条件变量的使用

#include <pthread.h>#include <stdio.h>#include <string.h>#include <stdlib.h>pthread_mutex_t mutex; pthread_cond_t cond; int cnt = 0; void* fun1(void* argv){fprintf(stdout, "enter fun1\n");pthread_mutex_lock(&mutex);while(cnt < 10){//执行下面的语句后，mutex会被释放，可以供其他的线程使用pthread_cond_wait(&cond, &mutex);}fprintf(stdout, "cnt is %d\n", cnt);pthread_mutex_unlock(&mutex);fprintf(stdout, "leave fun1\n");}void* fun2(void* argv){fprintf(stdout, "enter fun2\n");pthread_mutex_lock(&mutex);cnt = 10; //唤醒被cond阻塞的线程pthread_cond_signal(&cond);pthread_mutex_unlock(&mutex);fprintf(stdout, "leave fun2\n");}int main(){int ret; if(( ret = pthread_mutex_init(&mutex, NULL)) != 0){fprintf(stderr, "initialize mutex error. msg:%s\n", strerror(ret));}if(( ret = pthread_cond_init(&cond, NULL)) != 0){fprintf(stderr, "initialize cond error. msg:%s\n", strerror(ret));}pthread_t p1, p2; if((ret = pthread_create(&p2, NULL, fun2, NULL))){fprintf(stderr, "create thread 2 error\n"); }if((ret = pthread_create(&p1, NULL, fun1, NULL))){fprintf(stderr, "create thread 1 error\n"); }pthread_join(p1, NULL);pthread_join(p2, NULL);return 0; }