PreferredLoadFormat Example for C++ 5.0 and later

ILEADRasterIO *pRasterIO=NULL;
CoCreateInstance(CLSID_LEADRasterIO, NULL, CLSCTX_ALL,
                 IID_ILEADRasterIO, (void**)&pRasterIO);
pRasterIO->PutPreferredLoadFormat(FILE_CMP);
//....... load a file
pRasterIO->Release();