CAutoLock Class

The CAutoLock class holds a critical section for the scope of a block or function. The constructor locks the critical section and the destructor unlocks it. The object passed to the CAutoLock constructor must be derived from the CCritSec class. Thus, by declaring a CAutoLock object as a local variable in a function, a critical section can be locked without the danger of forgetting to unlock it in some of the code paths: the destructor ensures that upon exit from the function (or the scope of the declaration), the critical section will be unlocked. Member functions in this class are not designed for overriding.

/* Typical usage ensuring object is always unlocked correctly */

HRESULT MyFunc(IMediaSample *pSample)
{
   CAutoLock cObjectLock(m_pMyLock);

   /* Ignore samples passed when inactive */

   if (!m_bActive) {
      return NOERROR;
   }

   /* Add the sample to the pending queue */

   HRESULT hr = m_PendingList.AddTail(pSample);
   if (FAILED(hr)) {
      pSample->Release();
      return hr;
   }
   return NOERROR;
}

Protected Data Members

Name	Description
m_pLock	Critical section for this lock.

Member Functions

Name	Description
CAutoLock	Takes a pointer to a critical section object and locks it.

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CAutoLock::CAutoLock

CAutoLock Class

Takes a pointer to a critical section object and locks it.

CAutoLock(
  CCritSec * plock
  );

Parameters

plock

Pointer to a critical section object.

Return Values

No return value.

Remarks

The critical section is unlocked when the CAutoLock object is destroyed.

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