Semaphores
Semaphores are a synchronization primitive used in concurrent programming to control access to shared resources by multiple processes or threads. They are integer variables that support two atomic operations: wait (or P) to decrement the value and signal (or V) to increment it, often used to manage critical sections and prevent race conditions. Semaphores can be binary (with values 0 or 1) for mutual exclusion or counting (with non-negative integer values) for resource allocation.
Developers should learn semaphores when building multi-threaded or multi-process applications where shared resources like memory, files, or hardware need coordinated access to avoid conflicts and ensure data consistency. They are essential in operating systems, embedded systems, and distributed computing for implementing synchronization mechanisms such as producer-consumer problems, reader-writer locks, and bounded buffer management.