CODEWITHSUNDEEP
c++network-programmingcross-platformbyteip-address
Safari
Safari

Reputation: 11935

Get my IP address and convert it into bytes using C++

What is the best way to get your IP address and then convert it into bytes using C++? I need something cross-platform. I found a lot but I do not know what is the best technique.

Upvotes: 0

Views: 919

Answers (4)

Ralf
Ralf

Reputation: 9573

As Ben stated, you could use a non-standard library that has implementations for many OSs. By no means is boost the silver bullet, but the boost asio library is a really useful, well-designed, portable networking library with implementations for many operating systems. Specifically asio provides the ip::host_name method.

Upvotes: 1

rushman
rushman

Reputation: 562

Two methods you can use to convert an IP to a string are inet_ntoa (IPv4 only) or getnameinfo with the flag NI_NUMERICHOST (IPv4 and IPv6).

Upvotes: 0

bilash.saha
bilash.saha

Reputation: 7296

You can use gethostname followed by gethostbyname to get your local interface internal IP.

You can try this code:

struct IPv4
{
  unsigned char b1, b2, b3, b4;
};

bool getMyIP(IPv4 & myIP)
{
  char szBuffer[1024];

  #ifdef WIN32
  WSADATA wsaData;
  WORD wVersionRequested = MAKEWORD(2, 0);
  if(::WSAStartup(wVersionRequested, &wsaData) != 0)
    return false;
  #endif


  if(gethostname(szBuffer, sizeof(szBuffer)) == SOCKET_ERROR)
  {
    #ifdef WIN32
    WSACleanup();
    #endif
    return false;
  }

  struct hostent *host = gethostbyname(szBuffer);
  if(host == NULL)
  {
    #ifdef WIN32
    WSACleanup();
    #endif
    return false;
  }

  //Obtain the computer's IP
  myIP.b1 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b1;
  myIP.b2 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b2;
  myIP.b3 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b3;
  myIP.b4 = ((struct in_addr *)(host->h_addr))->S_un.S_un_b.s_b4;

  #ifdef WIN32
  WSACleanup();
  #endif
  return true;
}

Use htonl, htons, ntohl, ntohs functions to convert between network and local byte orders.

Upvotes: 4

Ben Voigt
Ben Voigt

Reputation: 283614

There is no standard way to do this in C++, because C++ also runs on systems which have no network.

Each operating system has a different way to query local interface addresses. The most "portable" thing you can hope to find is a library that provides a single consistent interface with underlying implementations corresponding to all major operating systems.

Upvotes: 1

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