[W]

[..]
  1. WAKEUP_CHARS
  2. WEXITSTATUS
  3. WIFEXITED
  4. WIFSIGNALED
  5. WIFSTOPPED
  6. WIN_DIAGNOSE
  7. WIN_FORMAT
  8. WIN_INIT
  9. WIN_READ
  10. WIN_RESTORE
  11. WIN_SEEK
  12. WIN_SPECIFY
  13. WIN_VERIFY
  14. WIN_WRITE
  15. WNOHANG
  16. WRERR_STAT
  17. WRITE
  18. WSTOPSIG
  19. WTERMSIG
  20. WUNTRACED
  21. W_OK
[..]