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MQ_SETATTR(3P)             POSIX Programmer's Manual            MQ_SETATTR(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_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>
COPYRIGHT
       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 .

IEEE/The Open Group                  2003                       MQ_SETATTR(3P)