| Win32::GUI::Carp - Redirect warnings and errors to Win32::GUI MessageBoxes |
Win32::GUI::Carp - Redirect warnings and errors to Win32::GUI MessageBoxes
use Win32::GUI::Carp qw/cluck/;
croak "Ribbit!";
confess "It was me: $!";
carp "How could you do that?";
warn "Duck!";
die "There's no hope...";
cluck "Don't do it.";
use Win32::GUI::Carp qw/warningsToDialog/;
warn "Warnings will be displayed in a pop-up dialog.";
use Win32::GUI::Carp qw/fatalsToDialog/;
die "Fatal error messages will be displayed in a pop-up dialog.";
use Win32::GUI::Carp qw/winwarn windie/;
winwarn "Warning in dialog.";
windie "Death in dialog.";
When Perl programs are run in a GUI environment, it is often desirable to have them run with no console attached. Unfortunately, this causes any warnings or errors to be lost. Worse, fatal errors can cause your program to silently disappear, forcing you to restart the program, attached to a console, and hope you can reproduce the error.
This module makes it easy to see any errors or warnings your
console-less program might produce by catching any errors
and/or warnings and displaying them in a pop-up dialog box
using Win32::GUI. It is similar in spirit to CGI::Carp's
fatalsToBrowser and warningsToBrowser special import
directives.
To cause errors or warnings to be displayed in a dialog,
simply specify one or more of the following options on the
use line, as shown in the SYNOPSIS.
warningsToDialogShow any warnings in a pop-up dialog box.
This option will cause a dialog box to be displayed
containing the text of the warnings. The type and style of
the dialog box can be configured (see CONFIGURATION).
Note that warnings are still sent to STDERR as well.
This option can also be activated or deactivated by setting
$Win32::GUI::Carp::WarningsToDialog to true or false,
respectively.
fatalsToDialogShow any fatal errors in a pop-up dialog box.
This option will cause a dialog box to be displayed
containing the text of the fatal error. The type and style
of the dialog box can be configured (see
CONFIGURATION). Note that errors are still sent to
STDERR as well.
This option can also be activated or deactivated by setting
$Win32::GUI::Carp::FatalsToDialog to true or false,
respectively.
immediateWarningsThis option controls whether all errors and warnings are displayed in a single dialog box or each get their own.
By default, warnings are buffered and not shown until just before the program terminates. At that point, any warnings and errors are shown together in a single dialog box. This is to cut down on the number of dialogs that have to be clicked through, although it means that you can't tell when a particular warning occurred.
If this option is specified, each warning and error message
will get its own dialog box which will be displayed as soon
as the warning or error occurs. Note that warnings are
always printed to STDERR as soon as they occur,
regardless of the state of this option.
Care should be taken when setting this option as it can cause a large number of dialog boxes to be created.
This option can also be activated or deactivated by setting
$Win32::GUI::Carp::ImmediateWarnings to true or false,
respectively.
winwarnRaises a warning, using a dialog. This function ignores the
state of warningsToDialog, although all other options are
observed (including ImmediateWarnings).
windieRaises a fatal error, using a dialog. This function ignores
the state of fatalsToDialog, although all other options
are observed.
syscarpExecutes a system command, just like system, but passes its its STDERR through any warn filters. In other words, if the command displays anything on STDERR, it will show up as a warning in the calling program, and thus display in a dialog (respecting warningsToDialog).
Note: The name of this function is subject to change, as I think it is somewhat misleading.
syscroakDoes the same thing as syscarp but dies if anything is sent to STDERR. It includes a message with the return value of the process.
Note: The name of this function is subject to change, as I think it is somewhat misleading.
The following variables control the style and type of dialog box used.
$Win32::GUI::Carp::DialogTitleA string that will be used as the title of the dialog box. This defaults to ``Warning'' when displaying warnings, and ``Error'' when displaying fatal errors.
$Win32::GUI::Carp::FatalFilterSet this to a reference to a subroutine that should be
called whenever a fatal error is about to be shown in a
dialog. The routine receives the error message in @_,
and if it returns a true value the error will be sent
to the dialog as normal, otherwise the dialog will not
be shown (though the error still propagates as normal).
$Win32::GUI::Carp::WarningFilterSet this to a reference to a subroutine that should be
called whenever a warning is about to be shown in a
dialog. The routine receives the warning message in
@_, and if it returns a true value the warning will
be sent to the dialog as normal, otherwise the dialog
will not be shown (though the warning still propagates
as normal).
This module relies on the following other modules to be installed:
__DIE__
and __WARN__. While it does save any previous handlers
and chain them properly, any new handler that is installed
will effectively disable the fatalsToDialog and
warningsToDialog options, respectively. Note that, as
this module's handlers are installed at compile time, it is
probable that any other handlers will be ``new.''
Especially if these changes aren't properly localized, this can cause us to miss many errors. There is a work-around, but it's a bit of an ugly hack, and involves tying %SIG, which seems dangerous. I may include it as an option in the future.
By default,carp(), croak() and confess() are
exported from Carp. If nothing is specified in the
import list (including the special *ToDialog and
immediateWarnings options), then Win32::GUI::Carp also
exports those functions. As soon as anything is given in
the import list, however, Exporter stops exporting the
things in @EXPORT (meaning the aforementioned functions
don't get exported).
There seems to be a bug on some versions of Win32
affecting syscarp and, moreso, syscroak where $?
is always set to 0, instead of the correct return value of
the called program.
Copyright 2002, Cory Johns.
This module is free software; you can redistribute and/or modify it under the same terms as Perl itself.
Address bug reports and comments to: Cory Johns <johnsca@cpan.org>
Carp, CGI::Carp, Win32::GUI
| Win32::GUI::Carp - Redirect warnings and errors to Win32::GUI MessageBoxes |