A new PlatformIO user coding wrong, getting multiple definition & first defined here errors

[miguelmlr9]

Hi, there are a better way:
in the Power.h file you just need to use ‘inline’ before the global variable/objects, like:

//global vars
inline float shuntvoltage_A = 0;

//global objects
inline Adafruit_INA219 ina219_A;
inline Adafruit_INA219 ina219_B(0x41);

with that you can declare and define the variable/object in the .h file, so isn’t neccesary to do the definition in the .cpp file.

read more: C++ Global variable declaration - Stack Overflow

also, if is compiling fine, but compiler show some warnings I recommend to configure your platformio.ini file to compile with a newer version of C++, like that:

build_unflags = -std=gnu++11 ;Old version
build_flags = -std=gnu++2a  ;Use new version

You can read this:

Which C++ standard am I using?

PlatformIO follows the compilation settings of the original frameworks, so e.g. for ESP32 + Arduino (core 1.0.6), C++11 is the standard used in there in the Arduino IDE, and so PlatformIO has that as a default. If the used compiler is capable of a higher C++ standard and if the code is compilable for that higher standard, build_unflags and build_flags can be used. If we’re talking about the standard ESP32 + Arduino case here, note that PlatformIO is currently lagging behind regarding the used …

I just open this account to share this solution, because I had the same problem as meathome2017, so I hope this can be helpfull to someone in the future