[Python-Dev] Thread safety of deques (original) (raw)

Moore, Paul Paul.Moore at atosorigin.com
Mon Jul 19 17:54:01 CEST 2004

The documentation for the collections.deque type states that "Deques support thread-safe, memory efficient appends and pops from either side of the deque". I'm not clear what the implication of saying that these operations are "thread-safe" is.

To contrast, list.append() does not claim thread safety. Should I therefore conclude that to append an item in a thread-safe manner to a list requires a mutex, but not for a deque?

Overall, the documentation does not tend to state what operations are "atomic" in thread-safety terms. Continuing that trend, it may be better not to make any statement about deques. If we do, then not saying anything about other types seems to imply that they are not thread-safe. Which may well be true, but if so should probably be explicit, once we start making thread safety claims of other data structures.

This way to the slippery slope... :-)

Paul.

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