On Sun, Aug 4, 2024 at 10:05 AM Gina P. Banyard <[email protected]> wrote:
>
>
> On Friday, 2 August 2024 at 14:33, Giovanni Giacobbi <[email protected]> wrote:
>
> On Thu, 1 Aug 2024 at 23:57, Ilija Tovilo <[email protected]> wrote:
>>
>> [...]
>> I started fixing these in a PR [1] which required more changes than
>> expected. After a short discourse, we were wondering whether it might
>> be better to switch to a newer C standard instead. Our coding
>> standards [2] currently specify that compiling php-src requires C99.
>> The Unix installation page on php.net [3] claims it is ANSI C, which
>> is certainly outdated. There have been suggestions to require C11 for
>> a while, which should be well supported by all compilers shipped with
>> maintained distributions.
>
>
> It feels wrong to raise such an important requirement that might affect a lot of people,
> including maintainers of extensions, for just one specific problem, and 99% of the codebase would
> still be C99 compliant.
>
> I quickly put together an alternative PR (#15202) with a slightly different approach, just as a
> proof of concept. The idea is to move all the global typedefs in a new include header
> "zend_types_defs.h" (but also zend_portability.h can be reused for this purpose, as all
> the relevant files already include it).
>
> While putting together that PR, I had the feeling that this typedef redefinition problem is in
> reality hiding some smelly design of header files. So maybe, rather than requiring a compiler more
> tolerant to poor code, we should rather focus on getting the design right.
>
>
> I would like to see actual factual data rather than "vibes" as to how this would
> cause issues with third-party extensions.
> php-src is not C99 pedeantic compliant and we do use GCC extenstions.
>
> I do agree that maybe we should go back to fixing headers, but considering the drama this
> caused 18 months ago I do not know who here has the motivation to do this.
>
> Ideally I feel we should target C17 as it is a "bug fix" release of C11, but this
> might be impossible due to old compilers still being the default on LTS Distributions.
> The main benefit of C11/17 in the long run are atomics, that we kinda use already anyway.
As a person who wrote some of those atomics, I would definitely prefer
to move to standard C11/C17 atomics at some point in the future and
remove all other fallbacks. The blocker right now is Microsoft Visual
Studio. Although they added C11/C17 support a few versions back, they
did not add atomics at that time. It's available now, but it is still
experimental as far as I can tell.
Maybe for PHP 9.0 we can address header issues and also by then VS
will have a general release we can move to for atomics.
One thing I feel strongly about is that we should not add flags like
-std=c11. If we check, we ought to just ensure that whatever flags
the user provided, we have certain C11/C17 features. This allows for
extensions to use a newer version, or a relaxed version like
-std=gnu11.