MQ_SETATTR(P) POSIX Programmer's Manual MQ_SETATTR(P)NAMEmq_setattr - set message queue attributes (REALTIME)
SYNOPSIS
#include <mqueue.h>
int mq_setattr(mqd_t mqdes, const struct mq_attr *restrict mqstat,
struct mq_attr *restrict omqstat);
DESCRIPTION
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 flags.
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.
RETURN VALUE
Upon successful completion, the function shall return a value of zero
and the attributes of the message queue shall have been changed as
specified.
Otherwise, the message queue attributes shall be unchanged, and the
function shall return a value of -1 and set errno to indicate the
error.
ERRORS
The mq_setattr() function shall fail if:
EBADF The mqdes argument is not a valid message queue descriptor.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOmq_open() , mq_send() , mq_timedsend() , msgctl() , msgget() , msgrcv()
, msgsnd() , the Base Definitions volume of IEEE Std 1003.1-2001,
<mqueue.h>
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 .
IEEE/The Open Group 2003 MQ_SETATTR(P)
