#!/usr/bin/perl -w

use strict;

my $num = '123'; # an external database ID, for example
warn "(PID $$) Beginning transaction #$num ";
eval {
    my $pid = fork();
    if ($pid) {
        warn "\t(PID $$) the parent does OK";
    }
    else {
        eval {
            warn "\t(PID $$) the child fails";
            die "\t(PID $$) Child process failure";
        };
        warn $@ if $@;
        exit;
    }
};
if ($@) {
    warn "(PID $$) Rolling back transaction #$num: died in eval with $@";
}
else {
    warn "(PID $$) Committing transaction #$num";
}