CMakeLists.txt

# set minimum cmake version
cmake_minimum_required(VERSION 3.5 FATAL_ERROR)

# project name and language
project(recipe-04 LANGUAGES CXX)

# define executable and its source file
add_executable(arch-dependent arch-dependent.cpp)

# let the preprocessor know about the size of void *
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 "IS_32_BIT_ARCH")
  message(STATUS "Target is 32 bits")
endif()

# let the preprocessor know about the host processor architecture
if(CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "i386")
  message(STATUS "i386 architecture detected")
elseif(CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "i686")
  message(STATUS "i686 architecture detected")
elseif(CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "x86_64")
  message(STATUS "x86_64 architecture detected")
else()
  message(STATUS "host processor architecture is unknown")
endif()

target_compile_definitions(arch-dependent
  PUBLIC "ARCHITECTURE=${CMAKE_HOST_SYSTEM_PROCESSOR}"
  )