tty_mode_ioctl(9)

💅 tty_mode_ioctl(9) — the kernel API manual, bestie edition ✨

okay so real talk, this is tty_mode_ioctl from the Kernel API Manual, and it's lowkey one of those little functions that keeps the whole tty world from descending into chaos 🌀 grab a strawberry drink 🍓 and let's get into it.

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✨ NAME ✨

tty_mode_ioctl — the mode-related ioctls, aka the vibe-checker for terminal modes 🎀

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✨ SYNOPSIS ✨

int tty_mode_ioctl (struct tty_struct *tty , unsigned int cmd , unsigned
       long arg );

that's the whole signature, no cap 👑

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✨ ARGUMENTS ✨

• tty — the tty you're doing the ioctl on 🫶 like, the actual terminal device in question
• cmd — the command. yes. the command. the thing you're asking for 💅
• arg — the ioctl argument, carrying whatever extra info the command needs

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✨ DESCRIPTION ✨

so basically this bad boy performs the non-line discipline specific mode control ioctls 🔥 read that again: non-line-discipline-specific. it's the generic mode stuff, not the stuff that belongs to one particular line discipline.

and the whole point? it's designed to be called by line disciplines themselves — iconic behaviour tbh 👑 — so that they all provide consistent mode setting. like, everybody shows up wearing the same fit, no mismatched energy, no "wait why does this driver behave differently" moments 😭

it's giving group project where everyone actually coordinates. rare. beautiful. slay 💖

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🌈 SEE ALSO 🌈

kernel file ./drivers/tty/tty_ioctl.c — that's where the magic lives, go read it iykyk 📖✨

and the whole friend group of related calls:

• tty_chars_in_buffer(9)
• tty_write_room(9)
• tty_driver_flush_buffer(9)
• tty_unthrottle(9)
• tty_throttle_safe(9)
• tty_unthrottle_safe(9)
• tty_wait_until_sent(9)
• tty_termios_copy_hw(9)
• tty_termios_hw_change(9)
• tty_get_char_size(9)
• tty_get_frame_size(9)
• tty_set_termios(9)
• set_termios(9)
• set_sgttyb(9)
• tty_change_softcar(9)

like yes that's a lot of besties but they all ate 💅

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ok that's the whole page, no filler, no extra lore. everything above is literally everything the original says — i would never leave a detail behind 🫶

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and that's a wrap, bestie 🦋 this page lives in ./drivers/tty, it's stamped October 2026, and the page itself is literally called tty_mode_ioctl(9) — go forth and set those modes consistently, mwah 💜🎀