echo_char(9)

💅 echo_char(9) — Kernel API Manual 🎀

okay bestie, so we're in the kernel API manual and the star of the show is echo_char — literally the function that echoes a character back at you. yes, THAT girl. ✨

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🌸 NAME 🌸

echo_char — echo a character 🫶

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✨ SYNOPSIS ✨

void echo_char (u8 c , const struct tty_struct *tty );

like, that's the whole signature. short and iconic. 💅

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🎀 ARGUMENTS 🎀

• c — the unicode byte you wanna echo, bestie. one single byte. that's her whole job. 🦋
• tty — the terminal device, aka where all the vibes happen. const struct tty_struct * energy. 👑

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💖 DESCRIPTION 💖

okay so the whole point: this function echoes user input back onto the screen. you type, she shows it. main character behavior honestly. 😭

⚠️ big caveat bestie, do NOT skip this: this must be called only when L_ECHO(tty) is true. like, that's a hard requirement, no cap. and it's called from the tty_driver.receive_buf path. iykyk. 🔥

now the fun part — this variant tags control characters and echoes them as "^X" (where X is the letter representing the control char). so like a control char gets a lil glow-up with a caret in front. cute, readable, slay. ✨💀

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🦋 SEE ALSO 🦋

Kernel file ./drivers/tty/n_tty.c — and literally all her friends, the whole group chat:

• n_tty_kick_worker(9)
• n_tty_write_wakeup(9)
• put_tty_queue(9)
• reset_buffer_flags(9)
• n_tty_flush_buffer(9)
• is_utf8_continuation(9)
• is_continuation(9)
• do_output_char(9)
• process_output(9)
• process_output_block(9)
• __process_echoes(9)
• add_echo_byte(9)
• echo_move_back_col(9)
• echo_set_canon_col(9)
• echo_erase_tab(9)
• echo_char_raw(9)
• finish_erasing(9)
• eraser(9)
• isig(9)
• n_tty_receive_break(9)
• n_tty_receive_overrun(9)
• n_tty_receive_parity_error(9)
• n_tty_receive_char_flow_ctrl(9)
• n_tty_receive_char(9)
• n_tty_receive_buf_common(9)
• n_tty_set_termios(9)
• n_tty_close(9)
• n_tty_open(9)
• copy_from_read_buf(9)
• canon_copy_from_read_buf(9)
• job_control(9)
• n_tty_read(9)
• n_tty_write(9)
• n_tty_poll(9)
• n_tty_inherit_ops(9)

no cap, that's every single one. go read them all, bestie. 📚💜

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aaaand that's the page! 🎉 this whole manual situation comes to you from ./drivers/tty, dated October 2026, and it's filed under echo_char(9). mwah 💋✨ go echo some characters responsibly. 🧚💖