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<H2><A NAME="SECTION009510000000000000000"></A><A NAME="fileObjects"></A>
<BR>
7.5.1 File Objects
</H2>
<P>
<a id='l2h-630' xml:id='l2h-630'></a>Python's built-in file objects are implemented entirely on the
<tt class="ctype">FILE*</tt> support from the C standard library. This is an
implementation detail and may change in future releases of Python.
<P>
<dl><dt><b><tt class="ctype"><a id='l2h-631' xml:id='l2h-631'>PyFileObject</a></tt></b></dt>
<dd>
This subtype of <tt class="ctype">PyObject</tt> represents a Python file object.
</dl>
<P>
<dl><dt>PyTypeObject <b><tt id='l2h-632' xml:id='l2h-632' class="cdata">PyFile_Type</tt></b></dt>
<dd>
This instance of <tt class="ctype">PyTypeObject</tt> represents the Python file
type. This is exposed to Python programs as <code>types.FileType</code>.
<a id='l2h-634' xml:id='l2h-634'></a></dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int <b><tt id='l2h-635' xml:id='l2h-635' class="cfunction">PyFile_Check</tt></b>(</nobr></td><td>PyObject *<var>p</var>)</td></tr></table></dt>
<dd>
Return true if its argument is a <tt class="ctype">PyFileObject</tt> or a subtype
of <tt class="ctype">PyFileObject</tt>.
<span class="versionnote">Changed in version 2.2:
Allowed subtypes to be accepted.</span>
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int <b><tt id='l2h-636' xml:id='l2h-636' class="cfunction">PyFile_CheckExact</tt></b>(</nobr></td><td>PyObject *<var>p</var>)</td></tr></table></dt>
<dd>
Return true if its argument is a <tt class="ctype">PyFileObject</tt>, but not a
subtype of <tt class="ctype">PyFileObject</tt>.
<span class="versionnote">New in version 2.2.</span>
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject* <b><tt id='l2h-637' xml:id='l2h-637' class="cfunction">PyFile_FromString</tt></b>(</nobr></td><td>char *<var>filename</var>, char *<var>mode</var>)</td></tr></table></dt>
<dd>
<div class="refcount-info">
<span class="label">Return value:</span>
<span class="value">New reference.</span>
</div>
On success, return a new file object that is opened on the file
given by <var>filename</var>, with a file mode given by <var>mode</var>, where
<var>mode</var> has the same semantics as the standard C routine
<tt class="cfunction">fopen()</tt><a id='l2h-651' xml:id='l2h-651'></a>. On failure, return <tt class="constant">NULL</tt>.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject* <b><tt id='l2h-638' xml:id='l2h-638' class="cfunction">PyFile_FromFile</tt></b>(</nobr></td><td>FILE *<var>fp</var>,
char *<var>name</var>, char *<var>mode</var>,
int (*close)(FILE*))</td></tr></table></dt>
<dd>
<div class="refcount-info">
<span class="label">Return value:</span>
<span class="value">New reference.</span>
</div>
Create a new <tt class="ctype">PyFileObject</tt> from the already-open standard C
file pointer, <var>fp</var>. The function <var>close</var> will be called
when the file should be closed. Return <tt class="constant">NULL</tt> on failure.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>FILE* <b><tt id='l2h-639' xml:id='l2h-639' class="cfunction">PyFile_AsFile</tt></b>(</nobr></td><td>PyFileObject *<var>p</var>)</td></tr></table></dt>
<dd>
Return the file object associated with <var>p</var> as a <tt class="ctype">FILE*</tt>.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject* <b><tt id='l2h-640' xml:id='l2h-640' class="cfunction">PyFile_GetLine</tt></b>(</nobr></td><td>PyObject *<var>p</var>, int <var>n</var>)</td></tr></table></dt>
<dd>
<div class="refcount-info">
<span class="label">Return value:</span>
<span class="value">New reference.</span>
</div>
Equivalent to <code><var>p</var>.readline(<big>[</big><var>n</var><big>]</big>)</code>, this
function reads one line from the object <var>p</var>. <var>p</var> may be a
file object or any object with a <tt class="method">readline()</tt> method. If
<var>n</var> is <code>0</code>, exactly one line is read, regardless of the
length of the line. If <var>n</var> is greater than <code>0</code>, no more
than <var>n</var> 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 <var>n</var> is less than <code>0</code>,
however, one line is read regardless of length, but
<tt class="exception">EOFError</tt> is raised if the end of the file is reached
immediately.
<a id='l2h-642' xml:id='l2h-642'></a></dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject* <b><tt id='l2h-643' xml:id='l2h-643' class="cfunction">PyFile_Name</tt></b>(</nobr></td><td>PyObject *<var>p</var>)</td></tr></table></dt>
<dd>
<div class="refcount-info">
<span class="label">Return value:</span>
<span class="value">Borrowed reference.</span>
</div>
Return the name of the file specified by <var>p</var> as a string
object.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>void <b><tt id='l2h-644' xml:id='l2h-644' class="cfunction">PyFile_SetBufSize</tt></b>(</nobr></td><td>PyFileObject *<var>p</var>, int <var>n</var>)</td></tr></table></dt>
<dd>
Available on systems with <tt class="cfunction">setvbuf()</tt><a id='l2h-652' xml:id='l2h-652'></a>
only. This should only be called immediately after file object
creation.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int <b><tt id='l2h-645' xml:id='l2h-645' class="cfunction">PyFile_Encoding</tt></b>(</nobr></td><td>PyFileObject *<var>p</var>, char *<var>enc</var>)</td></tr></table></dt>
<dd>
Set the file's encoding for Unicode output to <var>enc</var>. Return
1 on success and 0 on failure.
<span class="versionnote">New in version 2.3.</span>
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int <b><tt id='l2h-646' xml:id='l2h-646' class="cfunction">PyFile_SoftSpace</tt></b>(</nobr></td><td>PyObject *<var>p</var>, int <var>newflag</var>)</td></tr></table></dt>
<dd>
This function exists for internal use by the interpreter. Set the
<tt class="member">softspace</tt> attribute of <var>p</var> to <var>newflag</var> and
<a id='l2h-648' xml:id='l2h-648'></a>return the
previous value. <var>p</var> 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="member">softspace</tt> attribute can be set). This
function clears any errors, and will return <code>0</code> 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.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int <b><tt id='l2h-649' xml:id='l2h-649' class="cfunction">PyFile_WriteObject</tt></b>(</nobr></td><td>PyObject *<var>obj</var>, PyFileObject *<var>p</var>,
int <var>flags</var>)</td></tr></table></dt>
<dd>
Write object <var>obj</var> to file object <var>p</var>. The only supported
flag for <var>flags</var> is
<tt class="constant">Py_PRINT_RAW</tt><a id='l2h-653' xml:id='l2h-653'></a>; if given, the
<tt class="function">str()</tt> of the object is written instead of the
<tt class="function">repr()</tt>. Return <code>0</code> on success or <code>-1</code> on
failure; the appropriate exception will be set.
</dd></dl>
<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int <b><tt id='l2h-650' xml:id='l2h-650' class="cfunction">PyFile_WriteString</tt></b>(</nobr></td><td>const char *<var>s</var>, PyFileObject *<var>p</var>)</td></tr></table></dt>
<dd>
Write string <var>s</var> to file object <var>p</var>. Return <code>0</code> on
success or <code>-1</code> on failure; the appropriate exception will be
set.
</dd></dl>
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<span class="release-info">Release 2.4.3, documentation updated on 29 March 2006.</span>
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