This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The mq_setattr() function shall set attributes associated with the
open message queue description referenced by the message queue
descriptor specified by mqdes.
The message queue attributes corresponding to the following members
defined in the mq_attr structure shall 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
The values of the mq_maxmsg, mq_msgsize, and mq_curmsgs members of
the mq_attr structure shall be ignored by mq_setattr().
If omqstat is non-NULL, the mq_setattr() function shall store, in the
location referenced by omqstat, the previous message queue attributes
and the current queue status. These values shall be the same as
would be returned by a call to mq_getattr() at that point.
Upon successful completion, the function shall return a value of zero
and the attributes of the message queue shall have been changed as
Otherwise, the message queue attributes shall be unchanged, and the
function shall return a value of −1 and set errno to indicate the
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 MQ_SETATTR(3P)