NAME

       mqueue.h - message queues (REALTIME)

SYNOPSIS

       #include <mqueue.h>

DESCRIPTION

       The  <mqueue.h>  header shall define the mqd_t type, which is used for message queue descriptors. This is
       not an array type.

       The <mqueue.h> header shall define the sigevent structure (as described in <signal.h> ) and  the  mq_attr
       structure,  which  is  used  in  getting  and  setting  the attributes of a message queue. Attributes are
       initially set when the message queue is created. An mq_attr structure shall have at least  the  following
       fields:

              long    mq_flags    Message queue flags.
              long    mq_maxmsg   Maximum number of messages.
              long    mq_msgsize  Maximum message size.
              long    mq_curmsgs  Number of messages currently queued.

       The following shall be declared as functions and may also be defined as macros. Function prototypes shall
       be provided.

              int      mq_close(mqd_t);
              int      mq_getattr(mqd_t, struct mq_attr *);
              int      mq_notify(mqd_t, const struct sigevent *);
              mqd_t    mq_open(const char *, int, ...);
              ssize_t  mq_receive(mqd_t, char *, size_t, unsigned *);
              int      mq_send(mqd_t, const char *, size_t, unsigned );
              int      mq_setattr(mqd_t, const struct mq_attr *restrict,
                           struct mq_attr *restrict);

              ssize_t  mq_timedreceive(mqd_t, char *restrict, size_t,
                           unsigned *restrict, const struct timespec *restrict);
              int      mq_timedsend(mqd_t, const char *, size_t, unsigned ,
                           const struct timespec *);

              int      mq_unlink(const char *);

       Inclusion of the <mqueue.h> header may make visible symbols defined in the headers <fcntl.h>, <signal.h>,
       <sys/types.h>, and <time.h>.

       The following sections are informative.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <fcntl.h> , <signal.h> , <sys/types.h> , <time.h> , the System Interfaces volume of IEEE Std 1003.1-2001,
       mq_close(),    mq_getattr(),    mq_notify(),    mq_open(),    mq_receive(),    mq_send(),   mq_setattr(),
       mq_timedreceive(), mq_timedsend(), mq_unlink()

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                                         <mqueue.h>(P)