Re: Linux kernel headers

[Ryan Arnold <ryan dot arnold at gmail dot com>]

On Thu, Jul 2, 2009 at 6:49 AM, booleandomain<booleandomain@gmail.com> wrote:
> Hello,
>
> I have some doubts about the following configure options: --with-headers,
> --enable-kernel.
>
> First: does really glibc require linux kernel headers for a successful
> compilation? That is, can I specify something such as --without-headers?

Of course it does.  The kernel headers are a contract between GLIBC
and the Kernel about what facilities the Kernel provides.  For
instance, private futex support.  You can just leave all of this off
and GLIBC will use the kernel in the system default kernel header
location and it will also compile against the 'current' kernel version
that your system describes.

> Second: if I specify --with-headers=$PATH can I delete $PATH directory after a
> successful build?

Yes, headers are a build time requirement, not a runtime requirement.

> Third: can I specify --enable-kernel=2.6.30 even if my host os run version
> 2.6.29? or should I stick to 2.6?

Using plain old 2.6 is way too old.

You _may_ be able to get away with 2.6.30.  We try to make sure that
GLIBC doesn't use version specific facilities without asking the
kernel if they're available but you can't always query for every
feature.  It is guaranteed that if you specify 2.6.20 you won't get
any facilities provided by 2.6.29.  If you specify 2.6.30 your running
GLIBC may try to determine if the kernel on the system is really a
2.6.30 system before using a 2.6.29 facilitiy.

> Thanks.

I hope this helps.

Ryan S. Arnold