posix man page for mq_getattr

MQ_GETATTR(3P)						     POSIX Programmer's Manual						    MQ_GETATTR(3P)

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

NAME
       mq_getattr -- get message queue attributes (REALTIME)

SYNOPSIS
       #include <mqueue.h>

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

DESCRIPTION
       The mq_getattr() function shall obtain status information and attributes of the message queue and the open message queue description  asso-
       ciated 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.

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

ERRORS
       The mq_getattr() function may fail if:

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

       The following sections are informative.

EXAMPLES
       See mq_notify().

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

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

       The Base Definitions volume of POSIX.1-2008, <mqueue.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
       ogy  --	Portable  Operating  System  Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
       dard is the referee document. The original Standard can be obtained online at http://www.unix.org/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						       2013							    MQ_GETATTR(3P)