Winsock Learning 1: the server that uses WinSock to implement socket communication.

Learn about the Winsock API and refer to the server example in the book.

The source code is as follows:

/*
* File: Server. cpp
*
*/

# Include <winsock2.h>
# Include <stdio. h>
# Include <stdlib. h>

# Define default_port 5150.
# Define default_buffer 4096.
Int iport = default_port;

Bool binterface = true;
Bool brecvonly = false;
Char szaddress [128];
// Function: Usage
// Description:
// Print usage information and exit
Void usage ()
{
Printf ("Usage: Server [-P: X] [-I: IP] [-O]/n ");
Printf ("-P: X port number to listen on/N ");
Printf ("-I: Str interface to listen on/N ");
Printf ("-O dont't echo the data back/N ");
Printf ("Camel 2004-8-29 ");
Exitprocess (1 );
}

// Function:
Void validateargs (INT argc, char ** argv)
{
Int I;
For (I = 1; I <argc; I ++)
{
If (argv [I] [0] = '-') | (argv [1] [0] = '/'))
{
Switch (tolower (argv [I] [1])
{
Case 'p ':
Iport = atoi (& argv [I] [3]);
Break;
Case 'I ':
Binterface = true;
If (strlen (argv [I])> 3)
Strcpy (szaddress, & argv [I] [3]);
Break;
Case 'O ':
Brecvonly = true;
Break;
Default:
Usage ();
Break;
}
}
}

}

//
DWORD winapi clientthread (lpvoid lpparam)
{
Socket sock = (socket) lpparam;
Char szbuff [default_buffer];
Int ret,
Nleft,
Idx;
While (1)
{
// Perform a blocking Recv () call
Ret = Recv (sock, szbuff, default_buffer, 0 );
If (ret = 0) // graceful close
Break;
Else if (ret = socket_error)
{
Printf ("Recv () failed: % d/N", wsagetlasterror ());
Break;
}
Szbuff [RET] = '/0 ';
Printf ("Recv: '% s'/N", szbuff );
//
// If we selected to echo the data back, do it
//
If (! Brecvonly)
{
Nleft = ret;
Idx = 0;
//
// Make sure we write all the data
//
While (nleft> 0)
{
Ret = Send (sock, & szbuff [idx], nleft, 0 );
If (ret = 0)
Break;
Else if (ret = socket_error)
{
Printf ("Send () failed: % d/N", wsagetlasterror ());
Break;
}
Nleft-= ret;
Idx + = ret;

}
 
}

}
Return 0;

}

Int main (INT argc, char ** argv)
{
Printf ("server. CPP/N ");
Wsadata WSD;
Socket slisten,
Sclient;
Int iaddrsize;
Handle hthread;
DWORD dwthreadid;
Struct sockaddr_in local, client;
Validateargs (argc, argv );
If (wsastartup (makeword (2, 2), & WSD )! = 0)
{
Printf ("failed to load Winsock! /N ");
Return 1;
}
//
// Create out listening socket
//
Slisten = socket (af_inet, sock_stream, ipproto_ip );
If (slisten = socket_error)
{
Printf ("socket () failed: % d/N", wsagetlasterror ());
Return 1;
}
// Select the local interface, and bind to it
//
If (binterface)
{
Local. sin_addr.s_addr = inet_addr (szaddress );
If (local. sin_addr.s_addr = inaddr_none)
Usage ();
}
Else
Local. sin_addr.s_addr = htonl (inaddr_any );
Local. sin_family = af_inet;
Local. sin_port = htons (iport );

If (BIND (slisten, (struct sockaddr *) & Local, sizeof (local) = socket_error)
{
Printf ("Bing () failed: % d/N", wsagetlasterror ());
Return 1;
}
Listen (slisten, 8 );
//
// In a continuous loop, wait for incoming clients. Once one
// Is detected, create a thread and pass the handle off to it.
//
While (1)
{
Iaddrsize = sizeof (client );
Sclient = accept (slisten, (struct sockaddr *) & client, & iaddrsize );
If (sclient = invalid_socket)
{
Printf ("accept () failed: % d/N", wsagetlasterror ());
Break;
}
Printf ("accepted client: % s: % d/N", inet_ntoa (client. sin_addr), ntohs (client. sin_port ));

Hthread = createthread (null, 0, clientthread, (lpvoid) sclient, 0, & dwthreadid );
If (hthread = NULL)
{
Printf ("createthread () failed: % d/N", getlasterror ());
Break;
}
Closehandle (hthread );

}
Closesocket (slisten );
Wsacleanup ();

Return 0;
}

//--------------------------------------------------------

When compiling in VC ++ 6.0, It is not familiar with the VC ++ compiler. Open

An error occurred while parsing the function name in the Winsock API.

...

Error lnk2001: unresolved external symbol _ inet_addr @ 4
Error lnk2001: unresolved external symbol _ htons @ 4
Error lnk2001: unresolved external symbol _ socket @ 12
...

Add ws2_32.lib to the project.

Project --> setting --> link --> Object/library modules add ws2_32.lib