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 descriptor 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 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 .