What is the purpose of pthread_mutex in Linux?

In Linux, pthread_mutex (mutex) is used to achieve mutual exclusion between threads when accessing shared resources. It ensures that only one thread can access the resource at a time, preventing data races and unpredictable results that may occur when multiple threads access the resource simultaneously.

Specifically, the functions of pthread_mutex are as follows:

1. Exclusive access to shared resources: When a thread needs to access a shared resource, it can ensure that other threads cannot access the resource at the same time by acquiring a mutex lock. Once the thread finishes accessing, it releases the mutex lock so that other threads can continue accessing the shared resource.
2. To prevent race conditions: a race condition refers to a situation where multiple threads executing concurrently rely on the order of execution or timing for their results. By using mutex locks, race conditions can be prevented, ensuring that each thread accessing shared resources has exclusive access, thereby avoiding unpredictable outcomes.
3. Thread synchronization: Mutex lock can be used as a mechanism for coordinating the execution order of multiple threads. By locking and unlocking the mutex, it ensures that only one thread can enter the critical section of code, thus controlling the execution order of threads.

In summary, pthread_mutex plays a crucial role in Linux, used for achieving mutual exclusion and synchronization between threads, ensuring safe access to shared resources.