mq_getattr(3) [netbsd man page]

MQ_GETATTR(3)						   BSD Library Functions Manual 					     MQ_GETATTR(3)

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() function will obtain status information and attributes of the message queue and the open message queue description associ-
     ated 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 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(3) 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_curmsgs  The number of messages currently on the queue.

RETURN VALUES

     The mq_getattr() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indi-
     cate the error.

ERRORS

     The mq_getattr() function may fail if:

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

SEE ALSO

     mq(3), mq_setattr(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

MQ_SETATTR(P)						     POSIX Programmer's Manual						     MQ_SETATTR(P)

NAME

       mq_setattr - set message queue attributes (REALTIME)

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 shall set attributes associated with the open message queue description referenced by the message queue descrip-
       tor specified by mqdes.

       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():

       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 shall be ignored by mq_setattr().

       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.

RETURN VALUE

       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.

ERRORS

       The mq_setattr() 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_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_SETATTR(P)