NAME

       mq_getattr — get message queue attributes (REALTIME)

LIBRARY

       POSIX Real-time Library (librt, -lrt)

SYNOPSIS

       #include <mqueue.h>

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

DESCRIPTION

       The  mq_getattr() system call obtains 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 are returned in the mq_attr structure referenced by the mqstat argument.

       Upon return, the following  members  will  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  will  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 will be
       set to the current state of the message queue:

       mq_curmsgs  The number of messages currently on the queue.

RETURN VALUES

       Upon  successful  completion,  the value 0 is returned; otherwise the value -1 is returned and the global
       variable errno is set to indicate the error.

ERRORS

       The mq_getattr() system call will fail if:

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

SEE ALSO

       mq_open(2), mq_send(2), mq_setattr(2), mq_timedsend(2)

STANDARDS

       The mq_getattr() system call conforms to IEEE Std 1003.1-2004 (“POSIX.1”).

HISTORY

       Support for POSIX message queues first appeared in FreeBSD 7.0.

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2004 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications Issue 6, Copyright (C) 2001-2004 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.

Debian                                          February 21, 2014                                  MQ_GETATTR(2)