Are std::vector and boost::vector Truly Thread-Safe?

Thread Safety of Standard and Boost Vectors

Concurrent access to shared data structures, such as vectors, can introduce potential thread safety issues. Let's examine the thread safety implications of using std::vector and boost::vector.

Thread Safety of std::vector

The C standard provides certain threading guarantees for standard library classes, including std::vector. These guarantees state that:

• Multiple threads can concurrently read from the same container (std::vector).
• If one thread is writing to the container, no other threads can read or write to it simultaneously.

These guarantees may differ from expectations, as they do not provide complete thread safety for concurrent write access to containers.

Thread Safety of boost::vector

To cater to scenarios requiring thread-safe containers, the boost library introduced boost::vector from version 1.48.0 onwards. However, the thread safety properties of boost::vector are very similar to those of std::vector. They also adhere to the same threading guarantees, as specified in the C standard:

• Multiple concurrent readers can access the container.
• Only a single thread can write to the container at a time, and there can be no concurrent readers while a write operation is in progress.

Conclusion

Both std::vector and boost::vector provide limited thread safety for concurrent read operations. However, for concurrent write access, users must implement their own synchronization mechanisms to ensure data integrity. Therefore, the decision between using std::vector and boost::vector hinges on additional factors and specific application requirements, rather than contrasting their thread safety characteristics.

The above is the detailed content of Are std::vector and boost::vector Truly Thread-Safe?. For more information, please follow other related articles on the PHP Chinese website!