[Chris Withers]
Anyone know what the difference is between Zope's ThreadLock module and the standard python Lock objects from the threading module?
A ThreadLock.ThreadLock is reentrant but a threading.Lock isn't: once a thread has acquired a ThreadLock, that thread can acquire that ThreadLock again, any number of times, without blocking. This is useful, e.g., for a lock that wants to give a thread exclusive access to an object's methods, where some of the methods may invoke other methods of the object. That isn't true of a threading.Lock: each attempt to acquire an already-acquired Lock blocks until the Lock is released, regardless of which thread may be trying to acquire. The other difference is that an acquired ThreadLock can be released only by the thread that acquired it, while any thread can release an acquired threading.Lock. A threading.RLock (note the "R") has the same semantics as a ThreadLock.ThreadLock, though. Zope's ThreadLock.c predates Python's threading.py, and Python didn't offer any form of reentrant lock before threading.py (although you could build your own on top of Python's thread module's lock, which is in fact how threading.RLock and ThreadLock.ThreadLock are implemented).