multiprocessing.queues.Queue.qsize raises NotImplementedError on macOS

[curonny]

cpython/Lib/multiprocessing/queues.py

Lines 124 to 126 in 1de4395

	def qsize(self):
	# Raises NotImplementedError on Mac OSX because of broken sem_getvalue()
	return self._maxsize - self._sem._semlock._get_value()

I use macos, i can't use multiprocessing for this reason

[ericvsmith]

You’d have to do some research to see if sem_getvalue is still broken on macOS. Maybe raise an issue with Apple?

[zware]

Also, as the documentation warns, the value returned by qsize isn't reliable even on platforms that implement sem_getvalue, and macOS might not be the only platform that doesn't. We have configure tests checking for sem_getvalue and whether it is "broken" for multiprocessing's purposes, so I presume that macOS's is still broken.

This doesn't seem like a bug worth chasing in Python, but if you can show that sem_getvalue does now work as expected in macOS and can provide a patch to fix it (probably by fixing the configure check), we can reopen the issue.

[jm-nab]

for anyone else that finds themselves here, a possible workaround can be found here: keras-team/autokeras#368 (comment)