Expert · Module 10 · Lesson 5 of 12
Coroutine Lifecycles, Trampolines, and State Machines
Engineer a complete cooperative coroutine lifecycle engine in C, manage state transitions, handle clean termination via entry trampolines, and prevent self-referential use-after-free bugs.
By the end you can
- Model explicit coroutine lifecycle states across CREATED, READY, RUNNING, SUSPENDED, and DEAD
- Implement the trampoline pattern to intercept normal function returns and route back to the scheduler
- Pass arbitrary user arguments and capture return codes safely across stack boundaries
- Prevent self-referential use-after-free bugs by delegating stack reclamation to the scheduler
Builds on Manual Assembly Context Switching: Callee-Saved Registers and Stack Pivots.
01 · A question first
What happens when a coroutine hits the closing brace of its entry function? If an execution context returns normally without yielding, where does the CPU jump? Without a trampoline, it pops an invalid address and crashes the process.
Make a guess before you read on.
02 · The idea
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What's inside
- Start with the problem
- How the idea works
- Complete Working Implementation: The Cooperative Fiber Engine
- Why it is correct
- What it costs
- Pitfalls and variations
- Where it is used
03 · Practice
Asked in interviews
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