www.pudn.com > vxworks_networking.rar > unixClient.c

/* unixCient.c - Example code of UDP client */
 
 /* Copyright 1984-1997 Wind River Systems, Inc. */
 
 /*
 modification history
 --------------------
 01c,06nov97,mm   added copyright.
 01b,24Sep97,mm   cast arg 5 of sendto and recvfrom   
 01a,10Feb94,ms   cleaned up for VxDemo.
 */
 
 
 /***********************************************************************
  * DESCRIPTION
  *     Code to be executed by client. Writes request/message nto socket
  *     and optionally receives a reply back. Code executes on UNIX,
  *     therefore UNIX header files are included.
  *
  * 
  * EXAMPLE
  *     On the UNIX host:
  *     % unixClient 
  *
  */
 	
 
 /* Code to be executed by client. Writes request/message
  * into socket and optionally receives a reply back.
  */
 
 	
 
 /* Code executes on UNIX therefore include UNIX header files. */
 
 #include 
 #include 
 #include 
 #include 
 #include 
 #include "udpExample.h"
 #include "client.h"
 
 
 main()
 
     {
     int sFd;				/* Socket file descriptor */
     int mlen;				/* Length of message to send */
     struct request myRequest;		/* Request/Message to send to server */
     struct sockaddr_in replyAddr;	/* If expecting reply,
  					 * address of node that sent
 					 * the reply */
     char reply;				/* TRUE if want reply */
     char replyBuf[REPLY_MSG_SIZE];	/* Buffer to store reply
 					 * from server. */
     struct sockaddr_in serverSockAddr; /* Address of server */
 
     /* Size of socket address structure */
     int sockAddrSize = sizeof (struct sockaddr_in);
 
     /* Create socket */
     if ((sFd = socket (AF_INET, SOCK_DGRAM, 0)) == ERROR)
         {
 	fprintf (stderr, "Error creating socket\n");
 	return (ERROR);
 	}
 
     /* Bind not required - port number will be dynamic */
     /* Build server socket address */
     bzero (&serverSockAddr, sockAddrSize);
     serverSockAddr.sin_family = AF_INET;
     serverSockAddr.sin_port = htons (SERVER_PORT_NUM);
     serverSockAddr.sin_addr.s_addr = inet_addr (SERVER_INET_ADDR);
 
     /* Build request/message , prompting user */
     printf ("Message to send: \n");
     mlen = read (STDIN_FILENO, myRequest.message, MSG_SIZE);
     myRequest.message[mlen - 1] = '\0'; 
     printf ("Would you like a reply (Y or N): \n");
     scanf ("%c",&reply);
 
     switch (reply)
         {
 	case 'y':
 	case 'Y': myRequest.reply = TRUE;
  	    break;
 
 	default: myRequest.reply = FALSE;
             break;
 	}
 
     /* Send message/request to server */
     if (sendto (sFd, (caddr_t) &myRequest, sizeof (myRequest), 0,
                   (struct sockaddr  *) &serverSockAddr,sockAddrSize) == ERROR)
         {
 	perror ("sendto");
 	close (sFd);
 	return (ERROR);
 	}
 
     /* If expecting reply, read and print it */
     if (myRequest.reply)
         {
 	/* Should use select here. If request or reply get lost,
   	 * this code will block forever. */
 
         if (recvfrom (sFd, replyBuf, REPLY_MSG_SIZE, 0,
             (struct sockaddr  *) &replyAddr, &sockAddrSize) == ERROR)
             {
 	    perror ("recvfrom");
 	    close (sFd);
 	    return (ERROR);
 	    }
 
         printf ("MESSAGE FROM SERVER:\n%s\n", replyBuf);
         }
 
     close (sFd);
 
     }