From: Martin Pirker <crf@...>
Date: 2004-10-24T03:54:11+09:00
Subject: Re: UDP socket receive question

Joel VanderWerf <vjoel@path.berkeley.edu> wrote:
> Eric Hodel wrote:
>> On Oct 22, 2004, at 9:34 PM, Joel VanderWerf wrote:
>>> Martin Pirker wrote:
>>>> Copying the minimalistic UDP receive example from the online Pickaxe I
>>>> require 'socket'
>>>> port = 12000
>>>> server = UDPSocket.open
>>>> server.bind(nil, port)
>>>              ^^^
>>> Try a hostname here? You can use the string '<any>'. I guess that 
>>> means any interface.
>> 
>> No.  nil means bind to all interfaces.  See getaddrinfo(3).
> 
> Ok, but UDPSocket#bind accepts '<any>' as well. It appears (from brief 
> groping in etx/socket/socket.c) that nil and '<any>' are synonyms. So 
> substituting one for the other will not make a difference in the problem 
> the OP was trying to fix.


but it does fix it

nil gives a "UDP localhost:12000" binding according to lsof

"<any>" and "" gives a "UDP *:12000" binding and appears to work as
expected => accepts any packet arriving from any sender at this port


question is, why I didn't find this myself?

I assumed nothing set aka nil means "don't bind to anything, accept
everything", so I just copied from the example
reading the "socket-level access" paragraph at the beginning points
one to "" as INADDR_ANY, but nowhere a word of "<any>" or a definiton
of nil ?

thanks! always nice&helpful ppl here,
Martin