信号处理函数

9.1 alarm()

9.2 kill()

9.3 sigaction()

9.4 pause()

9.5 sigaddset()

9.6 sigdelset()

9.7 sigemptyset()

9.8 sigfillset()

9.9 sigismember()

9.10 signal()

9.11 sigpending()

9.12 sigprocmask()

9.13 sleep()

9.14 ferror()

9.15 perror()

9.16 strerror()

9.17 mkfifo()

9.18 pclose()

9.19 popen()