qmk_firmware/users/mtei/pseudo_sprintf.h

// Copyright 2022 Takeshi Ishii (@mtei)
// SPDX-License-Identifier: GPL-2.0-or-later

#pragma once

char *sprints(char *buf, char *src);
char *sprintd(char *buf, char *leadstr, int data);
char *sprint2d(char *buf, char *leadstr, int data);