CAutoLock Class

This 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

Member Functions

Requirements

DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.
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Last updated on Wednesday, April 13, 2005

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