[boost] Re: read/write mutexes and boost

From: Alexander Terekhov (terekhov_at_[hidden])
Date: 2003-10-20 17:46:53

"E. Gladyshev" wrote:
[...]
> If you are interested, we can discuss this condition
> in more details. It is not as straight forward as it might seem.

Real mutexes are designed for memory sharing, not isolation.

"Some have complained that POSIX mutexes don't allow a locking thread 
 to detect that the previous owner terminated "abnormally"... that's 
 because it wouldn't do any good to know without isolation between 
 the entities involved. With IPC mechanisms it makes sense to know, 
 because you can do something about it."

"Counting semaphores are well matched to dealing with 
 producer/consumer problems, including those that might exist 
 between threads of different processes, or between a signal handler 
 and a thread. In the former case, there may be LITTLE OR NO MEMORY 
 shared by the processes; in the latter case, one is not 
 communicating between co-equal threads, but between a thread and an 
 interrupt-like entity. It is for these reasons that IEEE Std 
 1003.1-2001 allows semaphores to be used by threads."

regards,
alexander.