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MESG_PORT(3)		    Library Functions Manual		  MESG_PORT(3)

NAME
       mesg_port -- generic message ports

LIBRARY
       PDEL Library (libpdel, -lpdel)

SYNOPSIS
       #include	<pthread.h>
       #include	<pdel/util/mesg_port.h>

       struct mesg_port	*
       mesg_port_create(const char *mtype);

       void
       mesg_port_destroy(struct	mesg_port **portp);

       int
       mesg_port_put(struct mesg_port *port, void *data);

       void *
       mesg_port_get(struct mesg_port *port, int timeout);

       u_int
       mesg_port_qlen(struct mesg_port *port);

DESCRIPTION
       These  functions	 implement  a message port for inter-thread communica-
       tion.

       mesg_port_create() creates a new	messge port, using  typed_mem(3)  type
       mtype for internal memory allocation.

       mesg_port_destroy()  destroys  the  message  port pointed to by *portp.
       There  must  be	no   messages	in   the   message   port,   otherwise
       mesg_port_destroy()  aborts  with  an  assertion	failure.  Upon return,
       *portp  will  be	 set  to  NULL.	  If  *portp  is  already  NULL	  when
       mesg_port_destroy() is invoked, nothing happens.

       mesg_port_put()	writes	the message represented	by data	to the message
       port pointed to by port.	 The data may not be NULL.

       mesg_port_get() retrieves the next available  message  written  to  the
       message	port  pointed to by port.  Messages are	read in	the same order
       as they are written.  If	there are no messages,	mesg_port_get()	 waits
       for up to timeout milliseconds, or indefinitely if timeout is negative.
       The thread calling mesg_port_get() may be canceled without ill effect.

       mesg_port_qlen()	 returns  the current number of	messages queued	on the
       message port pointed to by port.

       mesg_port_put(),	mesg_port_get(), and mesg_port_qlen()  may  be	called
       safely at the same time from different threads.

RETURN VALUES
       mesg_port_create(), mesg_port_put(), and	mesg_port_get()	return NULL or
       -1 to indicate an error,	with errno set appropriately.

SEE ALSO
       libpdel(3), pevent(3), pthread(3), typed_mem(3)

HISTORY
       The    PDEL    library	was   developed	  at   Packet	Design,	  LLC.
       http://www.packetdesign.com/

AUTHORS
       Archie Cobbs <archie@freebsd.org>

FreeBSD	ports 15.0		April 22, 2002			  MESG_PORT(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=mesg_port_qlen&sektion=3&manpath=FreeBSD+Ports+15.0>

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