1 files changed, 11 insertions, 0 deletions
diff --git a/src/thread/sem_trywait.c b/src/thread/sem_trywait.c
new file mode 100644
index 00000000..d0e928ef
--- /dev/null
+++ b/src/thread/sem_trywait.c
@@ -0,0 +1,11 @@
+#include <semaphore.h>
+#include "pthread_impl.h"
+
+int sem_trywait(sem_t *sem)
+{
+	int val = a_fetch_add(sem->__val, -1);
+	if (val > 0) return 0;
+	a_inc(sem->__val);
+	errno = EAGAIN;
+	return -1;
+}