3.1.5.1 Processing Server Replies to Method Calls

Upon receiving a reply from the server in response to a method call, the client MUST validate the return code. Return codes from all method calls are HRESULTs. If the returned HRESULT is 0x00000000, indicating success, the client can assume that any output parameters are present and valid.

The client MUST release any DCOM interfaces returned by the server when the client no longer has any use for them.