From: ara.t.howard@...
Date: 2006-03-31T05:12:21+09:00
Subject: Re: debuggery of extensions from segfault

On Fri, 31 Mar 2006, Matt Maycock wrote:

> I wrote my first extension!
>
> The functions work fine... except when I'm making multiple calls in a loop.
> Then, it segfaults.  I wrote some more code in my extension to output
> equivalent c code to do the same job - even across my multiple data, and it
> does fine.  So I'm thinking either there's some weirdness I don't know
> about, I'm accidentally clobbering some data, or there's a bug in ruby that
> I stumbled across (ruby 1.8.4 (2005-12-24) [powerpc-darwin8.4.0]) - my
> question is, how do I figure this out?  Right now, my plan is to add
> fprintf(stderr, "%s [%d]\n", __FILE__, __LINE__); to the end of every line
> in my c extension and see what gets dumped... but is there an easier way?
>
> Thanks,
>
> ~Matthew Maycock

- write a script called 'a.rb' that uses your ext

- start ruby in gdb using

     gdb `which ruby`

- run at gdb prompt using (assuming a.rb in cwd)

     > run 'a.rb'

- when you seg fault type

     > where


hth.



-a
-- 
share your knowledge.  it's a way to achieve immortality.
- h.h. the 14th dali lama