passing a struct by reference in a class

Projects Programming
1

I'm looking to make some upgrades to a library but i have not worked a lot with classes. The problem i'm having is i have a bunch of ring buffer code that i'm trying to recycle. The ring buffer code works by handing a function a struct by reference, the function then modifies the struct. the code is very flexible this was because a single function can be handed many different structs as long as the structure of the struct is the same. for example..

void ringBuf_put(struct ringBuf * _this, int data){ some stuff..}

struct ringBuf{
int buffer[10];
int head;
int tail;
int count;
};

struct ringBuf one;
struct ringBuf two;

ringBuf_put(&one, 17);
ringBuf_put(&two, 21);

This code works perfectly fine in arduino environment. Now i'm trying to wrap this same code into a class to use in a library and it's not working. if i try to compile this code in the library or just in arduino i get an error. (this is just test code but the real code is almost identical but much longer)

FastTransferTest:21: error: prototype for 'void fast::otherstuff(fast::test*)' does not match any in class 'fast'
FastTransferTest:7: error: candidate is: void fast::otherstuff(test*)

class fast{
  public:
  void stuff(int hi);
  private:
  void otherstuff(struct test * hy);
  struct test{
    int th;
    int irm;
  };
  
  test kick;
  
};

void fast::stuff(int hi){
  
}

void fast::otherstuff(struct test * hy){
  
}

void setup()
{ 
}
void loop()
{
}

but if i compile this code it compiles just fine.

class fast{
  public:
  void stuff(int hi);
  private:
//converting the struct pointer to an integer is the only change
  void otherstuff(int hy);
  struct test{
    int th;
    int irm;
  };
  
  test kick;
  
};

void fast::stuff(int hi){
  
}
//converting the struct pointer to an integer is the only change
void fast::otherstuff(int hy){
  
}

void setup()
{ 
}
void loop()
{
}

is it not possible to pass a struct by reference inside a class or am i doing something wrong?
maybe a library that i need to add?

2

Try this...

class fast{
  public:
  void stuff(int hi);
  private:
  struct test{
    int th;
    int irm;
  };
  void otherstuff(struct test * hy);
  
  test kick;
  
};
3

that works

i take it i need to declare the struct before the function the references it.

thanks nice catch.. :slight_smile:

4

Arduino: 1.8.3 (Windows 7), Board: "Arduino/Genuino Uno"

In file included from C:\Users\NASSAR K I\Documents\Arduino\libraries\Moving_clcock_working\DS3231.cpp:22:0:

C:\Users\NASSAR K I\Documents\Arduino\libraries\Moving_clcock_working\DS3231.h:27:42: fatal error: hardware/avr/HW_AVR_defines.h: No such file or directory

#include "hardware/avr/HW_AVR_defines.h"

^

compilation terminated.

Multiple libraries were found for "RTClib.h"
Used: C:\Users\NASSAR K I\Documents\Arduino\libraries\RTClib
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\RTCLib_by_NeiroN
Multiple libraries were found for "SoftwareSerial.h"
Used: C:\Users\NASSAR K I\Desktop\arduino-1.8.3\hardware\arduino\avr\libraries\SoftwareSerial
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\EspSoftwareSerial
Multiple libraries were found for "Adafruit_GFX.h"
Used: C:\Users\NASSAR K I\Documents\Arduino\libraries\Moving_clcock_working
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\LEDDotMatrixClock
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\Adafruit-GFX-Library-master
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\LEDDotMatrixClock
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\Adafruit-GFX-Library-master
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\LEDDotMatrixClock
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\Adafruit-GFX-Library-master
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\LEDDotMatrixClock
Not used: C:\Users\NASSAR K I\Documents\Arduino\libraries\Adafruit-GFX-Library-master
exit status 1
Error compiling for board Arduino/Genuino Uno.

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option enabled in File -> Preferences.
This sketch not compiling please help

5

@nassarki:
What does your problem have to do with the dead thread you are trying to hijack?