1 files changed, 24 insertions, 0 deletions
diff --git a/libgo/go/sync/mutex.go b/libgo/go/sync/mutex.go
index 3028552..18b2ced 100644
--- a/libgo/go/sync/mutex.go
+++ b/libgo/go/sync/mutex.go
@@ -81,6 +81,30 @@ func (m *Mutex) Lock() {
 	m.lockSlow()
 }
 
+// TryLock tries to lock m and reports whether it succeeded.
+//
+// Note that while correct uses of TryLock do exist, they are rare,
+// and use of TryLock is often a sign of a deeper problem
+// in a particular use of mutexes.
+func (m *Mutex) TryLock() bool {
+	old := m.state
+	if old&(mutexLocked|mutexStarving) != 0 {
+		return false
+	}
+
+	// There may be a goroutine waiting for the mutex, but we are
+	// running now and can try to grab the mutex before that
+	// goroutine wakes up.
+	if !atomic.CompareAndSwapInt32(&m.state, old, old|mutexLocked) {
+		return false
+	}
+
+	if race.Enabled {
+		race.Acquire(unsafe.Pointer(m))
+	}
+	return true
+}
+
 func (m *Mutex) lockSlow() {
 	var waitStartTime int64
 	starving := false