The EnumVideoCallback function is an application-defined callback procedure for the IDDVideoPortContainer::EnumVideoPorts method.
HRESULT WINAPI EnumVideoCallback(
  LPDDVIDEOPORTCAPS lpDDVideoPortCaps,  
  LPVOID lpContext                      
);
 The callback function returns DDENUMRET_OK to continue the enumeration.
The callback function returns DDENUMRET_CANCEL to stop it.
Video-port related functions cannot be called from inside the EnumVideoCallback function. Attempts to do so will fail, returning DDERR_CURRENTLYNOTAVAIL.
You can use the LPDDENUMVIDEOCALLBACK data type to declare a variable that can contain a pointer to this callback function.
  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in ddraw.h.
  Import Library: User-defined.