curs_print(3X)

💖 curs_print(3X) — Library calls, but make it a group chat 💖

okay bestie, sit down, hydrate, because today we're talking about mcprint — the ncurses function that writes binary data to a printer using terminfo capabilities. yes. an actual printer. in the year of our lord. we love a retro moment 💅

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✨ NAME ✨

mcprint — write binary data to printer using terminfo capabilities 🖨️✨

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🌸 SYNOPSIS 🌸

#include <curses.h>

int mcprint(char * data, int len);

look at her. three lines. iconic. no cap. 🎀

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🦋 DESCRIPTION 🦋

so mcprint is an ncurses extension to the curses library, and what she does is she uses the terminal's prtr_non (mc5p) or prtr_on (mc5) and prtr_off (mc4) media copy capabilities — if they're defined, okay, only if — to send len bytes of the given string data to a printer attached to the terminal. literally sending your bytes to a printer. main character behaviour fr fr 💖

and now the part where I have to be a responsible bestie 😭 mcprint has no means of flow control to the printer, and no way of knowing how much buffering it has. none. zero. it's giving "sent it and hoped for the best."

so your application is responsible for keeping the rate of writes to the printer below its continuous throughput rate — typically about half of its nominal characters-per-second (cps) rating. that's the vibe check you have to do yourself, bestie, she will not do it for you 🙈

for reference: dot-matrix printers and 6-page-per-minute laser printers can typically handle 80 cps, so a conservative rule of thumb is to sleep for one second after sending an 80-character line. yes really. nap between lines. self-care 🫶

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💜 RETURN VALUE 💜

on success, mcprint returns the number of characters sent to the printer. slay. she tells you how much she ate 🔥

mcprint returns ERR if the write operation fails for any reason 😭 and in that event, errno contains either a value set by write(2), or one of the following:

• ENODEV — the terminal lacks relevant media copy capabilities. no printer energy detected. 💀
• ENOMEM — ncurses could not allocate sufficient memory to buffer the write operation. the memory said "not today". 😭

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🌈 EXTENSIONS 🌈

mcprint is an ncurses(3X) extension, and is not found in SVr4 curses, 4.4BSD curses, or any other previous curses implementation. she's new here. she's special. she's an original 💅✨

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🧚 PORTABILITY 🧚

applications employing this ncurses extension should condition its use on the visibility of the NCURSES_VERSION preprocessor macro. like, check first. don't just assume she's there. consent is key bestie 🎀

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⭐ HISTORY ⭐

ncurses introduced mcprint prior to version 1.9.9g (1996). she's been here since 1996 and she's still serving. legacy icon 👑

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💀 BUGS 💀

padding in the prtr_non (mc5p), prtr_on (mc5), and prtr_off (mc4) capabilities is not interpreted. just so you know. no padding for you. 🙈

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👑 SEE ALSO 👑

• curses(3X)

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and that's the whole page, bestie 🫶 this was pulled straight from ncurses 6.6, dated 2025-02-15, and the manual page itself is curs_print(3X). go forth and print responsibly. mwah 💖✨🎀