1.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice(s), this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified other than the possible 10.\" addition of one or more copyright notices. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice(s), this list of conditions and the following disclaimer in 13.\" the documentation and/or other materials provided with the 14.\" distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 20.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 23.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 25.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 26.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27.\" 28.\" Portions of this text are reprinted and reproduced in electronic form 29.\" from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- 30.\" Portable Operating System Interface (POSIX), The Open Group Base 31.\" Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of 32.\" Electrical and Electronics Engineers, Inc and The Open Group. In the 33.\" event of any discrepancy between this version and the original IEEE and 34.\" The Open Group Standard, the original IEEE and The Open Group Standard is 35.\" the referee document. The original Standard can be obtained online at 36.\" http://www.opengroup.org/unix/online.html. 37.\" 38.Dd May 17, 2011 39.Dt MQ_SETATTR 2 40.Os 41.Sh NAME 42.Nm mq_setattr 43.Nd "set message queue attributes (REALTIME)" 44.Sh LIBRARY 45.Lb librt 46.Sh SYNOPSIS 47.In mqueue.h 48.Ft int 49.Fo mq_setattr 50.Fa "mqd_t mqdes" 51.Fa "const struct mq_attr *restrict mqstat" 52.Fa "struct mq_attr *restrict omqstat" 53.Fc 54.Sh DESCRIPTION 55The 56.Fn mq_setattr 57system call sets attributes associated with the open message queue description 58referenced by the message queue descriptor specified by 59.Fa mqdes . 60The message queue attributes corresponding to the following members defined 61in the 62.Vt mq_attr 63structure will be set to the specified values upon successful completion of 64.Fn mq_setattr : 65.Bl -tag -width ".Va mq_flags" 66.It Va mq_flags 67The value of this member is zero or 68.Dv O_NONBLOCK . 69.El 70.Pp 71The values of the 72.Va mq_maxmsg , mq_msgsize , 73and 74.Va mq_curmsgs 75members of the 76.Vt mq_attr 77structure are ignored by 78.Fn mq_setattr . 79.Sh RETURN VALUES 80Upon successful completion, the function returns a value of zero and the 81attributes of the message queue will have been changed as specified. 82.Pp 83Otherwise, the message queue attributes are unchanged, and the function 84returns a value of \-1 and sets the global variable 85.Va errno 86to indicate the error. 87.Sh ERRORS 88The 89.Fn mq_setattr 90system call 91will fail if: 92.Bl -tag -width Er 93.It Bq Er EBADF 94The 95.Fa mqdes 96argument is not a valid message queue descriptor. 97.El 98.Sh SEE ALSO 99.Xr mq_open 2 , 100.Xr mq_send 2 , 101.Xr mq_timedsend 2 102.Sh STANDARDS 103The 104.Fn mq_setattr 105system call conforms to 106.St -p1003.1-2004 . 107.Sh HISTORY 108Support for 109.Tn POSIX 110message queues first appeared in 111.Fx 7.0 . 112.Sh COPYRIGHT 113Portions of this text are reprinted and reproduced in electronic form 114from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- 115Portable Operating System Interface (POSIX), The Open Group Base 116Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of 117Electrical and Electronics Engineers, Inc and The Open Group. In the 118event of any discrepancy between this version and the original IEEE and 119The Open Group Standard, the original IEEE and The Open Group Standard is 120the referee document. The original Standard can be obtained online at 121http://www.opengroup.org/unix/online.html. 122