c-user: Document rtems_scheduler_get_processor()

Close #3731.

1 files changed, 31 insertions, 0 deletions

diff --git a/c-user/scheduling_concepts.rst b/c-user/scheduling_concepts.rst
index db90ed1..ad955f8 100644
--- a/c-user/scheduling_concepts.rst
+++ b/c-user/scheduling_concepts.rst
@@ -37,6 +37,8 @@ The directives provided by the scheduler manager are:
 
 - rtems_scheduler_get_maximum_priority_ - Get maximum task priority of a scheduler
 
+- rtems_scheduler_get_processor_ - Get current processor index
+
 - rtems_scheduler_get_processor_set_ - Get processor set of a scheduler
 
 - rtems_scheduler_add_processor_ - Add processor to a scheduler
@@ -697,6 +699,35 @@ NOTES:
 
    \clearpage
 
+.. _rtems_scheduler_get_processor:
+
+SCHEDULER_GET_PROCESSOR - Get current processor index
+-----------------------------------------------------
+
+CALLING SEQUENCE:
+    .. code-block:: c
+
+        uint32_t rtems_scheduler_get_processor( void );
+
+DIRECTIVE STATUS CODES:
+    This directive returns the index of the current processor.
+
+DESCRIPTION:
+    In uniprocessor configurations, a value of zero will be returned.
+
+    In SMP configurations, an architecture specific method is used to obtain the
+    index of the current processor in the system.  The set of processor indices
+    is the range of integers starting with zero up to the processor count minus
+    one.
+
+    Outside of sections with disabled thread dispatching the current processor
+    index may change after every instruction since the thread may migrate from
+    one processor to another.  Sections with disabled interrupts are sections
+    with thread dispatching disabled.
+
+NOTES:
+    None.
+
 .. _rtems_scheduler_get_processor_set:
 
 SCHEDULER_GET_PROCESSOR_SET - Get processor set of a scheduler