From: Tanaka Akira <akr@...>
Date: 2013-08-27T20:45:16+09:00
Subject: [ruby-core:56825] Re: [ruby-trunk - Feature #8823][Open] Run trap handler in an independent thread called "Signal thread"

2013/8/27 ko1 (Koichi Sasada) <redmine@ruby-lang.org>:
> Feature #8823: Run trap handler in an independent thread called "Signal thread"
> https://bugs.ruby-lang.org/issues/8823

> How about to make an "Signal thread" to run trap handler?

I think it is a right direction.

However, I know trap is used to interrupt a thread.
For example, irb raises an exception in a trap handler.

lib/irb.rb:

    trap("SIGINT") do
      irb.signal_handle
    end
    ...
    def signal_handle
      ...
      case @signal_status
      when :IN_INPUT
...
        raise RubyLex::TerminateLineInput
      when :IN_EVAL
        IRB.irb_abort(self)
      ...
      end
    end

I suspect "raise RubyLex::TerminateLineInput" doesn't work as expected after
your proposal is implemented because the current thread will be the
signal thread.
It is described as the disadvantage:

> == Disadvantage:
> * There is a small compatibility issue because �Thread.current� on a trap handler is not a main thread.

Maybe, you should update irb (and possibly other libraries) as well as
your signal thread implementation.
-- 
Tanaka Akira