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.TH MQ_SETATTR 3C "Feb 5, 2008"
.SH NAME
mq_setattr \- set/get message queue attributes
.SH SYNOPSIS
.LP
.nf
#include <mqueue.h>

\fBint\fR \fBmq_setattr\fR(\fBmqd_t\fR \fImqdes\fR, \fBconst struct mq_attr *\fR\fImqstat\fR,
     \fBstruct mq_attr *\fR\fIomqstat\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBmq_setattr()\fR function is used to set attributes associated with the
open message queue description referenced by the message queue descriptor
specified by \fImqdes\fR.
.sp
.LP
The message queue attributes corresponding to the following members defined in
the \fBmq_attr\fR structure are set to the specified values upon successful
completion of \fBmq_setattr()\fR:
.sp
.ne 2
.na
\fB\fBmq_flags\fR \fR
.ad
.RS 13n
The value of this member is either \fB0\fR or  \fBO_NONBLOCK.\fR
.RE

.sp
.LP
The values of \fBmq_maxmsg\fR, \fBmq_msgsize\fR, and \fBmq_curmsgs\fR are
ignored by \fBmq_setattr()\fR.
.sp
.LP
If \fIomqstat\fR is non-\fINULL\fR, \fBmq_setattr()\fR stores, in the location
referenced by \fIomqstat\fR, the previous message queue attributes and the
current queue status. These values are the same as would be returned by a call
to \fBmq_getattr()\fR at that point.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBmq_setattr()\fR returns \fB0\fR and the
attributes of the message queue will have been changed as specified. Otherwise,
the message queue attributes are unchanged, and the function returns
\fB\(mi1\fR and sets \fBerrno\fR to indicate the error.
.SH ERRORS
.sp
.LP
The \fBmq_setattr()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEBADF\fR \fR
.ad
.RS 11n
The \fImqdes\fR argument is not a valid message queue descriptor.
.RE

.sp
.ne 2
.na
\fB\fBENOSYS\fR \fR
.ad
.RS 11n
The \fBmq_setattr()\fR function is not supported by the system.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
_
MT-Level	MT-Safe
_
Standard	See \fBstandards\fR(7).
.TE

.SH SEE ALSO
.sp
.LP
.BR msgctl (2),
.BR msgget (2),
.BR msgrcv (2),
.BR msgsnd (2),
.BR mq_getattr (3C),
.BR mq_open (3C),
.BR mq_receive (3C),
.BR mq_send (3C),
.BR mqueue.h (3HEAD),
.BR attributes (7),
.BR standards (7)
.SH NOTES
.sp
.LP
Solaris 2.6 was the first release to support the Asynchronous Input and Output
option. Prior to this release, this function always returned \fB\(mi1\fR and
set \fBerrno\fR to \fBENOSYS\fR.