freebsd-nq/lib/libc/sys/mq_setattr.2
Philip Paeps a975b4b6f2 Note, as required by our agreement with IEEE/The Open Group, that the message
queue manual pages excerpt the POSIX standard.

Spotted by:	Mindaugas Rasiukevicius <rmind -at- NetBSD.org>
Reviewed by:	imp
MFC after:	1 day
2008-02-21 19:16:57 +00:00

124 lines
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.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
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.\" 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 .
.\"
.\" $FreeBSD$
.\"
.Dd November 29, 2005
.Dt MQ_SETATTR 2
.Os
.Sh NAME
.Nm mq_setattr
.Nd "set message queue attributes (REALTIME)"
.Sh LIBRARY
.Lb librt
.Sh SYNOPSIS
.In mqueue.h
.Ft int
.Fo mq_setattr
.Fa "mqd_t mqdes"
.Fa "struct mq_attr *restrict mqstat"
.Fa "struct mq_attr *restrict omqstat"
.Fc
.Sh DESCRIPTION
The
.Fn mq_setattr
system call sets attributes associated with the open message queue description
referenced by the message queue descriptor specified by
.Fa mqdes .
The message queue attributes corresponding to the following members defined
in the
.Vt mq_attr
structure will be set to the specified values upon successful completion of
.Fn mq_setattr :
.Bl -tag -width ".Va mq_flags"
.It Va mq_flags
The value of this member is zero or
.Dv O_NONBLOCK .
.El
.Pp
The values of the
.Va mq_maxmsg , mq_msgsize ,
and
.Va mq_curmsgs
members of the
.Vt mq_attr
structure are ignored by
.Fn mq_setattr .
.Sh 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.
.Pp
Otherwise, the message queue attributes are unchanged, and the function
returns a value of \-1 and sets the global variable
.Va errno
to indicate the error.
.Sh ERRORS
The
.Fn mq_setattr
system call
will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa mqdes
argument is not a valid message queue descriptor.
.El
.Sh SEE ALSO
.Xr mq_open 2 ,
.Xr mq_send 2 ,
.Xr mq_timedsend 2
.Sh STANDARDS
The
.Fn mq_setattr
system call conforms to
.St -p1003.1-2004 .
.Sh HISTORY
Support for
.Tn POSIX
message queues first appeared in
.Fx 7.0 .
.Sh 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 .