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

["Morten Brørup" <mb@smartsharesystems.com>]

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My answer is at the end.Sent from a smartphone. Please pardon brevity and spelling.
-------- Oprindelig besked --------Fra: Bruce Richardson <bruce.richardson@intel.com> Dato: 16/02/2022  11.15  (GMT+01:00) Til: Morten Brørup <mb@smartsharesystems.com> Cc: Stephen Hemminger <stephen@networkplumber.org>, dev@dpdk.org Emne: Re: [RFC 0/2] Eliminate zero length arrays in DPDK 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 thebuild of DPDK itself, not for apps. We definitely need to minimise thebuild 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 aminimum of C99, we won't get complaints back from those with legacycodebasees which only support C89/C90. I am therefore wondering if we needto have our public headers C90-compliant?/BruceWe are publicly using C11 for atomics [1]. I'm not sure if that also implies that we are requiring C11 generally.Otherwise,  I agree with your concerns about old code bases.[1]https://www.dpdk.org/blog/2021/03/26/dpdk-adopts-the-c11-memory-model/-Morten

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