initial check-in, version 0.5.0

src/thread/pthread_rwlock_tryrdlock.c

@@ -0,0 +1,13 @@
+#include "pthread_impl.h"
+
+int pthread_rwlock_tryrdlock(pthread_rwlock_t *rw)
+{
+	a_inc(&rw->__readers);
+	if (rw->__wrlock) {
+		a_dec(&rw->__readers);
+		if (rw->__waiters && !rw->__readers)
+			__wake(&rw->__readers, 1, 0);
+		return EAGAIN;
+	}
+	return 0;
+}