RE: Some code ( tcpip programing )

["Paul Robson" <probson@powerup.com.au>]

The reason is because WSAStartup returns 0 if it was successful:

from the MSDN:

Return Values
The WSAStartup function returns zero if successful. Otherwise, it returns
one of the error codes listed below.

An application cannot call WSAGetLastError to determine the error code as is
normally done in Windows Sockets is WSAStartup fails. The WS2_32.DLL will
not have been loaded in the case of a failure so the client data area where
the "last error" information is stored could not be established


--

therefore you will need to change your if statement to:
if (!WSAStartup(MAKEWORD(1, 1),&wsaData) != 0)
{
...

or alternatively do something like this (also from MSDN :)

WORD wVersionRequested;
WSADATA wsaData;
int err;

wVersionRequested = MAKEWORD( 2, 0 );

err = WSAStartup( wVersionRequested, &wsaData );
if ( err != 0 ) {
    /* Tell the user that we couldn't find a usable */
    /* WinSock DLL.                                  */
    return;
}

/* Confirm that the WinSock DLL supports 2.0.*/
/* Note that if the DLL supports versions greater    */
/* than 2.0 in addition to 2.0, it will still return */
/* 2.0 in wVersion since that is the version we      */
/* requested.                                        */

if ( LOBYTE( wsaData.wVersion ) != 2 ||
        HIBYTE( wsaData.wVersion ) != 0 ) {
    /* Tell the user that we couldn't find a usable */
    /* WinSock DLL.                                  */
    WSACleanup( );
    return;
}

/* The WinSock DLL is acceptable. Proceed. */


Paul Robson

> -----Original Message-----
> From: gameprogrammer-owner@gameprogrammer.com
> [mailto:gameprogrammer-owner@gameprogrammer.com]On Behalf Of qdlaty
> Sent: Sunday, October 03, 1999 7:36
> To: gameprogrammer@gameprogrammer.com
> Subject: Some code ( tcpip programing )
>
>
> Hello group!
>
> I've just started writing some basic multiplayer game, and I have two
> quastions about tcpip programing.
>
> 1. Why this program doesn't work? When I run it, he tells me that he cant
> init socket. Why?
>
>
> #include  <windows,.h>
>
> #include <winsock.h>
> #include <stdio.h>
>
> int server_socket;
> struct sockaddr_in s_in;
>
> void main(void)
> {
> WSAData wsaData;
> if (WSAStartup(MAKEWORD(1, 1),&wsaData) != 0)
> {
>   printf("Error while WSAStartup()");
>   return;
> }
>
> memset(&s_in,0,sizeof(s_in));
>
> s_in.sin_family = AF_INET;
> s_in.sin_addr.s_addr = INADDR_ANY;
> s_in.sin_port = htons(21);
>
> server_socket = socket(AF_INET,SOCK_STREAM,0);
>
> if(server_socket = INVALID_SOCKET)
> {
>   printf(" Could not init socket. Error %i \n",server_socket);        //
> This is where program return error
>   return;
> }
> printf("All ok");
> return;
> }
>
> I compile it under VC++ 5.0
>
> 2. Where can I find some good tuts about network programing under
> win9x/nt?
> ( links..)
>
> E-mail:      qdlaty@box43.gnet.pl
> UIN: 47212456
>
>
>
>
>
> -------------------------------------------------------------------------
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>
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We were all beginners once

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