Commit cfad5434 authored by Martin Panter's avatar Martin Panter

Issue #22413: Document newline effect on StringIO initializer and getvalue

Also add to comment in the C code.
parent e44dba3b
......@@ -864,10 +864,16 @@ Text I/O
An in-memory stream for text I/O. The text buffer is discarded when the
:meth:`~IOBase.close` method is called.
The initial value of the buffer (an empty string by default) can be set by
providing *initial_value*. The *newline* argument works like that of
:class:`TextIOWrapper`. The default is to consider only ``\n`` characters
as end of lines and to do no newline translation.
The initial value of the buffer can be set by providing *initial_value*.
If newline translation is enabled, newlines will be encoded as if by
:meth:`~TextIOBase.write`. The stream is positioned at the start of
the buffer.
The *newline* argument works like that of :class:`TextIOWrapper`.
The default is to consider only ``\n`` characters as ends of lines and
to do no newline translation. If *newline* is set to ``None``,
newlines are written as ``\n`` on all platforms, but universal
newline decoding is still performed when reading.
:class:`StringIO` provides this method in addition to those from
:class:`TextIOBase` and its parents:
......@@ -875,6 +881,8 @@ Text I/O
.. method:: getvalue()
Return a ``str`` containing the entire contents of the buffer.
Newlines are decoded as if by :meth:`~TextIOBase.read`, although
the stream position is not changed.
Example usage::
......
......@@ -52,7 +52,12 @@ extern PyObject *_PyIncrementalNewlineDecoder_decode(
which can be safely put aside until another search.
NOTE: for performance reasons, `end` must point to a NUL character ('\0').
Otherwise, the function will scan further and return garbage. */
Otherwise, the function will scan further and return garbage.
There are three modes, in order of priority:
* translated: Only find \n (assume newlines already translated)
* universal: Use universal newlines algorithm
* Otherwise, the line ending is specified by readnl, a str object */
extern Py_ssize_t _PyIO_find_line_ending(
int translated, int universal, PyObject *readnl,
int kind, char *start, char *end, Py_ssize_t *consumed);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment