MQ_GETATTR(3) Library Functions Manual MQ_GETATTR(3)
mq_getattr -- get message queue attributes (REALTIME)
POSIX Real-time Library (librt, -lrt)
mq_getattr(mqd_t mqdes, struct mq_attr *mqstat);
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 mq_attr structure referenced by the
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 mq_attr structure
referenced by the mqstat argument will be set to the current state of the
mq_curmsgs The number of messages currently on the queue.
The mq_getattr() function returns the value 0 if successful; otherwise
the value -1 is returned and the global variable errno is set to indicate
The mq_getattr() function may fail if:
[EBADF] The mqdes argument is not a valid message queue
This function conforms to the IEEE Std 1003.1-2001 (``POSIX.1'')
This function first appeared in NetBSD 5.0.
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
NetBSD 6.1.5 June 7, 2010 NetBSD 6.1.5