Compilation error when creating ISR(vect) interruption : multiple definition of `TIMER0_COMPA_vect'

Question

Good morning everyone i'm posting this here because i can't figure it out on my own. I've been trying to add ISR function in my project but it doesn't compile.

I work on Microship studio on an ATmega328p on a raw c++ project (NO ARDUINO).

I've been trying to add ISR(vect) interruption in my program but i can't manage to compile and i don't anderstand what i'm doing wrong.

In my code i'm using TIMER0_COMPA_vect but it also doesn't work with none of the 25 vectors in iom328p.h nor with _VECTOR(14).

Here's my code :

#include <avr/interrupt.h>
#include <avr/io.h>

#define F_CPU 9999999

static unsigned long long tick = 0;

static void startup(){
    TCCR0B = 0x01; // set Prescaller
    OCR0A = 200;   //Set the flag trig at 200
    TIMSK0 = (1<<OCIE0A); //interrupt 
}

ISR(TIMER0_COMPA_vect){
    ;
}

Here is the error :

Error       ld returned 1 exit status
Error       multiple definition of `TIMER0_COMPA_vect'  config.h    23
Error       recipe for target 'project.elf' failed

score 2 · Answer 1 · answered Jun 12 '22 at 15:11

[I'm assuming that config.h is the name of the file you quoted in the question.]

If you've put the definition in a header file that's included in multiple compilation units, then the linker is noticing that it's been defined multiple times. It's a violation of the one-definition rule in C++.

You can declare the ISR in a header file, but the definition should be in an implementation file (.cpp, .cc, .c, etc.).
If you don't need to declare it in the header file, then just move the entire function to an implementation file.
If you must define it in a header file, then you can add inline to the function signature, which is a misleadingly named way around the one-definition rule.

Compilation error when creating ISR(vect) interruption : multiple definition of `TIMER0_COMPA_vect'

1 Answers1