Re: Cleaning up FILE in stdio..

On Wednesday 27 February 2008 12:14:59 am Garrett Wollman wrote:
In article <Pine.GSO.4.64.0802262351060.11586@xxxxxxxxxxxxx>,
Daniel Eischen <deischen@xxxxxxxxxxx> writes:
[I wrote:]
I think you have the right idea but this will break the ABI in a way
that can't be fudged with symbol versioning.

Well, you can if you add compat symbols for all functions with FILE
as an argument.

In every library, including hundreds of third-party libraries that
pass FILE * arguments? I don't think so.

What would work, although it would be extra pain, would be to extend
the structure. It would be necessary to keep compatibility members of
the structure, in their old locations, and update them to reflect
state changes appropriately. If the only thing that will change is
the width of _file, then that's probably a workable approach, since it
doesn't break anything that wasn't already broken in the presence of
FD 65536 anyway. Applications aren't permitted to store objects of
type FILE, only FILE *, so this should be safe.

Actually FD 32768. 32768 gets sign extended when the short is promoted to an
int. I guess we could add a _nfile that is an int, and try to keep _file up
to date for older apps. Newer apps would just always use _nfile. (Or
better, rename _file to _ofile and make the new one _file but at new
location). I'll work on that next then.

--
John Baldwin
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