From: E S <eero.saynatkari@...>
Date: 2005-02-09T16:00:57+09:00
Subject: Re: A couple of Ruby API questions

> L�hett�j�: Jon McClintock <jammer@weak.org>
> Aihe: A couple of Ruby API questions
> 
> Hi Rubyists,
> 
> I'm working on wrapping a C library, and I've got a couple of things I
> can't quite figure out how to manage:
> 
> 1) Wrapping functions that take variable-length arguments (varargs). Is 
>    there are standard way to do this? The best I've found is libffi,
>    which lets you construct the stack frames you need to do this, but it
>    seems like this would be a problem someone would have solved a while
>    ago.

Wrapping how? Should these be callable from Ruby? Ruby can define a 
method to take variable arguments either as a RArray or as a C array,
so you'll pick one, construct a wrapper function based your selected
way and have that function extract the values and feed them to your 
'actual' function.

> 2) Wrapping structures with flexible arrays. How do I realloc the
>    structure held by a VALUE? Or do I have to create an entirely new
>    Ruby object each time I need to resize the structure?

Just wrap a pointer to the struct instead if you already have the C
to manage the arrays. Whenever Ruby needs those values, have a C 
function extract them. Alternatively, you could use a RArray.
 
> Thanks,
> 
> -Jon

E