多定义错误-- Arduino库

Question

我正在为Arduino建造一个基本的汽车图书馆。我正在尝试用草图motordrivertest.ino测试它，并且我不断地得到我的整个电机类及其所有方法的多个定义错误。我想知道怎样才能纠正这些错误。(我使用的是MAC OS X 10.9.3)

这是我的错误。

MotorDriver/motordriver.cpp.o: In function `Motor::getSpeed()':
/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:49: multiple definition of `Motor::getSpeed()'
motordrivertest.cpp.o:/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:49: first defined here
MotorDriver/motordriver.cpp.o: In function `Motor::setSpeed(int)':
/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:33: multiple definition of `Motor::setSpeed(int)'
motordrivertest.cpp.o:/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:33: first defined here
MotorDriver/motordriver.cpp.o: In function `Motor':
/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:15: multiple definition of `Motor::Motor(char)'
motordrivertest.cpp.o:/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:15: first defined here
MotorDriver/motordriver.cpp.o: In function `Motor':
/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:15: multiple definition of `Motor::Motor(char)'
motordrivertest.cpp.o:/Users/pattyborgman/Documents/Arduino/libraries/MotorDriver/motordriver.cpp:15: first defined here

这是我的草图，.h文件和.cpp文件。

motordrivertest.ino

#include "motordriver.h"
#include "motordriver.cpp"

Motor motor('a');

void setup(){}

void loop()
{
 motor.setSpeed(125);
 delay(3000);
 motor.setSpeed(-125);
 delay(3000); 
}

motordriver.h

#ifndef motordriver_h
#define motordriver_h

#include "Arduino.h"

class Motor
{
public:
    Motor(char letter);
    void setSpeed(int speed);
    int getSpeed();
private:
    int currentSpeed;
    int PWM;
    int BRK;
    int DIR;

};

#endif

motordriver.cpp

#include "Arduino.h"
#include "motordriver.h"

Motor::Motor(char letter)
{
        if (letter=='a') {
            int PWM = 3;
            int BRK = 9;
            int DIR = 12;
            pinMode(PWM, OUTPUT);
            pinMode(BRK, OUTPUT);
            pinMode(DIR, OUTPUT);
        } else {
            int PWM = 11;
            int BRK = 8;
            int DIR = 13;
            pinMode(PWM, OUTPUT);
            pinMode(BRK, OUTPUT);
            pinMode(DIR, OUTPUT);
        }

}

void Motor::setSpeed(int speed)
{
    currentSpeed=speed;
    if (speed >= 0) {
        analogWrite(PWM, speed);
        digitalWrite(BRK, LOW);
        digitalWrite(DIR, HIGH);
    }else {
        int _speed = -speed;
        analogWrite(PWM, _speed);
        digitalWrite(BRK, LOW);
        digitalWrite(DIR, LOW);
    }

}

int Motor::getSpeed()
{
    return currentSpeed;
}

Answer 1

避免这类错误的简单规则：

• 永远不要包含.cpp文件
• 如果在头文件中实现函数或方法，请在它们前面写内联(不包括模板，默认情况下它们是内联的)。

C(++)-源代码编译成目标文件.对于每个.cpp文件，将生成一个对象文件。这些文件将包含函数/方法的机器代码。包含源文件将在多个对象文件中为您提供相同的函数。编译器没问题。编译器运行后，链接器将完成将所有对象文件和静态库组合到一个可执行文件的工作。现在，它找到了几个同名函数。那么它应该做什么呢？它会通知您它遇到的错误和退出。