MQ_GETATTR(P) POSIX Programmer's Manual MQ_GETATTR(P)NAMEmq_getattr - get message queue attributes (REALTIME)
SYNOPSIS
#include <mqueue.h>
int mq_getattr(mqd_t mqdes, struct mq_attr *mqstat);
DESCRIPTION
The mq_getattr() function shall 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 shall be returned in the mq_attr structure referenced by
the mqstat argument.
Upon return, the following members shall 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 shall be returned as set
at message queue creation: mq_maxmsg, mq_msgsize.
Upon return, the following members within the mq_attr structure refer‐
enced by the mqstat argument shall be set to the current state of the
message queue:
mq_curmsgs
The number of messages currently on the queue.
RETURN VALUE
Upon successful completion, the mq_getattr() function shall return
zero. Otherwise, the function shall return -1 and set errno to indicate
the error.
ERRORS
The mq_getattr() function shall fail if:
EBADF The mqdes argument is not a valid message queue descriptor.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOmq_open() , mq_send() , mq_setattr() , mq_timedsend() , msgctl() ,
msgget() , msgrcv() , msgsnd() , the Base Definitions volume of
IEEE Std 1003.1-2001, <mqueue.h>
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 .
IEEE/The Open Group 2003 MQ_GETATTR(P)
