c99 - compile standard C programs
c99 [-c] [-Dname[=tokens]] [-E] [-g] [-Idirectory]
[-Ldirectory] [-Ooptlevel] [-ooutfile] [-s] [-Uname]
This release of the c99 utility is compliant with the Standard for Information Technology - Portable Operating System Interface (POSIX(R)) Shell and Utilities, Issue 6 (Volume 1: A to J) Approved 12 September 2001.
The c99 utility is an interface to the standard C compilation system; it will accept source code conforming to the ISO C standard. The system conceptually consists of a compiler and link editor. The files referenced by operands will be compiled and linked to produce an executable file.
If the -c option is specified, for all pathname operands of the form file.c,the files:
$(basename pathname .c).o
will be created as the result of successful compilation.
If there are no options that prevent link editing (such as -c or -E), and all operands compile and link without error, the resulting executable file will be written according to the -o outfile option (if present) or to the file a.out.
The file permissions for the executable file that is created are set to
S_IRWXO | S_IRWXG | S_IRWXU
and the bits specified by the umask of the process are cleared.
The following affect the options for the c99 utility:
The -l library operands have the format of options, but their position within a list of operands affects the order in which libraries are searched.
The order of specifying the -I and -L options is significant.
Portable applications must specify each option separately; that is, grouping option letters (for example, -cO) need not be recognized by all implementations.
The following options are supported:
Suppress the link-edit phase of the compilation, and do not remove any object files that are produced.
Define name as if by a C-language #define directive. If no =value is given, a value of 1 will be used. The -D option has lower precedence than the -U option; that is, if name is used in both a -U and a -D option, name will be undefined regardless of the order of the options. c99 supports at least 2048 bytes of -D definitions and 256 names.
The following predefined names are valid in all modes:
__sparc (SPARC) __i386 (x86) __unix __sun __BUILTIN_VA_ARG_INCR __SUNPRO_C=0x500 __SVR4
The following names are not predefined:
unix sparc (SPARC) i386 (x86) sun
Copy C-language source files to standard output, expanding all preprocessor directives; no compilation will be performed. An error will occur if any operand is not a text file.
Produce symbolic information in the object or executable files.
Change the algorithm for searching for headers whose names are not absolute pathnames to look in the directory named by the directory path name before looking in the usual places. Thus, headers whose names are enclosed in double-quotes ("") will be searched for first in the directory of the file with the #include line, then in directories named in -I options, and last in the usual places. For headers whose names are enclosed in angle brackets (<>), the header will be searched for only in directories named in -I options and then in the usual places. Directories named in -I options will be searched in the order specified.
Change the algorithm of searching for the libraries named in the -l objects to look in the directory named by the directory path name before looking in the usual places. Directories named in -L options will be searched in the order specified.
Specify the level of code optimization. If the optlevel option-argument is the digit 0, all special code optimizations are disabled. See the cc(1) manpage for a description of the optimization levels.
Use the pathname outfile, instead of the default a.out, for the executable file produced. This option cannot be used with -c or -E.
Produce object or executable files, or both, from which symbolic and other information not required for proper execution using the exec family has been removed (stripped). If both -g and -s options are present, -s overrides -g.
Remove any initial definition of name.
Multiple instances of the -D, -I, -U, and -L options can be specified.
An operand is either in the form of a path name or the form -l library. At least one operand of the path name form must be specified. The following operands are supported:
A C-language source file to be compiled and optionally linked. The operand must be of this form if the -c option is used.
A library of object files typically produced by the ar(1) utility, and passed directly to the link editor.
An object file produced by c99 -c and passed directly to the link editor.
(The letter ell.) Search the library named liblibrary.a.
A library will be searched when its name is encountered, so the placement of a -l operand is significant. Several standard libraries can be specified in this manner. See Standard Libraries in NOTES below.
Since the c99 utility usually creates files in the current directory during the compilation process, it is typically necessary to run the c99 utility in a directory in which a file can be created.
c99 creates .o files when -c is not specified and more than one source file is given.
Some historical implementations have permitted -L options to be interspersed with -l operands on the command line. For an application to compile consistently on systems that do not behave like this, it is necessary for a portable application to supply all -L options before any of the -l options.
There is the possible implication that if a user supplies versions of the standard library functions (before they would be encountered by an implicit -l c or explicit -l m), that those versions would be used in place of the standard versions. There are various reasons this might not be true (functions defined as macros, manipulations for clean name space, and so forth), so the existence of files named in the same manner as the standard libraries within the -L directories is explicitly stated to produce unspecified behavior.
Setting the environment variable TMPDIR overrides the default temporary directory.
If more than one file operand ending in .c is given, for each such file:
"%s:\n", <file>
may be written. These messages, if written, will precede the processing of each input file; they will not be written to the standard output if they are written to the standard error, as described in STDERR.
If the -E option is specified, the standard output will be a text file that represents the results of the preprocessing stage of the language; it may contain extra information appropriate for subsequent compilation passes.
Used only for diagnostic messages. If more than one file operand ending in .c (or possibly other unspecified suffixes) is given, for each such file:
"%s:\n", <file>
may be written to allow identification of the diagnostic and warning messages with the appropriate input file. These messages, if written, will precede the processing of each input file; they will not be written to the standard error if they are written to the standard output, as described in STDOUT.
See environ (5) for descriptions of the following environment variables that affect the execution of c99: LANG, LC_ALL, LC_TYPE, LC_MESSAGES, and NLSPATH.
Provide a path name that will override the default directory for temporary files, if any.
The following exit values are returned:
Successful compilation or link edit.
An error occurred.
When c99 encounters a compilation error that causes an object file not to be created, it will write a diagnostic to standard error and continue to compile other source code operands, but it will not perform the link phase and will return a non-zero exit status. If the link edit is unsuccessful, a diagnostic message will be written to standard error and c99 will exit with a non-zero status. A portable application must rely on the exit status of c99, rather than on the existence or mode of the executable file.
The following are examples of usage:
Compiles foo.c and creates the executable file foo.
Compiles foo.c and creates the object file foo.o.
Compiles foo.c and creates the executable file a.out.
Compiles foo.c, links it with bar.o, and creates the executable file a.out. Also creates and leaves foo.o.
The following examples clarify the use and interactions of -L options and -l operands: Consider the case in which module a.c calls function f in library libQ.a, and module b.c calls function g in library libp.a. Assume that both libraries reside in /a/b/c. The command line to compile and link in the desired way is:
c89 -L /a/b/c main.o a.c -l Q b.c -l p
In this case the -l Q operand need only precede the first -l p operand, since both libQ.a and libp.a reside in the same directory. Multiple -L operands can be used when library name collisions occur. Building on the previous example, suppose that the user wants to use a new libp.a, in /a/a/a, but still wants f from /a/b/c/libQ.a:
c89 -L /a/a/a -L /a/b/c main.o a.c -l Q b.c -l p
In this example, the linker searches the -L options in the order specified, and finds /a/a/a/libp.a before /a/b/c/libp.a when resolving references for b.c. The order of the -l operands is still important, however.
ar(1), cc(1B), nm(1), strip(1), umask(1), environ(5)
The c99 utility recognizes the following -l operands for standard libraries:
This library contains all library functions except for those functions listed as residing in <math.h>. This operand is not required to be present to cause a search of this library.
This library contains all functions referenced in math.h. An implementation may search this library in the absence of this operand.
This library contains all functions required by the C-language output of lex that are not made available through the -l c operand.
This operand makes visible all functions referenced in <pthread.h> and pthread_atfork() referenced in <unistd.h>. An implementation may search this library in the absence of this operand.
This operand makes visible all functions referenced in <aio.h>, <mqueue.h>, <sched.h>, and <time.h>. An implementation may search this library in the absence of this operand.
This library contains all functions required by the C-language output of yacc that are not made available through the -l c operand.
In the absence of options that inhibit invocation of the link editor, such as -c or -E, the c99 utility will cause the equivalent of a -l c operand to be passed to the link editor as the last -l operand, causing it to be searched after all other object files and libraries are loaded.
The C compiler and link editor support the significance of external symbols up to a length of at least 31 bytes.
The compiler and link editor support a minimum of 511 external symbols per source or object file, and a minimum of 4095 external symbols in total. A diagnostic message will be written to the standard output if the limit is exceeded.