RTEMS 6.1-rc2
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Macros | Functions
Clock Manager

The Clock Manager provides support for time of day and other time related capabilities. More...

Macros

#define rtems_clock_get_ticks_per_second(void)   _Watchdog_Ticks_per_second
 Gets the number of clock ticks per second configured for the application.
 
#define rtems_clock_get_ticks_since_boot(void)   _Watchdog_Ticks_since_boot
 Gets the number of clock ticks since some time point during the system initialization or the last overflow of the clock tick counter.
 

Functions

rtems_status_code rtems_clock_set (const rtems_time_of_day *time_of_day)
 Sets the CLOCK_REALTIME to the time of day.
 
rtems_status_code rtems_clock_get_tod (rtems_time_of_day *time_of_day)
 Gets the time of day associated with the current CLOCK_REALTIME.
 
rtems_status_code rtems_clock_get_tod_timeval (struct timeval *time_of_day)
 Gets the seconds and microseconds elapsed since the Unix epoch and the current CLOCK_REALTIME.
 
void rtems_clock_get_realtime (struct timespec *time_snapshot)
 Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in seconds and nanoseconds format.
 
void rtems_clock_get_realtime_bintime (struct bintime *time_snapshot)
 Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in binary time format.
 
void rtems_clock_get_realtime_timeval (struct timeval *time_snapshot)
 Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in seconds and microseconds format.
 
void rtems_clock_get_realtime_coarse (struct timespec *time_snapshot)
 Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in coarse resolution in seconds and nanoseconds format.
 
void rtems_clock_get_realtime_coarse_bintime (struct bintime *time_snapshot)
 Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in coarse resolution in binary time format.
 
void rtems_clock_get_realtime_coarse_timeval (struct timeval *time_snapshot)
 Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in coarse resolution in seconds and microseconds format.
 
void rtems_clock_get_monotonic (struct timespec *time_snapshot)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in seconds and nanoseconds format.
 
void rtems_clock_get_monotonic_bintime (struct bintime *time_snapshot)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in binary time format.
 
int64_t rtems_clock_get_monotonic_sbintime (void)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in signed binary time format.
 
void rtems_clock_get_monotonic_timeval (struct timeval *time_snapshot)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in seconds and microseconds format.
 
void rtems_clock_get_monotonic_coarse (struct timespec *time_snapshot)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in coarse resolution in seconds and nanoseconds format.
 
void rtems_clock_get_monotonic_coarse_bintime (struct bintime *time_snapshot)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in coarse resolution in binary time format.
 
void rtems_clock_get_monotonic_coarse_timeval (struct timeval *time_snapshot)
 Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in coarse resolution in seconds and microseconds format.
 
void rtems_clock_get_boot_time (struct timespec *boot_time)
 Gets the time elapsed since the Unix epoch at some time point during system initialization in seconds and nanoseconds format.
 
void rtems_clock_get_boot_time_bintime (struct bintime *boot_time)
 Gets the time elapsed since the Unix epoch at some time point during system initialization in binary time format.
 
void rtems_clock_get_boot_time_timeval (struct timeval *boot_time)
 Gets the time elapsed since the Unix epoch at some time point during system initialization in seconds and microseconds format.
 
rtems_status_code rtems_clock_get_seconds_since_epoch (rtems_interval *seconds_since_rtems_epoch)
 Gets the seconds elapsed since the RTEMS epoch and the current CLOCK_REALTIME.
 
rtems_status_code rtems_clock_get_uptime (struct timespec *uptime)
 Gets the seconds and nanoseconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.
 
void rtems_clock_get_uptime_timeval (struct timeval *uptime)
 Gets the seconds and microseconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.
 
time_t rtems_clock_get_uptime_seconds (void)
 Gets the seconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.
 
uint64_t rtems_clock_get_uptime_nanoseconds (void)
 Gets the nanoseconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.
 

Detailed Description

The Clock Manager provides support for time of day and other time related capabilities.

Macro Definition Documentation

◆ rtems_clock_get_ticks_per_second

rtems_interval rtems_clock_get_ticks_per_second (   void)    _Watchdog_Ticks_per_second

Gets the number of clock ticks per second configured for the application.

Returns
Returns the number of clock ticks per second configured for this application.
Notes
The number of clock ticks per second is defined indirectly by the CONFIGURE_MICROSECONDS_PER_TICK configuration option.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.

◆ rtems_clock_get_ticks_since_boot

rtems_interval rtems_clock_get_ticks_since_boot (   void)    _Watchdog_Ticks_since_boot

Gets the number of clock ticks since some time point during the system initialization or the last overflow of the clock tick counter.

Returns
Returns the number of clock ticks since some time point during the system initialization or the last overflow of the clock tick counter.
Notes
With a 1ms clock tick, this counter overflows after 50 days since boot. This is the historical measure of uptime in an RTEMS system. The newer service rtems_clock_get_uptime() is another and potentially more accurate way of obtaining similar information.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.

Function Documentation

◆ rtems_clock_get_boot_time()

void rtems_clock_get_boot_time ( struct timespec *  boot_time)

Gets the time elapsed since the Unix epoch at some time point during system initialization in seconds and nanoseconds format.

Parameters
[out]boot_timeis the pointer to a struct timespec object. The time elapsed since the Unix epoch at some time point during system initialization call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes
See rtems_clock_get_boot_time_bintime() and rtems_clock_get_boot_time_timeval() to get the boot time in alternative formats. Setting the CLOCK_REALTIME will also set the boot time.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_boot_time_bintime()

void rtems_clock_get_boot_time_bintime ( struct bintime *  boot_time)

Gets the time elapsed since the Unix epoch at some time point during system initialization in binary time format.

Parameters
[out]boot_timeis the pointer to a bintime object. The time elapsed since the Unix epoch at some time point during system initialization call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes
See rtems_clock_get_boot_time() and rtems_clock_get_boot_time_timeval() to get the boot time in alternative formats. Setting the CLOCK_REALTIME will also set the boot time.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_boot_time_timeval()

void rtems_clock_get_boot_time_timeval ( struct timeval *  boot_time)

Gets the time elapsed since the Unix epoch at some time point during system initialization in seconds and microseconds format.

Parameters
[out]boot_timeis the pointer to a struct timeval object. The time elapsed since the Unix epoch at some time point during system initialization call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes
See rtems_clock_get_boot_time() and rtems_clock_get_boot_time_bintime() to get the boot time in alternative formats. Setting the CLOCK_REALTIME will also set the boot time.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic()

void rtems_clock_get_monotonic ( struct timespec *  time_snapshot)

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in seconds and nanoseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timespec object. The time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point during the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system. Alternatively, the rtems_clock_get_monotonic_coarse() directive may be used to get the time with in a lower resolution and with less runtime overhead.

See rtems_clock_get_monotonic_bintime(), rtems_clock_get_monotonic_sbintime(), and rtems_clock_get_monotonic_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic_bintime()

void rtems_clock_get_monotonic_bintime ( struct bintime *  time_snapshot)

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in binary time format.

Parameters
[out]time_snapshotis the pointer to a bintime object. The time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point during the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system. Alternatively, the rtems_clock_get_monotonic_coarse_bintime() directive may be used to get the time in a lower resolution and with less runtime overhead.

See rtems_clock_get_monotonic(), rtems_clock_get_monotonic_sbintime(), and rtems_clock_get_monotonic_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic_coarse()

void rtems_clock_get_monotonic_coarse ( struct timespec *  time_snapshot)

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in coarse resolution in seconds and nanoseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timespec object. The time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point close to the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive does not access a device to get the time. It uses a recent snapshot provided by the Clock Driver. Alternatively, the rtems_clock_get_monotonic() directive may be used to get the time in a higher resolution and with a higher runtime overhead.

See rtems_clock_get_monotonic_coarse_bintime() and rtems_clock_get_monotonic_coarse_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic_coarse_bintime()

void rtems_clock_get_monotonic_coarse_bintime ( struct bintime *  time_snapshot)

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in coarse resolution in binary time format.

Parameters
[out]time_snapshotis the pointer to a bintime object. The time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point close to the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive does not access a device to get the time. It uses a recent snapshot provided by the Clock Driver. Alternatively, the rtems_clock_get_monotonic_bintime() directive may be used to get the time in a higher resolution and with a higher runtime overhead.

See rtems_clock_get_monotonic_coarse() and rtems_clock_get_monotonic_coarse_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic_coarse_timeval()

void rtems_clock_get_monotonic_coarse_timeval ( struct timeval *  time_snapshot)

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in coarse resolution in seconds and microseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timeval object. The time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point close to the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive does not access a device to get the time. It uses a recent snapshot provided by the Clock Driver. Alternatively, the rtems_clock_get_monotonic_timeval() directive may be used to get the time in a higher resolution and with a higher runtime overhead.

See rtems_clock_get_monotonic_coarse() and rtems_clock_get_monotonic_coarse_bintime() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic_sbintime()

int64_t rtems_clock_get_monotonic_sbintime ( void  )

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in signed binary time format.

Returns
Returns the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point during the directive call.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system.

See rtems_clock_get_monotonic(), rtems_clock_get_monotonic_bintime(), and rtems_clock_get_monotonic_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_monotonic_timeval()

void rtems_clock_get_monotonic_timeval ( struct timeval *  time_snapshot)

Gets the time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC in seconds and microseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timeval object. The time elapsed since some fixed time point in the past measured using the CLOCK_MONOTONIC at some time point during the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system. Alternatively, the rtems_clock_get_monotonic_coarse_timeval() directive may be used to get the time in a lower resolution and with less runtime overhead.

See rtems_clock_get_monotonic(), rtems_clock_get_monotonic_bintime(), and rtems_clock_get_monotonic_sbintime() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_realtime()

void rtems_clock_get_realtime ( struct timespec *  time_snapshot)

Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in seconds and nanoseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timespec object. The time elapsed since the Unix epoch measured using the CLOCK_REALTIME at some time point during the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system. Alternatively, the rtems_clock_get_realtime_coarse() directive may be used to get the time in a lower resolution and with less runtime overhead.

See rtems_clock_get_realtime_bintime() and rtems_clock_get_realtime_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_realtime_bintime()

void rtems_clock_get_realtime_bintime ( struct bintime *  time_snapshot)

Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in binary time format.

Parameters
[out]time_snapshotis the pointer to a bintime object. The time elapsed since the Unix epoch measured using the CLOCK_REALTIME at some time point during the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system. Alternatively, the rtems_clock_get_realtime_coarse_bintime() directive may be used to get the time in a lower resolution and with less runtime overhead.

See rtems_clock_get_realtime() and rtems_clock_get_realtime_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_realtime_coarse()

void rtems_clock_get_realtime_coarse ( struct timespec *  time_snapshot)

Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in coarse resolution in seconds and nanoseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timespec object. The time elapsed since the Unix epoch measured using the CLOCK_REALTIME at some time point close to the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive does not access a device to get the time. It uses a recent snapshot provided by the Clock Driver. Alternatively, the rtems_clock_get_realtime() directive may be used to get the time in a higher resolution and with a higher runtime overhead.

See rtems_clock_get_realtime_coarse_bintime() and rtems_clock_get_realtime_coarse_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_realtime_coarse_bintime()

void rtems_clock_get_realtime_coarse_bintime ( struct bintime *  time_snapshot)

Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in coarse resolution in binary time format.

Parameters
[out]time_snapshotis the pointer to a bintime object. The time elapsed since the Unix epoch measured using the CLOCK_REALTIME at some time point close to the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive does not access a device to get the time. It uses a recent snapshot provided by the Clock Driver. Alternatively, the rtems_clock_get_realtime_bintime() directive may be used to get the time in a higher resolution and with a higher runtime overhead.

See rtems_clock_get_realtime_coarse() and rtems_clock_get_realtime_coarse_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_realtime_coarse_timeval()

void rtems_clock_get_realtime_coarse_timeval ( struct timeval *  time_snapshot)

Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in coarse resolution in seconds and microseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timeval object. The time elapsed since the Unix epoch measured using the CLOCK_REALTIME at some time point close to the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive does not access a device to get the time. It uses a recent snapshot provided by the Clock Driver. Alternatively, the rtems_clock_get_realtime_timeval() directive may be used to get the time in a higher resolution and with a higher runtime overhead.

See rtems_clock_get_realtime_coarse() and rtems_clock_get_realtime_coarse_timeval() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_realtime_timeval()

void rtems_clock_get_realtime_timeval ( struct timeval *  time_snapshot)

Gets the time elapsed since the Unix epoch measured using CLOCK_REALTIME in seconds and microseconds format.

Parameters
[out]time_snapshotis the pointer to a struct timeval object. The time elapsed since the Unix epoch measured using the CLOCK_REALTIME at some time point during the directive call will be stored in this object. Calling the directive with a pointer equal to NULL is undefined behaviour.
Notes

The directive accesses a device provided by the Clock Driver to get the time in the highest resolution available to the system. Alternatively, the rtems_clock_get_realtime_coarse_timeval() directive may be used to get the time in a lower resolution and with less runtime overhead.

See rtems_clock_get_realtime() and rtems_clock_get_realtime_bintime() to get the time in alternative formats.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_seconds_since_epoch()

rtems_status_code rtems_clock_get_seconds_since_epoch ( rtems_interval seconds_since_rtems_epoch)

Gets the seconds elapsed since the RTEMS epoch and the current CLOCK_REALTIME.

Parameters
[out]seconds_since_rtems_epochis the pointer to an rtems_interval object. When the directive call is successful, the seconds elapsed since the RTEMS epoch and the CLOCK_REALTIME at some point during the directive call will be stored in this object.
Return values
RTEMS_SUCCESSFULThe requested operation was successful.
RTEMS_INVALID_ADDRESSThe seconds_since_rtems_epoch parameter was NULL.
RTEMS_NOT_DEFINEDThe CLOCK_REALTIME was not set. It can be set with rtems_clock_set().
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_tod()

rtems_status_code rtems_clock_get_tod ( rtems_time_of_day time_of_day)

Gets the time of day associated with the current CLOCK_REALTIME.

Parameters
time_of_dayis the pointer to an rtems_time_of_day object. When the directive call is successful, the time of day associated with the CLOCK_REALTIME at some point during the directive call will be stored in this object.
Return values
RTEMS_SUCCESSFULThe requested operation was successful.
RTEMS_INVALID_ADDRESSThe time_of_day parameter was NULL.
RTEMS_NOT_DEFINEDThe CLOCK_REALTIME was not set. It can be set with rtems_clock_set().
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_tod_timeval()

rtems_status_code rtems_clock_get_tod_timeval ( struct timeval *  time_of_day)

Gets the seconds and microseconds elapsed since the Unix epoch and the current CLOCK_REALTIME.

Parameters
[out]time_of_dayis the pointer to a struct timeval object. When the directive call is successful, the seconds and microseconds elapsed since the Unix epoch and the CLOCK_REALTIME at some point during the directive call will be stored in this object.
Return values
RTEMS_SUCCESSFULThe requested operation was successful.
RTEMS_INVALID_ADDRESSThe time_of_day parameter was NULL.
RTEMS_NOT_DEFINEDThe CLOCK_REALTIME was not set. It can be set with rtems_clock_set().
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_uptime()

rtems_status_code rtems_clock_get_uptime ( struct timespec *  uptime)

Gets the seconds and nanoseconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.

Parameters
[out]uptimeis the pointer to a struct timespec object. When the directive call is successful, the seconds and nanoseconds elapsed since some time point during the system initialization and some point during the directive call using CLOCK_MONOTONIC will be stored in this object.
Return values
RTEMS_SUCCESSFULThe requested operation was successful.
RTEMS_INVALID_ADDRESSThe uptime parameter was NULL.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_uptime_nanoseconds()

uint64_t rtems_clock_get_uptime_nanoseconds ( void  )

Gets the nanoseconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.

Returns
Returns the nanoseconds elapsed since some time point during the system initialization and some point during the directive call using CLOCK_MONOTONIC.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_uptime_seconds()

time_t rtems_clock_get_uptime_seconds ( void  )

Gets the seconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.

Returns
Returns the seconds elapsed since some time point during the system initialization and some point during the directive call using CLOCK_MONOTONIC.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_get_uptime_timeval()

void rtems_clock_get_uptime_timeval ( struct timeval *  uptime)

Gets the seconds and microseconds elapsed since some time point during the system initialization using CLOCK_MONOTONIC.

Parameters
[out]uptimeis the pointer to a struct timeval object. The seconds and microseconds elapsed since some time point during the system initialization and some point during the directive call using CLOCK_MONOTONIC will be stored in this object. The pointer shall be valid, otherwise the behaviour is undefined.
Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive will not cause the calling task to be preempted.
  • The directive requires a Clock Driver.

◆ rtems_clock_set()

rtems_status_code rtems_clock_set ( const rtems_time_of_day time_of_day)

Sets the CLOCK_REALTIME to the time of day.

Parameters
time_of_dayis the time of day to set the clock.
Return values
RTEMS_SUCCESSFULThe requested operation was successful.
RTEMS_INVALID_ADDRESSThe time_of_day parameter was NULL.
RTEMS_INVALID_CLOCKThe time of day specified by time_of_day was invalid.
Notes

The date, time, and ticks specified by time_of_day are all range-checked, and an error is returned if any one is out of its valid range.

RTEMS can represent time points of the CLOCK_REALTIME clock in nanoseconds ranging from 1988-01-01T00:00:00.000000000Z to 2514-05-31T01:53:03.999999999Z. The future uptime of the system shall be in this range, otherwise the system behaviour is undefined. Due to implementation constraints, the time of day set by the directive shall be before 2100-01-01:00:00.000000000Z. The latest valid time of day accepted by the POSIX clock_settime() is 2400-01-01T00:00:00.999999999Z.

The specified time is based on the configured clock tick rate, see the CONFIGURE_MICROSECONDS_PER_TICK application configuration option.

Setting the time forward will fire all CLOCK_REALTIME timers which are scheduled at a time point before or at the time set by the directive. This may unblock tasks, which may preempt the calling task. User-provided timer routines will execute in the context of the caller.

It is allowed to call this directive from within interrupt context, however, this is not recommended since an arbitrary number of timers may fire.

The directive shall be called at least once to enable the service of CLOCK_REALTIME related directives. If the clock is not set at least once, they may return an error status.

Constraints

The following constraints apply to this directive:

  • The directive may be called from within any runtime context.
  • The directive may change the priority of a task. This may cause the calling task to be preempted.
  • The directive may unblock a task. This may cause the calling task to be preempted.
  • The time of day set by the directive shall be 1988-01-01T00:00:00.000000000Z or later.
  • The time of day set by the directive shall be before 2100-01-01T00:00:00.000000000Z.