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Updated: Thursday, June 13, 2019
 
 

auto_execok (1t)

Name

auto_execok - auto_execok, auto_import, auto_load, auto_mkindex, auto_qualify, auto_reset, tcl_findLibrary, parray, tcl_endOfWord, tcl_startOfNextWord, tcl_startOfPreviousWord, tcl_wordBreakAfter, standard library of Tcl procedures

Synopsis

auto_execok cmd
auto_import pattern
auto_load cmd
auto_mkindex dir pattern pattern ...
auto_qualify command namespace
auto_reset
tcl_findLibrary basename version patch initScript enVarName varName
parray arrayName ?pattern?
tcl_endOfWord str start
tcl_startOfNextWord str start
tcl_startOfPreviousWord str start
tcl_wordBreakAfter str start
tcl_wordBreakBefore str start

Description

library(1t)                  Tcl Built-In Commands                 library(1t)



______________________________________________________________________________

NAME
       auto_execok,   auto_import,   auto_load,   auto_mkindex,  auto_qualify,
       auto_reset,       tcl_findLibrary,        parray,        tcl_endOfWord,
       tcl_startOfNextWord,    tcl_startOfPreviousWord,    tcl_wordBreakAfter,
       tcl_wordBreakBefore - standard library of Tcl procedures

SYNOPSIS
       auto_execok cmd
       auto_import pattern
       auto_load cmd
       auto_mkindex dir pattern pattern ...
       auto_qualify command namespace
       auto_reset
       tcl_findLibrary basename version patch initScript enVarName varName
       parray arrayName ?pattern?
       tcl_endOfWord str start
       tcl_startOfNextWord str start
       tcl_startOfPreviousWord str start
       tcl_wordBreakAfter str start
       tcl_wordBreakBefore str start
______________________________________________________________________________

INTRODUCTION
       Tcl includes a library of Tcl procedures for commonly-needed functions.
       The procedures defined in the Tcl library are generic ones suitable for
       use by many different applications.  The location of the Tcl library is
       returned  by the info library command.  In addition to the Tcl library,
       each application will normally have its own library of  support  proce-
       dures  as  well;  the location of this library is normally given by the
       value of the $app_library global variable, where app is the name of the
       application.   For  example,  the location of the Tk library is kept in
       the variable tk_library.

       To access the procedures in the  Tcl  library,  an  application  should
       source  the file init.tcl in the library, for example with the Tcl com-
       mand

              source [file join [info library] init.tcl]

       If the library procedure Tcl_Init  is  invoked  from  an  application's
       Tcl_AppInit   procedure,  this  happens  automatically.   The  code  in
       init.tcl will define the unknown procedure and arrange  for  the  other
       procedures to be loaded on-demand using the auto-load mechanism defined
       below.

COMMAND PROCEDURES
       The following procedures are provided in the Tcl library:

       auto_execok cmd
              Determines whether there is an executable file or shell  builtin
              by  the  name  cmd.  If so, it returns a list of arguments to be
              passed to exec to execute the executable file or  shell  builtin
              named by cmd.  If not, it returns an empty string.  This command
              examines the directories in the current search  path  (given  by
              the  PATH  environment variable) in its search for an executable
              file named cmd.  On Windows platforms, the  search  is  expanded
              with  the  same directories and file extensions as used by exec.
              Auto_execok remembers information about previous searches in  an
              array  named  auto_execs;  this avoids the path search in future
              calls for the same cmd.  The command auto_reset may be  used  to
              force auto_execok to forget its cached information.

       auto_import pattern
              Auto_import  is  invoked  during  namespace import to see if the
              imported commands specified by pattern reside in  an  autoloaded
              library.   If  so,  the commands are loaded so that they will be
              available to the interpreter for creating the import links.   If
              the commands do not reside in an autoloaded library, auto_import
              does nothing.  The pattern matching is  performed  according  to
              the matching rules of namespace import.

       auto_load cmd
              This  command  attempts to load the definition for a Tcl command
              named cmd.  To do this, it searches an auto-load path, which  is
              a  list of one or more directories.  The auto-load path is given
              by the global variable auto_path if it exists.  If there  is  no
              auto_path  variable, then the TCLLIBPATH environment variable is
              used, if it exists.  Otherwise the auto-load  path  consists  of
              just  the  Tcl  library directory.  Within each directory in the
              auto-load path there must be a file tclIndex that describes  one
              or more commands defined in that directory and a script to eval-
              uate to load each of the commands.  The tclIndex file should  be
              generated  with the auto_mkindex command.  If cmd is found in an
              index file, then the appropriate script is evaluated  to  create
              the  command.   The  auto_load command returns 1 if cmd was suc-
              cessfully created.  The command returns 0 if there was no  index
              entry for cmd or if the script did not actually define cmd (e.g.
              because index information is out of date).  If an  error  occurs
              while  processing  the  script,  then  that  error  is returned.
              Auto_load only reads the index information once and saves it  in
              the  array  auto_index;  future calls to auto_load check for cmd
              in the array rather than re-reading the index files.  The cached
              index  information  may  be deleted with the command auto_reset.
              This will force the next auto_load command to reload  the  index
              database from disk.

       auto_mkindex dir pattern pattern ...
              Generates  an  index suitable for use by auto_load.  The command
              searches dir for all files whose names match any of the  pattern
              arguments (matching is done with the glob command), generates an
              index of all the Tcl  command  procedures  defined  in  all  the
              matching files, and stores the index information in a file named
              tclIndex in dir. If no pattern is given a pattern of *.tcl  will
              be assumed.  For example, the command

                     auto_mkindex foo *.tcl

              will  read all the .tcl files in subdirectory foo and generate a
              new index file foo/tclIndex.

              Auto_mkindex parses the Tcl scripts  by  sourcing  them  into  a
              slave interpreter and monitoring the proc and namespace commands
              that  are  executed.   Extensions  can  use  the  (undocumented)
              auto_mkindex_parser  package to register other commands that can
              contribute to the auto_load index. You will have to read through
              auto.tcl to see how this works.

              Auto_mkindex_old  (which  has  the  same syntax as auto_mkindex)
              parses the Tcl scripts in a relatively unsophisticated way:   if
              any  line  contains the word "proc" as its first characters then
              it is assumed to be a procedure definition and the next word  of
              the  line  is  taken as the procedure's name.  Procedure defini-
              tions that do not appear in  this  way  (e.g. they  have  spaces
              before  the  proc) will not be indexed.  If your script contains
              "dangerous" code, such as global initialization code  or  proce-
              dure  names  with  special characters like $, *, [ or ], you are
              safer using auto_mkindex_old.

       auto_reset
              Destroys  all  the  information  cached   by   auto_execok   and
              auto_load.   This information will be re-read from disk the next
              time it is  needed.   Auto_reset  also  deletes  any  procedures
              listed in the auto-load index, so that fresh copies of them will
              be loaded the next time that they are used.

       auto_qualify command namespace
              Computes a list of fully qualified names for command.  This list
              mirrors  the path a standard Tcl interpreter follows for command
              lookups:  first it looks for the command in the  current  names-
              pace, and then in the global namespace.  Accordingly, if command
              is relative and namespace is not ::, the list returned  has  two
              elements:   command scoped by namespace, as if it were a command
              in the namespace namespace; and command as if it were a  command
              in  the global namespace.  Otherwise, if either command is abso-
              lute (it begins with ::), or namespace is ::, the list  contains
              only command as if it were a command in the global namespace.

              Auto_qualify is used by the auto-loading facilities in Tcl, both
              for producing auto-loading indexes such as pkgIndex.tcl, and for
              performing the actual auto-loading of functions at runtime.

       tcl_findLibrary basename version patch initScript enVarName varName
              This is a standard search procedure for use by extensions during
              their initialization.  They call  this  procedure  to  look  for
              their  script library in several standard directories.  The last
              component of the name of the library directory is normally base-
              nameversion (e.g., tk8.0), but it might be "library" when in the
              build hierarchies.  The initScript file will be sourced into the
              interpreter  once it is found.  The directory in which this file
              is found is stored into the global variable  varName.   If  this
              variable  is already defined (e.g., by C code during application
              initialization) then no searching is done.  Otherwise the search
              looks  in these directories: the directory named by the environ-
              ment variable enVarName; relative to the Tcl library  directory;
              relative to the executable file in the standard installation bin
              or bin/arch directory; relative to the executable  file  in  the
              current  build tree; relative to the executable file in a paral-
              lel build tree.

       parray arrayName ?pattern?
              Prints on standard output the names and values of all  the  ele-
              ments  in the array arrayName, or just the names that match pat-
              tern (using the matching rules of string match) and their values
              if  pattern  is given.  ArrayName must be an array accessible to
              the caller of parray.  It may be either local or global.

       tcl_endOfWord str start
              Returns the index of the first end-of-word location that  occurs
              after  a starting index start in the string str.  An end-of-word
              location is defined to be the first non-word character following
              the  first  word character after the starting point.  Returns -1
              if there are no more end-of-word locations  after  the  starting
              point.   See  the  description of tcl_wordchars and tcl_nonword-
              chars below for more details on how Tcl determines which charac-
              ters are word characters.

       tcl_startOfNextWord str start
              Returns  the  index  of  the  first  start-of-word location that
              occurs after a starting index start in the string str.  A start-
              of-word  location is defined to be the first word character fol-
              lowing a non-word character.  Returns -1 if there  are  no  more
              start-of-word locations after the starting point.

       tcl_startOfPreviousWord str start
              Returns  the  index  of  the  first  start-of-word location that
              occurs before a starting index start in the string str.  Returns
              -1  if  there  are  no  more  start-of-word locations before the
              starting point.

       tcl_wordBreakAfter str start
              Returns the index of the first word boundary after the  starting
              index  start in the string str.  Returns -1 if there are no more
              boundaries after the starting point in the  given  string.   The
              index  returned  refers to the second character of the pair that
              comprises a boundary.

       tcl_wordBreakBefore str start
              Returns the index of the first word boundary before the starting
              index  start in the string str.  Returns -1 if there are no more
              boundaries before the starting point in the given  string.   The
              index  returned  refers to the second character of the pair that
              comprises a boundary.

VARIABLES
       The following global variables are defined or used by the procedures in
       the  Tcl  library.  They  fall into two broad classes, handling unknown
       commands and packages, and determining what are words.

   AUTOLOADING AND PACKAGE MANAGEMENT VARIABLES
       auto_execs
              Used by auto_execok to record information about whether particu-
              lar commands exist as executable files.

       auto_index
              Used by auto_load to save the index information read from disk.

       auto_noexec
              If  set to any value, then unknown will not attempt to auto-exec
              any commands.

       auto_noload
              If set to any value, then unknown will not attempt to  auto-load
              any commands.

       auto_path
              If set, then it must contain a valid Tcl list giving directories
              to search during auto-load  operations  (including  for  package
              index  files  when  using  the default package unknown handler).
              This variable is  initialized  during  startup  to  contain,  in
              order:  the  directories  listed  in  the TCLLIBPATH environment
              variable, the directory named by the  tcl_library  global  vari-
              able,  the  parent  directory  of  tcl_library,  the directories
              listed in the tcl_pkgPath  variable.   Additional  locations  to
              look  for  files and package indices should normally be added to
              this variable using lappend.

       env(TCL_LIBRARY)
              If set, then it specifies the location of the directory contain-
              ing library scripts (the value of this variable will be assigned
              to the tcl_library variable and therefore returned by  the  com-
              mand  info library).  If this variable is not set then a default
              value is used.

       env(TCLLIBPATH)
              If set, then it must contain a valid Tcl list giving directories
              to  search  during  auto-load  operations.   Directories must be
              specified in Tcl  format,  using  "/"  as  the  path  separator,
              regardless  of  platform.   This variable is only used when ini-
              tializing the auto_path variable.

   WORD BOUNDARY DETERMINATION VARIABLES
       These   variables    are    only    used    in    the    tcl_endOfWord,
       tcl_startOfNextWord,  tcl_startOfPreviousWord,  tcl_wordBreakAfter, and
       tcl_wordBreakBefore commands.

       tcl_nonwordchars
              This variable contains a regular expression that is used by rou-
              tines like tcl_endOfWord to identify whether a character is part
              of a word or not.  If the pattern matches a character, the char-
              acter  is  considered  to  be  a non-word character.  On Windows
              platforms, spaces, tabs, and newlines  are  considered  non-word
              characters.   Under  Unix,  everything  but numbers, letters and
              underscores are considered non-word characters.

       tcl_wordchars
              This variable contains a regular expression that is used by rou-
              tines like tcl_endOfWord to identify whether a character is part
              of a word or not.  If the pattern matches a character, the char-
              acter  is  considered  to be a word character.  On Windows plat-
              forms, words are comprised of any character that is not a space,
              tab,  or  newline.   Under Unix, words are comprised of numbers,
              letters or underscores.


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | runtime/tcl-8    |
       +---------------+------------------+
       |Stability      | Uncommitted      |
       +---------------+------------------+
SEE ALSO
       env(n), info(n), re_syntax(n)

KEYWORDS
       auto-exec, auto-load, library, unknown, word, whitespace



NOTES
       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source was downloaded from  http://prdownloads.sourceforge.net/tcl/tcl-
       core8.6.7-src.tar.gz

       Further information about this software can be found on the open source
       community website at https://www.tcl.tk/.



Tcl                                   8.0                          library(1t)