dispatch_after with repeat / loop

gistfile1.txt

static void dispatch_repeated_internal(dispatch_time_t firstPopTime, double intervalInSeconds, dispatch_queue_t queue, void(^work)(BOOL *stop))
{    
    __block BOOL shouldStop = NO;
    dispatch_time_t nextPopTime = dispatch_time(firstPopTime, (int64_t)(intervalInSeconds * NSEC_PER_SEC));
    dispatch_after(nextPopTime, queue, ^{
        work(&shouldStop);
        if(!shouldStop)
        {
            dispatch_repeated_internal(nextPopTime, intervalInSeconds, queue, work);
        }
    });
}

void dispatch_repeated(double intervalInSeconds, dispatch_queue_t queue, void(^work)(BOOL *stop))
{
    dispatch_time_t firstPopTime = dispatch_time(DISPATCH_TIME_NOW, intervalInSeconds * NSEC_PER_SEC);
    dispatch_repeated_internal(firstPopTime, intervalInSeconds, queue, work);
}