vxtimeclient.c

嵌入式VxWorks开发的各种实验源代码以及相关教程

/* vxTimeClient.c - RPC client example */

#include "vxWorks.h"
#include "stdio.h"
#include "stdlib.h"
#include "rpcLib.h"
#include "rpc/rpc.h"
#include "time.h"

LOCAL CLIENT * pClient;

/*************************************************
*
* printTime - print the date and time in a human-
* readable format. 
*    For interactive use from the WindSh shell, 
* just pass 0 as the second argument ppClient.
* For programmatic use, declare a variable of
* type CLIENT *, initialize it to NULL, and
* pass the address of the variable as the ppClient
* argument. The variable will be set to a newly
* created CLIENT *, which may be reused in later
* calls to printTime by the same task. When the task
* has called printTime () for the last time, it should
* clean up its CLIENT * with a call to 
* clnt_destroy().
*/

STATUS printTime 
	(
	char * host,
	CLIENT ** ppClient
	)
	{
	char **ptr;

	if (ppClient == NULL)
		{
		pClient = NULL;
		ppClient = &pClient;
		}

	/*
	 * If *ppClient is NULL, this task has not
	 * previously called printTime, and we should
	 * initialize RPC support and create a new 
	 * client handle for it. Note: it's ok to call
	 * rpcTaskInit() more than once for the same
	 * task.
	 */

	if (*ppClient == NULL)
		{
		if (rpcTaskInit() == ERROR)
			{
			perror ("rpcTaskInit() failed");
			return (ERROR);
			}

		*ppClient = clnt_create (host, TIME_PROG,
										TIME_VERS, "tcp");
		if (*ppClient == NULL)
			{
			perror ("clnt_create failed");
			return (ERROR);
			}
		}

	 if ((ptr = print_time_1 (NULL, *ppClient))
			== NULL)
		{
		perror ("print_time_1 failed");
		clnt_destroy (*ppClient);
		*ppClient = NULL;
		return (ERROR);
		}

	printf (*ptr);

	free (*ptr);
	
	/*
	 * interactive use: destroy *ppClient.
	 * otherwise, caller is responsible.
	 */

	if (ppClient == &pClient)
		clnt_destroy (pClient);

	return (OK);
	}