user: Mention replacements for removed APIs

user/migration/v5-to-v6.rst

@@ -18,3 +18,54 @@ default.  Code bases which never used this option before may observe now
 multiple definition linker errors.  For example, if global variables are
 declared and defined in header files (usually a missing ``extern`` in the header
 file).
+
+Replacements for Removed APIs
+-----------------------------
+
+* The ``rtems_iterate_over_all_threads()`` directive was removed. Use
+  ``rtems_task_iterate()`` instead.
+
+* The ``rtems_get_current_processor()`` directive was removed. Use
+  ``rtems_scheduler_get_processor()`` instead.
+
+* The ``rtems_get_processor_count()`` directive was removed. Use
+  ``rtems_scheduler_get_processor_maximum()`` instead.
+
+* The ``boolean`` type was removed. Use ``bool`` instead.
+
+* The ``single_precision`` type was removed. Use ``float`` instead.
+
+* The ``double_precision`` type was removed. Use ``double`` instead.
+
+* The ``proc_ptr`` type was removed. Use a proper function pointer type.
+
+* The ``rtems_context`` type was removed.  If you need this type in your
+  applications, please ask on the :r:list:`devel`.
+
+* The ``rtems_context_fp`` type was removed.  If you need this type in your
+  applications, please ask on the :r:list:`devel`.
+
+* The ``rtems_extension`` type was removed.  Use ``void`` instead.
+
+* The ``rtems_io_lookup_name()`` directive was removed. Use ``stat()`` instead.
+
+* The ``region_information_block`` type was removed. Use
+  ``Heap_Information_block`` instead.
+
+* The ``rtems_thread_cpu_usage_t`` type was removed. Use ``struct timespec``
+  instead.
+
+* The ``rtems_rate_monotonic_period_time_t`` type was removed. Use ``struct
+  timespec`` instead.
+
+* The ``_Copyright_Notice`` constant was removed from the API. Use
+  ``rtems_get_copyright_notice()`` instead.
+
+* The ``_RTEMS_version`` constant was removed from the API. Use
+  ``rtems_get_version_string()`` instead.
+
+* The ``RTEMS_MAXIMUM_NAME_LENGTH`` define was removed. Use
+  ``sizeof( rtems_name )`` instead.
+
+* The ``<rtems/system.h>`` header file was removed. Include ``<rtems.h>``
+  instead.