On 27.06.23 22:18, Kinsey Moore wrote:
diff --git a/c-user/task/directives.rst b/c-user/task/directives.rst
index c082b51..3334679 100644
--- a/c-user/task/directives.rst
+++ b/c-user/task/directives.rst
@@ -1475,15 +1475,15 @@ The following constraints apply to this directive:
\clearpage
.. index:: rtems_task_wake_after()
-.. index:: delay a task for an interval
-.. index:: wake up after an interval
+.. index:: delay a task for a number of ticks
+.. index:: wake up after a number of ticks
.. _InterfaceRtemsTaskWakeAfter:
rtems_task_wake_after()
-----------------------
-Wakes up after an interval in :term:`clock ticks <clock tick>` or yields the
+Wakes up after a number of :term:`clock ticks <clock tick>` or yields the
processor.
.. rubric:: CALLING SEQUENCE:
@@ -1502,10 +1502,12 @@ processor.
This directive blocks the calling task for the specified ``ticks`` of clock
ticks if the value is not equal to :c:macro:`RTEMS_YIELD_PROCESSOR`. When the
-requested interval has elapsed, the task is made ready. The clock tick
+requested number of ticks has elapsed, the task is made ready. The clock tick
directives automatically updates the delay period. The calling task may give
up the processor and remain in the ready state by specifying a value of
-:c:macro:`RTEMS_YIELD_PROCESSOR` in ``ticks``.
+:c:macro:`RTEMS_YIELD_PROCESSOR` in ``ticks``. Applications requiring use of a
+time base instead of system ticks should make use of ``nanosleep()`` or
+``clock_nanosleep()``.
What is a time base?
nanosleep() has the same issues as rtems_task_wake_after(). If you want
to wait for fixed intervals, then you have to use clock_nanosleep() with
TIMER_ABSTIME and CLOCK_MONOTONIC.
The wording with the interval is not really wrong. Only the clock
resolution is a bit coarse (clock ticks). I guess the real problem is
that if you want to implement a periodic task with
while (1) {
f();
rtems_task_wake_after(period);
}
then this doesn't work if the time between calls to
rtems_task_wake_after() varies within the range of clock ticks. This can
be fixed by using clock_nanosleep() with TIMER_ABSTIME and CLOCK_MONOTONIC.
.. rubric:: RETURN VALUES:
Could you please update
https://git.rtems.org/rtems-central/tree/spec/rtems/task/if/wake-after.yml
since this will keep also the Doxygen up to date.
For clock_nanosleep() references, use ${/c/if/clock-nanosleep:/name}.
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