Re: [RFC 0/2] Eliminate zero length arrays in DPDK

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Feb 16, 2022 at 11:05:09AM +0100, Morten Brørup wrote:
> > From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> > Sent: Wednesday, 16 February 2022 10.33
> > 
> > On Tue, Feb 15, 2022 at 03:00:56PM -0800, Stephen Hemminger wrote:
> > > Yet another case of applying Linux kernel best practices
> > > to DPDK. Flexible arrays are supported by Clang, GCC and
> > > Microsoft compilers (part of C99).
> > >
> > Do we need to start explicitly stating that DPDK uses C99 features, and
> > adding -std=c99 to our build flags? Are we also requiring that
> > applications
> > are compiled with c99 features to use this (I would hope that they are,
> > but
> > I'm not sure we can mandate it).
> 
> No to -std=c99. It's >= C99 for applications; we should not prevent them from using a newer C standard.

Yes. For build flags, I was referring only to having it in the cflags for the
build of DPDK itself, not for apps. We definitely need to minimise the
build flags we expose to apps.

> 
> Adding a note about the C standard version to the DPDK requirements
> documentation would be very nice. It only mentions a certain compiler
> version required. But I think that documenting the detailed build and
> runtime requirements (and why they are that way) is another task.
> 
Sure, we should do that. I am just wanting to be sure that if we specify a
minimum of C99, we won't get complaints back from those with legacy
codebasees which only support C89/C90. I am therefore wondering if we need
to have our public headers C90-compliant?

/Bruce