CMake Cookbook

How to do it

Let us start with the same source code as for the previous recipe. We want to be able to toggle between two behaviors:

1. Build Message.hpp and Message.cpp into a library, static or shared, and then link the resulting library into the hello-world executable.
2. Build Message.hpp, Message.cpp, and hello-world.cpp into a single executable, without producing the library.

Let us construct CMakeLists.txt to achieve this:

1. We start out by defining the minimum CMake version, project name, and supported language:

cmake_minimum_required(VERSION 3.5 FATAL_ERROR)project(recipe-04 LANGUAGES CXX)

2. We introduce a new variable, USE_LIBRARY. This is a logical variable and its value will be set to OFF. We also print its value for the user:

set(USE_LIBRARY ...