How to compile a simple Arduino program?

Question

I am starting to learn / program the Arduino and I don't understand why I am getting syntax errors upon compiling my program in Visual Studio 2017 with Visual Micro or with the Arduino IDE.

Compiling output error from Visual Studio 2017:

sketch\SketchIncomeEligible.ino.cpp.o:(.text.setup+0x0): undefined reference to `WiFi_Setup()'

sketch\SketchIncomeEligible.ino.cpp.o: In function `setup':

C:\Users\C113850\source\repos\Income_Eligible_Price_Display\src\SketchIncomeEligible\SketchIncomeEligible/SketchIncomeEligible.ino:6: undefined reference to `WiFi_Setup()'

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board Adafruit Feather HUZZAH ESP8266.

Compiling error from Arduino IDE:

Arduino: 1.8.9 (Windows 10), Board: "Adafruit Feather HUZZAH ESP8266, 80 MHz, Flash, 4M (1M SPIFFS), v2 Lower Memory, Disabled, None, Only Sketch, 115200"

sketch\SketchIncomeEligible.ino.cpp.o:(.text.setup+0x0): undefined reference to `WiFi_Setup()'

sketch\SketchIncomeEligible.ino.cpp.o: In function `setup':

C:\Users\C113850\source\repos\Income_Eligible_Price_Display\src\SketchIncomeEligible\SketchIncomeEligible/SketchIncomeEligible.ino:6: undefined reference to `WiFi_Setup()'

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board Adafruit Feather HUZZAH ESP8266.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

The following is my code:

SketchWiFi.h file:

#ifndef _SKETCHWIFI_h
#define _SKETCHWIFI_h

int WiFi_Setup();

#endif

SketchWiFi.c file:

#include "SketchWiFi.h"

int WiFi_Setup()
{
  // put your setup code here, to run once:

  return 1; // Successful
}

Sketch.ino file:

#include "SketchWiFi.h"

void setup() {
  Serial.begin(115200);
  Serial.println("Begin setup");

  WiFi_Setup();

  Serial.println("End setup");
}

void loop() {
  // put your main code here, to run repeatedly:
}

Directory structure:

Project Structure in Visual Studio 2017

Project structure in Arduino IDE

This might help you : github.com/arduino/Arduino/wiki/Build-Process — Jona
– Jona, Commented Apr 24, 2019 at 20:50
You don't seem to use the Arduino IDE to compile your project. How do you force SketchWiFi.c to be one of your source files ? Add a SketchWiFi.cpp to your project with that code. — datafiddler
– datafiddler, Commented Apr 24, 2019 at 20:50
Yes. I have compiled in both environments, Visual Studio 2017 and Arduino IDE. — PKonstant
– PKonstant, Commented Apr 24, 2019 at 21:03

PKonstant · Accepted Answer · 2019-04-24 22:13:04Z

2

Per a suggestion posted, I read on GitHub the following:

No pre-processing is done to files in a sketch with any extension other than .ino. Additionally, .h files in the sketch are not automatically #included from the main sketch file. Further, if you want to call functions defined in a .c file from a .cpp file (like one generated from your sketch), you'll need to wrap its declarations in an 'extern "C" {}' block that is defined only inside of C++ files.

So that explains my problem. I enclosed my simple function 'WiFi_Setup()' with in a class and now it compiles successfully.

class WifiNetwork
{
protected:

public:
    void WiFi_Setup();
};

It seems Arduino wants everything to live in classes.

edited Apr 24, 2019 at 22:13

answered Apr 24, 2019 at 22:03

PKonstant

1,0084 gold badges22 silver badges45 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

julovi Over a year ago

could you show how the .h, and .c files were modified?

Collectives™ on Stack Overflow

How to compile a simple Arduino program?

Compiling output error from Visual Studio 2017:

Compiling error from Arduino IDE:

SketchWiFi.h file:

SketchWiFi.c file:

Sketch.ino file:

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

Compiling output error from Visual Studio 2017:

Compiling error from Arduino IDE:

SketchWiFi.h file:

SketchWiFi.c file:

Sketch.ino file:

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related