Looking for help: Retroarch keyboard config

[Felsir]

I'm trying to run retroarch on my cab to play gameboy games (those shaders look perfect).
So far I am unsuccessful in configuring the keyboard- I simply don't know what valid options are for the settings:

Code: [Select]

input_player1_b_btn = "nul"
does anyone know the correct settings that match the default mame setup? (so valid keys for left alt, left control etc.)

thanks in advance.