70 lines
4.1 KiB
HTML
70 lines
4.1 KiB
HTML
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
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<title>Asynchronous Agents</title>
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<link rel="stylesheet" href="../../../boostbook.css" type="text/css">
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<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
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<link rel="home" href="../../../index.html" title="Asio">
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<link rel="up" href="../model.html" title="Asynchronous Model">
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<link rel="prev" href="async_ops.html" title="Asynchronous Operations">
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<link rel="next" href="associators.html" title="Associated Characteristics and Associators">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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</head>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
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<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../../asio.png"></td></tr></table>
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<hr>
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<div class="spirit-nav">
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<a accesskey="p" href="async_ops.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u" href="../model.html"><img src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png" alt="Home"></a><a accesskey="n" href="associators.html"><img src="../../../next.png" alt="Next"></a>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="asio.overview.model.async_agents"></a><a class="link" href="async_agents.html" title="Asynchronous Agents">Asynchronous Agents</a>
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</h4></div></div></div>
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<p>
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<span class="inlinemediaobject"><img src="../../../async_agent_model.png" width="931"></span>
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</p>
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<p>
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An <span class="emphasis"><em>asynchronous agent</em></span> is a sequential composition
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of asynchronous operations. Every asynchronous operation is considered
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to run as a part of an asynchronous agent, even if that agent contains
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only that single operation. An asynchronous agent is an entity that may
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perform work concurrently with other agents. Asynchronous agents are to
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asynchronous operations as threads are to synchronous operations.
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</p>
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<p>
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However, an asynchronous agent is a purely notional construct that allows
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us to reason about the context for, and composition of, asynchronous operations
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in a program. The name “asynchronous agent” does not appear in the
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library, nor is it important which concrete mechanism<sup>[<a name="asio.overview.model.async_agents.f0" href="#ftn.asio.overview.model.async_agents.f0" class="footnote">1</a>]</sup> is used to compose the asynchronous operations in an agent.
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</p>
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<p>
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We can visualise an asynchronous agent as follows:
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</p>
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<p>
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<span class="inlinemediaobject"><img src="../../../async_agent_chain.png" width="738"></span>
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</p>
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<p>
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Asynchronous agents alternately wait for an asynchronous operation to complete,
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and then run a completion handler for that operation. Within the context
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of an agent, these completion handlers represent indivisible units of schedulable
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work.
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</p>
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<div class="footnotes">
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<br><hr width="100" align="left">
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<div class="footnote"><p><sup>[<a name="ftn.asio.overview.model.async_agents.f0" href="#asio.overview.model.async_agents.f0" class="para">1</a>] </sup>
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Such as chains of lambdas, coroutines, fibers, state machines, etc.
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</p></div>
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</div>
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</div>
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<div class="copyright-footer">Copyright © 2003-2023 Christopher M. Kohlhoff<p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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</p>
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</div>
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<hr>
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<div class="spirit-nav">
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<a accesskey="p" href="async_ops.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u" href="../model.html"><img src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png" alt="Home"></a><a accesskey="n" href="associators.html"><img src="../../../next.png" alt="Next"></a>
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</div>
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</body>
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</html>
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