[R-pkg-devel] r-oldrel-linux- not in CRAN checks?

[Ivan Krylov]

В Tue, 6 Feb 2024 18:27:32 +0100
Vincent van Hees <vincentvanhees using gmail.com> пишет:

> For details see:
> https://github.com/RfastOfficial/Rfast/issues/99

GitHub processed your plain text description of the problem as if it
was Markdown and among other things ate the text that used to be there
between angle brackets:

>     #include
>              ^~~~~~~~~~~

By digging through the raw source code of the issue at
https://api.github.com/repos/RfastOfficial/Rfast/issues/99 it is
possible to find out which header was missing for Rfast:

> ../inst/include/Rfast/parallel.h:20:10:fatal error: tion: No such
> file or directory
>     #include <execution>
>              ^~~~~~~~~~~
>    compilation terminated.

Indeed, <execution> is a C++17 header [1]. While g++ version
7.5.0-3ubuntu1~18.04 seems to accept --std=c++17 without complaint, its
libstdc++-7-dev package is missing this header. Moreover, there's still
no <execution> in libstdc++-8-dev. I think that you need libstdc++-9
for that to work, which is not in Bionic; older versions aren't
C++17-compliant enough to compile Rfast, and C++17 is listed in the
SystemRequirements of the package.

Installing clang-10 and editing Makeconf to use clang++-10 instead of
g++ seems to let the compilation proceed. In order to successfully link
the resulting shared object, I also had to edit Makeconf to specify
-L/usr/lib/gcc/x86_64-linux-gnu/7 when linking -lgfortran.

If you plan to use this in production, be very careful. I don't know
about binary compatibility guarantees between g++-7 and clang++-10, so
you might have to recompile every C++-using R package from source with
clang++-10 in order to avoid hard-to-debug problems when using them
together. (It might also work fine. That's the worst thing about such
problems.)

-- 
Best regards,
Ivan

[1] https://en.cppreference.com/w/cpp/header/execution