CODEWITHSUNDEEP
objective-cmultithreading
Boon
Boon

Reputation: 41510

In Objective-C, how to detect if multiple threads are accessing the method?

In Objective-C, we know that @synchronized can be used to define a critical section, but is there a way to know if multiple threads are accessing a method or code block?

Upvotes: 1

Views: 310

Answers (1)

trojanfoe
trojanfoe

Reputation: 122458

You could use an NSLock object (reference) and test the lock using tryLock:

@interface MyObject : NSObject
{
    NSLock *_lock;
}
...

@end

@implementation MyObject

- (id)init
{
    ...
    _lock = [[NSLock alloc] init];
    ...
}

- (BOOL)myMethod
{
    if (![_lock tryLock])
    {
        NSLog(@"Failed to acquire lock");
        return NO;
    }

    // Thread has exclusive access
    // Caution; the lock won't be automatically unlocked if this method throws an exception
    // so add some exception handling here to ensure it's always unlocked...
    @try
    {
        // Do stuff
    }
    @finally
    {
        [_lock unlock];
    }
    return YES;
}

@end

Upvotes: 1

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