linux-kernel - Re: Mark bitrevX() functions as const

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Date:	Mon, 11 Dec 2006 16:12:52 +0000
From:	David Howells <dhowells@...hat.com>
To:	Linus Torvalds <torvalds@...l.org>
Cc:	David Howells <dhowells@...hat.com>,
	Akinobu Mita <akinobu.mita@...il.com>, akpm@...l.org,
	linux-kernel@...r.kernel.org
Subject: Re: Mark bitrevX() functions as const 

Linus Torvalds <torvalds@...l.org> wrote:

> > Mark the bit reversal functions as being const as they always return the
> > same output for any given input.
> 
> Well, we should mark the argument const too, no?

The argument is just an integer; I'm not sure that marking it const actually
achieves anything, except to tell the function that it can't modify it - and
since it's effectively a copy, where's the fun in that.

> Does anythign actually improve from this? Also, we should actually use 
> "__attribute_const__" instead (which works with other compilers), not the 
> gcc'ism. That "__attribute__((const))" thing is a horrible syntax anyway 
> (and has apparently slipped into <linux/log2.h> too - Damn.

Ah.  I thought that was just for supporting old versions of gcc.  I didn't
realise it was for handling strange compilers.

David
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