timer.h revision 3e6c6998d1dfeded8b9a23f5aa94ad63e9a681d9
/** @file
* innotek Portable Runtime - Timer.
*/
/*
* Copyright (C) 2006-2007 innotek GmbH
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* 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.
*/
#ifndef ___iprt_timer_h
#define ___iprt_timer_h
/** @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. */
/**
* 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.
*/
/** 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.
* @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);
/** @name RTTimerCreateEx flags
* @{ */
/** Any CPU is fine. (Must be 0.) */
#define RTTIMER_FLAGS_CPU_ANY 0
/** One specific CPU */
/** All online CPUs. */
/** CPU mask. */
#define RTTIMER_FLAGS_CPU_MASK 0xff
/** Convert a CPU number (0-based) to RTTimerCreateEx flags.
* This will automatically OR in the RTTIMER_FLAG_CPU_SPECIFIC flag. */
/** Macro that validates the flags. */
#define RTTIMER_FLAGS_IS_VALID(fFlags) ( !((fFlags) & ((fFlags) & RTTIMER_FLAGS_CPU_SPECIFIC ? 0x1ff : 0x100)) )
/** @} */
/**
* Stops and destroys a running timer.
*
* @returns iprt status code.
* @param pTimer Timer to stop and destroy. NULL is ok.
*/
/**
* 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
*/
/**
* 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
*/
/**
* Gets the (current) timer granularity of the system.
*
* @returns The timer granularity of the system in nanoseconds.
* @see RTTimerRequestSystemGranularity
*/
/**
* 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
*/
/**
* 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
*/
/** @} */
#endif