I'm working on a module which traps warning and fatal signals in the BEGIN block:

  $SIG{__WARN__} = \&foo;
  $SIG{__DIE__}  = \&bar;

All this works fine (well, I gotta work on trapping dies in `eval' but that's a separate issue). What doesn't work is when I use another module that also traps these, such as CGI::Carp.

If I `use' my module before CGI::Carp, my traps are lost. Likewise if I use mine after CGI::Carp, I kill its traps.

I've tried something like the following:

  if ($SIG{__WARN__}) {
    my $previous = $SIG{__WARN__};
    $SIG{__WARN__} = sub {
        # do my stuff
        goto &$previous;
    };
  }
  else
  # blah blah

but this doesn't work! It repeatedly calls my handler over and over, as if $previous contained a reference to my code (I've debugged it and found $previous only contains something when a module such as CGI::Carp has trapped the signal).

So what am I doing wrong here?

In reply to How can two modules latch onto $SIN{__WARN__} or $SIG{__DIE__}? by rrwo

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