linux-kernel - Re: [PATCH] afs: use correct format characters

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Date:   Thu, 11 Apr 2019 09:31:33 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Joe Perches <joe@...ches.com>
Cc:     Louis Taylor <louis@...gniz.eu>,
        David Howells <dhowells@...hat.com>,
        linux-afs@...ts.infradead.org,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH] afs: use correct format characters

On Wed, Apr 10, 2019 at 4:01 PM Joe Perches <joe@...ches.com> wrote:
>
> I really think this clang message should be ignored.

Agreed.

> It's really unnecessary as every vararg argument smaller
> than int size is already promoted to int.

Exactly. It's a pointless warning, making for more complex code, and
making people remember esoteric printf format details that have no
reason for existing.

The "h" and "hh" things should never be used. The only reason for them
being used if if you have an "int", but you want to print it out as a
"char" (and honestly, that is a really bad reason, you'd be better off
just using a proper cast to make the code more obvious).

So if what you have a "char" (or unsigned char) you should always just
print it out as an "int", knowing that the compiler already did the
proper type conversion.

                             Linus