tty_tiocmset(9)

💅 tty_tiocmset — set modem status ✨

okay so bestie, welcome to the Kernel API Manual page for tty_tiocmset(9) — yes it's a section 9 page, yes it's kernel-internal, no you cannot escape the tty subsystem, it's literally everywhere 💀

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✨ SYNOPSIS ✨

int tty_tiocmset (struct tty_struct *tty , unsigned int cmd , unsigned
__user *p );

that's the whole signature, no notes, she's serving "three-argument queen" and honestly? iconic.

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🎀 ARGUMENTS 🎀

• tty — the tty device, your main character, the whole point 🫶
• cmd — the command, and she's one of three vibes: clear bits, set bits, or set all — pick your fighter 💅
• p — a pointer to the bits you actually want, the user-space wish list, the blueprint 🌸

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🦋 DESCRIPTION 🦋

okay so here's the tea: tty_tiocmset sets the modem status bits, and it does that from the tty driver — but only if the driver's feature set actually supports it. not everyone can sit with us, y'know?

if the feature is not available, it returns -ENOTTY. that's it, that's the rejection text, no explanation, just -ENOTTY and a closed door 😭

Locking: none (up to the driver) — like, the function itself takes no locks, so if the driver needs locking, the driver sorts it out. no cap, that's the actual deal 🙈

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💜 SEE ALSO 💜

the lore is deep, so here's the full squad, straight from the kernel file ./drivers/tty/tty_io.c:

• free_tty_struct(9), tty_free_file(9), tty_name(9), get_tty_driver(9), tty_dev_name_to_number(9)
• tty_find_polling_driver(9), tty_wakeup(9), tty_release_redirect(9), __tty_hangup(9), tty_hangup(9)
• tty_vhangup(9), tty_vhangup_self(9), tty_vhangup_session(9), tty_hung_up_p(9), stop_tty(9)
• start_tty(9), tty_read(9), tty_write(9), tty_send_xchar(9), pty_line_name(9)
• tty_line_name(9), tty_driver_lookup_tty(9), tty_init_termios(9), tty_standard_install(9), tty_driver_install_tty(9)
• tty_driver_remove_tty(9), tty_reopen(9), tty_init_dev(9), tty_save_termios(9), tty_flush_works(9)
• release_one_tty(9), tty_kref_put(9), release_tty(9), tty_release_checks(9), tty_kclose(9)
• tty_release_struct(9), tty_release(9), tty_open_current_tty(9), tty_lookup_driver(9), tty_kopen_exclusive(9)
• tty_kopen_shared(9), tty_open_by_driver(9), tty_open(9), tty_poll(9), tiocsti(9)
• tiocgwinsz(9), tty_do_resize(9), tiocswinsz(9), tioccons(9), tiocsetd(9)
• tiocgetd(9), send_break(9), tty_get_tiocm(9), tty_tiocmget(9), tty_get_icount(9)
• alloc_tty_struct(9), tty_put_char(9), tty_register_device(9), tty_register_device_attr(9), tty_unregister_device(9)
• __tty_alloc_driver(9), tty_driver_kref_put(9), tty_register_driver(9), tty_unregister_driver(9)

that's sixty-something friends and every single one of them is a real cross-reference, i checked, i would never lie to you 💖

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and that's the page!! mwah 💋

cute little sign-off bestie: this one lives in ./drivers/tty and she was stamped October 2026 — go read the source, go be obsessed, go set some modem status bits, periodt 🎀👑