Error unsolved after troubleshooting: concept does not name a type

[FDemelas]

Hello, I installed Jluna on my Ubuntu 20.04, and the tests were successfully passed.

Anyway, now I'm trying to construct a simple "hello world" test, but I'm finding an error error: unknown type name 'concept' concept to_julia_type_convertable = requires(T) [and others...] similar to the one that you already consider in the troubleshooting: error: concept does not name a type.

I tried all the solutions that you proposed in the troubleshooting: updated my compilers (I tried clang++-12 and g++-10) and
_add target_compile_features(<your target> PRIVATE cxx_std_20)_ after the target creation.

Do you have any suggestions to solve the problem? Thank you in advance.

P.S.: I'm calling cmake with:

_cmake .. -DCMAKE_C_COMPILER=clang-12 -DCMAKE_CXX_COMPILER=clang++-12_

My CmakeList file is:

cmake_minimum_required(VERSION 3.12)

project(TestLib)

set(CMAKE_C_COMPILER "clang-12")
set(CMAKE_CXX_COMPILER "/usr/bin/clang++-12")
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -v  -rpath" )#-lpthread")

set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}")

find_library(jluna REQUIRED 
    NAMES jluna
    PATHS /home/user/jluna/
)

find_package(jluna REQUIRED)

add_executable(test test.cpp)

target_compile_features(test PRIVATE cxx_std_20)

target_link_libraries(test PRIVATE
    "${jluna}" 
    "${/home/user/julia-1.9.2/lib/}"
)

target_include_directories(test PRIVATE
    "/home/user/jluna"
    "/home/user/julia-1.9.2/include/julia"
)

[FDemelas]

Just a little update. I was able to compile the program 'at hand' using:

g++-10 -c ./test.cpp -o test.o -I "/home/user/julia-1.9.2/include/julia/" -I "/home/user/jluna/" -O3 -std=c++20 -DNDEBUG -DCLANG_1200_0_32_27_PATCH -fpic g++-10 -o ./JLUNA_test test.o -L "/home/user/julia-1.9.2/lib/" -ljulia -L "/home/user/jluna/jluna/lib/" -ljluna -O3 -std=c++20 -DNDEBUG -DCLANG_1200_0_32_27_PATCH -fpic

anyway, at execution time I found another error:

./JLUNA_test: error while loading shared libraries: /home/user/julia-1.9.2/lib/libjulia.so.1: only ET_DYN and ET_EXEC can be loaded

[Clemapfel]

Sorry for the late reply, could you try a newer clang, such as 14 or 16? I don't see anything wrong with your cmake and the concept error is a typical parsing error that signals that the compiler used has not yet implemented C++20 concepts

I will try to reproduce this using clang 12 on my ubuntu machine

[Clemapfel]

clem@ubuntu:~/Workspace/jluna/build$ cmake .. -DCMAKE_CXX_COMPILER=/usr/bin/clang++-12
-- Configuring done
-- Generating done
-- Build files have been written to: /home/clem/Workspace/jluna/build

clem@ubuntu:~/Workspace/jluna/build$ make
Consolidate compiler generated dependencies of target jluna
[  7%] Building CXX object CMakeFiles/jluna.dir
(...)
[100%] Linking CXX executable jluna_test
[100%] Built target jluna_test

clem@ubuntu:~/Workspace/jluna/build$ /usr/bin/clang++-12 -v 
Ubuntu clang version 12.0.1-19ubuntu3
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/11
Candidate multilib: .;@m64
Selected multilib: .;@m64

I tried to reproduce this and clang12 is definitely new enough, my best guess is that you are accidentally using an older clang version, for example your /usr/bin/clang could actually be a symbolic link to an older version

[francescoDemelas]

Hello, thank you for your help. Sadly I still find the same error. I tried also with clang16, but nothing changed:

cmake .. -DCMAKE_C_COMPILER=/usr/bin/clang-16 -DCMAKE_CXX_COMPILER=/usr/bin/clang++-16 -- The C compiler identification is Clang 16.0.6 -- The CXX compiler identification is Clang 16.0.6 -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working C compiler: /usr/bin/clang-16 - skipped -- Detecting C compile features -- Detecting C compile features - done -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Check for working CXX compiler: /usr/bin/clang++-16 - skipped -- Detecting CXX compile features -- Detecting CXX compile features - done -- Configuring done (0.4s) -- Generating done (0.0s) -- Build files have been written to: /home/user/provaJluna/build

but then the make command fails with the same error:

In file included from /home/user/provaJluna/test.cpp:1: In file included from /home/user/jluna/jluna.hpp:11: In file included from /home/user/jluna/include/exceptions.hpp:9: /home/user/jluna/include/typedefs.hpp:91:5: error: unknown type name 'concept' concept to_julia_type_convertable = requires(T) ^ [....]

I tried to reinstall both Jluna and Julia (to a newer version), but this did not solve the problem.

[Clemapfel]

I'm still actively investigating this issue, I'll try to write you up an example project you can just clone to eliminate any possible errors, the docs should have one anyway

[Clemapfel]

I created an example project for you.

Please run, in any public directory:

# in <path>
git clone https://github.com/clemapfel/jluna
cd jluna
git fetch
git checkout example
mv example ../jluna_example
cd ../jluna_example

The folder jluna_example in the directory you ran the above in contains a full cmake project that should hopefully just work. To compile it, run:

# in <path>/jluna_example
mkdir build
cd build
cmake ..
make
./jluna_example

If an error saying it can't find the jluna headers occurs, edit line 10 in jluna_example/CMakeLists.txt to the folder of the jluna includes, "/home/user/jluna" in your original cmake.

If this works, simply base your project off jluna_example, I formatted in a way so it's easy to edit.

[Clemapfel]

If this still gives the same error, please add the following lines to your (or jluna_examples) CMakeLists.txt

get_cmake_property(_variableNames VARIABLES)
list (SORT _variableNames)
foreach (_variableName ${_variableNames})
    message(STATUS "${_variableName}=${${_variableName}}")
endforeach()

then run cmake .. again. It should print a long list of names, please post that list.

[francescoDemelas]

Thank you very much, with your example everything works fine. Finally, there was some problem in my file CMake. I tried to better understand where was the problem and it seems that it was not able to correctly find my installation of Jluna in my home, but I have no problems with the one in /usr/local/... You can close the issue, thank you again!