线程同步
多个线程按照规定的顺序来执行，即为线程同步。
threadSync1.c
#include#include #include pthread_mutex_t mutex;int task = 0;void *thread0();void *thread1();void main(){ //创建互斥锁 pthread_mutex_init(&mutex, NULL); //创建子线程 pthread_t thread[2]; pthread_create(&thread[0], NULL, thread0, NULL); pthread_create(&thread[1], NULL, thread1, NULL); //等待子线程 pthread_join(thread[0], NULL); pthread_join(thread[1], NULL);}void *thread0(){ //处理任务 int i; for(i = 0; i < 10; i++){ //获取互斥锁 pthread_mutex_lock(&mutex); //处理任务 task++; printf("thread0 task:%d\n", task); //释放互斥锁 pthread_mutex_unlock(&mutex); //睡眠等待 sleep(1); } //退出线程 pthread_exit(NULL);}void *thread1(){ //获取互斥锁 pthread_mutex_lock(&mutex); //查看任务 while(task != 10){ //释放互斥锁 pthread_mutex_unlock(&mutex); //睡眠等待 sleep(1); //获取互斥锁 pthread_mutex_lock(&mutex); } //处理任务 task++; printf("thread1 task:%d\n", task); //释放互斥锁 pthread_mutex_unlock(&mutex); //退出线程 pthread_exit(NULL);}
threadSync2.c
#include#include #include pthread_mutex_t mutex; //互斥锁pthread_cond_t cond = PTHREAD_COND_INITIALIZER; //条件变量int task = 0;void *thread0();void *thread1();void main(){ //创建互斥锁 pthread_mutex_init(&mutex, NULL); //创建子线程 pthread_t thread[2]; pthread_create(&thread[0], NULL, thread0, NULL); pthread_create(&thread[1], NULL, thread1, NULL); //等待子线程 pthread_join(thread[0], NULL); pthread_join(thread[1], NULL);}void *thread0(){ //处理任务 int i; for(i = 0; i < 10; i++){ //获取互斥锁 pthread_mutex_lock(&mutex); //处理任务 task++; printf("thread0 task:%d\n", task); //释放互斥锁 pthread_mutex_unlock(&mutex); //睡眠等待 sleep(1); } //条件通知 pthread_cond_signal(&cond); //退出线程 pthread_exit(NULL);}void *thread1(){ //获取互斥锁 pthread_mutex_lock(&mutex); //条件等待 if(task != 10){ pthread_cond_wait(&cond, &mutex); //条件等待时会自动解锁，然后睡眠等待，获得条件通知再自动加锁 } //处理任务 task++; printf("thread1 task:%d\n", task); //释放互斥锁 pthread_mutex_unlock(&mutex); //退出线程 pthread_exit(NULL);}