P21575R15

P21575R15 is a working draft paper in the C++ Standards Committee’s repository, part of the broader effort to evolve the C++ programming language. The document was introduced as a response to the growing demand for modern, expressive, and efficient ways to handle asynchronous programming in C++. It builds upon earlier proposals and aims to refine and standardize the design of coroutines, a key feature for writing asynchronous and concurrent code.

The primary focus of P21575R15 is the formalization of the coroutine infrastructure, which includes mechanisms for suspending and resuming execution, managing coroutine state, and enabling cooperative multitasking. Coroutines allow developers to write non-blocking code that can pause and resume execution without yielding control to the operating system, making them particularly useful for I/O-bound and event-driven applications. The proposal introduces syntax and semantics for defining coroutines, including the use of `co_await`, `co_yield`, and `co_return` keywords, which streamline asynchronous workflows.

The document also addresses concerns related to performance, memory management, and interoperability with existing C++ code. It proposes a design that minimizes runtime overhead while maintaining compatibility with the language’s existing features. The coroutine model outlined in P21575R15 is intended to be a foundational component of C++23, though its final form may evolve based on feedback from the standards committee and the broader developer community.

As with all working drafts, P21575R15 is subject to revision and discussion. The paper is available for review on the C++ Standards Committee’s public repository, where stakeholders can provide input, suggest improvements, or raise concerns before the feature is formally adopted into the C++ standard. The goal is to ensure that the final implementation is robust, widely applicable, and aligned with the needs of modern C++ development.