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author | stanton <stanton> | 1998-11-09 22:52:44 (GMT) |
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committer | stanton <stanton> | 1998-11-09 22:52:44 (GMT) |
commit | 0b4519300089676213a88b349f37d77d6d707d34 (patch) | |
tree | 4e0c01dbb9b85124ec5336c4938c678e78c5c8e1 | |
parent | b17ee109b95c8282717d13c89e5d630ed6982d96 (diff) | |
download | tcl-0b4519300089676213a88b349f37d77d6d707d34.zip tcl-0b4519300089676213a88b349f37d77d6d707d34.tar.gz tcl-0b4519300089676213a88b349f37d77d6d707d34.tar.bz2 |
integrated documentation patch
-rw-r--r-- | doc/catch.n | 44 |
1 files changed, 29 insertions, 15 deletions
diff --git a/doc/catch.n b/doc/catch.n index 4afd314..3883b84 100644 --- a/doc/catch.n +++ b/doc/catch.n @@ -5,10 +5,10 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: catch.n,v 1.1.2.1 1998/09/24 23:58:29 stanton Exp $ +'\" RCS: @(#) $Id: catch.n,v 1.1.2.2 1998/11/09 22:52:44 stanton Exp $ '\" .so man.macros -.TH catch n "" Tcl "Tcl Built-In Commands" +.TH catch n "8.0" Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME @@ -19,22 +19,36 @@ catch \- Evaluate script and trap exceptional returns .SH DESCRIPTION .PP -The \fBcatch\fR command may be used to prevent errors from aborting -command interpretation. \fBCatch\fR calls the Tcl interpreter recursively -to execute \fIscript\fR, and always returns a TCL_OK code, regardless of -any errors that might occur while executing \fIscript\fR. The return -value from \fBcatch\fR is a decimal string giving the -code returned by the Tcl interpreter after executing \fIscript\fR. -This will be \fB0\fR (TCL_OK) if there were no errors in \fIscript\fR; -otherwise -it will have a non-zero value corresponding to one of the exceptional -return codes (see tcl.h for the definitions of code values). If the -\fIvarName\fR argument is given, then it gives the name of a variable; -\fBcatch\fR will set the variable to the string returned -from \fIscript\fR (either a result or an error message). +The \fBcatch\fR command may be used to prevent errors from aborting command +interpretation. \fBCatch\fR calls the Tcl interpreter recursively to +execute \fIscript\fR, and always returns without raising an error, +regardless of any errors that might occur while executing \fIscript\fR. +.PP +If \fIscript\fR raises an error, \fBcatch\fR will return a non-zero integer +value corresponding to one of the exceptional return codes (see tcl.h +for the definitions of code values). If the \fIvarName\fR argument is +given, then the variable it names is set to the error message from +interpreting \fIscript\fR. +.PP +If \fIscript\fR does not raise an error, \fBcatch\fR will return 0 +(TCL_OK) and set the variable to the value returned from \fIscript\fR. .PP Note that \fBcatch\fR catches all exceptions, including those generated by \fBbreak\fR and \fBcontinue\fR as well as errors. +.SH EXAMPLE + +\fBcatch\fR may be used in an \fBif\fR to branch based on the success +of a script. + +.DS +.CS +if { [catch {open $someFile w} fid] } { + puts stderr "Could not open $someFile for writing\\n$fid" + exit 1 +} +.CE +.DE + .SH KEYWORDS catch, error |