Sysepollh

Sysepollh is a hypothetical software abstraction used in discussions of event-driven programming to unify the polling of system events across platforms. It provides a single interface to monitor input/output readiness, timers, and signals, enabling scalable, asynchronous software to respond to multiple event sources without blocking.

Usage and scope: The term is not an official standard but appears in academic and teaching contexts as a model for how an event loop might anonymize OS-specific polling mechanisms.

Architecture: A typical sysepollh design includes an event registry where sources such as sockets, files, timers, and internal signals are registered; a central poll loop that collects readiness notifications; and a dispatcher that invokes handlers or queues tasks. The API generally supports adding, modifying, and removing monitored sources and may provide both edge-triggered and level-triggered semantics.

Implementation notes: In practice, an implementation would map to OS-specific facilities such as epoll on Linux, kqueue on BSD/macOS, or IOCP on Windows, with fallbacks to select or poll where needed. Thread-safety, wakeup semantics, and fairness between sources are common considerations.

Applications and limitations: Sysepollh serves as a teaching model for building high-performance servers, GUI event loops, and real-time monitoring dashboards. As an abstraction, it introduces another layer that can incur overhead and may obscure platform-specific optimizations. Real-world libraries implement similar concepts under names like event loops or multiplexers.

See also: event loop, epoll, kqueue, IO multiplexing, non-blocking I/O.