From: Ian Jackson <iwj@xenproject.org>
To: Manuel Bouyer <bouyer@antioche.eu.org>, Jan Beulich <jbeulich@suse.com>,
Cc: Wei Liu <wl@xen.org>, Anthony PERARD <anthony.perard@citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Julien Grall <julien@xen.org>,
Stefano Stabellini <sstabellini@kernel.org>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH] Fix error: array subscript has type 'char'
Date: Tue, 26 Jan 2021 17:59:57 +0000 [thread overview]
Message-ID: <24592.22685.67161.585056@mariner.uk.xensource.com> (raw)
In-Reply-To: <20210126174415.GA21858@mail.soc.lip6.fr>
Manuel Bouyer writes ("Re: [PATCH] Fix error: array subscript has type 'char'"):
> On Thu, Jan 14, 2021 at 03:16:15PM +0100, Manuel Bouyer wrote:
> > On Thu, Jan 14, 2021 at 02:25:05PM +0100, Jan Beulich wrote:
> > > Which means you're shifting the undefined-ness from the implementation
The undefined-ness is in the *specification*. [1]
> > > Isn't this something that wants changing in your ctype.h instead?
> > > the functions (or macros), as per the C standard
Jan, can you please check your facts before asserting the existence
of a pretty blatant bug in a platform's implementation of basic C
functions ?
From my copy of C99+TC1+TC2, para 7.4:
1 In all cases the argument is an int, the value of which shall be
representable as an unsigned char or shall equal the value of the
macro EOF. If the argument has any other value, the behavior is
undefined. [...]
If char is signed, then it can contain -ve values. Those values are
promoted to int by the usual integer promotions. Naturally such
negative values are not representable as unsigned char. Passing them
to ctype macros is UB.
So Manuel's ctypes.h is conforming and the compiler warning (which I
have seen on Linux too) is correct.
> I guess I'm going to give up on this one. We'll keep it as a local patch.
Manuel, your original patch:
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Release-Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(The R-A is FTAOD since IMO this is a bugfix.)
Ian.
[1] I agree that "fixing" ctypes.h everywhere might be nice (eg the
way glibc does it) but that has other implications and it is not
reasonable to expect platforms supporting Xen to do that.
next prev parent reply other threads:[~2021-01-26 18:00 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 18:12 [PATCH] Fix error: array subscript has type 'char' Manuel Bouyer
2021-01-12 18:12 ` [PATCH] NetBSD: Fix lock directory path Manuel Bouyer
2021-01-15 15:09 ` Roger Pau Monné
2021-01-15 15:13 ` Manuel Bouyer
2021-01-15 15:30 ` Andrew Cooper
2021-01-12 18:12 ` [PATCH] NetBSD hotplug: Introduce locking functions Manuel Bouyer
2021-01-27 15:57 ` Ian Jackson
2021-01-27 19:29 ` Manuel Bouyer
2021-01-28 14:05 ` Ian Jackson
2021-01-12 18:12 ` [PATCH] NetBSD hotplug: fix block unconfigure on destroy Manuel Bouyer
2021-01-15 15:27 ` Roger Pau Monné
2021-01-26 16:47 ` Manuel Bouyer
2021-01-27 9:40 ` Roger Pau Monné
2021-01-27 9:47 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] NetBSD hotplug: handle case where vifname is not present Manuel Bouyer
2021-01-15 16:06 ` Roger Pau Monné
2021-01-26 16:49 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] NetBSD: remove xenbackendd Manuel Bouyer
2021-01-15 15:31 ` Roger Pau Monné
2021-01-18 18:31 ` Andrew Cooper
2021-01-18 18:41 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] NetBSD: use system-provided headers Manuel Bouyer
2021-01-15 16:01 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] gdbsx: use right path for privcmd Manuel Bouyer
2021-01-18 18:03 ` Roger Pau Monné
2021-01-18 18:45 ` Andrew Cooper
2021-01-18 19:05 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] libs/call: fix build on NetBSD Manuel Bouyer
2021-01-18 18:00 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/evtchn: " Manuel Bouyer
2021-01-18 18:01 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/foreignmemory: Implement " Manuel Bouyer
2021-01-18 17:49 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/gnttab: implement " Manuel Bouyer
2021-01-18 17:54 ` Roger Pau Monné
2021-01-26 17:05 ` Manuel Bouyer
2021-01-27 9:31 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/light: Switch NetBSD to QEMU_XEN Manuel Bouyer
2021-01-18 17:28 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/light: fix tv_sec printf format Manuel Bouyer
2021-01-18 18:19 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/light: fix uuid on NetBSD Manuel Bouyer
2021-01-15 17:27 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] libs/light: make it build without setresuid() Manuel Bouyer
2021-01-18 18:16 ` Roger Pau Monné
2021-01-20 14:52 ` Ian Jackson
2021-01-20 15:13 ` Manuel Bouyer
2021-01-20 15:32 ` Ian Jackson
2021-01-20 16:56 ` Manuel Bouyer
2021-01-20 17:10 ` Ian Jackson
2021-01-20 17:20 ` Manuel Bouyer
2021-01-20 17:29 ` Ian Jackson
2021-01-27 16:03 ` Ian Jackson
2021-01-27 19:34 ` Manuel Bouyer
2021-01-28 11:39 ` Ian Jackson
2021-01-30 11:57 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] libs/light: pass some infos to qemu Manuel Bouyer
2021-01-16 10:16 ` Roger Pau Monné
2021-01-16 11:25 ` Manuel Bouyer
2021-01-18 8:36 ` Roger Pau Monné
2021-01-18 8:52 ` Manuel Bouyer
2021-01-18 9:07 ` Roger Pau Monné
2021-01-18 9:24 ` Manuel Bouyer
2021-01-26 22:42 ` Manuel Bouyer
2021-01-27 9:06 ` Roger Pau Monné
2021-01-27 9:49 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] libs/store: make build without PTHREAD_STACK_MIN Manuel Bouyer
2021-01-18 18:18 ` Roger Pau Monné
2021-01-18 18:56 ` Andrew Cooper
2021-01-18 19:05 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] ocaml/libs/eventchn: drop unneeded evtchn.h Manuel Bouyer
2021-01-13 9:22 ` Christian Lindig
2021-01-13 9:40 ` Manuel Bouyer
2021-01-12 18:12 ` [PATCH] xenpaging.c: include errno.h Manuel Bouyer
2021-01-15 16:08 ` Roger Pau Monné
2021-01-12 18:12 ` [PATCH] xenpmd.c: use dynamic allocation Manuel Bouyer
2021-01-27 15:57 ` Ian Jackson
2021-01-12 18:12 ` [PATCH] xenstat_netbsd: remove usused code Manuel Bouyer
2021-01-18 18:06 ` Roger Pau Monné
2021-01-14 10:53 ` [PATCH] Fix error: array subscript has type 'char' Jan Beulich
2021-01-14 12:29 ` Manuel Bouyer
2021-01-14 13:25 ` Jan Beulich
2021-01-14 14:16 ` Manuel Bouyer
2021-01-26 17:44 ` Manuel Bouyer
2021-01-26 17:59 ` Ian Jackson [this message]
2021-01-27 8:31 ` Jan Beulich
2021-01-27 8:37 ` Jan Beulich
2021-01-27 13:53 ` [PATCH] Fix error: array subscript has type 'char' [and 1 more messages] Ian Jackson
2021-01-27 14:33 ` Jan Beulich
2021-01-27 16:21 ` Ian Jackson
2021-01-27 16:32 ` Jan Beulich
2021-01-27 16:52 ` George Dunlap
2021-01-27 17:00 ` Jan Beulich
2021-01-27 17:00 ` Ian Jackson
2021-01-18 19:08 ` NetBSD patches Andrew Cooper
2021-01-18 19:11 ` Manuel Bouyer
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