Error: multiple definition (Beginner question)

Projects Programming
1

Hello everyone,
I'm new into Arduino Programming and to this Forum.
I have searched the forum and didn't find the solution to my problem. I assume it is simple, but I realy don't understand why this error occurs.
It says that some of my variables are defined multiple times, but they aren't (atleast I don't get where).
To get rid of the problem I created a new empty scetch with nothing in it other then some variable declerations (copied from the original script). Still the same error pops up. As you can see only some variables are "faulty" despite all of them are declared in the same way.
I get that you can get this error, when including multiple files and such, but I didn't do this, so I'm lost at this point.
I hope someone can descripe me where I did wrong, I would realy love to learn.
(I use the arduino IDE 1.8.19, if you need more information I will provide them)

Code:

float adc_ch0;
float adc_ch1;
float adc_read = 0.0;
float adc0_read = 0.0;
float adc1_read = 0.0;
float adc1_read_test = 0.0;
float test = 0.0;
float adc2_read = 0.0;
float adc3_read = 0.0;
void setup() {
  // put your setup code here, to run once:

}

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

}

Error:

Arduino: 1.8.19 (Windows 10), Board: "LOLIN D32 PRO, Disabled, Default, 80MHz, 921600, None"

c:/users/tafelsenf/appdata/local/arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/gcc8_4_0-esp-2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: C:\Users\Tafelsenf\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.4/tools/sdk/esp32/ld\librtc.a(rtc_analog.o): in function `adc1_read_test':

/home/qgu/git_tree/chip7.1_rtc/board_code/app_test/pp/rtc/rtc_analog.c:174: multiple definition of `adc1_read_test'; sketch\test.ino.cpp.o:C:\Users\Tafelsenf\Documents\Arduino\test/test.ino:7: first defined here

c:/users/tafelsenf/appdata/local/arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/gcc8_4_0-esp-2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: C:\Users\Tafelsenf\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.4/tools/sdk/esp32/ld\librtc.a(rtc_analog.o): in function `adc1_read':

/home/qgu/git_tree/chip7.1_rtc/board_code/app_test/pp/rtc/rtc_analog.c:224: multiple definition of `adc1_read'; sketch\test.ino.cpp.o:C:\Users\Tafelsenf\Documents\Arduino\test/test.ino:6: first defined here

c:/users/tafelsenf/appdata/local/arduino15/packages/esp32/tools/xtensa-esp32-elf-gcc/gcc8_4_0-esp-2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: C:\Users\Tafelsenf\AppData\Local\Arduino15\packages\esp32\hardware\esp32\2.0.4/tools/sdk/esp32/ld\librtc.a(rtc_analog.o): in function `adc2_read':

/home/qgu/git_tree/chip7.1_rtc/board_code/app_test/pp/rtc/rtc_analog.c:369: multiple definition of `adc2_read'; sketch\test.ino.cpp.o:C:\Users\Tafelsenf\Documents\Arduino\test/test.ino:9: first defined here

collect2.exe: error: ld returned 1 exit status

exit status 1

Fehler beim Kompilieren für das Board LOLIN D32 PRO.

Thank you in advance

3

These variable names conflict with global symbols defined in the board's core package. Pick different names.

float adc1_read = 0.0;
float adc1_read_test = 0.0;
float adc2_read = 0.0;
4

Thank you very much for your quick response.
Funny thing, I even renamed one and added a "_test" and then this name is also taken :smiley:
Could you tell me where I can look up these core package?

5

Here:
https://github.com/espressif/arduino-esp32

Another thing you can do, is to declare them locally, inside a function. You're in trouble partly because you made them global. You didn't show your code, but maybe you don't need them to be global...

6

Thank, you.
I will look up this possibility.