YouCompleteMe won't compile on Slackware14.2

I am trying to compile YouCompleteMe for vim. When I ran install.py, I got this error

Searching Python 3.7 libraries...
Found Python library: /usr/lib64/libpython3.7m.so
Found Python headers folder: /usr/include/python3.7m
-- The C compiler identification is GNU 5.5.0
-- The CXX compiler identification is GNU 5.5.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:232 (message):
  Your C++ compiler does NOT fully support C++17.


-- Configuring incomplete, errors occurred!
See also "/tmp/ycm_build_s90xbc7b/CMakeFiles/CMakeOutput.log".
ERROR: the build failed.

NOTE: it is *highly* unlikely that this is a bug but rather
that this is a problem with the configuration of your system
or a missing dependency. Please carefully read CONTRIBUTING.md
and if you're sure that it is a bug, please raise an issue on the
issue tracker, including the entire output of this script
and the invocation line used to run it.

The log file above doesn't exist

Originally Posted by Mackyboy123 -- The CXX compiler identification is GNU 5.5.0 ... Your C++ compiler does NOT fully support C++17.

The error message is pretty much saying it all.

Originally Posted by shruggy The error message is pretty much saying it all.

How do I get a c++ compiler that suipports c++17

Originally Posted by Mackyboy123 How do I get a c++ compiler that suipports c++17

That might be a bit complicated. From Wikipedia :

• GCC has had complete support for C++17 language features since version 8.
• Clang 5 and later implement all the features of C++17.
• Visual Studio 2017 15.8 (MSVC 19.15) supports all of C++17.

Upgrading compiler alone is hard job. You may want to target an older version of your software or consider upgrading to current.

pkgs.org says Slackware Extra for 14.2 includes llvm 8.0.1.

Originally Posted by shruggy pkgs.org

Slackware Extra

You'll have to trust those. I do not (know them).

You don't need to trust them, just trust any Slackware mirror:
https://mirror.bytemark.co.uk/slackw....2/extra/llvm/

Extra is an official Slackware repo. Have you noticed the green label Official on the pkgs.org page? They mark unofficial repos with the red label Third-Party.

Stand corrected, thanks ! I didn't realise it was the extra in official Slackware repo. I guess it might be because I haven't had a look tova 14.2 repo for a long time...

Originally Posted by shruggy Extra is an official Slackware repo. Have you noticed the green label Official on the pkgs.org page? They mark unofficial repos with the red label Third-Party.

Most don't recommend using pkgs.net for Slackware since the site doesn't document any dependencies, in addition to potential problems when mixing packages from two different repos.

That being said, official repos should be good.

There's a newer cmake on SBo which claims to install to /opt and not interfere with system cmake. README.Slackware contains instructions about how to use it (editing the SlackBuilds is required). I've never tried it yet though. But it's in my TODO, because I'm affected by this too. To make YCM compile, you might try aliasing the new cmake as cmake, so YCM transparently uses the new one. If you try this first (before me), please let us know here if it worked.

Edit: this post is misleading. Trying to compile YCM with the newer cmake produces the same error, since the problem is the C++ compiler, not cmake itself. So the options are either to try -current or use an older YCM version. I think 2-3 months ago it compiled fine with the C++ compiler that Slackware 14.2 provides. My file dates show it compiled fine at the beginning of November last year.