X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fthread%2Fsem_trywait.c;h=dd8f57e36a0bd54a60a5b4c21516b9a1b6a8bba5;hb=94a0171d807dc94302d6505041fc58879c27f3bd;hp=d0e928ef67d2048f4bbf1f1214a30407d8dbe7c8;hpb=6fc5fdbdc70dd17ea8e681a361fb4dae541ee953;p=musl

diff --git a/src/thread/sem_trywait.c b/src/thread/sem_trywait.c
index d0e928ef..dd8f57e3 100644
--- a/src/thread/sem_trywait.c
+++ b/src/thread/sem_trywait.c
@@ -3,9 +3,8 @@
 
 int sem_trywait(sem_t *sem)
 {
-	int val = a_fetch_add(sem->__val, -1);
-	if (val > 0) return 0;
-	a_inc(sem->__val);
+	int val = sem->__val[0];
+	if (val>0 && a_cas(sem->__val, val, val-1)==val) return 0;
 	errno = EAGAIN;
 	return -1;
 }