Subject: Re: struct msgbuf contents.
To: Matt Thomas <firstname.lastname@example.org>
From: Simon Burge <email@example.com>
Date: 06/13/2000 15:34:27
Matt Thomas wrote:
> At 01:19 PM 6/13/2000 +1000, Simon Burge wrote:
> >Locally, I've changed the members of 'struct msgbuf' from "long" to
> >"int64_t" to make 'struct msgbuf' compat32 friendly. I've not had any
> >problems on either alpha or i386 other than the old msgbuf looking a bit
> >funny on i386 - I suspect it would fail the magic test on sparc due to
> That's wrong, IMO. If anything change them to int32_t.
I just tried int32_t and it works fine ok. A 32 bit limit on the size
of msgbuf obviously shouldn't worry anyone...
> The overhead of
> int64 is unacceptable on many of the older platforms.
Do you have any figures for how a vax or m68k deals with say adding two
> If you are going to
> make things compat32 friendly, that's fine. but don't make things worse
> for platforms that will never use compat32.
> Personally, I think if you are going to run 32bit programs on a 64bit
> platform, you should expect a little performance hit.
It's not performance (either way) that I'm worrying about - it's getting
the data back in a known format regardless of any differences between
the userland and kernel size. I'm open to better/easier/quicker-natively
ways of doing this.