Cilk plus annotation using JetBrains Clion IDE (C++)

Question

I need to use the cilk plus annotations in my C++ program, something like:

#inlcude <cilk/cilk.h>

cilk_spawn myFunction();
cilk_sync;

I'm using JetBrains CLion IDE and I'm getting the error Error after macro substitution: can't resolve type '_Cilk_spawn'. I'm wondering whether there is any solution. Of course, using g++ straight from my terminal, i simply add the option -fcilkplus, but in this case I don't know how to solve this problem. Here is the content of my CMakeLists.txt file (updated):

cmake_minimum_required(VERSION 3.8)
project(C__Threads)

set(CMAKE_CXX_STANDARD 11)
set(SOURCE_FILES main.cpp)
set(CMAKE_CXX_FLAGS "-fcilkplus") // I've also put this one because otherwise the building process fails.

add_executable(C__Threads ${SOURCE_FILES})
target_compile_options(C__Threads PUBLIC -fcilkplus)
set(CMAKE_VERBOSE_MAKEFILE ON)

And this is the build output (updated):

/home/leo/clion-2017.2.3/bin/cmake/bin/cmake --build /home/leo/CLionProjects/C++Threads/cmake-build-debug --target C__Threads -- -j 4
/home/leo/clion-2017.2.3/bin/cmake/bin/cmake -H/home/leo/CLionProjects/C++Threads -B/home/leo/CLionProjects/C++Threads/cmake-build-debug --check-build-system CMakeFiles/Makefile.cmake 0
/usr/bin/make -f CMakeFiles/Makefile2 C__Threads
make[1]: Entering directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
/home/leo/clion-2017.2.3/bin/cmake/bin/cmake -H/home/leo/CLionProjects/C++Threads -B/home/leo/CLionProjects/C++Threads/cmake-build-debug --check-build-system CMakeFiles/Makefile.cmake 0
/home/leo/clion-2017.2.3/bin/cmake/bin/cmake -E cmake_progress_start /home/leo/CLionProjects/C++Threads/cmake-build-debug/CMakeFiles 2
/usr/bin/make -f CMakeFiles/Makefile2 CMakeFiles/C__Threads.dir/all
make[2]: Entering directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
/usr/bin/make -f CMakeFiles/C__Threads.dir/build.make CMakeFiles/C__Threads.dir/depend
make[3]: Entering directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
cd /home/leo/CLionProjects/C++Threads/cmake-build-debug && /home/leo/clion-2017.2.3/bin/cmake/bin/cmake -E cmake_depends "Unix Makefiles" /home/leo/CLionProjects/C++Threads /home/leo/CLionProjects/C++Threads /home/leo/CLionProjects/C++Threads/cmake-build-debug /home/leo/CLionProjects/C++Threads/cmake-build-debug /home/leo/CLionProjects/C++Threads/cmake-build-debug/CMakeFiles/C__Threads.dir/DependInfo.cmake --color=
make[3]: Leaving directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
/usr/bin/make -f CMakeFiles/C__Threads.dir/build.make CMakeFiles/C__Threads.dir/build
make[3]: Entering directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
[ 50%] Building CXX object CMakeFiles/C__Threads.dir/main.cpp.o
/usr/bin/c++    -fcilkplus -g   -fcilkplus -std=gnu++11 -o CMakeFiles/C__Threads.dir/main.cpp.o -c /home/leo/CLionProjects/C++Threads/main.cpp
[100%] Linking CXX executable C__Threads
/home/leo/clion-2017.2.3/bin/cmake/bin/cmake -E cmake_link_script CMakeFiles/C__Threads.dir/link.txt --verbose=1
/usr/bin/c++  -fcilkplus -g   CMakeFiles/C__Threads.dir/main.cpp.o  -o C__Threads 
make[3]: Leaving directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
[100%] Built target C__Threads
make[2]: Leaving directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'
/home/leo/clion-2017.2.3/bin/cmake/bin/cmake -E cmake_progress_start /home/leo/CLionProjects/C++Threads/cmake-build-debug/CMakeFiles 0
make[1]: Leaving directory '/home/leo/CLionProjects/C++Threads/cmake-build-debug'

Answer 1

You need to set CMAKE_CXX_FLAGS before you create the target with add_executable.

However, I suggest you use target_compile_option instead:

target_compile_options(C__Threads PUBLIC -fcilkplus)

Of course, this has to be done after the add_executable.