Raymond Hettinger added the comment: The reliability issue for qsize(), empty(), and full() has nothing to do with their implementations. The problem is that any information obtained by those methods is potentially out-of-date by the time you try to use it (the LBYL problem). This is why multi-threaded programmers prefer (try: os.remove(fn) except OSError: pass) over (if os.path.exists(fn): os.remove(fn)) where the latter has an intrinsic race condition regardless of the implementation of os.path.exists().
One other note, self.not_full uses self.mutex internally. There is only one underlying lock for the whole queue implementation. Lastly, despite not having an underscore prefix in its name, q.not_full() is not part of the public API. Your "it hangs" example is part of the reason why ;-) In general, don't use full and empty tests to decide whether or not to do a put or get. Instead, just try the put or get directly and catch the exception if queue turns out to be full or empty. ---------- resolution: -> not a bug status: open -> closed _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue26958> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
