Re: /usr/include/linux and stuff

[Alastair Donlon <nospam [at] netsoc.ucd.ie>]

On Thu, Feb 17, 2000 at 02:16:25PM +0900, Stephen J. Turnbull wrote:
> >>>>> "Al" == Al Hudson <eah106 [at] york.ac.uk> writes:
> 
>     Al> On Wed, 16 Feb 2000, Stephen J. Turnbull wrote:
> 
>     Al> Kernel includes shouldn't be included in user-land
>     Al> compilation. Simple as that?!
> 
> Oh.  Then it's not glibc's fault.  Case closed?
> 
>     Al> Once glibc is compiled, the headers should match the
>     Al> library. It also makes it a complete arse if you i) retarget
>     Al> compilers, ii) have multiple glibc/libc, iii) have multiple
>     Al> kernel source trees.
> 
> Agreed.  So what?  You can't solve this problem without (a) freezing
> the kernel headers permanently (Linus won't find that acceptable ;) or
> (b) tightly coupling glibc with the kernel the way (eg) modules and
> (better eg) pcmcia-cs's cardmgr is (at least under Debian).  Users
> won't find that acceptable, I suspect.
> 

It's not _quite_ that bad. The problem with libc5's way of doing
things was that every time the kernel changed an internal
data structure, libc5 was potentially screwed. So, all the
kernel only data structures were wrapped with 

#ifdef __KERNEL__ ... #endif

Linus never really liked this, 'cos it messes with the neatness
of header files, but he had little choice unless libc5 was to
be tightly coupled to the kernel headers, like modules etc.
So, the movement for glibc grew - kernel people would maintain
the kernel headers and glibc people would maintain their own
set of 'kernel interface' headers.

Glibc then only really needs to be changed if the kernel alters
its own interface (mostly through the system calls). In theory,
if the interface to the kernel changes, then it should be released
as a new major number and all bets are off anyway ;)

A.D.
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