key_keycode/[3,4] key_keycode(+Displayable, ?Key, ?Keycode, ?Index)
key_keycode(?Key, ?Keycode, ?Index)
Translates between keys and keycodes.
Under X11, physical keys are mapped to unique server-dependent keycodes and keycodes are mapped to a list of server-independent keysyms.
Displayable is a ProXL Displayable. If omitted, the default Display is used.
Key is a key name, as given by keysym/2.
Keycode is an integer, between 8 and 255, corresponding to
the Key.
Index is an integer, typically 0 or 1, that identifies
which of the keysyms attached to Keycode corresponds to
Key. The usual case is that Keysym number 0 corresponds to
the lower case variant of the key, and Keysym number 1 to the upper case
variant, if it exists.