mq_getattr(2) [debian man page]

MQ_GETATTR(2)						      BSD System Calls Manual						     MQ_GETATTR(2)

NAME

     mq_getattr -- get message queue attributes (REALTIME)

LIBRARY

     POSIX Real-time Library (librt, -lrt)

SYNOPSIS

     #include <mqueue.h>

     int
     mq_getattr(mqd_t mqdes, struct mq_attr *mqstat);

DESCRIPTION

     The mq_getattr() system call obtains 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 mqstat argument.

     Upon return, the following members will 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() 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
     message queue:

     mq_flags  The number of messages currently on the queue.

RETURN VALUES

     Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS

     The mq_getattr() system call will fail if:

     [EBADF]		The mqdes argument is not a valid message queue descriptor.

SEE ALSO

     mq_open(2), mq_send(2), mq_setattr(2), mq_timedsend(2)

STANDARDS

     The mq_getattr() system call conforms to IEEE Std 1003.1-2004 (``POSIX.1'').

HISTORY

     Support for POSIX message queues first appeared in FreeBSD 7.0.

COPYRIGHT

     Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology
     -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Elec-
     trical 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.

BSD
								 November 29, 2005							       BSD

MQ_SETATTR(3)						   BSD Library Functions Manual 					     MQ_SETATTR(3)

NAME

     mq_setattr -- set message queue attributes (REALTIME)

LIBRARY

     POSIX Real-time Library (librt, -lrt)

SYNOPSIS

     #include <mqueue.h>

     int
     mq_setattr(mqd_t mqdes, const struct mq_attr *restrict mqstat, struct mq_attr *restrict omqstat);

DESCRIPTION

     The mq_setattr() function sets attributes associated with the open message queue description referenced by the message queue descriptor spec-
     ified 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.

RETURN VALUES

     Upon successful completion, the mq_setattr() function returns zero and the attributes of the message queue will have been changed as speci-
     fied.  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.

ERRORS

     The mq_setattr() function fails if:

     [EBADF]		The mqdes argument is not a valid message queue descriptor.

SEE ALSO

     mq(3), mq_getattr(3)

STANDARDS

     This function conforms to the IEEE Std 1003.1-2001 (``POSIX.1'') standard.

HISTORY

     This function first appeared in NetBSD 5.0.

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 Elec-
     trical 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 .

BSD
								   June 7, 2010 							       BSD