From: "Iñaki Baz Castillo" <ibc@...>
Date: 2011-02-02T23:34:30+09:00
Subject: Re: How to know the exit status within at_exit() block?

2011/2/2 Josh Cheek <josh.cheek@gmail.com>:
>> Really interesting. However, it fails if exit() is called outside of the
>> scope:
>>
>> irb> at_exit { p "$!.inspect = #{$!.inspect}" }
>> #<Proc:0x000000019f99c0@(irb):1>
>> irb> exit 1
>> "$!.inspect = nil"
>>
>> So $! is nil and I cannot get $!.status.

> It probably doesn't work in IRB, because IRB wraps calls to exit
>
> irb> method :exit
> => #<Method: Object(IRB::ExtendCommandBundle)#exit>
>
> I think that using $! is probably what you should do.

You are right, however I've realized that in case of exiting without
invoking "exit" or "exit!" (i.e. exiting due to a signal) then $! is
not a SystemExit instance, but an Interrupt instance (and it doesn't
have "status" method).

For example:

--------------------
at_exit { p "$!.inspect = #{$!.inspect}" }

sleep 10
--------------------

If you run this program and press Ctrl+C prior to 10 seconds you get:

  "$!.inspect = Interrupt"

So, at_exit block is executed but $! is not a SystemExit instance. I
could trap the signals however.

Thanks.

-- 
Iñaki Baz Castillo
<ibc@aliax.net>