What is the function of a mutex in C++?

A mutex in C++ is a synchronization primitive used to achieve mutually exclusive access to shared resources between multiple threads.

The purpose of a mutex is to protect shared resources, ensuring that only one thread can access the shared resource at any given time. When a thread acquires the lock of a mutex, other threads will be blocked until the lock is released. This helps prevent data races and undefined behavior caused by multiple threads accessing the shared resource simultaneously.

A mutex provides two main operations: lock and unlock. When a thread wants to access a shared resource, it first tries to acquire the mutex lock (using the lock operation). If the lock is already held by another thread, the thread will be blocked until the lock is released. Once the thread completes its access to the shared resource, it releases the mutex lock (using the unlock operation), allowing other threads to acquire the lock and continue accessing the shared resource.

Using mutex can effectively synchronize operations between multiple threads, ensuring thread safety and avoiding data races. However, caution must be taken when using mutex to prevent issues like deadlocks and starvation.