[patch] Make std::tr1::shared_ptr thread-safe.

[Alexander Terekhov]

[...  __release/acquire_memory_barrier() ...]

> The only reliable implementation of these barriers that I see 
> is an empty pthread_mutex_lock/pthread_mutex_unlock pair. 

Nope. That won't work. It just proves once again that non-label 
notation for acquire/release (and others more relaxed 
unidirectional) constraints sucks miserably. It's akin to 
abuse of pthread_barrier_wait().

http://www.opengroup.org/austin/mailarchives/ag/msg07595.html
http://www.opengroup.org/austin/mailarchives/ag/msg07604.html
http://www.opengroup.org/austin/mailarchives/ag/msg07593.html

Hth.

regards,
alexander.