The
mq_close()
system call removes the association between the message queue descriptor,
mqdes,
and its message queue.
The results of using this message queue descriptor
after successful return from this
mq_close(),
and until the return of this message queue descriptor from a subsequent
mq_open(),
are undefined.
If the process has successfully attached a notification request to the
message queue via this
mqdes,
this attachment will be removed, and the message queue is available for
another process to attach for notification.