just how "sanitized" are the sanitized headers?

just how "sanitized" are the sanitized headers?

[Robert P. J. Day]

  i noticed that, when i generate the sanitized headers with "make
headers_install", there are still a number of headers files that are
installed with variations on "#ifdef __KERNEL__".

  i always thought the fundamental property of sanitized headers was
to be compatible with glibc and have no traces of "KERNEL" content
left.  so what's the purpose of leaving some header files with that
preprocessor content?  thanks.

rday

Re: just how "sanitized" are the sanitized headers?

[Alexey Dobriyan]

On 11/30/06, Robert P. J. Day <rpjday@mindspring.com> wrote:
>   i noticed that, when i generate the sanitized headers with "make
> headers_install", there are still a number of headers files that are
> installed with variations on "#ifdef __KERNEL__".
>
>   i always thought the fundamental property of sanitized headers was
> to be compatible with glibc

You were wrong.

> and have no traces of "KERNEL" content
> left.

That's correct.

> so what's the purpose of leaving some header files with that
> preprocessor content?

When you see __KERNEL__ in sanitized headers, it's either due to
a) unifdef bug, or
b) header being listed in header-y when it should be listed in unifdef-y

Re: just how "sanitized" are the sanitized headers?

[Robert P. J. Day]

On Thu, 30 Nov 2006, Alexey Dobriyan wrote:

> On 11/30/06, Robert P. J. Day <rpjday@mindspring.com> wrote:
> >   i noticed that, when i generate the sanitized headers with "make
> > headers_install", there are still a number of headers files that are
> > installed with variations on "#ifdef __KERNEL__".
> >
> >   i always thought the fundamental property of sanitized headers was
> > to be compatible with glibc
>
> You were wrong.

ok, my fault, i worded that badly.  i have a *general* idea of the
purpose of sanitized headers -- i've been using a pre-built set for
crosstool for quite some time, and i'm assuming that (theoretically) i
should be able to replace that pre-built set with what's generated by
"make headers_install", is that right?

(BTW, what is the proper description for the sanitized headers?
there's *nothing* in the kernel source tree documentation that
explains their creation.)

> > and have no traces of "KERNEL" content
> > left.
>
> That's correct.

good.  at least *that* part i got right. :-)

> > so what's the purpose of leaving some header files with that
> > preprocessor content?
>
> When you see __KERNEL__ in sanitized headers, it's either due to
> a) unifdef bug, or
> b) header being listed in header-y when it should be listed in unifdef-y

a couple things going on here, actually.  in the simple case, there
are three header files:

  linux/if_fddi.h
  linux/personality.h
  linux/wireless.h

that can be fixed simply by adding "unifdef-y" entries for them to the
Kbuild file (i can submit a patch shortly).  but there are a few other
cases which still contain compound preprocessor directives such as:

  #if defined(__KERNEL__) || !defined(__GLIBC__) || (__GLIBC__ < 2)

having never worked with unifdef before, i guess i was being overly
optimistic in thinking that it, if i "unifdef"ed __KERNEL__, it might
at least simplify the expression.  oh, well ... live and learn.

rday