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1.1       root        1: '\" Copyright 1989 Regents of the University of California
                      2: '\" Permission to use, copy, modify, and distribute this
                      3: '\" documentation for any purpose and without fee is hereby
                      4: '\" granted, provided that this notice appears in all copies.
                      5: '\" The University of California makes no representations about
                      6: '\" the suitability of this material for any purpose.  It is
                      7: '\" provided "as is" without express or implied warranty.
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                      9: '\" $Header: /sprite/src/lib/tcl/RCS/Tcl_Eval.man,v 1.3 90/01/07 16:02:10 ouster Exp $ SPRITE (Berkeley)
                     10: '\" 
                     11: .so \*(]ltmac.sprite
                     12: .HS Tcl_Eval tcl
                     13: .BS
                     14: .SH NAME
                     15: Tcl_Eval \- execute a Tcl command string
                     16: .SH SYNOPSIS
                     17: .nf
                     18: \fB#include <tcl.h>\fR
                     19: .sp
                     20: int
                     21: \fBTcl_Eval\fR(\fIinterp, cmd, flags, termPtr\fR)
                     22: .SH ARGUMENTS
                     23: .AS Tcl_Interp **termPtr;
                     24: .AP Tcl_Interp *interp in
                     25: Interpreter in which to execute the command.  String result will be
                     26: stored in \fIinterp->result\fR.
                     27: .AP char *cmd in
                     28: Command (or sequence of commands) to execute.
                     29: .AP char flags in
                     30: Either \fBTCL_BRACKET_TERM\fR or 0.
                     31: .VS
                     32: If 0, then \fBTcl_Eval\fR will process commands from \fIcmd\fR until
                     33: it reaches the null character at the end of the string;  newlines
                     34: will be treated as command separators.  If \fBTCL_BRACKET_TERM\fR,
                     35: then \fBTcl_Eval\fR will process comands from \fIcmd\fR until either it
                     36: reaches a null character or it encounters a close bracket that isn't
                     37: backslashed or enclosed in braces, at which
                     38: point it will return;  newlines will treated as white space, not as
                     39: command separators.  Under normal conditions, \fIflags\fR should be 0.
                     40: .VE
                     41: .AP char **termPtr out
                     42: If 
                     43: .VS
                     44: \fItermPtr\fR is non-NULL, \fBTcl_Eval\fR fills in *\fItermPtr\fR with
                     45: the address of the character just after the last one in the last command
                     46: successfully executed (normally the null character at the end of \fIcmd\fR).
                     47: If an error occurs in the first command in \fIcmd\fR, then \fI*termPtr\fR
                     48: will be set to \fIcmd\fR.
                     49: .VE
                     50: .BE
                     51: 
                     52: .SH DESCRIPTION
                     53: .PP
                     54: \fBTcl_Eval\fR parses commands from \fIcmd\fR and executes them in
                     55: order until either an error occurs or \fBTcl_Eval\fR reaches a terminating
                     56: character (']' or '\0', depending on the value of \fIflags\fR).
                     57: The return value from \fBTcl_Eval\fR is one
                     58: of the Tcl return codes \fBTCL_OK\fR, \fBTCL_ERROR\fR, \fBTCL_RETURN\fR, \fBTCL_BREAK\fR, or
                     59: \fBTCL_CONTINUE\fR, and \fIinterp->result\fR will point to
                     60: a string with additional information (result value or error message).
                     61: This return information corresponds to the last command executed from
                     62: \fIcmd\fR.
                     63: .PP
                     64: During the processing of a command it is legal to make nested
                     65: calls to \fBTcl_Eval\fR (this is how conditionals, loops, and procedures
                     66: are implemented).  If a code other than
                     67: \fBTCL_OK\fR is returned from a nested \fBTcl_Eval\fR invocation, then the
                     68: caller should normally return immediately, passing that same
                     69: return code back to its caller, and so on until the top-level application is
                     70: reached.  A few commands, like \fBfor\fR, will check for certain
                     71: return codes, like \fBTCL_BREAK\fR and \fBTCL_CONTINUE\fR, and process them
                     72: specially without returning.
                     73: .PP
                     74: \fBTcl_Eval\fR keeps track of how many nested Tcl_Eval invocations are
                     75: in progress for \fIinterp\fR.
                     76: If a code of \fBTCL_RETURN\fR, \fBTCL_BREAK\fR, or \fBTCL_CONTINUE\fR is
                     77: about to be returned from the topmost \fBTcl_Eval\fR invocation for
                     78: \fIinterp\fR, then \fBTcl_Eval\fR converts the return code to \fBTCL_ERROR\fR
                     79: and sets \fIinterp->result\fR to point to an error message indicating that
                     80: the \fBreturn\fR, \fBbreak\fR, or \fBcontinue\fR command was
                     81: invoked in an inappropriate place.  This means that top-level
                     82: applications should never see a return code from \fBTcl_Eval\fR other then
                     83: \fBTCL_OK\fR or \fBTCL_ERROR\fR.
                     84: 
                     85: .SH KEYWORDS
                     86: command, execute, interpreter

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