Re: [Caml-list] undefined symbol `caml_tuplify2' in dynamic rocaml extension

[Gordon Henriksen <gordonhenriksen@mac.com>]

On Aug 1, 2007, at 03:44, Julien Moutinho wrote:
> On Tue, Jul 31, 2007 at 09:01:02PM -0700, Jos Backus wrote:
>
>> Hi. I'm trying to use rocaml to wrap an Ocaml library so it can be  
>> accessed from a dynamic Ruby extension (using Callback.register).  
>> Everything works, except when I try to access the Ocaml type from  
>> Ruby the following Ruby LoadError is emitted:
>>
>>     undefined symbol: caml_tuplify2
>>
>> So my question is: what do I need to do in order to satisfy this  
>> symbol? It doesn't appear in any library. ocaml version is 3.09.2.
>
> AFAICS, when needed, caml_tuplifyN end up within the /tmp/ 
> camlstartup*.s file mechanically generated at link time. You can  
> keep this file with -dstartup.
>
> Unfortunately, due to its quasi-random name, it is not easy to  
> retrieve it mechanically.
>
> Personally I have patched ocamlopt in order to have a -startup  
> option keeping camlstartup_<name_of_the_output>.o in the current  
> directory.
>
> Anyway, maybe there is a better way for your own concern. Have a  
> glance at -output-obj perhaps.
>
> HTH.

I wonder if there's a reason ocamlopt doesn't simply emit these glue  
functions alongside their uses as linkonce symbols. This is the same  
technique that a C++ compiler uses for template instantiations to  
avoid problems of this nature.

— Gordon