Re: [boost] [thread] condition suffering from lost wakup bug?

15 Sep 2005

      Roland Schwarz wrote:
...
4) a signal arrives, while gate still is closed
   Now is 0 < nWaitersToUnblock < N, correct?
   But 0 == nWaitersBlocked
   the signal results in a NO-OP and consequently the
   waiter from 3) will never get it to see - hence it is lost ??
Replacing the seuence on entry to wait:
sem_Wait (semBlockLock);
nWaitersBlocked++;
sem_post(semBlockLock);

by

atomic_increment(nWaitersBlocked);
sem_Wait (semBlockLock);
sem_Wait (semBlockLock);

would avoid loosing this signal, since the signal(bAll) function would
increment nWaitersToUnblock then.

Roland