This has come up several times on the mailing list. Looking for something like this to
be provided in sync.Mutex:
func (m *Mutex) TryLock() (locked bool) {
locked = atomic.CompareAndSwapInt32(&m.state, 0, mutexLocked)
if locked && raceenabled {
raceAcquire(unsafe.Pointer(m))
}
return
}
Now you could use CompareAndSwapInt32 yourself. But it gets tricky when you need to use
Lock in one function, and TryLock in another on the same mutex.
The typical use-case is something like this:
if m.TryLock() {
// do something
} else {
// do something else
}
It's very similar to select default for channels:
select {
case <-c:
// do something
default:
// do something else
}
The difference being that with such a function you can do this with a primitive.
Other languages provide this functionality:
Java:
http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/Lock.html#tryLock()
Objective-C:
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSLock_Class/Reference/Reference.html#//apple_ref/occ/instm/NSLock/tryLock
A "LockBeforeTime" would also be useful, but I understand that's more
difficult to implement.
This has come up several times on the mailing list. Looking for something like this to be provided in sync.Mutex: func (m *Mutex) TryLock() (locked bool) { locked = atomic.CompareAndSwapInt32(&m.state, 0, mutexLocked) if locked && raceenabled { raceAcquire(unsafe.Pointer(m)) } return } Now you could use CompareAndSwapInt32 yourself. But it gets tricky when you need to use Lock in one function, and TryLock in another on the same mutex. The typical use-case is something like this: if m.TryLock() { // do something } else { // do something else } It's very similar to select default for channels: select { case <-c: // do something default: // do something else } The difference being that with such a function you can do this with a primitive. Other languages provide this functionality: Java: http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/locks/Lock.html#tryLock() Objective-C: https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSLock_Class/Reference/Reference.html#//apple_ref/occ/instm/NSLock/tryLock A "LockBeforeTime" would also be useful, but I understand that's more difficult to implement.