From: Hugh Sasse <hgs@...>
Date: 2005-11-03T20:53:13+09:00
Subject: Re: Trapping errors.

On Thu, 3 Nov 2005, Robert Klemme wrote:

> Hugh Sasse wrote:
> > On Thu, 3 Nov 2005, Robert Klemme wrote:
> >
> >> This sounds really strange.  Here's what I'd do: use set_trace_func
> >> to write out all method invocations, returns and thread ids and try
> >> to see where it goes.  HTH
> >
> > Good job I tried to add docs to profiler.rb in stdlib yesterday.
> > I'll have a go at that.  I've not played with set_trace_func before,
> > so it should be interesting.
> 
> This should get you started:
> 
> set_trace_func lambda {|event, file, line, id, binding, classname|
>   $stderr.printf "th %10d: %-10s %s: %d\n", Thread.current.object_id,
> event, file, line if
>     /call|return/ =~ event
> }
> 
> Good luck!

thanks.  It did the trick.  I was hoisted by my own petard.

      begin
        copy_entry s, d, options[:preserve], options[:dereference_root]
      rescue Exception, SystemCallError => e
        stop = true
        if block_given?
          stop = yield s,d,e
        end
        raise if stop
      end

Yes, I forgot to return nil from the *flaming* block! So it re-raised
because stop was true.  

I didn't realize set_trace_func could be so useful.  I'd previously
considered it obscure.  Thank you for helping me out with this.  

> 
>     robert
> 

        Hugh