Problem with Class Constructor trying to emulate YUN Console.print

Getting Started
1

I am trying to port a Sketch I wrote for the Arduino using the YUN Shield. I used the Console.h and Console.print class in a lot of places for debugging. I thought I would create a class that wraps the Particle Publish but look like the Console class.

I am getting an error that I don’t understand which is:
" ISO C++ forbids the declaration of ‘Console’ with no type."

My Console.cpp looks like this:

#ifndef  Console_h
#define  Console_h
#define  EVENTNAME "Tracker 1"
#include <stdlib.h>
#include <Particle.h>

class PublishConsole {
   public:
      Console();
      void print(int i);
      void print(double  f);
      void print(char* c);
      void print(String* c);
      void println(int i);
      void println(long i);
      void println(double  f);
      void println(char* c);
      void print(unsigned long i);
};
#endif

#include <Console.h>

void PublishConsole::Console(void)
{}

void PublishConsole::print(int i) {
  char data[33];
  itoa(i,data,10);
  Particle.publish(EVENTNAME,data, 60, PRIVATE);
}

void PublishConsole::print(double  f) {
  String data = String(f);
  Particle.publish(EVENTNAME,data, 60, PRIVATE);
}

void PublishConsole::print(char* c) {
  Particle.publish(EVENTNAME,c, 60, PRIVATE);
}
void PublishConsole::print(String* c) {
  Particle.publish(EVENTNAME,c, 60, PRIVATE);
}
void PublishConsole::println(int i) {
  char data[33];
  itoa(i,data,10);
  Particle.publish(EVENTNAME,data, 60, PRIVATE);
}
void PublishConsole::println(long i) {
  char data[33];
  itoa(i,data,10);
  Particle.publish(EVENTNAME,data, 60, PRIVATE);
}
void PublishConsole::print(unsigned long i) {
  char data[33];
  itoa(i,data,10);
  Particle.publish(EVENTNAME,data, 60, PRIVATE);
}

void PublishConsole::println(double  f) {
  String data = String(f);
  Particle.publish(EVENTNAME,data, 60, PRIVATE);
}

void PublishConsole::println(char* c) {
  Particle.publish(EVENTNAME,c, 60, PRIVATE);
}
2

The implementation of your constructor should not have a type in front of it.

PublishConsole::Console() {}

The error you're getting is not the same one I get if I do what you did, but I think this is the problem. However, I think that you don't need the constructor at all since your implementation does nothing. In C++, a default constructor is provided automatically if you don't create any constructors yourself.

3

That is not even a constructor.
Constructors have to have the same name as the class, so it should be

  PublishConsole::PublishConsole() { }
1 Like
4

Oh duh! I guess that explains why I didn't get the same error when I tested (I put a void in front of a proper constructor).

5

Thanks that was helpful. I looked at a lot of example but nothing about that was mentioned.

What are the forms of Particle.publish? Now I am getting an error:

no matching function call to CloudPublish::publish(String&, String*&, int, const PublishFlag in the class function :

void PublishConsole::print(String* c) {
  Particle.publish(EventName,c, 60, PRIVATE);
}
6

The way you have it written, you should pass in a String object or a char* as the event data, but not a pointer to a String as you’re doing (a String*). You could pass in a pointer to a String to your PublishConsole::print function if you need to, but you would have to dereference that pointer in the Particle.publish statement (Particle.publish(EventName, *c, 60, PRIVATE))

7

@ispybadguys, do remember that Particle.publish()'s are limited to one per second. You can’t feed it at the same rate you would a console.

8

Thanks Ric.

I do sometimes make some basic C mistakes. I f you don’t mind I have one more C error I don’t understand.

I have the following code in a header called Externals.h.


typedef struct sunposition {float Declination; float Elevation; float Azimuth; float HourAngle;};
extern sunposition Sun;

And then in a file called SunLoacation.h

include <math.h>
#include <Externals.h>
#include <Defines.h>
#include <Particle.h>
#include <functionPrototypes.h>
#include <Console.h>


struct sunposition Sun;

I get this error:
redefinition of ‘struct sunposition’
…Externals.h 27:16
previous definition of ‘struct sunposition’
…Externals.h 27:16

What I have read is that this is the correct way to define a global structure. I think I would like to really put this into a Class but I wanted to understand this error.

Thanks

Kurt

9

The typedef does define sunposition as struct already, so don’t use struct again.
The way you do it there would virtually expand to something like that

struct struct sunposition { ... } Sun;

Which isn’t possible, so it’s interpreted as redefinition of an existing symbol.

Just write

sunposition Sun;
10

Thanks ScruffR for pointing this out.

I changed the line you mentioned but I guess the complier hadn’t gotten around to revealing that error to me yet.

I must apologize to the readers for posting something that is not very interesting. I fixed the problem with this code. I haven’t found where it was being included twice but it is obvious it is somewhere.

#ifndef Externals_H
#define Externals_H