Problem with running external process

[ToMasz]

No, no, that wasn't my intention (I'm just not conscious enough what's
going on with these fork, exec, spawn.. functions).
My parent process should start the child process and go back to it's
tasks. Before executing it for the next time the parent should check if
the previous child process is done and start it again.

Is it what these lines do?

os.spawnlp(os.P_NOWAIT,'ext_script.py','')
os.waitpid(-1, os.WNOHANG)