[W]

1. WAIT_ANY
2. WAIT_MYPGRP
3. WAKER_WAKES
4. WCOREDUMP
5. WEXITSTATUS
6. WIFEXITED
7. WIFSIGNALED
8. WIFSTOPPED
9. WNOHANG
10. WORD_ALLBITS
11. WORD_TYPE
12. WORKNUM
13. WRITECHAR
14. WSTOPSIG
15. WTERMSIG
16. WUNTRACED