Ruby2.0標準ライブラリ・FiddleでDLLの関数を呼ぶテスト libRMath3D.dylib (https://github.com/vaiorabbit/rmath3d) の RVec4SetElements をRubyから呼ぶところまで。 ruby-ffi で似たことをやったときの記録→ http://gist.github.com/vaiorabbit/6048201

rmath3d_fiddle.rb

# Ref.: http://doc.ruby-lang.org/ja/2.0.0/library/fiddle=2fimport.html
require 'fiddle'
require 'fiddle/import'

module RMath3D
  extend Fiddle::Importer

  dlload Fiddle.dlopen( 'libRMath3D.dylib' )

  RVec4 = struct ['double x', 'double y', 'double z', 'double w']

  extern 'void RVec4SetElements( void*, double, double, double, double )'
end


if __FILE__ == $0
  v = RMath3D::RVec4.malloc
  v.x = v.y = v.z = v.w = 0.0
  puts "v.x=#{v.x}, v.y=#{v.y}, v.z=#{v.z}, v.w=#{v.w}"
  RMath3D::RVec4SetElements( v, 1, 2, 3, 4 )
  puts "v.x=#{v.x}, v.y=#{v.y}, v.z=#{v.z}, v.w=#{v.w}"
end