Atomic operations (was Re: [Python-Dev] Why did Fredrik leave the party?) (original) (raw)

Barry A. Warsaw barry@python.org
Thu, 6 Feb 2003 09:11:47 -0500

"ESR" == Eric S Raymond <esr@thyrsus.com> writes:

ESR> I'm going to have to come out against this idea.  I think it
ESR> violates "explicit is better than implicit", and is
ESR> perilously close to being mere syntactic sugar.

Except that it's not, because of the lack of atomic acquire-and-enter-try.

You could probably code this specific example like so:

try:
lock.acquire()
dosomething()
finally:
try:
    lock.release()
except NotLocked:
    pass

but you still have the problem of ironclad resource release in other situations, such as the cursor opening scenario (I think) I posted before.

Brett (I think) suggested that there may be alternatives to a syntactic approach, e.g. one that prohibits thread switching between the resource acquisition and the entering of the try. That might be interesting to explore, but I worry about deadlock possibilities.

-Barry