From: Robert Klemme <bob.news@...>
Date: 2004-12-20T18:22:06+09:00
Subject: Re: threads and errors


"Charles Mills" <cmills@freeshell.org> schrieb im Newsbeitrag
news:1103500878.714949.188970@c13g2000cwb.googlegroups.com...
> What techniques are available for handling errors that occur in
> threads?
>
> For example how do I find out that an error occured in t below?
>
> t = Thread.new { raise "error" }
>
> I need to be able to check on the error status of threads from their
> parent.  Something like the following would be ideal - but I know this
> won't do what I want:
>
> begin
> Thread.new { raise "error"}
> rescue
> puts $! # in a strange world prints "error", but in actuality does
> nothing
> end

Apart from the other proposed solutions you can catch the exception at the
main level of the thread (Test 0) or you can use
"Thread.abort_on_exception = true" (Test 1 and 2):

10:20:08 [ruby]: ruby thread-abort-test.rb
#<RuntimeError: Test 0>
thread-abort-test.rb:2
thread-abort-test.rb:4
thread-abort-test.rb:6
thread-abort-test.rb:7: Test 2 (RuntimeError)
        from thread-abort-test.rb:7:in `initialize'
        from thread-abort-test.rb:7:in `new'
        from thread-abort-test.rb:7
10:20:19 [ruby]: cat thread-abort-test.rb
Thread.new { begin; raise "Test 0"; rescue Exception => e; p e; end }
puts "#{__FILE__}:#{__LINE__}"
Thread.new { raise "Test 1" }
puts "#{__FILE__}:#{__LINE__}"
Thread.abort_on_exception = true
puts "#{__FILE__}:#{__LINE__}"
Thread.new { raise "Test 2" }
puts "#{__FILE__}:#{__LINE__}"

Kind regards

    robert