Have you actually read the documentation of waitpid? If so, you'll know that you can do a non-blocking wait for any child processes, and if none have exited continue to process the rest of your app.
Ah, thank you for pointing out waitpid can be noblocking. I must have missed the WNOHANG portion when I looked at the man page. I ended up doing $SIG{CHLD} = 'IGNORE'; because I don't really care the exit code of my child.