Re: [DISCUSS] Update backend c++ standard to gnu20

[Yuxuan Cheng]

Looking forward to upgrading to c++20, then we can use atomic<shared_ptr>.

BiteTheDDDDt <pxl...@qq.com.invalid> 于2022年7月22日周五 20:22写道：

> Hi All,
> &nbsp; The community recently added ci detection for clang build, which
> can avoid build failures caused by some differences
>
> between gcc and clang. I think now we can start talking again about
> whether we should upgrade the C++ standard
>
> from gnu++17 to gnu++20.
>
> &nbsp;
> Over&nbsp;the&nbsp;past&nbsp;few&nbsp;months,&nbsp;some&nbsp;work&nbsp;has&nbsp;been&nbsp;becoming&nbsp;a&nbsp;natural&nbsp;progression.&nbsp;In&nbsp;the&nbsp;past,&nbsp;we&nbsp;needed&nbsp;to&nbsp;patch&nbsp;phmap
>
>
> and&nbsp;introduce&nbsp;the&nbsp;absl&nbsp;library&nbsp;as&nbsp;a&nbsp;dependency.&nbsp;Now&nbsp;the&nbsp;new&nbsp;version&nbsp;of&nbsp;phmap&nbsp;is&nbsp;released&nbsp;to&nbsp;fix&nbsp;its&nbsp;incompatibility&nbsp;with&nbsp;C++20,
>
>
>
> and&nbsp;the&nbsp;dependence&nbsp;on&nbsp;absl&nbsp;can&nbsp;also&nbsp;help&nbsp;us&nbsp;to&nbsp;upgrade&nbsp;the&nbsp;version&nbsp;of&nbsp;tcmalloc.
>
>
>
> ------------------&nbsp;原始邮件&nbsp;------------------
> 发件人:
>                                                   "BiteTheDDDDt"
>                                                                         <
> pxl...@qq.com&gt;;
> 发送时间:&nbsp;2022年5月9日(星期一) 下午5:16
> 收件人:&nbsp;"dev"<dev@doris.apache.org&gt;;
>
> 主题:&nbsp;回复： [DISCUSS] Update backend c++ standard to gnu20
>
>
>
> Maybe we can just use the feature just both gcc and clang supported until
> we decide to use gcc or clang.I think there won't be a lot of code
> involving new features of the C++20 standard, so it's rare to meet
> compatibility problems.
>
>
>
>
>
> ------------------ 原始邮件 ------------------
> 发件人:
>                                                   "dev"
>                                                                 <
> yangz...@gmail.com&gt;;
> 发送时间:&nbsp;2022年5月9日(星期一) 下午4:56
> 收件人:&nbsp;"dev"<dev@doris.apache.org&gt;;
>
> 主题:&nbsp;Re: [DISCUSS] Update backend c++ standard to gnu20
>
>
>
> I checked the support of gcc[1] and clang[2] for the cxx20 standard, gcc
> can partially support it, but the support of clang is poor. If it is
> upgraded, how to ensure the compatibility of the code under gcc and clang
>
> [1] https://gcc.gnu.org/projects/cxx-status.html#cxx20
> [2] https://clang.llvm.org/cxx_status.html#cxx20
> Thanks
> Yang Zhengguo
>
>
> BiteTheDDDDt <pxl...@qq.com.invalid&gt; 于2022年5月9日周一 15:54写道：
>
> &gt; Hello&amp;nbsp;everyone:
> &gt; I want to update our c++ standard from gnu17 to gnu20, then we can use
> &gt; some new feature such as `concept`,`coroutines`,`template lambda
> function`.
> &gt; Currently our code doesn't need much modification to adapt to the
> c++20
> &gt; standard, this is my pull-request
> &gt; https://github.com/apache/incubator-doris/pull/9313.
> &gt; welcome to discuss this.