Hello, I have a case of multithreaded program where under some condition, I would want to test the flag of the Event object and clear it atomically. This would allow me to know which thread has actually cleared the flag and thus should perform some more work before setting it again. The isSet method is of course not good enough because it's subject to race conditions. (Not even sure the GIL would make it safe.) The changes to threading.py would be pretty trivial: @@ -515,8 +515,10 @@ """ with self._cond: + prevflag = self._flag self._flag = True self._cond.notify_all() + return prevflag def clear(self): """Reset the internal flag to false. @@ -526,7 +528,9 @@ """ with self._cond: + prevflag = self._flag self._flag = False + return prevflag def wait(self, timeout=None): """Block until the internal flag is true. What do you think about it? Best regards, Celelibi