Programmatically check whether my machine has internet access or not

Question

How can I programmatically check whether my machine has internet access or not using C/C++, is it just a matter of pinging an IP? How does NIC do it ? I mean something like:

I am using Windows 7.

Answer 1

If you work on Windows, just try this

#include <iostream>
#include <windows.h> 
#include <wininet.h>
using namespace std;

int main(){

if(InternetCheckConnection(L"http://www.google.com",FLAG_ICC_FORCE_CONNECTION,0))
{
        cout << "connected to internet";
}

return 0;
}