Program 11-2, clientNP. The conversion is straightforward, with several small differences.
Rather than locating a server using mailslots, the user enters the IP address on the command line. If the IP address is not specified, the default address is 127.0.0.1, which indicates the current system.
Functions for sending and receiving messages, such as ReceiveMessage, are used but are not shown here.
The port number, SERVER_PORT, is defined in the header file, ClntSrvr.h.
While the code is written for Windows, there are no Windows dependencies other than the WSA calls.
/* Chapter 12. clientSK.c */
/* Single-threaded command line client. */
/* WINDOWS SOCKETS VERSION. */
/* Reads a sequence of commands to send to a server process */
/* over a socket connection. Wait for and display response. */
#define _NOEXCLUSIONS /* Required to include socket definitions. */
#include "EvryThng.h"
#include "ClntSrvr.h" /* Defines request and response records. */
/* Message functions for request and response. */
/* ReceiveResponseMessage also prints the received messages. */
static DWORD SendRequestMessage (REQUEST *, SOCKET);
static DWORD ReceiveResponseMessage (RESPONSE *, SOCKET);
struct sockaddr_in ClientSAddr; /* Clients's socket address. */
int _tmain (DWORD argc, LPTSTR argv [])
{
SOCKET ClientSock = INVALID_SOCKET;
REQUEST Request; /* See ClntSrvr.h. */
RESPONSE Response; /* See ClntSrvr.h. */
WSADATA WSStartData; /* Socket library data structure. */
BOOL Quit = FALSE;
DWORD ConVal, j;
TCHAR PromptMsg [] = _T ("\nEnter Command> ");
TCHAR Req [MAX_RQRS_LEN];
TCHAR QuitMsg [] = _T ("$Quit");
/* Request: shut down client. */
TCHAR ShutMsg [] = _T ("$ShutDownServer");
/* Stop all threads. */
CHAR DefaultIPAddr [] = "127.0.0.1"; /* Local system. */
/* Initialize the WSA library, Ver 2.0, although 1.1 will work. */
WSAStartup (MAKEWORD (2, 0), &WSStartData);
/* Connect to the server. */
/* Follow the standard client socket/connect sequence. */
ClientSock = socket (AF_INET, SOCK_STREAM, 0);
memset (&ClientSAddr, 0, sizeof (ClientSAddr));
ClientSAddr.sin_family = AF_INET;
if (argc >= 2)
ClientSAddr.sin_addr.s_addr = inet_addr (argv [1]);
else
ClientSAddr.sin_addr.s_addr = inet_addr (DefaultIPAddr);
ClientSAddr.sin_port = htons (SERVER_PORT);
/* Defined as 1070. */
connect (ClientSock,
(struct sockaddr *) &ClientSAddr, sizeof (ClientSAddr));
/* Main loop to prompt user, send request, receive response. */
while (!Quit) {
_tprintf (_T ("%s"), PromptMsg);
/* Generic input, but command to server must be ASCII. */
_fgetts (Req, MAX_RQRS_LEN-1, stdin);
for (j = 0; j <= _tcslen (Req); j++)
Request.Record [j] = Req [j];
/* Get rid of the new line at the end. */
Request.Record [strlen (Request.Record) - 1] = '\0';
if (strcmp (Request.Record, QuitMsg) == 0 ||
strcmp (Request.Record, ShutMsg) == 0) Quit = TRUE;
SendRequestMessage (&Request, ClientSock);
ReceiveResponseMessage (&Response, ClientSock);
}
shutdown (ClientSock, 2); /* Disallow sends and receives. */
closesocket (ClientSock);
WSACleanup ();
_tprintf (_T ("\n****Leaving client\n"));
return 0;
}