-APUE-:
fig10.7, simple, incomplete implementation of sleep.
fig10.8, another(imperfect) implementation of sleep.
fig10.9, call sleep2 from a program that catches other signals.
fig10.10, calling read with a timeout.
fig10.11, calling read with a timeout, using longjmp.
-APUE-:
fig10.12, an implementation of sigaddset, sigdelset and sigismember.
fig10.14, print the signal mask for process.