我已经解决了这一问题，方法是打开一个嵌套的并行区域来查询所有线程:

I've solved it, by opening a nested parallel region to query all threads:

int get_nested_num_threads(){
  int threads=1;

#pragma omp parallel shared(threads)
  {
  #pragma omp single
    {
      threads = omp_get_num_threads();

      #pragma omp parallel shared(threads)
      {
        #pragma omp single
        {
          threads *= omp_get_num_threads();
        }
      }
    }
  }

  return threads;
}

据我所知，在这种情况下，您无需在C中使用firstprivate和lastprivate.但是您必须在Fortran中做到这一点.

As far as I know, you do not need to use firstprivate and lastprivate in C for this case. But you have to do it in Fortran.