Re: Capturing Text from a die command

You can register a die handler in $SIG{__DIE__}. This example code probably won't work when you have multiple instances of Logger, and it will clobber any die handler the user has set up. But it's a good start:

package Logger;

sub new {
    my $self = ...
    ...

    $SIG{__DIE__} = sub {
        my $msg = shift;
        $self->add($msg);
        die $msg;
    };

    return $self;
}
[download]

A more robust solution is to maintain a list of active Logger instances within the package, and set up just one die handler that writes to all of them.

package Logger;
our @instances;

sub new {
    my $self = ...;
    ...
    
    push @instances, $self;
    return $self;
}

$SIG{__DIE__} = sub {
    my $msg = shift;
    $_->add($msg) for @instances;
}
[download]

You may also want to take care to not clobber existing die handlers, but I don't know a whole lot about that. I'll leave it to the pros ;)

blokhead

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Re: Re: Capturing Text from a die command by or10n (Initiate) on May 14, 2004 at 18:24 UTC
Works like a charm, I appreciate it. You also just gave me a new subject to read up on. Thanks!	[reply]
Re: Re: Capturing Text from a die command by hv (Prior) on May 16, 2004 at 13:13 UTC
Note that `die` is often caught in `eval`, and you usually don't want to log such fake deaths. You can avoid that by checking `$^S`: `$SIG{__DIE__} = sub { die @_ if $^S; ... };` [download] Note that the fake SIG handlers `__DIE__` and `__WARN__` have special handling: the handler is suspended while running it, so calling `die()` within the die handler does the right thing. This still won't necessarily do the right thing for the commonish idiom of 'load module if available': `BEGIN { $module_loaded = eval { require Some::Module }; }` [download] since in that context `$^S` is set to `undef`; I'm not aware of any easy way to determine in that case whether or not the failed require is happening inside an `eval`. Hugo	[reply] [d/l] [select]