ファイルオブジェクト
********************

Python’s built-in file objects are implemented entirely on the "FILE*"
support from the C standard library.  This is an implementation detail
and may change in future releases of Python.

PyFileObject

   This subtype of "PyObject" represents a Python file object.

PyTypeObject PyFile_Type

   This instance of "PyTypeObject" represents the Python file type.
   This is exposed to Python programs as "file" and "types.FileType".

int PyFile_Check(PyObject *p)

   Return true if its argument is a "PyFileObject" or a subtype of
   "PyFileObject".

   バージョン 2.2 で変更: Allowed subtypes to be accepted.

int PyFile_CheckExact(PyObject *p)

   Return true if its argument is a "PyFileObject", but not a subtype
   of "PyFileObject".

   バージョン 2.2 で追加.

PyObject* PyFile_FromString(char *filename, char *mode)
    *Return value: New reference.*

   On success, return a new file object that is opened on the file
   given by *filename*, with a file mode given by *mode*, where *mode*
   has the same semantics as the standard C routine "fopen()".  On
   failure, return *NULL*.

PyObject* PyFile_FromFile(FILE *fp, char *name, char *mode, int (*close)(FILE*))
    *Return value: New reference.*

   Create a new "PyFileObject" from the already-open standard C file
   pointer, *fp*.  The function *close* will be called when the file
   should be closed.  Return *NULL* and close the file using *close*
   on failure. *close* is optional and can be set to *NULL*.

FILE* PyFile_AsFile(PyObject *p)

   Return the file object associated with *p* as a "FILE*".

   If the caller will ever use the returned "FILE*" object while the
   *GIL* is released it must also call the "PyFile_IncUseCount()" and
   "PyFile_DecUseCount()" functions described below as appropriate.

void PyFile_IncUseCount(PyFileObject *p)

   Increments the PyFileObject’s internal use count to indicate that
   the underlying "FILE*" is being used. This prevents Python from
   calling f_close() on it from another thread. Callers of this must
   call "PyFile_DecUseCount()" when they are finished with the
   "FILE*".  Otherwise the file object will never be closed by Python.

   The *GIL* must be held while calling this function.

   The suggested use is to call this after "PyFile_AsFile()" and
   before you release the GIL:

      FILE *fp = PyFile_AsFile(p);
      PyFile_IncUseCount(p);
      /* ... */
      Py_BEGIN_ALLOW_THREADS
      do_something(fp);
      Py_END_ALLOW_THREADS
      /* ... */
      PyFile_DecUseCount(p);

   バージョン 2.6 で追加.

void PyFile_DecUseCount(PyFileObject *p)

   Decrements the PyFileObject’s internal unlocked_count member to
   indicate that the caller is done with its own use of the "FILE*".
   This may only be called to undo a prior call to
   "PyFile_IncUseCount()".

   The *GIL* must be held while calling this function (see the example
   above).

   バージョン 2.6 で追加.

PyObject* PyFile_GetLine(PyObject *p, int n)
    *Return value: New reference.*

   "p.readline([n])" と同じで、この関数はオブジェクト *p* の各行を読み
   出します。 *p* はファイルオブジェクトか、 "readline()" メソッドを持
   つ何らかのオブジェクトでかまいません。 *n* が "0" の場合、行の長さ
   に関係なく正確に 1 行だけ読み出します。 *n* が "0" より大きければ、
   *n* バイト以上のデータは読み出しません; 従って、行の一部だけが返さ
   れる場合があります。 どちらの場合でも、読み出し後すぐにファイルの終
   端に到達した場合には空文字列を 返します。 *n* が "0" より小さければ
   、長さに関わらず 1 行だけを 読み出しますが、すぐにファイルの終端に
   到達した場合には "EOFError" を送出します。

PyObject* PyFile_Name(PyObject *p)
    *Return value: Borrowed reference.*

   Return the name of the file specified by *p* as a string object.

void PyFile_SetBufSize(PyFileObject *p, int n)

   Available on systems with "setvbuf()" only.  This should only be
   called immediately after file object creation.

int PyFile_SetEncoding(PyFileObject *p, const char *enc)

   Set the file’s encoding for Unicode output to *enc*. Return "1" on
   success and "0" on failure.

   バージョン 2.3 で追加.

int PyFile_SetEncodingAndErrors(PyFileObject *p, const char *enc, *errors)

   Set the file’s encoding for Unicode output to *enc*, and its error
   mode to *err*. Return "1" on success and "0" on failure.

   バージョン 2.6 で追加.

int PyFile_SoftSpace(PyObject *p, int newflag)

   This function exists for internal use by the interpreter.  Set the
   "softspace" attribute of *p* to *newflag* and return the previous
   value. *p* does not have to be a file object for this function to
   work properly; any object is supported (thought its only
   interesting if the "softspace" attribute can be set).  This
   function clears any errors, and will return "0" 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.

int PyFile_WriteObject(PyObject *obj, PyObject *p, int flags)

   オブジェクト *obj* をファイルオブジェクト *p* に書き込みます。
   *flags* がサポートするフラグは "Py_PRINT_RAW" だけです; このフラグ
   を指定すると、オブジェクトに "repr()" ではなく "str()" を適用した結
   果をファイルに書き出します。成功した場合には "0" を返し、失敗すると
   "-1" を返して適切な例外をセットします。

int PyFile_WriteString(const char *s, PyObject *p)

   文字列 *s* をファイルオブジェクト *p* に書き出します。成功した場合
   には "0" を返し、失敗すると "-1" を返して適切な例外をセットします。
