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<div class="section" id="exceptions">
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<span id="asyncio-exceptions"></span><h1>Exceptions<a class="headerlink" href="#exceptions" title="Permalink to this headline">¶</a></h1>
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<dl class="exception">
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<dt id="asyncio.TimeoutError">
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<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">TimeoutError</code><a class="headerlink" href="#asyncio.TimeoutError" title="Permalink to this definition">¶</a></dt>
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<dd><p>The operation has exceeded the given deadline.</p>
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<div class="admonition important">
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<p class="admonition-title">Important</p>
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<p>This exception is different from the builtin <a class="reference internal" href="exceptions.html#TimeoutError" title="TimeoutError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TimeoutError</span></code></a>
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exception.</p>
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</div>
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</dd></dl>
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<dl class="exception">
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<dt id="asyncio.CancelledError">
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<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">CancelledError</code><a class="headerlink" href="#asyncio.CancelledError" title="Permalink to this definition">¶</a></dt>
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<dd><p>The operation has been cancelled.</p>
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<p>This exception can be caught to perform custom operations
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when asyncio Tasks are cancelled. In almost all situations the
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exception must be re-raised.</p>
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<div class="admonition important">
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<p class="admonition-title">Important</p>
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<p>This exception is a subclass of <a class="reference internal" href="exceptions.html#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Exception</span></code></a>, so it can be
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accidentally suppressed by an overly broad <code class="docutils literal notranslate"><span class="pre">try..except</span></code> block:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">try</span><span class="p">:</span>
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<span class="k">await</span> <span class="n">operation</span>
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<span class="k">except</span> <span class="ne">Exception</span><span class="p">:</span>
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<span class="c1"># The cancellation is broken because the *except* block</span>
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<span class="c1"># suppresses the CancelledError exception.</span>
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<span class="n">log</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s1">'an error has occurred'</span><span class="p">)</span>
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</pre></div>
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</div>
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<p>Instead, the following pattern should be used:</p>
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<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">try</span><span class="p">:</span>
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<span class="k">await</span> <span class="n">operation</span>
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<span class="k">except</span> <span class="n">asyncio</span><span class="o">.</span><span class="n">CancelledError</span><span class="p">:</span>
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<span class="k">raise</span>
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<span class="k">except</span> <span class="ne">Exception</span><span class="p">:</span>
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<span class="n">log</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s1">'an error has occurred'</span><span class="p">)</span>
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</pre></div>
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</div>
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</div>
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</dd></dl>
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<dl class="exception">
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<dt id="asyncio.InvalidStateError">
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<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">InvalidStateError</code><a class="headerlink" href="#asyncio.InvalidStateError" title="Permalink to this definition">¶</a></dt>
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<dd><p>Invalid internal state of <a class="reference internal" href="asyncio-task.html#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate"><span class="pre">Task</span></code></a> or <a class="reference internal" href="asyncio-future.html#asyncio.Future" title="asyncio.Future"><code class="xref py py-class docutils literal notranslate"><span class="pre">Future</span></code></a>.</p>
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<p>Can be raised in situations like setting a result value for a
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<em>Future</em> object that already has a result value set.</p>
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</dd></dl>
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<dl class="exception">
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<dt id="asyncio.SendfileNotAvailableError">
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<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">SendfileNotAvailableError</code><a class="headerlink" href="#asyncio.SendfileNotAvailableError" title="Permalink to this definition">¶</a></dt>
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<dd><p>The “sendfile” syscall is not available for the given
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socket or file type.</p>
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<p>A subclass of <a class="reference internal" href="exceptions.html#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">RuntimeError</span></code></a>.</p>
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</dd></dl>
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<dl class="exception">
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<dt id="asyncio.IncompleteReadError">
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<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">IncompleteReadError</code><a class="headerlink" href="#asyncio.IncompleteReadError" title="Permalink to this definition">¶</a></dt>
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<dd><p>The requested read operation did not complete fully.</p>
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<p>Raised by the <a class="reference internal" href="asyncio-stream.html#asyncio-streams"><span class="std std-ref">asyncio stream APIs</span></a>.</p>
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<p>This exception is a subclass of <a class="reference internal" href="exceptions.html#EOFError" title="EOFError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">EOFError</span></code></a>.</p>
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<dl class="attribute">
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<dt id="asyncio.IncompleteReadError.expected">
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<code class="descname">expected</code><a class="headerlink" href="#asyncio.IncompleteReadError.expected" title="Permalink to this definition">¶</a></dt>
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<dd><p>The total number (<a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a>) of expected bytes.</p>
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</dd></dl>
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<dl class="attribute">
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<dt id="asyncio.IncompleteReadError.partial">
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<code class="descname">partial</code><a class="headerlink" href="#asyncio.IncompleteReadError.partial" title="Permalink to this definition">¶</a></dt>
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<dd><p>A string of <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> read before the end of stream was reached.</p>
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</dd></dl>
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</dd></dl>
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<dl class="exception">
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<dt id="asyncio.LimitOverrunError">
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<em class="property">exception </em><code class="descclassname">asyncio.</code><code class="descname">LimitOverrunError</code><a class="headerlink" href="#asyncio.LimitOverrunError" title="Permalink to this definition">¶</a></dt>
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<dd><p>Reached the buffer size limit while looking for a separator.</p>
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<p>Raised by the <a class="reference internal" href="asyncio-stream.html#asyncio-streams"><span class="std std-ref">asyncio stream APIs</span></a>.</p>
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<dl class="attribute">
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<dt id="asyncio.LimitOverrunError.consumed">
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<code class="descname">consumed</code><a class="headerlink" href="#asyncio.LimitOverrunError.consumed" title="Permalink to this definition">¶</a></dt>
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<dd><p>The total number of to be consumed bytes.</p>
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