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<section id="module-xdrlib">
<span id="xdrlib-encode-and-decode-xdr-data"></span><h1><a class="reference internal" href="#module-xdrlib" title="xdrlib: Encoders and decoders for the External Data Representation (XDR)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">xdrlib</span></code></a> --- 编码与解码 XDR 数据<a class="headerlink" href="#module-xdrlib" title="永久链接至标题"></a></h1>
<p><strong>源代码:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.8/Lib/xdrlib.py">Lib/xdrlib.py</a></p>
<hr class="docutils" id="index-0" />
<p><a class="reference internal" href="#module-xdrlib" title="xdrlib: Encoders and decoders for the External Data Representation (XDR)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">xdrlib</span></code></a> 模块为外部数据表示标准提供支持，该标准的描述见 <span class="target" id="index-9"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1014.html"><strong>RFC 1014</strong></a>，由 Sun Microsystems, Inc. 在 1987 年 6 月撰写。 它支持该 RFC 中描述的大部分数据类型。</p>
<p><a class="reference internal" href="#module-xdrlib" title="xdrlib: Encoders and decoders for the External Data Representation (XDR)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">xdrlib</span></code></a> 模块定义了两个类，一个用于将变量打包为 XDR 表示形式，另一个用于从 XDR 表示形式解包。 此外还有两个异常类。</p>
<dl class="class">
<dt id="xdrlib.Packer">
<em class="property">class </em><code class="sig-prename descclassname">xdrlib.</code><code class="sig-name descname">Packer</code><a class="headerlink" href="#xdrlib.Packer" title="永久链接至目标"></a></dt>
<dd><p><a class="reference internal" href="#xdrlib.Packer" title="xdrlib.Packer"><code class="xref py py-class docutils literal notranslate"><span class="pre">Packer</span></code></a> 是用于将数据打包为 XDR 表示形式的类。 <a class="reference internal" href="#xdrlib.Packer" title="xdrlib.Packer"><code class="xref py py-class docutils literal notranslate"><span class="pre">Packer</span></code></a> 类的实例化不附带参数。</p>
</dd></dl>
<dl class="class">
<dt id="xdrlib.Unpacker">
<em class="property">class </em><code class="sig-prename descclassname">xdrlib.</code><code class="sig-name descname">Unpacker</code><span class="sig-paren">(</span><em class="sig-param">data</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker" title="永久链接至目标"></a></dt>
<dd><p><code class="docutils literal notranslate"><span class="pre">Unpacker</span></code> 是用于相应地从字符串缓冲区解包 XDR 数据值的类。 输入缓冲区将作为 <em>data</em> 给出。</p>
</dd></dl>
<div class="admonition seealso">
<p class="admonition-title">参见</p>
<dl class="simple">
<dt><span class="target" id="index-10"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1014.html"><strong>RFC 1014</strong></a> - XDR: 外部数据表示标准</dt><dd><p>这个 RFC 定义了最初编写此模块时 XDR 所用的数据编码格式。 显然它已被 <span class="target" id="index-11"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1832.html"><strong>RFC 1832</strong></a> 所淘汰。</p>
</dd>
<dt><span class="target" id="index-12"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc1832.html"><strong>RFC 1832</strong></a> - XDR: 外部数据表示标准</dt><dd><p>更新的 RFC，它提供了经修订的 XDR 定义。</p>
</dd>
</dl>
</div>
<section id="packer-objects">
<span id="xdr-packer-objects"></span><h2>Packer 对象<a class="headerlink" href="#packer-objects" title="永久链接至标题"></a></h2>
<p><a class="reference internal" href="#xdrlib.Packer" title="xdrlib.Packer"><code class="xref py py-class docutils literal notranslate"><span class="pre">Packer</span></code></a> 实例具有下列方法:</p>
<dl class="method">
<dt id="xdrlib.Packer.get_buffer">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">get_buffer</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.get_buffer" title="永久链接至目标"></a></dt>
<dd><p>将当前打包缓冲区以字符串的形式返回。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.reset">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">reset</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.reset" title="永久链接至目标"></a></dt>
<dd><p>将打包缓冲区重置为空字符串。</p>
</dd></dl>
<p>总体来说，你可以通过调用适当的 <code class="docutils literal notranslate"><span class="pre">pack_type()</span></code> 方法来打包任何最常见的 XDR 数据类型。 每个方法都是接受单个参数，即要打包的值。 受支持的简单数据类型打包方法如下: <code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_uint()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_int()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_enum()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_bool()</span></code>, <code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_uhyper()</span></code> 以及 <code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_hyper()</span></code>。</p>
<dl class="method">
<dt id="xdrlib.Packer.pack_float">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_float</code><span class="sig-paren">(</span><em class="sig-param">value</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_float" title="永久链接至目标"></a></dt>
<dd><p>打包单精度浮点数 <em>value</em>。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_double">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_double</code><span class="sig-paren">(</span><em class="sig-param">value</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_double" title="永久链接至目标"></a></dt>
<dd><p>打包双精度浮点数 <em>value</em>。</p>
</dd></dl>
<p>以下方法支持打包字符串、字节串以及不透明数据。</p>
<dl class="method">
<dt id="xdrlib.Packer.pack_fstring">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_fstring</code><span class="sig-paren">(</span><em class="sig-param">n</em>, <em class="sig-param">s</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_fstring" title="永久链接至目标"></a></dt>
<dd><p>打包固定长度字符串 <em>s</em>。 <em>n</em> 为字符串的长度，但它 <em>不会</em> 被打包进数据缓冲区。 如有必要字符串会以空字节串填充以保证 4 字节对齐。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_fopaque">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_fopaque</code><span class="sig-paren">(</span><em class="sig-param">n</em>, <em class="sig-param">data</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_fopaque" title="永久链接至目标"></a></dt>
<dd><p>打包固定长度不透明数据流，类似于 <a class="reference internal" href="#xdrlib.Packer.pack_fstring" title="xdrlib.Packer.pack_fstring"><code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_fstring()</span></code></a>。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_string">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_string</code><span class="sig-paren">(</span><em class="sig-param">s</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_string" title="永久链接至目标"></a></dt>
<dd><p>打包可变长度字符串 <em>s</em>。 先将字符串的长度打包为无符号整数，再用 <a class="reference internal" href="#xdrlib.Packer.pack_fstring" title="xdrlib.Packer.pack_fstring"><code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_fstring()</span></code></a> 来打包字符串数据。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_opaque">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_opaque</code><span class="sig-paren">(</span><em class="sig-param">data</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_opaque" title="永久链接至目标"></a></dt>
<dd><p>打包可变长度不透明数据流，类似于 <a class="reference internal" href="#xdrlib.Packer.pack_string" title="xdrlib.Packer.pack_string"><code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_string()</span></code></a>。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_bytes">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_bytes</code><span class="sig-paren">(</span><em class="sig-param">bytes</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_bytes" title="永久链接至目标"></a></dt>
<dd><p>打包可变长度字节流，类似于 <a class="reference internal" href="#xdrlib.Packer.pack_string" title="xdrlib.Packer.pack_string"><code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_string()</span></code></a>。</p>
</dd></dl>
<p>下列方法支持打包数组和列表:</p>
<dl class="method">
<dt id="xdrlib.Packer.pack_list">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_list</code><span class="sig-paren">(</span><em class="sig-param">list</em>, <em class="sig-param">pack_item</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_list" title="永久链接至目标"></a></dt>
<dd><p>打包由同质条目构成的 <em>list</em>。 此方法适用于不确定长度的列表；即其长度无法在遍历整个列表之前获知。 对于列表中的每个条目，先打包一个无符号整数 <code class="docutils literal notranslate"><span class="pre">1</span></code>，再添加列表中数据的值。 <em>pack_item</em> 是在打包单个条目时要调用的函数。 在列表的末尾，会再打包一个无符号整数 <code class="docutils literal notranslate"><span class="pre">0</span></code>。</p>
<p>例如，要打包一个整数列表，代码看起来会是这样:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">xdrlib</span>
<span class="n">p</span> <span class="o">=</span> <span class="n">xdrlib</span><span class="o">.</span><span class="n">Packer</span><span class="p">()</span>
<span class="n">p</span><span class="o">.</span><span class="n">pack_list</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="n">p</span><span class="o">.</span><span class="n">pack_int</span><span class="p">)</span>
</pre></div>
</div>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_farray">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_farray</code><span class="sig-paren">(</span><em class="sig-param">n</em>, <em class="sig-param">array</em>, <em class="sig-param">pack_item</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_farray" title="永久链接至目标"></a></dt>
<dd><p>打包由同质条目构成的固定长度列表 (<em>array</em>)。 <em>n</em> 为列表长度；它 <em>不会</em> 被打包到缓冲区，但是如果 <code class="docutils literal notranslate"><span class="pre">len(array)</span></code> 不等于 <em>n</em> 则会引发 <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a>。 如上所述，<em>pack_item</em> 是在打包每个元素时要使用的函数。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Packer.pack_array">
<code class="sig-prename descclassname">Packer.</code><code class="sig-name descname">pack_array</code><span class="sig-paren">(</span><em class="sig-param">list</em>, <em class="sig-param">pack_item</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Packer.pack_array" title="永久链接至目标"></a></dt>
<dd><p>打包由同质条目构成的可变长度 <em>list</em>。 先将列表的长度打包为无符号整数，再像上面的 <a class="reference internal" href="#xdrlib.Packer.pack_farray" title="xdrlib.Packer.pack_farray"><code class="xref py py-meth docutils literal notranslate"><span class="pre">pack_farray()</span></code></a> 一样打包每个元素。</p>
</dd></dl>
</section>
<section id="unpacker-objects">
<span id="xdr-unpacker-objects"></span><h2>Unpacker 对象<a class="headerlink" href="#unpacker-objects" title="永久链接至标题"></a></h2>
<p><a class="reference internal" href="#xdrlib.Unpacker" title="xdrlib.Unpacker"><code class="xref py py-class docutils literal notranslate"><span class="pre">Unpacker</span></code></a> 类提供以下方法:</p>
<dl class="method">
<dt id="xdrlib.Unpacker.reset">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">reset</code><span class="sig-paren">(</span><em class="sig-param">data</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.reset" title="永久链接至目标"></a></dt>
<dd><p>使用给定的 <em>data</em> 重置字符串缓冲区。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.get_position">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">get_position</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.get_position" title="永久链接至目标"></a></dt>
<dd><p>返回数据缓冲区中的当前解包位置。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.set_position">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">set_position</code><span class="sig-paren">(</span><em class="sig-param">position</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.set_position" title="永久链接至目标"></a></dt>
<dd><p>将数据缓冲区的解包位置设为 <em>position</em>。 你应当小心使用 <a class="reference internal" href="#xdrlib.Unpacker.get_position" title="xdrlib.Unpacker.get_position"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_position()</span></code></a> 和 <a class="reference internal" href="#xdrlib.Unpacker.set_position" title="xdrlib.Unpacker.set_position"><code class="xref py py-meth docutils literal notranslate"><span class="pre">set_position()</span></code></a>。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.get_buffer">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">get_buffer</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.get_buffer" title="永久链接至目标"></a></dt>
<dd><p>将当前解包数据缓冲区以字符串的形式返回。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.done">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">done</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.done" title="永久链接至目标"></a></dt>
<dd><p>表明解包完成。 如果数据没有全部完成解包则会引发 <a class="reference internal" href="#xdrlib.Error" title="xdrlib.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Error</span></code></a> 异常。</p>
</dd></dl>
<p>此外，每种可通过 <a class="reference internal" href="#xdrlib.Packer" title="xdrlib.Packer"><code class="xref py py-class docutils literal notranslate"><span class="pre">Packer</span></code></a> 打包的数据类型都可通过 <a class="reference internal" href="#xdrlib.Unpacker" title="xdrlib.Unpacker"><code class="xref py py-class docutils literal notranslate"><span class="pre">Unpacker</span></code></a> 来解包。 解包方法的形式为 <code class="docutils literal notranslate"><span class="pre">unpack_type()</span></code>，并且不接受任何参数。 该方法将返回解包后的对象。</p>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_float">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_float</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_float" title="永久链接至目标"></a></dt>
<dd><p>解包单精度浮点数。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_double">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_double</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_double" title="永久链接至目标"></a></dt>
<dd><p>解包双精度浮点数，类似于 <a class="reference internal" href="#xdrlib.Unpacker.unpack_float" title="xdrlib.Unpacker.unpack_float"><code class="xref py py-meth docutils literal notranslate"><span class="pre">unpack_float()</span></code></a>。</p>
</dd></dl>
<p>此外，以下方法可用来解包字符串、字节串以及不透明数据:</p>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_fstring">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_fstring</code><span class="sig-paren">(</span><em class="sig-param">n</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_fstring" title="永久链接至目标"></a></dt>
<dd><p>解包并返回固定长度字符串。 <em>n</em> 为期望的字符数量。 会预设以空字节串填充以保证 4 字节对齐。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_fopaque">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_fopaque</code><span class="sig-paren">(</span><em class="sig-param">n</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_fopaque" title="永久链接至目标"></a></dt>
<dd><p>解包并返回固定长度数据流，类似于 <a class="reference internal" href="#xdrlib.Unpacker.unpack_fstring" title="xdrlib.Unpacker.unpack_fstring"><code class="xref py py-meth docutils literal notranslate"><span class="pre">unpack_fstring()</span></code></a>。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_string">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_string</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_string" title="永久链接至目标"></a></dt>
<dd><p>解包并返回可变长度字符串。 先将字符串的长度解包为无符号整数，再用 <a class="reference internal" href="#xdrlib.Unpacker.unpack_fstring" title="xdrlib.Unpacker.unpack_fstring"><code class="xref py py-meth docutils literal notranslate"><span class="pre">unpack_fstring()</span></code></a> 来解包字符串数据。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_opaque">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_opaque</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_opaque" title="永久链接至目标"></a></dt>
<dd><p>解包并返回可变长度不透明数据流，类似于 <a class="reference internal" href="#xdrlib.Unpacker.unpack_string" title="xdrlib.Unpacker.unpack_string"><code class="xref py py-meth docutils literal notranslate"><span class="pre">unpack_string()</span></code></a>。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_bytes">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_bytes</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_bytes" title="永久链接至目标"></a></dt>
<dd><p>解包并返回可变长度字节流，类似于 <a class="reference internal" href="#xdrlib.Unpacker.unpack_string" title="xdrlib.Unpacker.unpack_string"><code class="xref py py-meth docutils literal notranslate"><span class="pre">unpack_string()</span></code></a>。</p>
</dd></dl>
<p>下列方法支持解包数组和列表:</p>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_list">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_list</code><span class="sig-paren">(</span><em class="sig-param">unpack_item</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_list" title="永久链接至目标"></a></dt>
<dd><p>解包并返回同质条目的列表。 该列表每次解包一个元素，先解包一个无符号整数旗标。 如果旗标为 <code class="docutils literal notranslate"><span class="pre">1</span></code>，则解包条目并将其添加到列表。 旗标为 <code class="docutils literal notranslate"><span class="pre">0</span></code> 表明列表结束。 <em>unpack_item</em> 为在解包条目时调用的函数。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_farray">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_farray</code><span class="sig-paren">(</span><em class="sig-param">n</em>, <em class="sig-param">unpack_item</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_farray" title="永久链接至目标"></a></dt>
<dd><p>解包并（以列表形式）返回由同质条目构成的固定长度数组。 <em>n</em> 为期望的缓冲区内列表元素数量。 如上所述，<em>unpack_item</em> 是解包每个元素时要使用的函数。</p>
</dd></dl>
<dl class="method">
<dt id="xdrlib.Unpacker.unpack_array">
<code class="sig-prename descclassname">Unpacker.</code><code class="sig-name descname">unpack_array</code><span class="sig-paren">(</span><em class="sig-param">unpack_item</em><span class="sig-paren">)</span><a class="headerlink" href="#xdrlib.Unpacker.unpack_array" title="永久链接至目标"></a></dt>
<dd><p>解包并返回由同质条目构成的可变长度 <em>list</em>。 先将列表的长度解包为无符号整数，再像上面的 <a class="reference internal" href="#xdrlib.Unpacker.unpack_farray" title="xdrlib.Unpacker.unpack_farray"><code class="xref py py-meth docutils literal notranslate"><span class="pre">unpack_farray()</span></code></a> 一样解包每个元素。</p>
</dd></dl>
</section>
<section id="exceptions">
<span id="xdr-exceptions"></span><h2>异常<a class="headerlink" href="#exceptions" title="永久链接至标题"></a></h2>
<p>此模块中的异常会表示为类实例代码:</p>
<dl class="exception">
<dt id="xdrlib.Error">
<em class="property">exception </em><code class="sig-prename descclassname">xdrlib.</code><code class="sig-name descname">Error</code><a class="headerlink" href="#xdrlib.Error" title="永久链接至目标"></a></dt>
<dd><p>基本异常类。 <a class="reference internal" href="#xdrlib.Error" title="xdrlib.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Error</span></code></a> 具有一个公共属性 <code class="xref py py-attr docutils literal notranslate"><span class="pre">msg</span></code>，其中包含对错误的描述。</p>
</dd></dl>
<dl class="exception">
<dt id="xdrlib.ConversionError">
<em class="property">exception </em><code class="sig-prename descclassname">xdrlib.</code><code class="sig-name descname">ConversionError</code><a class="headerlink" href="#xdrlib.ConversionError" title="永久链接至目标"></a></dt>
<dd><p>从 <a class="reference internal" href="#xdrlib.Error" title="xdrlib.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">Error</span></code></a> 所派生的类。 不包含额外的实例变量。</p>
</dd></dl>
<p>以下是一个应该如何捕获这些异常的示例:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">xdrlib</span>
<span class="n">p</span> <span class="o">=</span> <span class="n">xdrlib</span><span class="o">.</span><span class="n">Packer</span><span class="p">()</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">p</span><span class="o">.</span><span class="n">pack_double</span><span class="p">(</span><span class="mf">8.01</span><span class="p">)</span>
<span class="k">except</span> <span class="n">xdrlib</span><span class="o">.</span><span class="n">ConversionError</span> <span class="k">as</span> <span class="n">instance</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">&#39;packing the double failed:&#39;</span><span class="p">,</span> <span class="n">instance</span><span class="o">.</span><span class="n">msg</span><span class="p">)</span>
</pre></div>
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