'\" '\" Copyright (c) 1989-1993 The Regents of the University of California. '\" Copyright (c) 1994-1997 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: @(#) Eval.3 1.21 97/01/22 14:22:03 '\" '\" 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 ?version? ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. The first argument is ignored and used for recording '\" the version when the .VS was added, so that the sidebars can be '\" found and removed when they reach a certain age. If another 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 1.9 97/08/22 18:50:59 '\" '\" # 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 !"\\$2"" .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 Tcl_Eval 3 7.0 Tcl "Tcl Library Procedures" .BS .SH NAME Tcl_Eval, Tcl_VarEval, Tcl_EvalFile, Tcl_GlobalEval \- execute Tcl commands .SH SYNOPSIS .nf \fB#include \fR .sp int \fBTcl_Eval\fR(\fIinterp, cmd\fR) .sp int \fBTcl_VarEval\fR(\fIinterp, string, string, ... \fB(char *) NULL\fR) .sp int \fBTcl_EvalFile\fR(\fIinterp, fileName\fR) .sp int \fBTcl_GlobalEval\fR(\fIinterp, cmd\fR) .SH ARGUMENTS .AS Tcl_Interp **termPtr; .AP Tcl_Interp *interp in Interpreter in which to execute the command. A string result will be stored in \fIinterp->result\fR. .AP char *cmd in Command (or sequence of commands) to execute. Must be in writable memory (\fBTcl_Eval\fR makes temporary modifications to the command). .AP char *string in String forming part of Tcl command. .AP char *fileName in Name of file containing Tcl command string. .BE .SH DESCRIPTION .PP All four of these procedures execute Tcl commands. \fBTcl_Eval\fR is the core procedure and is used by all the others. It executes the commands in the script held by \fIcmd\fR until either an error occurs or it reaches the end of the script. .PP Note that \fBTcl_Eval\fR and \fBTcl_GlobalEval\fR have been largely replaced by the object-based procedures \fBTcl_EvalObj\fR and \fBTcl_GlobalEvalObj\fR. Those object-based procedures evaluate a script held in a Tcl object instead of a string. The object argument can retain the bytecode instructions for the script and so avoid reparsing the script each time it is executed. \fBTcl_Eval\fR is implemented using \fBTcl_EvalObj\fR but is slower because it must reparse the script each time since there is no object to retain the bytecode instructions. .PP The return value from \fBTcl_Eval\fR is one of the Tcl return codes \fBTCL_OK\fR, \fBTCL_ERROR\fR, \fBTCL_RETURN\fR, \fBTCL_BREAK\fR, or \fBTCL_CONTINUE\fR, and \fIinterp->result\fR will point to a string with additional information (a result value or error message). If an error occurs during compilation, this return information describes the error. Otherwise, this return information corresponds to the last command executed from \fIcmd\fR. .PP \fBTcl_VarEval\fR takes any number of string arguments of any length, concatenates them into a single string, then calls \fBTcl_Eval\fR to execute that string as a Tcl command. It returns the result of the command and also modifies \fIinterp->result\fR in the usual fashion for Tcl commands. The last argument to \fBTcl_VarEval\fR must be NULL to indicate the end of arguments. .PP \fBTcl_EvalFile\fR reads the file given by \fIfileName\fR and evaluates its contents as a Tcl command by calling \fBTcl_Eval\fR. It returns a standard Tcl result that reflects the result of evaluating the file. If the file couldn't be read then a Tcl error is returned to describe why the file couldn't be read. .PP During the processing of a Tcl command it is legal to make nested calls to evaluate other commands (this is how procedures and some control structures are implemented). If a code other than \fBTCL_OK\fR is returned from a nested \fBTcl_Eval\fR invocation, then the caller should normally return immediately, passing that same return code back to its caller, and so on until the top-level application is reached. A few commands, like \fBfor\fR, will check for certain return codes, like \fBTCL_BREAK\fR and \fBTCL_CONTINUE\fR, and process them specially without returning. .PP \fBTcl_Eval\fR keeps track of how many nested \fBTcl_Eval\fR invocations are in progress for \fIinterp\fR. If a code of \fBTCL_RETURN\fR, \fBTCL_BREAK\fR, or \fBTCL_CONTINUE\fR is about to be returned from the topmost \fBTcl_Eval\fR invocation for \fIinterp\fR, it converts the return code to \fBTCL_ERROR\fR and sets \fIinterp->result\fR to point to an error message indicating that the \fBreturn\fR, \fBbreak\fR, or \fBcontinue\fR command was invoked in an inappropriate place. This means that top-level applications should never see a return code from \fBTcl_Eval\fR other then \fBTCL_OK\fR or \fBTCL_ERROR\fR. .SH "SEE ALSO" Tcl_EvalObj, Tcl_GlobalEvalObj .SH KEYWORDS command, execute, file, global, object, object result, variable