Disregard this post. Seems I havent got the OPs question right.

That is what Carp is for:

#!/usr/bin/perl

use Carp qw(confess cluck);
use strict;

$SIG{__DIE__}  = \&confess;
$SIG{__WARN__} = \&cluck;

a();

sub a {
    print "in a\n";
    b("foo");
} 

sub b {
    warn "got wrong value $_[0]\n";
    c("bar");
} 

sub c {
    print "in c\n";
    die "dying because of $_[0]!\n";
}
[download]

in a
got wrong value foo
 at foo.pl line 17
        main::b('foo') called at foo.pl line 13
        main::a() called at foo.pl line 9
in c
dying because of bar!
 at foo.pl line 23
        main::c('bar') called at foo.pl line 18
        main::b('foo') called at foo.pl line 13
        main::a() called at foo.pl line 9
[download]

With that backtrace you know what's going wrong,and where.

If you want to keep your code running and just examine the errors, you could write a sub that just stores the warnings in an array for later examination, and assign a reference of that to $SIG{__WARN__}.

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}