多线程编程-监控线程.doc

多线程编程-监控线程1、监控线程概述12、需求13、示例14、相关文献91、监控线程概述不死线程常见于进程中的关键线程，即进程内其它线程的正常运行依赖于该线程，比如在网络编程中，负责与其它模块通信的socket线程等。如何保证关键线程始终运行，常用的方法有实现监控线程，当检测到某线程退出时，采取相应的动作，如：重启线程、重启进程、或重启整个系统。本文主要结合前面的基础，讨论如何实现监控线程、重启线程，达到不死的传说。2、需求（1） 利用多线程实现对两个线程（线程1、线程2）的监控，保证线程不死；（2） 利用信号量实现线程1、线程2的同步：先启动线程1，再启动线程2。3、示例/* * 作者: Jeffrey.zhu * 功能: 线程监控示例 * 日期: 2010年6月 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */ #include #include #include #include #include #include #include /* 线程触发标志 */enum PTHREAD_ID_NONE = -1, /* 未知状态 */ PTHREAD_ID_INIT = 0, /* 初始状态触发 */ PTHREAD_ID1 = 1, /* 线程1触发 */ PTHREAD_ID2 = 2, /* 线程2触发 */;enum PTHREAD_FLAG_ON = 1, /* 标志打开 */ PTHREAD_FLAG_OFF = 0, /* 标志关闭 */;/* 返回结果 */enum ERROR = -1, /* 失败 */ OK = 0, /* 成功 */;static int start_pthread_flag = PTHREAD_ID_INIT; /* 触发线程标志 */static int pthread1_exit_flag = PTHREAD_FLAG_ON; /* pthread1退出标志 */static int pthread2_exit_flag = PTHREAD_FLAG_ON; /* pthread2退出标志 */* 线程属性及ID */static pthread_attr_t pthreads_attr; static pthread_t tmp_id = PTHREAD_ID_INIT; static pthread_t pthread1_id = PTHREAD_ID_INIT; static pthread_t pthread2_id = PTHREAD_ID_INIT;/*快速锁，对应于上文的本地全局变量 */static pthread_mutex_t start_pthread_flag_mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_mutex_t pthread1_id_mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_mutex_t pthread2_id_mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_mutex_t pthread1_exit_flag_mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_mutex_t pthread2_exit_flag_mutex = PTHREAD_MUTEX_INITIALIZER;static int lock_var;static time_t end_time;static sem_t sem2;/* 接口声明 */static void pthread1(void *arg);static void pthread2(void *arg);static void pthread1_exit(void);static void pthread2_exit(void); static int pthreads_init(void);static void pthreads_deinit(void);/* * 作者: Jeffrey.zhu * 功能: 主线程为监控线程 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */int main(int argc, char *argv) int res; end_time = time(NULL) + 30; /* 进程运行时间：30s */ res = sem_init(&sem2, 0, 0); if (0 != res) perror(sem_init); while (time(NULL) end_time) /* 启动pthread1子线程 */ if (pthread1_exit_flag = PTHREAD_FLAG_ON) /* 判断触发者 */ if (PTHREAD_ID_INIT = start_pthread_flag) | (PTHREAD_ID1 = start_pthread_flag) pthreads_deinit(); /* 首次先deinit */ res = pthreads_init(); while (ERROR = res) /* 确保初始化成功 */ fprintf(stderr, pthread init failure, reinitn); pthreads_deinit(); res = pthreads_init(); pthread_mutex_lock(&pthread2_exit_flag_mutex); pthread2_exit_flag = PTHREAD_FLAG_ON; pthread_mutex_unlock(&pthread2_exit_flag_mutex); else start_pthread_flag = PTHREAD_ID_NONE; if (1 = pthread_equal(pthread1_id, tmp_id) /* 创建线程 */ res = pthread_create(&pthread1_id, &pthreads_attr, (void *)pthread1, NULL); if (0 != res) fprintf(stderr, Create pthread1 error:%s, reinitn, strerror(errno); if (0 = pthread_equal(pthread1_id, tmp_id) pthread_cancel(pthread1_id); pthread_mutex_lock(&pthread1_id_mutex); pthread1_id = PTHREAD_ID_INIT; pthread_mutex_unlock(&pthread1_id_mutex); pthread_mutex_lock(&pthread1_exit_flag_mutex); pthread1_exit_flag = PTHREAD_FLAG_ON; pthread_mutex_unlock(&pthread1_exit_flag_mutex); else pthread_mutex_lock(&pthread1_exit_flag_mutex); pthread1_exit_flag = PTHREAD_FLAG_OFF; pthread_mutex_unlock(&pthread1_exit_flag_mutex); /* 启动pthread2子线程 */ if (pthread2_exit_flag = PTHREAD_FLAG_ON) if (PTHREAD_ID2 = start_pthread_flag) pthreads_deinit(); res = pthreads_init(); while (ERROR = res) fprintf(stderr, pthreads init failure, reinitn); pthreads_deinit(); res = pthreads_init(); pthread_mutex_lock(&pthread1_exit_flag_mutex); pthread1_exit_flag = PTHREAD_FLAG_ON; pthread_mutex_unlock(&pthread1_exit_flag_mutex); else start_pthread_flag = PTHREAD_ID_NONE; if (1 = pthread_equal(pthread2_id, tmp_id) res = pthread_create(&pthread2_id, &pthreads_attr, (void *)pthread2, NULL); if (0 != res) fprintf(stderr, Create pthread pthread2 error:%s, reinitn, strerror(errno); if (0 = pthread_equal(pthread2_id, tmp_id) pthread_cancel(pthread2_id); pthread_mutex_lock(&pthread2_id_mutex); pthread2_id = PTHREAD_ID_INIT; pthread_mutex_unlock(&pthread2_id_mutex); else pthread_mutex_lock(&pthread2_exit_flag_mutex); pthread2_exit_flag = PTHREAD_FLAG_ON; pthread_mutex_unlock(&pthread2_exit_flag_mutex); /* end of if (0 != res) */ pthread_mutex_lock(&pthread2_exit_flag_mutex); pthread2_exit_flag = PTHREAD_FLAG_OFF; pthread_mutex_unlock(&pthread2_exit_flag_mutex); /* 监控周期 */ sleep(1); pthreads_deinit(); return 0;/* * 作者: Jeffrey.zhu * 功能: 线程函数1, 唤醒线程函数2，并自行退出 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */void pthread1(void *arg) int i; while (time(NULL) end_time) for (i=0; i2; i+) lock_var+; /* lock_var为全局变量，被两个线程共享，即锁定值 */ printf(pthread1:lock_var = %dn,lock_var); sem_post(&sem2); /* 对信号量2进行V操作，加1唤醒线程2 */ sleep(2); pthread1_exit(); /* * 作者: Jeffrey.zhu * 功能: 线程函数2, 若锁定值大于10，则自行退出 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */void pthread2(void *arg) int ret; while (time(NULL) 10) pthread2_exit(); sleep(2); /* * 作者: Jeffrey.zhu * 功能: pthread1线程退出函数 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */static void pthread1_exit(void) pthread_mutex_lock(&pthread1_exit_flag_mutex); pthread1_exit_flag = PTHREAD_FLAG_ON; pthread_mutex_unlock(&pthread1_exit_flag_mutex); /* kill掉pthread2线程，防止start_pthread_flag判断之前的竞争 */ if (0 = pthread_equal(pthread2_id, tmp_id) pthread_cancel(pthread2_id); pthread_mutex_lock(&pthread2_id_mutex); pthread2_id = PTHREAD_ID_INIT; pthread_mutex_unlock(&pthread2_id_mutex); pthread_mutex_lock(&start_pthread_flag_mutex); start_pthread_flag = PTHREAD_ID1; pthread_mutex_unlock(&start_pthread_flag_mutex); pthread_mutex_lock(&pthread1_id_mutex); pthread1_id = PTHREAD_ID_INIT; pthread_mutex_unlock(&pthread1_id_mutex); printf(pthread1 is exit!n); pthread_exit(NULL);/* * 作者: Jeffrey.zhu * 功能: pthread2线程退出函数 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */static void pthread2_exit(void) pthread_mutex_lock(&pthread2_exit_flag_mutex); pthread2_exit_flag = PTHREAD_FLAG_ON; pthread_mutex_unlock(&pthread2_exit_flag_mutex); /* kill掉pthread1线程 */ if (0 = pthread_equal(pthread1_id, tmp_id) pthread_cancel(pthread2_id); pthread_mutex_lock(&pthread1_id_mutex); pthread1_id = PTHREAD_ID_INIT; pthread_mutex_unlock(&pthread1_id_mutex); pthread_mutex_lock(&start_pthread_flag_mutex); start_pthread_flag = PTHREAD_ID2; pthread_mutex_unlock(&start_pthread_flag_mutex); pthread_mutex_lock(&pthread1_id_mutex); pthread1_id = PTHREAD_ID_INIT; pthread_mutex_unlock(&pthread1_id_mutex); printf(pthread2 is exit!n); pthread_exit(NULL);/* * 作者: Jeffrey.zhu * 功能: 初始化函数 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */static int pthreads_init(void) int opt = 1; int res; /* 互斥处理 */ res = pthread_mutex_init(&start_pthread_flag_mutex, NULL); if (0 != res) printf(pthreads_init():MUTEX INIT ERROR, reinitn); return ERROR; res = pthread_mutex_init(&pthread1_id_mutex, NULL); if (0 != res) printf(pthreads_init():MUTEX INIT ERROR, reinitn); return ERROR; res = pthread_mutex_init(&pthread2_id_mutex, NULL); if (0 != res) printf(pthreads_init():MUTEX INIT ERROR, reinitn); return ERROR; res = pthread_mutex_init(&pthread1_exit_flag_mutex, NULL); if (0 != res) printf(pthreads_init():MUTEX INIT ERROR, reinitn); return ERROR; res = pthread_mutex_init(&pthread2_exit_flag_mutex, NULL); if (0 != res) printf(pthreads_init():MUTEX INIT ERROR, reinitn); return ERROR; /* 线程属性处理 */ res = pthread_attr_init(&pthreads_attr); if (0 != res) printf(pthread_attr_init():PTHREAD ATTR INIT ERROR, reinitn); return ERROR; res = pthread_attr_setdetachstate(&pthreads_attr, PTHREAD_CREATE_DETACHED); if (0 != res) printf(pthread_attr_setdetachstate():PTHREAD ATTR SET ERROR, reinitn); return ERROR; return OK;/* * 作者: Jeffrey.zhu * 功能: 资源释放函数 * 联系方式: 墨客论文网: * CSDN博客：/gueter/ */static void pthreads_deinit(void) pthread_attr_destroy(&pthreads_attr); pthread_mutex_destroy(&start_pthread_flag_mutex); pthread_mutex_destroy(&pthread1_id_mutex); pthread_mutex_destroy(&pthread2_id_mutex); pthread_mutex_destroy(&pthread1_exit_flag_mutex); pthread_mutex_destroy(&pthread2_exit_flag_mutex);4、相关文献1、基于信号量的Linux多线程同步研究 中文摘要：信号量是进程或线程之间相互通讯的手段之一。有效地使用可以在多线程之间实现同步和互斥，以保证程序的正确的运行。在对线程的数据结构和相关的10个函数分析的基础上，以一个具体的例子给出如何使用信号量机制实现多线程之间的同步。摘自墨客论文网：/view/207