linux-kernel - CodingStyle question: multiple statements on a single line

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Message-Id: <200809030021.00122.hverkuil@xs4all.nl>
Date:	Wed, 3 Sep 2008 00:20:59 +0200
From:	Hans Verkuil <hverkuil@...all.nl>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	"v4l-dvb maintainer list" <v4l-dvb-maintainer@...uxtv.org>
Subject: CodingStyle question: multiple statements on a single line

Hi all,

On the v4l-dvb list there has been confusion on how to interpret the 
following in the CodingStyle document:

"Don't put multiple statements on a single line unless you have 
something to hide:

        if (condition) do_this;
          do_something_everytime;

Don't put multiple assignments on a single line either.  Kernel coding 
style is super simple.  Avoid tricky expressions."

Does this mean:

1) Yes, after an 'if' you can put a single statement like this:

	if (a) b;

2) No, never use the 'if (a) b;' construction. Put 'b;' on the next line 
instead.

It's the 'have something to hide' part that confuses people: is this 
literal or is this sarcastic? This should be reworded to whatever is 
really meant.

And in general, why is this:

if (a) {
	b;
}

not accepted by the CodingStyle? (At least as I understand it)

Many people find this more readable and certainly safer. Certainly in 
cases like this:

for (...)
	for (...)
		statement;

I would really prefer to have curly brackets as that is much clearer. I 
would suggest that having curly brackets around a single statement is 
made optional. Especially in view of the sentence 'Avoid tricky 
expressions' I would say that this:

if (a)
	b;

is definitely trickier than:

if (a) {
	b;
}

All it takes is a single indentation error to get into trouble here.

Regards,

	Hans
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