'\" '\" Copyright (c) 1991-1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" SCCS: @(#) library.n 1.20 96/03/25 20:18:29 '\" The definitions below are for supplemental macros used in Tcl/Tk '\" manual entries. '\" '\" .AP type name in/out ?indent? '\" Start paragraph describing an argument to a library procedure. '\" type is type of argument (int, etc.), in/out is either "in", "out", '\" or "in/out" to describe whether procedure reads or modifies arg, '\" and indent is equivalent to second arg of .IP (shouldn't ever be '\" needed; use .AS below instead) '\" '\" .AS ?type? ?name? '\" Give maximum sizes of arguments for setting tab stops. Type and '\" name are examples of largest possible arguments that will be passed '\" to .AP later. If args are omitted, default tab stops are used. '\" '\" .BS '\" Start box enclosure. From here until next .BE, everything will be '\" enclosed in one large box. '\" '\" .BE '\" End of box enclosure. '\" '\" .CS '\" Begin code excerpt. '\" '\" .CE '\" End code excerpt. '\" '\" .VS ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. If an argument is present, then a line break is '\" forced before starting the sidebar. '\" '\" .VE '\" End of vertical sidebar. '\" '\" .DS '\" Begin an indented unfilled display. '\" '\" .DE '\" End of indented unfilled display. '\" '\" .SO '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four columns separated '\" by tabs. '\" '\" .SE '\" End of list of standard options for a Tk widget. '\" '\" .OP cmdName dbName dbClass '\" Start of description of a specific option. cmdName gives the '\" option's name as specified in the class command, dbName gives '\" the option's name in the option database, and dbClass gives '\" the option's class in the option database. '\" '\" .UL arg1 arg2 '\" Print arg1 underlined, then print arg2 normally. '\" '\" SCCS: @(#) man.macros 1.8 96/02/15 20:02:24 '\" '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b '\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ie !"\\$3"" \{\ .ta \\n()Au \\n()Bu \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. '\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out '\" # BS - start boxed text '\" # ^y = starting y location '\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. '\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. '\" # VS - start vertical sidebar '\" # ^Y = starting y location '\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$1"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. '\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. '\" # Special macro to handle page bottom: finish off current '\" # box/sidebar if in box/sidebar mode, then invoked standard '\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. '\" # DS - begin display .de DS .RS .nf .sp .. '\" # DE - end display .de DE .fi .RE .sp .. '\" # SO - start of list of standard options .de SO .SH "STANDARD OPTIONS" .LP .nf .ta 4c 8c 12c .ft B .. '\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\fBoptions\\fR manual entry for details on the standard options. .. '\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. '\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. '\" # CE - end code excerpt .de CE .fi .RE .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH library n "" Tcl "Tcl Built-In Commands" .BS .SH NAME library \- standard library of Tcl procedures .SH SYNOPSIS .nf \fBauto_execok \fIcmd\fR \fBauto_load \fIcmd\fR \fBauto_mkindex \fIdir pattern pattern ...\fR \fBauto_reset\fR \fBparray \fIarrayName\fR .BE .SH INTRODUCTION .PP 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 \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$\fIapp\fB_library\fR global variable, where \fIapp\fR is the name of the application. For example, the location of the Tk library is kept in the variable \fB$tk_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 .CS \fBsource [info library]/init.tcl\fR .CE If the library procedure \fBTcl_Init\fR is invoked from an application's \fBTcl_AppInit\fR procedure, this happens automatically. The code in \fBinit.tcl\fR will define the \fBunknown\fR procedure and arrange for the other procedures to be loaded on-demand using the auto-load mechanism defined below. .SH "COMMAND PROCEDURES" .PP The following procedures are provided in the Tcl library: .TP \fBauto_execok \fIcmd\fR Determines whether there is an executable file by the name \fIcmd\fR. This command examines the directories in the current search path (given by the PATH environment variable) to see if there is an executable file named \fIcmd\fR in any of those directories. If so, it returns 1; if not it returns 0. \fBAuto_exec\fR remembers information about previous searches in an array named \fBauto_execs\fR; this avoids the path search in future calls for the same \fIcmd\fR. The command \fBauto_reset\fR may be used to force \fBauto_execok\fR to forget its cached information. .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 \fB$auto_path\fR if it exists. If there is no \fB$auto_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 .VS 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 command. .VE The \fBauto_load\fR command returns 1 if \fIcmd\fR was successfully created. The command returns 0 if there was no index entry for \fIcmd\fR or if the script didn't actually define \fIcmd\fR (e.g. because index information is out of date). If an error occurs while processing the script, then that error is returned. \fBAuto_load\fR only reads the index information once and saves it in the array \fBauto_index\fR; future calls to \fBauto_load\fR check for \fIcmd\fR in the array rather than re-reading the index files. The cached index information may be deleted with the command \fBauto_reset\fR. This will force the next \fBauto_load\fR command to reload the index database from disk. .TP \fBauto_mkindex \fIdir pattern pattern ...\fR .VS Generates an index suitable for use by \fBauto_load\fR. The command searches \fIdir\fR for all files whose names match any of the \fIpattern\fR arguments .VE (matching is done with the \fBglob\fR 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 \fBtclIndex\fR in \fIdir\fR. If no pattern is given a pattern of \fB*.tcl\fR will be assumed. For example, the command .RS .CS \fBauto_mkindex foo *.tcl\fR .CE .LP will read all the \fB.tcl\fR files in subdirectory \fBfoo\fR and generate a new index file \fBfoo/tclIndex\fR. .PP \fBAuto_mkindex\fR parses the Tcl scripts in a relatively unsophisticated way: if any line contains the word \fBproc\fR 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 don't appear in this way (e.g. they have spaces before the \fBproc\fR) will not be indexed. .RE .TP \fBauto_reset\fR Destroys all the information cached by \fBauto_execok\fR and \fBauto_load\fR. This information will be re-read from disk the next time it is needed. \fBAuto_reset\fR also deletes any procedures listed in the auto-load index, so that fresh copies of them will be loaded the next time that they're used. .TP \fBparray \fIarrayName\fR Prints on standard output the names and values of all the elements in the array \fIarrayName\fR. \fBArrayName\fR must be an array accessible to the caller of \fBparray\fR. It may be either local or global. .SH "VARIABLES" .PP The following global variables are defined or used by the procedures in the Tcl library: .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 disk. .TP \fBauto_noexec\fR If set to any value, then \fBunknown\fR will not attempt to auto-exec any commands. .TP \fBauto_noload\fR 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. .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 returned by the command \fBinfo library\fR). If this variable isn't 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. This variable is only used if \fBauto_path\fR is not defined. .TP \fBunknown_active\fR This variable is set by \fBunknown\fR to indicate that it is active. It is used to detect errors where \fBunknown\fR recurses on itself infinitely. The variable is unset before \fBunknown\fR returns. .SH KEYWORDS auto-exec, auto-load, library, unknown