int
mq_setattr(
mqd_t mqdes
const struct mq_attr *restrict mqstat
struct mq_attr *restrict omqstat
)
)
function sets 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
structure will be set to the specified values upon successful completion of
mq_setattr():
O_NONBLOCK
and any implementation-defined flags.
The values of the
mq_maxmsg,
mq_msgsize,
and
mq_curmsgs
members of the
structure will be ignored by
mq_setattr().
If
omqstat
is
non-NULL
,
the
mq_setattr()
function will store, in the location referenced by
omqstat
the previous message queue attributes and the current queue status.
These values are the same as would be returned by a call to
mq_getattr(3)
at that point.
)
function returns zero and the attributes of the message queue will
have been changed as specified.
Otherwise, the message queue attributes are unchanged,
and the function returns a value of
-1 and sets the global variable
errno
to indicate the error.
)
function fails if:
EBADF
]
mqdes
argument is not a valid message queue descriptor.