gh-154139: Document that curses is not thread-safe#154173
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gh-154139: Document that curses is not thread-safe#154173serhiy-storchaka wants to merge 1 commit into
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Whether curses is thread-safe depends on the library and how it was built. The blocking and refresh methods release the GIL, so with a non-reentrant curses, unsynchronized use from several threads can crash. Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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Documents the thread-safety limitation reported in #154139.
_cursesreleases the GIL around the blocking and refresh calls (getch,refresh, …), so with a non-reentrant curses — the default ncurses build on many systems — two threads can race on the shared global screen state and crash the interpreter. Whether curses is usable from multiple threads depends on the library and how it was built, so this is a documentation gap rather than a missing lock in CPython.The note points to serializing the calls or wrapping them in
window.use()/screen.use(), which lock only when the library is built with reentrant support.