package Handler;

use strict;
use warnings;
use Fcntl qw(:DEFAULT :flock);
use IO::Handle;
use Data::Dumper;

my $opts = {
   filename => './foo.bar',
   mode => O_WRONLY | O_APPEND | O_CREAT,
   umask => 0640,
};

my $self = bless $opts, __PACKAGE__;

open my $olderr, ">&STDERR" or die $!;
$self->{olderr} = \$olderr;
sysopen(STDERR, $self->{filename}, $self->{mode}, $self->{umask}) or die $!;
$self->{fh} = \*STDERR;
$self->{olddie} = $SIG{__DIE__};
$SIG{__DIE__} = \&_die_handler("bar foo");
STDERR->autoflush(1);

sub _die_handler {
   print {$self->{fh}} Dumper(\@_);
   exit(9);
}

1;

die "foo bar";