NAME
mq_getattr
- get message queue attributes (REALTIME)
LIBRARY
POSIX Real-time Library (librt, -lrt)
SYNOPSIS
int
mq_getattr(
mqd_t mqdes
, struct mq_attr *mqstat
)
DESCRIPTION
The
mq_getattr(
)
function will obtain status information and attributes of the
message queue and the open message queue description associated
with the message queue descriptor.
The
mqdes
argument specifies a message queue descriptor.
The results are returned in the
structure referenced by the
mqstat
argument.
Upon return, the following members have the values associated with
the open message queue description as set when the message queue was
opened and as modified by subsequent
mq_setattr(3)
calls:
mq_flags.
The following attributes of the message queue will be returned as set
at message queue creation:
mq_maxmsg,
mq_msgsize.
Upon return, the following members within the
structure referenced by the
mqstat
argument will be set to the current state of the message queue:
- mq_curmsgs
-
The number of messages currently on the queue.
RETURN VALUES
ERRORS
The
mq_getattr(
)
function may fail if:
- [
EBADF
] -
The mqdes argument is not a valid message queue descriptor.
SEE ALSO
mq_close(3),
mq_notify(3),
mq_open(3),
mq_receive(3),
mq_send(3),
mq_setattr(3),
mq_unlink(3)
STANDARDS
This function conforms to the
IEEE Std 1003.1-2001 (``POSIX.1'')
standard.
HISTORY
This function first appeared in
NetBSD5.0.
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 .