According to the perlvar docs for $SIG{__DIE__}:

Due to an implementation glitch, the $SIG{__DIE__} hook is called even inside an eval(). Do not use this to rewrite a pending exception in $@ , or as a bizarre substitute for overriding CORE::GLOBAL::die() . This strange action at a distance may be fixed in a future release so that $SIG{__DIE__} is only called if your program is about to exit, as was the original intent. Any other use is deprecated.

However, I find this particular behaviour useful. For instance, in my mod_perl application, pretty much all the code is wrapped in an eval which lets me return a nice error page to the user. Because of this glitch, I am able to inflate an uncaught exception into an error object, with attached stacktrace:


#===================================
sub uncaught_error {
#===================================
    die @_ 
        if ref $_[0]                                # already an excep
+tion object
           || ! defined $^S;                        # code is being co
+mpiled

    my ($class) = caller(0);                        # throw() does the
+ work of inflating 
    @_ = ( $class, 'Uncaught', join( '', @_ ) );    # an error message
+ into an exception object
    goto $class->can('throw') || \&throw;           # of the relevant 
+class
}

$SIG{__DIE__} = \&uncaught_error;

[download]

Once this 'glitch' is fixed, the above code will no longer work (as in it will no longer give me a stack trace from the place where the error occurred) . Is there a better (not-about-to-be-deprecated) way to do this?

thanks

Clint

UPDATE: Added some comments to the code

In reply to Deprecated use of $SIG{__DIE__} is useful by clinton

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