freebsd-nq/contrib/tcl/doc/AllowExc.3

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'\" Copyright (c) 1989-1993 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.
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'\" SCCS: @(#) AllowExc.3 1.5 96/03/25 19:55:47
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.so man.macros
.TH Tcl_AllowExceptions 3 7.4 Tcl "Tcl Library Procedures"
.BS
.SH NAME
Tcl_AllowExceptions \- allow all exceptions in next script evaluation
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
\fBTcl_AllowExceptions\fR(\fIinterp\fR)
.SH ARGUMENTS
.AS Tcl_Interp *doublePtr
.AP Tcl_Interp *interp in
Interpreter in which script will be evaluated.
.BE
.SH DESCRIPTION
.PP
If a script is evaluated at top-level (i.e. no other scripts are
pending evaluation when the script is invoked), and if the script
terminates with a completion code other than TCL_OK, TCL_CONTINUE
or TCL_RETURN, then Tcl normally converts this into a TCL_ERROR
return with an appropriate message.
.PP
However, if \fBTcl_AllowExceptions\fR is invoked immediately before
calling a procedure such as \fBTcl_Eval\fR, then arbitrary completion
codes are permitted from the script, and they are returned without
modification.
This is useful in cases where the caller can deal with exceptions
such as TCL_BREAK or TCL_CONTINUE in a meaningful way.
.SH KEYWORDS
continue, break, exception, interpreter