What are the limitations of thread-local storage in C++11?

What are the limitations of thread-local storage in C++11?

Thread-local storage in C++11 allows variables to be unique to each thread, but it has some limitations. For instance, it can increase memory usage since each thread has its own copy of the variable. Additionally, thread-local storage is not suitable for all types of data, especially if you need to share data between threads.

Can you explain how it affects performance?

Using thread-local storage can lead to performance overhead due to the management of separate instances for each thread. If many threads are created, the memory allocation and deallocation can become costly. However, it can improve performance in scenarios where thread contention is high, as it reduces the need for locks.

Are there any alternatives to thread-local storage?

Yes, alternatives include using mutexes for shared data access, or employing thread pools where shared resources are managed more efficiently. You can also consider using atomic variables for simple data types that require minimal synchronization.

What are some common use cases for thread-local storage?

Common use cases include storing user session data in web servers, managing database connections per thread, and maintaining state information in multi-threaded applications.