7.5.1 File Objects
Keywords: api

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7.5.1 File Objects

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 `types.FileType`.

int `PyFile_Check` (PyObject *p)
  Returns true if its argument is a `PyFileObject`.

PyObject* `PyFile_FromString` (char *filename, char *mode)
  Return value: New reference.
  On success, returns 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, returns `NULL`.

PyObject* `PyFile_FromFile` (FILE *fp, char *name, char *mode, int (*close)(FILE*))
  Return value: New reference.
  Creates a new `PyFileObject` from the already-open standard C file pointer, fp. The function close will be called when the file should be closed. Returns `NULL` on failure.

FILE* `PyFile_AsFile` (PyFileObject *p)
  Returns the file object associated with p as a `FILE*`.

PyObject* `PyFile_GetLine` (PyObject *p, int n)
  Return value: New reference.
  Equivalent to `p.readline([n])`, this function reads one line from the object p. p may be a file object or any object with a `readline()` method. If n is `0`, exactly one line is read, regardless of the length of the line. If n is greater than `0`, no more than n 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 n is less than `0`, however, one line is read regardless of length, but `EOFError` is raised if the end of the file is reached immediately.

PyObject* `PyFile_Name` (PyObject *p)
  Return value: Borrowed reference.
  Returns 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_SoftSpace` (PyObject *p, int newflag)
  This function exists for internal use by the interpreter. Sets the `softspace` attribute of p to newflag and returns 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, PyFileObject *p, int flags)
  Writes object obj to file object p. The only supported flag for flags is `Py_PRINT_RAW`; if given, the `str()` of the object is written instead of the `repr()`. Returns `0` on success or `-1` on failure; the appropriate exception will be set.

int `PyFile_WriteString` (char *s, PyFileObject *p, int flags)
  Writes string s to file object p. Returns `0` on success or `-1` on failure; the appropriate exception will be set.