OpenCV parallel_for check HAVE_CONCURRENCY

parallel.cpp

void cv::parallel_for_(const cv::Range& range, const cv::ParallelLoopBody& body, double nstripes)
{
#ifdef HAVE_PARALLEL_FRAMEWORK

    if(numThreads != 0)
    {
        ProxyLoopBody pbody(body, range, nstripes);
        cv::Range stripeRange = pbody.stripeRange();

#if defined HAVE_TBB

        tbb::parallel_for(tbb::blocked_range<int>(stripeRange.start, stripeRange.end), pbody);

#elif defined HAVE_CSTRIPES

        parallel(MAX(0, numThreads))
        {
            int offset = stripeRange.start;
            int len = stripeRange.end - offset;
            Range r(offset + CPX_RANGE_START(len), offset + CPX_RANGE_END(len));
            pbody(r);
            barrier();
        }

#elif defined HAVE_OPENMP

        #pragma omp parallel for schedule(dynamic)
        for (int i = stripeRange.start; i < stripeRange.end; ++i)
            pbody(Range(i, i + 1));

#elif defined HAVE_GCD

        dispatch_queue_t concurrent_queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
        dispatch_apply_f(stripeRange.end - stripeRange.start, concurrent_queue, &pbody, block_function);

#elif defined HAVE_CONCURRENCY

        if(!pplScheduler || pplScheduler->Id() == Concurrency::CurrentScheduler::Id())
        {
            Concurrency::parallel_for(stripeRange.start, stripeRange.end, pbody);
        }
        else
        {
            pplScheduler->Attach();
            Concurrency::parallel_for(stripeRange.start, stripeRange.end, pbody);
            Concurrency::CurrentScheduler::Detach();
        }

#else

#error You have hacked and compiling with unsupported parallel framework

#endif

    }
    else

#endif // HAVE_PARALLEL_FRAMEWORK
    {
        (void)nstripes;
        body(range);
    }
}