POSIX real-time extensions (based on POSIX 1003.1b) define extensions such as timers, priority scheduling, real-time signals, semaphores, memory queues, shared memory and memory locking that are useful for development of real-time systems. Extensions such as, timers and shared memory are supported by the Librt library, which conforms to the Linux Standard Base (LSB) 3.1 Specification. The Symbian platform supports the Librt library, which enables Symbian Developers to port Librt-based applications onto the Symbian platform quickly and easily.