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.\" $FreeBSD: stable/10/lib/libc/sys/mq_setattr.2 222037 2011-05-17 21:03:34Z jilles $ 39.\" 40.Dd May 17, 2011 41.Dt MQ_SETATTR 2 42.Os 43.Sh NAME 44.Nm mq_setattr 45.Nd "set message queue attributes (REALTIME)" 46.Sh LIBRARY 47.Lb librt 48.Sh SYNOPSIS 49.In mqueue.h 50.Ft int 51.Fo mq_setattr 52.Fa "mqd_t mqdes" 53.Fa "const struct mq_attr *restrict mqstat" 54.Fa "struct mq_attr *restrict omqstat" 55.Fc 56.Sh DESCRIPTION 57The 58.Fn mq_setattr 59system call sets attributes associated with the open message queue description 60referenced by the message queue descriptor specified by 61.Fa mqdes . 62The message queue attributes corresponding to the following members defined 63in the 64.Vt mq_attr 65structure will be set to the specified values upon successful completion of 66.Fn mq_setattr : 67.Bl -tag -width ".Va mq_flags" 68.It Va mq_flags 69The value of this member is zero or 70.Dv O_NONBLOCK . 71.El 72.Pp 73The values of the 74.Va mq_maxmsg , mq_msgsize , 75and 76.Va mq_curmsgs 77members of the 78.Vt mq_attr 79structure are ignored by 80.Fn mq_setattr . 81.Sh RETURN VALUES 82Upon successful completion, the function returns a value of zero and the 83attributes of the message queue will have been changed as specified. 84.Pp 85Otherwise, the message queue attributes are unchanged, and the function 86returns a value of \-1 and sets the global variable 87.Va errno 88to indicate the error. 89.Sh ERRORS 90The 91.Fn mq_setattr 92system call 93will fail if: 94.Bl -tag -width Er 95.It Bq Er EBADF 96The 97.Fa mqdes 98argument is not a valid message queue descriptor. 99.El 100.Sh SEE ALSO 101.Xr mq_open 2 , 102.Xr mq_send 2 , 103.Xr mq_timedsend 2 104.Sh STANDARDS 105The 106.Fn mq_setattr 107system call conforms to 108.St -p1003.1-2004 . 109.Sh HISTORY 110Support for 111.Tn POSIX 112message queues first appeared in 113.Fx 7.0 . 114.Sh COPYRIGHT 115Portions of this text are reprinted and reproduced in electronic form 116from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- 117Portable Operating System Interface (POSIX), The Open Group Base 118Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of 119Electrical and Electronics Engineers, Inc and The Open Group. In the 120event of any discrepancy between this version and the original IEEE and 121The Open Group Standard, the original IEEE and The Open Group Standard is 122the referee document. The original Standard can be obtained online at 123http://www.opengroup.org/unix/online.html. 124