title: omp_set_max_active_levels() and function call
body: <p>Anyone know the scope of <code>omp_set_max_active_levels()</code>, assuming function A has a omp parallel region, and within the region, each thread of A makes a call to library function B, and within library function B there are 2 levels of omp parallelism.</p>
  
  <p>Then, if we set active omp level in function A to 3 (1 in A and 2 in B),  can that ensure that library function B's parallel region work properly?</p>