Re: device delete to get errors from the kernel

[Anand Jain <Anand.Jain@oracle.com>]

  Thanks Stefan.

::

> About the issue you mentioned, that you need to change the kernel and
> the user mode at the same time:
> You can keep it compatible. Just do not delete the old kernel interface.
> The user mode program could try the new interface first, and if it
> fails, fall back to the old interface. You can use the same ioctl number
> for both ways if you change the length of the ioctl parameter.

  Here there won't be a definite failure as such,
  kernel could send or read garbage if the old and
  new structures don't match.

  The problem with most of the ioctl api structures
  are they don't (already) share the struct len. So
  it won't be possible to know which version of the
  structure is being used by the other party?

Anand