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NAME
       mq_setattr - set message queue attributes (REALTIME)


SYNOPSIS
       #include <mqueue.h>

       int mq_setattr(mqd_t mqdes, const struct mq_attr *restrict mqstat,
              struct mq_attr *restrict omqstat);


DESCRIPTION
       The  mq_setattr()  function  shall  set  attributes  associated  with  the open message queue description
       referenced by the message queue descriptor specified by mqdes.

       The message queue attributes corresponding to the following members  defined  in  the  mq_attr  structure
       shall be set to the specified values upon successful completion of mq_setattr():

       mq_flags
              The  value  of  this  member  is  the  bitwise-logical  OR  of  zero or more of O_NONBLOCK and any
              implementation-defined flags.

       The values of the mq_maxmsg, mq_msgsize, and mq_curmsgs members of the mq_attr structure shall be ignored
       by mq_setattr().

       If omqstat is non-NULL, the mq_setattr() function shall store, in the location referenced by omqstat, the
       previous message queue attributes and the current queue status. These values shall be the same  as  would
       be returned by a call to mq_getattr() at that point.


RETURN VALUE
       Upon  successful  completion, the function shall return a value of zero and the attributes of the message
       queue shall have been changed as specified.

       Otherwise, the message queue attributes shall be unchanged, and the function shall return a value  of  -1
       and set errno to indicate the error.


ERRORS
       The mq_setattr() function shall fail if:

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

       The following sections are informative.


EXAMPLES
       None.


APPLICATION USAGE
       None.


RATIONALE
       None.


FUTURE DIRECTIONS
       None.


SEE ALSO
       mq_open() , mq_send() , mq_timedsend() , msgctl() , msgget() , msgrcv() , msgsnd() , the Base Definitions
       volume of IEEE Std 1003.1-2001, <mqueue.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 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 .