Fiddle 実験 : 一方同じ内容の文字列から作ったFiddle::Pointerインスタンスを引数として渡せば無駄な生成は起きない(どこかで作られたNULL相当の1個は除く)

fiddletest2.rb

require 'fiddle/import'

module M
  extend Fiddle::Importer
  dlload "/usr/lib/libstdc++.dylib"
  extern "int strcmp(char*, char*)"
  extern "int strlen(char*)"
end

=begin
str0 = "abc"
str1 = "abd"
=end
str0 = Fiddle::Pointer["abc"]
str1 = Fiddle::Pointer["abd"]

p M.strcmp(str0, str0) # => 0
p M.strcmp(str0, str1) # => -1
p M.strcmp(str1, str0) # => 1

p M.strlen(str0) # => 3
p M.strlen(str1) # => 3

ObjectSpace.each_object(Fiddle::Pointer) {|x| p x }
# =>
=begin
#<Fiddle::Pointer:0x00000100ec6bb0 ptr=0x00000000000000 size=0 free=0x00000000000000>
#<Fiddle::Pointer:0x00000100e4be00 ptr=0x0000010191f928 size=3 free=0x00000000000000>
#<Fiddle::Pointer:0x00000100e4bfd0 ptr=0x0000010191f978 size=3 free=0x00000000000000>
=end