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  <section id="old-buffer-protocol">
<h1>Old Buffer Protocol<a class="headerlink" href="#old-buffer-protocol" title="Permalink to this headline">¶</a></h1>
<div class="deprecated">
<p><span class="versionmodified deprecated">Deprecated since version 3.0.</span></p>
</div>
<p>These functions were part of the “old buffer protocol” API in Python 2.
In Python 3, this protocol doesn’t exist anymore but the functions are still
exposed to ease porting 2.x code.  They act as a compatibility wrapper
around the <a class="reference internal" href="buffer.html#bufferobjects"><span class="std std-ref">new buffer protocol</span></a>, but they don’t give
you control over the lifetime of the resources acquired when a buffer is
exported.</p>
<p>Therefore, it is recommended that you call <a class="reference internal" href="buffer.html#c.PyObject_GetBuffer" title="PyObject_GetBuffer"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetBuffer()</span></code></a>
(or the <code class="docutils literal notranslate"><span class="pre">y*</span></code> or <code class="docutils literal notranslate"><span class="pre">w*</span></code> <a class="reference internal" href="arg.html#arg-parsing"><span class="std std-ref">format codes</span></a> with the
<a class="reference internal" href="arg.html#c.PyArg_ParseTuple" title="PyArg_ParseTuple"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyArg_ParseTuple()</span></code></a> family of functions) to get a buffer view over
an object, and <a class="reference internal" href="buffer.html#c.PyBuffer_Release" title="PyBuffer_Release"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBuffer_Release()</span></code></a> when the buffer view can be released.</p>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyObject_AsCharBuffer">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyObject_AsCharBuffer</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">obj</span></span>, <span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer</span></span>, <a class="reference internal" href="intro.html#c.Py_ssize_t" title="Py_ssize_t"><span class="n"><span class="pre">Py_ssize_t</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer_len</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsCharBuffer" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Returns a pointer to a read-only memory location usable as character-based
input.  The <em>obj</em> argument must support the single-segment character buffer
interface.  On success, returns <code class="docutils literal notranslate"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location
and <em>buffer_len</em> to the buffer length.  Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and sets a
<a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> on error.</p>
</dd></dl>

<dl class="c function">
<dt class="sig sig-object c" id="c.PyObject_AsReadBuffer">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyObject_AsReadBuffer</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">obj</span></span>, <span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer</span></span>, <a class="reference internal" href="intro.html#c.Py_ssize_t" title="Py_ssize_t"><span class="n"><span class="pre">Py_ssize_t</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer_len</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsReadBuffer" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Returns a pointer to a read-only memory location containing arbitrary data.
The <em>obj</em> argument must support the single-segment readable buffer
interface.  On success, returns <code class="docutils literal notranslate"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location
and <em>buffer_len</em> to the buffer length.  Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and sets a
<a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> on error.</p>
</dd></dl>

<dl class="c function">
<dt class="sig sig-object c" id="c.PyObject_CheckReadBuffer">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyObject_CheckReadBuffer</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">o</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_CheckReadBuffer" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Returns <code class="docutils literal notranslate"><span class="pre">1</span></code> if <em>o</em> supports the single-segment readable buffer interface.
Otherwise returns <code class="docutils literal notranslate"><span class="pre">0</span></code>.  This function always succeeds.</p>
<p>Note that this function tries to get and release a buffer, and exceptions
which occur while calling corresponding functions will get suppressed.
To get error reporting use <a class="reference internal" href="buffer.html#c.PyObject_GetBuffer" title="PyObject_GetBuffer"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyObject_GetBuffer()</span></code></a> instead.</p>
</dd></dl>

<dl class="c function">
<dt class="sig sig-object c" id="c.PyObject_AsWriteBuffer">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyObject_AsWriteBuffer</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">obj</span></span>, <span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer</span></span>, <a class="reference internal" href="intro.html#c.Py_ssize_t" title="Py_ssize_t"><span class="n"><span class="pre">Py_ssize_t</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer_len</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsWriteBuffer" title="Permalink to this definition">¶</a><br /></dt>
<dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>Returns a pointer to a writable memory location.  The <em>obj</em> argument must
support the single-segment, character buffer interface.  On success,
returns <code class="docutils literal notranslate"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the
buffer length.  Returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and sets a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> on error.</p>
</dd></dl>

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