This topic pertains only to applications written in C++.

Sometimes it is desirable to tell the loader where to get an object, without actually loading that object, so that the loader can retrieve it if the object is later referred to by other objects as they are being loaded. You might also want to give an object a new attribute so that the loader can find it by that attribute.

The SetObject method takes as a parameter a DMUS_OBJECTDESC structure that contains two key pieces of information:

• A pointer to the data. This can be either a file path or a pointer to a block of memory. (See Loading an Object from a File and Loading an Object from a Resource.)
• An identifier for the object when it is referred to later. This could be a GUID or a name. Later, the call to GetObject will find the stored object by using the same name or GUID. You cannot change a GUID or name that already exists in the object.
• The following code example assigns a name to an unnamed object (such as a MIDI file) in a resource:

HRESULT SetObjectFromResource(const GUID* guid, int ID,
        char* type, WCHAR* name)
{
  HRSRC hResource = NULL;
  HGLOBAL hData = NULL;
  hResource = FindResource(g_hInstance, MAKEINTRESOURCE(ID), type);
  if (hResource != NULL)
  {
    hData = LoadResource(g_hInstance, hResource); 
    if (hData != NULL)
    {
      DMUS_OBJECTDESC desc;
      if(m_pLoader && (hResource != NULL) && (hData != NULL))
      {
        ZeroMemory(&desc,sizeof(desc));
        desc.pbMemData = (BYTE*) LockResource(*hData);
        desc.llMemLength = SizeofResource(g_hInstance, (*hResource));
        desc.guidClass = (*guid);
        desc.dwSize = sizeof(desc);
        desc.dwValidData = DMUS_OBJ_CLASS | DMUS_OBJ_MEMORY;
        if (name)
        {
            wcscpy(desc.wszName, name);
            desc.dwValidData |= DMUS_OBJ_NAME;
        }
        return m_pLoader->SetObject(&desc);
      }
    }
  }
  return E_FAIL;
}

The following code could be used to assign a name to a MIDI file stored as a resource of type MIDI:

SetObjectFromResource(CLSID_DirectMusicSegment, 101,
        "MIDI", "canyon");

The object can now be loaded at any time by name.