From: Daniel Berger <djberg96@...>
Date: 2010-01-26T07:18:07+09:00
Subject: Re: Compiling multiple C source files into a single library



On Jan 25, 12:59 pm, Aaron Patterson <aa...@tenderlovemaking.com>
wrote:
> On Tue, Jan 26, 2010 at 04:46:37AM +0900, Daniel Berger wrote:
> > Hi,
>
> > In the past I've always put all my code into a single source file and
> > built it that way. However, I'd like to split out my C source files
> > into a "one class per file" arrangement for a particular project, but
> > I'm not sure how to do it. I'm using rake-compiler on Snow Leopard,
> > btw.
>
> > Here's the layout I have:
>
> > my_project
> >   Rakefile
> >   ext/
> >     foo/
> >       extconf.rb
> >       foo.c
> >       bar.c
>
> > foo.c and bar.c are pretty basic C source files:
>
> > // foo.c
> > #include <ruby.h>
>
> > void Init_foo(){
> >   VALUE cFoo = rb_define_class("Foo", rb_cObject);
> >   rb_define_const(cFoo, "VERSION", rb_str_new2("0.0.1"));
> > }
>
> Call Init_bar() from Init_foo().  Ruby will only call one function when
> your extension loads.  The "Init_*" function maps to the name of the
> shared object you build.  So if you build "foo.bundle", ruby will call
> "Init_foo", and only "Init_foo".  Other initialization is up to you.
>
> > // bar.c
> > #include <ruby.h>
>
> > // I also tried Init_foo here, but that lead to a compiler error
> > void Init_bar(){
> >   VALUE cBar = rb_define_class("Bar", rb_cObject);
> >   rb_define_const(cBar, "VERSION", rb_str_new2("0.0.1"));
> > }
>
> > The extconf.rb file is just "require 'mkmf'; create_makefile('foo')".
>
> The create_makefile() call determines the name of the shared object
> built.  Since you're building "foo.bundle", *only* Init_foo will be
> called.
>
>
>
> > The Rake task is simply "Rake::ExtensionTask.new('foo')".
>
> > Running "rake compile:stuff" builds like so:
>
> > gcc -I. -I/opt/ree/lib/ruby/1.8/i686-darwin10.2.0 -I/opt/ree/lib/ruby/
> > 1.8/i686-darwin10.2.0 -I../../../../ext/foo -D_XOPEN_SOURCE -
> > D_DARWIN_C_SOURCE   -fno-common -g -Os -fno-strict-aliasing  -pipe -
> > fno-common   -c ../../../../ext/foo/bar.c
> > gcc -I. -I/opt/ree/lib/ruby/1.8/i686-darwin10.2.0 -I/opt/ree/lib/ruby/
> > 1.8/i686-darwin10.2.0 -I../../../../ext/foo -D_XOPEN_SOURCE -
> > D_DARWIN_C_SOURCE   -fno-common -g -Os -fno-strict-aliasing  -pipe -
> > fno-common   -c ../../../../ext/foo/foo.c
> > cc -dynamic -bundle -undefined suppress -flat_namespace -o foo.bundle
> > bar.o foo.o -L. -L/opt/ree/lib -L.     -ldl -lobjc
> > cd -
> > cp tmp/i686-darwin10.2.0/foo/1.8.7/foo.bundle lib/foo.bundle
>
> > But, if I run the following test.rb program it fails:
>
> > $:.unshift 'lib'
> > require 'stuff' # ok
> > p Foo::VERSION # ok
> > p Bar::VERSION # fail, uninitialized constant Bar
>
> > Why isn't Bar visible? What's the right way to do what I'm attempting?
>
> Just call Init_bar() from inside Init_foo().
>
> Hope that helps!

Aha, thanks!

Dan