MQ_SETATTR(2)             FreeBSD System Calls Manual            MQ_SETATTR(2)

NAME
     mq_setattr - set message queue attributes (REALTIME)

LIBRARY
     POSIX Real-time Library (librt, -lrt)

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() system call sets 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 will be set to the
     specified values upon successful completion of mq_setattr():

     mq_flags      The value of this member is zero or O_NONBLOCK.

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

RETURN VALUES
     Upon successful completion, the function returns a value of zero and the
     attributes of the message queue will have been changed as specified.

     Otherwise, the message queue attributes are unchanged, and the function
     returns a value of -1 and sets the global variable errno to indicate the
     error.

ERRORS
     The mq_setattr() 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_timedsend(2)

STANDARDS
     The mq_setattr() 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.

FreeBSD 13.1-RELEASE-p6          May 17, 2011          FreeBSD 13.1-RELEASE-p6