Form calls the user edit routine with the type parameter equal to U_ENTERFIELD just before the operator begins typing data into a field that has the user edit field set to yes. The edit_name parameter points to the name specified in the edit field name field in the field description form. If the edit field name is blank, then the edit_name parameter points to the field name. The old_value parameter points to the original contents of the field when the operator first entered the field.