From: Eric Hodel <drbrain@...7.net>
Date: 2005-01-24T17:36:38+09:00
Subject: Re: TCPSocket.new blocks other threads

--Apple-Mail-48--600429779
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset=US-ASCII; format=flowed

On 24 Jan 2005, at 00:05, martinus wrote:

> This is a serious problem! Try this code without an internet
> connection:
>
> Thread.new {
> sleep 1
> TCPSocket.new("xxx.nonexisting.xxx", 1234)
                ^^^^^^^^^^^^^^^^^^^^^

With Thread.abort_on_exception = true

causes:

getaddrinfo: No address associated with nodename (SocketError)

after 1 second.

So this is not a TCPSocket-specific problem, but a DNS resolver 
problem, probably due to your OS' DNS resolver library performing a 
blocking call of some kind.  There's nothing Ruby can do about this, 
unless your system provides a non-blocking DNS resolver API.

Changing it to a non-local IP address with no network connection causes:

No route to host - connect(2) (Errno::EHOSTUNREACH)

after 1 second.

Adding a network connection causes it to print . until the network 
connection times out on:

ruby 1.8.2 (2004-12-25) [powerpc-darwin7.7.0]

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
FEC2 57F1 D465 EB15 5D6E  7C11 332A 551C 796C 9F04

--Apple-Mail-48--600429779
content-type: application/pgp-signature; x-mac-type=70674453;
	name=PGP.sig
content-description: This is a digitally signed message part
content-disposition: inline; filename=PGP.sig
content-transfer-encoding: 7bit

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (Darwin)

iD8DBQFB9LONMypVHHlsnwQRAnHyAKCUg9cuWceYdP57emmeM7DvvFu0xgCdEpyq
tbvgHG74hs6wkvgrF+PbMf0=
=BCYn
-----END PGP SIGNATURE-----

--Apple-Mail-48--600429779--