Re: Object-oriented multithreading

Pete Becker <>
6 Sep 2006 10:49:45 -0400
Alan McKenney wrote:

One of the big issues is synchronization, especially
of memory reads and writes. For example, if we have

int shared_value = 0;
Mutex shared_value_mutex;

void thread_a() {
   shared_value += 10;
void thread_b() {
   shared_value += 20;

and we assume that thread_b() starts before thread_a()
finishes, it is conceivable that thread_a() will release
the mutex, and thread_b() will get it, before thread_a's
update of shared_value propagates to the processor running

Maybe I'm missing the point. If the mutex is properly implemented, this
isn't a problem. Unlocking does a release, and locking does an acquire.
The result is that any values written by the unlocking thread are
visible to the locking thread.


  -- Pete

Author of "The Standard C++ Library Extensions: a Tutorial and Reference."
For more information about this book, see

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