Multiple definition of `display' ERROR with HTTC-AB02

#1

I am using CubeCell AB02. https://heltec.org/project/htcc-ab02/
I am trying to combine LoRaSender.ino and **SH1107_SimpleDemo_i2C
But I get a compile error " LoRaWan_APP.cpp.o:(.bss+0xcc): multiple definition of `display’"
Has anyone seen this and if so, what can I do to fix it?

Thanks, Chris

#2

Refer to the：

#3

Specifically in that factorytest example, the line:
extern SH1107Wire display;

which means you get a reference to an existing variable (display) rather than creating a new one (which is why you get an error, it’s already defined and you’re trying to create a new one in your sketch).

#4

Thanks, I thought as much, but I did not know how to fit the issue I will try to replace the line with extern SH1107Wire display;