Description

fedonman

opened on Aug 25, 2026

Issue body actions

Documentation

The curses HOWTO says that strings passed to window.addstr() are "encoded to bytes using the value of the window's encoding attribute", and the window.encoding entry in the library reference describes it as the "Encoding used to encode method arguments (Unicode strings and characters)". On a build linked against a wide-character version of the curses library, which is what CPython configures by default, neither is true: PyCurses_ConvertToString in Modules/_cursesmodule.c converts str with PyUnicode_AsWideCharString and never reads win->encoding, so the bytes that reach the terminal come from the current locale instead.

import curses, os, pty, sys
_, slave = pty.openpty()
os.dup2(slave, 0); os.dup2(slave, 1)
win = curses.initscr()
win.encoding = 'latin-1'
win.addstr(0, 0, 'caf\xe9')
got = win.instr(0, 0, 6)
curses.endwin()
print('stored:', got, '  latin-1 would be:', 'caf\xe9'.encode('latin-1'), file=sys.stderr)

stored: b'caf\xc3\xa9 '   latin-1 would be: b'caf\xe9'

Expected: b'caf\xe9', the bytes latin-1 produces, if window.encoding were used to encode the argument.

The attribute is used on a narrow build, where it also decodes results, so the correction has to name the build rather than call the attribute unused.

Linked PRs

• gh-156347: Fix the documentation of curses window.encoding #156352
• gh-156347: Fix wrong statements in the curses documentation #156354
• [3.15] gh-156347: Fix wrong statements in the curses documentation (GH-156354) #156872
• [3.14] gh-156347: Fix wrong statements in the curses documentation (GH-156354) #156873
• [3.13] gh-156347: Fix wrong statements in the curses documentation (GH-156354) #156874

Activity

1. serhiy-storchaka

   self-assigned this

   on Aug 25, 2026
2. serhiy-storchaka

   added

   docsDocumentation in the Doc dirDocumentation in the Doc dir

   topic-curses

   on Aug 25, 2026
3. github-project-automation

   added this to docs issueson Aug 25, 2026
4. github-project-automation

   moved this to Todo in docs issueson Aug 25, 2026
5. serhiy-storchaka

   added this to Curses issueson Aug 25, 2026
6. serhiy-storchaka commented on Aug 25, 2026

   

   serhiy-storchaka

   on Aug 25, 2026

   Member

   More actions

   There are many other wrong statements in the curses HOWTO. #156354 fixes them and slightly modernizes the documentation.
7. fedonman commented on Aug 25, 2026

   

   fedonman

   on Aug 25, 2026

   ContributorAuthor

   More actions

   @serhiy-storchaka I had already opened #156352 Should I close it?
8. serhiy-storchaka commented on Aug 27, 2026

   

   serhiy-storchaka

   on Aug 27, 2026

   Member

   More actions

   Yes, I think it is superseded by #156354.
9. serhiy-storchaka

   added 3 commits that reference this issue on Sep 3, 2026

   gh-156347: Fix wrong statements in the curses documentation (GH-156354)

   161054c

   [3.14] gh-156347: Fix wrong statements in the curses documentation (G…

   a3084ff

   [3.13] gh-156347: Fix wrong statements in the curses documentation (G…

   6ad0c73
10. serhiy-storchaka

    closed this as completedon Sep 3, 2026
11. github-project-automation

    moved this to Done in Curses issueson Sep 3, 2026
12. hugovk

    added a commit that references this issue on Sep 5, 2026

    [3.15] gh-156347: Fix wrong statements in the curses documentation (G…

    996300c
13. clin1234

    added a commit that references this issue on Sep 12, 2026

    pythongh-156347: Fix wrong statements in the curses documentation (py…

    a81d06a

Issue actions