尽管我将 target_compile_features 设置为 cxx_std_17

Question

I updated the versions of GCC and CMake. After the update CMake no longer sets the right command line option for the c++ standard.

Here is how I set it:

add_library(project_options INTERFACE)
target_compile_features(project_options INTERFACE cxx_std_17)

and then I link to the project_options

target_link_libraries(app PRIVATE project_options)

With GCC 8.3 (on rhel) this sets the std compile flag to -std=gnu17

Now it is set to -std=c++11

If I set the compiler globally it works as expected:

set(CMAKE_CXX_STANDARD 17)

What am I missing? Or is this a bug in the new Tools?

My System:

• GCC: 11.1.0
• CMake: 3.20.2

Answer 1

You need to set the target property CXX_STANDARD to an appropriate value.

set_target_properties(project_options PROPERTIES CXX_STANDARD 17)

See documentation and here for further details.