Collaboration diagram for Virtual Timers:

Detailed Description

Time and Virtual Timers related APIs and services.

Functions
void	_vt_init (void)
	Virtual Timers initialization. More...

void	chVTDoSetI (virtual_timer_t vtp, sysinterval_t delay, vtfunc_t vtfunc, void par)
	Enables a virtual timer. More...

void	chVTDoResetI (virtual_timer_t *vtp)
	Disables a Virtual Timer. More...

static void	chVTObjectInit (virtual_timer_t *vtp)
	Initializes a `virtual_timer_t` object. More...

static systime_t	chVTGetSystemTimeX (void)
	Current system time. More...

static systime_t	chVTGetSystemTime (void)
	Current system time. More...

static sysinterval_t	chVTTimeElapsedSinceX (systime_t start)
	Returns the elapsed time since the specified start time. More...

static bool	chVTIsSystemTimeWithinX (systime_t start, systime_t end)
	Checks if the current system time is within the specified time window. More...

static bool	chVTIsSystemTimeWithin (systime_t start, systime_t end)
	Checks if the current system time is within the specified time window. More...

static bool	chVTGetTimersStateI (sysinterval_t *timep)
	Returns the time interval until the next timer event. More...

static bool	chVTIsArmedI (const virtual_timer_t *vtp)
	Returns `true` if the specified timer is armed. More...

static bool	chVTIsArmed (const virtual_timer_t *vtp)
	Returns `true` if the specified timer is armed. More...

static void	chVTResetI (virtual_timer_t *vtp)
	Disables a Virtual Timer. More...

static void	chVTReset (virtual_timer_t *vtp)
	Disables a Virtual Timer. More...

static void	chVTSetI (virtual_timer_t vtp, sysinterval_t delay, vtfunc_t vtfunc, void par)
	Enables a virtual timer. More...

static void	chVTSet (virtual_timer_t vtp, sysinterval_t delay, vtfunc_t vtfunc, void par)
	Enables a virtual timer. More...

static void	chVTDoTickI (void)
	Virtual timers ticker. More...

Function Documentation

void _vt_init ( void )

Virtual Timers initialization.

Note: Internal use only.

Function Class:: Not an API, this function is for internal use only.

Definition at line 61 of file chvt.c.

References ch, ch_virtual_timers_list::delta, ch_virtual_timers_list::lasttime, ch_virtual_timers_list::next, ch_virtual_timers_list::prev, ch_virtual_timers_list::systime, and ch_system::vtlist.

Referenced by chSysInit().

void chVTDoSetI	(	virtual_timer_t *	vtp,
		sysinterval_t	delay,
		vtfunc_t	vtfunc,
		void *	par
	)

Enables a virtual timer.

The timer is enabled and programmed to trigger after the delay specified as parameter.

Precondition: The timer must not be already armed before calling this function.

Note: The callback function is invoked from interrupt context.

Parameters

[out]	vtp	the `virtual_timer_t` structure pointer
[in]	delay	the number of ticks before the operation timeouts, the special values are handled as follow: TIME_INFINITE is allowed but interpreted as a normal time specification. TIME_IMMEDIATE this value is not allowed.
[in]	vtfunc	the timer callback function. After invoking the callback the timer is disabled and the structure can be disposed or reused.
[in]	par	a parameter that will be passed to the callback function

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 95 of file chvt.c.

References ch, CH_CFG_ST_TIMEDELTA, chDbgAssert, chDbgCheck, chDbgCheckClassI(), chTimeAddX(), chTimeDiffX(), chVTGetSystemTimeX(), ch_virtual_timer::delta, ch_virtual_timers_list::delta, ch_virtual_timer::func, ch_virtual_timers_list::lasttime, ch_virtual_timer::next, ch_virtual_timers_list::next, ch_virtual_timer::par, ch_virtual_timer::prev, ch_virtual_timers_list::prev, TIME_IMMEDIATE, TIME_MAX_SYSTIME, and ch_system::vtlist.

Referenced by chSchGoSleepTimeoutS(), and chVTSetI().

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void chVTDoResetI ( virtual_timer_t * vtp )

Disables a Virtual Timer.

Precondition: The timer must be in armed state before calling this function.

Parameters

[in] vtp the virtual_timer_t structure pointer

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 211 of file chvt.c.

References ch, CH_CFG_ST_TIMEDELTA, chDbgAssert, chDbgCheck, chDbgCheckClassI(), chTimeAddX(), chTimeDiffX(), chVTGetSystemTimeX(), ch_virtual_timer::delta, ch_virtual_timers_list::delta, ch_virtual_timer::func, ch_virtual_timers_list::lasttime, ch_virtual_timer::next, ch_virtual_timers_list::next, ch_virtual_timer::prev, TIME_MAX_SYSTIME, and ch_system::vtlist.

Referenced by chSchGoSleepTimeoutS(), and chVTResetI().

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static void chVTObjectInit ( virtual_timer_t * vtp )

inlinestatic

Initializes a virtual_timer_t object.

Note: Initializing a timer object is not strictly required because the function chVTSetI() initializes the object too. This function is only useful if you need to perform a chVTIsArmed() check before calling chVTSetI().

Parameters

[out] vtp the virtual_timer_t structure pointer

Function Class:: Initializer, this function just initializes an object and can be invoked before the kernel is initialized.

Definition at line 97 of file chvt.h.

References ch_virtual_timer::func.

static systime_t chVTGetSystemTimeX ( void )

inlinestatic

Current system time.

Returns the number of system ticks since the chSysInit() invocation.

Note: The counter can reach its maximum and then restart from zero.; This function can be called from any context but its atomicity is not guaranteed on architectures whose word size is less than systime_t size.

Returns: The system time in ticks.

Function Class:: This is an X-Class API, this function can be invoked from any context.

Definition at line 115 of file chvt.h.

References ch, ch_virtual_timers_list::systime, and ch_system::vtlist.

Referenced by chThdSleepUntil(), chThdSleepUntilWindowed(), chVTDoResetI(), chVTDoSetI(), chVTDoTickI(), chVTGetSystemTime(), chVTGetTimersStateI(), chVTIsSystemTimeWithinX(), chVTTimeElapsedSinceX(), and trace_next().

static systime_t chVTGetSystemTime ( void )

inlinestatic

Current system time.

Returns the number of system ticks since the chSysInit() invocation.

Note: The counter can reach its maximum and then restart from zero.

Returns: The system time in ticks.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 134 of file chvt.h.

References chSysLock(), chSysUnlock(), and chVTGetSystemTimeX().

Referenced by chVTIsSystemTimeWithin().

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static sysinterval_t chVTTimeElapsedSinceX ( systime_t start )

inlinestatic

Returns the elapsed time since the specified start time.

Parameters

[in] start start time

Returns: The elapsed time.

Function Class:: This is an X-Class API, this function can be invoked from any context.

Definition at line 152 of file chvt.h.

References chTimeDiffX(), and chVTGetSystemTimeX().

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static bool chVTIsSystemTimeWithinX	(	systime_t	start,
		systime_t	end
	)

inlinestatic

Checks if the current system time is within the specified time window.

Note: When start==end then the function returns always true because the whole time range is specified.

Parameters

[in]	start	the start of the time window (inclusive)
[in]	end	the end of the time window (non inclusive)

Return values

true	current time within the specified time window.
false	current time not within the specified time window.

Function Class:: This is an X-Class API, this function can be invoked from any context.

Definition at line 170 of file chvt.h.

References chTimeIsInRangeX(), and chVTGetSystemTimeX().

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static bool chVTIsSystemTimeWithin	(	systime_t	start,
		systime_t	end
	)

inlinestatic

Checks if the current system time is within the specified time window.

Note: When start==end then the function returns always true because the whole time range is specified.

Parameters

[in]	start	the start of the time window (inclusive)
[in]	end	the end of the time window (non inclusive)

Return values

true	current time within the specified time window.
false	current time not within the specified time window.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 188 of file chvt.h.

References chTimeIsInRangeX(), and chVTGetSystemTime().

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static bool chVTGetTimersStateI ( sysinterval_t * timep )

inlinestatic

Returns the time interval until the next timer event.

Note: The return value is not perfectly accurate and can report values in excess of CH_CFG_ST_TIMEDELTA ticks.; The interval returned by this function is only meaningful if more timers are not added to the list until the returned time.

Parameters

[out] timep pointer to a variable that will contain the time interval until the next timer elapses. This pointer can be NULL if the information is not required.

Returns: The time, in ticks, until next time event.

Return values

false	if the timers list is empty.
true	if the timers list contains at least one timer.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 209 of file chvt.h.

References ch, CH_CFG_ST_TIMEDELTA, chDbgCheckClassI(), chTimeAddX(), chTimeDiffX(), chVTGetSystemTimeX(), ch_virtual_timer::delta, ch_virtual_timers_list::lasttime, ch_virtual_timers_list::next, and ch_system::vtlist.

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static bool chVTIsArmedI ( const virtual_timer_t * vtp )

inlinestatic

Returns true if the specified timer is armed.

Precondition: The timer must have been initialized using chVTObjectInit() or chVTDoSetI().

Parameters

[in] vtp the virtual_timer_t structure pointer

Returns: true if the timer is armed.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 241 of file chvt.h.

References chDbgCheckClassI(), and ch_virtual_timer::func.

Referenced by chSchGoSleepTimeoutS(), chVTIsArmed(), and chVTResetI().

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static bool chVTIsArmed ( const virtual_timer_t * vtp )

inlinestatic

Returns true if the specified timer is armed.

Precondition: The timer must have been initialized using chVTObjectInit() or chVTDoSetI().

Parameters

[in] vtp the virtual_timer_t structure pointer

Returns: true if the timer is armed.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 258 of file chvt.h.

References chSysLock(), chSysUnlock(), and chVTIsArmedI().

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static void chVTResetI ( virtual_timer_t * vtp )

inlinestatic

Disables a Virtual Timer.

Note: The timer is first checked and disabled only if armed.

Precondition: The timer must have been initialized using chVTObjectInit() or chVTDoSetI().

Parameters

[in] vtp the virtual_timer_t structure pointer

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 278 of file chvt.h.

References chVTDoResetI(), and chVTIsArmedI().

Referenced by chVTReset(), and chVTSetI().

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static void chVTReset ( virtual_timer_t * vtp )

inlinestatic

Disables a Virtual Timer.

Note: The timer is first checked and disabled only if armed.

Precondition: The timer must have been initialized using chVTObjectInit() or chVTDoSetI().

Parameters

[in] vtp the virtual_timer_t structure pointer

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 295 of file chvt.h.

References chSysLock(), chSysUnlock(), and chVTResetI().

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static void chVTSetI	(	virtual_timer_t *	vtp,
		sysinterval_t	delay,
		vtfunc_t	vtfunc,
		void *	par
	)

inlinestatic

Enables a virtual timer.

If the virtual timer was already enabled then it is re-enabled using the new parameters.

Precondition: The timer must have been initialized using chVTObjectInit() or chVTDoSetI().

Parameters

[in]	vtp	the `virtual_timer_t` structure pointer
[in]	delay	the number of ticks before the operation timeouts, the special values are handled as follow: TIME_INFINITE is allowed but interpreted as a normal time specification. TIME_IMMEDIATE this value is not allowed.
[in]	vtfunc	the timer callback function. After invoking the callback the timer is disabled and the structure can be disposed or reused.
[in]	par	a parameter that will be passed to the callback function

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 324 of file chvt.h.

References chVTDoSetI(), and chVTResetI().

Referenced by chVTSet().

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static void chVTSet	(	virtual_timer_t *	vtp,
		sysinterval_t	delay,
		vtfunc_t	vtfunc,
		void *	par
	)

inlinestatic

Enables a virtual timer.

If the virtual timer was already enabled then it is re-enabled using the new parameters.

Precondition: The timer must have been initialized using chVTObjectInit() or chVTDoSetI().

Parameters

[in]	vtp	the `virtual_timer_t` structure pointer
[in]	delay	the number of ticks before the operation timeouts, the special values are handled as follow: TIME_INFINITE is allowed but interpreted as a normal time specification. TIME_IMMEDIATE this value is not allowed.
[in]	vtfunc	the timer callback function. After invoking the callback the timer is disabled and the structure can be disposed or reused.
[in]	par	a parameter that will be passed to the callback function

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 353 of file chvt.h.

References chSysLock(), chSysUnlock(), and chVTSetI().

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static void chVTDoTickI ( void )

inlinestatic

Virtual timers ticker.

Note: The system lock is released before entering the callback and re-acquired immediately after. It is callback's responsibility to acquire the lock if needed. This is done in order to reduce interrupts jitter when many timers are in use.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 370 of file chvt.h.

References ch, CH_CFG_ST_TIMEDELTA, chDbgAssert, chDbgCheckClassI(), chSysLockFromISR(), chSysUnlockFromISR(), chTimeAddX(), chTimeDiffX(), chVTGetSystemTimeX(), ch_virtual_timer::delta, ch_virtual_timer::func, ch_virtual_timers_list::lasttime, ch_virtual_timer::next, ch_virtual_timers_list::next, ch_virtual_timer::par, ch_virtual_timer::prev, ch_virtual_timers_list::systime, TIME_MAX_SYSTIME, and ch_system::vtlist.

Referenced by chSysTimerHandlerI().

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Detailed Description

Functions

Function Documentation