That fixed the crashes with 1.9.1 but I am still seeing some odd behavior. It may be a bug on my side, so I'll play with it a while longer.

Many thanks...

cr

On May 12, 2010, at 6:29 PM, Wayne Meissner wrote:

> Can you build ffi from github and retry it on 1.9?  I added special
> support for callbacks from non-ruby threads (only works on 1.9 though
> - 1.8 is completely screwed in that situation).
> 
> JRuby has no problem, because upcalls from C -> java always check &
> attach a JVM context, and jruby automagically adopts threads it does
> not know about.
> 
> 
> On 13 May 2010 05:53, Chuck Remes <cremes.devlist@mac.com> wrote:

>> I'm starting to work with callbacks and have run into a consistent crasher. Take a look at the trace here:
>> 
>> http://gist.github.com/398987
>> 
>> I downloaded the ruby-1.9.1 source and poked through vm_eval.c which contains the vm_call0() function. There is a big switch statement in there that falls through to calling rb_bug().
>> 
>> This all occurs *only* when invoking the callback. The stack trace clearly shows it is invoking a block (rb_funcall2) from the FFI library. It crashes regardless of the contents of the block (empty, puts, nil, etc.).
>> 
>> In 1.8.7 it crashes with a LocalJumpError somewhere else.
>> 
>> When I disable the callback, there are no crashes under either MRI.
>> 
>> Under JRuby, everything works fine. The callback is invoked successfully.
>> 
>> I'm wondering if this is failing because the callback may be invoked by another native thread. The library being wrapped by FFI spawns many threads that do various background tasks; one of them is likely the invocation of the cleanup callback that is causing the crash.
>> 
>> Are there any known issues with MRI, FFI and callbacks?
>> 
>> cr
>> 
>>