X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fthread%2Fsem_post.c;h=31e3293d20504a85deaebca70ded98567ba9561e;hb=246f1c811448f37a44b41cd8df8d0ef9736d95f4;hp=8f4700c3058a4735516a5ae94330fb59df004234;hpb=a113434cd68ce30642c4995b1caadcd084be6f09;p=musl

diff --git a/src/thread/sem_post.c b/src/thread/sem_post.c
index 8f4700c3..31e3293d 100644
--- a/src/thread/sem_post.c
+++ b/src/thread/sem_post.c
@@ -3,8 +3,15 @@
 
 int sem_post(sem_t *sem)
 {
-	a_inc(sem->__val);
-	if (sem->__val[1])
-		__wake(sem->__val, 1, 0);
+	int val, waiters, priv = sem->__val[2];
+	do {
+		val = sem->__val[0];
+		waiters = sem->__val[1];
+		if (val == SEM_VALUE_MAX) {
+			errno = EOVERFLOW;
+			return -1;
+		}
+	} while (a_cas(sem->__val, val, val+1+(val<0)) != val);
+	if (val<0 || waiters) __wake(sem->__val, 1, priv);
 	return 0;
 }