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_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(), 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 Technology  --  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 Standard 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 .