From: darren kirby <bulliver@...>
Date: 2006-06-04T01:35:40+09:00
Subject: Re: Exceptions inside loops...

--nextPart1873791.A1dPdozLbS
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline

quoth the Dave Burt:
> darren kirby wrote:
> > begin telnetPorts.each do |port|
> >    puts "Port " + port.to_s + ":"
> >    t =3D TCPSocket.new(host,port)
> >    banner =3D t.gets
> >    t.close
> > end
> >
> > rescue SystemCallError
> >    puts "Unable to connect to port: " + $!
> > end
>
> I see the question has been answered; let me just explain a little furthe=
r.
>
> Here's the code you posted above with standard indentation:
>
> begin
>   telnetPorts.each do |port|
>     puts "Port " + port.to_s + ":"
>     t =3D TCPSocket.new(host,port)
>     banner =3D t.gets
>     t.close
>   end
> rescue SystemCallError
>    puts "Unable to connect to port: " + $!
> end
>
> The first "end" closes the do..end block given to the each method. The
> second end closes the begin..end block. The rescue clause applies to the
> begin..end block.
>
> (Obviously) begin..end is used to introduce a new scope, often for
> exception handling like you're doing here, but you can see that if an
> exception is caught, you end up outside the loop. If you added a "retry"
> or "redo" to the rescue clause, you'd simply start the loop again from
> the top.
>
> You can add rescue clauses inside begin..end blocks and also def..end
> method bodies:
>
> def barf
>   raise "some exception"
> rescue RuntimeError
>   puts "some exception was raised"
> end
>
> Now you can go back to your already-working solution from Mike
> Fletcher's post.
>
> Cheers,
> Dave

Thanks for the additional enlightenment Dave, I did see that syntax in some=
=20
sample code but I was getting "Unexpected KRescue or somesuch error. Howeve=
r,=20
now it is working as it should, and I just need to find out how to send=20
Socket a timeout (SO_RCVTIMEO seems not to be defined) but that is another=
=20
post!

Thanks guys,
=2Dd

=2D-=20
darren kirby :: Part of the problem since 1976 :: http://badcomputer.org
"...the number of UNIX installations has grown to 10, with more expected..."
=2D Dennis Ritchie and Ken Thompson, June 1972

--nextPart1873791.A1dPdozLbS
Content-Type: application/pgp-signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.2 (GNU/Linux)

iD8DBQBEgbpZwPD5Cr/3CJgRAhrcAKCzru2LODJV6HFFR5IugLyj+umiHQCgxSmZ
YOAle4D8zpBIE7oJEQwwmjQ=
=h1Ts
-----END PGP SIGNATURE-----

--nextPart1873791.A1dPdozLbS--