netdev - RE: Coding Style: Reverse XMAS tree declarations ?

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Date:   Mon, 7 Nov 2016 11:00:49 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Lino Sanfilippo' <LinoSanfilippo@....de>,
        Joe Perches <joe@...ches.com>,
        David Miller <davem@...emloft.net>,
        "lsanfil@...vell.com" <lsanfil@...vell.com>
CC:     "madalin.bucur@....com" <madalin.bucur@....com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "corbet@....net" <corbet@....net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "oss@...error.net" <oss@...error.net>,
        "ppc@...dchasers.com" <ppc@...dchasers.com>,
        "pebolle@...cali.nl" <pebolle@...cali.nl>,
        "joakim.tjernlund@...nsmode.se" <joakim.tjernlund@...nsmode.se>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: RE: Coding Style: Reverse XMAS tree declarations ?

From: Lino Sanfilippo
> Sent: 04 November 2016 20:07
...
> In this case it is IMHO rather the declaration + initialization that makes
> "bar" hard to find at one glance, not the use of RXT. You could do something like
> 
>  	[longish list of reverse xmas tree identifiers...]
>  	struct foobarbaz *qux;
>  	struct foo *bar;
> 
>  	bar = longish_function(args, ...);
> 
> to increase readability.
> 
> Personally I find it more readable to always use a separate line for initializations
> by means of functions (regardless of whether the RXT scheme is used or not).

I find it best to only use initialisers for 'variables' that are (mostly) constant.
If something need to be set to NULL in case a search fails, set it to NULL
just before the loop.
Don't put initialisation on the declaration 'because you can'.

Difficulty in spotting the type of a variable is why (IMHO) you should
but all declarations at the top of a function
(except, maybe, temporaries needed for a few lines).

	David