ONC+ Developer's Guide

Overview of Interface Routines

RPC has multiple levels of application interface to its services. These levels provide different degrees of control balanced with different amounts of interface code to implement. In order of increasing control and complexity. This section gives a summary of the routines available at each level.

Simplified Interface Routines

The simplified interfaces are used to make remote procedure calls to routines on other machines, and specify only the type of transport to use. The routines at this level are used for most applications. Descriptions and code samples can be found in the section, " Simplified Interface ".

Table 2-1 RPC Routines--Simplified Level


Routine	Function
`rpc_reg()`	Registers a procedure as an RPC program on all transports of the specified type.
`rpc_call()`	Remote calls the specified procedure on the specified remote host.
`rpc_broadcast()`	Broadcasts a call message across all transports of the specified type.

Standard Interface Routines

The standard interfaces are divided into top level, intermediate level, expert level, and bottom level. These interfaces give a developer much greater control over communication parameters such as the transport being used, how long to wait beforeresponding to errors and retransmitting requests, and so on.

Top Level Routines

At the top level, the interface is still simple, but the program has to create a client handle before making a call or create a server handle before receiving calls. If you want the application to run on all transports, use this interface. Use of these routines and code samples can be found in "Top Level Interface".

Table 2-2 RPC Routines--Top Level


Routine	Description
`clnt_create()`	Generic client creation. The program tells `clnt_create()` where the server is located and the type of transport to use.
`clnt_create_timed()`	Similar to `clnt_create()` but lets the programmer specify the maximum time allowed for each type of transport tried during the creation attempt.
`svc_create()`	Creates server handles for all transports of the specified type. The program tells `svc_create()` which dispatch function to use.
clnt_call()	Client calls a procedure to send a request to the server.

Intermediate Level Routines

The intermediate level interface of RPC lets you control details. Programs written at these lower levels are more complicated but run more efficiently. The intermediate level enables you to specify the transport to use. Use of these routines and code samples can be found in "Intermediate Level Interface".

Table 2-3 RPC Routines--Intermediate Level


Routine	Description
`clnt_tp_create()`	Creates a client handle for the specified transport.
`clnt_tp_create_timed()`	Similar to `clnt_tp_create()` but lets the programmer specify the maximum time allowed.
`svc_tp_create()`	Creates a server handle for the specified transport.
clnt_call()	Client calls a procedure to send a request to the server.

Expert Level Routines

The expert level contains a larger set of routines with which to specify transport-related parameters. Use of these routines and code samples can be found in"Expert Level Interface".

Table 2-4 RPC Routines--Expert Level


Routine	Description
`clnt_tli_create()`	Creates a client handle for the specified transport.
`svc_tli_create()`	Creates a server handle for the specified transport.
`rpcb_set()`	Calls `rpcbind` to set a map between an RPC service and a network address.
`rpcb_unset()`	Deletes a mapping set by `rpcb_set()`.
`rpcb_getaddr()`	Calls rpcbind to get the transport addresses of specified RPC services.
`svc_reg()`	Associates the specified program and version number pair with the specified dispatch routine.
`svc_unreg()`	Deletes an association set by `svc_reg()`.
clnt_call()	Client calls a procedure to send a request to the server.

Bottom Level Routines

The bottom level contains routines used for full control of transport options. "Bottom Level Interface", describes these routines.

Table 2-5 RPC Routines--Bottom Level


Routine	Description
`clnt_dg_create()`	Creates an RPC client handle for the specified remote program, using a connectionless transport.
`svc_dg_create()`	Creates an RPC server handle, using a connectionless transport.
`clnt_vc_create()`	Creates an RPC client handle for the specified remote program, using a connection-oriented transport.
`svc_vc_create()`	Creates an RPC server handle, using a connection-oriented transport.
clnt_call()	Client calls a procedure to send a request to the server.