[lfs-support] Headers in the system's include directory. Still Confused.

alupu at verizon.net alupu at verizon.net
Fri Feb 24 16:27:24 PST 2012


Hi Andy & Bruce,

Many thanks for your prompt, clear and helpful answers.

Andy:
> You should leave the kernel headers in /usr/include
> as they were when you installed glibc.

Bruce:
> The kernel varies, but you build glibc against one specific kernel.
> The programs that are built later need to be consistent with that 
> glibc/kernel header combination.

> Americans and British are separated by a common language.

The clarity and power of the subject Warning speaks volumes as to
what can result from a close British-American co-operation.

------------------------------------------------------------------

At the very least, your answers have helped me sharpen
my big question which, after all, is based on this actual,
immovable fact:

'udev-181' expects to find in '/usr/include/linux' a file,
'input.h', which contains the definition of a so called
BTN_TRIGGER_HAPPY.  Good, OK.  I understand.

Another secondary fact (which is most likely on me),
my current '/usr/include/linux/input.h' does NOT contain it.
Maybe because file too old, a mistake/omission in 6.7, etc., etc.
Bad, Not-OK.

------

Now I can crystallize my "header" question a lot more.

We know an 'udev-xxx' (say, 'udev-173') did not need
BTN_TRIGGER_HAPPY, while a later udev (say, 'udev-181')
aware of a _newer_ 'input.h' file floating around,
which does contain BTN_TRIGGER_HAPPY, expected the user
(i.e., me) to have this file in '/usr/include/...'.

Based on that, here's (finally) the finalized question:

IF I'm up to date with the LFS book, and am at
the latest Glibc, v2.14.1 (issued 07-Oct-2011, FWIW)
no matter what kernel version was at the time (say, 3.0.9)
- assuming I compiled Glibc-2.14.1 in Nov. 2011 -
 the "sanitized" headers installed as per Book 6.7
provide a guaranty for me that they contain the "correct" 'input.h'
 for as long as I stay with Glibc-2.14.1, no matter what
the udev version du jour (181++) might be.

Or put another way around, udev-173++ developers rely on
and expect me to have the Nov. 2011 headers (sanitised:)
and as for me, I'll be fine for any future udev release,
as long as the Glibc stays at 2.14.1.

Is that so?

BTW, I didn't know that developers (udev and otherwise) are
continuously careful to stay within the latest Glibc-thenKernel confines.

Thanks,
-- Alex

PS - I don't have any idea when BTN_TRIGGER_HAPPY made its
way into 'input.h'.  Too bad.  It'd've been interesting.



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