C / C++ / MFC

struct in_addr BIN_IPV4_ADDR_LOOPBACK = {127, 0, 0, 1}; 
//IP : when I put in my ip the code states that I'm not connected
struct in6_addr BIN_IPV6_ADDR_LOOPBACK =   {   0x0, 0x0,
                                             0x0, 0x0,
                                             0x0, 0x0,
                                             0x0, 0x0,
                                             0x0, 0x0,
                                             0x0, 0x0,
                                             0x0, 0x0,
                                             0x0, 0x1 };
#define   MAX_LOCAL_NAME_LEN               64

BOOL IsNetPresent();
void Print(TCHAR *pFormat, ...);

int _tmain (int argc, TCHAR* argv[])
{
   WSADATA WSAData;

   WSAStartup(MAKEWORD(2,2), &WSAData);
   if (IsNetPresent())
	   Print(TEXT("Network Connection IS present"));
   else
	   Print(TEXT("Network Connection is NOT present"));
   WSACleanup();
   getch();
   return 0;
}

BOOL IsNetPresent()
{
   BOOL bFoundLocalAddr = FALSE;
   char szAddrASCII[MAX_LOCAL_NAME_LEN];
   ADDRINFO AddrHints, *pAI, *pAddrInfo;

   if(gethostname(szAddrASCII, MAX_LOCAL_NAME_LEN - 1))
   {
      Print(TEXT("Error getting local host name, error = %d"), WSAGetLastError());
      return FALSE;
   }

   memset(&AddrHints, 0, sizeof(AddrHints));
   AddrHints.ai_family = PF_UNSPEC;
   AddrHints.ai_flags = AI_PASSIVE;

   if(getaddrinfo(szAddrASCII, "10", &AddrHints, &pAddrInfo))
   {
      Print(TEXT("getaddrinfo(%hs) error %d"), szAddrASCII, WSAGetLastError());
      return FALSE;
   }

   bFoundLocalAddr = TRUE;
   for(pAI = pAddrInfo; pAI != NULL && bFoundLocalAddr; pAI = pAI->ai_next)
   {
      if(pAI->ai_family == PF_INET)
      {
         if(memcmp(&(((SOCKADDR_IN *)(pAI->ai_addr))->sin_addr), &BIN_IPV4_ADDR_LOOPBACK, sizeof(BIN_IPV4_ADDR_LOOPBACK)) == 0)
            bFoundLocalAddr = FALSE;
      }
      else if(pAI->ai_family == PF_INET6)
      {
         if(memcmp(&(((SOCKADDR_IN6 *)(pAI->ai_addr))->sin6_addr), &BIN_IPV6_ADDR_LOOPBACK, sizeof(BIN_IPV6_ADDR_LOOPBACK)) == 0)
            bFoundLocalAddr = FALSE;
      }
   }

   freeaddrinfo(pAddrInfo);

   return bFoundLocalAddr;
}

void
Print(
   TCHAR *pFormat,
   ...)
{
   va_list ArgList;
   TCHAR   Buffer[256];

   va_start (ArgList, pFormat);

   (void)StringCchPrintf(Buffer, 256, pFormat, ArgList);

#ifndef UNDER_CE
   _putts(Buffer);
#else
   OutputDebugString(Buffer);
#endif

   va_end(ArgList);
}

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The only programmers that are better than C programmers are those who code in 1's and 0's.....

Programm3r
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