From: Jon Flatley <jflat@chromium.org>
To: Joe Perches <joe@perches.com>
Cc: Jon Flatley <jflat@chromium.org>, Louis Taylor <louis@kragniz.eu>,
gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux@googlegroups.com,
Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH v2] wusb: use correct format characters
Date: Thu, 28 Feb 2019 16:03:55 -0800 [thread overview]
Message-ID: <CACJJ=pz50c3oovHbKkjDDF=pabAj_9RtKGWvtpwx4nO+E_EtJg@mail.gmail.com> (raw)
In-Reply-To: <1450785b937f4a2b5f98c8548986b162684a719b.camel@perches.com>
On Thu, Feb 28, 2019 at 3:05 PM Joe Perches <joe@perches.com> wrote:
>
> On Thu, 2019-02-28 at 14:23 -0800, Jon Flatley wrote:
> > Thanks for the patch and comments.
> >
> > On Thu, Feb 28, 2019 at 1:53 PM Joe Perches <joe@perches.com> wrote:
> > > On Thu, 2019-02-28 at 12:24 +0000, Louis Taylor wrote:
> > > > When compiling with -Wformat, clang warns:
> > > > ./include/linux/usb/wusb.h:245:5: warning: format specifies type
> > > > 'unsigned short' but the argument has type 'u8' (aka 'unsigned char')
> > > > [-Wformat]
> > > > ckhdid->data[0], ckhdid->data[1],
> > > > ^~~~~~~~~~~~~~~
> > >
> > > I think the message is somewhat misguided as all the
> > > vararg arguments have implicit integer promotions.
> >
> > That's a fair point, but Clang checks the arguments against their
> > format specifier before they're promoted when using -Wformat.
>
> Perhaps clang could be a bit more verbose if
> checking signed types emitted as unsigned or
> unsigned types emitted as signed instead.
It is a little strange that clang warns when the length specifier
doesn't match but not when an unsigned specifier is used for a signed
value and vice versa.
>
> > When
> > considering integer promotions it's difficult to say if this is
> > "wrong",
>
> I didn't write "wrong", I wrote misguided.
Apologies for my poor wording. I meant "wrong" in the sense that it's
unclear if an improper length specifier is deserving of a warning.
After all GCC doesn't warn for incorrect length specifiers, and as you
pointed out Clang doesn't pay attention to if the specifier expects a
signed or unsigned value.
Cheers,
Jon
next prev parent reply other threads:[~2019-03-01 0:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 11:52 [PATCH] wusb: use correct format characters Louis Taylor
2019-02-28 11:59 ` Greg KH
2019-02-28 12:24 ` [PATCH v2] " Louis Taylor
2019-02-28 19:19 ` Nick Desaulniers
2019-02-28 21:53 ` Joe Perches
2019-02-28 22:23 ` Jon Flatley
2019-02-28 23:05 ` Joe Perches
2019-03-01 0:03 ` Jon Flatley [this message]
2019-03-01 4:38 ` [PATCH] wusb: Remove unnecessary static function ckhdid_printf Joe Perches
2019-03-01 11:15 ` Louis Taylor
2019-03-01 18:18 ` Nick Desaulniers
2019-03-01 19:54 ` Greg KH
2019-03-05 16:21 ` [PATCH] wusb: use correct format characters Test
2019-03-05 16:28 ` Test
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CACJJ=pz50c3oovHbKkjDDF=pabAj_9RtKGWvtpwx4nO+E_EtJg@mail.gmail.com' \
--to=jflat@chromium.org \
--cc=clang-built-linux@googlegroups.com \
--cc=gregkh@linuxfoundation.org \
--cc=joe@perches.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=louis@kragniz.eu \
--cc=ndesaulniers@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).