avr-g++ undefined reference to

Question

I am trying to write code for my atmega328 in C++ using Eclipse CDT. I have two projects. One project is static library project, that produces a static library. All the files in library are compiled without errors and library is created using the following command:

avr-ar -r  "libRobotMainBoard.a"  ./Console.o ./Motor.o ./RingBuffer.o ./io.o ./operators.o  

c:\Program Files\WINAVR\bin\avr-ar.exe: creating libRobotMainBoard.a

Then I use this library in other project that produces hex file for my atmega. But during the linking I get error:

C:\Users\Mitch\Disk Google\workspace\AVR\RobotMainBoard\Release\libRobotMainBoard.a(Console.o): In function Console::putCharToUDR()': Console.cpp:(.text._ZN7Console12putCharToUDREv+0x2): undefined reference to Console::txBuff'

and many othert similar to this. I have tried to find the solution on the web. Most of them mentions that this error is caused by naming library and the compiled file in the wrong order. I checked that and my order should be fine. I am linking it with the command:

avr-g++ -Wl,-Map,BoardTest.map,--cref -mrelax -Wl,--gc-sections -L"C:\Users\Mitch\Disk Google\workspace\AVR\RobotMainBoard\Release" -mmcu=atmega328p -o "BoardTest.elf" ./main.o -lRobotMainBoard

The main.cpp file looks like this:

#include <util/delay.h>
#include "Console.h"
#include "Motor.h"

Motor leftMotor(9,7);
Motor rightMotor(10,8);

int main(){
leftMotor.stop();
rightMotor.stop();

Console::setup(250000);

    while(1){
        Console::send('a');
        _delay_ms(2000);
    }
}

When I comment the Console lines out, it will link OK, even with Motor lines, which source files are in the same lib.

The Console cpp file is like this:

#include <avr/interrupt.h>
#include "Console.h"
#include "operators.h"

void Console::setup(uint16_t baudrate) {

    rxBuff = new RingBuffer(RX_BUFF_SIZE);
    txBuff = new RingBuffer(TX_BUFF_SIZE);

    uint16_t baudPrescaler= (F_CPU / (baudrate * 16)) - 1;

    UCSR0A = 0x00; UCSR0B = 0x00; UCSR0C = 0x00;
    //Using 8-bit, asynchronous, normal speed, 1 stop bit, no parity check

    UBRR0 = baudPrescaler;
    UCSR0C |= (1 << UCSZ01) | (1 << UCSZ00); //8-bit

    UCSR0B |= (1 << TXEN0) | (1 << RXEN0);
    sei();
}

void Console::send(char c) {
    txBuff->add(c);
    UCSR0B |= (1 << UDRIE0);
}

void Console::send(const char* s) {
    while(*s){
        send(*s++);
    }
}

void Console::putCharToUDR(){
    if(!txBuff->empty()){
        UDR0 = txBuff->remove();
    } else {
        UCSR0B &= ~(1 << UDRIE0);
    }
}

uint8_t Console::canReceive() {
    return rxBuff->available();
}

uint8_t Console::canTransmit() {
    return txBuff->available();
}

ISR(USART_RX_vect, ISR_BLOCK){

}

ISR(USART_UDRE_vect, ISR_BLOCK){
    Console::putCharToUDR();
}

Do anybody of you have any idea, why I am still getting the linking error?

EDIT 1

#ifndef CONSOLE_H_
#define CONSOLE_H_

#include "RingBuffer.h"

#define RX_BUFF_SIZE 32
#define TX_BUFF_SIZE 32

class Console {
public:
    static void setup(uint16_t baudrate);
    static void send(char c);
    static void send(const char* s);
    static uint8_t canReceive();
    static uint8_t canTransmit();
    static void putCharToUDR();
private:
    static RingBuffer *rxBuff;
    static RingBuffer *txBuff;

};

#endif /* CONSOLE_H_ */

Answer 1

As txBuff is static, you have to provide its definition in Console.cpp, e.g. RingBuffer * Console::txBuff = new RingBuffer(RX_BUFF_SIZE);