Dealing with platform-dependent source code

The code for this recipe is available at https://github.com/dev-cafe/cmake-cookbook/tree/v1.0/chapter-02/recipe-02 and has a C++ example. The recipe is valid with CMake version 3.5 (and higher) and has been tested on GNU/Linux, macOS, and Windows.

Ideally, we should avoid platform-dependent source code, but sometimes we have no choice – particularly when we are given code to configure and compile that we have not written ourselves. In this recipe, we will demonstrate how to use CMake to conditionally compile source code depending on the OS.

Getting ready

For this example, we will modify the hello-world.cpp example code from Chapter 1, From a Simple Executable to Libraries...