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1.1       misho       1: .\" Copyright (c) 2001-2002 Packet Design, LLC.
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                     35: .\"
                     36: .\" Author: Archie Cobbs <archie@freebsd.org>
                     37: .\"
                     38: .\" $Id: mesg_port.3,v 1.7 2004/06/02 17:24:38 archie Exp $
                     39: .\"
                     40: .Dd April 22, 2002
                     41: .Dt MESG_PORT 3
                     42: .Os
                     43: .Sh NAME
                     44: .Nm mesg_port
                     45: .Nd generic message ports
                     46: .Sh LIBRARY
                     47: PDEL Library (libpdel, \-lpdel)
                     48: .Sh SYNOPSIS
                     49: .In pthread.h
                     50: .In pdel/util/mesg_port.h
                     51: .Ft "struct mesg_port *"
                     52: .Fn mesg_port_create "const char *mtype"
                     53: .Ft void
                     54: .Fn mesg_port_destroy "struct mesg_port **portp"
                     55: .Ft int
                     56: .Fn mesg_port_put "struct mesg_port *port" "void *data"
                     57: .Ft "void *"
                     58: .Fn mesg_port_get "struct mesg_port *port" "int timeout"
                     59: .Ft u_int
                     60: .Fn mesg_port_qlen "struct mesg_port *port"
                     61: .Sh DESCRIPTION
                     62: These functions implement a message port for inter-thread communication.
                     63: .Pp
                     64: .Fn mesg_port_create
                     65: creates a new messge port, using
                     66: .Xr typed_mem 3
                     67: type
                     68: .Fa mtype
                     69: for internal memory allocation.
                     70: .Pp
                     71: .Fn mesg_port_destroy
                     72: destroys the message port pointed to by
                     73: .Fa "*portp" .
                     74: There must be no messages in the message port, otherwise
                     75: .Fn mesg_port_destroy
                     76: aborts with an assertion failure.
                     77: Upon return,
                     78: .Fa "*portp"
                     79: will be set to
                     80: .Dv NULL .
                     81: If
                     82: .Fa "*portp"
                     83: is already
                     84: .Dv NULL
                     85: when
                     86: .Fn mesg_port_destroy
                     87: is invoked, nothing happens.
                     88: .Pp
                     89: .Fn mesg_port_put
                     90: writes the message represented by
                     91: .Fa data
                     92: to the message port pointed to by
                     93: .Fa port .
                     94: The
                     95: .Fa data
                     96: may not be
                     97: .Dv NULL .
                     98: .Pp
                     99: .Fn mesg_port_get
                    100: retrieves the next available message written to the message port pointed to by
                    101: .Fa port .
                    102: Messages are read in the same order as they are written.
                    103: If there are no messages,
                    104: .Fn mesg_port_get
                    105: waits for up to
                    106: .Fa timeout
                    107: milliseconds, or indefinitely if
                    108: .Fa timeout
                    109: is negative.
                    110: The thread calling
                    111: .Fn mesg_port_get
                    112: may be canceled without ill effect.
                    113: .Pp
                    114: .Fn mesg_port_qlen
                    115: returns the current number of messages queued on the message port pointed to by
                    116: .Fa port .
                    117: .Pp
                    118: .Fn mesg_port_put ,
                    119: .Fn mesg_port_get ,
                    120: and
                    121: .Fn mesg_port_qlen
                    122: may be called safely at the same time from different threads.
                    123: .Sh RETURN VALUES
                    124: .Fn mesg_port_create ,
                    125: .Fn mesg_port_put ,
                    126: and
                    127: .Fn mesg_port_get
                    128: return
                    129: .Dv NULL
                    130: or -1 to indicate an error,
                    131: with
                    132: .Va errno
                    133: set appropriately.
                    134: .Sh SEE ALSO
                    135: .Xr libpdel 3 ,
                    136: .Xr pevent 3 ,
                    137: .Xr pthread 3 ,
                    138: .Xr typed_mem 3
                    139: .Sh HISTORY
                    140: The PDEL library was developed at Packet Design, LLC.
                    141: .Dv "http://www.packetdesign.com/"
                    142: .Sh AUTHORS
                    143: .An Archie Cobbs Aq archie@freebsd.org