Question

Can somebody explain how I can implement semaphore in Objective-C?
I did a lot of google searching on the topic, but I haven’t found anything understandable.

Answer 1

C apis can be found in sys/semaphore.h. use these in your objc wrapper/implementation.

this basic example is the first result when ‘sem_trywait example’ is googled. it shows you how you can use these apis.

then a minimal interface would take this form:

@interface MONSemaphore : NSObject
{
    sem_t semaphore;
}

- (int)close;
- (int)destroy;

/* .. and the rest of the interface you wrap and make public here .. */

@end

but it’s likely that you will also want the object to abstract the init and destruct routines from the client.