From: Timothy Hunter <cyclists@...>
Date: 2005-06-24T08:40:37+09:00
Subject: Re: setup.rb question

Bill Kelly wrote:
> Hi,
> 
> I'm packaging a ruby extension, and want setup.rb to perform 
> a particular part of the install only on a particular platform.
> 
> I figure others may have dealt with this with their own 
> extensions, and I was wondering how it's usually done.
> 
> On win32, I'm including a pre-built .dll that my extension
> requires, because it's kind of a pain to build on windows.
> I've put the .dll in the bin/ directory - and setup.rb does
> the right thing (for windows) and installs the .dll alongside
> the ruby.exe binary, wherever that may be on the system.
> 
> However, on Linux, the shared library .so's needed by the
> extension a) are easy to build, so I see no need to include
> pre-built ones, and b) don't belong next to the ruby 
> executable anyway... and c) I certainly don't want the
> win32 .dll copied into /usr/bin or wherever on Linux.  :)
> 
> So my question is how to have setup.rb do the right thing
> on windows with the files in ./bin (which it currently is)...
> and basically ignore the files in ./bin on Linux.
> 
> Is it typical to just hack setup.rb to add the desired
> behavior?  Just wondering how it's usually done.
> 

setup.rb support a set of 8 "hooks" that you might be able to leverage. 
You can create a hook to run before or after each of setup's config, 
setup, install, and clean steps. Each hook is just a fragment of Ruby 
code that setup runs if it's present. Setup defines a few APIs that the 
hook code can use to find out about the configuration. 
(http://i.loveruby.net/en/man/setup/hookapi.html)

Just thinking out loud, maybe you could put the .dll somewhere other 
than bin (to keep setup from automatically installing it) and then 
create a post-install hook that copied the .dll only for Windows installs.

There's probably a better way but still I don't think you should have to 
hack setup.rb itself.