Re: [boost] boost::shared_ptr<>::compare_and_swap()--AmIinsaneforwanting this?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2006-11-10 12:32:42

Peter Dimov wrote:

> bool compare_and_swap( shared_ptr & p, shared_ptr const & cmp,
> shared_ptr xchg )
> 
>    lock spinlock for p
>    bool r = p == cmp;
>    if( r ) p.swap( xchg );
>    unlock spinlock for p
>    return r;

This actually should be

    trylock spinlock for p
    if failed return false
    bool r = p == cmp;
    if( r ) p.swap( xchg );
    unlock spinlock for p
    return r;