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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: switch/extension for see below strongly needed
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cross@spitfire.i.gajendra.net (Dan Cross) writes:

> [...] An observation pointed out to me at my last gig, and that
> I now point out occasionally myself, is that Linux (for example)
> is not so much written in C but rather in Linux C, which is the
> dialect of the language defined by the compilers they use and
> the specific behaviors they force using flags, pragmas, etc, for
> those compilers.

Any program accepted by a conforming implementation is a C program.
That remains true even if the program relies on compiler options
such as -fwrap or -fno-strict-aliasing, or takes advantage of
specific behaviors chosen by the compiler in situations that the C
standard deems undefined behavior, or uses non-standard #pragmas
that the implementation has chosen to define.  As long as the
implementation stays inside the bounds of being conforming, any
program it accepts is written in C.  Writing in a subset of the full
language doesn't change that:  a C program that has no 'goto'
statements in it is still a C program.  The same reasoning applies
to programs that make use of -fwrapv, etc.

> At any rate, it's certainly not strictly
> conforming ISO C:  is _any_ large program strictly conforming at
> this point?  I suspect many projects strive for such, but few
> actually attain it.

I expect most people don't realize how high a bar it is to write a C
program that is strictly conforming.  Except for toy examples I
don't think I've ever seen one.  I wouldn't advocate choosing such a
criterion.  Even more than that, if a member of any team I was part
of did suggest doing so I would strongly argue against it.  Even if
it could be done, which I think is unlikely, the amount of effort
needed to do so would be prohibitive.