Opening Socket

Hey all,

I need to open a socket in C. I am a total newbie to C-programming so I used the MSDN example and got through it, making all the steps. I want to compile the program now, but I don't understand what's going wrong.
I get these errors:

Originally Posted by Compiler

C:\Users\<snip>\Cclient>cobc -x ClientSocket.c
ClientSocket.c
ClientSocket_main.c
ClientSocket_main.obj : error LNK2005: _main already defined in ClientSocket.obj
ClientSocket_main.obj : error LNK2019: unresolved external symbol _CLIENTSOCKET referenced in function _main
ClientSocket.exe : fatal error LNK1120: 1 unresolved externals

Can anyone give me a good starting point to programming a simple socket in C?

Did you include the right headers?

Maybe you should post the code ( in code quotes please ).

Originally Posted by Sipher

Did you include the right headers?

I assume MSDN has no errors in it's code-examples...

Code:

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "10000"

int __cdecl main(int argc, char **argv) 
{
    WSADATA wsaData;
    SOCKET ConnectSocket = INVALID_SOCKET;

...etc...

Code:

int __cdecl main(int argc, char **argv)

O_o ... What are you trying to do with main?! Your compiler is right to complain! Do you want to import or export it?

Where do you use that macro _CLIENTSOCKET?

What compiler are you using?

Originally Posted by Sipher

Code:

int __cdecl main(int argc, char **argv)

O_o ... What are you trying to do with main?! Your compiler is right to complain! Do you want to import or export it?

Where do you use that macro _CLIENTSOCKET?

I got it from this example: MSDN

And never: the name of _CLIENTSOCKET changes if I change the filename of the c sourcecode. If I name it cside, the error changes to _CSIDE

EDIT: The compiler is based on MSVC

You have two files: ClientSocket.c and ClientSocket_main.c. If they both include a main() function, that's one main() too many. I don't see the word _CLIENTSOCKET anywhere, so I don't know what you've done there.

Problem solved. I was compiling it with the wrong options :/
Thanx for the quick replies!