show_disk_mode
show_disk_mode = SHOW_FIRST_ONLY;
show_disk_mode = SHOW_SECOND_ONWARDS;
show_disk_mode = SHOW_ALL;
switch (show_disk_mode) {
if ((do_disk & PRINT_VERTICAL) && show_disk_mode != SHOW_FIRST_ONLY)
enum show_disk_mode show_disk_mode = SHOW_ALL;