Subject: Re: _res_state_ext in resolv.h
To: None <email@example.com>
From: Atsushi Onoe <firstname.lastname@example.org>
Date: 03/15/2000 17:42:48
> > KAME team really need to revisit struct res_state_ext in
> > /usr/include/resolv.h. is it acceptable if I remove it once
> > from the header? Quite unfortunately, libc contains globally
> > accessible symbol:
> > >>extern struct __res_state_ext _res_ext;
> > but I believe noone except libc code ever touches this. This was
> > introduced in sometime June 1999.
I originally introduced this struct into KAME just because there are no room
to extend in struct __res_state. To keep binary compatibility, I cannot
add members to __res_state. I was very careless to forget to reserve
some paddings in __res_state_ext.
There are at least two issues raised.
1. Update resolver to bind8.
resolver in bind8 requires some additional members in
Unlike other platforms, our __res_state has no additional
pad at the end of struct. So we must use some tricks
to migrate into bind8 with keeping binary compatibility.
2. Scoped-aware address sort for resolver.
resolvsort feature in sort_list might be useful to
specify preferences, though it is not clear defined yet.
So KAME team would like to reconsider the way to extend current __res_state
to allow some future extension without breaking compatibility.
> If nothing outside of libc touches it, then yes, please remove it from
> the header file.
There is only one file in source tree.
And at least one in pkgsrc
Both of them are derived from KAME/WIDE.