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# 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. The `PyFile_` APIs are a wrapper over the `io` module.

`PyFile_FromFd`(int fd, char *name, char *mode, int buffering, char *encoding, char *newline, int closefd)

  Create a new `PyFileObject` from the file descriptor of an already opened file fd. The arguments name, encoding and newline can be NULL to use the defaults; buffering can be -1 to use the default. Return NULL on failure.

  Warning

  Take care when you are mixing streams and descriptors! For more information, see the GNU C Library docs.

int `PyObject_AsFileDescriptor`(PyObject *p)
  Return the file descriptor associated with p as an `int`. If the object is an integer, its value is returned. If not, the object’s `fileno()` method is called if it exists; the method must return an integer, which is returned as the file descriptor value. Sets an exception and returns `-1` on failure.

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.

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

  Write 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()`. Return `0` on success or `-1` on failure; the appropriate exception will be set.

int `PyFile_WriteString`(const char *s, PyObject *p)
  Write string s to file object p. Return `0` on success or `-1` on failure; the appropriate exception will be set.

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