"burton666@xxxxxxxxx" <burton666@xxxxxxxxx> wrote:
> I was looking through BLocker's source code, and I noticed this:
>
> int32 oldBenaphoreCount = atomic_add(&fBenaphoreCount, 1);
> if (oldBenaphoreCount > 0) {
> etc. etc.
>
> Should this be
> if (atomic_add(&fBenaphoreCount, 1))
> etc. etc. ?
>
> Since the value returned from atomic_add could change before
> executing the if.
No no, atomic_add() returns the old value of fBenaphoreCount and at the
same time, atomically sets it to another value (adds one).
The "oldBenaphoreCount" variable won't be changed anymore - it reflects
the state at the time atomic_add() was executed, and we are only
interested in that state (if it has changed in the meantime, the other
thread will block, but we don't have to).
Adios...
Axel.
