| // RUN: %libomp-cxx-compile-and-run |
| |
| #include <omp.h> |
| |
| #include <algorithm> |
| #include <cassert> |
| #include <chrono> |
| #include <thread> |
| #include <vector> |
| |
| void dummy_root() { |
| // omp_get_max_threads() will do middle initialization |
| int nthreads = omp_get_max_threads(); |
| std::this_thread::sleep_for(std::chrono::milliseconds(1000)); |
| } |
| |
| int main(int argc, char *argv[]) { |
| const int N = std::min(std::max(std::max(32, 4 * omp_get_max_threads()), |
| 4 * omp_get_num_procs()), |
| std::numeric_limits<int>::max()); |
| |
| std::vector<int> data(N); |
| |
| // Create a new thread to initialize the OpenMP RTL. The new thread will not |
| // be taken as the "initial thread". |
| std::thread root(dummy_root); |
| |
| #pragma omp parallel for num_threads(N) |
| for (unsigned i = 0; i < N; ++i) { |
| data[i] = i; |
| } |
| |
| #pragma omp parallel for num_threads(N + 1) |
| for (unsigned i = 0; i < N; ++i) { |
| data[i] += i; |
| } |
| |
| for (unsigned i = 0; i < N; ++i) { |
| assert(data[i] == 2 * i); |
| } |
| |
| root.join(); |
| |
| return 0; |
| } |