From: Tim Hunter <cyclists@...>
Date: 2004-04-21T08:04:07+09:00
Subject: Re: C ext best practices

On Tue, 20 Apr 2004 13:43:34 -0600, Ara.T.Howard wrote:

> 
> rubyists-
> 
> i'm wrapped a little libary that already has a full on gnu autotools
> installation, call it
> 
>   libfoobar-0.0.0.tgz
> 
> obviously, this unpacks like
> 
>   libfoobar-0.0.0/
>   libfoobar-0.0.0/README
>   libfoobar-0.0.0/configure
>   libfoobar-0.0.0/foobar.c
> 
> if i were to wrap this package for ruby, i'd like to be able to
> 
>   require 'foobar'
> 
> what is the preferred means to make an extenstion like this?
> 
>   * foobar.c defines ruby bindings and extconf.rb must be called with
>   '--with-foobar-dir' pointing to an install of libfoobar?
> 
>   * _foobar.c defines ruby bindings and all libfoobar source files are
>   simply
>     dropped in same directory such that
> 
>       ruby extconf.rb
>       make
> 
>     results in a foobar.so containing all required stuff?
> 
> thoughts?
> 
> -a

Well, I won't argue that it's "best practices" but here's what RMagick
does. RMagick assumes that the ImageMagick library, libMagick, has already
been installed in a separate step.

RMagick uses the standard GNU ./configure, make, make install sequence.
The configure script (built by autoconf) handles any
non-Ruby configuration - such as finding libMagick - and builds a custom
Makefile, extconf.rb, and a metaconfig file for install.rb. The Makefile's
all: target runs install.rb's config and setup steps. The Makefile's
install: target runs install.rb's install step.

Here's RMagick's Makefile.in. This will probably make it clearer than my
prose description. (The ./configure script also accepts a number of
options, like --with-std-ruby, that it passes on to install.rb via
@RUBY_CONFIG_OPTS@.)

# Path to ruby interpreter
RUBY=@RUBY@

# Any extra options from configure script to pass to 'install.rb config'
RUBY_CONFIG_OPTS=@RUBY_CONFIG_OPTS@

all: config.save
	$(RUBY) install.rb setup

install:
	$(RUBY) install.rb install

clean: config.save
	$(RUBY) install.rb clean

distclean: config.save
	$(RUBY) install.rb clean
	rm -f Makefile ext/RMagick/extconf.rb metaconfig
	rm -f config.status Makefile config.cache config.log
	rm -rf autom4te.cache

uninstall: config.save
	$(RUBY) uninstall.rb $(RUBY_CONFIG_OPTS)

config.save: metaconfig
	$(RUBY) install.rb config $(RUBY_CONFIG_OPTS)