Re: [Boost-users] weak_ptr and thread safety

Pavel Shevaev wrote:

Guys, could you please clarify whether the following usage of weak_ptr is thread safe:

//thread A: shared_ptr<Foo> p = wp.lock();

//thread B: p.reset();

p is local to thread A, so B can't reset it. // thread B: wp.reset(); is not safe (A reads wp, B writes wp). // before A and B shared_ptr<X> p( new X ); weak_ptr<X> wp( p ); // A shared_ptr<X> p2 = wp.lock(); // B p.reset(); is safe (A reads wp, B writes p).