【MFC】CSingleLock的使用

转载文章：CSingleLock的使用

// 先看看其代码:
// 声明
class CSingleLock
{
　　// Constructors
　　public:
　　CSingleLock(CSyncObject* pObject, BOOL bInitialLock = FALSE);

　　// Operations
　　public:
　　BOOL Lock(DWORD dwTimeOut = INFINITE);
　　BOOL Unlock();
　　BOOL Unlock(LONG lCount, LPLONG lPrevCount = NULL);
　　BOOL IsLocked();

　　// Implementation
　　public:
　　~CSingleLock();

　　protected:
　　CSyncObject* m_pObject;
　　HANDLE m_hObject;
　　BOOL    m_bAcquired;
};

// 实现
CSingleLock::CSingleLock(CSyncObject* pObject, BOOL bInitialLock)
{
　　ASSERT(pObject != NULL);
　　ASSERT(pObject->IsKindOf(RUNTIME_CLASS(CSyncObject)));

　　m_pObject = pObject;
　　m_hObject = pObject->m_hObject;
　　m_bAcquired = FALSE;

　　if (bInitialLock)
　　 Lock();
}

BOOL CSingleLock::Lock(DWORD dwTimeOut /* = INFINITE */)
{
　　ASSERT(m_pObject != NULL || m_hObject != NULL);
　　ASSERT(!m_bAcquired);

　　m_bAcquired = m_pObject->Lock(dwTimeOut);
　　return m_bAcquired;
}

BOOL CSingleLock::Unlock()
{
　　ASSERT(m_pObject != NULL);
　　if (m_bAcquired)
　　 m_bAcquired = !m_pObject->Unlock();

　　// successfully unlocking means it isn't acquired
　　return !m_bAcquired;
}

BOOL CSingleLock::Unlock(LONG lCount, LPLONG lpPrevCount /* = NULL */)
{
　　ASSERT(m_pObject != NULL);
　　if (m_bAcquired)
　　 m_bAcquired = !m_pObject->Unlock(lCount, lpPrevCount);

　　// successfully unlocking means it isn't acquired
　　return !m_bAcquired;
}

BOOL CSingleLock::IsLocked()
{ 
　　return m_bAcquired; 
}

CSingleLock::~CSingleLock()
{
　　Unlock(); 
}

综上得CSingleLock之使用:

• CSingleLock在函数内使用，当函数返回时将释放CSingleLock对象，同时进行解锁
• CSingleLock对象在栈上定义，构造时，Lock；CSingleLock的析构函数会自动调用同步对象的Unlock。
• CSingleLock就是为了使用方便才定义的，你作为成员变量失去他本来的意义了