C# Signature:

    /* converts a network address in its standard text presentation form into its numeric binary form in a sockaddr structure.  */
    [ DllImport ( "Ws2_32.dll",
              CharSet = CharSet.Unicode,
              EntryPoint = "WSAStringToAddressW" ) ]
    public static extern uint WSAStringToAddress (
                      string        AddressString,
                      ADDRESS_FAMILIES    AddressFamily,
                      IntPtr        lpProtocolInfo,
                      ref sockaddr_in6    pAddr,
                      ref int        lpAddressLength);

VB Signature:

Declare Function WSAStringToAddress Lib "ws2_32.dll" (TODO) As TODO

Parameters:

• addressStrings: A pointer to the string that contains the network address to convert.
• addressFamily: The address family of the network address
• lpProtocolInfo: The WSAPROTOCOL_INFO structure associated with the provider to be used. If this is NULL, the call is routed to the provider of the first protocol supporting the indicated AddressFamily.
• socketAddress: A pointer to a buffer that is filled with a sockaddr structure for the address string if the function succeeds.
• socketAddressSize: A pointer to the length, in bytes, of the buffer pointed to by the lpAddress parameter.

Notes:

The application must first call WSAStartup before calling WSAStringToAddress.

Sample Code:

    WSADATA data = new WSADATA();
    SockAddr sockAddr = new SockAddr();
    IntPtr pSockAddr = IntPtr.Zero;

    if (WSAStartup(0x201, ref data) == ERROR_SUCCESS)
    {
        int sockAddrSize = Marshal.SizeOf(sockAddr);

        int result = WSAStringToAddress(
        "1.2.3.4",
        System.Net.Sockets.AddressFamily.InterNetwork,
        IntPtr.Zero,
        ref sockAddr,
        ref sockAddrSize);

        WSACleanup();
    }

    if (result != ERROR_SUCCESS)
    {
         throw new Win32Exception(result);
    }

    pSockAddr = Marshal.AllocHGlobal(Marshal.SizeOf(sockAddr));
    Marshal.StructureToPtr(sockAddr, pSockAddr, true);