Signal programming is often used in the same sense as Event-driven programming. The word signal is used instead of the word event in documentation of such libraries as Qt, GTK+ and libsigc++. In the wider SW community the word signal is sometimes used especially to denote synchronous rather than asynchronous events, while the word event is often used for asynchronous event queues, but this is by no means universal. Especially in the Telecomms industry, "signal" is used to mean any event, notably (in the SW context) messages within a message passing architecture. One application of synchronous signal programming is observer pattern. Also signal programming is used in a narrow sense of programming with Unix signals such as SIGTERM, SIGSEGV etc. Note that Unix signals are asynchronous.
