Baoding-FenShuaJiang
/
Green_GoodERP18_FSJ_Standard


			
							<!DOCTYPE html>

<html lang="en" data-content_root="../">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<meta property="og:title" content="Runners" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://docs.python.org/3/library/asyncio-runner.html" />
<meta property="og:site_name" content="Python documentation" />
<meta property="og:description" content="Source code: Lib/asyncio/runners.py This section outlines high-level asyncio primitives to run asyncio code. They are built on top of an event loop with the aim to simplify async code usage for com..." />
<meta property="og:image" content="https://docs.python.org/3/_static/og-image.png" />
<meta property="og:image:alt" content="Python documentation" />
<meta name="description" content="Source code: Lib/asyncio/runners.py This section outlines high-level asyncio primitives to run asyncio code. They are built on top of an event loop with the aim to simplify async code usage for com..." />
<meta property="og:image:width" content="200" />
<meta property="og:image:height" content="200" />
<meta name="theme-color" content="#3776ab" />

    <title>Runners &#8212; Python 3.12.3 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
    
    <link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=80d5e7a1" />
    <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?v=bb723527" />
    <link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=b20cc3f5" />
    
    <script src="../_static/documentation_options.js?v=2c828074"></script>
    <script src="../_static/doctools.js?v=888ff710"></script>
    <script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
    
    <script src="../_static/sidebar.js"></script>
    
    <link rel="search" type="application/opensearchdescription+xml"
          title="Search within Python 3.12.3 documentation"
          href="../_static/opensearch.xml"/>
    <link rel="author" title="About these documents" href="../about.html" />
    <link rel="index" title="Index" href="../genindex.html" />
    <link rel="search" title="Search" href="../search.html" />
    <link rel="copyright" title="Copyright" href="../copyright.html" />
    <link rel="next" title="Coroutines and Tasks" href="asyncio-task.html" />
    <link rel="prev" title="asyncio — Asynchronous I/O" href="asyncio.html" />
    <link rel="canonical" href="https://docs.python.org/3/library/asyncio-runner.html" />
    
      
    <style>
      @media only screen {
        table.full-width-table {
            width: 100%;
        }
      }
    </style>
<link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
    <link rel="shortcut icon" type="image/png" href="../_static/py.svg" />
            <script type="text/javascript" src="../_static/copybutton.js"></script>
            <script type="text/javascript" src="../_static/menu.js"></script>
            <script type="text/javascript" src="../_static/search-focus.js"></script>
            <script type="text/javascript" src="../_static/themetoggle.js"></script> 

  </head>
<body>
<div class="mobile-nav">
    <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
           aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
    <nav class="nav-content" role="navigation">
        <label for="menuToggler" class="toggler__label">
            <span></span>
        </label>
        <span class="nav-items-wrapper">
            <a href="https://www.python.org/" class="nav-logo">
                <img src="../_static/py.svg" alt="Python logo"/>
            </a>
            <span class="version_switcher_placeholder"></span>
            <form role="search" class="search" action="../search.html" method="get">
                <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
                    <path fill-rule="nonzero" fill="currentColor" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"></path>
                </svg>
                <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" />
                <input type="submit" value="Go"/>
            </form>
        </span>
    </nav>
    <div class="menu-wrapper">
        <nav class="menu" role="navigation" aria-label="main navigation">
            <div class="language_switcher_placeholder"></div>
            
<label class="theme-selector-label">
    Theme
    <select class="theme-selector" oninput="activateTheme(this.value)">
        <option value="auto" selected>Auto</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
</label>
  <div>
    <h3><a href="../contents.html">Table of Contents</a></h3>
    <ul>
<li><a class="reference internal" href="#">Runners</a><ul>
<li><a class="reference internal" href="#running-an-asyncio-program">Running an asyncio Program</a></li>
<li><a class="reference internal" href="#runner-context-manager">Runner context manager</a></li>
<li><a class="reference internal" href="#handling-keyboard-interruption">Handling Keyboard Interruption</a></li>
</ul>
</li>
</ul>

  </div>
  <div>
    <h4>Previous topic</h4>
    <p class="topless"><a href="asyncio.html"
                          title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O</a></p>
  </div>
  <div>
    <h4>Next topic</h4>
    <p class="topless"><a href="asyncio-task.html"
                          title="next chapter">Coroutines and Tasks</a></p>
  </div>
  <div role="note" aria-label="source link">
    <h3>This Page</h3>
    <ul class="this-page-menu">
      <li><a href="../bugs.html">Report a Bug</a></li>
      <li>
        <a href="https://github.com/python/cpython/blob/main/Doc/library/asyncio-runner.rst"
            rel="nofollow">Show Source
        </a>
      </li>
    </ul>
  </div>
        </nav>
    </div>
</div>

  
    <div class="related" role="navigation" aria-label="related navigation">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             accesskey="I">index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="asyncio-task.html" title="Coroutines and Tasks"
             accesskey="N">next</a> |</li>
        <li class="right" >
          <a href="asyncio.html" title="asyncio — Asynchronous I/O"
             accesskey="P">previous</a> |</li>

          <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"/></li>
          <li><a href="https://www.python.org/">Python</a> &#187;</li>
          <li class="switchers">
            <div class="language_switcher_placeholder"></div>
            <div class="version_switcher_placeholder"></div>
          </li>
          <li>
              
          </li>
    <li id="cpython-language-and-version">
      <a href="../index.html">3.12.3 Documentation</a> &#187;
    </li>

          <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
          <li class="nav-item nav-item-2"><a href="ipc.html" >Networking and Interprocess Communication</a> &#187;</li>
          <li class="nav-item nav-item-3"><a href="asyncio.html" accesskey="U"><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O</a> &#187;</li>
        <li class="nav-item nav-item-this"><a href="">Runners</a></li>
                <li class="right">
                    

    <div class="inline-search" role="search">
        <form class="inline-search" action="../search.html" method="get">
          <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box" />
          <input type="submit" value="Go" />
        </form>
    </div>
                     |
                </li>
            <li class="right">
<label class="theme-selector-label">
    Theme
    <select class="theme-selector" oninput="activateTheme(this.value)">
        <option value="auto" selected>Auto</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
</label> |</li>
            
      </ul>
    </div>    

    <div class="document">
      <div class="documentwrapper">
        <div class="bodywrapper">
          <div class="body" role="main">
            
  <section id="runners">
<h1>Runners<a class="headerlink" href="#runners" title="Link to this heading">¶</a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.12/Lib/asyncio/runners.py">Lib/asyncio/runners.py</a></p>
<p>This section outlines high-level asyncio primitives to run asyncio code.</p>
<p>They are built on top of an <a class="reference internal" href="asyncio-eventloop.html#asyncio-event-loop"><span class="std std-ref">event loop</span></a> with the aim
to simplify async code usage for common wide-spread scenarios.</p>
<nav class="contents local" id="contents">
<ul class="simple">
<li><p><a class="reference internal" href="#running-an-asyncio-program" id="id1">Running an asyncio Program</a></p></li>
<li><p><a class="reference internal" href="#runner-context-manager" id="id2">Runner context manager</a></p></li>
<li><p><a class="reference internal" href="#handling-keyboard-interruption" id="id3">Handling Keyboard Interruption</a></p></li>
</ul>
</nav>
<section id="running-an-asyncio-program">
<h2><a class="toc-backref" href="#id1" role="doc-backlink">Running an asyncio Program</a><a class="headerlink" href="#running-an-asyncio-program" title="Link to this heading">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.run">
<span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">run</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">coro</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">debug</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">loop_factory</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.run" title="Link to this definition">¶</a></dt>
<dd><p>Execute the <a class="reference internal" href="../glossary.html#term-coroutine"><span class="xref std std-term">coroutine</span></a> <em>coro</em> and return the result.</p>
<p>This function runs the passed coroutine, taking care of
managing the asyncio event loop, <em>finalizing asynchronous
generators</em>, and closing the executor.</p>
<p>This function cannot be called when another asyncio event loop is
running in the same thread.</p>
<p>If <em>debug</em> is <code class="docutils literal notranslate"><span class="pre">True</span></code>, the event loop will be run in debug mode. <code class="docutils literal notranslate"><span class="pre">False</span></code> disables
debug mode explicitly. <code class="docutils literal notranslate"><span class="pre">None</span></code> is used to respect the global
<a class="reference internal" href="asyncio-dev.html#asyncio-debug-mode"><span class="std std-ref">Debug Mode</span></a> settings.</p>
<p>If <em>loop_factory</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, it is used to create a new event loop;
otherwise <a class="reference internal" href="asyncio-eventloop.html#asyncio.new_event_loop" title="asyncio.new_event_loop"><code class="xref py py-func docutils literal notranslate"><span class="pre">asyncio.new_event_loop()</span></code></a> is used. The loop is closed at the end.
This function should be used as a main entry point for asyncio programs,
and should ideally only be called once. It is recommended to use
<em>loop_factory</em> to configure the event loop instead of policies.</p>
<p>The executor is given a timeout duration of 5 minutes to shutdown.
If the executor hasn’t finished within that duration, a warning is
emitted and the executor is closed.</p>
<p>Example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">async</span> <span class="k">def</span> <span class="nf">main</span><span class="p">():</span>
    <span class="k">await</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
    <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;hello&#39;</span><span class="p">)</span>

<span class="n">asyncio</span><span class="o">.</span><span class="n">run</span><span class="p">(</span><span class="n">main</span><span class="p">())</span>
</pre></div>
</div>
<div class="versionadded">
<p><span class="versionmodified added">New in version 3.7.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.9: </span>Updated to use <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.shutdown_default_executor" title="asyncio.loop.shutdown_default_executor"><code class="xref py py-meth docutils literal notranslate"><span class="pre">loop.shutdown_default_executor()</span></code></a>.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.10: </span><em>debug</em> is <code class="docutils literal notranslate"><span class="pre">None</span></code> by default to respect the global debug mode settings.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.12: </span>Added <em>loop_factory</em> parameter.</p>
</div>
</dd></dl>

</section>
<section id="runner-context-manager">
<h2><a class="toc-backref" href="#id2" role="doc-backlink">Runner context manager</a><a class="headerlink" href="#runner-context-manager" title="Link to this heading">¶</a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="asyncio.Runner">
<em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">asyncio.</span></span><span class="sig-name descname"><span class="pre">Runner</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="o"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">debug</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">loop_factory</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.Runner" title="Link to this definition">¶</a></dt>
<dd><p>A context manager that simplifies <em>multiple</em> async function calls in the same
context.</p>
<p>Sometimes several top-level async functions should be called in the same <a class="reference internal" href="asyncio-eventloop.html#asyncio-event-loop"><span class="std std-ref">event
loop</span></a> and <a class="reference internal" href="contextvars.html#contextvars.Context" title="contextvars.Context"><code class="xref py py-class docutils literal notranslate"><span class="pre">contextvars.Context</span></code></a>.</p>
<p>If <em>debug</em> is <code class="docutils literal notranslate"><span class="pre">True</span></code>, the event loop will be run in debug mode. <code class="docutils literal notranslate"><span class="pre">False</span></code> disables
debug mode explicitly. <code class="docutils literal notranslate"><span class="pre">None</span></code> is used to respect the global
<a class="reference internal" href="asyncio-dev.html#asyncio-debug-mode"><span class="std std-ref">Debug Mode</span></a> settings.</p>
<p><em>loop_factory</em> could be used for overriding the loop creation.
It is the responsibility of the <em>loop_factory</em> to set the created loop as the
current one. By default <a class="reference internal" href="asyncio-eventloop.html#asyncio.new_event_loop" title="asyncio.new_event_loop"><code class="xref py py-func docutils literal notranslate"><span class="pre">asyncio.new_event_loop()</span></code></a> is used and set as
current event loop with <a class="reference internal" href="asyncio-eventloop.html#asyncio.set_event_loop" title="asyncio.set_event_loop"><code class="xref py py-func docutils literal notranslate"><span class="pre">asyncio.set_event_loop()</span></code></a> if <em>loop_factory</em> is <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
<p>Basically, <a class="reference internal" href="#asyncio.run" title="asyncio.run"><code class="xref py py-func docutils literal notranslate"><span class="pre">asyncio.run()</span></code></a> example can be rewritten with the runner usage:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">async</span> <span class="k">def</span> <span class="nf">main</span><span class="p">():</span>
    <span class="k">await</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
    <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;hello&#39;</span><span class="p">)</span>

<span class="k">with</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">Runner</span><span class="p">()</span> <span class="k">as</span> <span class="n">runner</span><span class="p">:</span>
    <span class="n">runner</span><span class="o">.</span><span class="n">run</span><span class="p">(</span><span class="n">main</span><span class="p">())</span>
</pre></div>
</div>
<div class="versionadded">
<p><span class="versionmodified added">New in version 3.11.</span></p>
</div>
<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Runner.run">
<span class="sig-name descname"><span class="pre">run</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">coro</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">context</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.Runner.run" title="Link to this definition">¶</a></dt>
<dd><p>Run a <a class="reference internal" href="../glossary.html#term-coroutine"><span class="xref std std-term">coroutine</span></a> <em>coro</em> in the embedded loop.</p>
<p>Return the coroutine’s result or raise its exception.</p>
<p>An optional keyword-only <em>context</em> argument allows specifying a
custom <a class="reference internal" href="contextvars.html#contextvars.Context" title="contextvars.Context"><code class="xref py py-class docutils literal notranslate"><span class="pre">contextvars.Context</span></code></a> for the <em>coro</em> to run in.
The runner’s default context is used if <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
<p>This function cannot be called when another asyncio event loop is
running in the same thread.</p>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Runner.close">
<span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.Runner.close" title="Link to this definition">¶</a></dt>
<dd><p>Close the runner.</p>
<p>Finalize asynchronous generators, shutdown default executor, close the event loop
and release embedded <a class="reference internal" href="contextvars.html#contextvars.Context" title="contextvars.Context"><code class="xref py py-class docutils literal notranslate"><span class="pre">contextvars.Context</span></code></a>.</p>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Runner.get_loop">
<span class="sig-name descname"><span class="pre">get_loop</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#asyncio.Runner.get_loop" title="Link to this definition">¶</a></dt>
<dd><p>Return the event loop associated with the runner instance.</p>
</dd></dl>

<div class="admonition note">
<p class="admonition-title">Note</p>
<p><a class="reference internal" href="#asyncio.Runner" title="asyncio.Runner"><code class="xref py py-class docutils literal notranslate"><span class="pre">Runner</span></code></a> uses the lazy initialization strategy, its constructor doesn’t
initialize underlying low-level structures.</p>
<p>Embedded <em>loop</em> and <em>context</em> are created at the <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> body entering
or the first call of <a class="reference internal" href="#asyncio.run" title="asyncio.run"><code class="xref py py-meth docutils literal notranslate"><span class="pre">run()</span></code></a> or <a class="reference internal" href="#asyncio.Runner.get_loop" title="asyncio.Runner.get_loop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_loop()</span></code></a>.</p>
</div>
</dd></dl>

</section>
<section id="handling-keyboard-interruption">
<h2><a class="toc-backref" href="#id3" role="doc-backlink">Handling Keyboard Interruption</a><a class="headerlink" href="#handling-keyboard-interruption" title="Link to this heading">¶</a></h2>
<div class="versionadded">
<p><span class="versionmodified added">New in version 3.11.</span></p>
</div>
<p>When <a class="reference internal" href="signal.html#signal.SIGINT" title="signal.SIGINT"><code class="xref py py-const docutils literal notranslate"><span class="pre">signal.SIGINT</span></code></a> is raised by <kbd class="kbd compound docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Ctrl</kbd>-<kbd class="kbd docutils literal notranslate">C</kbd></kbd>, <a class="reference internal" href="exceptions.html#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyboardInterrupt</span></code></a>
exception is raised in the main thread by default. However this doesn’t work with
<a class="reference internal" href="asyncio.html#module-asyncio" title="asyncio: Asynchronous I/O."><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code></a> because it can interrupt asyncio internals and can hang the program from
exiting.</p>
<p>To mitigate this issue, <a class="reference internal" href="asyncio.html#module-asyncio" title="asyncio: Asynchronous I/O."><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code></a> handles <a class="reference internal" href="signal.html#signal.SIGINT" title="signal.SIGINT"><code class="xref py py-const docutils literal notranslate"><span class="pre">signal.SIGINT</span></code></a> as follows:</p>
<ol class="arabic simple">
<li><p><a class="reference internal" href="#asyncio.Runner.run" title="asyncio.Runner.run"><code class="xref py py-meth docutils literal notranslate"><span class="pre">asyncio.Runner.run()</span></code></a> installs a custom <a class="reference internal" href="signal.html#signal.SIGINT" title="signal.SIGINT"><code class="xref py py-const docutils literal notranslate"><span class="pre">signal.SIGINT</span></code></a> handler before
any user code is executed and removes it when exiting from the function.</p></li>
<li><p>The <a class="reference internal" href="#asyncio.Runner" title="asyncio.Runner"><code class="xref py py-class docutils literal notranslate"><span class="pre">Runner</span></code></a> creates the main task for the passed coroutine for its
execution.</p></li>
<li><p>When <a class="reference internal" href="signal.html#signal.SIGINT" title="signal.SIGINT"><code class="xref py py-const docutils literal notranslate"><span class="pre">signal.SIGINT</span></code></a> is raised by <kbd class="kbd compound docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Ctrl</kbd>-<kbd class="kbd docutils literal notranslate">C</kbd></kbd>, the custom signal handler
cancels the main task by calling <a class="reference internal" href="asyncio-task.html#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate"><span class="pre">asyncio.Task.cancel()</span></code></a> which raises
<a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">asyncio.CancelledError</span></code></a> inside the main task.  This causes the Python stack
to unwind, <code class="docutils literal notranslate"><span class="pre">try/except</span></code> and <code class="docutils literal notranslate"><span class="pre">try/finally</span></code> blocks can be used for resource
cleanup.  After the main task is cancelled, <a class="reference internal" href="#asyncio.Runner.run" title="asyncio.Runner.run"><code class="xref py py-meth docutils literal notranslate"><span class="pre">asyncio.Runner.run()</span></code></a> raises
<a class="reference internal" href="exceptions.html#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyboardInterrupt</span></code></a>.</p></li>
<li><p>A user could write a tight loop which cannot be interrupted by
<a class="reference internal" href="asyncio-task.html#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate"><span class="pre">asyncio.Task.cancel()</span></code></a>, in which case the second following <kbd class="kbd compound docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Ctrl</kbd>-<kbd class="kbd docutils literal notranslate">C</kbd></kbd>
immediately raises the <a class="reference internal" href="exceptions.html#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyboardInterrupt</span></code></a> without cancelling the main task.</p></li>
</ol>
</section>
</section>


            <div class="clearer"></div>
          </div>
        </div>
      </div>
      <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
        <div class="sphinxsidebarwrapper">
  <div>
    <h3><a href="../contents.html">Table of Contents</a></h3>
    <ul>
<li><a class="reference internal" href="#">Runners</a><ul>
<li><a class="reference internal" href="#running-an-asyncio-program">Running an asyncio Program</a></li>
<li><a class="reference internal" href="#runner-context-manager">Runner context manager</a></li>
<li><a class="reference internal" href="#handling-keyboard-interruption">Handling Keyboard Interruption</a></li>
</ul>
</li>
</ul>

  </div>
  <div>
    <h4>Previous topic</h4>
    <p class="topless"><a href="asyncio.html"
                          title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O</a></p>
  </div>
  <div>
    <h4>Next topic</h4>
    <p class="topless"><a href="asyncio-task.html"
                          title="next chapter">Coroutines and Tasks</a></p>
  </div>
  <div role="note" aria-label="source link">
    <h3>This Page</h3>
    <ul class="this-page-menu">
      <li><a href="../bugs.html">Report a Bug</a></li>
      <li>
        <a href="https://github.com/python/cpython/blob/main/Doc/library/asyncio-runner.rst"
            rel="nofollow">Show Source
        </a>
      </li>
    </ul>
  </div>
        </div>
<div id="sidebarbutton" title="Collapse sidebar">
<span>«</span>
</div>

      </div>
      <div class="clearer"></div>
    </div>  
    <div class="related" role="navigation" aria-label="related navigation">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             >index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="asyncio-task.html" title="Coroutines and Tasks"
             >next</a> |</li>
        <li class="right" >
          <a href="asyncio.html" title="asyncio — Asynchronous I/O"
             >previous</a> |</li>

          <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"/></li>
          <li><a href="https://www.python.org/">Python</a> &#187;</li>
          <li class="switchers">
            <div class="language_switcher_placeholder"></div>
            <div class="version_switcher_placeholder"></div>
          </li>
          <li>
              
          </li>
    <li id="cpython-language-and-version">
      <a href="../index.html">3.12.3 Documentation</a> &#187;
    </li>

          <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
          <li class="nav-item nav-item-2"><a href="ipc.html" >Networking and Interprocess Communication</a> &#187;</li>
          <li class="nav-item nav-item-3"><a href="asyncio.html" ><code class="xref py py-mod docutils literal notranslate"><span class="pre">asyncio</span></code> — Asynchronous I/O</a> &#187;</li>
        <li class="nav-item nav-item-this"><a href="">Runners</a></li>
                <li class="right">
                    

    <div class="inline-search" role="search">
        <form class="inline-search" action="../search.html" method="get">
          <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box" />
          <input type="submit" value="Go" />
        </form>
    </div>
                     |
                </li>
            <li class="right">
<label class="theme-selector-label">
    Theme
    <select class="theme-selector" oninput="activateTheme(this.value)">
        <option value="auto" selected>Auto</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
</label> |</li>
            
      </ul>
    </div>  
    <div class="footer">
    &copy; 
      <a href="../copyright.html">
    
    Copyright
    
      </a>
     2001-2024, Python Software Foundation.
    <br />
    This page is licensed under the Python Software Foundation License Version 2.
    <br />
    Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
    <br />
    
      See <a href="/license.html">History and License</a> for more information.<br />
    
    
    <br />

    The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>
<br />
    <br />
      Last updated on Apr 09, 2024 (13:47 UTC).
    
      <a href="/bugs.html">Found a bug</a>?
    
    <br />

    Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 7.2.6.
    </div>

  </body>
</html>