python - Best way to implement a non-blocking wait?

Question

In python, if I want to keep a process or thread running forever, I can typically do this with an empty while loop:

while 1:
    pass

This, however, will eat an unfair amount of CPU process. Adding a short sleep would work:

import time
while 1:
    time.sleep(0.01)

Is there any best or cleaner way of doing this?

Answer 1

Given the rather bizarre requirements (a process that goes forever without using much CPU), this is reasonably compact:

import threading
dummy_event = threading.Event()
dummy_event.wait() 

...however, I fear I am succumbing to the temptation to solve your Y and not your X.

Besides which, this won't work if your platform doesn't provide the threading module. If you try to substitute the dummy_threading module, dummy_event.wait() returns immediately.

Update: if you are just keeping a parent process going for the sake of its subprocesses, you can use the wait()method on Popen objects, or the join() method on Process objects. Both of these methods will block indefinitely until the subprocess ends. If you're using some other subprocess API, there's bound to be equivalent functionality available. If not, get the PID of the process and use os.waitpid().