If you're on a *nix platform, "shared memory" is an additional way that a child can communicate with a parent. This is definitely the "road less travelled," since shared memory isn't available on all platforms.

Look in perlman:perlipc for the section on "SysV IPC". You'll find a short example, which might be enough to get you started.

A number of folks recommend IPC::Shareable, with which I have no experience.