[o]

1. off_t
2. offsetof
3. old_stat
4. old_utsname
5. oom
6. open
7. open_aux
8. open_mouse
9. open_namei
10. origin
11. out_port_type
12. outb
13. outb_p
14. output_byte
15. outsw
16. outw
17. overlap