Mastering Linux Kernel Development

POSIX semaphores

POSIX semaphore semantics are rather simple when compared to System V. Each semaphore is a simple counter that can never be less than zero. The implementation provides function interfaces for initialization, increment, and decrement operations. They can be used for synchronizing threads by allocating the semaphore instance in memory accessible to all the threads. They can also be used for synchronizing processes by placing the semaphore in shared memory. Linux implementation of POSIX semaphores is optimized to deliver better performance for non-contending synchronization scenarios.

POSIX semaphores are available in two variants: named semaphores and unnamed semaphores. A named semaphore is identified by a filename and is ...