Re^2: SIG{__WARN__}, Storable, and Log::Agent...

That explains a lot. "Strange action at a distance" is a lot more polite than what I would call it though. Storable is a pretty important core module, and the resulting error message makes absolutely no sense to the user.

When perlvar says "Do not use this to ..., or as a bizarre substitute for overriding CORE::GLOBAL::die()", what exactly do they mean? I though that the entire purpose of $SIG{__DIE__} was exactly for overriding the global die() functionality.

Perhaps my question should permute into this:

I have a ton of code, much of it in modules, which in turn use other modules I've written, which in turn also use some 3rd party and/or core modules. When I execute the top level scripts that drag all of this in, I would like to enforce that all die()s and warn()s that happen, regardless of the module they occur in, call my special die/warn handlers to handle all of the error output in a consistent fashion.

Since there are many top-level scripts, I would prefer to wrap the die/warn-handling code into another module, say named "MyProject::ErrorHandler", which I include in the top level scripts and/or the various modules I have control over. How does one go about accomplishing this correctly, without screwing up die()'s that occur in evals, which some modules (even my own) depend on.

Comment on Re^2: SIG{__WARN__}, Storable, and Log::Agent...

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Re^3: SIG{__WARN__}, Storable, and Log::Agent... by ph713 (Pilgrim) on May 06, 2005 at 21:23 UTC
`#!/usr/bin/perl -w use strict; use warnings; BEGIN { $SIG{__DIE__} = sub { die @_ if !defined($^S); die @_ if $^S; print "SIG{__DIE__} handling the following error: " . $_[0]; exit(99); }; } use Storable; print "This script sucks\n"; die "I will now die because I suck";` [download] ^^^ This seems to do what I want to do. perldoc -f die seems to think I should only need the "die @_ if $^S", but I've found the line before it with "die @_ if !defined($^S)" is also neccesary, at least in this example. According to perldoc perlvar: $^S Current state of the interpreter. $^S State --------- ------------------- undef Parsing module/eval true (1) Executing an eval false (0) Otherwise The first state may happen in $SIG{__DIE__} and $SIG{__WARN__} handlers. In my case, it seems only the "0" case is what I want to be handling directly.	[reply] [d/l]

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Re^3: SIG{__WARN__}, Storable, and Log::Agent...
by ph713 (Pilgrim) on May 06, 2005 at 21:23 UTC

#!/usr/bin/perl -w

use strict;
use warnings;

BEGIN {
  $SIG{__DIE__} = sub {
    die @_ if !defined($^S);
    die @_ if $^S;
    print "SIG{__DIE__} handling the following error: " . $_[0];
    exit(99);
  };
}
use Storable;

print "This script sucks\n";
die "I will now die because I suck";
[download]

 $^S     Current state of the interpreter.

                   $^S         State
                   ---------   -------------------
                   undef       Parsing module/eval
                   true (1)    Executing an eval
                   false (0)   Otherwise

               The first state may happen in $SIG{__DIE__} and $SIG{__WARN__} handlers.

[reply]
[d/l]