iOS CGD dispatch_group_t 等待

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_group_t group = dispatch_group_create();

    dispatch_group_async(group, queue, ^{
        for (int i =0; i<100; i++)
        {
            NSLog(@"i------:%d",i);
        }
    });
    
    dispatch_group_async(group, queue, ^{
        for (int i =0; i<100; i++) {
            NSLog(@"j======:%d",i);
        }

    });

    dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
    dispatch_release(group);
    

    NSLog(@"dspath_group_async");