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<li><a class="reference internal" href="#">Bytes Objects</a></li>
<li><a class="reference internal" href="#pybyteswriter">PyBytesWriter</a><ul>
<li><a class="reference internal" href="#create-finish-discard">Create, Finish, Discard</a></li>
<li><a class="reference internal" href="#high-level-api">High-level API</a></li>
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<section id="bytes-objects">
<span id="bytesobjects"></span><h1>Bytes Objects<a class="headerlink" href="#bytes-objects" title="Link to this heading">¶</a></h1>
<p>These functions raise <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> when expecting a bytes parameter and
called with a non-bytes parameter.</p>
<dl class="c type" id="index-0">
<dt class="sig sig-object c" id="c.PyBytesObject">
<span class="k"><span class="pre">type</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesObject</span></span></span><a class="headerlink" href="#c.PyBytesObject" title="Link to this definition">¶</a><br /></dt>
<dd><p>This subtype of <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyObject</span></code></a> represents a Python bytes object.</p>
</dd></dl>
<dl class="c var">
<dt class="sig sig-object c" id="c.PyBytes_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_Type</span></span></span><a class="headerlink" href="#c.PyBytes_Type" title="Link 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>This instance of <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyTypeObject</span></code></a> represents the Python bytes type; it
is the same object as <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> in the Python layer.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_Check">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_Check</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.PyBytes_Check" title="Link to this definition">¶</a><br /></dt>
<dd><p>Return true if the object <em>o</em> is a bytes object or an instance of a subtype
of the bytes type. This function always succeeds.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_CheckExact">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_CheckExact</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.PyBytes_CheckExact" title="Link to this definition">¶</a><br /></dt>
<dd><p>Return true if the object <em>o</em> is a bytes object, but not an instance of a
subtype of the bytes type. This function always succeeds.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_FromString">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_FromString</span></span></span><span class="sig-paren">(</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="n"><span class="pre">v</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_FromString" title="Link to this definition">¶</a><br /></dt>
<dd><em class="refcount return_new_ref">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Return a new bytes object with a copy of the string <em>v</em> as value on success,
and <code class="docutils literal notranslate"><span class="pre">NULL</span></code> on failure. The parameter <em>v</em> must not be <code class="docutils literal notranslate"><span class="pre">NULL</span></code>; it will not be
checked.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_FromStringAndSize">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_FromStringAndSize</span></span></span><span class="sig-paren">(</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="n"><span class="pre">v</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="n"><span class="pre">len</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_FromStringAndSize" title="Link to this definition">¶</a><br /></dt>
<dd><em class="refcount return_new_ref">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Return a new bytes object with a copy of the string <em>v</em> as value and length
<em>len</em> on success, and <code class="docutils literal notranslate"><span class="pre">NULL</span></code> on failure. If <em>v</em> is <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, the contents of
the bytes object are uninitialized.</p>
<div class="versionchanged soft-deprecated">
<p><span class="versionmodified soft-deprecated"><a class="reference internal" href="../glossary.html#term-soft-deprecated">Soft deprecated</a> since version 3.15: </span>Use the <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> API instead of
<code class="docutils literal notranslate"><span class="pre">PyBytes_FromStringAndSize(NULL,</span> <span class="pre">len)</span></code>.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_FromFormat">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_FromFormat</span></span></span><span class="sig-paren">(</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="n"><span class="pre">format</span></span>, <span class="p"><span class="pre">...</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_FromFormat" title="Link to this definition">¶</a><br /></dt>
<dd><em class="refcount return_new_ref">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Take a C <code class="xref c c-func docutils literal notranslate"><span class="pre">printf()</span></code>-style <em>format</em> string and a variable number of
arguments, calculate the size of the resulting Python bytes object and return
a bytes object with the values formatted into it. The variable arguments
must be C types and must correspond exactly to the format characters in the
<em>format</em> string. The following format characters are allowed:</p>
<table class="docutils align-default">
<thead>
<tr class="row-odd"><th class="head"><p>Format Characters</p></th>
<th class="head"><p>Type</p></th>
<th class="head"><p>Comment</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">%%</span></code></p></td>
<td><p><em>n/a</em></p></td>
<td><p>The literal % character.</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">%c</span></code></p></td>
<td><p>int</p></td>
<td><p>A single byte,
represented as a C int.</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">%d</span></code></p></td>
<td><p>int</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%d")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id1" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">%u</span></code></p></td>
<td><p>unsigned int</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%u")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id2" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">%ld</span></code></p></td>
<td><p>long</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%ld")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id3" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">%lu</span></code></p></td>
<td><p>unsigned long</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%lu")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id4" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">%zd</span></code></p></td>
<td><p><a class="reference internal" href="intro.html#c.Py_ssize_t" title="Py_ssize_t"><code class="xref c c-type docutils literal notranslate"><span class="pre">Py_ssize_t</span></code></a></p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%zd")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id5" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">%zu</span></code></p></td>
<td><p>size_t</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%zu")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id6" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">%i</span></code></p></td>
<td><p>int</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%i")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id7" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">%x</span></code></p></td>
<td><p>int</p></td>
<td><p>Equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%x")</span></code>. <a class="footnote-reference brackets" href="#id9" id="id8" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">%s</span></code></p></td>
<td><p>const char*</p></td>
<td><p>A null-terminated C character
array.</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">%p</span></code></p></td>
<td><p>const void*</p></td>
<td><p>The hex representation of a C
pointer. Mostly equivalent to
<code class="docutils literal notranslate"><span class="pre">printf("%p")</span></code> except that
it is guaranteed to start with
the literal <code class="docutils literal notranslate"><span class="pre">0x</span></code> regardless
of what the platform’s
<code class="docutils literal notranslate"><span class="pre">printf</span></code> yields.</p></td>
</tr>
</tbody>
</table>
<p>An unrecognized format character causes all the rest of the format string to be
copied as-is to the result object, and any extra arguments discarded.</p>
<aside class="footnote-list brackets">
<aside class="footnote brackets" id="id9" role="doc-footnote">
<span class="label"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></span>
<span class="backrefs">(<a role="doc-backlink" href="#id1">1</a>,<a role="doc-backlink" href="#id2">2</a>,<a role="doc-backlink" href="#id3">3</a>,<a role="doc-backlink" href="#id4">4</a>,<a role="doc-backlink" href="#id5">5</a>,<a role="doc-backlink" href="#id6">6</a>,<a role="doc-backlink" href="#id7">7</a>,<a role="doc-backlink" href="#id8">8</a>)</span>
<p>For integer specifiers (d, u, ld, lu, zd, zu, i, x): the 0-conversion
flag has effect even when a precision is given.</p>
</aside>
</aside>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_FromFormatV">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_FromFormatV</span></span></span><span class="sig-paren">(</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="n"><span class="pre">format</span></span>, <span class="n"><span class="pre">va_list</span></span><span class="w"> </span><span class="n"><span class="pre">vargs</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_FromFormatV" title="Link to this definition">¶</a><br /></dt>
<dd><em class="refcount return_new_ref">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Identical to <a class="reference internal" href="#c.PyBytes_FromFormat" title="PyBytes_FromFormat"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_FromFormat()</span></code></a> except that it takes exactly two
arguments.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_FromObject">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_FromObject</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.PyBytes_FromObject" title="Link to this definition">¶</a><br /></dt>
<dd><em class="refcount return_new_ref">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><em class="threadsafety threadsafety-shared"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-shared"><span class="std std-ref">Safe for concurrent use on the same object</span></a>.</em><p>Return the bytes representation of object <em>o</em> that implements the buffer
protocol.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>If the object implements the buffer protocol, then the buffer
must not be mutated while the bytes object is being created.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_Size">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_Size</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.PyBytes_Size" title="Link 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><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Return the length of the bytes in bytes object <em>o</em>.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_GET_SIZE">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_GET_SIZE</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.PyBytes_GET_SIZE" title="Link to this definition">¶</a><br /></dt>
<dd><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Similar to <a class="reference internal" href="#c.PyBytes_Size" title="PyBytes_Size"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_Size()</span></code></a>, but without error checking.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_AsString">
<span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_AsString</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.PyBytes_AsString" title="Link 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><em class="threadsafety threadsafety-compatible"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-compatible"><span class="std std-ref">Safe to call from multiple threads with external synchronization only</span></a>.</em><p>Return a pointer to the contents of <em>o</em>. The pointer
refers to the internal buffer of <em>o</em>, which consists of <code class="docutils literal notranslate"><span class="pre">len(o)</span> <span class="pre">+</span> <span class="pre">1</span></code>
bytes. The last byte in the buffer is always null, regardless of
whether there are any other null bytes. The data must not be
modified in any way, unless the object was just created using
<code class="docutils literal notranslate"><span class="pre">PyBytes_FromStringAndSize(NULL,</span> <span class="pre">size)</span></code>. It must not be deallocated. If
<em>o</em> is not a bytes object at all, <a class="reference internal" href="#c.PyBytes_AsString" title="PyBytes_AsString"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_AsString()</span></code></a> returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code>
and raises <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>.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_AS_STRING">
<span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_AS_STRING</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">string</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_AS_STRING" title="Link to this definition">¶</a><br /></dt>
<dd><em class="threadsafety threadsafety-compatible"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-compatible"><span class="std std-ref">Safe to call from multiple threads with external synchronization only</span></a>.</em><p>Similar to <a class="reference internal" href="#c.PyBytes_AsString" title="PyBytes_AsString"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_AsString()</span></code></a>, but without error checking.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_AsStringAndSize">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_AsStringAndSize</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">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">length</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_AsStringAndSize" title="Link 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><em class="threadsafety threadsafety-compatible"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-compatible"><span class="std std-ref">Safe to call from multiple threads with external synchronization only</span></a>.</em><p>Return the null-terminated contents of the object <em>obj</em>
through the output variables <em>buffer</em> and <em>length</em>.
Returns <code class="docutils literal notranslate"><span class="pre">0</span></code> on success.</p>
<p>If <em>length</em> is <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, the bytes object
may not contain embedded null bytes;
if it does, the function returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and a <a class="reference internal" href="../library/exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> is raised.</p>
<p>The buffer refers to an internal buffer of <em>obj</em>, which includes an
additional null byte at the end (not counted in <em>length</em>). The data
must not be modified in any way, unless the object was just created using
<code class="docutils literal notranslate"><span class="pre">PyBytes_FromStringAndSize(NULL,</span> <span class="pre">size)</span></code>. It must not be deallocated. If
<em>obj</em> is not a bytes object at all, <a class="reference internal" href="#c.PyBytes_AsStringAndSize" title="PyBytes_AsStringAndSize"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_AsStringAndSize()</span></code></a>
returns <code class="docutils literal notranslate"><span class="pre">-1</span></code> and raises <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>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.5: </span>Previously, <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> was raised when embedded null bytes were
encountered in the bytes object.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_Concat">
<span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_Concat</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="p"><span class="pre">*</span></span><span class="n"><span class="pre">bytes</span></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">newpart</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_Concat" title="Link 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><em class="threadsafety threadsafety-shared"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-shared"><span class="std std-ref">Safe for concurrent use on the same object</span></a>.</em><p>Create a new bytes object in <em>*bytes</em> containing the contents of <em>newpart</em>
appended to <em>bytes</em>; the caller will own the new reference.
The reference to the old value of <em>bytes</em> will be “<a class="reference internal" href="../glossary.html#term-steal"><span class="xref std std-term">stolen</span></a>”.
If the new object cannot be created, the old reference to <em>bytes</em> will still
be “stolen”, the value of <em>*bytes</em> will be set to <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, and
the appropriate exception will be set.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>If <em>newpart</em> implements the buffer protocol, then the buffer
must not be mutated while the new bytes object is being created.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_ConcatAndDel">
<span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytes_ConcatAndDel</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="p"><span class="pre">*</span></span><span class="n"><span class="pre">bytes</span></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">newpart</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_ConcatAndDel" title="Link 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><em class="threadsafety threadsafety-shared"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-shared"><span class="std std-ref">Safe for concurrent use on the same object</span></a>.</em><p>Create a new bytes object in <em>*bytes</em> containing the contents of <em>newpart</em>
appended to <em>bytes</em>. This version releases the <a class="reference internal" href="../glossary.html#term-strong-reference"><span class="xref std std-term">strong reference</span></a>
to <em>newpart</em> (i.e. decrements its reference count).</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>If <em>newpart</em> implements the buffer protocol, then the buffer
must not be mutated while the new bytes object is being created.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_Join">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_Join</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">sep</span></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">iterable</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_Join" title="Link to this definition">¶</a><br /></dt>
<dd><em class="threadsafety threadsafety-shared"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-shared"><span class="std std-ref">Safe for concurrent use on the same object</span></a>.</em><p>Similar to <code class="docutils literal notranslate"><span class="pre">sep.join(iterable)</span></code> in Python.</p>
<p><em>sep</em> must be Python <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.
(Note that <a class="reference internal" href="unicode.html#c.PyUnicode_Join" title="PyUnicode_Join"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyUnicode_Join()</span></code></a> accepts <code class="docutils literal notranslate"><span class="pre">NULL</span></code> separator and treats
it as a space, whereas <a class="reference internal" href="#c.PyBytes_Join" title="PyBytes_Join"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_Join()</span></code></a> doesn’t accept <code class="docutils literal notranslate"><span class="pre">NULL</span></code>
separator.)</p>
<p><em>iterable</em> must be an iterable object yielding objects that implement the
<a class="reference internal" href="buffer.html#bufferobjects"><span class="std std-ref">buffer protocol</span></a>.</p>
<p>On success, return a new <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.
On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.14.</span></p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>If <em>iterable</em> objects implement the buffer protocol, then the buffers
must not be mutated while the new bytes object is being created.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c._PyBytes_Resize">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">_PyBytes_Resize</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="p"><span class="pre">*</span></span><span class="n"><span class="pre">bytes</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="n"><span class="pre">newsize</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c._PyBytes_Resize" title="Link to this definition">¶</a><br /></dt>
<dd><em class="threadsafety threadsafety-distinct"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-distinct"><span class="std std-ref">Safe to call without external synchronization on distinct objects</span></a>.</em><p>Resize a bytes object. <em>newsize</em> will be the new length of the bytes object.
You can think of it as creating a new bytes object and destroying the old
one, only more efficiently.
Pass the address of an
existing bytes object as an lvalue (it may be written into), and the new size
desired. On success, <em>*bytes</em> holds the resized bytes object and <code class="docutils literal notranslate"><span class="pre">0</span></code> is
returned; the address in <em>*bytes</em> may differ from its input value. If the
reallocation fails, the original bytes object at <em>*bytes</em> is deallocated,
<em>*bytes</em> is set to <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, <a class="reference internal" href="../library/exceptions.html#MemoryError" title="MemoryError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">MemoryError</span></code></a> is set, and <code class="docutils literal notranslate"><span class="pre">-1</span></code> is
returned.</p>
<div class="versionchanged soft-deprecated">
<p><span class="versionmodified soft-deprecated"><a class="reference internal" href="../glossary.html#term-soft-deprecated">Soft deprecated</a> since version 3.15: </span>Use the <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> API instead.</p>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_Repr">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_Repr</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">bytes</span></span>, <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">smartquotes</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_Repr" title="Link 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><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Get the string representation of <em>bytes</em>. This function is currently used to
implement <code class="xref py py-meth docutils literal notranslate"><span class="pre">bytes.__repr__()</span></code> in Python.</p>
<p>This function does not do type checking; it is undefined behavior to pass
<em>bytes</em> as a non-bytes object or <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<p>If <em>smartquotes</em> is true, the representation will use a double-quoted string
instead of single-quoted string when single-quotes are present in <em>bytes</em>.
For example, the byte string <code class="docutils literal notranslate"><span class="pre">'Python'</span></code> would be represented as
<code class="docutils literal notranslate"><span class="pre">b"'Python'"</span></code> when <em>smartquotes</em> is true, or <code class="docutils literal notranslate"><span class="pre">b'\'Python\''</span></code> when it is
false.</p>
<p>On success, this function returns a <a class="reference internal" href="../glossary.html#term-strong-reference"><span class="xref std std-term">strong reference</span></a> to a
<a class="reference internal" href="../library/stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a> object containing the representation. On failure, this
returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code> with an exception set.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytes_DecodeEscape">
<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="sig-name descname"><span class="n"><span class="pre">PyBytes_DecodeEscape</span></span></span><span class="sig-paren">(</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="n"><span class="pre">s</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="n"><span class="pre">len</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="n"><span class="pre">errors</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="n"><span class="pre">unicode</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="n"><span class="pre">recode_encoding</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytes_DecodeEscape" title="Link 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><em class="threadsafety threadsafety-atomic"> Thread safety: <a class="reference internal" href="../library/threadsafety.html#threadsafety-level-atomic"><span class="std std-ref">Atomic</span></a>.</em><p>Unescape a backslash-escaped string <em>s</em>. <em>s</em> must not be <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.
<em>len</em> must be the size of <em>s</em>.</p>
<p><em>errors</em> must be one of <code class="docutils literal notranslate"><span class="pre">"strict"</span></code>, <code class="docutils literal notranslate"><span class="pre">"replace"</span></code>, or <code class="docutils literal notranslate"><span class="pre">"ignore"</span></code>. If
<em>errors</em> is <code class="docutils literal notranslate"><span class="pre">NULL</span></code>, then <code class="docutils literal notranslate"><span class="pre">"strict"</span></code> is used by default.</p>
<p>On success, this function returns a <a class="reference internal" href="../glossary.html#term-strong-reference"><span class="xref std std-term">strong reference</span></a> to a Python
<a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object containing the unescaped string. On failure, this
function returns <code class="docutils literal notranslate"><span class="pre">NULL</span></code> with an exception set.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.9: </span><em>unicode</em> and <em>recode_encoding</em> are now unused.</p>
</div>
</dd></dl>
</section>
<section id="pybyteswriter">
<span id="id10"></span><h1>PyBytesWriter<a class="headerlink" href="#pybyteswriter" title="Link to this heading">¶</a></h1>
<p>The <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> API can be used to create a Python <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>
object.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.15.</span></p>
</div>
<dl class="c type">
<dt class="sig sig-object c" id="c.PyBytesWriter">
<span class="k"><span class="pre">type</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter</span></span></span><a class="headerlink" href="#c.PyBytesWriter" title="Link to this definition">¶</a><br /></dt>
<dd><p>A bytes writer instance.</p>
<p>The API is <strong>not thread safe</strong>: a writer should only be used by a single
thread at the same time.</p>
<p>The instance must be destroyed by <a class="reference internal" href="#c.PyBytesWriter_Finish" title="PyBytesWriter_Finish"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Finish()</span></code></a> on
success, or <a class="reference internal" href="#c.PyBytesWriter_Discard" title="PyBytesWriter_Discard"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Discard()</span></code></a> on error.</p>
</dd></dl>
<section id="create-finish-discard">
<h2>Create, Finish, Discard<a class="headerlink" href="#create-finish-discard" title="Link to this heading">¶</a></h2>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_Create">
<a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_Create</span></span></span><span class="sig-paren">(</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="n"><span class="pre">size</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_Create" title="Link to this definition">¶</a><br /></dt>
<dd><p>Create a <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> to write <em>size</em> bytes.</p>
<p>If <em>size</em> is greater than zero, allocate <em>size</em> bytes, and set the
writer size to <em>size</em>. The caller is responsible to write <em>size</em>
bytes using <a class="reference internal" href="#c.PyBytesWriter_GetData" title="PyBytesWriter_GetData"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_GetData()</span></code></a>.
This function does not overallocate.</p>
<p>On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<p><em>size</em> must be positive or zero.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_Finish">
<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="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_Finish</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_Finish" title="Link to this definition">¶</a><br /></dt>
<dd><p>Finish a <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> created by
<a class="reference internal" href="#c.PyBytesWriter_Create" title="PyBytesWriter_Create"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Create()</span></code></a>.</p>
<p>On success, return a Python <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.
On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<p>The writer instance is invalid after the call in any case.
No API can be called on the writer after <a class="reference internal" href="#c.PyBytesWriter_Finish" title="PyBytesWriter_Finish"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Finish()</span></code></a>.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_FinishWithSize">
<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="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_FinishWithSize</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">size</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_FinishWithSize" title="Link to this definition">¶</a><br /></dt>
<dd><p>Similar to <a class="reference internal" href="#c.PyBytesWriter_Finish" title="PyBytesWriter_Finish"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Finish()</span></code></a>, but resize the writer
to <em>size</em> bytes before creating the <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_FinishWithPointer">
<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="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_FinishWithPointer</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">buf</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_FinishWithPointer" title="Link to this definition">¶</a><br /></dt>
<dd><p>Similar to <a class="reference internal" href="#c.PyBytesWriter_Finish" title="PyBytesWriter_Finish"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Finish()</span></code></a>, but resize the writer
using <em>buf</em> pointer before creating the <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object.</p>
<p>Set an exception and return <code class="docutils literal notranslate"><span class="pre">NULL</span></code> if <em>buf</em> pointer is outside the
internal buffer bounds.</p>
<p>Function pseudo-code:</p>
<div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="n">Py_ssize_t</span><span class="w"> </span><span class="n">size</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="kt">char</span><span class="o">*</span><span class="p">)</span><span class="n">buf</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="p">(</span><span class="kt">char</span><span class="o">*</span><span class="p">)</span><span class="n">PyBytesWriter_GetData</span><span class="p">(</span><span class="n">writer</span><span class="p">);</span>
<span class="k">return</span><span class="w"> </span><span class="n">PyBytesWriter_FinishWithSize</span><span class="p">(</span><span class="n">writer</span><span class="p">,</span><span class="w"> </span><span class="n">size</span><span class="p">);</span>
</pre></div>
</div>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_Discard">
<span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_Discard</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_Discard" title="Link to this definition">¶</a><br /></dt>
<dd><p>Discard a <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> created by <a class="reference internal" href="#c.PyBytesWriter_Create" title="PyBytesWriter_Create"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Create()</span></code></a>.</p>
<p>Do nothing if <em>writer</em> is <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<p>The writer instance is invalid after the call.
No API can be called on the writer after <a class="reference internal" href="#c.PyBytesWriter_Discard" title="PyBytesWriter_Discard"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Discard()</span></code></a>.</p>
</dd></dl>
</section>
<section id="high-level-api">
<h2>High-level API<a class="headerlink" href="#high-level-api" title="Link to this heading">¶</a></h2>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_WriteBytes">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_WriteBytes</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">bytes</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="n"><span class="pre">size</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_WriteBytes" title="Link to this definition">¶</a><br /></dt>
<dd><p>Grow the <em>writer</em> internal buffer by <em>size</em> bytes,
write <em>size</em> bytes of <em>bytes</em> at the <em>writer</em> end,
and add <em>size</em> to the <em>writer</em> size.</p>
<p>If <em>size</em> is equal to <code class="docutils literal notranslate"><span class="pre">-1</span></code>, call <code class="docutils literal notranslate"><span class="pre">strlen(bytes)</span></code> to get the
string length.</p>
<p>On success, return <code class="docutils literal notranslate"><span class="pre">0</span></code>.
On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">-1</span></code>.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_Format">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_Format</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">format</span></span>, <span class="p"><span class="pre">...</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_Format" title="Link to this definition">¶</a><br /></dt>
<dd><p>Similar to <a class="reference internal" href="#c.PyBytes_FromFormat" title="PyBytes_FromFormat"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytes_FromFormat()</span></code></a>, but write the output directly at
the writer end. Grow the writer internal buffer on demand. Then add the
written size to the writer size.</p>
<p>On success, return <code class="docutils literal notranslate"><span class="pre">0</span></code>.
On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">-1</span></code>.</p>
</dd></dl>
</section>
<section id="getters">
<h2>Getters<a class="headerlink" href="#getters" title="Link to this heading">¶</a></h2>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_GetSize">
<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="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_GetSize</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_GetSize" title="Link to this definition">¶</a><br /></dt>
<dd><p>Get the writer size.</p>
<p>The function does not invalidate pointers returned by
<a class="reference internal" href="#c.PyBytesWriter_GetData" title="PyBytesWriter_GetData"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_GetData()</span></code></a>.</p>
<p>The function cannot fail.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_GetData">
<span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_GetData</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_GetData" title="Link to this definition">¶</a><br /></dt>
<dd><p>Get the writer data: start of the internal buffer.</p>
<p>The pointer remains valid until a <a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><code class="xref c c-type docutils literal notranslate"><span class="pre">PyBytesWriter</span></code></a> function other
than <a class="reference internal" href="#c.PyBytesWriter_GetData" title="PyBytesWriter_GetData"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_GetData()</span></code></a> or <a class="reference internal" href="#c.PyBytesWriter_GetSize" title="PyBytesWriter_GetSize"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_GetSize()</span></code></a> is
called on <em>writer</em>.</p>
<p>The function cannot fail.</p>
</dd></dl>
</section>
<section id="low-level-api">
<h2>Low-level API<a class="headerlink" href="#low-level-api" title="Link to this heading">¶</a></h2>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_Resize">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_Resize</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">size</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_Resize" title="Link to this definition">¶</a><br /></dt>
<dd><p>Resize the writer to <em>size</em> bytes. It can be used to enlarge or to
shrink the writer.
This function typically overallocates to achieve amortized performance when
resizing multiple times.</p>
<p>Newly allocated bytes are left uninitialized.</p>
<p>On success, return <code class="docutils literal notranslate"><span class="pre">0</span></code>.
On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">-1</span></code>.</p>
<p><em>size</em> must be positive or zero.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_Grow">
<span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_Grow</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">grow</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_Grow" title="Link to this definition">¶</a><br /></dt>
<dd><p>Resize the writer by adding <em>grow</em> bytes to the current writer size.
This function typically overallocates to achieve amortized performance when
resizing multiple times.</p>
<p>Newly allocated bytes are left uninitialized.</p>
<p>On success, return <code class="docutils literal notranslate"><span class="pre">0</span></code>.
On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">-1</span></code>.</p>
<p><em>size</em> can be negative to shrink the writer.</p>
</dd></dl>
<dl class="c function">
<dt class="sig sig-object c" id="c.PyBytesWriter_GrowAndUpdatePointer">
<span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyBytesWriter_GrowAndUpdatePointer</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="#c.PyBytesWriter" title="PyBytesWriter"><span class="n"><span class="pre">PyBytesWriter</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">writer</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="n"><span class="pre">size</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="n"><span class="pre">buf</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyBytesWriter_GrowAndUpdatePointer" title="Link to this definition">¶</a><br /></dt>
<dd><p>Similar to <a class="reference internal" href="#c.PyBytesWriter_Grow" title="PyBytesWriter_Grow"><code class="xref c c-func docutils literal notranslate"><span class="pre">PyBytesWriter_Grow()</span></code></a>, but update also the <em>buf</em>
pointer.</p>
<p>The <em>buf</em> pointer is moved if the internal buffer is moved in memory.
The <em>buf</em> relative position within the internal buffer is left
unchanged.</p>
<p>On error, set an exception and return <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<p><em>buf</em> must not be <code class="docutils literal notranslate"><span class="pre">NULL</span></code>.</p>
<p>Function pseudo-code:</p>
<div class="highlight-c notranslate"><div class="highlight"><pre><span></span><span class="n">Py_ssize_t</span><span class="w"> </span><span class="n">pos</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="p">(</span><span class="kt">char</span><span class="o">*</span><span class="p">)</span><span class="n">buf</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="p">(</span><span class="kt">char</span><span class="o">*</span><span class="p">)</span><span class="n">PyBytesWriter_GetData</span><span class="p">(</span><span class="n">writer</span><span class="p">);</span>
<span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">PyBytesWriter_Grow</span><span class="p">(</span><span class="n">writer</span><span class="p">,</span><span class="w"> </span><span class="n">size</span><span class="p">)</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="mi">0</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nb">NULL</span><span class="p">;</span>
<span class="p">}</span>
<span class="k">return</span><span class="w"> </span><span class="p">(</span><span class="kt">char</span><span class="o">*</span><span class="p">)</span><span class="n">PyBytesWriter_GetData</span><span class="p">(</span><span class="n">writer</span><span class="p">)</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">pos</span><span class="p">;</span>
</pre></div>
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<li><a class="reference internal" href="#">Bytes Objects</a></li>
<li><a class="reference internal" href="#pybyteswriter">PyBytesWriter</a><ul>
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