Cookies

In Example 4-33, the last argument to rpc_gss_getcred() (here, a NULL) is a user-defined cookie, whose value on return will be whatever was specified by the server when the context was created. This cookie, a four-byte value, can be used in any way appropriate for the application -- RPC does not interpret it. For example, the cookie can be a pointer or index to a structure that represents the context initiator; instead of computing this value for every request, the server computes it at context-creation time (thus saving on request-processing time).