To access the procedures in the Tcl library, an application should
source the file init.tcl in the library, for example with
the Tcl command
- 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.
For example, to run the umask shell builtin on Linux, you would do:
exec {*}[auto_execok umask]
To run the DIR shell builtin on Windows, you would do:
exec {*}[auto_execok dir]
To discover if there is a frobnicate binary on the user's PATH,
you would do:
set mayFrob [expr {[llength [auto_execok frobnicate]] > 0}]
- 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.
It is not normally necessary to call this command directly.
- 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 evaluate 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
successfully 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.
It is not normally necessary to call this command directly; the
default unknown handler will do so.
- 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
child 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 definitions 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 procedure 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 namespace, 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 absolute (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 basenameversion
(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 environment 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 parallel build tree.
- parray arrayName ?pattern?
-
Prints on standard output the names and values of all the elements in the
array arrayName, or just the names that match pattern (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.
The result of this command is the empty string.
For example, to print the contents of the tcl_platform array, do:
parray tcl_platform
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Copyright © 1994-1996 Sun Microsystems, Inc.