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<section id="allocating-objects-on-the-heap">
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<span id="allocating-objects"></span><h1>在堆上分配对象<a class="headerlink" href="#allocating-objects-on-the-heap" title="永久链接至标题">¶</a></h1>
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<dl class="function">
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<dt id="c._PyObject_New">
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<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">_PyObject_New</code><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em><span class="sig-paren">)</span><a class="headerlink" href="#c._PyObject_New" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: New reference.</em></dd></dl>
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<dl class="function">
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<dt id="c._PyObject_NewVar">
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<a class="reference internal" href="structures.html#c.PyVarObject" title="PyVarObject">PyVarObject</a>* <code class="sig-name descname">_PyObject_NewVar</code><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em>, Py_ssize_t<em> size</em><span class="sig-paren">)</span><a class="headerlink" href="#c._PyObject_NewVar" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: New reference.</em></dd></dl>
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<dl class="function">
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<dt id="c.PyObject_Init">
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<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="sig-name descname">PyObject_Init</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em> *op</em>, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_Init" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: Borrowed reference.</em><p>为新分配的对象 <em>op</em> 初始化它的类型和引用。返回初始化后的对象。如果 <em>type</em> 声明这个对象参与循环垃圾检测，那么这个对象会被添加进垃圾检测的对象集中。这个对象的其他字段不会被影响。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyObject_InitVar">
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<a class="reference internal" href="structures.html#c.PyVarObject" title="PyVarObject">PyVarObject</a>* <code class="sig-name descname">PyObject_InitVar</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyVarObject" title="PyVarObject">PyVarObject</a><em> *op</em>, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em>, Py_ssize_t<em> size</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_InitVar" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: Borrowed reference.</em><p>它的功能和 <a class="reference internal" href="#c.PyObject_Init" title="PyObject_Init"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_Init()</span></code></a> 一样，并且会初始化变量大小对象的长度信息。</p>
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</dd></dl>
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<dl class="function">
|
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<dt id="c.PyObject_New">
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TYPE* <code class="sig-name descname">PyObject_New</code><span class="sig-paren">(</span>TYPE, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_New" title="永久链接至目标">¶</a></dt>
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<dd><em class="refcount">Return value: New reference.</em><p>使用 C 结构类型 <em>TYPE</em> 和 Python 类型对象 <em>type</em> 分配一个新的 Python 对象。 未在该 Python 对象头中定义的字段不会被初始化；对象的引用计数将为一。 内存分配大小由 type 对象的 <a class="reference internal" href="typeobj.html#c.PyTypeObject.tp_basicsize" title="PyTypeObject.tp_basicsize"><code class="xref c c-member docutils literal notranslate"><span class="pre">tp_basicsize</span></code></a> 字段来确定。</p>
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</dd></dl>
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<dl class="function">
|
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<dt id="c.PyObject_NewVar">
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TYPE* <code class="sig-name descname">PyObject_NewVar</code><span class="sig-paren">(</span>TYPE, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em> *type</em>, Py_ssize_t<em> size</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_NewVar" title="永久链接至目标">¶</a></dt>
|
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<dd><em class="refcount">Return value: New reference.</em><p>使用C的数据结构类型 <em>TYPE</em> 和Python的类型对象 <em>type</em> 分配一个新的Python对象。Python对象头文件中没有定义的字段不会被初始化。被分配的内存空间预留了 <em>TYPE</em> 结构加 <em>type</em> 对象中 <a class="reference internal" href="typeobj.html#c.PyTypeObject.tp_itemsize" title="PyTypeObject.tp_itemsize"><code class="xref c c-member docutils literal notranslate"><span class="pre">tp_itemsize</span></code></a> 字段提供的 <em>size</em> 字段的值。这对于实现类似元组这种能够在构造期决定自己大小的对象是很实用的。将字段的数组嵌入到相同的内存分配中可以减少内存分配的次数，这提高了内存分配的效率。</p>
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</dd></dl>
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<dl class="function">
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<dt id="c.PyObject_Del">
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void <code class="sig-name descname">PyObject_Del</code><span class="sig-paren">(</span>void<em> *op</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_Del" title="永久链接至目标">¶</a></dt>
|
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<dd><p>释放由 <a class="reference internal" href="#c.PyObject_New" title="PyObject_New"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_New()</span></code></a> 或者 <a class="reference internal" href="#c.PyObject_NewVar" title="PyObject_NewVar"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_NewVar()</span></code></a> 分配内存的对象。这通常由对象的type字段定义的 <a class="reference internal" href="typeobj.html#c.PyTypeObject.tp_dealloc" title="PyTypeObject.tp_dealloc"><code class="xref c c-member docutils literal notranslate"><span class="pre">tp_dealloc</span></code></a> 处理函数来调用。调用这个函数以后op对象中的字段都不可以被访问，因为原分配的内存空间已不再是一个有效的Python对象。</p>
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<dt id="c._Py_NoneStruct">
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<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a> <code class="sig-name descname">_Py_NoneStruct</code><a class="headerlink" href="#c._Py_NoneStruct" title="永久链接至目标">¶</a></dt>
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<dd><p>这个对象是像 <code class="docutils literal notranslate"><span class="pre">None</span></code> 一样的 Python 对象。它可以使用 <a class="reference internal" href="none.html#c.Py_None" title="Py_None"><code class="xref c c-macro docutils literal notranslate"><span class="pre">Py_None</span></code></a> 宏访问，该宏的拿到指向该对象的指针。</p>
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<div class="admonition seealso">
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<dt><a class="reference internal" href="module.html#c.PyModule_Create" title="PyModule_Create"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyModule_Create()</span></code></a></dt><dd><p>分配内存和创建扩展模块</p>
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