Compiling source with Arduino.h with avr-g++

Question

How should I include the Arduino libraries when I'm compiling from the the command line? I tried to do it like this:

avr-g++ -g -Os -Wall -mcall-prologues -mmcu=atmega328p -fno-exceptions -o blink.obj blink.cpp -L. -lutil -I"C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino" -I"C:\Program Files (x86)\Arduino\hardware\arduino\avr\variants\standard" -I"D:\Projects\Arduino" -I"C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores"

but it returns undefined reference to the function that I am trying to use.

Arduino version: 1.8.2

Answer 1

You need to do a whole lot more than just run the one command.

You need to compile each individual source file for the libraries you want (using -c to just compile and not link), then (ideally) archive them into a library file. Do the same for the core. Then you need to add paths to your sketch compilation command pointing to where the header files are for those libraries, and compile the sketch to an object file (again with -c). Finally you need to link everything together into an ELF file, and convert that to a HEX file.

TBH you're best off using an already-existing Makefile project, or arduino-builder.