On Apr 25, 2004, at 6:52 AM, Peter Dimov wrote:
In the std::locale implementation I am careful to wrap each use of the locale implementation with a mutex lock. I believe I would have to do this whether or not shared_ptr protected its count. And yet std::locale is just a library, not an application.
I am not sure whether you can skip the count synchronization here. Even though you do not expose a shared_ptr directly, the user can still copy a std::locale at will. When two threads copy the same std::locale at the same time, a non-synchronized count leads to undefined behavior.
I don't think I was clear. The access is synchronized. The synchronization happens at the locale level, making the synchronization at the shared_ptr level redundant. I need to synchronize more than just the counts in the shared_ptr, namely access to the stuff that the shared_ptr is pointing to. -Howard