As noted in Section 20.3, sigaction() is more portable than signal() for establishing a signal handler. Replace the use of signal() by sigaction() in the program in Example 20-7 (sig_receiver.c).

Write a program that shows that when the disposition of a pending signal is changed to be SIG_IGN, the program never sees (catches) the signal.

Write programs that verify the effect of the SA_RESETHAND and SA_NODEFER flags when establishing a signal handler with sigaction().

Implement the siginterrupt() function described in Section 21.5 using sigaction().