RE: [boost] Is shared_ptr really thread safe ?

From: Pete Becker (petebecker_at_[hidden])
Date: 2002-05-07 09:19:24

At 09:41 AM 5/7/2002 -0400, Richard Damon wrote:
>Atomic types may be accessed, with atomic operations, safely across multiple
>threads without the need of external interlocks.

For certain restricted meanings of "safely". <g> On a multi-processor 
system changes made in one thread often won't be visible to another thread 
running on a different processor because the two processors' caches aren't 
synchronized by this sort of operation. That's a part of the broader issue 
of memory visiblity, and this particular problem is solved by a mutex. 
Think of a mutex as an inter-thread sequence point: operations in a thread 
that unlocks a mutex are visible to a thread that subsequently locks the 
same mutex.

        -- Pete

Dinkumware, Ltd.
"Genuine Software"