(defun my-snd-aset-i32 (bytearray index x)
  (aset bytearray index (logand 255 (ash x -24)))
  (aset bytearray (+ index 1) (logand 255 (ash x -16)))
  (aset bytearray (+ index 2) (logand 255 (ash x -8)))
  (aset bytearray (+ index 3) (logand 255 x)))

(defun my-snd-aset-i16 (bytearray index x)
  (aset bytearray index (logand 255 (ash x -8)))
  (aset bytearray (+ index 1) (logand 255 x)))

(defconst my-snd-byte-size-i16 2)
(defconst my-snd-amplitude-i16 32767)

(defun my-snd-aset-sin-wave (dst-buffer dst-index num-samples wavelength)
  (let ((2pi/wavelength (/ (* 2 pi) wavelength))
        (i 0))
    (while (< i num-samples)
      (my-snd-aset-i16 dst-buffer dst-index
                       (truncate (* my-snd-amplitude-i16
                                    ;;周期の誤差をどこまで許容するかよく分からないよね
                                    (sin (* i 2pi/wavelength)))))
      (setq dst-index (+ dst-index my-snd-byte-size-i16))
      (setq i (1+ i))))
  dst-buffer)

(defun my-snd-generate-au-sin-wave-440hz-1sec ()
  (let* ((samples-per-sec 44100)
         (seconds 1)
         (num-samples (* seconds samples-per-sec))
         (data-size (* my-snd-byte-size-i16 num-samples))
         (data (make-string (+ 24 data-size) 0)))
    ;; header
    (my-snd-aset-i32 data 0 #x2e736e64)
    (my-snd-aset-i32 data 4 24) ;;Data offset
    (my-snd-aset-i32 data 8 data-size)
    (my-snd-aset-i32 data 12 3) ;;16-bit linear PCM
    (my-snd-aset-i32 data 16 samples-per-sec)
    (my-snd-aset-i32 data 20 1) ;;Channels
    ;; data
    (my-snd-aset-sin-wave data 24 num-samples (/ samples-per-sec 440.0))

    data))

(play-sound (list 'sound :data (string-as-unibyte ;;string-as-unibyte必要?
                                (my-snd-generate-au-sin-wave-440hz-1sec))))

(with-temp-file "~/tmp/sin440.au"
  (set-buffer-file-coding-system 'no-conversion)
  (insert (string-as-unibyte (my-snd-generate-au-sin-wave-440hz-1sec))))

(play-sound '(sound :file "~/tmp/sin440.au"))

#else /* WINDOWSNT */
  /*
    Data is not supported in Windows.  Therefore a
    File name MUST be supplied.
  */
  if (!STRINGP (attrs[SOUND_FILE]))
    {
      return 0;
    }
#endif /* WINDOWSNT */