René Ferdinand Rivera Morell wrote:

On Tue, Mar 26, 2024 at 7:29 AM Дмитрий Архипов via Boost wrote:

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Recently we stopped supporting C++03. Now, the only compilers which support C++11, but do not claim some support of C++14 (that I am aware of) are GCC versions 4.8 and 4.9. But even C++11 support in those GCC versions is fairly buggy and those who still test on them often have to resort to various tricks to make their code build. Those compilers are fairly old, and the systems that use them increasingly go extinct. This makes me consider removing them from CI. Which is why I want to ask the community several questions:

1) Do you still use GCC 4.8 or 4.9? 2) If you do, is there a specific date when you plan to drop them? 2) Do you use some other compiler which supports C++11, but not C++14 (even with flags like -std=c++1y)?

The first two questions from https://www.jetbrains.com/lp/devecosystem-2023/cpp/ should answer your questions.

They don't, as it's still possible to use C++11 with GCC 5 and above. In this specific case Boost.Charconv supports C++11, but GCC 5 and above, whereas Boost.JSON supports GCC 4.8 and 4.9. So it's not possible to use Charconv from JSON unless support for 4.x (but not necessarily C++11) is dropped.

On 3/26/24 15:46, Peter Dimov via Boost wrote:

René Ferdinand Rivera Morell wrote:

...

On Tue, Mar 26, 2024 at 7:29 AM Дмитрий Архипов via Boost wrote:

...

Recently we stopped supporting C++03. Now, the only compilers which support C++11, but do not claim some support of C++14 (that I am aware of) are GCC versions 4.8 and 4.9. But even C++11 support in those GCC versions is fairly buggy and those who still test on them often have to resort to various tricks to make their code build. Those compilers are fairly old, and the systems that use them increasingly go extinct. This makes me consider removing them from CI. Which is why I want to ask the community several questions:

1) Do you still use GCC 4.8 or 4.9? 2) If you do, is there a specific date when you plan to drop them? 2) Do you use some other compiler which supports C++11, but not C++14 (even with flags like -std=c++1y)?

The first two questions from https://www.jetbrains.com/lp/devecosystem-2023/cpp/ should answer your questions.

They don't, as it's still possible to use C++11 with GCC 5 and above.

In this specific case Boost.Charconv supports C++11, but GCC 5 and above, whereas Boost.JSON supports GCC 4.8 and 4.9. So it's not possible to use Charconv from JSON unless support for 4.x (but not necessarily C++11) is dropped.

My understanding of the original post is that dropping C++11 is what's desired, and dropping the older compilers is a side effect of that. Hence the third question.

On Tue, Mar 26, 2024 at 5:56 AM Andrey Semashev via Boost < boost@lists.boost.org> wrote:

My understanding of the original post is that dropping C++11 is what's desired

With respect to the libraries I have written, that's going a bit too far for my taste. Arbitrarily dropping C++11 does not sound like a great idea. If requiring at least C++14 offers a significant improvement in some aspect of a library (for example Boost.JSON) then the specifics of that improvement should be discussed and the cost/benefits analyzed. Thanks

However my tolerance for GCC 4.x with respect to incomplete or defective support for C++11 is non-existent. I will support those versions as long as doing so does not require heroics or an inordinate amount of my time.

The original question stems from: https://github.com/boostorg/charconv/issues/174. I have the exact same opinion of GCC 4.X which is why it is not supported in charconv. Dropping support for GCC 4.X in JSON to allow for the use of charconv yields substantial performance improvements: https://github.com/boostorg/json/pull/993. Matt