C++ High Performance

Synchronous and asynchronous tasks

We will refer to synchronous and asynchronous tasks or function calls in this chapter. Synchronous tasks are like the ordinary functions that we are used to in a C++ program. When a synchronous task is finished doing whatever it is supposed to do, it will return the control to the caller of the task. The caller of the task is waiting or blocked until the synchronous task has finished.

An asynchronous task, on the other hand, will return the control back to the caller immediately and instead perform its work concurrently. The sequence in the following diagram shows the difference between calling a synchronous and asynchronous task, respectively:

Synchronous versus asynchronous calls. The asynchronous task ...