locale.rb

gistfile1.rb

require 'ffi'

class Time
  module Strftime
    extend FFI::Library
    ffi_lib 'c'
    attach_function :setlocale, [:int, :string], :uint
    attach_function :strftime, [:string, :long, :string, :pointer], :long
    setlocale(LC_ALL = 6, "de_DE")
  end

  def strftime_c(format)
    struct = to_a
    struct[-2] = struct[-2] ? 1 : 0
    tm = FFI::MemoryPointer.from_string(struct.pack('iiiiiiiilZ*'))
    str = "\xff" * 1024
    len = Strftime.strftime(str, str.length, format, tm)
    str[0, len]
  end
end

now = Time.now
p ruby: now.strftime('%a')
p libc: now.strftime_c('%a')


__END__
require 'dl'
require 'dl/import'

module Time::Strftime
  extend DL::Importer

  begin
    dlload 'libc.so'
  rescue DL::DLError
    begin
      dlload 'libc.so.6'
    rescue DL::DLError
      dlload 'libSystem.dylib'
    end
  end

  extern 'long strftime(char *, long, char *, struct tm *)'
  extern 'char *setlocale(int, char *)'
end

class Time
  def strftime_c format
    struct = to_a
    struct[-2] = struct[-2] ? 1 : 0
    tm = struct.pack 'iiiiiiiilZ*'

    str = "\0" * 1024

    len = Time::Strftime.strftime str, str.length, format, tm

    str[0, len]
  end
end

puts `locale`

Time::Strftime.setlocale(6, "")
now = Time.now
p ruby: now.strftime('%a')
p libc: now.strftime_c('%a')