diff options
Diffstat (limited to 'doc/bgerror.n')
| -rw-r--r-- | doc/bgerror.n | 64 |
1 files changed, 36 insertions, 28 deletions
diff --git a/doc/bgerror.n b/doc/bgerror.n index 3f946c3..510a523 100644 --- a/doc/bgerror.n +++ b/doc/bgerror.n @@ -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: bgerror.n,v 1.2 1998/09/14 18:39:51 stanton Exp $ +'\" RCS: @(#) $Id: bgerror.n,v 1.3 2000/06/26 23:23:13 ericm Exp $ '\" .so man.macros .TH bgerror n 7.5 Tcl "Tcl Built-In Commands" @@ -31,38 +31,46 @@ with the \fBafter\fR command, then it is a background error. For a non-background error, the error can simply be returned up through nested Tcl command evaluations until it reaches the top-level code in the application; then the application can report the error -in whatever way it wishes. -When a background error occurs, the unwinding ends in -the Tcl library and there is no obvious way for Tcl to report -the error. +in whatever way it wishes. When a background error occurs, the +unwinding ends in the Tcl library and there is no obvious way for Tcl +to report the error. .PP When Tcl detects a background error, it saves information about the -error and invokes the \fBbgerror\fR command later as an idle event handler. -Before invoking \fBbgerror\fR, Tcl restores the \fBerrorInfo\fR -and \fBerrorCode\fR variables to their values at the time the -error occurred, then it invokes \fBbgerror\fR with -the error message as its only argument. -Tcl assumes that the application has implemented the \fBbgerror\fR -command, and that the command will report the error in a way that -makes sense for the application. Tcl will ignore any result returned -by the \fBbgerror\fR command as long as no error is generated. +error and invokes the \fBbgerror\fR command later as an idle event +handler. Before invoking \fBbgerror\fR, Tcl restores the +\fBerrorInfo\fR and \fBerrorCode\fR variables to their values at the +time the error occurred, then it invokes \fBbgerror\fR with the error +message as its only argument. Tcl assumes that the application has +implemented the \fBbgerror\fR command, and that the command will +report the error in a way that makes sense for the application. Tcl +will ignore any result returned by the \fBbgerror\fR command as long +as no error is generated. .PP -If another Tcl error occurs within the \fBbgerror\fR command -(for example, because no \fBbgerror\fR command has been defined) -then Tcl reports the error itself by writing a message to stderr. +If another Tcl error occurs within the \fBbgerror\fR command (for +example, because no \fBbgerror\fR command has been defined) then Tcl +reports the error itself by writing a message to stderr. .PP -If several background errors accumulate before \fBbgerror\fR -is invoked to process them, \fBbgerror\fR will be invoked once -for each error, in the order they occurred. -However, if \fBbgerror\fR returns with a break exception, then -any remaining errors are skipped without calling \fBbgerror\fR. +If several background errors accumulate before \fBbgerror\fR is +invoked to process them, \fBbgerror\fR will be invoked once for each +error, in the order they occurred. However, if \fBbgerror\fR returns +with a break exception, then any remaining errors are skipped without +calling \fBbgerror\fR. .PP -Tcl has no default implementation for \fBbgerror\fR. -However, in applications using Tk there is a default -\fBbgerror\fR procedure -which posts a dialog box containing -the error message and offers the user a chance to see a stack -trace showing where the error occurred. +Tcl has no default implementation for \fBbgerror\fR. However, in +applications using Tk there is a default \fBbgerror\fR procedure which +posts a dialog box containing the error message and offers the user a +chance to see a stack trace showing where the error occurred. In +addition to allowing the user to view the stack trace, the dialog +provides an additional application configurable button which may be +used, for example, to save the stack trace to a file. By default, +this is the behavior associated with that button. This behavior can +be redefined by setting the option database values +\fB*ErrorDialog.function.text\fR, to specify the caption for the +function button, and \fB*ErrorDialog.function.command\fR, to specify +the command to be run. The text of the stack trace is appended to the +command when it is evaluated. If either of these options is set to +the empty string, then the additional button will not be displayed in +the dialog. .SH KEYWORDS background error, reporting |