What is thread safety in C++17's std::optional?

Can you explain what thread safety means in the context of C++17's std::optional?

Thread safety refers to the property of a data structure or function to operate safely in a multi-threaded environment. In C++17, std::optional is not inherently thread-safe, meaning that if multiple threads access the same std::optional instance simultaneously, it can lead to data races unless external synchronization is applied.

What are some common practices to ensure thread safety when using std::optional?

To ensure thread safety with std::optional, you can use mutexes to synchronize access, or you can use atomic operations if applicable. Another approach is to avoid sharing the same instance across threads.

Are there any specific scenarios where std::optional is particularly useful in a multi-threaded application?

Yes, std::optional is useful for representing optional values in multi-threaded applications, especially when combined with thread-safe data structures or when used in conjunction with synchronization mechanisms.

Can std::optional be used safely in a concurrent context without additional synchronization?

No, std::optional itself does not provide any built-in thread safety. You must implement your own synchronization if multiple threads will access the same instance.