C++临界区自动锁

偷懒copy了一个网上现成的自动锁，嵌入项目后调试中屡屡出问题，原类如下：

class CLock
{
public:  CLock()  {  InitializeCriticalSection(&m_cs);  }  ~CLock(){  DeleteCriticalSection(&m_cs);  }  void Lock()  {  EnterCriticalSection(&m_cs);}  void Unlock(){  LeaveCriticalSection(&m_cs);  }  
private:  CRITICAL_SECTION    m_cs;  
};class AutoLock
{
public:AutoLock()  {m_lock.Lock();}  ~AutoLock(){m_lock.Unlock();}
private:CLock   m_lock;
private:AutoLock(const AutoLock& lock);AutoLock& operator=(const AutoLock& lock);
};

调用时使用 

AutoLock auto_lock; 

测试代码：

#define THREAD_NUM 64     //最大只能64线程
int   g_nResource;DWORD WINAPI ThreadProc(LPVOID lpParam)
{{AutoLock auto_lock;printf("Thread id %d Resource Count %d\n",GetCurrentThreadId(),g_nResource);g_nResource++;}Sleep(1);return 0;
}int main(int argc, char *argv[])
{HANDLE hThreads[THREAD_NUM] = {0};for(int i = 0; i < THREAD_NUM; i++)hThreads[i] = CreateThread(NULL, 0, ThreadProc, NULL, 0, NULL);WaitForMultipleObjects(THREAD_NUM, hThreads, TRUE, INFINITE);getchar();return 0;
}

分析发现是 AutoLock auto_lock; 每次创建的CLock是私有变量，没法解决共享问题。

因此要解决，其一，将CLock调整为全局变量，但带来安全问题。其二，定义为局部静态变量。

class CLock
{
public:  CLock()  {  InitializeCriticalSection(&m_cs);  }  ~CLock(){  DeleteCriticalSection(&m_cs);  }  void Lock()  {  EnterCriticalSection(&m_cs);}  void Unlock(){  LeaveCriticalSection(&m_cs);  }  
private:  CRITICAL_SECTION    m_cs;  
};class AutoLock
{
public:AutoLock()  {m_lock.Lock();}  ~AutoLock(){m_lock.Unlock();}
private:static CLock   m_lock;//声明，全局中初始化
private:AutoLock(const AutoLock& lock);AutoLock& operator=(const AutoLock& lock);
};
CLock  AutoLock::m_lock;//初始化

再次测试，OK！

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