[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <48122CB0.7020003@zytor.com>
Date: Fri, 25 Apr 2008 12:10:40 -0700
From: "H. Peter Anvin" <hpa@...or.com>
To: Matthew Wilcox <matthew@....cx>
CC: Linus Torvalds <torvalds@...ux-foundation.org>,
Jan Engelhardt <jengelh@...putergmbh.de>,
Andrew Morton <akpm@...ux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux Arch Mailing List <linux-arch@...r.kernel.org>
Subject: Re: [PATCH 01/24] types: create <asm-generic/int-*.h>
Matthew Wilcox wrote:
>
> So ... given all this, why do we define s64 to be 'long' on some
> architectures and 'long long' on others? It seems to actively _hinder_
> passing it to printf(), so there must be some other good reason that
> I'm missing to not make it 'long long' everywhere.
>
Well, compatibility with userspace is probably one aspect of that.
x86-64 is the odd man out there, it defines __s64 as "long long" even
for userspace, even though int64_t from <stdint.h> is "long". This,
IMO, is the Wrong Thing, but it's a separate set of changes.
The right thing to do is probably to always use "long long" in the
kernel, while defining __s64 et al as "long" on 64-bit platforms when
not under __KERNEL__.
Again, this is a separate set of changes from this patchset, which is
just a code transformation.
-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists