Simplified Interface

The simplified interface is the level to use if you do not require the use of any other RPC routines. This level also limits control of the underlying communications mechanisms. You can rapidly develop a program at this level, and the development is directly supported by the rpcgen compiler. For most applications, rpcgen and its facilities are sufficient.

Some RPC services are not available as C functions, but they are available as RPC programs. The simplified interface library routines provide direct access to the RPC facilities for programs that do not require fine levels of control. Routines such as rusers() are in the RPC services library librpcsvc. The following code example is a program that displays the number of users on a remote host. It calls the RPC library routine rusers().

#include <rpc/rpc.h>

#include <rpcsvc/rusers.h>
#include <stdio.h>
 
/*
 * a program that calls the
 * rusers() service
 */
 
main(argc, argv)
	int argc;
	char **argv;
{
	int num;
 
	if (argc != 2) {
		fprintf(stderr, "usage: %s hostname\n", argv[0]);
		exit(1);
	}
	if ((num = rnusers(argv[1])) < 0) {
		fprintf(stderr, "error: rusers\n");
		exit(1);
	}
	fprintf(stderr, "%d users on %s\n", num, argv[1] );
	exit(0);
}

Compile the program in Example 4–1 by typing:

cc program.c -lrpcsvc -lnsl