From: Tim Pease <tim.pease@...>
Date: 2010-06-05T00:19:35+09:00
Subject: Re: Use a core C function not included in intern.h


On Jun 3, 2010, at 6:48 PM, Shinku Fag wrote:

> Hello.
> 
> I trying to make a function with C extension for 1.8.7 that should use
> functions defined in Ruby such as
>> VALUE eval(VALUE,VALUE,VALUE,const char*,int)
> But functions that aren't reflected (sorry, I don't know how to call it
> better r_r) in intern.h, seems to be unusable. If I just add string
>> VALUE eval _((VALUE,VALUE,VALUE,const char*,int));
> to extension source or intern.h then I get
>> symbol lookup error: /usr/lib/ruby/gems/1.8/gems/rmtools-1.0.0/lib/rmtools.so: undefined symbol: eval
> 
> So, is there a way to use such functions in the extension without
> copypasting half the eval.c (and maybe even something else) into it?
> 

The "eval" method in the eval.c source file is marked as static. It cannot be called from outside the eval.c source file. This is a feature of the compiler/linker, and to the best of my knowledge there is no easy way around it.

If someone with more recent C experience could chime in, it would be appreciated. My C is a little rusty, and would love for someone to double check my facts.

Blessings,
TwP