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int pthread_mutex_init (pthread_mutex_t *__mutex, __const pthread_mutexattr_t *__mutexattr) ：初始化互斥锁，成功返回0
参数1：要初始化的互斥锁
参数2：定义要初始化的互斥锁属性，NULL表默认
宏 PTHREAD_MUTEX_INITIALIZER 初始化静态分配互斥锁 ？？这个语法是什么原理？？？
#define PTHREAD_MUTEX_INITIALIZER {{0,}}
初始化代码如下：
pthread_mutex_t mp = PTHREAD_MUTEX_INITIALIZER;
int pthread_mutex_destroy (pthread_mutex_t * __mutex) ：销毁互斥锁，成功返回0
int pthread_mutex_lock (pthread_mutex_t *__mutex) ：以阻塞方式申请互斥锁
int pthread_mutex_trylock (pthread_mutex_t *__mutex) ：以非阻塞方式申请互斥锁
int pthread_mutex_unlock (pthread_mutex_t *__mutex) ：释放互斥锁
例子：实现读写线程，读时不写，写时不读（我说不清楚下面的代码好不好，因为代码里面循环测试锁，跟我想象的不同，而且是写一句，读一句的。我觉得应该是可以任意写，读按顺序读）
#include<stdio.h> #include<unistd.h> #include<stdlib.h> #include<pthread.h> #include<semaphore.h> #include<string.h> void *thread_function (void *arg); //全局互斥锁对象 pthread_mutex_t work_mutex; #define WORK_SIZE 1024 //全局共享数据区 char work_area[WORK_SIZE]; int time_to_exit = 0; int main(int argc, char *argv[]) { int res; pthread_t a_thread; void *thread_result; //初始化互斥锁 res = pthread_mutex_init(&work_mutex, NULL); if(res != 0) { printf("Mutex initialization failed"); exit(EXIT_FAILURE); } //创建新线程 res = pthread_create(&a_thread, NULL, thread_function, NULL); if(res != 0) { printf("Thread creation failed"); exit(EXIT_FAILURE); } //接收输入前，给互斥锁上锁 pthread_mutex_lock(&work_mutex); printf("Input some text. Enter ‘end‘ to finish\n"); while(!time_to_exit) { fgets(work_area, WORK_SIZE, stdin); //解锁 pthread_mutex_unlock(&work_mutex); while(1) { //上锁 pthread_mutex_lock(&work_mutex); if(work_area[0] != ‘\0‘) //检测数据是否读出 { pthread_mutex_unlock(&work_mutex); //如果没有输出，解锁 sleep(1); } else { break; } } } pthread_mutex_unlock(&work_mutex); //解锁 printf("\nWaiting for thread to finish...\n"); res = pthread_join(a_thread, &thread_result); if(res != 0) { printf("Thread join failed"); exit(EXIT_FAILURE); } printf("Thread joined\n"); pthread_mutex_destroy(&work_mutex); exit(EXIT_SUCCESS); } void *thread_function(void *arg) { sleep(1); //上锁，抢占资源 pthread_mutex_lock(&work_mutex); while(strncmp("end", work_area, 3) != 0) { printf("You input %d characters\n", strlen(work_area)); printf("the characters is %s", work_area); 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 = 1; work_area[0] = ‘\0‘; pthread_mutex_unlock(&work_mutex); pthread_exit(0); }
【linux高级程序设计】（第十二章）Linux多线程编程 2
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原文地址：http://www.cnblogs.com/dplearning/p/4690241.html
