This API is ancient, it has been unchanged since some old version of Psion EPOC ER3 or earlier.

It works on all Symbian OS releases, at least it should.

good！

The answer why it works over TCP sooner than over UDP (i.e. without having to send a packet) is that you have to create a connection before sending any packets. And establishing a connection always results in the allocation of an IP address for your phone.

I recall that it was tricky to get the local IP address of the phone when using TCP, but not due to the complexity of the API method (it was something like RSocket::LocalAddress), but the timing. When RGenericAgent returned saying that "okay, connection is up", I still had to wait for a while until it was really up. Figuring out that "while" was tricky, when - as far as I remember, at least - it turned out that we had to wait for a special state change in the connection (used NitMan for monitoring) and after that we could get that piece of information in a jiffy.

Multiple IP addresses of a phone? Duhh, that I have never heard of. Is it in connection with multiple PDPs? Even then I can't imagine that a phone is having more than one IP address.

tOtE

this works,

   TInetAddr aAddr;
     RSocket sock;
     TBuf8<20> aIP8;
     TBuf<20> aIP;
     User::LeaveIfError(sock.Open(socketServ, KAfInet, KSockStream, KProtocolInetTcp));
     
     // Get the IAP id of the underlying interface of this RConnection
     //TUint32 iapId = 0;
     //User::LeaveIfError(conn.GetIntSetting(_L("IAP\\Id"), iapId));
     
     // Get IP information from the socket
     TSoInetInterfaceInfo ifInfo;
     TPckg<TSoInetInterfaceInfo> ifInfoPkg(ifInfo);
     TSoInetIfQuery ifQuery;
     TPckg<TSoInetIfQuery> ifQueryPkg(ifQuery);
     // To find out which interfaces are using our current IAP, we must
     // enumerate and go through all of them and make a query by name for each.
     User::LeaveIfError(sock.SetOpt(KSoInetEnumInterfaces, KSolInetIfCtrl));
     
     while(sock.GetOpt(KSoInetNextInterface, KSolInetIfCtrl, ifInfoPkg) == KErrNone) {

    ifQuery.iName = ifInfo.iName;
    TInt err = sock.GetOpt(KSoInetIfQueryByName, KSolInetIfQuery, ifQueryPkg);
       if( err == KErrNone   && ifQuery.iZone[1] == g_iapId)
         {    // IAP ID is index 1 of iZone
           // We have found an interface using the IAP we are interested in.
           //if( ifinfo.iAddress.Address() >0 )
           if (!ifInfo.iAddress.IsUnspecified() && !ifInfo.iAddress.IsLoopback() && !ifInfo.iAddress.IsLinkLocal())
           {
                
            // found a IPv4 address
            aAddr = ifInfo.iAddress;
            aAddr.ConvertToV4();
         aAddr.Output(aIP);
           
            aIP8.Copy(aIP);
              
            strncpy(out,(char*)aIP8.Ptr(),aIP8.Length());
           
           
            sock.Close();
            return err; // stop & return KErrNone
        }
      }
      else if( err !=KErrNone ) {
        sock.Close();
        return err; // return with error
    }
  } // while
  sock.Close();
  return KErrNotFound; // return with KErrNotFound


Regards,
Mateen Maldar

Ok, once you have gone through all that trouble, someone might find it useful to know following little information tidbits:


is the interface index, which might come handy with multicast join/leave operations.


is the network id (usually).


Loose this. There is no reason for it (all it does, is that if address happens to be IPv6, it gets lost). Don't cripple your applications unnecessarily for IPv6.

If you want to avoid IPv6 addresses, the test "addr.Address() > 0" is a pretty good filter. Address() returns 0 for IPv6 (but, of course it also returns 0 for "0.0.0.0" or if family is not KAfInet).