What type is the return value of the NetMessageBufferSend() function? I know the microsoft thing actually lists the return values, but what are the types of those values?

Return Values
If the function succeeds, the return value is NERR_Success.

If the function fails, the return value can be one of the following error codes.

Return code Description
ERROR_ACCESS_DENIED The user does not have access to the requested information.

ERROR_INVALID_PARAMETER The specified parameter is invalid.

ERROR_NOT_SUPPORTED This network request is not supported.

NERR_NameNotFound The user name could not be found.

NERR_NetworkError A general failure occurred in the network hardware.