This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for  Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical  and  Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE  and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                    MQ_GETATTR(3POSIX)

       The  mq_getattr()  function  shall  obtain status information and attributes of the message queue and the
       open message queue description associated with the message queue descriptor.

       The mqdes argument specifies a message queue descriptor.

       The results shall be returned in the mq_attr structure referenced by the mqstat argument.

       Upon return, the following members  shall  have  the  values  associated  with  the  open  message  queue
       description  as  set  when the message queue was opened and as modified by subsequent mq_setattr() calls:
       mq_flags.

       The following attributes of the message queue shall  be  returned  as  set  at  message  queue  creation:
       mq_maxmsg, mq_msgsize.

       Upon  return,  the following members within the mq_attr structure referenced by the mqstat argument shall
       be set to the current state of the message queue:

       mq_curmsgs
                 The number of messages currently on the queue.

       The mq_getattr() function may fail if:

       EBADF  The mqdes argument is not a valid message queue descriptor.

       Thefollowingsectionsareinformative.

       See mq_notify().

       None.

       mq_getattr — get message queue attributes (REALTIME)

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

       None.

       Upon successful completion, the mq_getattr() function shall return zero. Otherwise,  the  function  shall
       return -1 and set errno to indicate the error.

mq_notify(), mq_open(), mq_send(), mq_setattr(), msgctl(), msgget(), msgrcv(), msgsnd()

       The Base Definitions volume of POSIX.1‐2017, <mqueue.h>

       #include <mqueue.h>

       int mq_getattr(mqd_t mqdes, struct mq_attr *mqstat);