<?xml version="1.0" encoding="latin1" ?> <!DOCTYPE erlref SYSTEM "erlref.dtd"> <erlref> <header> <copyright> <year>1996</year> <year>2007</year> <holder>Ericsson AB, All Rights Reserved</holder> </copyright> <legalnotice> The contents of this file are subject to the Erlang Public License, Version 1.1, (the "License"); you may not use this file except in compliance with the License. You should have received a copy of the Erlang Public License along with this software. If not, it can be retrieved online at http://www.erlang.org/. Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the specific language governing rights and limitations under the License. The Initial Developer of the Original Code is Ericsson AB. </legalnotice> <title>pg</title> <prepared></prepared> <docno></docno> <date></date> <rev></rev> </header> <module>pg</module> <modulesummary>Distributed, Named Process Groups</modulesummary> <description> <p>This (experimental) module implements process groups. A process group is a group of processes that can be accessed by a common name. For example, a group named <c>foobar</c> can include a set of processes as members of this group and they can be located on different nodes.</p> <p>When messages are sent to the named group, all members of the group receive the message. The messages are serialized. If the process <c>P1</c> sends the message <c>M1</c> to the group, and process <c>P2</c> simultaneously sends message <c>M2</c>, then all members of the group receive the two messages in the same order. If members of a group terminate, they are automatically removed from the group.</p> <p>This module is not complete. The module is inspired by the ISIS system and the causal order protocol of the ISIS system should also be implemented. At the moment, all messages are serialized by sending them through a group master process.</p> </description> <funcs> <func> <name>create(PgName) -> ok | {error, Reason}</name> <fsummary>Create an empty group</fsummary> <type> <v>PgName = term()</v> <v>Reason = already_created | term()</v> </type> <desc> <p>Creates an empty group named <c>PgName</c> on the current node.</p> </desc> </func> <func> <name>create(PgName, Node) -> ok | {error, Reason}</name> <fsummary>Create an empty group on another node</fsummary> <type> <v>PgName = term()</v> <v>Node = node()</v> <v>Reason = already_created | term()</v> </type> <desc> <p>Creates an empty group named <c>PgName</c> on the node <c>Node</c>.</p> </desc> </func> <func> <name>join(PgName, Pid) -> Members</name> <fsummary>Join a pid to a process group</fsummary> <type> <v>PgName = term()</v> <v>Pid = pid()</v> <v>Members = [pid()]</v> </type> <desc> <p>Joins the pid <c>Pid</c> to the process group <c>PgName</c>. Returns a list of all old members of the group.</p> </desc> </func> <func> <name>send(PgName, Msg) -> void()</name> <fsummary>Send a message to all members of a process group</fsummary> <type> <v>PgName = Msg = term()</v> </type> <desc> <p>Sends the tuple <c>{pg_message, From, PgName, Msg}</c> to all members of the process group <c>PgName</c>.</p> <p>Failure: <c>{badarg, {PgName, Msg}}</c> if <c>PgName</c> is not a process group (a globally registered name).</p> </desc> </func> <func> <name>esend(PgName, Msg) -> void()</name> <fsummary>Send a message to all members of a process group, except ourselves</fsummary> <type> <v>PgName = Msg = term()</v> </type> <desc> <p>Sends the tuple <c>{pg_message, From, PgName, Msg}</c> to all members of the process group <c>PgName</c>, except ourselves.</p> <p>Failure: <c>{badarg, {PgName, Msg}}</c> if <c>PgName</c> is not a process group (a globally registered name).</p> </desc> </func> <func> <name>members(PgName) -> Members</name> <fsummary>Return a list of all members of a process group</fsummary> <type> <v>PgName = term()</v> <v>Members = [pid()]</v> </type> <desc> <p>Returns a list of all members of the process group <c>PgName</c>.</p> </desc> </func> </funcs> </erlref>