Pierre Barbier de Reuille <[EMAIL PROTECTED]> writes:
Ville Vainio a ecrit :
"Bastian" == Bastian Hammer <[EMAIL PROTECTED]> writes:
Bastian> Now I have to make sure, that both threads are
Bastian> synchronal, 1 thread edits something and the other is Bastian> blocked until the first thread is ready. Bastian> Isn't it a good idea to do this with a semaphore?
Semaphore will do, but this is a classical use case for threading.Lock.
There should be lots of stuff regarding locks (or more googleably, "mutexes") on the net.
I don't agree. Mutexes (or locks) are best suited for critical sections (ie. sections that cannot be run by many thread at the same time).
Please don't add even more confusion to the issue. Mutex conceptually is designed to be used for MUTual EXclusion of access to a resource (e.g., a peace of data). While critical section could be implemented using mutex, the mutex itself is more general concept. Besides, the rule of thumb using mutexes is: "protect data, not program code."
My answer to OP's question is: use either lock (mutex) or semaphore. I'd probably use semaphore as mutexes are usually optimized for the case when contention probability is low (i.e., they usually shouldn't be locked for a long time).
My point is : semaphore is more complex than what he needs. Event are simpler and just do what he needs : block one thread until another one finished some jobs and launchs the event (have a look at my example).
Afterward, I agree that the concept of mutex is the most general : you can implement every other kind of lock using just mutexes.
Pierre -- http://mail.python.org/mailman/listinfo/python-list
