programs. This will be appended to the end
of each directory in the $RPATH construction variable when the
$_RPATH variable is automatically generated.

RPCGEN
The RPC protocol compiler.

RPCGENCLIENTFLAGS
Options passed to the RPC protocol compiler when generating client
side stubs. These are in addition to any flags specified in the
$RPCGENFLAGS construction variable.

RPCGENFLAGS
General options passed to the RPC protocol compiler.

RPCGENHEADERFLAGS
Options passed to the RPC protocol compiler when generating a
header file. These are in addition to any flags specified in the
$RPCGENFLAGS construction variable.

RPCGENSERVICEFLAGS
Options passed to the RPC protocol compiler when generating server
side stubs. These are in addition to any flags specified in the
$RPCGENFLAGS construction variable.

RPCGENXDRFLAGS
Options passed to the RPC protocol compiler when generating XDR
routines. These are in addition to any flags specified in the
$RPCGENFLAGS construction variable.

SCANNERS
A list of the available implicit dependency scanners. New file
scanners may be added by appending to this list, although the more
flexible approach is to associate scanners with a specific Builder.
See the manpage sections "Builder Objects" and "Scanner Objects"
for more information.

SCONS_HOME
The (optional) path to the SCons library directory, initialized
from the external environment. If set, this is used to construct a
shorter and more efficient search path in the $MSVSSCONS command
line executed from Microsoft Visual Studio project files.

SHCC
The C compiler used for generating shared-library objects. See also
$CC for compiling to static objects.

SHCCCOM
The command line used to compile a C source file to a
shared-library object file. Any options specified in the $SHCFLAGS,
$SHCCFLAGS and $CPPFLAGS construction variables are included on
this command line. See also $CCCOM for compiling to static objects.

SHCCCOMSTR
If set, the string displayed when a C source file is compiled to a
shared object file. If not set, then $SHCCCOM (the command line) is
displayed. See also $CCCOMSTR for compiling to static objects.

env = Environment(SHCCCOMSTR = "Compiling shared object $TARGET")

SHCCFLAGS
Options that are passed to the C and C++ compilers to generate
shared-library objects. See also $CCFLAGS for compiling to static
objects.

SHCFLAGS
Options that are passed to the C compiler (only; not C++) to
generate shared-library objects. See also $CFLAGS for compiling to
static objects.

SHCXX
The C++ compiler used for generating shared-library objects. See
also $CXX for compiling to static objects.

SHCXXCOM
The command line used to compile a C++ source file to a
shared-library object file. Any options specified in the
$SHCXXFLAGS and $CPPFLAGS construction variables are included on
this command line. See also $CXXCOM for compiling to static
objects.

SHCXXCOMSTR
If set, the string displayed when a C++ source file is compiled to
a shared object file. If not set, then $SHCXXCOM (the command line)
is displayed. See also $CXXCOMSTR for compiling to static objects.

env = Environment(SHCXXCOMSTR = "Compiling shared object $TARGET")

SHCXXFLAGS
Options that are passed to the C++ compiler to generate
shared-library objects. See also $CXXFLAGS for compiling to static
objects.

SHDC
The name of the compiler to use when compiling D source destined to
be in a shared objects. See also $DC for compiling to static
objects.

SHDCOM
The command line to use when compiling code to be part of shared
objects. See also $DCOM for compiling to static objects.

SHDCOMSTR
If set, the string displayed when a D source file is compiled to a
(shared) object file. If not set, then $SHDCOM (the command line)
is displayed. See also $DCOMSTR for compiling to static objects.

SHDLIBVERSIONFLAGS
Extra flags added to $SHDLINKCOM when building versioned
SharedLibrary. These flags are only used when $SHLIBVERSION is set.

SHDLINK
The linker to use when creating shared objects for code bases
include D sources. See also $DLINK for linking static objects.

SHDLINKCOM
The command line to use when generating shared objects. See also
$DLINKCOM for linking static objects.

SHDLINKFLAGS
The list of flags to use when generating a shared object. See also
$DLINKFLAGS for linking static objects.

SHELL
A string naming the shell program that will be passed to the $SPAWN
function. See the $SPAWN construction variable for more
information.

SHF03
The Fortran 03 compiler used for generating shared-library objects.
You should normally set the $SHFORTRAN variable, which specifies
the default Fortran compiler for all Fortran versions. You only
need to set $SHF03 if you need to use a specific compiler or
compiler version for Fortran 03 files.

SHF03COM
The command line used to compile a Fortran 03 source file to a
shared-library object file. You only need to set $SHF03COM if you
need to use a specific command line for Fortran 03 files. You
should normally set the $SHFORTRANCOM variable, which specifies the
default command line for all Fortran versions.

SHF03COMSTR
If set, the string displayed when a Fortran 03 source file is
compiled to a shared-library object file. If not set, then
$SHF03COM or $SHFORTRANCOM (the command line) is displayed.

SHF03FLAGS
Options that are passed to the Fortran 03 compiler to generated
shared-library objects. You only need to set $SHF03FLAGS if you
need to define specific user options for Fortran 03 files. You
should normally set the $SHFORTRANFLAGS variable, which specifies
the user-specified options passed to the default Fortran compiler
for all Fortran versions.

SHF03PPCOM
The command line used to compile a Fortran 03 source file to a
shared-library object file after first running the file through the
C preprocessor. Any options specified in the $SHF03FLAGS and
$CPPFLAGS construction variables are included on this command line.
You only need to set $SHF03PPCOM if you need to use a specific
C-preprocessor command line for Fortran 03 files. You should
normally set the $SHFORTRANPPCOM variable, which specifies the
default C-preprocessor command line for all Fortran versions.

SHF03PPCOMSTR
If set, the string displayed when a Fortran 03 source file is
compiled to a shared-library object file after first running the
file through the C preprocessor. If not set, then $SHF03PPCOM or
$SHFORTRANPPCOM (the command line) is displayed.

SHF08
The Fortran 08 compiler used for generating shared-library objects.
You should normally set the $SHFORTRAN variable, which specifies
the default Fortran compiler for all Fortran versions. You only
need to set $SHF08 if you need to use a specific compiler or
compiler version for Fortran 08 files.

SHF08COM
The command line used to compile a Fortran 08 source file to a
shared-library object file. You only need to set $SHF08COM if you
need to use a specific command line for Fortran 08 files. You
should normally set the $SHFORTRANCOM variable, which specifies the
default command line for all Fortran versions.

SHF08COMSTR
If set, the string displayed when a Fortran 08 source file is
compiled to a shared-library object file. If not set, then
$SHF08COM or $SHFORTRANCOM (the command line) is displayed.

SHF08FLAGS
Options that are passed to the Fortran 08 compiler to generated
shared-library objects. You only need to set $SHF08FLAGS if you
need to define specific user options for Fortran 08 files. You
should normally set the $SHFORTRANFLAGS variable, which specifies
the user-specified options passed to the default Fortran compiler
for all Fortran versions.

SHF08PPCOM
The command line used to compile a Fortran 08 source file to a
shared-library object file after first running the file through the
C preprocessor. Any options specified in the $SHF08FLAGS and
$CPPFLAGS construction variables are included on this command line.
You only need to set $SHF08PPCOM if you need to use a specific
C-preprocessor command line for Fortran 08 files. You should
normally set the $SHFORTRANPPCOM variable, which specifies the
default C-preprocessor command line for all Fortran versions.

SHF08PPCOMSTR
If set, the string displayed when a Fortran 08 source file is
compiled to a shared-library object file after first running the
file through the C preprocessor. If not set, then $SHF08PPCOM or
$SHFORTRANPPCOM (the command line) is displayed.

SHF77
The Fortran 77 compiler used for generating shared-library objects.
You should normally set the $SHFORTRAN variable, which specifies
the default Fortran compiler for all Fortran versions. You only
need to set $SHF77 if you need to use a specific compiler or
compiler version for Fortran 77 files.

SHF77COM
The command line used to compile a Fortran 77 source file to a
shared-library object file. You only need to set $SHF77COM if you
need to use a specific command line for Fortran 77 files. You
should normally set the $SHFORTRANCOM variable, which specifies the
default command line for all Fortran versions.

SHF77COMSTR
If set, the string displayed when a Fortran 77 source file is
compiled to a shared-library object file. If not set, then
$SHF77COM or $SHFORTRANCOM (the command line) is displayed.

SHF77FLAGS
Options that are passed to the Fortran 77 compiler to generated
shared-library objects. You only need to set $SHF77FLAGS if you
need to define specific user options for Fortran 77 files. You
should normally set the $SHFORTRANFLAGS variable, which specifies
the user-specified options passed to the default Fortran compiler
for all Fortran versions.

SHF77PPCOM
The command line used to compile a Fortran 77 source file to a
shared-library object file after first running the file through the
C preprocessor. Any options specified in the $SHF77FLAGS and
$CPPFLAGS construction variables are included on this command line.
You only need to set $SHF77PPCOM if you need to use a specific
C-preprocessor command line for Fortran 77 files. You should
normally set the $SHFORTRANPPCOM variable, which specifies the
default C-preprocessor command line for all Fortran versions.

SHF77PPCOMSTR
If set, the string displayed when a Fortran 77 source file is
compiled to a shared-library object file after first running the
file through the C preprocessor. If not set, then $SHF77PPCOM or
$SHFORTRANPPCOM (the command line) is displayed.

SHF90
The Fortran 90 compiler used for generating shared-library objects.
You should normally set the $SHFORTRAN variable, which specifies
the default Fortran compiler for all Fortran versions. You only
need to set $SHF90 if you need to use a specific compiler or
compiler version for Fortran 90 files.

SHF90COM
The command line used to compile a Fortran 90 source file to a
shared-library object file. You only need to set $SHF90COM if you
need to use a specific command line for Fortran 90 files. You
should normally set the $SHFORTRANCOM variable, which specifies the
default command line for all Fortran versions.

SHF90COMSTR
If set, the string displayed when a Fortran 90 source file is
compiled to a shared-library object file. If not set, then
$SHF90COM or $SHFORTRANCOM (the command line) is displayed.

SHF90FLAGS
Options that are passed to the Fortran 90 compiler to generated
shared-library objects. You only need to set $SHF90FLAGS if you
need to define specific user options for Fortran 90 files. You
should normally set the $SHFORTRANFLAGS variable, which specifies
the user-specified options passed to the default Fortran compiler
for all Fortran versions.

SHF90PPCOM
The command line used to compile a Fortran 90 source file to a
shared-library object file after first running the file through the
C preprocessor. Any options specified in the $SHF90FLAGS and
$CPPFLAGS construction variables are included on this command line.
You only need to set $SHF90PPCOM if you need to use a specific
C-preprocessor command line for Fortran 90 files. You should
normally set the $SHFORTRANPPCOM variable, which specifies the
default C-preprocessor command line for all Fortran versions.

SHF90PPCOMSTR
If set, the string displayed when a Fortran 90 source file is
compiled to a shared-library object file after first running the
file through the C preprocessor. If not set, then $SHF90PPCOM or
$SHFORTRANPPCOM (the command line) is displayed.

SHF95
The Fortran 95 compiler used for generating shared-library objects.
You should normally set the $SHFORTRAN variable, which specifies
the default Fortran compiler for all Fortran versions. You only
need to set $SHF95 if you need to use a specific compiler or
compiler version for Fortran 95 files.

SHF95COM
The command line used to compile a Fortran 95 source file to a
shared-library object file. You only need to set $SHF95COM if you
need to use a specific command line for Fortran 95 files. You
should normally set the $SHFORTRANCOM variable, which specifies the
default command line for all Fortran versions.

SHF95COMSTR
If set, the string displayed when a Fortran 95 source file is
compiled to a shared-library object file. If not set, then
$SHF95COM or $SHFORTRANCOM (the command line) is displayed.

SHF95FLAGS
Options that are passed to the Fortran 95 compiler to generated
shared-library objects. You only need to set $SHF95FLAGS if you
need to define specific user options for Fortran 95 files. You
should normally set the $SHFORTRANFLAGS variable, which specifies
the user-specified options passed to the default Fortran compiler
for all Fortran versions.

SHF95PPCOM
The command line used to compile a Fortran 95 source file to a
shared-library object file after first running the file through the
C preprocessor. Any options specified in the $SHF95FLAGS and
$CPPFLAGS construction variables are included on this command line.
You only need to set $SHF95PPCOM if you need to use a specific
C-preprocessor command line for Fortran 95 files. You should
normally set the $SHFORTRANPPCOM variable, which specifies the
default C-preprocessor command line for all Fortran versions.

SHF95PPCOMSTR
If set, the string displayed when a Fortran 95 source file is
compiled to a shared-library object file after first running the
file through the C preprocessor. If not set, then $SHF95PPCOM or
$SHFORTRANPPCOM (the command line) is displayed.

SHFORTRAN
The default Fortran compiler used for generating shared-library
objects.

SHFORTRANCOM
The command line used to compile a Fortran source file to a
shared-library object file.

SHFORTRANCOMSTR
If set, the string displayed when a Fortran source file is compiled
to a shared-library object file. If not set, then $SHFORTRANCOM
(the command line) is displayed.

SHFORTRANFLAGS
Options that are passed to the Fortran compiler to generate
shared-library objects.

SHFORTRANPPCOM
The command line used to compile a Fortran source file to a
shared-library object file after first running the file through the
C preprocessor. Any options specified in the $SHFORTRANFLAGS and
$CPPFLAGS construction variables are included on this command line.

SHFORTRANPPCOMSTR
If set, the string displayed when a Fortran source file is compiled
to a shared-library object file after first running the file
through the C preprocessor. If not set, then $SHFORTRANPPCOM (the
command line) is displayed.

SHLIBEMITTER
Contains the emitter specification for the SharedLibrary builder.
The manpage section "Builder Objects" contains general information
on specifying emitters.

SHLIBNOVERSIONSYMLINKS
Instructs the SharedLibrary builder to not create symlinks for
versioned shared libraries.

SHLIBPREFIX
The prefix used for shared library file names.

_SHLIBSONAME
A macro that automatically generates shared library's SONAME based
on $TARGET, $SHLIBVERSION and $SHLIBSUFFIX. Used by SharedLibrary
builder when the linker tool supports SONAME (e.g. gnulink).

SHLIBSUFFIX
The suffix used for shared library file names.

SHLIBVERSION
When this construction variable is defined, a versioned shared
library is created by the SharedLibrary builder. This activates the
$_SHLIBVERSIONFLAGS and thus modifies the $SHLINKCOM as required,
adds the version number to the library name, and creates the
symlinks that are needed. $SHLIBVERSION versions should exist as
alpha-numeric, decimal-delimited values as defined by the regular
expression "\w+[\.\w+]*". Example $SHLIBVERSION values include '1',
'1.2.3', and '1.2.gitaa412c8b'.

_SHLIBVERSIONFLAGS
This macro automatically introduces extra flags to $SHLINKCOM when
building versioned SharedLibrary (that is when $SHLIBVERSION is
set). _SHLIBVERSIONFLAGS usually adds $SHLIBVERSIONFLAGS and some
extra dynamically generated options (such as
-Wl,-soname=$_SHLIBSONAME. It is unused by "plain" (unversioned)
shared libraries.

SHLIBVERSIONFLAGS
Extra flags added to $SHLINKCOM when building versioned
SharedLibrary. These flags are only used when $SHLIBVERSION is set.

SHLINK
The linker for programs that use shared libraries. See also $LINK
for linking static objects.

On POSIX systems (those using the link tool), you should normally
not change this value as it defaults to a "smart" linker tool which
selects a compiler driver matching the type of source files in use.
So for example, if you set $SHCXX to a specific compiler name, and
are compiling C++ sources, the smartlink function will
automatically select the same compiler for linking.

SHLINKCOM
The command line used to link programs using shared libraries. See
also $LINKCOM for linking static objects.

SHLINKCOMSTR
The string displayed when programs using shared libraries are
linked. If this is not set, then $SHLINKCOM (the command line) is
displayed. See also $LINKCOMSTR for linking static objects.

env = Environment(SHLINKCOMSTR = "Linking shared $TARGET")

SHLINKFLAGS
General user options passed to the linker for programs using shared
libraries. Note that this variable should not contain -l (or
similar) options for linking with the libraries listed in $LIBS,
nor -L (or similar) include search path options that scons
generates automatically from $LIBPATH. See $_LIBFLAGS above, for
the variable that expands to library-link options, and
$_LIBDIRFLAGS above, for the variable that expands to library
search path options. See also $LINKFLAGS for linking static
objects.

SHOBJPREFIX
The prefix used for shared object file names.

SHOBJSUFFIX
The suffix used for shared object file names.

SONAME
Variable used to hard-code SONAME for versioned shared
library/loadable module.

env.SharedLibrary('test', 'test.c', SHLIBVERSION='0.1.2', SONAME='libtest.so.2')

The variable is used, for example, by gnulink linker tool.

SOURCE
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

SOURCE_URL
The URL (web address) of the location from which the project was
retrieved. This is used to fill in the Source: field in the
controlling information for Ipkg and RPM packages.

See the Package builder.

SOURCES
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

SOVERSION
This will construct the SONAME using on the base library name (test
in the example below) and use specified SOVERSION to create SONAME.

env.SharedLibrary('test', 'test.c', SHLIBVERSION='0.1.2', SOVERSION='2')

The variable is used, for example, by gnulink linker tool.

In the example above SONAME would be libtest.so.2 which would be a
symlink and point to libtest.so.0.1.2

SPAWN
A command interpreter function that will be called to execute
command line strings. The function must expect the following
arguments:

def spawn(shell, escape, cmd, args, env):

sh is a string naming the shell program to use. escape is a
function that can be called to escape shell special characters in
the command line. cmd is the path to the command to be executed.
args is the arguments to the command. env is a dictionary of the
environment variables in which the command should be executed.

STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME
When this variable is true, static objects and shared objects are
assumed to be the same; that is, SCons does not check for linking
static objects into a shared library.

SUBST_DICT
The dictionary used by the Substfile or Textfile builders for
substitution values. It can be anything acceptable to the dict()
constructor, so in addition to a dictionary, lists of tuples are
also acceptable.

SUBSTFILEPREFIX
The prefix used for Substfile file names, an empty string by
default.

SUBSTFILESUFFIX
The suffix used for Substfile file names, an empty string by
default.

SUMMARY
A short summary of what the project is about. This is used to fill
in the Summary: field in the controlling information for Ipkg and
RPM packages, and as the Description: field in MSI packages.

See the Package builder.

SWIG
The scripting language wrapper and interface generator.

SWIGCFILESUFFIX
The suffix that will be used for intermediate C source files
generated by the scripting language wrapper and interface
generator. The default value is _wrap$CFILESUFFIX. By default, this
value is used whenever the -c++ option is not specified as part of
the $SWIGFLAGS construction variable.

SWIGCOM
The command line used to call the scripting language wrapper and
interface generator.

SWIGCOMSTR
The string displayed when calling the scripting language wrapper
and interface generator. If this is not set, then $SWIGCOM (the
command line) is displayed.

SWIGCXXFILESUFFIX
The suffix that will be used for intermediate C++ source files
generated by the scripting language wrapper and interface
generator. The default value is _wrap$CFILESUFFIX. By default, this
value is used whenever the -c++ option is specified as part of the
$SWIGFLAGS construction variable.

SWIGDIRECTORSUFFIX
The suffix that will be used for intermediate C++ header files
generated by the scripting language wrapper and interface
generator. These are only generated for C++ code when the SWIG
'directors' feature is turned on. The default value is _wrap.h.

SWIGFLAGS
General options passed to the scripting language wrapper and
interface generator. This is where you should set -python, -perl5,
-tcl, or whatever other options you want to specify to SWIG. If you
set the -c++ option in this variable, scons will, by default,
generate a C++ intermediate source file with the extension that is
specified as the $CXXFILESUFFIX variable.

_SWIGINCFLAGS
An automatically-generated construction variable containing the
SWIG command-line options for specifying directories to be searched
for included files. The value of $_SWIGINCFLAGS is created by
respectively prepending and appending $SWIGINCPREFIX and
$SWIGINCSUFFIX to the beginning and end of each directory in
$SWIGPATH.

SWIGINCPREFIX
The prefix used to specify an include directory on the SWIG command
line. This will be prepended to the beginning of each directory in
the $SWIGPATH construction variable when the $_SWIGINCFLAGS
variable is automatically generated.

SWIGINCSUFFIX
The suffix used to specify an include directory on the SWIG command
line. This will be appended to the end of each directory in the
$SWIGPATH construction variable when the $_SWIGINCFLAGS variable is
automatically generated.

SWIGOUTDIR
Specifies the output directory in which the scripting language
wrapper and interface generator should place generated
language-specific files. This will be used by SCons to identify the
files that will be generated by the swig call, and translated into
the swig -outdir option on the command line.

SWIGPATH
The list of directories that the scripting language wrapper and
interface generate will search for included files. The SWIG
implicit dependency scanner will search these directories for
include files. The default value is an empty list.

Don't explicitly put include directory arguments in SWIGFLAGS; the
result will be non-portable and the directories will not be
searched by the dependency scanner. Note: directory names in
SWIGPATH will be looked-up relative to the SConscript directory
when they are used in a command. To force scons to look-up a
directory relative to the root of the source tree use #:

env = Environment(SWIGPATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(SWIGPATH=include)

The directory list will be added to command lines through the
automatically-generated $_SWIGINCFLAGS construction variable, which
is constructed by respectively prepending and appending the values
of the $SWIGINCPREFIX and $SWIGINCSUFFIX construction variables to
the beginning and end of each directory in $SWIGPATH. Any command
lines you define that need the SWIGPATH directory list should
include $_SWIGINCFLAGS:

env = Environment(SWIGCOM="my_swig -o $TARGET $_SWIGINCFLAGS $SOURCES")

SWIGVERSION
The version number of the SWIG tool.

TAR
The tar archiver.

TARCOM
The command line used to call the tar archiver.

TARCOMSTR
The string displayed when archiving files using the tar archiver.
If this is not set, then $TARCOM (the command line) is displayed.

env = Environment(TARCOMSTR = "Archiving $TARGET")

TARFLAGS
General options passed to the tar archiver.

TARGET
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

TARGET_ARCH
The name of the target hardware architecture for the compiled
objects created by this Environment. This defaults to the value of
HOST_ARCH, and the user can override it. Currently only set for
Win32.

Sets the target architecture for the Visual C++ compiler (i.e. the
arch of the binaries generated by the compiler). If not set,
default to $HOST_ARCH, or, if that is unset, to the architecture of
the running machine's OS (note that the python build or
architecture has no effect). This variable must be passed as an
argument to the Environment() constructor; setting it later has no
effect. This is currently only used on Windows, but in the future
it will be used on other OSes as well. If this is set and
$MSVC_VERSION is not set, this will search for all installed MSVC's
that support the $TARGET_ARCH, selecting the latest version for
use.

On Windows, valid target values are x86, arm, i386 for 32-bit
targets and amd64, arm64, em64t, x86_64 and ia64 (Itanium) for
64-bit targets. Note that not all target architectures are
supported for all Visual Studio / MSVC versions. Check the relevant
Microsoft documentation.

For example, if you want to compile 64-bit binaries, you would set
TARGET_ARCH='x86_64' in your SCons environment.

TARGET_OS
The name of the target operating system for the compiled objects
created by this Environment. This defaults to the value of HOST_OS,
and the user can override it. Currently only set for Win32.

TARGETS
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

TARSUFFIX
The suffix used for tar file names.

TEMPFILEARGESCFUNC
A default argument escape function is ``SCons.Subst.quote_spaces``.
If you need to apply extra operations on a command argument before
writing to a temporary file(fix Windows slashes, normalize paths,
etc.), please set `TEMPFILEARGESCFUNC` variable to a custom
function. Example::

import sys
import re
from SCons.Subst import quote_spaces

WINPATHSEP_RE = re.compile(r"\\([^\"'\\]|$)")

def tempfile_arg_esc_func(arg):
arg = quote_spaces(arg)
if sys.platform != "win32":
return arg
# GCC requires double Windows slashes, let's use UNIX separator
return WINPATHSEP_RE.sub(r"/\1", arg)

env["TEMPFILEARGESCFUNC"] = tempfile_arg_esc_func

TEMPFILEARGJOIN
The string (or character) to be used to join the arguments passed
to TEMPFILE when command line exceeds the limit set by
$MAXLINELENGTH. The default value is a space. However for MSVC,
MSLINK the default is a line seperator characters as defined by
os.linesep. Note this value is used literally and not expanded by
the subst logic.

TEMPFILEDIR
The directory to create the tempfile in.

TEMPFILEPREFIX
The prefix for a temporary file used to store lines lines longer
than $MAXLINELENGTH as operations which call out to a shell will
fail if the line is too long, which particularly impacts linking.
The default is '@', which works for the Microsoft and GNU
toolchains on Windows. Set this appropriately for other toolchains,
for example '-@' for the diab compiler or '-via' for ARM toolchain.

TEMPFILESUFFIX
The suffix used for the temporary file name used for long command
lines. The name should include the dot ('.') if one is wanted as it
will not be added automatically. The default is '.lnk'.

TEX
The TeX formatter and typesetter.

TEXCOM
The command line used to call the TeX formatter and typesetter.

TEXCOMSTR
The string displayed when calling the TeX formatter and typesetter.
If this is not set, then $TEXCOM (the command line) is displayed.

env = Environment(TEXCOMSTR = "Building $TARGET from TeX input $SOURCES")

TEXFLAGS
General options passed to the TeX formatter and typesetter.

TEXINPUTS
List of directories that the LaTeX program will search for include
directories. The LaTeX implicit dependency scanner will search
these directories for \include and \import files.

TEXTFILEPREFIX
The prefix used for Textfile file names, an empty string by
default.

TEXTFILESUFFIX
The suffix used for Textfile file names; .txt by default.

TOOLS
A list of the names of the Tool specifications that are part of
this construction environment.

UNCHANGED_SOURCES
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

UNCHANGED_TARGETS
A reserved variable name that may not be set or used in a
construction environment. (See the manpage section "Variable
Substitution" for more information).

VENDOR
The person or organization who supply the packaged software. This
is used to fill in the Vendor: field in the controlling information
for RPM packages, and the Manufacturer: field in the controlling
information for MSI packages.

See the Package builder.

VERSION
The version of the project, specified as a string.

See the Package builder.

VSWHERE
Specify the location of vswhere.exe.

The vswhere.exe executable is distributed with Microsoft Visual
Studio and Build Tools since the 2017 edition, but is also
available standalone. It provides full information about
installations of 2017 and later editions. With the -legacy
argument, vswhere.exe can detect installations of the 2010 through
2015 editions with limited data returned. If VSWHERE is set, SCons
will use that location.

Otherwise SCons will look in the following locations and set
VSWHERE to the path of the first vswhere.exe located.

o %ProgramFiles(x86)%\Microsoft Visual Studio\Installer

o %ProgramFiles%\Microsoft Visual Studio\Installer

o %ChocolateyInstall%\bin

Note that VSWHERE must be set at the same time or prior to any of
msvc, msvs , and/or mslink Tool being initialized. Either set it as
follows

env = Environment(VSWHERE='c:/my/path/to/vswhere')

or if your construction environment is created specifying an empty
tools list (or a list of tools which omits all of default, msvs,
msvc, and mslink), and also before env.Tool is called to
ininitialize any of those tools:

env = Environment(tools=[])
env['VSWHERE'] = r'c:/my/vswhere/install/location/vswhere.exe'
env.Tool('msvc')
env.Tool('mslink')
env.Tool('msvs')

WINDOWS_EMBED_MANIFEST
Set to True to embed the compiler-generated manifest (normally
${TARGET}.manifest) into all Windows executables and DLLs built
with this environment, as a resource during their link step. This
is done using $MT and $MTEXECOM and $MTSHLIBCOM. See also
$WINDOWS_INSERT_MANIFEST.

WINDOWS_INSERT_DEF
If set to true, a library build of a Windows shared library (.dll
file) will include a reference to the corresponding
module-definition file at the same time, if a module-definition
file is not already listed as a build target. The name of the
module-definition file will be constructed from the base name of
the library and the construction variables $WINDOWSDEFSUFFIX and
$WINDOWSDEFPREFIX. The default is to not add a module-definition
file. The module-definition file is not created by this directive,
and must be supplied by the developer.

WINDOWS_INSERT_MANIFEST
If set to true, scons will add the manifest file generated by
Microsoft Visual C++ 8.0 and later to the target list so SCons will
be aware they were generated. In the case of an executable, the
manifest file name is constructed using $WINDOWSPROGMANIFESTSUFFIX
and $WINDOWSPROGMANIFESTPREFIX. In the case of a shared library,
the manifest file name is constructed using
$WINDOWSSHLIBMANIFESTSUFFIX and $WINDOWSSHLIBMANIFESTPREFIX. See
also $WINDOWS_EMBED_MANIFEST.

WINDOWSDEFPREFIX
The prefix used for a Windows linker module-definition file name.
Defaults to empty.

WINDOWSDEFSUFFIX
The suffix used for a Windows linker module-definition file name.
Defaults to .def.

WINDOWSEXPPREFIX
The prefix used for Windows linker exports file names. Defaults to
empty.

WINDOWSEXPSUFFIX
The suffix used for Windows linker exports file names. Defaults to
.exp.

WINDOWSPROGMANIFESTPREFIX
The prefix used for executable program manifest files generated by
Microsoft Visual C/C++. Defaults to empty.

WINDOWSPROGMANIFESTSUFFIX
The suffix used for executable program manifest files generated by
Microsoft Visual C/C++. Defaults to .manifest.

WINDOWSSHLIBMANIFESTPREFIX
The prefix used for shared library manifest files generated by
Microsoft Visual C/C++. Defaults to empty.

WINDOWSSHLIBMANIFESTSUFFIX
The suffix used for shared library manifest files generated by
Microsoft Visual C/C++. Defaults to .manifest.

X_IPK_DEPENDS
This is used to fill in the Depends: field in the controlling
information for Ipkg packages.

See the Package builder.

X_IPK_DESCRIPTION
This is used to fill in the Description: field in the controlling
information for Ipkg packages. The default value is
"$SUMMARY\n$DESCRIPTION"

X_IPK_MAINTAINER
This is used to fill in the Maintainer: field in the controlling
information for Ipkg packages.

X_IPK_PRIORITY
This is used to fill in the Priority: field in the controlling
information for Ipkg packages.

X_IPK_SECTION
This is used to fill in the Section: field in the controlling
information for Ipkg packages.

X_MSI_LANGUAGE
This is used to fill in the Language: attribute in the controlling
information for MSI packages.

See the Package builder.

X_MSI_LICENSE_TEXT
The text of the software license in RTF format. Carriage return
characters will be replaced with the RTF equivalent \\par.

See the Package builder.

X_MSI_UPGRADE_CODE
TODO

X_RPM_AUTOREQPROV
This is used to fill in the AutoReqProv: field in the RPM .spec
file.

See the Package builder.

X_RPM_BUILD
internal, but overridable

X_RPM_BUILDREQUIRES
This is used to fill in the BuildRequires: field in the RPM .spec
file. Note this should only be used on a host managed by rpm as the
dependencies will not be resolvable at build time otherwise.

X_RPM_BUILDROOT
internal, but overridable

X_RPM_CLEAN
internal, but overridable

X_RPM_CONFLICTS
This is used to fill in the Conflicts: field in the RPM .spec file.

X_RPM_DEFATTR
This value is used as the default attributes for the files in the
RPM package. The default value is "(-,root,root)".

X_RPM_DISTRIBUTION
This is used to fill in the Distribution: field in the RPM .spec
file.

X_RPM_EPOCH
This is used to fill in the Epoch: field in the RPM .spec file.

X_RPM_EXCLUDEARCH
This is used to fill in the ExcludeArch: field in the RPM .spec
file.

X_RPM_EXLUSIVEARCH
This is used to fill in the ExclusiveArch: field in the RPM .spec
file.

X_RPM_EXTRADEFS
A list used to supply extra defintions or flags to be added to the
RPM .spec file. Each item is added as-is with a carriage return
appended. This is useful if some specific RPM feature not otherwise
anticipated by SCons needs to be turned on or off. Note if this
variable is omitted, SCons will by default supply the value
'%global debug_package %{nil}' to disable debug package generation.
To enable debug package generation, include this variable set
either to None, or to a custom list that does not include the
default line. Added in version 3.1.

env.Package(
NAME="foo",
...
X_RPM_EXTRADEFS=[
"%define _unpackaged_files_terminate_build 0"
"%define _missing_doc_files_terminate_build 0"
],
...
)

X_RPM_GROUP
This is used to fill in the Group: field in the RPM .spec file.

X_RPM_GROUP_lang
This is used to fill in the Group(lang): field in the RPM .spec
file. Note that lang is not literal and should be replaced by the
appropriate language code.

X_RPM_ICON
This is used to fill in the Icon: field in the RPM .spec file.

X_RPM_INSTALL
internal, but overridable

X_RPM_PACKAGER
This is used to fill in the Packager: field in the RPM .spec file.

X_RPM_POSTINSTALL
This is used to fill in the %post: section in the RPM .spec file.

X_RPM_POSTUNINSTALL
This is used to fill in the %postun: section in the RPM .spec file.

X_RPM_PREFIX
This is used to fill in the Prefix: field in the RPM .spec file.

X_RPM_PREINSTALL
This is used to fill in the %pre: section in the RPM .spec file.

X_RPM_PREP
internal, but overridable

X_RPM_PREUNINSTALL
This is used to fill in the %preun: section in the RPM .spec file.

X_RPM_PROVIDES
This is used to fill in the Provides: field in the RPM .spec file.

X_RPM_REQUIRES
This is used to fill in the Requires: field in the RPM .spec file.

X_RPM_SERIAL
This is used to fill in the Serial: field in the RPM .spec file.

X_RPM_URL
This is used to fill in the Url: field in the RPM .spec file.

XGETTEXT
Path to xgettext(1) program (found via Detect()). See xgettext tool
and POTUpdate builder.

XGETTEXTCOM
Complete xgettext command line. See xgettext tool and POTUpdate
builder.

XGETTEXTCOMSTR
A string that is shown when xgettext(1) command is invoked
(default: '', which means "print $XGETTEXTCOM"). See xgettext tool
and POTUpdate builder.

_XGETTEXTDOMAIN
Internal "macro". Generates xgettext domain name form source and
target (default: '${TARGET.filebase}').

XGETTEXTFLAGS
Additional flags to xgettext(1). See xgettext tool and POTUpdate
builder.

XGETTEXTFROM
Name of file containing list of xgettext(1)'s source files.
Autotools' users know this as POTFILES.in so they will in most
cases set XGETTEXTFROM="POTFILES.in" here. The $XGETTEXTFROM files
have same syntax and semantics as the well known GNU POTFILES.in.
See xgettext tool and POTUpdate builder.

_XGETTEXTFROMFLAGS
Internal "macro". Genrates list of -D<dir> flags from the
$XGETTEXTPATH list.

XGETTEXTFROMPREFIX
This flag is used to add single $XGETTEXTFROM file to xgettext(1)'s
commandline (default: '-f').

XGETTEXTFROMSUFFIX
(default: '')

XGETTEXTPATH
List of directories, there xgettext(1) will look for source files
(default: []).

Note
This variable works only together with $XGETTEXTFROM
See also xgettext tool and POTUpdate builder.

_XGETTEXTPATHFLAGS
Internal "macro". Generates list of -f<file> flags from
$XGETTEXTFROM.

XGETTEXTPATHPREFIX
This flag is used to add single search path to xgettext(1)'s
commandline (default: '-D').

XGETTEXTPATHSUFFIX
(default: '')

YACC
The parser generator.

YACCCOM
The command line used to call the parser generator to generate a
source file.

YACCCOMSTR
The string displayed when generating a source file using the parser
generator. If this is not set, then $YACCCOM (the command line) is
displayed.

env = Environment(YACCCOMSTR = "Yacc'ing $TARGET from $SOURCES")

YACCFLAGS
General options passed to the parser generator. If $YACCFLAGS
contains a -d option, SCons assumes that the call will also create
a .h file (if the yacc source file ends in a .y suffix) or a .hpp
file (if the yacc source file ends in a .yy suffix)

YACCHFILESUFFIX
The suffix of the C header file generated by the parser generator
when the -d option is used. Note that setting this variable does
not cause the parser generator to generate a header file with the
specified suffix, it exists to allow you to specify what suffix the
parser generator will use of its own accord. The default value is
.h.

YACCHXXFILESUFFIX
The suffix of the C++ header file generated by the parser generator
when the -d option is used. Note that setting this variable does
not cause the parser generator to generate a header file with the
specified suffix, it exists to allow you to specify what suffix the
parser generator will use of its own accord. The default value is
.hpp, except on Mac OS X, where the default is ${TARGET.suffix}.h.
because the default bison parser generator just appends .h to the
name of the generated C++ file.

YACCVCGFILESUFFIX
The suffix of the file containing the VCG grammar automaton
definition when the --graph= option is used. Note that setting this
variable does not cause the parser generator to generate a VCG file
with the specified suffix, it exists to allow you to specify what
suffix the parser generator will use of its own accord. The default
value is .vcg.

ZIP
The zip compression and file packaging utility.

ZIP_OVERRIDE_TIMESTAMP
An optional timestamp which overrides the last modification time of
the file when stored inside the Zip archive. This is a tuple of six
values: Year (>= 1980) Month (one-based) Day of month (one-based)
Hours (zero-based) Minutes (zero-based) Seconds (zero-based)

ZIPCOM
The command line used to call the zip utility, or the internal
Python function used to create a zip archive.

ZIPCOMPRESSION
The compression flag from the Python zipfile module used by the
internal Python function to control whether the zip archive is
compressed or not. The default value is zipfile.ZIP_DEFLATED, which
creates a compressed zip archive. This value has no effect if the
zipfile module is unavailable.

ZIPCOMSTR
The string displayed when archiving files using the zip utility. If
this is not set, then $ZIPCOM (the command line or internal Python
function) is displayed.

env = Environment(ZIPCOMSTR = "Zipping $TARGET")

ZIPFLAGS
General options passed to the zip utility.

ZIPROOT
An optional zip root directory (default empty). The filenames
stored in the zip file will be relative to this directory, if
given. Otherwise the filenames are relative to the current
directory of the command. For instance:

env = Environment()
env.Zip('foo.zip', 'subdir1/subdir2/file1', ZIPROOT='subdir1')

will produce a zip file foo.zip containing a file with the name
subdir2/file1 rather than subdir1/subdir2/file1.

ZIPSUFFIX
The suffix used for zip file names.

Configure Contexts
SCons supports a configure context, an integrated mechanism similar to
the various AC_CHECK macros in GNU Autoconf for testing the existence
of external items needed for the build, such as C header files,
libraries, etc. The mechanism is portable across platforms.

scons does not maintain an explicit cache of the tested values (this is
different than Autoconf), but uses its normal dependency tracking to
keep the checked values up to date. However, users may override this
behaviour with the --config command line option.

Configure(env, [custom_tests, conf_dir, log_file, config_h, clean,
help]), env.Configure([custom_tests, conf_dir, log_file, config_h,
clean, help])
Create a configure context, which tracks information discovered
while running tests. The context includes a local construction
environment (available as context.env) which is used when running
the tests and which can be updated with the check results. Only one
context may be active at a time (since 4.0, scons will raise an
exception on an attempt to create a new context when there is an
active context), but a new context can be created after the active
one is completed. For the global function form, the required env
describes the initial values for the context's local construction
environment; for the construction environment method form the
instance provides the values.

custom_tests specifies a dictionary containing custom tests (see
the section on custom tests below). The default value is None,
meaning no custom tests are added to the configure context.

conf_dir specifies a directory where the test cases are built. This
directory is not used for building normal targets. The default
value is "#/.sconf_temp".

log_file specifies a file which collects the output from commands
that are executed to check for the existence of header files,
libraries, etc. The default is "#/config.log". If you are using the
VariantDir function, you may want to specify a subdirectory under
your variant directory.

config_h specifies a C header file where the results of tests will
be written. The results will consist of lines like #define
HAVE_STDIO_H, #define HAVE_LIBM, etc. Customarily, the name chosen
is "config.h". The default is to not write a config_h file. You can
specify the same config_h file in multiple calls to Configure, in
which case SCons will concatenate all results in the specified
file. Note that SCons uses its normal dependency checking to decide
if it's necessary to rebuild the specified config_h file. This
means that the file is not necessarily re-built each time scons is
run, but is only rebuilt if its contents will have changed and some
target that depends on the config_h file is being built.

The clean and help arguments can be used to suppress execution of
the configuration tests when the -c/--clean or -H/-h/--help options
are used, respectively. The default behavior is always to execute
configure context tests, since the results of the tests may affect
the list of targets to be cleaned or the help text. If the
configure tests do not affect these, then you may add the
clean=False or help=False arguments (or both) to avoid unnecessary
test execution.

SConf.Finish(context), context.Finish()
This method must be called after configuration is done. Though
required, this is not enforced except if Configure is called again
while there is still an active context, in which case an exception
is raised. Finish returns the environment as modified during the
course of running the configuration checks. After this method is
called, no further checks can be performed with this configuration
context. However, you can create a new configure context to perform
additional checks.

Example of a typical Configure usage:

env = Environment()
conf = Configure(env)
if not conf.CheckCHeader("math.h"):
print("We really need math.h!")
Exit(1)
if conf.CheckLibWithHeader("qt", "qapp.h", "c++", "QApplication qapp(0,0);"):
# do stuff for qt - usage, e.g.
conf.env.Append(CPPDEFINES="WITH_QT")
env = conf.Finish()

A configure context has the following predefined methods which can be
used to perform checks. Where language is a required or optional
parameter, the choice can currently be C or C++. The spellings accepted
for C are "C" or "c"; for C++ the value can be "CXX", "cxx", "C++" or
"c++".

SConf.CheckHeader(context, header, [include_quotes, language]),
context.CheckHeader(header, [include_quotes, language])
Checks if header is usable in the specified language. header may
be a list, in which case the last item in the list is the header
file to be checked, and the previous list items are header files
whose #include lines should precede the header line being checked
for. The optional argument include_quotes must be a two character
string, where the first character denotes the opening quote and the
second character denotes the closing quote. By default, both
characters are " (double quote). The optional argument language
should be either C or C++ and selects the compiler to be used for
the check. Returns a boolean indicating success or failure.

SConf.CheckCHeader(context, header, [include_quotes]),
context.CheckCHeader(header, [include_quotes])
This is a wrapper around SConf.CheckHeader which checks if header
is usable in the C language. header may be a list, in which case
the last item in the list is the header file to be checked, and the
previous list items are header files whose #include lines should
precede the header line being checked for. The optional argument
include_quotes must be a two character string, where the first
character denotes the opening quote and the second character
denotes the closing quote. By default, both characters are "
(double quote). Returns a boolean indicating success or failure.

SConf.CheckCXXHeader(context, header, [include_quotes]),
context.CheckCXXHeader(header, [include_quotes])
This is a wrapper around SConf.CheckHeader which checks if header
is usable in the C++ language. header may be a list, in which case
the last item in the list is the header file to be checked, and the
previous list items are header files whose #include lines should
precede the header line being checked for. The optional argument
include_quotes must be a two character string, where the first
character denotes the opening quote and the second character
denotes the closing quote. By default, both characters are "
(double quote). Returns a boolean indicating success or failure.

SConf.CheckFunc(context, function_name, [header, language]),
context.CheckFunc(function_name, [header, language])
Checks if the specified C or C++ library function is available
based on the context's local environment settings (that is, using
the values of CFLAGS, CPPFLAGS, LIBS or other relevant construction
variables).

function_name is the name of the function to check for. The
optional header argument is a string that will be placed at the top
of the test file that will be compiled to check if the function
exists; the default is:

#ifdef __cplusplus
extern "C"
#endif
char function_name();

Returns an empty string on success, a string containing an error
message on failure.

SConf.CheckLib(context, [library, symbol, header, language,
autoadd=True]), context.CheckLib([library, symbol, header, language,
autoadd=True])
Checks if library provides symbol. If autoadd is true (the default)
and the library provides the specified symbol, appends the library
to the LIBS construction variable library may also be None (the
default), in which case symbol is checked with the current LIBS
variable, or a list of library names, in which case each library in
the list will be checked for symbol. If symbol is not set or is
None, then SConf.CheckLib just checks if you can link against the
specified library. Note though it is legal syntax, it would not be
very useful to call this method with library and symbol both
omitted or None. Returns a boolean indicating success or failure.

SConf.CheckLibWithHeader(context, library, header, language, [call,
autoadd=True]), context.CheckLibWithHeader(library, header, language,
[call, autoadd=True])
Provides a more sophisticated way to check against libraries then
the SConf.CheckLib call. library specifies the library or a list
of libraries to check. header specifies a header to check for.
header may be a list, in which case the last item in the list is
the header file to be checked, and the previous list items are
header files whose #include lines should precede the header line
being checked for. call can be any valid expression (with a
trailing ';'). If call is not set, the default simply checks that
you can link against the specified library. autoadd (default true)
specifies whether to add the library to the environment if the
check succeeds. Returns a boolean indicating success or failure.

SConf.CheckType(context, type_name, [includes, language]),
context.CheckType(type_name, [includes, language])
Checks for the existence of a type defined by typedef. type_name
specifies the typedef name to check for. includes is a string
containing one or more #include lines that will be inserted into
the program that will be run to test for the existence of the type.
Example:

sconf.CheckType('foo_type', '#include "my_types.h"', 'C++')

Returns an empty string on success, a string containing an error
message on failure.

SConf.CheckCC(context), context.CheckCC()
Checks whether the C compiler (as defined by the CC construction
variable) works by trying to compile a small source file. Returns a
boolean indicating success or failure.

By default, SCons only detects if there is a program with the
correct name, not if it is a functioning compiler.

This uses the exact same command as the one used by the object
builder for C source files, so it can be used to detect if a
particular compiler flag works or not.

SConf.CheckCXX(context), context.CheckCXX()
Checks whether the C++ compiler (as defined by the CXX construction
variable) works by trying to compile a small source file. By
default, SCons only detects if there is a program with the correct
name, not if it is a functioning compiler. Returns a boolean
indicating success or failure.

This uses the exact same command as the one used by the object
builder for C++ source files, so it can be used to detect if a
particular compiler flag works or not.

SConf.CheckSHCC(context), context.CheckSHCC()
Checks whether the shared-object C compiler (as defined by the SHCC
construction variable) works by trying to compile a small source
file. By default, SCons only detects if there is a program with the
correct name, not if it is a functioning compiler. Returns a
boolean indicating success or failure.

This uses the exact same command as the one used by the object
builder for C source file, so it can be used to detect if a
particular compiler flag works or not. This does not check whether
the object code can be used to build a shared library, only that
the compilation (not link) succeeds.

SConf.CheckSHCXX(context), context.CheckSHCXX()
Checks whether the shared-object C++ compiler (as defined by the
SHCXX construction variable) works by trying to compile a small
source file. By default, SCons only detects if there is a program
with the correct name, not if it is a functioning compiler. Returns
a boolean indicating success or failure.

This uses the exact same command as the one used by the object
builder for C++ source files, so it can be used to detect if a
particular compiler flag works or not. This does not check whether
the object code can be used to build a shared library, only that
the compilation (not link) succeeds.

SConf.CheckTypeSize(context, type_name, [header, language, expect]),
context.CheckTypeSize(type_name, [header, language, expect])
Checks for the size of a type defined by typedef. type_name
specifies the typedef name to check for. The optional header
argument is a string that will be placed at the top of the test
file that will be compiled to check if the type exists; the default
is empty. If the optional expect, is supplied, it should be an
integer size; CheckTypeSize will fail unless type_name is actually
that size. Returns the size in bytes, or zero if the type was not
found (or if the size did not match expect).

For example,

CheckTypeSize('short', expect=2)

will return the size 2 only if short is actually two bytes.

SConf.CheckDeclaration(context, symbol, [includes, language]),
context.CheckDeclaration(symbol, [includes, language])
Checks if the specified symbol is declared. includes is a string
containing one or more #include lines that will be inserted into
the program that will be run to test for the existence of the
symbol. Returns a boolean indicating success or failure.

SConf.Define(context, symbol, [value, comment]), context.Define(symbol,
[value, comment])
This function does not check for anything, but defines a
preprocessor symbol that will be added to the configuration header
file. It is the equivalent of AC_DEFINE, and defines the symbol
name with the optional value and the optional comment comment.

Define Examples:

env = Environment()
conf = Configure(env)

# Puts the following line in the config header file:
# #define A_SYMBOL
conf.Define("A_SYMBOL")

# Puts the following line in the config header file:
# #define A_SYMBOL 1
conf.Define("A_SYMBOL", 1)

Be careful about quoting string values, though:

env = Environment()
conf = Configure(env)

# Puts the following line in the config header file:
# #define A_SYMBOL YA
conf.Define("A_SYMBOL", "YA")

# Puts the following line in the config header file:
# #define A_SYMBOL "YA"
conf.Define("A_SYMBOL", '"YA"')

For comment:

env = Environment()
conf = Configure(env)

# Puts the following lines in the config header file:
# /* Set to 1 if you have a symbol */
# #define A_SYMBOL 1
conf.Define("A_SYMBOL", 1, "Set to 1 if you have a symbol")

You can define your own custom checks in addition to the predefined
checks. You pass a dictionary of these to the Configure function as the
custom_tests argument. This dictionary maps the names of the checks to
the user defined Python callables (either Python functions or class
instances implementing a __call__ method). Each custom check will be
called with a first argument of a CheckContext, instance followed by
the arguments, which must be supplied by the user of the check. A
CheckContext instance defines the following methods:

context.Message(text)
Displays a message, as an indicator of progess. text will be
displayed, e.g. Checking for library X.... Usually called before
the check is started.

context.Result(res)
Displays a "result" message, as an indicator of progress. res can
be either an integer or a string. If an integer, displays yes (if
res evaluates True) or no (if res evaluates False). If a string, it
is displayed as-is. Usually called after the check has completed.

context.TryCompile(text, extension='')
Checks if a file with the specified extension (e.g. '.c')
containing text can be compiled using the environment's Object
builder. Returns a boolean indicating success or failure.

context.TryLink(text, extension='')
Checks, if a file with the specified extension (e.g. '.c')
containing text can be compiled using the environment's Program
builder. Returns a boolean indicating success or failure.

context.TryRun(text, extension='')
Checks if a file with the specified extension (e.g. '.c')
containing text can be compiled using the environment's Program
builder. On success, the program is run. If the program executes
successfully (that is, its return status is 0), a tuple (1,
outputStr) is returned, where outputStr is the standard output of
the program. If the program fails execution (its return status is
non-zero), then (0, '') is returned.

context.TryAction(action, [text, extension=''])
Checks if the specified action with an optional source file
(contents text, extension extension) can be executed. action may
be anything which can be converted to a scons Action. On success,
(1, outputStr) is returned, where outputStr is the content of the
target file. On failure (0, '') is returned.

context.TryBuild(builder[, text, extension=''])
Low level implementation for testing specific builds; the methods
above are based on this method. Given the Builder instance builder
and the optional text of a source file with optional extension,
returns a boolean indicating success or failure. In addition,
context.lastTarget is set to the build target node if the build was
successful.

Example of implementing and using custom tests:

def CheckQt(context, qtdir):
context.Message( 'Checking for qt ...' )
lastLIBS = context.env['LIBS']
lastLIBPATH = context.env['LIBPATH']
lastCPPPATH= context.env['CPPPATH']
context.env.Append(LIBS='qt', LIBPATH=qtdir + '/lib', CPPPATH=qtdir + '/include')
ret = context.TryLink("""
#include <qapp.h>
int main(int argc, char **argv) {
QApplication qapp(argc, argv);
return 0;
}
""")
if not ret:
context.env.Replace(LIBS=lastLIBS, LIBPATH=lastLIBPATH, CPPPATH=lastCPPPATH)
context.Result( ret )
return ret

env = Environment()
conf = Configure(env, custom_tests={'CheckQt': CheckQt})
if not conf.CheckQt('/usr/lib/qt'):
print('We really need qt!')
Exit(1)
env = conf.Finish()

Command-Line Construction Variables
Often when building software, some variables need to be specified at
build time. For example, libraries needed for the build may be in
non-standard locations, or site-specific compiler options may need to
be passed to the compiler. SCons provides a Variables object to
support overriding construction variables with values obtained from
various sources, often from the command line:

scons VARIABLE=foo

The variable values can also be specified in a configuration file or an
SConscript file.

To obtain the object for manipulating values, call the Variables
function:

Variables([files, [args]])
If files is a file or list of files, those are executed as Python
scripts, and the values of (global) Python variables set in those
files are added as construction variables in the Default
Environment. If no files are specified, or the files argument is
None, then no files will be read (supplying None is necessary if
there are no files but you want to specify args as a positional
argument).

The following example file contents could be used to set an
alternative C compiler:

CC = 'my_cc'

If args is specified, it is a dictionary of values that will
override anything read from files. This is primarily intended to
pass the ARGUMENTS dictionary that holds variables specified on the
command line. Example:

vars = Variables('custom.py')
vars = Variables('overrides.py', ARGUMENTS)
vars = Variables(None, {FOO:'expansion', BAR:7})

Calling Variables with no arguments is equivalent to:

vars = Variables(files=None, args=ARGUMENTS)

Note that since the variables are eventually added as construction
variables, you should choose variable names which do not
unintentionally change pre-defined construction variables that your
project will make use of (see the section called "Construction
Variables").

Variables objects have the following methods:

vars.Add(key, [help, default, validator, converter])
Add a customizable construction variable to the Variables object.
key is the name of the variable. help is the help text for the
variable. default is the default value of the variable; if the
default value is None and there is no explicit value specified, the
construction variable will not be added to the construction
environment. If set, validator is called to validate the value of
the variable. A function supplied as a validator shall accept
arguments: key, value, and env. The recommended way to handle an
invalid value is to raise an exception (see example below). If set,
converter is called to convert the value before putting it in the
environment, and should take either a value, or the value and
environment, as parameters. The converter function must return a
value, which will be converted into a string before being validated
by the validator (if any) and then added to the construction
environment.

Examples:

vars.Add('CC', help='The C compiler')

def valid_color(key, val, env):
if not val in ['red', 'blue', 'yellow']:
raise Exception("Invalid color value '%s'" % val)

vars.Add('COLOR', validator=valid_color)

vars.AddVariables(args)
A convenience method that adds multiple customizable construction
variables to a Variables object in one call; equivalent to calling
Add multiple times. The args are tuples (or lists) that contain the
arguments for an individual call to the Add method. Since tuples
are not Python mappings, the arguments cannot use the keyword form,
but rather are positional arguments as documented for Add: a
required name, the rest optional but must be in the specified in
order if used.

opt.AddVariables(
("debug", "", 0),
("CC", "The C compiler"),
("VALIDATE", "An option for testing validation", "notset", validator, None),
)

vars.Update(env, [args])
Update a construction environment env with the customized
construction variables . Any specified variables that are not
configured for the Variables object will be saved and may be
retrieved using the UnknownVariables method, below.

Normally this method is not called directly, but rather invoked
indirectly by passing the Variables object to the Environment
function:

env = Environment(variables=vars)

vars.UnknownVariables()
Returns a dictionary containing any variables that were specified
either in the files or the dictionary with which the Variables
object was initialized, but for which the Variables object was not
configured.

env = Environment(variables=vars)
for key, value in vars.UnknownVariables():
print("unknown variable: %s=%s" % (key, value))

vars.Save(filename, env)
Save the currently set variables into a script file named by
filename that can be used on the next invocation to automatically
load the current settings. This method combined with the Variables
method can be used to support caching of variables between runs.

env = Environment()
vars = Variables(['variables.cache', 'custom.py'])
vars.Add(...)
vars.Update(env)
vars.Save('variables.cache', env)

vars.GenerateHelpText(env, [sort])
Generate help text documenting the customizable construction
variables, suitable for passing in to the Help function. env is
the construction environment that will be used to get the actual
values of the customizable variables. If the (optional) value of
sort is callable, it is used as a comparison function to determine
how to sort the added variables. This function must accept two
arguments, compare them, and return a negative integer if the first
is less-than the second, zero for equality, or a positive integer
for greater-than. Optionally a Boolean value of True for sort will
cause a standard alphabetical sort to be performed.

Help(vars.GenerateHelpText(env))

def cmp(a, b):
return (a > b) - (a < b)

Help(vars.GenerateHelpText(env, sort=cmp))

vars.FormatVariableHelpText(env, opt, help, default, actual)
Returns a formatted string containing the printable help text for
one option. It is normally not called directly, but is called by
the GenerateHelpText method to create the returned help text. It
may be overridden with your own function that takes the arguments
specified above and returns a string of help text formatted to your
liking. Note that GenerateHelpText will not put any blank lines or
extra characters in between the entries, so you must add those
characters to the returned string if you want the entries
separated.

def my_format(env, opt, help, default, actual):
fmt = "\n%s: default=%s actual=%s (%s)\n"
return fmt % (opt, default, actual, help)
vars.FormatVariableHelpText = my_format

To make it more convenient to work with customizable Variables, scons
provides a number of functions that make it easy to set up various
types of Variables. Each of these return a tuple ready to be passed to
the Add or AddVariables method:

BoolVariable(key, help, default)
Returns a tuple of arguments to set up a Boolean option. The option
will use the specified name key, have a default value of default,
and help will form the descriptive part of the help text. The
option will interpret the values y, yes, t, true, 1, on and all as
true, and the values n, no, f, false, 0, off and none as false.

EnumVariable(key, help, default, allowed_values, [map, ignorecase])
Returns a tuple of arguments to set up an option whose value may be
one of a specified list of legal enumerated values. The option will
use the specified name key, have a default value of default, and
help will form the descriptive part of the help text. The option
will only support those values in the allowed_values list. The
optional map argument is a dictionary that can be used to convert
input values into specific legal values in the allowed_values list.
If the value of ignore_case is 0 (the default), then the values are
case-sensitive. If the value of ignore_case is 1, then values will
be matched case-insensitively. If the value of ignore_case is 2,
then values will be matched case-insensitively, and all input
values will be converted to lower case.

ListVariable(key, help, default, names, [map])
Returns a tuple of arguments to set up an option whose value may be
one or more of a specified list of legal enumerated values. The
option will use the specified name key, have a default value of
default, and help will form the descriptive part of the help text.
The option will only accept the values "all", "none", or the values
in the names list. More than one value may be specified, separated
by commas. The default may be a string of comma-separated default
values, or a list of the default values. The optional map argument
is a dictionary that can be used to convert input values into
specific legal values in the names list. (Note that the additional
values accepted through the use of a map are not reflected in the
generated help message).

PackageVariable(key, help, default)
Returns a tuple of arguments to set up an option whose value is a
path name of a package that may be enabled, disabled or given an
explicit path name. The option will use the specified name key,
have a default value of default, and help will form the descriptive
part of the help text. The option will support the values yes,
true, on, enable or search, in which case the specified default
will be used, or the option may be set to an arbitrary string
(typically the path name to a package that is being enabled). The
option will also support the values no, false, off or disable to
disable use of the specified option.

PathVariable(key, help, default, [validator])
Returns a tuple of arguments to set up an option whose value is
expected to be a path name. The option will use the specified name
key, have a default value of default, and help will form the
descriptive part of the help text. An additional validator may be
specified that will be called to verify that the specified path is
acceptable. SCons supplies the following ready-made validators:

PathVariable.PathExists
Verify that the specified path exists (this the default
behavior if no validator is supplied).

PathVariable.PathIsFile
Verify that the specified path exists and is a regular file.

PathVariable.PathIsDir
Verify that the specified path exists and is a directory.

PathVariable.PathIsDirCreate
Verify that the specified path exists and is a directory; if it
does not exist, create the directory.

PathVariable.PathAccept
Accept the specific path name argument without validation,
suitable for when you want your users to be able to specify a
directory path that will be created as part of the build
process, for example.

You may supply your own validator function, which must accept three
arguments (key, the name of the variable to be set; val, the
specified value being checked; and env, the construction
environment) and should raise an exception if the specified value
is not acceptable.

These functions make it convenient to create a number of variables with
consistent behavior in a single call to the AddVariables method:

vars.AddVariables(
BoolVariable(
"warnings",
help="compilation with -Wall and similar",
default=1,
),
EnumVariable(
"debug",
help="debug output and symbols",
default="no",
allowed_values=("yes", "no", "full"),
map={},
ignorecase=0, # case sensitive
),
ListVariable(
"shared",
help="libraries to build as shared libraries",
default="all",
names=list_of_libs,
),
PackageVariable(
"x11",
help="use X11 installed here (yes = search some places)",
default="yes",
),
PathVariable(
"qtdir",
help="where the root of Qt is installed",
default=qtdir),
PathVariable(
"foopath",
help="where the foo library is installed",
default=foopath,
validator=PathVariable.PathIsDir,
),
)

File and Directory Nodes
The File and Dir functions/methods return File and Directory Nodes,
respectively. Such nodes are Python objects with several user-visible
attributes and methods that are often useful to access in SConscript
files:

n.path
The build path of the given file or directory. This path is
relative to the top-level directory (where the SConstruct file is
found). The build path is the same as the source path if
variant_dir is not being used.

n.abspath
The absolute build path of the given file or directory.

n.relpath
The build path of the given file or directory relative to the root
SConstruct file's directory.

n.srcnode()
The srcnode method returns another File or Directory Node
representing the source path of the given File or Directory Node.

For example:

# Get the current build dir's path, relative to top.
Dir('.').path
# Current dir's absolute path
Dir('.').abspath
# Current dir's path relative to the root SConstruct file's directory
Dir('.').relpath
# Next line is always '.', because it is the top dir's path relative to itself.
Dir('#.').path
File('foo.c').srcnode().path # source path of the given source file.

# Builders also return File objects:
foo = env.Program('foo.c')
print("foo will be built in", foo.path)

File and Directory Node objects have methods to create File and
Directory Nodes relative to the original Node.

If the object is a Directory Node, these methods will place the the new
Node within the directory the Node represents:

d.Dir(name)
Returns a directory Node for a subdirectory of d named name.

d.File(name)
Returns a file Node for a file within d named name.

d.Entry(name)
Returns an unresolved Node within d named name.

If the object is a File Node, these methods will place the the new Node
in the same directory as the one the Node represents:

f.Dir(name)
Returns a directory named name within the parent directory of f.

f.File(name)
Returns a file named name within the parent directory of f.

f.Entry(name)
Returns an unresolved Node named name within the parent directory
of f.

For example:

# Get a Node for a file within a directory
incl = Dir('include')
f = incl.File('header.h')

# Get a Node for a subdirectory within a directory
dist = Dir('project-3.2.1')
src = dist.Dir('src')

# Get a Node for a file in the same directory
cfile = File('sample.c')
hfile = cfile.File('sample.h')

# Combined example
docs = Dir('docs')
html = docs.Dir('html')
index = html.File('index.html')
css = index.File('app.css')

EXTENDING SCONS
Builder Objects
scons can be extended to build different types of targets by adding new
Builder objects to a construction environment. In general, you should
only need to add a new Builder object when you want to build a new type
of file or other external target. For output file types scons already
knows about, you can usually modify the behavior of premade Builders
such as Program, Object or Library by changing the construction
variables they use ($CC, $LINK, etc.). In this manner you can, for
example, change the compiler to use, which is simpler and less
error-prone than writing a new builder. The documentation for each
Builder lists which construction variables it uses.

Builder objects are created using the Builder factory function. Once
created, a builder is added to an environment by entering it in the
$BUILDERS dictionary in that environment (some of the examples in this
section illustrate that).

The Builder function accepts the following keyword arguments:

action
The command used to build the target from the source. action may
be a string representing a template command line to execute, a list
of strings representing the command to execute with its arguments
(suitable for enclosing white space in an argument), a dictionary
mapping source file name suffixes to any combination of command
line strings (if the builder should accept multiple source file
extensions), a Python function, an Action object (see the section
called "Action Objects") or a list of any of the above.

An action function must accept three arguments: source, target and
env. source is a list of source nodes; target is a list of target
nodes; env is the construction environment to use for context.

The action and generator arguments must not both be used for the
same Builder.

prefix
The prefix to prepend to the target file name. prefix may be a
string, a function (or other callable) that takes two arguments (a
construction environment and a list of sources) and returns a
prefix string, or a dictionary specifying a mapping from a specific
source suffix (of the first source specified) to a corresponding
target prefix string. For the dictionary form, both the source
suffix (key) and target prefix (value) specifications may use
environment variable substitution, and the target prefix may also
be a callable object. The default target prefix may be indicated by
a dictionary entry with a key of None.

b = Builder("build_it < $SOURCE > $TARGET",
prefix="file-")

def gen_prefix(env, sources):
return "file-" + env['PLATFORM'] + '-'

b = Builder("build_it < $SOURCE > $TARGET",
prefix=gen_prefix)

b = Builder("build_it < $SOURCE > $TARGET",
suffix={None: "file-", "$SRC_SFX_A": gen_prefix})

suffix
The suffix to append to the target file name. Specified in the same
manner as for prefix above. If the suffix is a string, then scons
prepends a '.' to the suffix if it's not already there. The string
returned by the callable object or obtained from the dictionary is
untouched and you need to manually prepend a '.' if one is
required.

b = Builder("build_it < $SOURCE > $TARGET"
suffix="-file")

def gen_suffix(env, sources):
return "." + env['PLATFORM'] + "-file"

b = Builder("build_it < $SOURCE > $TARGET",
suffix=gen_suffix)

b = Builder("build_it < $SOURCE > $TARGET",
suffix={None: ".sfx1", "$SRC_SFX_A": gen_suffix})

ensure_suffix
If set to a true value, ensures that targets will end in suffix.
Thus, the suffix will also be added to any target strings that have
a suffix that is not already suffix. The default behavior (also
indicated by a false value) is to leave unchanged any target string
that looks like it already has a suffix.

b1 = Builder("build_it < $SOURCE > $TARGET"
suffix = ".out")
b2 = Builder("build_it < $SOURCE > $TARGET"
suffix = ".out",
ensure_suffix=True)
env = Environment()
env['BUILDERS']['B1'] = b1
env['BUILDERS']['B2'] = b2

# Builds "foo.txt" because ensure_suffix is not set.
env.B1('foo.txt', 'foo.in')

# Builds "bar.txt.out" because ensure_suffix is set.
env.B2('bar.txt', 'bar.in')

src_suffix
The expected source file name suffix. src_suffix may be a string
or a list of strings.

target_scanner
A Scanner object that will be invoked to find implicit dependencies
for this target file. This keyword argument should be used for
Scanner objects that find implicit dependencies based only on the
target file and the construction environment, not for implicit
dependencies based on source files. See the section called "Scanner
Objects" for information about creating Scanner objects.

source_scanner
A Scanner object that will be invoked to find implicit dependencies
in any source files used to build this target file. This is where
you would specify a scanner to find things like #include lines in
source files. The pre-built DirScanner Scanner object may be used
to indicate that this Builder should scan directory trees for
on-disk changes to files that scons does not know about from other
Builder or function calls. See the section called "Scanner Objects"
for information about creating your own Scanner objects.

target_factory
A factory function that the Builder will use to turn any targets
specified as strings into SCons Nodes. By default, SCons assumes
that all targets are files. Other useful target_factory values
include Dir, for when a Builder creates a directory target, and
Entry, for when a Builder can create either a file or directory
target.

Example:

MakeDirectoryBuilder = Builder(action=my_mkdir, target_factory=Dir)
env = Environment()
env.Append(BUILDERS={'MakeDirectory': MakeDirectoryBuilder})
env.MakeDirectory('new_directory', [])

Note that the call to this MakeDirectory Builder needs to specify
an empty source list to make the string represent the builder's
target; without that, it would assume the argument is the source,
and would try to deduce the target name from it, which in the
absence of an automatically-added prefix or suffix would lead to a
matching target and source name and a circular dependency.

source_factory
A factory function that the Builder will use to turn any sources
specified as strings into SCons Nodes. By default, SCons assumes
that all source are files. Other useful source_factory values
include Dir, for when a Builder uses a directory as a source, and
Entry, for when a Builder can use files or directories (or both) as
sources.

Example:

CollectBuilder = Builder(action=my_mkdir, source_factory=Entry)
env = Environment()
env.Append(BUILDERS={'Collect': CollectBuilder})
env.Collect('archive', ['directory_name', 'file_name'])

emitter
A function or list of functions to manipulate the target and source
lists before dependencies are established and the target(s) are
actually built. emitter can also be a string containing a
construction variable to expand to an emitter function or list of
functions, or a dictionary mapping source file suffixes to emitter
functions. (Only the suffix of the first source file is used to
select the actual emitter function from an emitter dictionary.)

A function passed as emitter must accept three arguments: source,
target and env. source is a list of source nodes, target is a list
of target nodes, env is the construction environment to use for
context.

An emitter must return a tuple containing two lists, the list of
targets to be built by this builder, and the list of sources for
this builder.

Example:

def e(target, source, env):
return (target + ['foo.foo'], source + ['foo.src'])

# Simple association of an emitter function with a Builder.
b = Builder("my_build < $TARGET > $SOURCE",
emitter = e)

def e2(target, source, env):
return (target + ['bar.foo'], source + ['bar.src'])

# Simple association of a list of emitter functions with a Builder.
b = Builder("my_build < $TARGET > $SOURCE",
emitter = [e, e2])

# Calling an emitter function through a construction variable.
env = Environment(MY_EMITTER=e)
b = Builder("my_build < $TARGET > $SOURCE",
emitter='$MY_EMITTER')

# Calling a list of emitter functions through a construction variable.
env = Environment(EMITTER_LIST=[e, e2])
b = Builder("my_build < $TARGET > $SOURCE",
emitter='$EMITTER_LIST')

# Associating multiple emitters with different file
# suffixes using a dictionary.
def e_suf1(target, source, env):
return (target + ['another_target_file'], source)
def e_suf2(target, source, env):
return (target, source + ['another_source_file'])
b = Builder("my_build < $TARGET > $SOURCE",
emitter={'.suf1' : e_suf1,
'.suf2' : e_suf2})

multi
Specifies whether this builder is allowed to be called multiple
times for the same target file(s). The default is False, which
means the builder can not be called multiple times for the same
target file(s). Calling a builder multiple times for the same
target simply adds additional source files to the target; it is not
allowed to change the environment associated with the target,
specify additional environment overrides, or associate a different
builder with the target.

env
A construction environment that can be used to fetch source code
using this Builder. (Note that this environment is not used for
normal builds of normal target files, which use the environment
that was used to call the Builder for the target file.)

generator
A function that returns a list of actions that will be executed to
build the target(s) from the source(s). The returned action(s) may
be an Action object, or anything that can be converted into an
Action object (see the next section).

A function passed as generator must accept four arguments: source,
target, env and for_signature. source is a list of source nodes,
target is a list of target nodes, env is the construction
environment to use for context, for_signature is a Boolean value
that specifies whether the generator is being called for generating
a build signature (as opposed to actually executing the command).

Example:

def g(source, target, env, for_signature):
return [["gcc", "-c", "-o"] + target + source]

b = Builder(generator=g)

The generator and action arguments must not both be used for the
same Builder.

src_builder
Specifies a builder to use when a source file name suffix does not
match any of the suffixes of the builder. Using this argument
produces a multi-stage builder.

single_source
Specifies that this builder expects exactly one source file per
call. Giving more than one source file without target files results
in implicitly calling the builder multiple times (once for each
source given). Giving multiple source files together with target
files results in a UserError exception.

source_ext_match
When the specified action argument is a dictionary, the default
behavior when a builder is passed multiple source files is to make
sure that the extensions of all the source files match. If it is
legal for this builder to be called with a list of source files
with different extensions, this check can be suppressed by setting
source_ext_match to False or some other non-true value. In this
case, scons will use the suffix of the first specified source file
to select the appropriate action from the action dictionary.

In the following example, the setting of source_ext_match prevents
scons from exiting with an error due to the mismatched suffixes of
foo.in and foo.extra.

b = Builder(action={'.in' : 'build $SOURCES > $TARGET'},
source_ext_match=False)

env = Environment(BUILDERS={'MyBuild':b})
env.MyBuild('foo.out', ['foo.in', 'foo.extra'])

b = Builder(action="build < $SOURCE > $TARGET")
env = Environment(BUILDERS={'MyBuild' : b})
env.MyBuild('foo.out', 'foo.in', my_arg='xyzzy')

chdir
A directory from which scons will execute the action(s) specified
for this Builder. If the chdir argument is a string or a directory
Node, scons will change to the specified directory. If the chdir is
not a string or Node and is non-zero, then scons will change to the
target file's directory.

Note that scons will not automatically modify its expansion of
construction variables like $TARGET and $SOURCE when using the
chdir keyword argument--that is, the expanded file names will still
be relative to the top-level directory containing the SConstruct
file, and consequently incorrect relative to the chdir directory.
Builders created using chdir keyword argument, will need to use
construction variable expansions like ${TARGET.file} and
${SOURCE.file} to use just the filename portion of the targets and
source.

b = Builder(action="build < ${SOURCE.file} > ${TARGET.file}",
chdir=1)
env = Environment(BUILDERS={'MyBuild' : b})
env.MyBuild('sub/dir/foo.out', 'sub/dir/foo.in')

Warning
Python only keeps one current directory location even if there
are multiple threads. This means that use of the chdir argument
will not work with the SCons -j option, because individual
worker threads spawned by SCons interfere with each other when
they start changing directory.

Any additional keyword arguments supplied when a Builder object is
created (that is, when the Builder function is called) will be set in
the executing construction environment when the Builder object is
called. The canonical example here would be to set a construction
variable to the repository of a source code system.

Any additional keyword arguments supplied when a Builder object is
called will only be associated with the target created by that
particular Builder call (and any other files built as a result of the
call).

These extra keyword arguments are passed to the following functions:
command generator functions, function Actions, and emitter functions.

Action Objects
The Builder factory function will turn its action keyword argument into
an appropriate internal Action object, as will the Command function.
You can also explicitly create Action objects for passing to Builder,
or other functions that take actions as arguments, by calling the
Action factory function. This may more efficient when multiple Builder
objects need to do the same thing rather than letting each of those
Builder objects create a separate Action object. It also allows more
flexible configuration of an Action object. For example, to control the
message printed when the action is taken you need to create the action
object using Action.

The Action factory function returns an appropriate object for the
action represented by the type of the action argument (the first
positional parmeter):

o If action is already an Action object, the object is simply
returned.

o If action is a string, a command-line Action is returned. If such a
string begins with @, the command line is not printed. If the
string begins with hyphen (-), the exit status from the specified
command is ignored, allowing execution to continue even if the
command reports failure:

Action('$CC -c -o $TARGET $SOURCES')

# Doesn't print the line being executed.
Action('@build $TARGET $SOURCES')

# Ignores return value
Action('-build $TARGET $SOURCES')

o If action is a list, then a list of Action objects is returned. An
Action object is created as necessary for each element in the list.
If an element within the list is itself a list, the embedded list
is taken as the command and arguments to be executed via the
command line. This allows white space to be enclosed in an argument
rather than taken as a separator by defining a command in a list
within a list:

Action([['cc', '-c', '-DWHITE SPACE', '-o', '$TARGET', '$SOURCES']])

o If action is a callable object, a Function Action is returned. The
callable must accept three keyword arguments: target, source and
env. target is a Node object representing the target file, source
is a Node object representing the source file and env is the
construction environment used for building the target file.

The target and source arguments may be lists of Node objects if
there is more than one target file or source file. The actual
target and source file name(s) may be retrieved from their Node
objects via the built-in Python str function:

target_file_name = str(target)
source_file_names = [str(x) for x in source]

The function should return 0 or None to indicate a successful build
of the target file(s). The function may raise an exception or
return a non-zero exit status to indicate an unsuccessful build.

def build_it(target=None, source=None, env=None):
# build the target from the source
return 0

a = Action(build_it)

o If action is not one of the above types, no action object is
generated and Action returns None.

The environment method form env.Action will expand construction
variables in any argument strings, including action, at the time it is
called, using the construction variables in the construction
environment through which it was called. The global function form
Action delays variable expansion until the Action object is actually
used.

The optional second argument to Action is used to control the output
which is printed when the Action is actually performed. If this
parameter is omitted, or if the value is an empty string, a default
output depending on the type of the action is used. For example, a
command-line action will print the executed command. The following
argument types are accepted:

o If output is a string, substitution is performed on the string
before it is printed. The string typically contains variables,
notably $TARGET(S) and $SOURCE(S), or consists of just a single
variable, which is optionally defined somewhere else. SCons itself
heavily uses the latter variant.

o If output is a function, the function will be called to obtain a
string describing the action being executed. The function must
accept three keyword arguments: target, source and env, with the
same interpretation as for a callable action argument above.

o If outputis None, output is suppressed entirely.

Instead of using a positional argument, the cmdstr keyword argument may
be used to specify the output string, or the strfunction keyword
argument may be used to specify a function to return the output string.
cmdstr=None suppresses output entirely.

Examples:

def build_it(target, source, env):
# build the target from the source
return 0

def string_it(target, source, env):
return "building '%s' from '%s'" % (target[0], source[0])

# Use a positional argument.
f = Action(build_it, string_it)
s = Action(build_it, "building '$TARGET' from '$SOURCE'")

# Alternatively, use a keyword argument.
f = Action(build_it, strfunction=string_it)
s = Action(build_it, cmdstr="building '$TARGET' from '$SOURCE'")

# You can provide a configurable variable.
l = Action(build_it, '$STRINGIT')

Any additional positional arguments, if present, may either be
construction variables or lists of construction variables whose values
will be included in the signature of the Action when deciding whether a
target should be rebuilt because the action changed. Such variables may
also be specified using the varlist keyword parameter; both positional
and keyword forms may be present, and will be combined. This is
necessary whenever you want a target to be rebuilt when a specific
construction variable changes. This is not often needed for a string
action, as the expanded variables will normally be part of the command
line, but may be needed if a Python function action uses the value of a
construction variable when generating the command line.

def build_it(target, source, env):
# build the target from the 'XXX' construction variable
with open(target[0], 'w') as f:
f.write(env['XXX'])
return 0

# Use positional arguments.
a = Action(build_it, '$STRINGIT', ['XXX'])

# Alternatively, use a keyword argument.
a = Action(build_it, varlist=['XXX'])

The Action factory function can be passed the following optional
keyword arguments to modify the Action object's behavior:

chdir
If chdir is true (the default is False), SCons will change
directories before executing the action. If the value of chdir is a
string or a directory Node, SCons will change to the specified
directory. Otherwise, if chdir evaluates true, SCons will change to
the target file's directory.

Note that SCons will not automatically modify its expansion of
construction variables like $TARGET and $SOURCE when using the
chdir parameter - that is, the expanded file names will still be
relative to the top-level directory containing the SConstruct file,
and consequently incorrect relative to the chdir directory.
Builders created using chdir keyword argument, will need to use
construction variable expansions like ${TARGET.file} and
${SOURCE.file} to use just the filename portion of the targets and
source. Example:

a = Action("build < ${SOURCE.file} > ${TARGET.file}", chdir=True)

exitstatfunc
If provided, must be a callable which accepts a single parameter,
the exit status (or return value) from the specified action, and
which returns an arbitrary or modified value. This can be used, for
example, to specify that an Action object's return value should be
ignored under special conditions and SCons should, therefore,
consider that the action always succeeds. Example:

def always_succeed(s):
# Always return 0, which indicates success.
return 0

a = Action("build < ${SOURCE.file} > ${TARGET.file}",
exitstatfunc=always_succeed)

batch_key
If provided, indicates that the Action can create multiple target
files by processing multiple independent source files
simultaneously. (The canonical example is "batch compilation" of
multiple object files by passing multiple source files to a single
invocation of a compiler such as Microsoft's Visual C / C++
compiler.) If the batch_key argument evaluates True and is not a
callable object, the configured Action object will cause scons to
collect all targets built with the Action object and configured
with the same construction environment into single invocations of
the Action object's command line or function. Command lines will
typically want to use the $CHANGED_SOURCES construction variable
(and possibly $CHANGED_TARGETS as well) to only pass to the command
line those sources that have actually changed since their targets
were built. Example:

a = Action('build $CHANGED_SOURCES', batch_key=True)

The batch_key argument may also be a callable function that returns
a key that will be used to identify different "batches" of target
files to be collected for batch building. A batch_key function must
accept four parameters: action, env, target and source. The first
parameter, action, is the active action object. The second
parameter, env, is the construction environment configured for the
target. The target and source parameters are the lists of targets
and sources for the configured action.

The returned key should typically be a tuple of values derived from
the arguments, using any appropriate logic to decide how multiple
invocations should be batched. For example, a batch_key function
may decide to return the value of a specific construction variable
from env which will cause scons to batch-build targets with
matching values of that construction variable, or perhaps return
the Python id() of the entire construction environment, in which
case scons will batch-build all targets configured with the same
construction environment. Returning None indicates that the
particular target should not be part of any batched build, but
instead will be built by a separate invocation of action's command
or function. Example:

def batch_key(action, env, target, source):
tdir = target[0].dir
if tdir.name == 'special':
# Don't batch-build any target
# in the special/ subdirectory.
return None
return (id(action), id(env), tdir)
a = Action('build $CHANGED_SOURCES', batch_key=batch_key)

Miscellaneous Action Functions
SCons supplies Action functions that arrange for various common file
and directory manipulations to be performed. These are similar in
concept to "tasks" in the Ant build tool, although the implementation
is slightly different. These functions do not actually perform the
specified action at the time the function is called, but rather are
factory functions which return an Action object that can be executed at
the appropriate time.

There are two natural ways that these Action Functions are intended to
be used.

First, if you need to perform the action at the time the SConscript
file is being read, you can use the Execute global function:

Execute(Touch('file'))

Second, you can use these functions to supply Actions in a list for use
by the env.Command method. This can allow you to perform more
complicated sequences of file manipulation without relying on
platform-specific external commands:

env = Environment(TMPBUILD='/tmp/builddir')
env.Command(
target='foo.out',
source='foo.in',
action=[
Mkdir('$TMPBUILD'),
Copy('$TMPBUILD', '${SOURCE.dir}'),
"cd $TMPBUILD && make",
Delete('$TMPBUILD'),
],
)

Chmod(dest, mode)
Returns an Action object that changes the permissions on the
specified dest file or directory to the specified mode which can be
octal or string, similar to the bash command. Examples:

Execute(Chmod('file', 0o755))

env.Command('foo.out', 'foo.in',
[Copy('$TARGET', '$SOURCE'),
Chmod('$TARGET', 0o755)])

Execute(Chmod('file', "ugo+w"))

env.Command('foo.out', 'foo.in',
[Copy('$TARGET', '$SOURCE'),
Chmod('$TARGET', "ugo+w")])

The behavior of Chmod is limited on Windows, see the notes in the
Python documentation for os.chmod, which is the underlying
function.

Copy(dest, src)
Returns an Action object that will copy the src source file or
directory to the dest destination file or directory. Examples:

Execute(Copy('foo.output', 'foo.input'))

env.Command('bar.out', 'bar.in', Copy('$TARGET', '$SOURCE'))

Delete(entry, [must_exist])
Returns an Action that deletes the specified entry, which may be a
file or a directory tree. If a directory is specified, the entire
directory tree will be removed. If the must_exist flag is set to a
true value, then a Python error will be raised if the specified
entry does not exist; the default is false, that is, the Action
will silently do nothing if the entry does not exist. Examples:

Execute(Delete('/tmp/buildroot'))

env.Command(
'foo.out',
'foo.in',
action=[
Delete('${TARGET.dir}'),
MyBuildAction,
],
)

Execute(Delete('file_that_must_exist', must_exist=True))

Mkdir(name)
Returns an Action that creates the directory name and all needed
intermediate directories. name may also be a list of directories
to create. Examples:

Execute(Mkdir('/tmp/outputdir'))

env.Command(
'foo.out',
'foo.in',
action=[
Mkdir('/tmp/builddir'),
Copy('/tmp/builddir/foo.in', '$SOURCE'),
"cd /tmp/builddir && make",
Copy('$TARGET', '/tmp/builddir/foo.out'),
],
)

Move(dest, src)
Returns an Action that moves the specified src file or directory to
the specified dest file or directory. Examples:

Execute(Move('file.destination', 'file.source'))

env.Command(
'output_file',
'input_file',
action=[MyBuildAction, Move('$TARGET', 'file_created_by_MyBuildAction')],
)

Touch(file)
Returns an Action that updates the modification time on the
specified file. Examples:

Execute(Touch('file_to_be_touched'))

env.Command('marker', 'input_file', action=[MyBuildAction, Touch('$TARGET')])

Variable Substitution
Before executing a command, scons performs variable substitution on the
string that makes up the action part of the builder. Variables to be
interpolated are indicated in the string with a leading $, to
distinguish them from plain text which is not to be substituted. The
name may be surrounded by curly braces (${}) to separate the name from
surrounding characters if necessary. Curly braces are required when you
use Python list subscripting/slicing notation on a variable to select
one or more items from a list, or access a variable's special
attributes, or use Python expression substitution.

Besides regular construction variables, scons provides the following
special variables for use in expanding commands:

$CHANGED_SOURCES
The file names of all sources of the build command that have
changed since the target was last built.

$CHANGED_TARGETS
The file names of all targets that would be built from sources that
have changed since the target was last built.

$SOURCE
The file name of the source of the build command, or the file name
of the first source if multiple sources are being built.

$SOURCES
The file names of the sources of the build command.

$TARGET
The file name of the target being built, or the file name of the
first target if multiple targets are being built.

$TARGETS
The file names of all targets being built.

$UNCHANGED_SOURCES
The file names of all sources of the build command that have not
changed since the target was last built.

$UNCHANGED_TARGETS
The file names of all targets that would be built from sources that
have not changed since the target was last built.

These names are reserved and may not be assigned to or used as
construction variables.

For example, the following builder call:

env = Environment(CC='cc')
env.Command(
target=['foo'],
source=['foo.c', 'bar.c'],
action='@echo $CC -c -o $TARGET $SOURCES'
)

would produce the following output:

cc -c -o foo foo.c bar.c

In the previous example, a string ${SOURCES[1]} would expand to: bar.c.

A variable name may have the following modifiers appended within the
enclosing curly braces to access properties of the interpolated string.
These are known as special attributes.
base -
The base path of the file name,
including the directory path
but excluding any suffix.

dir - The name of the directory in which the file exists.
file - The file name, minus any directory portion.
filebase - Like file but minus its suffix.
suffix - Just the file suffix.
abspath - The absolute path name of the file.
relpath - The path name of the file relative to the root SConstruct
file's directory.
posix -
The path with directories separated by forward slashes
(/).
Sometimes necessary on Windows systems
when a path references a file on other (POSIX) systems.

windows -
The path with directories separated by backslashes
(\\).
Sometimes necessary on POSIX-style systems
when a path references a file on other (Windows) systems.
win32 is a (deprecated) synonym for
windows.

srcpath -
The directory and file name to the source file linked to this
file through
VariantDir().
If this file isn't linked,
it just returns the directory and filename unchanged.

srcdir -
The directory containing the source file linked to this file
through
VariantDir().
If this file isn't linked,
it just returns the directory part of the filename.

rsrcpath -
The directory and file name to the source file linked to this
file through
VariantDir().
If the file does not exist locally but exists in a Repository,
the path in the Repository is returned.
If this file isn't linked, it just returns the
directory and filename unchanged.

rsrcdir -
The Repository directory containing the source file linked to
this file through
VariantDir().
If this file isn't linked,
it just returns the directory part of the filename.

For example, the specified target will expand as follows for the
corresponding modifiers:

$TARGET => sub/dir/file.x
${TARGET.base} => sub/dir/file
${TARGET.dir} => sub/dir
${TARGET.file} => file.x
${TARGET.filebase} => file
${TARGET.suffix} => .x
${TARGET.abspath} => /top/dir/sub/dir/file.x
${TARGET.relpath} => sub/dir/file.x

$TARGET => ../dir2/file.x
${TARGET.abspath} => /top/dir2/file.x
${TARGET.relpath} => ../dir2/file.x

SConscript('src/SConscript', variant_dir='sub/dir')
$SOURCE => sub/dir/file.x
${SOURCE.srcpath} => src/file.x
${SOURCE.srcdir} => src

Repository('/usr/repository')
$SOURCE => sub/dir/file.x
${SOURCE.rsrcpath} => /usr/repository/src/file.x
${SOURCE.rsrcdir} => /usr/repository/src

Some modifiers can be combined, like ${TARGET.srcpath.base),
${TARGET.file.suffix}, etc.

The curly brace notation may also be used to enclose a Python
expression to be evaluated. See the section called "Python Code
Substitution" below for a description.

A variable name may also be a Python function associated with a
construction variable in the environment. The function should accept
four arguments:
target - a list of target nodes
source - a list of source nodes
env - the construction environment
for_signature -
a Boolean value that specifies
whether the function is being called
for generating a build signature.

SCons will insert whatever the called function returns into the
expanded string:

def foo(target, source, env, for_signature):
return "bar"

# Will expand $BAR to "bar baz"
env=Environment(FOO=foo, BAR="$FOO baz")

As a reminder, this evaluation happens when $BAR is actually used in a
builder action. The value of env['BAR'] will be exactly as it was set:
"$FOO baz".

You can use this feature to pass arguments to a Python function by
creating a callable class that stores one or more arguments in an
object, and then uses them when the __call__() method is called. Note
that in this case, the entire variable expansion must be enclosed by
curly braces so that the arguments will be associated with the
instantiation of the class:

class foo:
def __init__(self, arg):
self.arg = arg

def __call__(self, target, source, env, for_signature):
return self.arg + " bar"

# Will expand $BAR to "my argument bar baz"
env=Environment(FOO=foo, BAR="${FOO('my argument')} baz")

The special pseudo-variables $( and $) may be used to surround parts of
a command line that may change without causing a rebuild--that is,
which are not included in the signature of target files built with this
command. All text between $( and $) will be removed from the command
line before it is added to file signatures, and the $( and $) will be
removed before the command is executed. For example, the command line:

echo Last build occurred $( $TODAY $). > $TARGET

would execute the command:

echo Last build occurred $TODAY. > $TARGET

but the command signature added to any target files would be:

echo Last build occurred . > $TARGET

Python Code Substitution
If a substitutable expression using the notation ${something} does not
appear to match one of the other substitution patterns, it is evaluated
as a Python expression. This uses Python's eval function, with the
globals parameter set to the current environment's set of construction
variables, and the result substituted in. So in the following case:

env.Command(
'foo.out', 'foo.in', "echo ${COND==1 and 'FOO' or 'BAR'} > $TARGET"
)

the command executed will be either

echo FOO > foo.out

echo BAR > foo.out

according to the current value of env['COND'] when the command is
executed. The evaluation takes place when the target is being built,
not when the SConscript is being read. So if env['COND'] is changed
later in the SConscript, the final value will be used.

Here's a more complete example. Note that all of COND, FOO, and BAR are
construction variables, and their values are substituted into the final
command. FOO is a list, so its elements are interpolated separated by
spaces.

env=Environment()
env['COND'] = 1
env['FOO'] = ['foo1', 'foo2']
env['BAR'] = 'barbar'
env.Command(
'foo.out', 'foo.in', "echo ${COND==1 and FOO or BAR} > $TARGET"
)

will execute:

echo foo1 foo2 > foo.out

In point of fact, Python expression evaluation is how the special
attributes are substituted: they are simply attributes of the Python
objects that represent $TARGET, $SOURCES, etc., which SCons passes to
eval which returns the value.

SCons uses the following rules when converting construction variables
into command lines:

string
When the value is a string it is interpreted as a space delimited
list of command line arguments.

list
When the value is a list it is interpreted as a list of command
line arguments. Each element of the list is converted to a string.

other
Anything that is not a list or string is converted to a string and
interpreted as a single command line argument.

newline
Newline characters (\n) delimit lines. The newline parsing is done
after all other parsing, so it is not possible for arguments (e.g.
file names) to contain embedded newline characters.

Note
Use of the Python eval function is considered to have security
implications, since, depending on input sources, arbitrary
unchecked strings of code can be executed by the Python
interpreter. Although SCons makes use of it in a somewhat
restricted context, you should be aware of this issue when using
the ${python-expression-for-subst} form.

Scanner Objects
You can use the Scanner function to define objects to scan new file
types for implicit dependencies. The Scanner function accepts the
following arguments:

function
This can be either:

o a Python function that will process the Node (file) and return
a list of File Nodes representing the implicit dependencies
(file names) found in the contents.

o a dictionary that maps keys (typically the file suffix, but see
below for more discussion) to other Scanners that should be
called.

If the argument is a Python function, the function must accept
three required arguments and an optional fourth:
node -
The internal SCons node representing the file.
Use str(node)
to fetch the name of the file, and
node.get_contents()
to fetch the contents of the file as bytes or
node.get_text_contents()
to fetch the contents as text.
Note that the file is
not
guaranteed to exist before the scanner is called,
so the scanner function should check that
if there's any chance that the scanned file
might not exist
(for example, if it's built from other files).

env - The construction environment for the scan.
path -
A tuple (or list)
of directories that can be searched
for files.
This will usually be the tuple returned by the
path_function
argument (see below).

arg -
The argument supplied when the scanner was created, if any
(default None.

name
The name of the Scanner. This is mainly used to identify the
Scanner internally. The default value is "NONE".

argument
An optional argument that, if specified, will be passed to the
scanner function (described above) and the path function (specified
below).

skeys
An optional list that can be used to determine which scanner should
be used for a given Node. In the usual case of scanning for file
names, this argument will be a list of suffixes for the different
file types that this Scanner knows how to scan. If the argument is
a string, then it will be expanded into a list by the current
environment.

path_function
A Python function that takes four or five arguments: a construction
environment, a Node for the directory containing the SConscript
file in which the first target was defined, a list of target nodes,
a list of source nodes, and an optional argument supplied when the
scanner was created. The path_function returns a tuple of
directories that can be searched for files to be returned by this
Scanner object. (Note that the FindPathDirs function can be used to
return a ready-made path_function for a given construction variable
name, instead of having to write your own function from scratch.)

node_class
The class of Node that should be returned by this Scanner object.
Any strings or other objects returned by the scanner function that
are not of this class will be run through the function supplied by
the node_factory argument.

node_factory
A Python function that will take a string or other object and turn
it into the appropriate class of Node to be returned by this
Scanner object.

scan_check
An optional Python function that takes two arguments, a Node (file)
and a construction environment, and returns whether the Node
should, in fact, be scanned for dependencies. This check can be
used to eliminate unnecessary calls to the scanner function when,
for example, the underlying file represented by a Node does not yet
exist.

recursive
An optional flag that specifies whether this scanner should be
re-invoked on the dependency files returned by the scanner. When
this flag is not set, the Node subsystem will only invoke the
scanner on the file being scanned, and not (for example) also on
the files specified by the #include lines in the file being
scanned. recursive may be a callable function, in which case it
will be called with a list of Nodes found and should return a list
of Nodes that should be scanned recursively; this can be used to
select a specific subset of Nodes for additional scanning.

Note that scons has a global SourceFileScanner object that is used by
the Object, SharedObject and StaticObject builders to decide which
scanner should be used for different file extensions. You can use the
SourceFileScanner.add_scanner() method to add your own Scanner object
to the SCons infrastructure that builds target programs or libraries
from a list of source files of different types:

def xyz_scan(node, env, path):
contents = node.get_text_contents()
# Scan the contents and return the included files.

XYZScanner = Scanner(xyz_scan)

SourceFileScanner.add_scanner('.xyz', XYZScanner)

env.Program('my_prog', ['file1.c', 'file2.f', 'file3.xyz'])

SYSTEM-SPECIFIC BEHAVIOR
scons and its configuration files are very portable, due largely to its
implementation in Python. There are, however, a few portability issues
waiting to trap the unwary.

.C file suffix
scons handles the upper-case .C file suffix differently, depending on
the capabilities of the underlying system. On a case-sensitive system
such as Linux or UNIX, scons treats a file with a .C suffix as a C++
source file. On a case-insensitive system such as Windows, scons treats
a file with a .C suffix as a C source file.

Fortran file suffixes
scons handles upper-case Fortran file suffixes differently depending on
the capabilities of the underlying system. On a case-sensitive system
such as Linux or UNIX, scons treats a file with a .F as a Fortran
source file that is to be first run through the standard C
preprocessor, while the lower-case version is not. This matches the
convention of gfortran, which may also be followed by other Fortran
compilers. This also applies to other naming variants, .FOR, .FTN,
.F90, .F95, .F03 and .F08; files suffixed with .FPP and .fpp are both
run through the preprocessor, as indicated by the pp part of the name.
On a case-insensitive system such as Windows, scons treats a file with
a .F suffix as a Fortran source file that should not be run through the
C preprocessor.

Run through the C preprocessor here means that a different set of
construction variables will be applied in constructed commands, for
example $FORTRANPPCOM and $FORTRANPPCOMSTR instead of $FORTRANCOM and
$FORTRANCOMSTR. See the Fortran-related construction variables for more
details.

Windows: Cygwin Tools and Cygwin Python vs. Windows Pythons
Cygwin supplies a set of tools and utilities that let users work on a
Windows system using a more POSIX-like environment. The Cygwin tools,
including Cygwin Python, do this, in part, by sharing an ability to
interpret UNIX-like path names. For example, the Cygwin tools will
internally translate a Cygwin path name like /cygdrive/c/mydir to an
equivalent Windows pathname of C:/mydir (equivalent to C:\mydir).

Versions of Python that are built for native Windows execution, such as
the python.org and ActiveState versions, do not have the Cygwin path
name semantics. This means that using a native Windows version of
Python to build compiled programs using Cygwin tools (such as gcc,
bison and flex) may yield unpredictable results. "Mixing and matching"
in this way can be made to work, but it requires careful attention to
the use of path names in your SConscript files.

In practice, users can sidestep the issue by adopting the following
rules: When using gcc, use the Cygwin-supplied Python interpreter to
run scons; when using Microsoft Visual C/C++ (or some other Windows
compiler) use the python.org or Microsoft Store or ActiveState version
of Python to run scons.

Windows: scons.bat file
On Windows systems, scons is executed via a wrapper scons.bat file.
This has (at least) two ramifications:

First, Windows command-line users that want to use variable assignment
on the command line may have to put double quotes around the
assignments:

scons "FOO=BAR" "BAZ=BLEH"

Second, the Cygwin shell does not recognize this file as being the same
as an scons command issued at the command-line prompt. You can work
around this either by executing scons.bat from the Cygwin command line,
or by creating a wrapper shell script named scons.

MinGW
The MinGW bin directory must be in your PATH environment variable or
the ['ENV']['PATH'] construction variable for scons to detect and use
the MinGW tools. When running under the native Windows Python
interpreter, scons will prefer the MinGW tools over the Cygwin tools,
if they are both installed, regardless of the order of the bin
directories in the PATH variable. If you have both MSVC and MinGW
installed and you want to use MinGW instead of MSVC, then you must
explicitly tell scons to use MinGW by passing tools=['mingw'] to the
Environment function, because scons will prefer the MSVC tools over the
MinGW tools.

ENVIRONMENT
In general, scons is not controlled by environment variables set in the
shell used to invoke it, leaving it up to the SConscript file author to
import those if desired. However the following variables are imported
by scons itself if set:

SCONS_LIB_DIR
Specifies the directory that contains the scons Python module
directory. Normally scons can deduce this, but in some
circumstances, such as working with a source release, it may be
necessary to specify (for example,
/home/aroach/scons-src-0.01/src/engine).

SCONSFLAGS
A string containing options that will be used by scons in addition
to those passed on the command line. Can be used to reduce frequent
retyping of common options. The contents of SCONSFLAGS are
considered before any passed command line options, so the command
line can be used to override SCONSFLAGS options if necessary.

SCONS_CACHE_MSVC_CONFIG
(Windows only). If set, save the shell environment variables
generated when setting up the Microsoft Visual C++ compiler (and/or
Build Tools) to a cache file, to give these settings, which are
relatively expensive to generate, persistence across scons
invocations. Use of this option is primarily intended to aid
performance in tightly controlled Continuous Integration setups.

If set to a True-like value ("1", "true" or "True") will cache to a
file named .scons_msvc_cache in the user's home directory. If set
to a pathname, will use that pathname for the cache.

Note: use this cache with caution as it might be somewhat fragile:
while each major toolset version (e.g. Visual Studio 2017 vs 2019)
and architecture pair will get separate cache entries, if toolset
updates cause a change to settings within a given release series,
scons will not detect the change and will reuse old settings.
Remove the cache file in case of problems with this. scons will
ignore failures reading or writing the file and will silently
revert to non-cached behavior in such cases.

Available since scons 3.1 (experimental).

ATTRIBUTES
See attributes(7) for descriptions of the following attributes:

SEE ALSO
The SCons User Guide at
https://scons.org/doc/production/HTML/scons-user.html

The SCons Design Document (old)

The SCons Cookbook at
https://scons-cookbook.readthedocs.io
for examples of how to solve various problems with SCons.

SCons source code
on GitHub[5]

The SCons API Reference
https://scons.org/doc/production/HTML/scons-api/index.html
(for internal details)

AUTHORS
Originally: Steven Knight knight@baldmt.com and Anthony Roach
aroach@electriceyeball.com.

Since 2010: The SCons Development Team scons-dev@scons.org.

AUTHOR
The SCons Development Team

NOTES
1. LLVM specification
https://clang.llvm.org/docs/JSONCompilationDatabase.html

2. ninja package
https://pypi.org/project/ninja/

3. If no_progress is set via SetOption in an SConscript file (but not
if set in a site_init.py file) there will still be an initial
status message about reading SConscript files since SCons has to
start reading them before it can see the SetOption.

4. http://www.opensource.org/licenses/alphabetical
http://www.opensource.org/licenses/alphabetical

5. on GitHub
https://github.com/SCons/scons

Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.

This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
https://sourceforge.net/projects/scons/files/scons/4.2.0/scons-4.2.0.tar.gz/download.

Further information about this software can be found on the open source
community website at http://www.scons.org/.

SCons 4.2.0 Version 4.2.0
<pubdate>Released Sat, 31 Jul 2021 18:12:46 -0700</pubdate>
SCONS(1)

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scons (1)

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