Date: Tue, 21 Feb 2006 16:18:57 -0800 (PST)
From: "Randy.Dunlap" <rdunlap@xenotime.net>
To: Herbert Poetzl <herbert@13thfloor.at>
cc: Sam Ravnborg <sam@ravnborg.org>, Daniel Barkalow <barkalow@iabervon.org>,
       Linux Kernel ML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] duplicate #include check for build system
In-Reply-To: <20060222001153.GF20204@MAIL.13thfloor.at>
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On Wed, 22 Feb 2006, Herbert Poetzl wrote:

> On Tue, Feb 21, 2006 at 06:52:46PM +0100, Sam Ravnborg wrote:
> > On Tue, Feb 21, 2006 at 02:29:12AM -0500, Daniel Barkalow wrote:
> > > On Tue, 21 Feb 2006, Herbert Poetzl wrote:
> >
> > > I think the kernel style is to encourage duplicate includes, rather than
> > > removing them. Removing duplicate includes won't remove any dependancies
> > > (since the includes that they duplicate will remain).
>
> > The style as I have understood it is that each .h file in include/linux/
> > are supposed to be self-contained. So it includes what is needs, and the
> > 'what it needs' are kept small.
> >
> > Keeping the 'what it needs' part small is a challenge resulting in
> > smaller .h files. But also a good way to keep related things together.
>
> glad that I stimulated a philosophical discussion
> about the kernel header files and what they should
> include or not ...
>
> but the idea was more to give the developers an
> instrument to verify that they are not including
> stuff several times, and that's actually in .h
> and .c files, because it seems that often the same
> header file is included twice in the _same_ file
>
> anyway, was this a positive or negative reply?

Hi Herbert,

The goal is not to remove the most possible #includes.

E.g., if sched.h already sucks in kernel.h,
kernel.h still should be #included if the source (.c)
files uses any APIs or extern data from kernel.h.

Does that help?

-- 
~Randy
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