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| author | jacomi | 1999-04-12 17:18:34 +0000 |
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| committer | jacomi | 1999-04-12 17:18:34 +0000 |
| commit | f6a815b6504e9c954b9d0af57a3de6ccb75b5321 (patch) | |
| tree | 0e317b7410bc41fb42448e3452057e33aaf3c7d9 /doc/ivy-c-1.html | |
| parent | 9d094feea77b5b43b22620050dfe37caf56d9dff (diff) | |
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diff --git a/doc/ivy-c-1.html b/doc/ivy-c-1.html new file mode 100644 index 0000000..69e9dee --- /dev/null +++ b/doc/ivy-c-1.html @@ -0,0 +1,114 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> +<HTML> +<HEAD> + <META NAME="GENERATOR" CONTENT="SGML-Tools 1.0.7"> + <TITLE>The Ivy C library guide: General information</TITLE> + <LINK HREF="ivy-c-2.html" REL=next> + + <LINK HREF="ivy-c.html#toc1" REL=contents> +</HEAD> +<BODY> +<A HREF="ivy-c-2.html">Next</A> +Previous +<A HREF="ivy-c.html#toc1">Contents</A> +<HR> +<H2><A NAME="s1">1. General information</A></H2> + +<H2><A NAME="ss1.1">1.1 What is Ivy?</A> +</H2> + +<P> +<P>Ivy is a software bus designed at CENA (France). A software bus is a system +that allows software applications to exchange information with the illusion of +broadcasting that information, selection being performed by the receiving +applications. Using a software bus is very similar to dealing with events in a +graphical toolkit: on one side, messages are emitted without caring about who +will handle them, and on the other side, one decide to handle the messages that +have a certain type or follow a certain pattern. Software buses are mainly aimed +at facilitating the rapid development of new agents, and at managing a dynamic +collection of agents on the bus: agents show up, emit messages and receive some, +then leave the bus without blocking the others. +<P> +<H3>Architecture and principles</H3> + +<P>As opposed to other software buses, Ivy does not depend on a centralised +server. Actually, Ivy is mostly a communication convention between processes, +implemented through a collection of libraries in several languages. +<P> +<P> +<P>From the programmer's point of view, Ivy is an information broadcasting +channel. The main functions are: +<P> +<UL> +<LI> connecting to a bus.<EM> Example: IvyInit (b, 2011)</EM></LI> +<LI> sending a message.<EM> Example: IvySend (b, "HELLO %s", world)</EM></LI> +<LI> bind a message pattern to a callback function.<EM> Example: IvyBind (b, "HELLO (.*)", cb)</EM></LI> +<LI> the main loop.<EM> Example : IvyLoop ()</EM></LI> +</UL> +<P>Ivy's +decentralised connection scheme probably incurs limitations in terms of how many +applications can be connected to an Ivy bus, but this simplifies management a +lot. Basically, an Ivy bus is just a set of applications that decide to +communicate together. The only conventions between these applications are: +<OL> +<LI> the use of the Ivy protocol (for obvious reasons)</LI> +<LI> a bus address, made of a broadcast port number (a bit like a citizen band +channel) and a set of networks addresses</LI> +</OL> + +When an application wants to connect to a bus, it sends a broadcast message on the +networks specified in the bus address, so that all applications present on those +networks and listening on the specified port number connect to it. It then +becomes part of the bus, and listens like the other ones. +<P>The messages are exchanged in text format, and bindings are based on regular +expressions with captures. If an application subscribes to +<CODE>HELLO (.*)</CODE> an if another application emits the message <CODE>HELLO WORLD</CODE>, a +callback will be called in the first application with <CODE>WORLD</CODE> as an argument. +<P> +<P> +<H3>Using Ivy</H3> + +<P>You can use Ivy through applications that have been provided to you. This is the +case for <CODE>ivyprobe</CODE>, an Ivy agent that allows you to examine the messages +exchanged on a given bus and to send messages on that bus. You can refer to the +web site <CODE>http:</CODE> for a list of available agents. However, what you will +usually want to do is to develop your own applications. In order to do that you +can use an Ivy connection kit, that is a library that implements Ivy. +<P> +<P> +<P>Libraries that implement Ivy are available in the following environments: +<UL> +<LI> in C on Unix and Windows platforms, with it own communication library</LI> +<LI> in C++ on Windows platforms</LI> +<LI> in C++ on Unix platforms, integrated with the Uch communication library</LI> +<LI> in C++ on Unix platforms, integrated with OpenInventor</LI> +<LI> in C++ on Macintosh</LI> +<LI> in Perl and in Perl/Tk</LI> +<LI> integrated with Object Caml on Unix platforms</LI> +<LI> in Scheme on Unix platforms</LI> +<LI> in Java</LI> +</UL> +<P> +<P>Connecting your application to an Ivy bus just consists in choosing the +appropriate library, add the appropriate message emission and reception calls to +your code, use the main loop provided in the library or make the necessary +integrations, and get your code running! +<P> +<H2><A NAME="ss1.2">1.2 The Ivy C library</A> +</H2> + +<P>The Ivy C library (aka Ivy-C or ivy-c) is a C library that allows you to connect +applications to an Ivy bus. You can use it to write applications in C or any +other language that supports C extensions. This guide documents how you can do +that. +<P>The Ivy C library is known to compile and work in WindowsNT and Linux +environments. It should be easy to use on most Posix environments. +<P>The Ivy C library was originally developed by François-Régis Colin at CENA. It +is maintained by the CENA-Toulouse team. +<P> +<HR> +<A HREF="ivy-c-2.html">Next</A> +Previous +<A HREF="ivy-c.html#toc1">Contents</A> +</BODY> +</HTML> |