Multi-threading

Having blocking functions in your code can be a real nuisance. Listening for incoming network connections or data, asking users to input something into the console, or even loading game data, like textures, maps, or sounds, can block a program from executing until it's done. Have you ever wondered how certain games have a loading bar that actually moves while the data is being loaded? How can that be done with code that is executed sequentially? The answer to that is multi-threading. Your application runs all its code sequentially from top to bottom in something referred to as the main thread. It is not a program, as it can't exist by itself. Instead, a thread only runs within your application. The beauty of this is that multiple threads can exist and run all at once, which enables parallel code execution. Consider the following diagram:

Let's say that the entire application space is the main thread, and all we do here is update and render the game. The example...