listen(7) [suse man page]

LISTEN(7)							   SQL Commands 							 LISTEN(7)

NAME

       LISTEN - listen for a notification

SYNOPSIS

       LISTEN name

DESCRIPTION

       LISTEN  registers  the current session as a listener on the notification condition name.  If the current session is already registered as a
       listener for this notification condition, nothing is done.

       Whenever the command NOTIFY name is invoked, either by this session or another one connected to the same database, all  the  sessions  cur-
       rently  listening  on that notification condition are notified, and each will in turn notify its connected client application. See the dis-
       cussion of NOTIFY for more information.

       A session can be unregistered for a given notify condition with the UNLISTEN command. A session's listen  registrations	are  automatically
       cleared when the session ends.

       The  method  a  client  application must use to detect notification events depends on which PostgreSQL application programming interface it
       uses. With the libpq library, the application issues LISTEN as an ordinary SQL command, and then must periodically call the function  PQno-
       tifies  to  find out whether any notification events have been received. Other interfaces such as libpgtcl provide higher-level methods for
       handling notify events; indeed, with libpgtcl the application programmer should not even issue LISTEN or UNLISTEN directly. See	the  docu-
       mentation for the interface you are using for more details.

       NOTIFY [notify(7)] contains a more extensive discussion of the use of LISTEN and NOTIFY.

PARAMETERS

       name   Name of a notify condition (any identifier).

EXAMPLES

       Configure and execute a listen/notify sequence from psql:

       LISTEN virtual;
       NOTIFY virtual;
       Asynchronous notification "virtual" received from server process with PID 8448.

COMPATIBILITY

       There is no LISTEN statement in the SQL standard.

SEE ALSO

       NOTIFY [notify(7)], UNLISTEN [unlisten(7)]

SQL - Language Statements					    2010-05-14								 LISTEN(7)

UPSD.CONF(5)							    NUT Manual							      UPSD.CONF(5)

NAME

       upsd.conf - Configuration for Network UPS Tools upsd

DESCRIPTION

       upsd uses this file to control access to the server and set some other miscellaneous configuration values. This file contains details on
       access controls, so keep it secure. Ideally, only the upsd process should be able to read it.

CONFIGURATION DIRECTIVES

       "MAXAGE seconds"
	   upsd usually allows a driver to stop responding for up to 15 seconds before declaring the data "stale". If your driver takes a very
	   long time to process updates but is otherwise operational, you can use MAXAGE to make upsd wait longer.

	   Most users should leave this at the default value.

       "STATEPATH path"
	   Tell upsd to look for the driver state sockets in path rather than the default that was compiled into the program.

       "LISTEN interface port"
	   Bind a listening port to the interface specified by its Internet address. This may be useful on hosts with multiple interfaces. You
	   should not rely exclusively on this for security, as it can be subverted on many systems.

	   Listen on TCP port port instead of the default value which was compiled into the code. This overrides any value you may have set with
	   configure --with-port. If you don't change it with configure or this value, upsd will listen on port 3493 for this interface.

	   Multiple LISTEN addresses may be specified. The default is to bind to 127.0.0.1 if no LISTEN addresses are specified (and ::1 if IPv6
	   support is compiled in).

	       LISTEN 127.0.0.1
	       LISTEN 192.168.50.1
	       LISTEN ::1
	       LISTEN 2001:0db8:1234:08d3:1319:8a2e:0370:7344

	   This parameter will only be read at startup. You'll need to restart (rather than reload) upsd to apply any changes made here.

       "MAXCONN connections"
	   This defaults to maximum number allowed on your system. Each UPS, each LISTEN address and each client count as one connection. If the
	   server runs out of connections, it will no longer accept new incoming client connections. Only set this if you know exactly what you're
	   doing.

       "CERTFILE certificate file"
	   When compiled with SSL support, you can enter the certificate file here. The certificates must be in PEM format and must be sorted
	   starting with the subject's certificate (server certificate), followed by intermediate CA certificates (if applicable_ and the highest
	   level (root) CA. It should end with the server key. See docs/security.txt or the Security chapter of NUT user manual for more
	   information on the SSL support in NUT.

SEE ALSO

       upsd(8), nutupsdrv(8), upsd.users(5)

INTERNET RESOURCES

       The NUT (Network UPS Tools) home page: http://www.networkupstools.org/

Network UPS Tools						    05/21/2012							      UPSD.CONF(5)