Subject: Re: Breaking binary compatibility for /dev/joy
To: None <>
From: None <>
List: tech-kern
Date: 04/16/2002 17:19:23
At Wed, 17 Apr 2002 00:10:04 +0000 (UTC), "Jared D. McNeill" wrote:
> Would anybody horribly mind if I broke binary compatibility for
> applications that use /dev/joy*?
> I've added 4-button support to the analog joystick driver, but that
> required adding two more items to struct joystick (for the two extra
> buttons).
> Current applications should still be source compatible.
> Any objections?

Well, there are various easy ways you could do this without breaking
binary compatiblity.  (e.g., ioctl which causes you to use a new,
larger structure.  or throwing the additional buttons into additional
bits of the b1/b2 fields.)

the former wouldn't be hard to implement, and could be completely

add new members & end of new structure, and verify that it would pack
like old structure... then just fill everything in, and use something
other than 'sizeof (struct joystick)' in the call to uiomove in
joyread, eh?