Return to mesg_port.3 CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / libpdel / util

libpdel

.\" Copyright (c) 2001-2002 Packet Design, LLC.
.\" All rights reserved.
.\" 
.\" Subject to the following obligations and disclaimer of warranty,
.\" use and redistribution of this software, in source or object code
.\" forms, with or without modifications are expressly permitted by
.\" Packet Design; provided, however, that:
.\" 
.\"    (i)  Any and all reproductions of the source or object code
.\"         must include the copyright notice above and the following
.\"         disclaimer of warranties; and
.\"    (ii) No rights are granted, in any manner or form, to use
.\"         Packet Design trademarks, including the mark "PACKET DESIGN"
.\"         on advertising, endorsements, or otherwise except as such
.\"         appears in the above copyright notice or in the software.
.\" 
.\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
.\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
.\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
.\" OR NON-INFRINGEMENT.  PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
.\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
.\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
.\" RELIABILITY OR OTHERWISE.  IN NO EVENT SHALL PACKET DESIGN BE
.\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
.\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
.\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
.\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
.\" THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
.\" THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" Author: Archie Cobbs <archie@freebsd.org>
.\"
.\" $Id: mesg_port.3,v 1.1.1.1 2012/02/21 23:25:53 misho Exp $
.\"
.Dd April 22, 2002
.Dt MESG_PORT 3
.Os
.Sh NAME
.Nm mesg_port
.Nd generic message ports
.Sh LIBRARY
PDEL Library (libpdel, \-lpdel)
.Sh SYNOPSIS
.In pthread.h
.In pdel/util/mesg_port.h
.Ft "struct mesg_port *"
.Fn mesg_port_create "const char *mtype"
.Ft void
.Fn mesg_port_destroy "struct mesg_port **portp"
.Ft int
.Fn mesg_port_put "struct mesg_port *port" "void *data"
.Ft "void *"
.Fn mesg_port_get "struct mesg_port *port" "int timeout"
.Ft u_int
.Fn mesg_port_qlen "struct mesg_port *port"
.Sh DESCRIPTION
These functions implement a message port for inter-thread communication.
.Pp
.Fn mesg_port_create
creates a new messge port, using
.Xr typed_mem 3
type
.Fa mtype
for internal memory allocation.
.Pp
.Fn mesg_port_destroy
destroys the message port pointed to by
.Fa "*portp" .
There must be no messages in the message port, otherwise
.Fn mesg_port_destroy
aborts with an assertion failure.
Upon return,
.Fa "*portp"
will be set to
.Dv NULL .
If
.Fa "*portp"
is already
.Dv NULL
when
.Fn mesg_port_destroy
is invoked, nothing happens.
.Pp
.Fn mesg_port_put
writes the message represented by
.Fa data
to the message port pointed to by
.Fa port .
The
.Fa data
may not be
.Dv NULL .
.Pp
.Fn mesg_port_get
retrieves the next available message written to the message port pointed to by
.Fa port .
Messages are read in the same order as they are written.
If there are no messages,
.Fn mesg_port_get
waits for up to
.Fa timeout
milliseconds, or indefinitely if
.Fa timeout
is negative.
The thread calling
.Fn mesg_port_get
may be canceled without ill effect.
.Pp
.Fn mesg_port_qlen
returns the current number of messages queued on the message port pointed to by
.Fa port .
.Pp
.Fn mesg_port_put ,
.Fn mesg_port_get ,
and
.Fn mesg_port_qlen
may be called safely at the same time from different threads.
.Sh RETURN VALUES
.Fn mesg_port_create ,
.Fn mesg_port_put ,
and
.Fn mesg_port_get
return
.Dv NULL
or -1 to indicate an error,
with
.Va errno
set appropriately.
.Sh SEE ALSO
.Xr libpdel 3 ,
.Xr pevent 3 ,
.Xr pthread 3 ,
.Xr typed_mem 3
.Sh HISTORY
The PDEL library was developed at Packet Design, LLC.
.Dv "http://www.packetdesign.com/"
.Sh AUTHORS
.An Archie Cobbs Aq archie@freebsd.org