I didn’t use -Werror but no warning about it showed up either. The project uses a semi-custom toolchain for a microcontroller, but I’m not using it to compile this code. I have another file with an entrypoint which tests some classes to be used by the microcontroller. The EEPROM in the code example is actually a macro for a class I’ve written that emulates the EEPROM library by writing and reading to a file on disk.

It’s a bit of a mess but this dual toolchain setup seemed easier than emulating the board and peripherals in it’s entirety. I might have to retry that though using Wokwi.