Objective-C / Cocoa equivalent of C# ManualResetEvent

Question

Is there an equivalent of the .NET ManualResetEvent class available for use in Objective-C / Cocoa?

Answer 1

I'm not very familiar with ManualResetEvent, but based on the documentation, it looks like the NSCondition class might be what you are looking for.

NSCondition is by no means an exact equivalent, but it does provide similar signaling functionality. You might also want to read up on NSLock.

Answer 2

Here is a wrapper class I created which emulates ManualResetEvent using NSCondition.

@interface WaitEvent : NSObject {
    NSCondition *_condition;
    bool _signaled;
}

- (id)initSignaled:(BOOL)signaled;
- (void)waitForSignal;
- (void)signal;

@end

@implementation WaitEvent

- (id)initSignaled:(BOOL)signaled
{
    if (self = ([super init])) {
        _condition = [[NSCondition alloc] init];
        _signaled = signaled;
    }

    return self;
}

- (void)waitForSignal
{
    [_condition lock];
    while (!_signaled) {
        [_condition wait];
    }

    [_condition unlock];
}

- (void)signal
{
    [_condition lock];
    _signaled = YES;
    [_condition signal];
    [_condition unlock];
}

@end

I've done just some basic testing but I think it should get the job done with much less ceremony.