On Mon, Feb 10, 2014 at 1:45 AM, Roy Smith <r...@panix.com> wrote: > In article <mailman.6578.1391943647.18130.python-l...@python.org>, > Skip Montanaro <s...@pobox.com> wrote: > >> As the author of lockfile, I can tell you it only implements advisory >> locking. All programs needing to access the locked resources must >> cooperate. > > This is true of all mutexes, no? >
Not quite all; mandatory locks actually prevent other access. But they require support from whatever makes the resource available - most commonly, the file system - where cooperative locking doesn't. I've written a number of cooperative locking systems in the past (eg to protect a network resource, when the mounted file system didn't offer the sort of locking I needed), and they're usually the way to go when there's anything complicated going on. What, all mutexes? Yes, all mutexes! What, all? Well.... nearly all! -- with apologies to WS Gilbert, HMS Pinafore, and the Pirates of Penzance ChrisA -- https://mail.python.org/mailman/listinfo/python-list
