Chap 7. Event-Driven Programming

(Chap 6. signal - 동기/비동기, Signal(signum, SIG_IGN or SIG_DFL or function))\

Chap 7. Event-Driven Programming

* Lcurses 

* sleep / alarm

* Time - real / virtual(user) / profile(user+kennel)

* struct Itimerval - value, interval -> 반복 알람

* setitimer(time kind, itimerval, old itimerval)

* multi signal 

* sigaction - struct sigaction.sa_handler - 함수 , sa_flag - 옵션, sa_mask 

* sigset_t - emptyset, addset -> sa_mask로 값주기

* 중요데이터 signal 막기 _ sigprocmask(SIG_BLOCK, new sigset_t, old_sigset_t)