多线程同步|多线程同步顺序打印数字线程条件变量多线程同步顺序打印数字线程

先把条件变量函数甩出来，

//等待条件 int pthread_cond_wait(pthread_cond_t *restrict cond, pthread_mutex_t *restric mutex); 1:把调用线程放到所等待条件的线程列表上 2:对传进来已经加过锁的互斥量解锁 3:线程进入休眠状态等待被唤醒注：1、2步为原子操作//通知条件 int pthread_cond_signal(pthread_cond_t *cond); int pthread_cond_broadcast(pthread_cond_t * cond);

1:通知指定条件已经满足 2:等待线程重新锁定互斥锁 3:等待线程需要重新测试条件是否满足

【多线程同步|多线程同步顺序打印数字线程条件变量】

#include #include #include using namespace std; pthread_mutex_t g_mutex; pthread_cond_tg_cond; static int num = 0; void* thread1(void* id); void* thread2(void* id); int main(int argc,char* argv[]) { pthread_mutex_init(&g_mutex,NULL); pthread_cond_init(&g_cond,NULL); pthread_t id[2]; pthread_create(&id[0],NULL,thread1,NULL); pthread_create(&id[1],NULL,thread2,NULL); pthread_join(id[0],NULL); pthread_join(id[1],NULL); pthread_cond_destroy(&g_cond); pthread_mutex_destroy(&g_mutex); int c; while((c =getchar()) != 'c') { sleep(1); } cout<< "exit process from main func" << endl; return 0; }void* thread1(void* id) { while(1) { pthread_mutex_lock(&g_mutex); if(num % 2 == 1) { //enter wait will unlock resource and block current thread. //broadcast will active wait func pthread_cond_wait(&g_cond,&g_mutex); //end wait will lock resource } cout<< "thread 1 : " << num << endl; ++num; if(num > 10000) { pthread_cond_broadcast(&g_cond); pthread_mutex_unlock(&g_mutex); pthread_exit(0); } pthread_cond_broadcast(&g_cond); pthread_mutex_unlock(&g_mutex); } }void* thread2(void* id) { while(1) { pthread_mutex_lock(&g_mutex); if(num % 2 == 0) { pthread_cond_wait(&g_cond,&g_mutex); }if(num > 10000) { pthread_mutex_unlock(&g_mutex); pthread_exit(0); }cout<< "thread 2 : " << num << endl; ++num; pthread_cond_broadcast(&g_cond); pthread_mutex_unlock(&g_mutex); } }