Conditional compilation of C extensions in Ruby 1.9Edit

Created , updated

Was just wondering how to do conditional compilation of a Ruby C extension for Ruby 1.8/1.9.

My first attempt didn’t work, but I was able to implement a working solution after finding this tip here.

It basically consists of adding some lines like this to your extconf.rb:

case RUBY_VERSION
when /\A1\.8/
  $CFLAGS += ' -DRUBY_1_8_x'
when /\A1\.9/
  $CFLAGS += ' -DRUBY_1_9_x'
else
  raise "unsupported Ruby version: #{RUBY_VERSION}"
end

And then in your C code you can:

#if defined(RUBY_1_9_x)
    ...
[/tags/elif #elif] defined(RUBY_1_8_x)
    ...
[/tags/else #else]
[/tags/error #error] unsupported RUBY_VERSION
[/tags/endif #endif]