C socket programming under windows - c

Question

Hi I'm new to socket programming and I'm trying out the following code from the tutorial of http://www.binarytides.com/winsock-socket-programming-tutorial/
I'm trying to connect to server and I'm using the IP address of google. Here is the code:
#include<stdio.h>
#include<winsock2.h>
#pragma comment(lib,"ws2_32.lib") //Winsock Library
int main(int argc , char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
printf("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
printf("Could not create socket : %d" , WSAGetLastError());
}
printf("Socket created.\n");
server.sin_addr.s_addr = inet_addr("74.125.224.72");
server.sin_family = AF_INET;
server.sin_port = htons(80);
//Connect to remote server
if (connect(s, (struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("connect error");
return 1;
}
puts("Connected");
return 0;
}
So far socket can be created but I can't connect to the server. To be more specific I always exit and have following:
The program '[2060] SocketCTest.exe: Native' has exited with code 1 (0x1).
even if I set a breakpoint before returns.

Answer 1

There's no error. I've tried on my computer and connect returned with error (WSAETIMEDOUT). I'm not sure whether there are the network settings on my computer, proxies, firewalls, and so on; or that google host is configured not to accept direct socket connections.
Anyway here's your code with some small adjustments:
#include <stdio.h>
#include <conio.h>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib") //Winsock Library
int main(int argc, char *argv[])
{
WSADATA wsa;
SOCKET s;
struct sockaddr_in server;
char c = 0;
printf("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2), &wsa) != 0)
{
printf("Failed. Error Code : %d.\nPress a key to exit...", WSAGetLastError());
c = getch();
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == INVALID_SOCKET)
{
printf("Could not create socket : %d.\n", WSAGetLastError());
WSACleanup();
c = getch();
return 1;
}
printf("Socket created. Connecting...\n");
memset(&server, 0, sizeof server);
server.sin_addr.s_addr = inet_addr("74.125.224.72");
server.sin_family = AF_INET;
server.sin_port = htons(80);
//Connect to remote server
if (connect(s, (struct sockaddr *)&server, sizeof(server)) < 0)
{
printf("Connect error:%d.\nPress a key to exit...", WSAGetLastError());
closesocket(s);
WSACleanup();
c = getch();
return 1;
}
puts("Connected.\nPress a key to exit...");
closesocket(s);
WSACleanup();
c = getch();
return 0;
}
Now if you want to see the code actually connecting i'd suggest using localhost (127.0.0.1) instead of 74.125.224.72, and the port 3389 for example (it's the Remote Desktop Server (RDP) port, if you have RDP configured and running on your computer) instead of 80; or you could let 80 if you have a web server (IIS?) running on your computer.
To get a list of server programs that run on your computer run the command:
`netstat -an | findstr LISTEN`
which would output a bunch of lines (and the ones that we care about are) in this form (here's the one corresponding to the RDP example from above):
`TCP 127.0.0.1:3389 0.0.0.0:0 LISTENING`