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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>File Objects — Python 2.7.5 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '2.7.5', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.5 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="top" title="Python 2.7.5 documentation" href="../index.html" /> <link rel="up" title="Concrete Objects Layer" href="concrete.html" /> <link rel="next" title="Module Objects" href="module.html" /> <link rel="prev" title="Method Objects" href="method.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </head> <body> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="module.html" title="Module Objects" accesskey="N">next</a> |</li> <li class="right" > <a href="method.html" title="Method Objects" accesskey="P">previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >Python/C API Reference Manual</a> »</li> <li><a href="concrete.html" accesskey="U">Concrete Objects Layer</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="file-objects"> <span id="fileobjects"></span><h1>File Objects<a class="headerlink" href="#file-objects" title="Permalink to this headline">¶</a></h1> <p id="index-0">Python’s built-in file objects are implemented entirely on the <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt> support from the C standard library. This is an implementation detail and may change in future releases of Python.</p> <dl class="type"> <dt id="PyFileObject"> <tt class="descname">PyFileObject</tt><a class="headerlink" href="#PyFileObject" title="Permalink to this definition">¶</a></dt> <dd><p>This subtype of <a class="reference internal" href="structures.html#PyObject" title="PyObject"><tt class="xref c c-type docutils literal"><span class="pre">PyObject</span></tt></a> represents a Python file object.</p> </dd></dl> <dl class="var"> <dt id="PyFile_Type"> <a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject">PyTypeObject</a> <tt class="descname">PyFile_Type</tt><a class="headerlink" href="#PyFile_Type" title="Permalink to this definition">¶</a></dt> <dd><p id="index-1">This instance of <a class="reference internal" href="type.html#PyTypeObject" title="PyTypeObject"><tt class="xref c c-type docutils literal"><span class="pre">PyTypeObject</span></tt></a> represents the Python file type. This is exposed to Python programs as <tt class="docutils literal"><span class="pre">file</span></tt> and <tt class="docutils literal"><span class="pre">types.FileType</span></tt>.</p> </dd></dl> <dl class="function"> <dt id="PyFile_Check"> int <tt class="descname">PyFile_Check</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_Check" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if its argument is a <a class="reference internal" href="#PyFileObject" title="PyFileObject"><tt class="xref c c-type docutils literal"><span class="pre">PyFileObject</span></tt></a> or a subtype of <a class="reference internal" href="#PyFileObject" title="PyFileObject"><tt class="xref c c-type docutils literal"><span class="pre">PyFileObject</span></tt></a>.</p> <p class="versionchanged"> <span class="versionmodified">Changed in version 2.2: </span>Allowed subtypes to be accepted.</p> </dd></dl> <dl class="function"> <dt id="PyFile_CheckExact"> int <tt class="descname">PyFile_CheckExact</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_CheckExact" title="Permalink to this definition">¶</a></dt> <dd><p>Return true if its argument is a <a class="reference internal" href="#PyFileObject" title="PyFileObject"><tt class="xref c c-type docutils literal"><span class="pre">PyFileObject</span></tt></a>, but not a subtype of <a class="reference internal" href="#PyFileObject" title="PyFileObject"><tt class="xref c c-type docutils literal"><span class="pre">PyFileObject</span></tt></a>.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.2.</span></p> </dd></dl> <dl class="function"> <dt id="PyFile_FromString"> <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyFile_FromString</tt><big>(</big>char<em> *filename</em>, char<em> *mode</em><big>)</big><a class="headerlink" href="#PyFile_FromString" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-2">On success, return a new file object that is opened on the file given by <em>filename</em>, with a file mode given by <em>mode</em>, where <em>mode</em> has the same semantics as the standard C routine <tt class="xref c c-func docutils literal"><span class="pre">fopen()</span></tt>. On failure, return <em>NULL</em>.</p> </dd></dl> <dl class="function"> <dt id="PyFile_FromFile"> <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyFile_FromFile</tt><big>(</big>FILE<em> *fp</em>, char<em> *name</em>, char<em> *mode</em>, int<em> (*close)(FILE*)</em><big>)</big><a class="headerlink" href="#PyFile_FromFile" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p>Create a new <a class="reference internal" href="#PyFileObject" title="PyFileObject"><tt class="xref c c-type docutils literal"><span class="pre">PyFileObject</span></tt></a> from the already-open standard C file pointer, <em>fp</em>. The function <em>close</em> will be called when the file should be closed. Return <em>NULL</em> and close the file using <em>close</em> on failure. <em>close</em> is optional and can be set to <em>NULL</em>.</p> </dd></dl> <dl class="function"> <dt id="PyFile_AsFile"> FILE* <tt class="descname">PyFile_AsFile</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_AsFile" title="Permalink to this definition">¶</a></dt> <dd><p>Return the file object associated with <em>p</em> as a <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt>.</p> <p>If the caller will ever use the returned <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt> object while the <a class="reference internal" href="../glossary.html#term-gil"><em class="xref std std-term">GIL</em></a> is released it must also call the <a class="reference internal" href="#PyFile_IncUseCount" title="PyFile_IncUseCount"><tt class="xref c c-func docutils literal"><span class="pre">PyFile_IncUseCount()</span></tt></a> and <a class="reference internal" href="#PyFile_DecUseCount" title="PyFile_DecUseCount"><tt class="xref c c-func docutils literal"><span class="pre">PyFile_DecUseCount()</span></tt></a> functions described below as appropriate.</p> </dd></dl> <dl class="function"> <dt id="PyFile_IncUseCount"> void <tt class="descname">PyFile_IncUseCount</tt><big>(</big><a class="reference internal" href="#PyFileObject" title="PyFileObject">PyFileObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_IncUseCount" title="Permalink to this definition">¶</a></dt> <dd><p>Increments the PyFileObject’s internal use count to indicate that the underlying <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt> is being used. This prevents Python from calling f_close() on it from another thread. Callers of this must call <a class="reference internal" href="#PyFile_DecUseCount" title="PyFile_DecUseCount"><tt class="xref c c-func docutils literal"><span class="pre">PyFile_DecUseCount()</span></tt></a> when they are finished with the <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt>. Otherwise the file object will never be closed by Python.</p> <p>The <a class="reference internal" href="../glossary.html#term-gil"><em class="xref std std-term">GIL</em></a> must be held while calling this function.</p> <p>The suggested use is to call this after <a class="reference internal" href="#PyFile_AsFile" title="PyFile_AsFile"><tt class="xref c c-func docutils literal"><span class="pre">PyFile_AsFile()</span></tt></a> and before you release the GIL:</p> <div class="highlight-c"><div class="highlight"><pre><span class="kt">FILE</span> <span class="o">*</span><span class="n">fp</span> <span class="o">=</span> <span class="n">PyFile_AsFile</span><span class="p">(</span><span class="n">p</span><span class="p">);</span> <span class="n">PyFile_IncUseCount</span><span class="p">(</span><span class="n">p</span><span class="p">);</span> <span class="cm">/* ... */</span> <span class="n">Py_BEGIN_ALLOW_THREADS</span> <span class="n">do_something</span><span class="p">(</span><span class="n">fp</span><span class="p">);</span> <span class="n">Py_END_ALLOW_THREADS</span> <span class="cm">/* ... */</span> <span class="n">PyFile_DecUseCount</span><span class="p">(</span><span class="n">p</span><span class="p">);</span> </pre></div> </div> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="function"> <dt id="PyFile_DecUseCount"> void <tt class="descname">PyFile_DecUseCount</tt><big>(</big><a class="reference internal" href="#PyFileObject" title="PyFileObject">PyFileObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_DecUseCount" title="Permalink to this definition">¶</a></dt> <dd><p>Decrements the PyFileObject’s internal unlocked_count member to indicate that the caller is done with its own use of the <tt class="xref c c-type docutils literal"><span class="pre">FILE*</span></tt>. This may only be called to undo a prior call to <a class="reference internal" href="#PyFile_IncUseCount" title="PyFile_IncUseCount"><tt class="xref c c-func docutils literal"><span class="pre">PyFile_IncUseCount()</span></tt></a>.</p> <p>The <a class="reference internal" href="../glossary.html#term-gil"><em class="xref std std-term">GIL</em></a> must be held while calling this function (see the example above).</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="function"> <dt id="PyFile_GetLine"> <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyFile_GetLine</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em>, int<em> n</em><big>)</big><a class="headerlink" href="#PyFile_GetLine" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: New reference.</em><p id="index-3">Equivalent to <tt class="docutils literal"><span class="pre">p.readline([n])</span></tt>, this function reads one line from the object <em>p</em>. <em>p</em> may be a file object or any object with a <a class="reference internal" href="../library/readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><tt class="xref py py-meth docutils literal"><span class="pre">readline()</span></tt></a> method. If <em>n</em> is <tt class="docutils literal"><span class="pre">0</span></tt>, exactly one line is read, regardless of the length of the line. If <em>n</em> is greater than <tt class="docutils literal"><span class="pre">0</span></tt>, no more than <em>n</em> bytes will be read from the file; a partial line can be returned. In both cases, an empty string is returned if the end of the file is reached immediately. If <em>n</em> is less than <tt class="docutils literal"><span class="pre">0</span></tt>, however, one line is read regardless of length, but <a class="reference internal" href="../library/exceptions.html#exceptions.EOFError" title="exceptions.EOFError"><tt class="xref py py-exc docutils literal"><span class="pre">EOFError</span></tt></a> is raised if the end of the file is reached immediately.</p> </dd></dl> <dl class="function"> <dt id="PyFile_Name"> <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyFile_Name</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_Name" title="Permalink to this definition">¶</a></dt> <dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the name of the file specified by <em>p</em> as a string object.</p> </dd></dl> <dl class="function"> <dt id="PyFile_SetBufSize"> void <tt class="descname">PyFile_SetBufSize</tt><big>(</big><a class="reference internal" href="#PyFileObject" title="PyFileObject">PyFileObject</a><em> *p</em>, int<em> n</em><big>)</big><a class="headerlink" href="#PyFile_SetBufSize" title="Permalink to this definition">¶</a></dt> <dd><p id="index-4">Available on systems with <tt class="xref c c-func docutils literal"><span class="pre">setvbuf()</span></tt> only. This should only be called immediately after file object creation.</p> </dd></dl> <dl class="function"> <dt id="PyFile_SetEncoding"> int <tt class="descname">PyFile_SetEncoding</tt><big>(</big><a class="reference internal" href="#PyFileObject" title="PyFileObject">PyFileObject</a><em> *p</em>, const char<em> *enc</em><big>)</big><a class="headerlink" href="#PyFile_SetEncoding" title="Permalink to this definition">¶</a></dt> <dd><p>Set the file’s encoding for Unicode output to <em>enc</em>. Return 1 on success and 0 on failure.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.3.</span></p> </dd></dl> <dl class="function"> <dt id="PyFile_SetEncodingAndErrors"> int <tt class="descname">PyFile_SetEncodingAndErrors</tt><big>(</big><a class="reference internal" href="#PyFileObject" title="PyFileObject">PyFileObject</a><em> *p</em>, const char<em> *enc</em>, *errors<big>)</big><a class="headerlink" href="#PyFile_SetEncodingAndErrors" title="Permalink to this definition">¶</a></dt> <dd><p>Set the file’s encoding for Unicode output to <em>enc</em>, and its error mode to <em>err</em>. Return 1 on success and 0 on failure.</p> <p class="versionadded"> <span class="versionmodified">New in version 2.6.</span></p> </dd></dl> <dl class="function"> <dt id="PyFile_SoftSpace"> int <tt class="descname">PyFile_SoftSpace</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em>, int<em> newflag</em><big>)</big><a class="headerlink" href="#PyFile_SoftSpace" title="Permalink to this definition">¶</a></dt> <dd><p id="index-5">This function exists for internal use by the interpreter. Set the <tt class="xref py py-attr docutils literal"><span class="pre">softspace</span></tt> attribute of <em>p</em> to <em>newflag</em> and return the previous value. <em>p</em> does not have to be a file object for this function to work properly; any object is supported (thought its only interesting if the <tt class="xref py py-attr docutils literal"><span class="pre">softspace</span></tt> attribute can be set). This function clears any errors, and will return <tt class="docutils literal"><span class="pre">0</span></tt> as the previous value if the attribute either does not exist or if there were errors in retrieving it. There is no way to detect errors from this function, but doing so should not be needed.</p> </dd></dl> <dl class="function"> <dt id="PyFile_WriteObject"> int <tt class="descname">PyFile_WriteObject</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *obj</em>, <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em>, int<em> flags</em><big>)</big><a class="headerlink" href="#PyFile_WriteObject" title="Permalink to this definition">¶</a></dt> <dd><p id="index-6">Write object <em>obj</em> to file object <em>p</em>. The only supported flag for <em>flags</em> is <tt class="xref py py-const docutils literal"><span class="pre">Py_PRINT_RAW</span></tt>; if given, the <a class="reference internal" href="../library/functions.html#str" title="str"><tt class="xref py py-func docutils literal"><span class="pre">str()</span></tt></a> of the object is written instead of the <a class="reference internal" href="../library/repr.html#module-repr" title="repr: Alternate repr() implementation with size limits."><tt class="xref py py-func docutils literal"><span class="pre">repr()</span></tt></a>. Return <tt class="docutils literal"><span class="pre">0</span></tt> on success or <tt class="docutils literal"><span class="pre">-1</span></tt> on failure; the appropriate exception will be set.</p> </dd></dl> <dl class="function"> <dt id="PyFile_WriteString"> int <tt class="descname">PyFile_WriteString</tt><big>(</big>const char<em> *s</em>, <a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em> *p</em><big>)</big><a class="headerlink" href="#PyFile_WriteString" title="Permalink to this definition">¶</a></dt> <dd><p>Write string <em>s</em> to file object <em>p</em>. Return <tt class="docutils literal"><span class="pre">0</span></tt> on success or <tt class="docutils literal"><span class="pre">-1</span></tt> on failure; the appropriate exception will be set.</p> </dd></dl> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h4>Previous topic</h4> <p class="topless"><a href="method.html" title="previous chapter">Method Objects</a></p> <h4>Next topic</h4> <p class="topless"><a href="module.html" title="next chapter">Module Objects</a></p> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li><a href="../_sources/c-api/file.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../search.html" method="get"> <input type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li class="right" > <a href="module.html" title="Module Objects" >next</a> |</li> <li class="right" > <a href="method.html" title="Method Objects" >previous</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="http://www.python.org/">Python</a> »</li> <li> <a href="../index.html">Python 2.7.5 documentation</a> » </li> <li><a href="index.html" >Python/C API Reference Manual</a> »</li> <li><a href="concrete.html" >Concrete Objects Layer</a> »</li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 1990-2020, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="http://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Oct 13, 2020. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3. </div> </body> </html>