contain Latin-1 characters.
@c SYMBOL in the definition of @c KEYSEQ must be the return value of
-the minput_event_to_key () function.
+the minput_event_to_key () function. Under the X window system, you
+can quickly check the value using the @c xev command. For example,
+the return key, the backspace key, and the 0 key on the keypad are
+represented as @c (Return) , @c (BackSpace) , and @c (KP_0)
+respectively. If the shift, control, meta, alt, super, and hyper
+modifiers are used, they are represented by the S- , C- , M- , A- , s-
+, and H- prefixes respectively in this oreder. Thus, "return with
+shift with meta with hyper" is @c (S-M-H-Return) . Note that "a with
+shift" .. "z with shift" are represented simply as A .. Z . Thus "a
+with shift with meta with hyper" is @c (M-H-A) .
@c INTEGER in the definition of @c KEYSEQ must be a valid character
code.