CMake Cookbook

Getting ready

For this example, we will modify the hello-world.cpp example code from Chapter 1, From a Simple Executable to Libraries, Recipe 1, Compiling a single source file into an executable:

#include <cstdlib>#include <iostream>#include <string>std::string say_hello() {#ifdef IS_WINDOWS  return std::string("Hello from Windows!");#elif IS_LINUX  return std::string("Hello from Linux!");#elif IS_MACOS  return std::string("Hello from macOS!");#else  return std::string("Hello from an unknown system!");#endif}int main() {  std::cout << say_hello() << std::endl;  return EXIT_SUCCESS;}