Levels of Thread Safety
Software libraries can provide certain thread-safety guarantees. For example, concurrent reads might be guaranteed to be thread-safe, but concurrent writes might not be. Whether or not a program using such a library is thread-safe depends on whether it uses the library in a manner consistent with those guarantees.
Different vendors use slightly different terminology for thread-safety:
- Thread safe: Implementation is guaranteed to be free of race conditions when accessed by multiple threads simultaneously.
- Conditionally safe: Different threads can access different objects simultaneously, and access to shared data is protected from race conditions.
- Not thread safe: Code should not be accessed simultaneously by different threads.
Thread safety guarantees usually also include design steps to prevent or limit the risk of different forms of deadlocks, as well as optimizations to maximize concurrent performance. However, deadlock-free guarantees can not always be given, since deadlocks can be caused by callbacks and violation of architectural layering independent of the library itself.
Read more about this topic: Thread Safety
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