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Re: fun (not so much) with funopen

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

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