X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fthread%2Fsem_trywait.c;h=55d90075e274a5e0a82359ffc96e6b45a279e286;hb=3f39c9b3130cd6c142d358159879b799370a6663;hp=dd8f57e36a0bd54a60a5b4c21516b9a1b6a8bba5;hpb=e983aea0aec4b77cd3eb39dabc763b08c4485395;p=musl

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;
 }