What is a python thread

Question

I have several questions regarding Python threads.

1. Is a Python thread a Python or OS implementation?
2. When I use htop a multi-threaded script has multi

Answer 1

There are great answers to the question, but I feel the daemon threads question is still not explained in a simple fashion. So this answer refers just to the third question

"main thread terminates when all non-daemon threads are terminated."

So python daemon threads are not part of Python program if "the entire Python program exits when only daemon threads are left"?

If you think about what a daemon is, it is usually a service. Some code that runs in an infinite loop, that serves request, fill queues, accepts connections, etc. Other threads use it. It has no purpose when running by itself (in a single process terms).

So the program can't wait for the daemon thread to terminate, because it might never happen. Python will end the program when all non daemon threads are done. It also stops the daemon threads.

To wait until a daemon thread has completed its work, use the join() method. daemon_thread.join() will make Python to wait for the daemon thread as well before exiting. The join() also accepts a timeout argument.