Arduino sketch, multiple definition error - c++

Question

I'm attempting to break out a previously working sketch I created into a class and sketch, and I'm having some trouble. I'm extending the functionality of a keyboard class designed for the board I'm working on, but the compiler keeps complaining about multiple definitions of functions.
here is my sketch, my .h, and my .cpp:
sketch
#include <DigiKeyboard.h>
#include "MacroKeyboard.h"
//constants
#define LED 1
#define SWITCH 0
//configuration
#define PAUSE_ON_ENTER true
const char command[] PROGMEM = "test string";
MacroKeyboard kb(command, SWITCH);
void setup() {
//tie switch to high
pinMode(SWITCH, OUTPUT);
digitalWrite(SWITCH, HIGH);
// set pins to correct uh whatever
pinMode(LED, OUTPUT);
pinMode(SWITCH, INPUT);
}
void loop() {
DigiKeyboard.update();
kb.update();
}
.h:
#ifndef MacroKeyboard_h
#define MacroKeyboard_h
#include "Arduino.h"
#define ON LOW
#define OFF HIGH
#define SCANCODE_DIFF 8
class MacroKeyboard {
const char* command;
int pin;
bool isPressed = false;
public:
MacroKeyboard(const char*, int);
void parseLetter(int);
void update();
};
#endif
.cpp:
#include <DigiKeyboard.h>
#include "MacroKeyboard.h"
MacroKeyboard::MacroKeyboard(const char* macro_position, int pin_number){
command = macro_position;
pin = pin_number;
}
void MacroKeyboard::parseLetter(int letter){
unsigned int scancode = pgm_read_byte_near(ascii_to_scan_code_table + letter - SCANCODE_DIFF);
unsigned int keycode = scancode & ((1 << 7) - 1); // masking off shift bit
unsigned int mods = 0;
unsigned int shift = (scancode & (1 << 7)) >> 7;
mods |= (shift == 1) ? MOD_SHIFT_LEFT : 0;
DigiKeyboard.sendKeyStroke(keycode, mods);
}
void MacroKeyboard::update(){
if(digitalRead(pin) == ON && !isPressed){
isPressed = true;
for (int i = 0; i < strlen(command); i++){
char letter = pgm_read_byte_near(command + i);
parseLetter(letter);
}
}
if (digitalRead(pin) == OFF && isPressed){
isPressed = false; // debounce
}
}
the errors I'm getting are this:
MacroKeyboard\MacroKeyboard.cpp.o: In function `usbFunctionSetup':
C:\Program Files (x86)\Digistump_Arduino\hardware\digistump\avr\libraries\DigisparkKeyboard/DigiKeyboard.h:216: multiple definition of `usbFunctionSetup'
MacroKeyboardTest.cpp.o:C:\Program Files (x86)\Digistump_Arduino\hardware\digistump\avr\libraries\DigisparkKeyboard/DigiKeyboard.h:216: first defined here
MacroKeyboard\MacroKeyboard.cpp.o: In function `MacroKeyboard::MacroKeyboard(char const*, int)':
C:\Program Files (x86)\Digistump_Arduino\hardware\digistump\avr\libraries\DigisparkKeyboard/DigiKeyboard.h:170: multiple definition of `DigiKeyboard'
MacroKeyboardTest.cpp.o:C:\Program Files (x86)\Digistump_Arduino\hardware\digistump\avr\libraries\DigisparkKeyboard/DigiKeyboard.h:199: first defined here
MacroKeyboard\MacroKeyboard.cpp.o:(.progmem.data.usbDescriptorHidReport+0x0): multiple definition of `usbDescriptorHidReport'
MacroKeyboardTest.cpp.o:(.progmem.data.usbDescriptorHidReport+0x0): first defined here
collect2: error: ld returned 1 exit status
Error compiling.
what am I doing wrong?

Answer 1

The library you use is written in a strange way. In the file DigiKeyboard.h there are such definitions as (comments mine):
// Declares a global variable.
// If you include this file in more than one cpp file it will cause linker error.
DigiKeyboardDevice DigiKeyboard = DigiKeyboardDevice();
// Defines a non-inline function
// Again, multiple definitions error if the file is included in several source files.
uchar usbFunctionSetup(uchar data[8]) {
// code
}
So you have to use it by including this .h file into only one of .cpp files.