#/usr/bin/perl
use strict;
use warnings;

sub trace
{
  my @lst;
  my $deep=2;
  while(my ($package, $filename, $line, $subroutine)=caller($deep++))
  { push @lst, "at $filename, Line $line (Package:$package, Sub:$subroutine)\n"; }
  print STDERR "\n\n",reverse(@lst);
  print @_ if(@_);
}
$SIG{__DIE__} = sub{ trace() };
$SIG{__WARN__} = sub{ trace(@_) };

a();
########################################################################

sub a{ b() }
sub b{ c() }
sub c{ IN::d() }
package IN;
sub d{ e() }
sub e
{
  warn("UPS");
  f();
}
sub f{ IN::IN::g() }
package IN::IN;
sub g{ h() }
sub h{ die("BOOM") }