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race condition

A bug where the result depends on which thread happens to get there first.

A race condition occurs when correctness depends on the timing of unsynchronized accesses to shared state, at least one of them a write.

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Examples

  • Two threads each running count++ 1,000 times can finish below 2,000, because each ++ is a read, an add and a write.

See also

lock atomic operation concurrency
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