use strict;
use warnings;


use Carp;
use constant ERR_BACKTRACE => 1;

BEGIN {
    if (ERR_BACKTRACE) {
        *CORE::GLOBAL::warn = \&Carp::cluck;
        *CORE::GLOBAL::die  = \&Carp::confess;
    }
}


sub t2{
    warn "warn with trace";
}

sub t1 {
    t2(21,22,23);
    die "die with trace";
}

t1(11,12,13);