Ruby: get drives on Windows

#!/usr/bin/env ruby

require 'win32/api'
include Win32

get_logical_drive_strings = API.new('GetLogicalDriveStrings', 'IP', 'I')

BUFLEN = 260
buf = 0.chr * BUFLEN

rc = get_logical_drive_strings.call(BUFLEN, buf)
if (0..BUFLEN) === rc
    puts buf[0..rc-1].split("\x00")
else
    puts "buffer too small"
end