From: Matthew Bloch <mattbee@...>
Date: 2002-06-30T01:47:54+09:00
Subject: Getting a full backtrace from Thread#join?

Here's a program that demonstrates some unhelpful output:

  def countdown(n)
    if n == 0
      raise Exception.new
    else
      countdown(n-1)
    end
  end

  a = Thread.new { countdown(5) }

  begin
    a.join
  rescue Exception => ex
    print "#{ex}\n"
    print ex.backtrace.join("\n")
    print "\n"
  end

The backtrace I see looks like this:

  Exception
  bt:3:in `countdown'
  bt:12:in `join'
  bt:12

Problem is that only the first line of the backtrace belongs to the thread 
which threw the exception (whereas I should see 5 nested calls to 
'countdown').  I'm trying to weed out an exception in a multithreaded 
application and one line of backtrace isn't enough; is there any way of 
getting hold of the thread's full backtrace?

-- 
Matthew