CAutoLock Class (Compact 2013)

3/26/2014

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.

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	Description
M_pLock	Critical section for this lock.

Member Functions

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

Requirements

Header	dshow.h, Streams.h
Library	ole32.lib, Ole32auth.lib, Strmbase.lib, Strmiids.lib, uuid.lib

See Also

Reference

DirectShow Classes