This structure is used in the following IOCTL fns:
    440cH 4aH (select code page)
    440cH 6aH (query current code page)
    DvRq 13H  (generic IOCTL for character devices)

  Offset Size Contents
  ▀▀▀▀▀▀ ▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    +0     2  wLength      length of the rest of this structure (0002)
    +2     2  wCpId        the code page number
           4               length of an IoctlCpIdRec structure

See Also: fn 440cH (Generic IOCTL for character devices)
          National Language Support
          Device Drivers
          DOS Functions