Concurrency-related classes and functions in the C++ Standard Library

1. std::thread: You can create a new thread of execution by creating an instance of std::thread. For example, you could create a thread to perform a long-running computation in the background while the main thread of the program continues to run.

2. std::mutex: You can use a mutex to protect access to shared resources, such as a shared data structure. By locking the mutex before accessing the resource, you can ensure that only one thread can access the resource at a time. For example, you could use a mutex to protect access to a queue that is shared between multiple threads.

3. std::atomic: You can use an atomic variable to perform atomic operations on a shared variable, such as incrementing a counter. Atomic operations are guaranteed to be performed as a single, indivisible operation, so you can avoid race conditions and other concurrency issues. For example, you could use an atomic variable to keep track of the number of items that have been processed by multiple threads.

4. std::condition_variable: You can use a condition variable to synchronize the execution of multiple threads. A condition variable allows a thread to wait until a particular condition has been met before proceeding. For example, you could use a condition variable to allow a thread to wait until a shared data structure has been updated before accessing it.

5. std::future: You can use a future to represent a value that may not yet be available. For example, you could use a future to represent the result of a long-running computation that is being performed in another thread.

6. std::promise: You can use a promise to associate a value with a future. For example, you could use a promise to set the result of a long-running computation and then use the associated future to retrieve the result.

7. std::packaged_task: You can use a packaged task to package a function and its arguments into a single object that can be executed asynchronously. For example, you could use a packaged task to run a function in a background thread and then retrieve the result using the future.

8. std::async: You can use the std::async function to run a function asynchronously and return a future representing the result. For example, you could use std::async it to run a function in a background thread and then retrieve the result using a future.

9. std::chrono: You can use the std::chrono library to work with time durations and time points. For example, you could use std::chrono it to measure the execution time of a function or to implement timeouts for synchronization primitives like condition variables.