>_ A TUI with zero curses: raw C and termios

terminal UI frameworks are a luxury and a lie. For tonarchy, the Arch installer-in-C, I wanted the fanciest-possible thing with no dependencies and no ncurses. What you discover: a TUI is just escape codes and a raw tty.

Getting the terminal to shut up

Terminals echo what you type. A TUI needs raw mode via termios:

#include <termios.h>
static struct termios oldtio;
tcgetattr(STDIN_FILENO, &oldtio);

struct termios raw = oldtio;
raw.c_lflag &= ~(ICANON | ECHO | ISIG);
raw.c_cc[VMIN] = 1;
raw.c_cc[VTIME] = 0;
tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);

Now one read() blocks per keystroke, with no newline buffet. Welcome to a game engine.

Drawing is printf with numbers

Screen drawing = cursor control + colors:

#define RESET  "\x1b[0m"
#define GREEN  "\x1b[32m"
#define HOME() printf("\x1b[H")

• \x1b[H — home cursor.
• \x1b[2K — clear line.
• Menus = a list of rows, one printf per row, redraw the whole thing.

The canvas discipline

No flicker hack, just: don’t draw before the screen clears. Render into a buffer, write() it once, flush. Reads on stdin, eats arrow keys from a 3-byte escape sequence.

What lessons came back

• Read the sequence, not the key: arrows arrive as ESC [ A, not A.
• tcsetattr restore in a signal handler if you don’t want a corpse terminal.
• Portability is a lie — Linux vs TERM shapes every escape you can trust.

if (seq_len == 3 && seq[0]==27 && seq[1]=='[' && seq[2]=='A')
    draw_arrow_up(); /* it's that simple and that fragile */

For the project this is pure joy. A C TUI with zero deps is the closest thing to a firmware you compile for your own terminal.