legacy_coding(3X)

💖 legacy_coding — the ncurses library calls, bestie edition 💖

okay so real talk, this page lives in the ncurses library calls section, and it's all about use_legacy_coding. she's a little extension, she's a little niche, and she is SO fun once you get her. let's go ✨

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🌸 NAME 🌸

use_legacy_coding — override curses locale encoding checks

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🎀 SYNOPSIS 🎀

#include <curses.h>

int use_legacy_coding(int level);

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✨ DESCRIPTION ✨

so use_legacy_coding is an ncurses extension to the curses library (yes, an extension, we'll get to that in a sec 💅). what she does is let you customize the behavior of unctrl(3X), by suppressing isprint(3)-based checks inside the library — the ones that would normally make nonprinting characters get rendered in visible form.

important vibe check tho: this alteration only affects byte-wide characters with the most significant bit set. that's the whole scope. no cap.

the level parameter is what controls the result, and she's got three moods:

• 0 — the library functions normally, rendering nonprinting characters as described in unctrl(3X).
• 1 — the library ignores isprint for codes in the range 160-255.
• 2 — the library ignores isprint for codes in the range 128-255. it also modifies the output of unctrl(3X), showing codes in the range 128-159 as is.

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🫶 RETURN VALUE 🫶

if the curses screen has not been initialized, or if the level parameter is out of range, use_legacy_coding returns ERR. 😭

otherwise? she returns the previous level. cute, right? she's a gossip, she tells you what came before.

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🌈 EXTENSIONS 🌈

use_legacy_coding is an ncurses extension. that's it, that's the note. she's not standard-library-core, she's ncurses-exclusive main character energy 👑

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🦋 PORTABILITY 🦋

apps that employ ncurses extensions should condition their use on the visibility of the NCURSES_VERSION preprocessor macro.

like. if you're gonna use her, check that she's even invited to the party first. fr fr.

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💜 HISTORY 💜

ncurses 5.6 (2006) introduced use_legacy_coding to support lynx(1)'s font-switching feature. iconic origin story honestly, she was built for a browser 🧚

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⭐ AUTHORS ⭐

Thomas Dickey

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🔥 SEE ALSO 🔥

• unctrl(3X)

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and that's the whole page, babe 💅 this one shipped in ncurses 6.6, dated 2024-09-14 — go forth and encode responsibly 🎀✨