Mutexes

A mutex, short for mutual exclusion, is a synchronization primitive used to prevent concurrent access to a shared resource by multiple threads or processes. It is a locking mechanism that ensures that only one thread can access the critical section of code at a time, thereby preventing race conditions and ensuring data consistency.

1. Mutual Exclusion: Only one thread can hold the mutex at any given time. If a thread tries to acquire a mutex that is already held by another thread, it will be blocked until the mutex is released.
2. Ownership: The thread that acquires the mutex is the owner of the mutex and is responsible for releasing it. Other threads cannot release a mutex they do not own.
3. Blocking: If a thread tries to acquire a mutex that is already held by another thread, it will be blocked until the mutex becomes available.
4. Non-reentrant: A thread that already owns a mutex cannot acquire it again without first releasing it. This is to prevent deadlocks and ensure proper synchronization.

Mutexes are commonly used in multithreaded programming to protect shared data structures and ensure that only one thread can modify the data at a time. They are implemented in various programming languages and operating systems, with different names and semantics, such as std::mutex in C++, Mutex in Java, and threading.Lock in Python.