qmk-firmware/keyboard/atreus/atreus.h

#ifndef ATREUS_H
#define ATREUS_H

#include "matrix.h"
#include "keymap.h"
#include "backlight.h"
#include <stddef.h>

// This a shortcut to help you visually see your layout.
// The first section contains all of the arguements
// The second converts the arguments into a two-dimensional array
#define KEYMAP( \
  k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, \
  k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, \
  k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, \
  k30, k31, k32, k33, k34, k35, k36, k37, k38, k39, k3a \
) \
{ \
	{ k00, k01, k02, k03, k04, KC_NO, k05, k06, k07, k08, k09 }, \
	{ k10, k11, k12, k13, k14, KC_NO, k15, k16, k17, k18, k19 }, \
	{ k20, k21, k22, k23, k24, k35,   k25, k26, k27, k28, k29 }, \
	{ k2a, k30, k31, k32, k33, k34,   k36, k37, k38, k39, k3a } \
}

void matrix_init_user(void);
void matrix_scan_user(void);

#endif