mq_getattr(3p) — Linux manual page

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
       corresponding 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 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.

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(3p).

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       mq_notify(3p), mq_open(3p), mq_send(3p), mq_setattr(3p),
       msgctl(3p), msgget(3p), msgrcv(3p), msgsnd(3p)

       The Base Definitions volume of POSIX.1‐2017, mqueue.h(0p)

COPYRIGHT

       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(3P)

Pages that refer to this page: mqueue.h(0p), mq_open(3p), msgctl(3p), msgget(3p), msgrcv(3p), msgsnd(3p)

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