From: Joel VanderWerf <vjoel@...>
Date: 2007-07-13T07:25:40+09:00
Subject: Re: getting gdb backtrace from ruby exception

ara.t.howard wrote:
> 
> On Jul 12, 2007, at 8:10 AM, Alex Fenton wrote:
> 
>> Hi
>>
>> I'm working on a C extension and somewhere in itsomething is raising a 
>> NoMethodError. The exception is reported with the line of ruby code 
>> that triggered the bad call in the C extension.
>>
>> As the C code is large and complex (it's a big SWIG project), I'm 
>> having trouble finding the problem in the C code. I would use gdb or 
>> Microsoft's debugger to look at the stack if it was a C error - but 
>> when a Ruby exception is raised, the process exits and there's no 
>> stack to inspect.
>>
>> Ruby's debugger isn't helpful because it only knows about ruby written 
>> in ruby.
>>
>> Is there any way I can get at the C stack at the point of ruby 'raise' 
>> from a C extension?
>>
>> Thanks
>> alex
>>
> 
> 
> cfp:~ > cat core.rb
> BEGIN{ at_exit{ Process.kill 'SIGSEGV', Process.pid if $! } }
> 
> 
> cfp:~ > cat a.rb
> #! /usr/bin/env ruby
> require 'core'
> p 42
> cfp:~ > ruby a.rb
> 42
> 
> 
> cfp:~ > cat b.rb
> #! /usr/bin/env ruby
> require 'core'
> raise
> 
> 
> cfp:~ > ruby b.rb
> ./core.rb:1: [BUG] Segmentation fault
> ruby 1.8.6 (2007-03-13) [i686-darwin8.9.1]
> 
> Abort trap (core dumped)

Doesn't that only give you the C stack at the time the ruby process 
exits, not at the time the exception is raised?

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407