pythonmultithreadingdaemonpython-multithreading

Daemon Threads Explanation


In the Python documentation it says:

A thread can be flagged as a "daemon thread". The significance of this flag is that the entire Python program exits when only daemon threads are left. The initial value is inherited from the creating thread.

Does anyone have a clearer explanation of what that means or a practical example showing where you would set threads as daemonic?

Clarify it for me: so the only situation you wouldn't set threads as daemonic, is when you want them to continue running after the main thread exits?


Solution

  • Some threads do background tasks, like sending keepalive packets, or performing periodic garbage collection, or whatever. These are only useful when the main program is running, and it's okay to kill them off once the other, non-daemon, threads have exited.

    Without daemon threads, you'd have to keep track of them, and tell them to exit, before your program can completely quit. By setting them as daemon threads, you can let them run and forget about them, and when your program quits, any daemon threads are killed automatically.