my $exit_sub = sub($) {
	die @_;
};
sub _overwrite_exit {
	my $package = $_[0];

	no warnings 'redefine';
	no strict 'refs';

	return if(*{"$package\::exit"}{CODE} && *{"$package\::exit"}{CODE} == $exit_sub);
	#print "\n$package";
	*{"$package\::exit"} = $exit_sub;
	
	foreach my $entry (keys %{"$package\::"}) {
		next if($entry !~ s/::$//);
		_overwrite_exit($entry);
	}
}
_overwrite_exit('main');
eval {
	print 123;
	exit(123);
};
print "Test: $@"; # never reached!