diff options
Diffstat (limited to 'src/thread/sem_trywait.c')
| -rw-r--r-- | src/thread/sem_trywait.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/thread/sem_trywait.c b/src/thread/sem_trywait.c index dd8f57e3..55d90075 100644 --- a/src/thread/sem_trywait.c +++ b/src/thread/sem_trywait.c @@ -4,7 +4,10 @@ int sem_trywait(sem_t *sem) { int val = sem->__val[0]; - if (val>0 && a_cas(sem->__val, val, val-1)==val) return 0; + if (val>0) { + int new = val-1-(val==1 && sem->__val[1]); + if (a_cas(sem->__val, val, new)==val) return 0; + } errno = EAGAIN; return -1; } |