/* !!!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!!! !!! Copyright (c) 2017-20, Lawrence Livermore National Security, LLC !!! and DataRaceBench project contributors. See the DataRaceBench/COPYRIGHT file for details. !!! !!! SPDX-License-Identifier: (BSD-3-Clause) !!!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!!! */ /* The explicit flush directive that provides at line:29 provides release semantics is needed * here to complete the synchronization. No data race. * */ #include #include int main(){ int x = 0, y; #pragma omp parallel num_threads(2) { int thrd = omp_get_thread_num(); if (thrd == 0) { #pragma omp critical { x = 10; } #pragma omp flush(x) #pragma omp atomic write y = 1; } else { int tmp = 0; while (tmp == 0) { #pragma omp atomic read acquire tmp = y; } #pragma omp critical { if (x!=10) printf("x = %d\n", x); } } } return 0; }