/** @file * * InnoTek Portable Runtime - Timer. */ /* * Copyright (C) 2006 InnoTek Systemberatung GmbH * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License as published by the Free Software Foundation, * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE * distribution. VirtualBox OSE is distributed in the hope that it will * be useful, but WITHOUT ANY WARRANTY of any kind. * * If you received this file as part of a commercial VirtualBox * distribution, then only the terms of your commercial VirtualBox * license agreement apply instead of the previous paragraph. */ #ifndef __iprt_timer_h__ #define __iprt_timer_h__ #include #include __BEGIN_DECLS /** @defgroup grp_rt_timer RTTimer - Timer * * The IPRT timer API provides a simple abstraction of recurring and one-shot callback timers. * * Because of the great variation in the native APIs and the quality of * the service delivered by those native APIs, the timers are operated * on at best effort basis. * * All the ring-3 implementations are naturally at the mercy of the scheduler, * which means that the callback rate might vary quite a bit and we might skip * ticks. Many systems have a restriction that a process can only have one * timer. IPRT currently makes no efforts at multiplexing timers in those kind * of situations and will simply fail if you try to create more than one timer. * * Things are generally better in ring-0. The implementations will use interrupt * time callbacks wherever available, and if not, resort to a high priority * kernel thread. * * @ingroup grp_rt * @{ */ /** Timer handle. */ typedef struct RTTIMER *PRTTIMER; /** * Timer callback function. * * The context this call is made in varies with different platforms and * kernel / user mode IPRT. * * In kernel mode a timer callback should not waste time, it shouldn't * waste stack and it should be prepared that some APIs might not work * correctly because of weird OS restrictions in this context that we * haven't discovered and avoided yet. Please fix those APIs so they * at least avoid panics and weird behaviour. * * @param pTimer Timer handle. * @param pvUser User argument. */ typedef DECLCALLBACK(void) FNRTTIMER(PRTTIMER pTimer, void *pvUser); /** Pointer to FNRTTIMER() function. */ typedef FNRTTIMER *PFNRTTIMER; /** * Create a recurring timer. * * @returns iprt status code. * @param ppTimer Where to store the timer handle. * @param uMilliesInterval Milliseconds between the timer ticks. * This is rounded up to the system granularity. * @param pfnTimer Callback function which shall be scheduled for execution * on every timer tick. * @param pvUser User argument for the callback. * @see RTTimerDestroy, RTTimerStop */ RTDECL(int) RTTimerCreate(PRTTIMER *ppTimer, unsigned uMilliesInterval, PFNRTTIMER pfnTimer, void *pvUser); /** * Create a suspended timer. * * @returns iprt status code. * @param ppTimer Where to store the timer handle. * @param u64NanoInterval The interval between timer ticks specified in nanoseconds if it's * a recurring timer. This is rounded to the fit the system timer granularity. * For one shot timers, pass 0. * @param fFlags Timer flags. No flags has been defined yet, pass 0. * @param pfnTimer Callback function which shall be scheduled for execution * on every timer tick. * @param pvUser User argument for the callback. * @see RTTimerStart, RTTimerStop, RTTimerDestroy, RTTimerGetSystemGranularity */ RTDECL(int) RTTimerCreateEx(PRTTIMER *ppTimer, uint64_t u64NanoInterval, unsigned fFlags, PFNRTTIMER pfnTimer, void *pvUser); /** * Stops and destroys a running timer. * * @returns iprt status code. * @param pTimer Timer to stop and destroy. NULL is ok. */ RTDECL(int) RTTimerDestroy(PRTTIMER pTimer); /** * Stops an active timer. * * @returns IPRT status code. * @retval VERR_INVALID_HANDLE if pTimer isn't valid. * @retval VERR_TIMER_ACTIVE if the timer isn't suspended. * * @param pTimer The timer to activate. * @param u64First The RTTimeSystemNanoTS() for when the timer should start firing. * If 0 is specified, the timer will fire ASAP. * @see RTTimerStop */ RTDECL(int) RTTimerStart(PRTTIMER pTimer, uint64_t u64First); /** * Stops an active timer. * * @returns IPRT status code. * @retval VERR_INVALID_HANDLE if pTimer isn't valid. * @retval VERR_TIMER_SUSPENDED if the timer isn't active. * @retval VERR_NOT_SUPPORTED if the IPRT implementation doesn't support stopping a timer. * * @param pTimer The timer to suspend. * @see RTTimerStart */ RTDECL(int) RTTimerStop(PRTTIMER pTimer); /** * Gets the (current) timer granularity of the system. * * @returns The timer granularity of the system in nanoseconds. * @see RTTimerRequestSystemGranularity */ RTDECL(uint32_t) RTTimerGetSystemGranularity(void); /** * Requests a specific system timer granularity. * * Successfull calls to this API must be coupled with the exact same number of * calls to RTTimerReleaseSystemGranularity() in order to undo any changes made. * * * @returns IPRT status code. * @retval VERR_NOT_SUPPORTED if the requested value isn't supported by the host platform * or if the host platform doesn't support modifying the system timer granularity. * @retval VERR_PERMISSION_DENIED if the caller doesn't have the necessary privilege to * modify the system timer granularity. * * @param u32Request The requested system timer granularity in nanoseconds. * @param pu32Granted Where to store the granted system granularity. This is the value * that should be passed to RTTimerReleaseSystemGranularity(). It * is what RTTimerGetSystemGranularity() would return immediately * after the change was made. * * The value differ from the request in two ways; rounding and * scale. Meaning if your request is for 10.000.000 you might * be granted 10.000.055 or 1.000.000. * @see RTTimerReleaseSystemGranularity, RTTimerGetSystemGranularity */ RTDECL(int) RTTimerRequestSystemGranularity(uint32_t u32Request, uint32_t *pu32Granted); /** * Releases a system timer granularity grant acquired by RTTimerRequestSystemGranularity(). * * @returns IPRT status code. * @retval VERR_NOT_SUPPORTED if the host platform doesn't have any way of modifying * the system timer granularity. * @retval VERR_WRONG_ORDER if nobody call RTTimerRequestSystemGranularity() with the * given grant value. * @param u32Granted The granted system granularity. * @see RTTimerRequestSystemGranularity */ RTDECL(int) RTTimerReleaseSystemGranularity(uint32_t u32Granted); /** @} */ __END_DECLS #endif