The lower levels of RPC

In the examples given for programming at the simplied interface, RPC takes care of almost as many details as would the rpcgen compiler. RPC does so by choosing defaults for almost everything, including the transport protocol.

This section shows how to control these details by using lower levels of the RPC library. The reader is assumed to be familiar with the Transport Level Interface (XTI).

There are several reasons for using lower levels of RPC:

• A program may need to directly control the selection of the transport protocol, which at the simplified interface level, can be done only by use of the NETPATH variable.

• A program may need to allocate and free memory while serializing or deserializing with XDR routines. There are no facilities for doing so available at the higher level. (For details, see ``An example of performing memory allocation with XDR'').

The following sections illustrate programming at the lower levels of RPC.

``The top level'' describes RPC interfaces that allow for control of transport selection by type.

``The intermediate level'' section describes those interfaces that allow a programmer to choose a specific transport.

``The expert level'' section describes routines that:

• allow program control of client and server characteristics

• provide an interface to rpcbind

Finally, the section on ``The bottom level'' describes routines that control most details of transport options.

For detailed descriptions of RPC routines, see rpc(NS).