Chapter 7. Thread Synchronization

The word mutex is derived from the term mutual exclusion. A mutex is a POSIX threads construct, and is created using the pthread_create_mutex library call. A mutex serializes access to each section of code, so that only one thread of an application is running the code at any one time.

Similar to a mutex is a futex, or Fast User muTEX, which is an internal mechanism used to implement mutexes. Futexes use shared conventions between the kernel and the C library. This allows an uncontended mutex to be locked or freed without a context switch to kernel space.