I'm moving from the Arduino IDE to the Atmel Studio environment. I have already succesfully written a couple of firmwares without relying on any Arduino library.
I'm now adding UART support by including Andygock library (https://github.com/andygock/avr-uart).
I placed the uart.h and uart.c files in the project directory and included the "uart.h" file in the main.c file.
The errors I get are the following:
"undefined reference to `uart0_available' "
"ld returned 1 exit status."
The same errors occur if I try to call any another function of the library.
I attach the compile output of the Atmel Studio 7.0
Thank you in advance for your support.