cannot declare variable to be of abstract type

Using Arduino Programming Questions
1

Hi , i am trying to use a custom msg to write a publisher for an arduino code which is as follows :

#include <Messenger.h>
#include <ros.h>
#include <std_msgs/String.h>
#include <SPI.h>
#include <rosserial_arduino/Acc_righthand.h>
#include <rosserial_arduino/Acc_left.h>

double data[7];
double data2[7];
double data3[7];
int i;
double x, y, z, a, b, c, p , q ,r ;
char separator = '\t';
ros::NodeHandle nh;
std_msgs::String str_msg, X_msg, Y_msg, Z_msg;
rosserial_arduino::Acc_righthand Acc_righthand_msg;
rosserial_arduino::Acc_left Acc_left_msg;
ros::Publisher pub_Acc_righthand("Acc_righthand", &Acc_righthand_msg);
ros::Publisher pub_Acc_left("Acc_left", &Acc_left_msg);

Messenger message1 = Messenger(separator); 
Messenger message2 = Messenger(separator);
Messenger message3 = Messenger(separator); 

void message1Ready() 
{                                 
  if ( message1.available() ) 
  {

    for(i=1;i<5;i++)
    {
      data[i] = message1.readDouble();  
    }
      x = data[1];
      y = data[2];
      z = data[3];
     
      Serial.print("Sensor1");
      Serial.print("\t");
      Serial.print(x);
      Serial.print("\t");
      Serial.print(y);
      Serial.print("\t");
      Serial.println(z);
      
        Acc_righthand_msg.x = x;
        Acc_righthand_msg.y = y;
        Acc_righthand_msg.z = z;
        pub_Acc_righthand.publish(&Acc_righthand_msg);
        nh.spinOnce();
      //delay(50);

  }       
}
void message2Ready() 
{                                 
  if ( message2.available() ) 
  {

    for(i=1;i<4;i++)
    {
      data2[i] = message2.readDouble();
    }
      
      a = data2[1];
      b = data2[2];
      c = data2[3];
      
      Serial.print("Sensor2");
      Serial.print("\t");
      Serial.print(a);
      Serial.print("\t");
      Serial.print(b);
      Serial.print("\t");
      Serial.println(c);
      
        Acc_left_msg.a = a;
        Acc_left_msg.b = b;
        Acc_left_msg.c = c;
        pub_Acc_left.publish(&Acc_left_msg);
        nh.spinOnce();
      

  } 
//delay(50);  
}
void message3Ready() 
{                                 
  if ( message3.available() ) 
  {

    for(i=1;i<5;i++)
    {
      data[i] = message3.readDouble();  
    }
      p = data[1];
      q = data[2];
      r = data[3];
     
      Serial.print("Sensor1");
      Serial.print("\t");
      Serial.print(p);
      Serial.print("\t");
      Serial.print(q);
      Serial.print("\t");
      Serial.println(r);
      
        Acc_righthand_msg.p = p;
        Acc_righthand_msg.q = q;
        Acc_righthand_msg.r = r;
        pub_Acc_righthand.publish(&Acc_righthand_msg);
        nh.spinOnce();
      //delay(50);

  }       
}

void setup() 
{ nh.initNode();
  nh.advertise(pub_Acc_righthand);
  nh.advertise(pub_Acc_left);
  // Initiate Serial Communication
  Serial.begin(57600); 
  Serial1.begin(57600);
  Serial2.begin(57600); 
  Serial3.begin(57600);

  // Attach the callback function to the Messenger
  message1.attach(message1Ready);
  message2.attach(message2Ready);
  message3.attach(message3Ready);

}
void loop() 
{
  // The following line is the most effective way of using Serial and Messenger's callback
  while ( Serial1.available() )
  { 
    message1.process(Serial1.read());
   }
   while ( Serial2.available() )
   {
     message2.process(Serial2.read());
   }
    while ( Serial3.available() )
  { 
    message3.process(Serial3.read());
   }
  

}

and i get the following error :

Acc_Recieverhand:15: error: cannot declare variable ‘Acc_righthand_msg’ to be of abstract type ‘rosserial_arduino::Acc_righthand’
/home/sp/arduino-1.0.1/libraries/ros_lib/rosserial_arduino/Acc_righthand.h:13: note: because the following virtual functions are pure within ‘rosserial_arduino::Acc_righthand’:
/home/sp/arduino-1.0.1/libraries/ros_lib/ros/msg.h:44: note: virtual int ros::Msg::serialize(unsigned char*) const
/home/sp/arduino-1.0.1/libraries/ros_lib/ros/msg.h:47: note: virtual const char* ros::Msg::getMD5()

Can anyone tell me what I am missing out on? I am still a beginner in arduino programming and I appreciate your help. Thanks in advance.

Regards,
Steve

2

Can anyone tell me what I am missing out on?

Sure can.

#include <rosserial_arduino/Acc_righthand.h>
#include <rosserial_arduino/Acc_left.h>

You are missing links to these libraries.

i am trying to use a custom msg to write a publisher

just doesn't go with

I am still a beginner

3

The message is kind of clear.

rosserial_arduino::Acc_righthand Acc_righthand_msg;

Acc_Recieverhand:15: error: cannot declare variable ‘Acc_righthand_msg’ to be of abstract type ‘rosserial_arduino::Acc_righthand’
/home/sp/arduino-1.0.1/libraries/ros_lib/rosserial_arduino/Acc_righthand.h:13: note: because the following virtual functions are pure within ‘rosserial_arduino::Acc_righthand’:

You have a function with '=0' after it ( or an error in your class that looks like one ). Using a class with pure virtual functions is a clear indication of error, as only a derived type will provide an implementation for the pure members. ( i.e a class with pure virtual functions can also be described as 'incomplete' or... abstract ).

It thinks you have these members marked as pure, do you?:

virtual int ros::Msg::serialize(unsigned char*) const
virtual const char* ros::Msg::getMD5()