Check if current thread is main thread, in Python

The answers here are old and/or bad, so here's a current solution:

if threading.current_thread() is threading.main_thread():
    ...

This method is available since Python 3.4+.

The problem with threading.current_thread().name == 'MainThread' is that one can always do:

threading.current_thread().name = 'MyName'
assert threading.current_thread().name == 'MainThread' # will fail

Perhaps the following is more solid:

threading.current_thread().__class__.__name__ == '_MainThread'

Having said that, one may still cunningly do:

threading.current_thread().__class__.__name__ = 'Grrrr'
assert threading.current_thread().__class__.__name__ == '_MainThread' # will fail

But this option still seems better; "after all, we're all consenting adults here."

UPDATE:

Python 3.4 introduced threading.main_thread() which is much better than the above:

assert threading.current_thread() is threading.main_thread()

UPDATE 2:

For Python < 3.4, perhaps the best option is:

isinstance(threading.current_thread(), threading._MainThread)

Related