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| -rw-r--r-- | doc/exit.n | 24 |
1 files changed, 23 insertions, 1 deletions
@@ -5,7 +5,7 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: exit.n,v 1.3 2000/09/07 14:27:47 poenitz Exp $ +'\" RCS: @(#) $Id: exit.n,v 1.4 2004/05/24 13:00:55 dkf Exp $ '\" .so man.macros .TH exit n "" Tcl "Tcl Built-In Commands" @@ -23,6 +23,28 @@ Terminate the process, returning \fIreturnCode\fR to the system as the exit status. If \fIreturnCode\fR isn't specified then it defaults to 0. +.SH EXAMPLE +Since non-zero exit codes are usually interpreted as error cases by +the calling process, the \fBexit\fR command is an important part of +signalling that something fatal has gone wrong. This code fragment is +useful in scripts to act as a general problem trap: +.CS +proc main {} { + # ... put the real main code in here ... +} + +if {[catch {main} msg]} { + puts stderr "unexpected script error: $msg" + if {[info exist env(DEBUG)]} { + puts stderr "---- BEGIN TRACE ----" + puts stderr $errorInfo + puts stderr "---- END TRACE ----" + } + + # Reserve code 1 for "expected" error exits... + exit 2 +} +.CE .SH "SEE ALSO" exec(n), tclvars(n) |