Form calls the user edit routine with the type parameter equal
to U_FIRSTFORM each time the beginning form in a formfile should
be displayed on the screen. Either the operator pushes the FIRSTFORM key, or
the next form automatically displayed is the beginning form. In the latter case,
form restarts the series of forms and redisplays the beginning form in
the formfile. Form calls the user edit routine before the form
is displayed on the screen. If the user edit routine returns an error message,
form displays the message and the new form is not put on the screen.
Form sets the old_value parameter to point to the current form
name, and the new_value parameter to point to the name of the new form
(the beginning form).