Ruby Extension in "hello, world!"

example-ext-test.rb

#!/usr/bin/env ruby

$:.unshift "example.ext"

require "example"

puts Example.new.just_hello
puts Example.new.hello("shelling")

example.c

#include <stdio.h>
#include <ruby.h>

static VALUE cExample;


static VALUE
just_hello (VALUE object)
{
  return rb_str_new2("hello");
}


static VALUE
hello (VALUE object, VALUE string)
{
  VALUE arr = rb_str_new2("hello, ");
  rb_str_concat(arr, string);
  rb_str_concat(arr, rb_str_new2("!"));
  return arr;
}

void 
Init_example () 
{
  cExample = rb_define_class("Example", rb_cObject);
  rb_define_method(cExample, "just_hello", just_hello, 0);
  rb_define_method(cExample, "hello", hello, 1);
}

extconf.rb

require "mkmf"

dir_config "example"
create_makefile "example"