Re: [patch 1/8] extend make headers_check to detect more problems

[David Woodhouse <dwmw2@infradead.org>]

On Mon, 2006-09-18 at 03:27 +0200, Arnd Bergmann wrote:
> plain text document attachment (headercheck-base.diff)
> In addition to the problem of including non-existant header
> files, a number of other things can go wrong with header
> files exported to user space. This adds checks for some
> common problems:
> 
> - The header fails to include the files it needs, which
>   results in build errors when a program tries to include
>   it. Check this by doing a dummy compile.
> 
> - There is a declarations of a static variable or non-inline
>   function in the header, which results in object code
>   in every file including it. Check for symbols in the object
>   with 'nm'.
> 
> - Part of the header is subject to conditional compilation
>   based on CONFIG_*. Add a regex search for this.

It would be good to fix these problems, it's true -- but bear in mind
that none of these are actually fatal problems -- they're just caveats
of (ab)using kernel-private headers in userspace. 

On the other hand, it would be good to get people used to running
'make headers_check' whenever they make a change -- so introducing more
breakage right now may be counterproductive from that point of view.

So I think I'd prefer to leave this for now, or at least limit it to
'make CHECKMEHARDER=1 headers_check' so that we can wean people onto
using headers_check slowly and relatively painlessly.

> I found many problems with this, which I then fixed for
> powerpc, s390 and i386, in subsequent patches.

Can you -include <linux/types.h> _every_ time, to reduce the number of
places you have to add '/* @headercheck: -include linux/types.h @ */' ?

-- 
dwmw2