Understanding std::shared_mutex from C++17
https://www.cppstories.com/2026/shared_mutex/
A basic example using std::mutex is presented to illustrate a thread‑safe counter, followed by an explanation of its limitation: all accesses, including reads, are serialized. The impact of this bottleneck is demonstrated with a workload that performs many reads and few writes, showing that exclusive locking reduces scalability. std::shared_mutex is then introduced as a reader‑writer mutex that supports shared ownership for concurrent reads and exclusive ownership for writes. The counter code is refactored to use std::shared_lock for reads and std::unique_lock for writes, enabling multiple readers to hold the lock simultaneously. A benchmark comparing the two implementations under a read‑heavy scenario reports a substantial reduction in total execution time when std::shared_mutex is used.