Thanks for the response.
I went through the issues and solved it!
Anyway in my question I forgot to add some informations as I want to use the gpio port of RPi3. My apologies...
The solutions I found are the following.
First I followed some suggestions (I added enable_uart=1 on config.txt in /boot, I removed all occurences of ttyAMA0 in cmdconfig.txt, I disabled getty@ttyAMA0 on systemctl) founded googling for my problem.
After that changes I reboot, and I tried with pyserial library that worked for me.
Further I tried the code on this guide
http://www.raspberry-projects.com/pi/programming-in-c/uart-serial-port/using-the-uartmodifiing the port ttyAMA0 to ttyS0 as suggested. And that worked too!
In this way I had my RPi3 working with gpio pins without wiringPi libraries( can't understand if serial in wiringPi uses the default pins TX, RX of RPi3!).
Now I'm working on a bluetooth issue to make it works in my arch system.
Thanks a lot!