int pthread_barrier_wait (pthread_barrier_t * barrier) { int result; pthread_barrier_t b; ptw32_mcs_local_node_t node; if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) { return EINVAL; } ptw32_mcs_lock_acquire(&(*barrier)->lock, &node); b = *barrier; if (--b->nCurrentBarrierHeight == 0) { ptw32_mcs_node_transfer(&b->proxynode, &node); result = (b->nInitialBarrierHeight > 1 ? sem_post_multiple (&(b->semBarrierBreeched), b->nInitialBarrierHeight - 1) : 0); } else { ptw32_mcs_lock_release(&node); result = ptw32_semwait (&(b->semBarrierBreeched)); } if ((PTW32_INTERLOCKED_LONG)PTW32_INTERLOCKED_INCREMENT_LONG((PTW32_INTERLOCKED_LONGPTR)&b->nCurrentBarrierHeight) == (PTW32_INTERLOCKED_LONG)b->nInitialBarrierHeight) { ptw32_mcs_lock_release(&b->proxynode); if (0 == result) { result = PTHREAD_BARRIER_SERIAL_THREAD; } } return (result); }
int pthread_barrier_wait (pthread_barrier_t * barrier) { int result; pthread_barrier_t b; ptw32_mcs_local_node_t node; if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) { return EINVAL; } ptw32_mcs_lock_acquire(&(*barrier)->lock, &node); b = *barrier; if (--b->nCurrentBarrierHeight == 0) { /* * We are the last thread to arrive at the barrier before it releases us. * Move our MCS local node to the global scope barrier handle so that the * last thread out (not necessarily us) can release the lock. */ ptw32_mcs_node_transfer(&b->proxynode, &node); /* * Any threads that have not quite entered sem_wait below when the * multiple_post has completed will nevertheless continue through * the semaphore (barrier). */ result = (b->nInitialBarrierHeight > 1 ? sem_post_multiple (&(b->semBarrierBreeched), b->nInitialBarrierHeight - 1) : 0); } else { ptw32_mcs_lock_release(&node); /* * Use the non-cancelable version of sem_wait(). * * It is possible that all nInitialBarrierHeight-1 threads are * at this point when the last thread enters the barrier, resets * nCurrentBarrierHeight = nInitialBarrierHeight and leaves. * If pthread_barrier_destroy is called at that moment then the * barrier will be destroyed along with the semas. */ result = ptw32_semwait (&(b->semBarrierBreeched)); } if ((PTW32_INTERLOCKED_LONG)PTW32_INTERLOCKED_INCREMENT_LONG((PTW32_INTERLOCKED_LONGPTR)&b->nCurrentBarrierHeight) == (PTW32_INTERLOCKED_LONG)b->nInitialBarrierHeight) { /* * We are the last thread to cross this barrier */ ptw32_mcs_lock_release(&b->proxynode); if (0 == result) { result = PTHREAD_BARRIER_SERIAL_THREAD; } } return (result); }