1// SPDX-License-Identifier: GPL-2.0 2#include <stdio.h> 3#include <pthread.h> 4 5pthread_mutex_t a = PTHREAD_MUTEX_INITIALIZER; 6pthread_mutex_t b = PTHREAD_MUTEX_INITIALIZER; 7pthread_barrier_t bar; 8 9void *ba_lock(void *arg) 10{ 11 int ret, i; 12 13 pthread_mutex_lock(&b); 14 15 if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD) 16 pthread_barrier_destroy(&bar); 17 18 pthread_mutex_lock(&a); 19 20 pthread_mutex_unlock(&a); 21 pthread_mutex_unlock(&b); 22} 23 24int main(void) 25{ 26 pthread_t t; 27 28 pthread_barrier_init(&bar, NULL, 2); 29 30 if (pthread_create(&t, NULL, ba_lock, NULL)) { 31 fprintf(stderr, "pthread_create() failed\n"); 32 return 1; 33 } 34 pthread_mutex_lock(&a); 35 36 if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD) 37 pthread_barrier_destroy(&bar); 38 39 pthread_mutex_lock(&b); 40 41 pthread_mutex_unlock(&b); 42 pthread_mutex_unlock(&a); 43 44 pthread_join(t, NULL); 45 46 return 0; 47} 48