CBaseObject Class (Compact 2013)

3/26/2014

CBaseObject Class

This class is an abstract base class that is the basis for all component objects.

It maintains a process-wide count of active objects that can be queried from the DllCanUnloadNow entry point.

All Component Object Model (COM) objects are derived from the CUnknown class, which is derived from the CBaseObject class.

Other objects can be derived from CBaseObject to assist in the detection of memory leaks, because CBaseObject maintains the count of created objects.

The constructor requires a character-string name that describes the object being created.

This string can be displayed on the debugging screen to trace the creation of objects; the string is also displayed upon deletion of the object.

The string should be created in static storage rather than in local-function storage.

The string can be enclosed by the NAME macro, which compiles to NULL in release builds so the static strings are optimized out during compilation.

/* Typical object creation method */
HRESULT CSomeClass::CreateMyObject(void)
{
   HRESULT hr = NOERROR;
   CMyObject *pObject = new CMyObject(NAME("My filter object"),NULL,&hr);
      if (FAILED(hr)) {
         return hr;
   }
   if (pObject == NULL) {
      return E_OUTOFMEMORY;
   }
   m_pObject = pObject;
   return NOERROR;
}
/* Incorrect object creation method */
HRESULT CSomeClass::ThisMayAccessViolate(void)
{
   HRESULT hr = NOERROR;
   TCHAR MyObjectName[] = TEXT("My GP faulting object");
   CMyObject *pObject = new CMyObject(MyObjectName,NULL,&hr);
}

Member Functions

Member function	Description
CBaseObject	Constructs a CBaseObject object.
ObjectsActive	Retrieves the count of active objects.

Requirements

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

See Also

Reference

DirectShow Classes