cmake keeps adding the std=gnu++11 option

Question

I'm trying to compile a project in C++ using cmake, and in the page of the project they tell me that it will crash if I don't add the standard 98. (I'm on a mac) I've tried all I found on the internet and I could manage to make the cmake use the option -std=c++98 but it also adds -DNDEBUG -std=gnu++11. (I saw it using the make VERBOSE=1 option)

I would like to get rid of that. Using the --trace option I could see that the option is set in a file which is in the cellar folder, that is, is something that has to do with cmake itself and not in the CMakeList.txt file im using.

How can I solve this problem?

If it can help the code I'm trying to compile is this: SAMoS

Thank you.

UPDATE:

with the --trace option I was able to see that the -std=gnu++11 option was selected in the file:

/usr/local/Cellar/cmake/3.9.4.1/share/cmake/Modules/Compiler/GNU-CXX.cmake which can be seen here GNU-CXX.cmake

If I eddit that file in a way that every if sets the option to -std=c++98 then, the cmake complains giving me the next error:

CMake Error in src/CMakeLists.txt:

The compiler feature "cxx_nullptr" is not known to CXX compiler

"GNU"

version 7.2.0.

I don't know what else can I try...

Answer 1

You need to set the language standard:

set(CMAKE_CXX_STANDARD 98)

Depending on the compiler, it may enable extensions as well. To disable the GNU extensions also add:

set(CMAKE_CXX_EXTENSIONS OFF)

Note that setting this options does so only for the specified target and dependent targets.

Have take a look at this section of the CMake manual for more information on compiler features. Do note however, using this