Thursday, April 14, 2022

[SOLVED] How do I activate C++ 11 in CMake?

Issue

When I try to run a CMake generated makefile to compile my program, I get the error that

range based for loops are not supported in C++ 98 mode.

I tried adding add_definitions(-std=c++0x) to my CMakeLists.txt, but it did not help.

I tried this too:

if(CMAKE_COMPILER_IS_GNUCXX)
    add_definitions(-std=gnu++0x)
endif()

When I do g++ --version, I get:

g++ (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1

I have also tried SET(CMAKE_CXX_FLAGS "-std=c++0x"), which also does not work.

I do not understand how I can activate C++ 11 features using CMake.


Solution

As it turns out, SET(CMAKE_CXX_FLAGS "-std=c++0x") does activate many C++11 features. The reason it did not work was that the statement looked like this:

set(CMAKE_CXX_FLAGS "-std=c++0x ${CMAKE_CXX_FLAGS} -g -ftest-coverage -fprofile-arcs")

Following this approach, somehow the -std=c++0x flag was overwritten and it did not work. Setting the flags one by one or using a list method is working.

list( APPEND CMAKE_CXX_FLAGS "-std=c++0x ${CMAKE_CXX_FLAGS} -g -ftest-coverage -fprofile-arcs")


Answered By - Subhamoy S.
Answer Checked By - Gilberto Lyons (WPSolving Admin)
at