tools/src/nas,5.n2.os.2/lib/python/html/python/api/fileObjects.html

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<H2><A NAME="SECTION009510000000000000000"></A><A NAME="fileObjects"></A>
<BR>
7.5.1 File Objects
</H2>

<P>
<a id='l2h-631' xml:id='l2h-631'></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-632' xml:id='l2h-632'>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-633' xml:id='l2h-633' 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-635' xml:id='l2h-635'></a></dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>int&nbsp;<b><tt id='l2h-636' xml:id='l2h-636' 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&nbsp;<b><tt id='l2h-637' xml:id='l2h-637' 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*&nbsp;<b><tt id='l2h-638' xml:id='l2h-638' 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-652' xml:id='l2h-652'></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*&nbsp;<b><tt id='l2h-639' xml:id='l2h-639' 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*&nbsp;<b><tt id='l2h-640' xml:id='l2h-640' 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*&nbsp;<b><tt id='l2h-641' xml:id='l2h-641' 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-643' xml:id='l2h-643'></a></dd></dl>

<P>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"><td><nobr>PyObject*&nbsp;<b><tt id='l2h-644' xml:id='l2h-644' 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&nbsp;<b><tt id='l2h-645' xml:id='l2h-645' 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-653' xml:id='l2h-653'></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&nbsp;<b><tt id='l2h-646' xml:id='l2h-646' 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&nbsp;<b><tt id='l2h-647' xml:id='l2h-647' 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-649' xml:id='l2h-649'></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&nbsp;<b><tt id='l2h-650' xml:id='l2h-650' 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-654' xml:id='l2h-654'></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&nbsp;<b><tt id='l2h-651' xml:id='l2h-651' 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>

<P>

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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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