Time types. More...

#include "FreeRTOS_POSIX/sys/types.h"
#include "FreeRTOS_POSIX/signal.h"

Data Structures
struct	timespec
	represents an elapsed time More...

struct	itimerspec
	timer More...

struct	tm
	calendar representation of time More...

Macros
Unit conversion constants.
#define	MICROSECONDS_PER_SECOND ( 1000000LL )

#define	NANOSECONDS_PER_SECOND ( 1000000000LL )

#define	NANOSECONDS_PER_TICK ( NANOSECONDS_PER_SECOND / configTICK_RATE_HZ )

Clock identifiers.
#define	CLOCK_REALTIME 0

#define	CLOCK_MONOTONIC 1

A number used to convert the value returned by the clock() function into seconds.
#define	CLOCKS_PER_SEC ( ( clock_t ) configTICK_RATE_HZ )

Flag indicating time is absolute.
For functions taking timer objects, this refers to the clock associated with the timer.
#define	TIMER_ABSTIME 0x01

Functions
clock_t	clock (void)
	Report CPU time used. More...

int	clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
	Access a process CPU-time clock. More...

int	clock_getres (clockid_t clock_id, struct timespec *res)
	Returns the resolution of a clock. More...

int	clock_gettime (clockid_t clock_id, struct timespec *tp)
	Returns the current value for the specified clock, clock_id. More...

int	clock_nanosleep (clockid_t clock_id, int flags, const struct timespec rqtp, struct timespec rmtp)
	High resolution sleep with specifiable clock. More...

int	clock_settime (clockid_t clock_id, const struct timespec *tp)
	Sets the time for the specified clock. More...

struct tm *	localtime_r (const time_t timer, struct tm result)
	Convert a time value to a broken-down local time. More...

int	nanosleep (const struct timespec rqtp, struct timespec rmtp)
	High resolution sleep. More...

size_t	strftime (char s, size_t maxsize, const char format, const struct tm *timeptr)
	Convert date and time to a string. More...

time_t	time (time_t *tloc)
	Get time. More...

int	timer_create (clockid_t clockid, struct sigevent evp, timer_t timerid)
	Create a per-process timer. More...

int	timer_delete (timer_t timerid)
	Delete a per-process timer. More...

int	timer_getoverrun (timer_t timerid)
	Get the timer overrun count. More...

int	timer_gettime (timer_t timerid, struct itimerspec *value)
	Get the amount of time until the timer expires. More...

int	timer_settime (timer_t timerid, int flags, const struct itimerspec value, struct itimerspec ovalue)
	Set the time until the next expiration of the timer. More...

Detailed Description

Time types.

http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/time.h.html

Macro Definition Documentation

◆ MICROSECONDS_PER_SECOND

#define MICROSECONDS_PER_SECOND ( 1000000LL )

Microseconds per second.

◆ NANOSECONDS_PER_SECOND

#define NANOSECONDS_PER_SECOND ( 1000000000LL )

Nanoseconds per second.

◆ NANOSECONDS_PER_TICK

#define NANOSECONDS_PER_TICK ( NANOSECONDS_PER_SECOND / configTICK_RATE_HZ )

Nanoseconds per FreeRTOS tick.

◆ CLOCK_REALTIME

#define CLOCK_REALTIME 0

The identifier of the system-wide clock measuring real time.

◆ CLOCK_MONOTONIC

#define CLOCK_MONOTONIC 1

The identifier for the system-wide monotonic clock.

Function Documentation

◆ clock()

clock_t clock ( void )

Report CPU time used.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/clock.html

Returns: The number of FreeRTOS ticks since the scheduler was started minus the ticks spent in the idle task.

Note: This function does NOT report the number of ticks spent by the calling thread.

◆ clock_getcpuclockid()

int clock_getcpuclockid	(	pid_t	pid,
		clockid_t *	clock_id
	)

Access a process CPU-time clock.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/clock_getcpuclockid.html

Return values

EPERM

Note: This function is currently unsupported.

◆ clock_getres()

int clock_getres	(	clockid_t	clock_id,
		struct timespec *	res
	)

Returns the resolution of a clock.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/clock_getres.html

Note: clock_id is ignored; This function stores the resolution of the FreeRTOS tick count in the object res points to.

Return values

0	- Upon successful execution

◆ clock_gettime()

int clock_gettime	(	clockid_t	clock_id,
		struct timespec *	tp
	)

Returns the current value for the specified clock, clock_id.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/clock_gettime.html

Note: clock_id is ignored; this function does not check for overflows of time_t.

Return values

0	- Upon successful completion.

◆ clock_nanosleep()

int clock_nanosleep	(	clockid_t	clock_id,
		int	flags,
		const struct timespec *	rqtp,
		struct timespec *	rmtp
	)

High resolution sleep with specifiable clock.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/clock_nanosleep.html

Note: clock_id is ignored, as this function uses the FreeRTOS tick count as its clock.; flags is ignored, if INCLUDE_vTaskDelayUntil is 0. i.e. the FreeRTOS function vTaskDelayUntil isn't available.; rmtp is also ignored, as signals are not implemented.

Return values

0	- Upon successful completion.
EINVAL	- The rqtp argument specified a nanosecond value less than zero or greater than or equal to 1000 million.

◆ clock_settime()

int clock_settime	(	clockid_t	clock_id,
		const struct timespec *	tp
	)

Sets the time for the specified clock.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/clock_settime.html

Return values

-1	with errno set to EPERM.

Note: This function is currently unsupported, as FreeRTOS does not provide a function to modify the tick count.

◆ localtime_r()

struct tm* localtime_r	(	const time_t *	timer,
		struct tm *	result
	)

Convert a time value to a broken-down local time.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/localtime_r.html

Note: timer is ignored; This function can only store the time as tm.tm_tick. All other members of the struct will be set to 0.; In order to store tm.tm_tick in result, posixconfgENABLE_TM needs to be set to 1. See FreeRTOS_POSIX_portable_default.h for porting configurations.

Returns: Upon successful completion, returns a pointer points to the object holding structure of type tm.; If any error, rutrns NULL, with errno set to ENOTSUP.

◆ nanosleep()

int nanosleep	(	const struct timespec *	rqtp,
		struct timespec *	rmtp
	)

High resolution sleep.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/nanosleep.html

Note: rmtp is ignored, as signals are not implemented.

Return values

0	- Upon successful completion.
-1	- The rqtp argument is invalid OR the rqtp argument specified a nanosecond value less than zero or greater than or equal to 1000 million.

◆ strftime()

size_t strftime	(	char *	s,
		size_t	maxsize,
		const char *	format,
		const struct tm *	timeptr
	)

Convert date and time to a string.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/strftime.html

Note: format is ignored.

Return values

the	number of bytes placed into the array pointed to by s, if the total number of resulting bytes including the terminating null byte is not more than maxsize.
0,otherwise.	In this case, the array pointed to by s contains partially copied data.

◆ time()

time_t time ( time_t * tloc )

Get time.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/time.html

Note: This function returns the FreeRTOS tick count, not the seconds since UNIX epoch.

Return values

FreeRTOS tick count - upon successful completion

◆ timer_create()

int timer_create	(	clockid_t	clockid,
		struct sigevent *	evp,
		timer_t *	timerid
	)

Create a per-process timer.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_create.html

Note: clock_id is ignored, as this function used the FreeRTOS tick count as its clock.; evp.sigev_notify must be set to SIGEV_THREAD, since signals are currently not supported.

Return values

0	- Upon successful completion, with location referenced by timerid updated.
-1	- If an error occurs. errno is also set.

Side Effects:: Possible errno values
ENOTSUP - If evp is NULL OR evp->sigen_notify == SIGEV_SIGNAL.
EAGAIN - The system lacks sufficient signal queuing resources to honor the request.

◆ timer_delete()

int timer_delete ( timer_t timerid )

Delete a per-process timer.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_delete.html

Return values

0	- Upon successful completion.

◆ timer_getoverrun()

int timer_getoverrun ( timer_t timerid )

Get the timer overrun count.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.html

Return values

0	- Always return 0, since signals are not supported.

◆ timer_gettime()

int timer_gettime	(	timer_t	timerid,
		struct itimerspec *	value
	)

Get the amount of time until the timer expires.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_gettime.html

Return values

0	- Upon successful completion.

◆ timer_settime()

int timer_settime	(	timer_t	timerid,
		int	flags,
		const struct itimerspec *	value,
		struct itimerspec *	ovalue
	)

Set the time until the next expiration of the timer.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_settime.html

Return values

0	- Upon successful completion.
-1	- An error occured, errno is also set.

Side Effects:: Possible errno values
EINVAL - A value structure specified a nanosecond value less than zero or greater than or equal to 1000 million, AND the it_value member of that structure did not specify zero seconds and nanoseconds.

Data Structures

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ MICROSECONDS_PER_SECOND

◆ NANOSECONDS_PER_SECOND

◆ NANOSECONDS_PER_TICK

◆ CLOCK_REALTIME

◆ CLOCK_MONOTONIC

Function Documentation

◆ clock()

◆ clock_getcpuclockid()

◆ clock_getres()

◆ clock_gettime()

◆ clock_nanosleep()

◆ clock_settime()

◆ localtime_r()

◆ nanosleep()

◆ strftime()

◆ time()

◆ timer_create()

◆ timer_delete()

◆ timer_getoverrun()

◆ timer_gettime()

◆ timer_settime()