timerid

Timerid (also written timerId, timer_id or TimerID) refers to the identifier returned by an operating system or programming runtime when a timer or timeout source is created. It is used to reference, manage or cancel that specific timer later. The exact form and semantics of a timerid depend on the environment: it may be an integer index, an opaque handle, or a pointer-like value, and it is typically valid only within the context that created it (process, thread, or event loop).

Common examples include the numeric handles returned by JavaScript's setTimeout and setInterval, the integerreturned by Qt's startTimer, GLib’s g_timeout_add identifier, the Win32 timer identifier used with SetTimer and KillTimer, and POSIX timers created by timer_create. When a timer event fires the system delivers an associated callback, message or signal; the timerid allows that delivery to be correlated with the originating timer.

Characteristics of timerids include limited lifetime (they may be invalid after cancellation or program termination), possible reuse by the system, and differing thread-safety guarantees. Best practices are to store the identifier if cancellation is needed, avoid assuming numeric properties of the value, cancel timers when no longer required to prevent resource leaks, and consider race conditions when cancelling timers concurrently. Timerids are implementation-specific and should not be treated as secure tokens or used for broader identification beyond timer management.