Understanding std::counting_semaphore and std::binary_semaphore from C++20

This article explains the two semaphore types introduced in C++20: std::counting_semaphore and std::binary_semaphore. We’ll first use a counting semaphore to limit how many threads can operate at the same time. Then we’ll use a binary semaphore to send a signal between threads. We’ll also look at timed waiting, a small RAII helper, and a few more details.