/* * Copyright (C) 2023 Amazon.com Inc. or its affiliates. All rights reserved. * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception */ #include #include #define MAX_NUM_THREADS 4 #define NUM_ITER 100000 int g_add_count = 0; int g_sub_count = 0; static void * thread(void *arg) { for (int i = 0; i < NUM_ITER; i++) { __atomic_fetch_add(&g_add_count, 1, __ATOMIC_SEQ_CST); __atomic_fetch_sub(&g_sub_count, 1, __ATOMIC_SEQ_CST); } return NULL; } int main(int argc, char **argv) { pthread_t tids[MAX_NUM_THREADS]; for (int i = 0; i < MAX_NUM_THREADS; i++) { if (pthread_create(&tids[i], NULL, thread, NULL) != 0) { printf("Thread creation failed\n"); } } for (int i = 0; i < MAX_NUM_THREADS; i++) { if (pthread_join(tids[i], NULL) != 0) { printf("Thread join failed\n"); } } printf("Value of counter after add update: %d (expected=%d)\n", g_add_count, MAX_NUM_THREADS * NUM_ITER); if (g_add_count != MAX_NUM_THREADS * NUM_ITER) { __builtin_trap(); } printf("Value of counter after sub update: %d (expected=%d)\n", g_sub_count, -(MAX_NUM_THREADS * NUM_ITER)); if (g_sub_count != -(MAX_NUM_THREADS * NUM_ITER)) { __builtin_trap(); } return -1; }