POSIXtimer

POSIXTimer is a standard timer API defined by the Portable Operating System Interface (POSIX) specifications, which provides a portable, consistent way for applications to create and manage timers. These timers are primarily used to invoke a specific action or callback after a designated period or at specified intervals, facilitating asynchronous event handling and time-dependent operations within software systems.

POSIXTimers can be of two types: one-shot timers, which trigger only once after a specified duration, and periodic timers, which trigger repeatedly at fixed intervals. They are typically implemented using system calls such as timer_create, timer_settime, and timer_delete. When a timer expires, it can notify the application through various mechanisms, including signals, or by invoking a specified callback function in real-time systems.

The API supports multiple clock sources, such as the real-time clock (CLOCK_REALTIME) and the monotonically increasing clock (CLOCK_MONOTONIC), allowing developers to select appropriate timing mechanisms based on application requirements. Timer resolution and notification methods can vary depending on the underlying system capabilities.

POSIXTimers are widely supported across Unix-like operating systems, including Linux, macOS, and other POSIX-compliant systems, providing a standardized approach to managing timers in portable software development. They are instrumental in applications requiring timed events, such as task scheduling, timeout handling, and periodic data sampling.

Overall, POSIXTimer offers a flexible and reliable interface for managing timers within POSIX-compliant environments, contributing to the portability and robustness of time-dependent applications.