Re: fun (not so much) with funopen

[Bruce Korb <bkorb%gnu.org@localhost>]

On 03/16/12 13:22, David Young wrote:
> > If you're going to break something, then go whole hog and fix it so
> > you won't have to break the API ever again. :)
>
> You can avoid breaking the ABI compatibility of uio_fopen(), too, by
> using presence bits to tell which function pointers are (not) available
> like I have in bus_space_tag_create(9).

Presence bits and version numbers are fairly indistinguishable,
but presence bits might be a bit more straight forward.  In either
event, the callee has a way to determine how and whether to process
the data structure passed in by address.

> (I'm grateful to Matt Thomas for pointing out that an ops structure
> alone wouldn't provide ABI compatibility.)

Yeah, I liked working with him all those years ago.  (Hi, Matt!)

Cheers - Bruce