Question

Good morning, Is it possible for MapViewOfFile to return the same address twice? However, UnmapViewOfFile misbehaves when it has to unmap the same address twice. We get an Error 487 : Invalid address. Here is some pseudo code which shows how we are using MapViewOfFile and UnMapViewOfFile:

retval =    UnmapViewOfFile(TmpPrevMapPtr);            
if (retval == 0){
    DWORD lasterr = GetLastError();
    printf("UNMAP Last Error = %d ...
      }

  MapPtr = (char*)::MapViewOfFile( hMapping, FILE_MAP_WRITE | FILE_MAP_READ,0,baseoff,
mappedlength);
  if (MapPtr == 0){
    throw cException(ERR_MEMORYMAPPING,TempFileName);
  }

  Thank you.

Answer 1

After you did UnmapViewOfFile that virtual address is free to be used for other operation. So yes, the subsequent MapViewOfFile may return this address.