Clock Services
[Driver Development API]

Collaboration diagram for Clock Services:

Functions
nanosecs_abs_t	rtdm_clock_read (void)
nanosecs_abs_t	rtdm_clock_read_monotonic (void)

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Function Documentation

nanosecs_abs_t rtdm_clock_read

(

void

)

Get system time

Returns:

The system time in nanoseconds is returned

Note:

The resolution of this service depends on the system timer. In particular, if the system timer is running in periodic mode, the return value will be limited to multiples of the timer tick period.

The system timer may have to be started to obtain valid results. Whether this happens automatically (as on Xenomai) or is controlled by the application depends on the RTDM host environment.

Environments:

This service can be called from:

• Kernel module initialization/cleanup code
• Interrupt service routine
• Kernel-based task
• User-space task (RT, non-RT)

Rescheduling: never.

nanosecs_abs_t rtdm_clock_read_monotonic

(

void

)

Get monotonic time

Returns:

The monotonic time in nanoseconds is returned

Note:

The resolution of this service depends on the system timer. In particular, if the system timer is running in periodic mode, the return value will be limited to multiples of the timer tick period.

The system timer may have to be started to obtain valid results. Whether this happens automatically (as on Xenomai) or is controlled by the application depends on the RTDM host environment.

Environments:

This service can be called from:

• Kernel module initialization/cleanup code
• Interrupt service routine
• Kernel-based task
• User-space task (RT, non-RT)

Rescheduling: never.

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