用c++封装linux系统调用-白红宇

用c++封装linux系统调用

阅读量：6547 次

发布时间：2019-06-24

本文共 2399 字，大约阅读时间需要 7 分钟。

#include 
     
      #include 
      
       #include 
       
        #include 
        
         using namespace std;class RWLock {private :    pthread_mutex_t cnt_mutex;    pthread_cond_t rw_cond;    int rd_cnt, wr_cnt;    RWLock(const RWLock&);    RWLock& operator= (const RWLock&);public :    RWLock(): rd_cnt(0),wr_cnt(0)        {            pthread_mutex_init(&cnt_mutex, NULL);            pthread_cond_init(&rw_cond, NULL);        }    void get_shared_lock()        {            pthread_mutex_lock(&cnt_mutex);            while (wr_cnt >0)                {                    pthread_cond_wait(&rw_cond,&cnt_mutex);                }            rd_cnt++;            pthread_mutex_unlock(&cnt_mutex);        }    void release_shared_lock()        {            pthread_mutex_lock(&cnt_mutex);            rd_cnt--;            if (0 == rd_cnt)                {                    pthread_cond_signal(&rw_cond);                }            pthread_mutex_unlock(&cnt_mutex);        }    void get_exclusive_lock()        {            pthread_mutex_lock(&cnt_mutex);            while (rd_cnt+wr_cnt>0)                {                    pthread_cond_wait(&rw_cond,&cnt_mutex);                }            wr_cnt++;            pthread_mutex_unlock(&cnt_mutex);        }    void release_exclusive_lock()        {            pthread_mutex_lock(&cnt_mutex);            wr_cnt--;            pthread_cond_broadcast(&rw_cond);            pthread_mutex_unlock(&cnt_mutex);        }    ~RWLock()        {            pthread_mutex_destroy(&cnt_mutex);            pthread_cond_destroy(&rw_cond);        }};class Test{private :        RWLock lock;        static void* shared_task_handler(void* arg)        {            Test* testptr = static_cast
         
          (arg);            testptr->lock.get_shared_lock();//得到共享锁            //do the shared task here            testptr->lock.release_shared_lock();        }    static void * exclusive_task_handler(void * arg)        {            Test* testptr = static_cast
          
           (arg); testptr->lock.get_exclusive_lock(); //do the exclusive task here testptr->lock.release_exclusive_lock(); }public : typedef void* (*ThreadFunc) (void*); void start() { srand(time(NULL)); const int THREADS_NO=rand()%100; pthread_t* threads = new pthread_t[THREADS_NO]; for(int i=0; i
           
             ( expression )int i;float f = 166.71;i = static_cast
            
             (f);此时结果，i的值为166。cstdlib是C++里面的一个常用函数库， 等价于C中的
             
              。