On Wed, 25 Mar 2020 at 19:10, Peter Dimov via Boost wrote:

Mateusz Loskot wrote:

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Are there any recommendations or requirements on how we should proceed?

Yes, https://pdimov.github.io/articles/phasing_out_cxx03.html#_suggested_policy

Excellent, thanks! I see that I missed it in the archive of the not-so-distant past https://lists.boost.org/Archives/boost/2019/11/247290.php Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

On Thu, 26 Mar 2020 at 02:50, Alexander Grund via Boost < boost@lists.boost.org> wrote:

Hi,

as Boost.Nowide is now release ready and will be included in the 1.73 release I wanted to announce that I'm planning to require C++11 for anything after.

Is there support for C++17 <filesystem>? There are a few minor things which need different other libs of Boost

for C++98 support and given the age of C++11 support in especially MS compilers I want to reduce the dependencies to (almost) nothing. I say "MS compilers" because this is a Windows-centric lib and will most likely most often be used with MSVC.

However I'll evaluate supporting even some older MSVC versions making some C++11 features optional if possible.

Don't do that.

Best Regards, Alexander Grund

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On Thu, 26 Mar 2020 at 11:38, Alexander Grund via Boost wrote:

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However I'll evaluate supporting even some older MSVC versions making some C++11 features optional if possible.

Don't do that.

Ok, then I have to require MSVC 2015 which is fine to me. How would I tell the test matrix about this?

By specifying cxx11 features as required in test/Jamfile For example: https://github.com/boostorg/mp11/blob/develop/test/Jamfile#L15 https://github.com/boostorg/gil/blob/develop/test/Jamfile#L57-L63 Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

On Thu, 26 Mar 2020 at 11:54, Alexander Grund via Boost wrote:

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Ok, then I have to require MSVC 2015 which is fine to me. How would I tell the test matrix about this? By specifying cxx11 features as required in test/Jamfile

For example: https://github.com/boostorg/mp11/blob/develop/test/Jamfile#L15 https://github.com/boostorg/gil/blob/develop/test/Jamfile#L57-L63

The feature I require does not yet exist. I need movable std streams which MSVC supports since 2015 but 2013 does support most (many) C++11 features already.

Listing any cxx_* features which are not supported by VS 2013 should allow to filter 2013 and let the matix skip the builds. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

On Thu, 26 Mar 2020 at 13:02, Mike via Boost wrote:

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Gesendet: Donnerstag, 26. März 2020 um 12:25 Uhr Von: "Mateusz Loskot via Boost"

On Thu, 26 Mar 2020 at 11:54, Alexander Grund via Boost wrote:

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Ok, then I have to require MSVC 2015 which is fine to me. How would I tell the test matrix about this? By specifying cxx11 features as required in test/Jamfile

For example: https://github.com/boostorg/mp11/blob/develop/test/Jamfile#L15 https://github.com/boostorg/gil/blob/develop/test/Jamfile#L57-L63

The feature I require does not yet exist. I need movable std streams which MSVC supports since 2015 but 2013 does support most (many) C++11 features already.

Listing any cxx_* features which are not supported by VS 2013 should allow to filter 2013 and let the matix skip the builds.

That seems excessively indirect. Isn't it possible to just say "if msvc, requires msvc > 14.0" ?

Certainly, a compiler-specific filtering can be scripted in Boost.Jam. Here is a possible solution project : requirements <conditional>@disable-old-compiler ; rule disable-old-compiler ( properties * ) { local result ; if <toolset>msvc in $(properties) { # MSVC++ 12.0 (Visual Studio 2013) if toolset-msvc:version12.0 in $(properties) { echo ****** This MSVC++ version is too old ****** ; result = <build>no ; } } # else if for other oldies return $(result) ; } My Boost.jam fu is very limited, so there likely is a better solution. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

W dniu 26.03.2020 o 11:45, Mateusz Loskot via Boost pisze:

On Thu, 26 Mar 2020 at 11:38, Alexander Grund via Boost wrote:

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How would I tell the test matrix about this? By specifying cxx11 features as required in test/Jamfile

For example: https://github.com/boostorg/mp11/blob/develop/test/Jamfile#L15 https://github.com/boostorg/gil/blob/develop/test/Jamfile#L57-L63 Currently to check the standard support we have to use several macros or write our own check based on compiler version. Now more libraries are switching to the newer standard I think a set of macros defining full support for a standard would be useful so an author could check one macro as a base requirement for a library and from that point enable additional features conditionally. So what do you think about adding e.g. BOOST_CXX11, BOOST_CXX14, etc. to Boost.Config? Or in negated form: BOOST_NO_CXX11, BOOST_CXX14, etc. which we all learned to love. ;)

Adam

On Thu, 26 Mar 2020 at 12:27, Adam Wulkiewicz via Boost wrote:

W dniu 26.03.2020 o 11:45, Mateusz Loskot via Boost pisze:

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On Thu, 26 Mar 2020 at 11:38, Alexander Grund via Boost wrote:

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How would I tell the test matrix about this? By specifying cxx11 features as required in test/Jamfile

For example: https://github.com/boostorg/mp11/blob/develop/test/Jamfile#L15 https://github.com/boostorg/gil/blob/develop/test/Jamfile#L57-L63

Currently to check the standard support we have to use several macros or write our own check based on compiler version. Now more libraries are switching to the newer standard I think a set of macros defining full support for a standard would be useful so an author could check one macro as a base requirement for a library and from that point enable additional features conditionally. So what do you think about adding e.g. BOOST_CXX11, BOOST_CXX14, etc. to Boost.Config? Or in negated form: BOOST_NO_CXX11, BOOST_CXX14, etc. which we all learned to love. ;)

The macros are useful but only if you want to support multiple C++ versions simultaneously, 03 and 11, etc. In such case you rather want a feature-specific macro anyway, as it is also self-documenting and makes clear what kind of workaround you apply. The config checks are b2 mechanism. For Jamfile, an all-in-one check would be useful indeed e.g. [ requires cxx11 ] Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

Alexander Grund wrote:

There are a few minor things which need different other libs of Boost for C++98 support and given the age of C++11 support in especially MS compilers I want to reduce the dependencies to (almost) nothing. I say "MS compilers" because this is a Windows-centric lib and will most likely most often be used with MSVC.

"C++11" doesn't have any sensible meaning for MS compilers so you'll have to specify a version.