Subject: Re: ancillary data alignment and binary backward compatibility
To: None <firstname.lastname@example.org>
From: Chris G. Demetriou <email@example.com>
Date: 03/11/2000 22:15:30
> I'm very convinced that ALIGNBYTES is correct here. We can't foresee
> what kind of structs are put into ancillary message. If we use
> something smaller than ALIGNBYTES, every time we pass new struct via
> ancillary message (which exceeds the alignment defined) we need to
> change CMSG_ALIGN and we'll have binary compatibility issue.
yeah, i think i believe this, however...
> So, at least need to bump from 3 to ALIGNBYTES.
> - How to bump
> - how to determine ALIGNBYTES (statically by header of hw.alignbytes
> sysctl MIB)
> current tree uses hw.alignbytes
> is still not 100% decided...
ALIGNBYTES is something that can't change for a given MACHINE_ARCH (or
shouldn't, unless there's a big flag day for that port).
There's no reason to do this using a sysctl. it just adds overhead.
Chris Demetriou - firstname.lastname@example.org - http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.