linux-kernel - Re: [PATCH] docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]

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Date:   Fri, 6 Sep 2019 22:37:29 +0100
From:   Louis Taylor <louis@...gniz.eu>
To:     Joe Perches <joe@...ches.com>
Cc:     linux-doc@...r.kernel.org, corbet@....net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] docs: printk-formats: Stop encouraging use of
 unnecessary %h[xudi] and %hh[xudi]

On Fri, Sep 06, 2019 at 02:11:51PM -0700, Joe Perches wrote:
> Standard integer promotion is already done and %hx and %hhx is useless
> so do not encourage the use of %hh[xudi] or %h[xudi].
> 
> As Linus said in:
> Link: https://lore.kernel.org/lkml/CAHk-=wgoxnmsj8GEVFJSvTwdnWm8wVJthefNk2n6+4TC=20e0Q@mail.gmail.com/
> 
> 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.

Yeah, makes sense. Sorry for adding these in the first place.

Reviewed-by: Louis Taylor <louis@...gniz.eu>