CMake Cookbook

How to do it

Now let us turn to the CMake side. In the CMakeLists.txt file, we need to apply the following:

1. We first define the executable and its source file dependency:

cmake_minimum_required(VERSION 3.5 FATAL_ERROR)project(recipe-04 LANGUAGES CXX)add_executable(arch-dependent arch-dependent.cpp)

2. We check for the size of the void pointer type. This is defined in the CMAKE_SIZEOF_VOID_P CMake variable and will tell us whether the CPU is 32 or 64 bits. We let the user know about the detected size with a status message and set a preprocessor definition:

if(CMAKE_SIZEOF_VOID_P EQUAL 8)  target_compile_definitions(arch-dependent PUBLIC "IS_64_BIT_ARCH")  message(STATUS "Target is 64 bits")else() target_compile_definitions(arch-dependent PUBLIC ...