'\" '\" Copyright (c) 1996-1997 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: EvalObj.3,v 1.2 2001/09/14 01:42:10 zlaski Exp $ '\" .so man.macros .TH Tcl_EvalObj 3 8.0 Tcl "Tcl Library Procedures" .BS .SH NAME Tcl_EvalObj, Tcl_GlobalEvalObj \- execute Tcl commands .SH SYNOPSIS .nf \fB#include <tcl.h>\fR .sp int \fBTcl_EvalObj\fR(\fIinterp, objPtr\fR) .sp int \fBTcl_GlobalEvalObj\fR(\fIinterp, objPtr\fR) .SH ARGUMENTS .AS Tcl_Interp **termPtr; .AP Tcl_Interp *interp in Interpreter in which to execute the command. The command's result will be stored in the interpreter's result object and can be retrieved using \fBTcl_GetObjResult\fR. .AP Tcl_Obj *objPtr in A Tcl object containing a command string (or sequence of commands in a string) to execute. .BE .SH DESCRIPTION .PP These two procedures execute Tcl commands. \fBTcl_EvalObj\fR is the core procedure and is used by \fBTcl_GlobalEvalObj\fR. It executes the commands in the script held by \fIobjPtr\fR until either an error occurs or it reaches the end of the script. If this is the first time \fIobjPtr\fR has been executed, its commands are compiled into bytecode instructions that are then executed if there are no compilation errors. .PP The return value from \fBTcl_EvalObj\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 a result object containing additional information (a result value or error message) that can be retrieved using \fBTcl_GetObjResult\fR. If an error occurs during compilation, this return information describes the error. Otherwise, this return information corresponds to the last command executed from \fIobjPtr\fR. .PP \fBTcl_GlobalEvalObj\fR is similar to \fBTcl_EvalObj\fR except that it processes the command at global level. This means that the variable context for the command consists of global variables only (it ignores any Tcl procedure that is active). This produces an effect similar to the Tcl command ``\fBuplevel 0\fR''. .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_EvalObj\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_EvalObj\fR keeps track of how many nested \fBTcl_EvalObj\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_EvalObj\fR invocation for \fIinterp\fR, it converts the return code to \fBTCL_ERROR\fR and sets the interpreter's result object 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_EvalObj\fR other then \fBTCL_OK\fR or \fBTCL_ERROR\fR. .SH "SEE ALSO" Tcl_GetObjResult, Tcl_SetObjResult .SH KEYWORDS command, execute, file, global, object, object result, variable