Having issues understanding what "#define GET_STATUS" does

Question

I am trying to use a Waveshare 4.2inch e-paper display with an Adafruit Feather Adalogger M0, but am having issues with two separate instances of #define GET_STATUS being defined differently in different locations. More specifically, in the Demo Library (download) for the Waveshare display, one of the files (epd4in2.h) defines GET_STATUS as 0x71. However, in a file (USBCore.h) I downloaded from the board manager in the ArduinoIDE to be able to support the Feather Adalogger, GET_STATUS is defined as 0.

I've tried messing with the values to see if making them match (both as 0x71 and both as 0) would solve the issue, but it didn't change anything. I can't find any information about what GET_STATUS in general, so I'm unsure what I can even try to fix this issue. Furthermore, I can't find any instances of GET_STATUS being used, so I'm unsure what its significance even is. So, basically, my questions are: 1) what is the significance of GET_STATUS, and 2) how can I reconcile it being used differently in two different places?

Below is the code I'm trying to run (it's the demo code from Waveshare), and the libraries other than "<SPI.h>" are in the demo library download from Waveshare.

#include <SPI.h>
#include "epd4in2.h"
#include "imagedata.h"
#include "epdpaint.h"

#define COLORED     0
#define UNCOLORED   1

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Epd epd;

  if (epd.Init() != 0) {
    Serial.print("e-Paper init failed");
    return;
  }

  /* This clears the SRAM of the e-paper display */
  epd.ClearFrame();

  /**
    * Due to RAM not enough in Arduino UNO, a frame buffer is not allowed.
    * In this case, a smaller image buffer is allocated and you have to 
    * update a partial display several times.
    * 1 byte = 8 pixels, therefore you have to set 8*N pixels at a time.
    */
  unsigned char image[1500];
  Paint paint(image, 400, 28);    //width should be the multiple of 8 

  paint.Clear(UNCOLORED);
  paint.DrawStringAt(0, 0, "e-Paper Demo", &Font24, COLORED);
  epd.SetPartialWindow(paint.GetImage(), 100, 40, paint.GetWidth(), paint.GetHeight());

  paint.Clear(COLORED);
  paint.DrawStringAt(100, 2, "Hello world", &Font24, UNCOLORED);
  epd.SetPartialWindow(paint.GetImage(), 0, 64, paint.GetWidth(), paint.GetHeight());
  
  paint.SetWidth(64);
  paint.SetHeight(64);

  paint.Clear(UNCOLORED);
  paint.DrawRectangle(0, 0, 40, 50, COLORED);
  paint.DrawLine(0, 0, 40, 50, COLORED);
  paint.DrawLine(40, 0, 0, 50, COLORED);
  epd.SetPartialWindow(paint.GetImage(), 72, 120, paint.GetWidth(), paint.GetHeight());
  
  paint.Clear(UNCOLORED);
  paint.DrawCircle(32, 32, 30, COLORED);
  epd.SetPartialWindow(paint.GetImage(), 200, 120, paint.GetWidth(), paint.GetHeight());

  paint.Clear(UNCOLORED);
  paint.DrawFilledRectangle(0, 0, 40, 50, COLORED);
  epd.SetPartialWindow(paint.GetImage(), 72, 200, paint.GetWidth(), paint.GetHeight());

  paint.Clear(UNCOLORED);
  paint.DrawFilledCircle(32, 32, 30, COLORED);
  epd.SetPartialWindow(paint.GetImage(), 200, 200, paint.GetWidth(), paint.GetHeight());

  /* This displays the data from the SRAM in e-Paper module */
  epd.DisplayFrame();

  /* This displays an image */
  epd.DisplayFrame(IMAGE_BUTTERFLY);

  /* Deep sleep */
  epd.Sleep();
}

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

}

When I run the code, I get the following messages

In file included from /home/beingpool/Arduino/epd4in2-demo/epd4in2-demo.ino:28:
/home/<user>/Arduino/libraries/epd4in2/epd4in2.h:64: warning: "GET_STATUS" redefined
   64 | #define GET_STATUS                                  0x71
      | 
In file included from /home/beingpool/.arduino15/packages/adafruit/hardware/samd/1.7.11/cores/arduino/Arduino.h:157,
                 from /home/beingpool/.var/app/cc.arduino.IDE2/cache/arduino/sketches/96EFEDEA56FF573B678089A960FFC685/sketch/epd4in2-demo.ino.cpp:1:
/home/beingpool/.arduino15/packages/adafruit/hardware/samd/1.7.11/cores/arduino/USB/USBCore.h:23: note: this is the location of the previous definition
   23 | #define GET_STATUS     0
      | 

Answer 1

There is no generic meaning in GET_STATUS. Apparently both libraries use the very same identifier for their own different purpose.

If you do not use GET_STATUS in your sketch, you can remove the definition before the inclusion of "epd4in2.h", like this:

#include <SPI.h>
#undef GET_STATUS
#include "epd4in2.h"

// ...