svn commit: r325954 - in head: . share/mk sys/conf usr.sbin/config

[Bruce Evans]

On Sat, 18 Nov 2017, Warner Losh wrote:

> On Sat, Nov 18, 2017 at 3:42 AM, Bruce Evans <brde at optusnet.com.au> wrote:
>
>> since it flags all c99 and newer usages as syntax errors. We've been
>>>>>
>>>>
>> This shouldn't break use of lint on K&R or C90 sources.  But types.h is
>> broken.  It no longer supports K&R, C90, or most other things that are
>> supposed to be controlled by the visibility ifdefs in it.
>
> Thanks for this insightful analysis. I've clipped the rest of it, which is
> more of the same. It can't support the new C compiler construct, and we've
> managed to break the old ones. Plus it gives lots of warnings that aren't

Lint is just the messenger (until its annotations like NOTREACHED are also
removed).  It can support old C compiler constructs like it used to,
including pre-standard ones that new C compilers/checks might not support.

> useful and doesn't understand several of the idioms we've started using
> heavily in the kernel (such as forward struct declaration). Since many of
> these problems are in the system kernel headers, the break all non-trivial
> uses of lint.
>
> None of these things are ever going to be fixed. It's quite likely the

We are never going to fix feature test macros like _POSIX_SOURCE?  Then
removing support for them would give much simpler sources.

> kernel will never again compile on anything older than a c99 compiler.
> While we have a lot of ifdefs to attempt to support older compilers, it's
> almost all certainly bit-rotted from lack of use.

The headers and libraries (non-source parts) should not be limited by the
language used to compile the kernel.  Pascal is not supported, but old
variants of C require only a small amount of code relative to new variants,
so should remain supported.

Kernels don't actually compile with a C99 compiler.  They need -std=gnu99
plus lots of underscores to use extensions.  The kernel is misconfigured
with -std=isomumble:1999 -fms-extensions and only compiles because this
doesn't give strict C99 (+ ms extensions but no gnu extensions).  Userland
is configured correctly with -std=gnu99.

Bruce