Why does servo library conflict with irremote?

Question

I am building an Arduino Mega robot. I am planning to use IRremote.h library for it. I am using multiple libraries in my code and I do not know which timers are taken. I always get errors when compiling because I am using the wrong timer. Here are the libraries I am using:

#include <LiquidCrystal.h>
#include <Wire.h>
#include <RTClib.h>
#include <Servo.h>
#include <IRremote.h>

I get this error message when compiling:

libraries\IRremote\IRremote.cpp.o: In function `__vector_42':

C:\Users\Lyuba\Desktop\Nick\Arduino\libraries\IRremote/IRremote.cpp:339: multiple definition of `__vector_42'

libraries\Servo\avr\Servo.cpp.o:C:\Users\Lyuba\Desktop\Nick\Arduino\libraries\Servo\src\avr/Servo.cpp:95: first defined here

c:/users/lyuba/desktop/nick/arduino/hardware/tools/avr/bin/../lib/gcc/avr/4.8.1/../../../../avr/bin/ld.exe: Disabling relaxation: it will not work with multiple definitions

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board Arduino/Genuino Mega or Mega 2560.

Here is the code in the library where I can change the timers:

// Arduino Mega
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  //#define IR_USE_TIMER1   // tx = pin 11
  //#define IR_USE_TIMER2     // tx = pin 9
 // #define IR_USE_TIMER3   // tx = pin 5
  #define IR_USE_TIMER4   // tx = pin 6
  //#define IR_USE_TIMER5   // tx = pin 46

What can I do to use irremote library? Looking at the error message, the servo library conflicts with irremote. How can I fix this?

Answer 1

Usual problem is trying to use the same counter for both. For example arduino pins 6,7,8 are on TC4 and if you try to use IR on pin 6 and servo on 7 or 8, it won't work. You can't use pwms on these pins with servo either (it is possible to do it directly in registers, but in arduino framework it might get bad behavior)