On Fri, Feb 10, 2023 at 09:52:06AM -0500, Ben Magistro wrote: > Adding Tyler > > Sort of following along on the RFC: introduce atomics [1] it seems like the > decision to use 99 vs 11 here could make an impact on the approach taken in > that thread.
hey Ben thanks for keeping an eye across threads on the topic. the atomics thread is fairly long but somewhere in it i did provide a rationale for why we can't just go straight to using C11 even if we declared that dpdk on supports compilers >= C11. i wish we could it would certainly make my life way easier if i could just -std=c11 and cut & paste my way to completion. the reason why we can't (aside from not requiring C11 compiler as a minimum) is that there is potential issue with abi compatibility for existing applications using non-atomic types currently passed to ABI suddenly requiring standard atomic types. this is because _Atomic type and type are not guaranteed to have the same size, alignment, representation etc.. anyway, i welcome us establishing c99 as a minimum for all toolchain/platform combinations. > > 1) http://mails.dpdk.org/archives/dev/2023-February/262042.html > > On Fri, Feb 3, 2023 at 1:00 PM Bruce Richardson <bruce.richard...@intel.com> > wrote: > > > On Fri, Feb 03, 2023 at 11:45:04AM -0500, Ben Magistro wrote: > > > In our case we have other libraries that we are using that have > > > required us to specify a minimum c++ version (14/17 most recently for > > > one) so it doesn't feel like a big ask/issue to us (provided things > > > don't start conflicting...hah; not anticipating any issue). Our > > > software is also used internally so we have a fair bit of control over > > > how fast we can adopt changes. > > > This got me wondering what some other projects in the DPDK ecosystem > > > are saying/doing around language standards/gcc versions. So some > > quick > > > checking of the projects I am aware of/looked at/using... > > > * trex: cannot find an obvious minimum gcc requirement > > > * tldk: we are running our own public folk with several fixes, need to > > > find time to solve the build sys change aspect to continue providing > > > patches upstream; I know I have hit some places where it was easier to > > > say the new minimum DPDK version is x at which point you just adopt > > the > > > minimum requirements of DPDK > > > * ovs: looks to be comfortable with an older gcc still > > > * seastar: seems to be the most aggressive with adopting language > > > standards/compilers I've seen [1] and are asking for gcc 9+ and cpp17+ > > > * ans: based on release 19.02 (2019), they are on gcc >= 5.4 [2] and > > is > > > the same on the main README file > > > I do understand the concern, but if no one is voicing an > > > opinion/objection does that mean they agree with/will not be affected > > > by the change.... > > > 1) [1]https://docs.seastar.io/master/md_compatibility.html > > > 2) [2]https://github.com/ansyun/dpdk-ans/releases > > > Cheers > > > > > Thanks for the info. > > I also notice that since gcc 5, the default language version used - if none > > is explicitly specified - is gnu11 (or higher for later versions). Clang > > seems to do something similar, but not sure at what point it started > > defaulting to a standard >=c11. > > > > /Bruce > >
