From: Mat Brown <mat@...>
Date: 2010-02-14T01:11:42+09:00
Subject: Re: Getting started with the C API

On Sat, Feb 13, 2010 at 10:25, Marvin Humphrey <marvin@rectangular.com> wrote:
> Greets,
>
> I've been teaching myself Ruby using David Black's book, "The
> Well-Grounded Rubyist".  5 chapters in or so, things are going well.
> However, things would be going even better if I was able to get
> started on the project that's motivating my course of study: there's a
> C library I'd like to write Ruby bindings for.
>
> The Black book, while appropriate in pace and tone for an experienced
> programmer, doesn't cover any sort of Ruby C API.  The pickaxe book
> does, but before I go and buy a copy of that, I'd like to know if
> those pickaxe chapters are really the canonical reference.  That seems
> weird.
>
> What I'm looking for is the analogue to these pages:
>
>  http://perldoc.perl.org/perlxstut.html
>  http://docs.python.org/3.1/c-api/index.html
>  http://java.sun.com/docs/books/jni/html/jniTOC.html
>
> From what I can tell, the closest thing Ruby has to that is a raw
> Doxygen dump...
>
>  http://www.ruby-doc.org/doxygen/current/
>
> ... but that's not much better than just spelunking the source code,
> because it doesn't give you any idea where to get started.
>
> I know the first edition of the pickaxe book is online, but I don't
> like to waste time learning from dated materials.
>
> Where should I be looking?
>
> Marvin Humphrey
>
>
>

If you download the Ruby source, there's a file called README.EXT
which gives a pretty good, detailed treatment of the Ruby C API.
Better than anything I've seen online. Here it is in the Ruby SVN:
http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_8/README.EXT

This article on Ruby Inside gives you a quick primer on using mkmf to
build a Makefile so you can start playing around with it:
http://www.rubyinside.com/how-to-create-a-ruby-extension-in-c-in-under-5-minutes-100.html