Skip to content

[3.7] bpo-30410: Documentation of sys.stdin/out/err update to reflect change in 3.6 (GH-10264) #11860

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
miss-islington merged 1 commit into from
Feb 14, 2019
Merged

[3.7] bpo-30410: Documentation of sys.stdin/out/err update to reflect change in 3.6 (GH-10264) #11860

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 24 additions & 7 deletions Doc/library/sys.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1348,13 +1348,30 @@ always available.
returned by the :func:`open` function. Their parameters are chosen as
follows:

* The character encoding is platform-dependent. Under Windows, if the stream
is interactive (that is, if its :meth:`isatty` method returns ``True``), the
console codepage is used, otherwise the ANSI code page. Under other
platforms, the locale encoding is used (see :meth:`locale.getpreferredencoding`).

Under all platforms though, you can override this value by setting the
:envvar:`PYTHONIOENCODING` environment variable before starting Python.
* The character encoding is platform-dependent. Non-Windows
platforms use the locale encoding (see
:meth:`locale.getpreferredencoding()`).

On Windows, UTF-8 is used for the console device. Non-character
devices such as disk files and pipes use the system locale
encoding (i.e. the ANSI codepage). Non-console character
devices such as NUL (i.e. where isatty() returns True) use the
value of the console input and output codepages at startup,
respectively for stdin and stdout/stderr. This defaults to the
system locale encoding if the process is not initially attached
to a console.

The special behaviour of the console can be overridden
by setting the environment variable PYTHONLEGACYWINDOWSSTDIO
before starting Python. In that case, the console codepages are
used as for any other character device.

Under all platforms, you can override the character encoding by
setting the :envvar:`PYTHONIOENCODING` environment variable before
starting Python or by using the new :option:`-X` ``utf8`` command
line option and :envvar:`PYTHONUTF8` environment variable. However,
for the Windows console, this only applies when
:envvar:`PYTHONLEGACYWINDOWSSTDIO` is also set.

* When interactive, ``stdout`` and ``stderr`` streams are line-buffered.
Otherwise, they are block-buffered like regular text files. You can
Expand Down