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Condition Variables - Senior

Correct coordination must handle startup, shutdown, cancellation, multiple predicates, and object destruction.

stateDiagram-v2 Running --> Draining: shutdown requested Draining --> Stopped: queue empty Running --> Stopped: abort

Include shutdown in every wait predicate, set it under the mutex, then broadcast. Ensure no waiter can access a destroyed condition variable. Prefer a queue, latch, barrier, or future when it directly expresses the protocol; raw condition variables expose too much lifecycle state.

Track waiting threads, wakeups per useful transition, wait duration, and herd size. Stress missed timing windows with randomized scheduling.

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Test yourself

  1. How does shutdown release every waiter?
  2. What makes condition-variable destruction safe?
  3. When is a latch clearer than a condition variable?