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+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the number of bytes reserved
+  for message queue buffers in the RTEMS Workspace.
+enabled-by: true
+index-entries:
+- configure message queue buffer memory
+- CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE
+- memory for a single message queue's buffers
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MESSAGE_BUFFER_MEMORY
+notes: |
+  The configuration options ${max-message-queues:/name} and
+  ${max-posix-message-queues:/name} define only how many message
+  queues can be created by the application.  The memory for the message
+  buffers is configured by this option.  For each message queue you have to
+  reserve some memory for the message buffers.  The size depends on the
+  maximum number of pending messages and the maximum size of the messages of
+  a message queue.  Use the ``CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE()`` macro
+  to specify the message buffer memory for each message queue and sum them up
+  to define the value for ``CONFIGURE_MAXIMUM_MESSAGE_QUEUES``.
+
+  The interface for the ``CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE()`` help
+  macro is as follows:
+
+  .. code-block:: c
+
+      CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE( max_messages, max_msg_size )
+
+  Where ``max_messages`` is the maximum number of pending messages and
+  ``max_msg_size`` is the maximum size in bytes of the messages of the
+  corresponding message queue.  Both parameters shall be compile time
+  constants.  Not using this help macro (e.g. just using
+  ``max_messages * max_msg_size``) may result in an underestimate of the
+  RTEMS Workspace size.
+
+  The following example illustrates how the
+  ``CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE()`` help macro can be used to assist in
+  calculating the message buffer memory required.  In this example, there are
+  two message queues used in this application.  The first message queue has a
+  maximum of 24 pending messages with the message structure defined by the
+  type ``one_message_type``.  The other message queue has a maximum of 500
+  pending messages with the message structure defined by the type
+  ``other_message_type``.
+
+  .. code-block:: c
+
+      #define CONFIGURE_MESSAGE_BUFFER_MEMORY ( \
+          CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE( \
+            24, \
+            sizeof( one_message_type ) \
+          ) \
+          + CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE( \
+            500, \
+            sizeof( other_message_type ) \
+          ) \
+        )
+text: ''
+type: interface