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'\" Copyright (c) 1991-1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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'\" RCS: @(#) $Id: library.n,v 1.16.14.8 2010/01/14 17:10:08 dgp Exp $
.so man.macros
.TH library n "8.0" Tcl "Tcl Built-In Commands"
.BS
.SH 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
.SH SYNOPSIS
.nf

The location of the Tcl library is returned by the \fBinfo library\fR
command.
In addition to the Tcl library, each application will normally have
its own library of support procedures as well;  the location of this
library is normally given by the value of the \fB$\fIapp\fB_library\fR
global variable, where \fIapp\fR is the name of the application.
For example, the location of the Tk library is kept in the variable
\fBtk_library\fR.
.PP
To access the procedures in the Tcl library, an application should
source the file \fBinit.tcl\fR in the library, for example with
the Tcl command
.PP
.CS
\fBsource [file join [info library] init.tcl]\fR

does nothing.  The pattern matching is performed according to the
matching rules of \fBnamespace import\fR.
.TP
\fBauto_load \fIcmd\fR
This command attempts to load the definition for a Tcl command named
\fIcmd\fR.  To do this, it searches an \fIauto-load path\fR, which is
a list of one or more directories.  The auto-load path is given by the
global variable \fBauto_path\fR if it exists.  If there is no
\fBauto_path\fR 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 \fBtclIndex\fR that describes one or more
commands defined in that directory and a script to evaluate to load
each of the commands.  The \fBtclIndex\fR file should be generated
with the \fBauto_mkindex\fR command.  If \fIcmd\fR is found in an
index file, then the appropriate script is evaluated to create the

bin or bin/\fIarch\fR directory;
relative to the executable file in the current build tree;
relative to the executable file in a parallel build tree.
.TP
\fBparray \fIarrayName\fR
Prints on standard output the names and values of all the elements
in the array \fIarrayName\fR.
\fIArrayName\fR must be an array accessible to the caller of \fBparray\fR.
It may be either local or global.
.TP
\fBtcl_endOfWord \fIstr start\fR
Returns the index of the first end-of-word location that occurs after
a starting index \fIstart\fR in the string \fIstr\fR.  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

\fIstart\fR in the string \fIstr\fR.  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.
.SH "VARIABLES"
.PP
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.
.SS "AUTOLOADING AND PACKAGE MANAGEMENT VARIABLES"
.TP
\fBauto_execs\fR
Used by \fBauto_execok\fR to record information about whether
particular commands exist as executable files.
.TP
\fBauto_index\fR
Used by \fBauto_load\fR to save the index information read from

If set to any value, then \fBunknown\fR will not attempt to auto-load
any commands.
.TP
\fBauto_path\fR
If set, then it must contain a valid Tcl list giving directories to
search during auto-load operations.
This variable is initialized during startup to contain, in order:
the directories listed in the \fBTCLLIBPATH\fR environment variable,
the directory named by the \fBtcl_library\fR variable,
the parent directory of \fBtcl_library\fR,
the directories listed in the \fBtcl_pkgPath\fR variable.
.TP
\fBenv(TCL_LIBRARY)\fR
If set, then it specifies the location of the directory containing
library scripts (the value of this variable will be
assigned to the \fBtcl_library\fR variable and therefore returned by
the command \fBinfo library\fR).  If this variable is not set then
a default value is used.
.TP
\fBenv(TCLLIBPATH)\fR
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
.QW /
as the path separator, regardless of platform.
This variable is only used when initializing the \fBauto_path\fR variable.
.SS "WORD BOUNDARY DETERMINATION VARIABLES"
These variables are only used in the \fBtcl_endOfWord\fR,
\fBtcl_startOfNextWord\fR, \fBtcl_startOfPreviousWord\fR,
\fBtcl_wordBreakAfter\fR, and \fBtcl_wordBreakBefore\fR commands.
.TP
\fBtcl_nonwordchars\fR
This variable contains a regular expression that is used by routines
like \fBtcl_endOfWord\fR to identify whether a character is part of a
word or not.  If the pattern matches a character, the character is
considered to be a non-word character.  On Windows platforms, spaces,
tabs, and newlines are considered non-word characters.  Under Unix,