The IAddrBook::QueryDefaultRecipOpt method returns the recipient options that have been set for a particular address type by the transport provider.
HRESULT QueryDefaultRecipOpt(
LPTSTR lpszAdrType,
ULONG ulFlags,
ULONG FAR * lpcValues,
LPSPropValue FAR * lppOptions
);
Recipient options are properties that are set by a transport provider when MAPI calls its IXPLogon::RegisterOptions method. Not all transport providers register recipient options. Recipient options are usually, but not always, specific to a particular address type.
Clients and service providers call the IAddrBook::QueryDefaultRecipOpt method to programmatically retrieve the recipient options for a particular address type. If a client must display a dialog box with these options, the client should call the IAddrBook::RecipOptions method.
Transport providers can also register message options that apply to all recipients. For more information on registering options, see Implementing Message and Recipient Options with Transport Providers.
IAddrBook::RecipOptions, IMAPISession::MessageOptions, IMAPISession::QueryDefaultMessageOpt