Event.functionKey

Description

Is the current keypress a function key? (Read Only)

Returns true if the current keypress is an arrow key, page up, page down, backspace, etc. key. If this key needs special processing in order to work in text editing, functionKey is on.

using UnityEngine;

public class Example : MonoBehaviour
{
    // Detects if a function Key was pressed. If a
    // function key was pressed, prints its key code.
    void OnGUI()
    {
        Event e = Event.current;
        if (e.functionKey)
        {
            Debug.Log("Pressed: " + e.keyCode);
        }
    }
}