What is the purpose of async in C++?

In C++, async is a function template used to create asynchronous tasks. Its purpose is to create an asynchronous task and return a std::future object to retrieve the result of the asynchronous task.

Using async functions, you can run a block of code in a separate thread without blocking the current thread. This can improve the performance and response speed of a program, especially for tasks that require a long execution time, such as network requests and IO operations.

When using async functions, it is important to ensure that the execution of asynchronous tasks does not interfere with the main thread, and to properly handle the return values and exceptions of asynchronous tasks. Therefore, careful consideration of the program’s logic and thread management is necessary when using async functions.