IStream* pStream = NULL;
char buf[] = "hello IStream";
HGLOBAL hBlock = GlobalAlloc(PTR, sizeof(buf));
if (hBlock == NULL) // err
if (SUCCEEDED(CreateStreamOnHGlobal(hBlock, FALSE, &pStream)) {
 // Do something with pStream

 // Release
 pStream->Release();
}
// Free block
GlobalFree(hBlock);