From: Sean O'Halpin <sean.ohalpin@...>
Date: 2009-02-03T08:59:56+09:00
Subject: Re: Socket: Getting EADDRNOTAVAIL in bind method

On Mon, Feb 2, 2009 at 9:50 PM, Anukul Singhal <anukul.singhal@gmail.com> wrote:
> Hi,
>
> I am new to Socket programming in ruby and want to connect to a device.
> I am able to make a connection using the following code but failing in
> the bind method. Here's the snippet:
>
>     require 'socket'
>     include Socket::Constants
>
>     socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
>     puts socket.inspect  (returns #<Socket:0x2b85694>)
>
>     sockaddr = Socket.pack_sockaddr_in(5555,'114.23.42.42')
>     puts sockaddr.inspect (returns
> "\002\000\025\263\217[\"\315\000\000\000\000\000\000\000\000")
>
>     bound = socket.bind(sockaddr)
>     puts bound.inspect
>
> In the last method bind, getting the following error:
>
> Test.rb:50:in `bind': The requested address is not valid in its context.
> - bind(2) (Errno::EADDRNOTAVAIL)
>
> I think I might be missing something elementary here. If anyone can
> please help with it, would be really grateful.
>
> Thanks,
> Anukul

I don't think it's you - the docs on socket programming are a little
frustrating. The examples in the rubydocs don't work out of the box on
my Mac for instance.

You could try this:

require 'ipaddr'

sockaddr = Socket.pack_sockaddr_in( 5555, IPAddr.new('114.23.42.42').to_i)

You might also want:

socket.setsockopt( Socket::SOL_SOCKET, Socket::SO_REUSEADDR, true )

There's a very good tutorial on socket programming in Ruby at
http://www.scribd.com/doc/3499561/Sockets-Programming-in-Ruby.

HTH

Regards,
Sean