The GetCredentials method
returns a credential handle for the user identified in the USERID
parameter. If the USERID parameter contains an empty string, a credential
handle is returned for the user making the request.
A credential handle
is a token representing an identity's authorizations on the SAS Metadata
Server. Clients get and use the handle to reduce the number of authorization
requests made to the SAS Metadata Server on behalf of a user.
Every credential handle
that is returned by the GetCredentials method should be freed using
the FreeCredentials method when it is no longer needed.