Glossary

Coroutines

TL;DR

Coroutines are lightweight threads or cooperative multitasking constructs that allow functions to pause and resume execution at specific points, enabling efficient asynchronous programming and concurrent execution without the overhead of traditional threads.

Concept

Coroutines are a programming construct that enables functions to pause their execution at certain points and later resume from where they left off. Unlike traditional threads that are managed by the operating system, coroutines are managed by the application or runtime environment, making them more lightweight and efficient.

Key characteristics of coroutines include:

  1. Cooperative Multitasking: Coroutines voluntarily yield control to other coroutines rather than being preemptively switched by the OS scheduler.

  2. State Preservation: When a coroutine pauses, its local state (variables, execution context) is preserved, allowing it to resume exactly where it left off.

  3. Lightweight: Coroutines have minimal overhead compared to OS threads, allowing thousands to run concurrently without significant performance impact.

  4. Asynchronous Programming: Coroutines are commonly used in asynchronous programming to write non-blocking code that appears synchronous, improving code readability and maintainability.

Coroutines are widely used in modern programming languages and frameworks such as Python (async/await), Kotlin (suspend functions), JavaScript (async/await), and Go (goroutines). They enable developers to write efficient concurrent applications for handling I/O operations, web requests, and other tasks that would otherwise block the execution thread.

By using coroutines, developers can achieve better performance and resource utilization while maintaining clean, readable code that’s easier to reason about than traditional callback-based asynchronous programming approaches.

Related words: Modifiers Backwards Compatible Breaking Change