Re: [PATCH 1/4] tools/nolibc: evaluate syscall() arguments before the arch macros

[Willy Tarreau <w@1wt.eu>]

On Mon, Jul 27, 2026 at 08:21:45AM +0700, Ammar Faizi wrote:
> On Mon, Jul 27, 2026 at 3:16 AM Thomas Weißschuh wrote:
> > __auto_type is only supported from GCC 4.9. I think this is old enough,
> > but it should be mentioned at least.
> > We really should have a documented policy for that.
> 
> I suggest using the Linux kernel's minimal requirements. It's GCC 8.1
> or Clang 17.0.1. Ref: https://docs.kernel.org/process/changes.html
> 
> What do you think?

Since it's userland (i.e. not building with the kernel's compiler), and
often used for ease of porting boot-time tools in headless or embedded
environments, I'd really like that we keep compatibility for as long as
possible with oldest compilers that continue to work. Last time I checked,
it was still working fine with gcc-4.4. I still have my 4.7.4-based
toolchains that I regularly use for troublehooting and compatibility
checks (and faster builds), I can recheck. We should not require that to
be verified by contributors (too painful), however, noting "still known
to build fine with version X" is helpful. And the day we discover that
this promise has been broken for a year or so, we know we can safely
update it. I can recheck ASAP.

> Should this be documented in nolibc.h as a comment?

It can indeed be sufficient to add a line to the first comment block.
However I'm thinking that we would benefit from adding a larger README
in the sub-dir for contributors that explains some of the traps we often
have to mention.

thanks,
Willy