MQ_SETATTR(3) Library Functions Manual MQ_SETATTR(3)
mq_setattr -- set message queue attributes (REALTIME)
POSIX Real-time Library (librt, -lrt)
mq_setattr(mqd_t mqdes, const struct mq_attr *restrict mqstat, struct
mq_attr *restrict omqstat);
The mq_setattr() 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 mq_attr structure will 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 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.
Upon successful completion, the mq_setattr() 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
The mq_setattr() function fails 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