One of the most important new features in the C++20 is coroutines. A coroutine is a function that has the ability to be suspended and resumed. A function becomes a coroutine if it uses any of the following:
- the co_await operator to suspend execution until resumed
- the co_return keyword to complete execution and optionally return a value
- the co_yield keyword to suspend execution and return a value
A coroutine must also have a return type that satisfies some requirements. However, the C++20 standard, only defines a framework for the execution of coroutines, but does not define any coroutine types satisfying such requirements. That means, we need to either write our own or rely on 3rd party libraries for this. In this post, I’ll show how to write some simple examples using the cppcoro library.