A coroutine is a programming construct that represents a block of code that can be stopped and restarted, maintaining its execution state between suspensions.
In Ruby Concurrency Mechanisms, Fibers are Ruby’s implementation of coroutines. They provide the underlying mechanism for Cooperative Multitasking, where control flow can be explicitly managed by the developer.
Implementation
Coroutines differ from regular functions in that they:
- Can pause execution mid-way through their logic
- Preserve their local state (variables, execution position) across suspensions
- Resume execution from where they left off when reactivated
This makes them ideal for implementing asynchronous patterns, as seen in Async Ruby frameworks that leverage fibers for high-Concurrency O workloads.
Ruby’s coroutine implementation includes multiple platform-specific versions (arm64, x86, pthread, etc.) to optimize performance across different architectures.