DragonFly On-Line Manual Pages

Search: Section:  

MQ_SETATTR(2)            DragonFly 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() function sets attributes associated with the open mes-
     sage queue description referenced by the message queue descriptor speci-
     fied 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 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 will be ignored by mq_setattr().

     If omqstat is non-NULL, the mq_setattr() function will store, in the
     location referenced by omqstat the previous message queue attributes and
     the current queue status.  These values are the same as would be returned
     by a call to mq_getattr(2) at that point.


RETURN VALUES

     Upon successful completion, the mq_setattr() function returns 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() function fails if:

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


SEE ALSO

     mq_close(2), mq_getattr(2), mq_notify(2), mq_open(2), mq_receive(2),
     mq_send(2), mq_unlink(2)


STANDARDS

     This function conforms to the IEEE Std 1003.1-2001 (``POSIX.1'') stan-
     dard.


HISTORY

     This function first appeared in DragonFly 2.5.


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 Spec-
     ifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electri-
     cal 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 ref-
     eree document.  The original Standard can be obtained online at
     http://www.opengroup.org/unix/online.html .

DragonFly 3.5                   August 19, 2009                  DragonFly 3.5

Search: Section: