RTEMS Ada User's Guide
In general, an attribute set is built by a bitwise OR of the desired attribute components. The set of valid message queue attributes is provided in the following table:
RTEMS.FIFO - tasks wait by FIFO (default)
RTEMS.PRIORITY - tasks wait by priority
RTEMS.LOCAL - local message queue (default)
RTEMS.GLOBAL - global message queue
An attribute listed as a default is not required to
appear in the attribute list, although it is a good programming
practice to specify default attributes. If all defaults are
desired, the attribute RTEMS.DEFAULT_ATTRIBUTES
should be specified on this call.
This example demonstrates the attribute_set parameter
needed to create a local message queue with the task priority
waiting queue discipline. The attribute_set parameter to the
rtems.message_queue_create directive could be either
RTEMS.PRIORITY or
RTEMS.LOCAL or RTEMS.PRIORITY.
The attribute_set parameter can be set to RTEMS.PRIORITY
because RTEMS.LOCAL is the default for all created
message queues. If a similar message queue were to be known globally, then the
attribute_set parameter would be
RTEMS.GLOBAL or RTEMS.PRIORITY.
RTEMS Ada User's Guide
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