X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fthread%2Fsem_post.c;h=5c2517f23606d2b22bbf480394639f580b19b001;hb=269d193820342dc109f39909d78fb30f4c978f76;hp=8f4700c3058a4735516a5ae94330fb59df004234;hpb=a113434cd68ce30642c4995b1caadcd084be6f09;p=musl

diff --git a/src/thread/sem_post.c b/src/thread/sem_post.c
index 8f4700c3..5c2517f2 100644
--- a/src/thread/sem_post.c
+++ b/src/thread/sem_post.c
@@ -1,10 +1,21 @@
 #include <semaphore.h>
+#include <limits.h>
 #include "pthread_impl.h"
 
 int sem_post(sem_t *sem)
 {
-	a_inc(sem->__val);
-	if (sem->__val[1])
-		__wake(sem->__val, 1, 0);
+	int val, new, waiters, priv = sem->__val[2];
+	do {
+		val = sem->__val[0];
+		waiters = sem->__val[1];
+		if ((val & SEM_VALUE_MAX) == SEM_VALUE_MAX) {
+			errno = EOVERFLOW;
+			return -1;
+		}
+		new = val + 1;
+		if (waiters <= 1)
+			new &= ~0x80000000;
+	} while (a_cas(sem->__val, val, new) != val);
+	if (val<0) __wake(sem->__val, waiters>1 ? 1 : -1, priv);
 	return 0;
 }