pthread_mutex_init()函数用于创建一个互斥量,第一个参数指向互斥量的数据结构pthread_mutex_t的指针,第二个参数是定义互斥量属性的pthread_mutexattr_t结构的指针,他的默认类型是fast。类似于信号量的使用方法,pthread_mutex_lock()是对互斥量进行锁定操作,pthread_mutex_unlock()是对互斥量进行解锁操作,pthread_mutex_destroy()的作用是清除互斥量。
演示互斥量的操作方法
#include <stdio.h> #include <unistd.h> #include <pthread.h> #include <string.h> #include <stdlib.h> #include <semaphore.h> void *thread_function(void *arg); pthread_mutex_t work_mutex; //定义互斥量 #define WORK_SIZE 1024 char work_area[WORK_SIZE]; int time_to_exit=1; int main () { int res; pthread_t a_thread; //保存创建线程的返回值 void *thread_result; //结束线程的返回值 res=pthread_mutex_init(&work_mutex,NULL); //创建初始化互斥量 if(res!=0) { perror("互斥量初始化失败"); exit(EXIT_FAILURE); } res=pthread_create(&a_thread,NULL,thread_function,NULL); if(res!=0) { perror("线程创建失败"); exit(EXIT_FAILURE); } pthread_mutex_lock(&work_mutex); //锁定互斥量 //上锁 printf("请输入要传递的信息,输入end退出\n"); while(time_to_exit) { fgets(work_area,WORK_SIZE,stdin); pthread_mutex_unlock(&work_mutex); //解除互斥锁 while(time_to_exit) { pthread_mutex_lock(&work_mutex); if(work_area[0]!='\0') { pthread_mutex_unlock(&work_mutex); sleep(1); } else { break; } } } pthread_mutex_unlock(&work_mutex); printf("\n等待线程结束\n"); res=pthread_join(a_thread,&thread_result); if(res!=0) { perror("结束线程创建失败"); exit(EXIT_FAILURE); } printf("线程结束\n"); pthread_mutex_destroy(&work_mutex); exit(EXIT_SUCCESS); } void *thread_function(void *arg) { sleep(1); pthread_mutex_lock(&work_mutex); while(strncmp("end",work_area,3)!=0) { printf("收到字符%d个\n",strlen(work_area)-1); work_area[0]='\0'; pthread_mutex_unlock(&work_mutex); sleep(1); pthread_mutex_lock(&work_mutex); while(work_area[0]=='\0') { pthread_mutex_unlock(&work_mutex); sleep(1); pthread_mutex_lock(&work_mutex); } } time_to_exit=0; work_area[0]='\0'; pthread_mutex_unlock(&work_mutex); pthread_exit(0); }
文章来源: 线程中互斥锁mutex来实现同步