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_GETATTR(3P)						     POSIX Programmer's Manual						    MQ_GETATTR(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       mq_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  asso-
       ciated 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 referenced 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 ALSO

       mq_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 Technol-
       ogy -- 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(3P)