The mq_setattr() function shall set attributes associated with the open
message queue description referenced by the message queue descriptor specified
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():
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
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.
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.
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