sighup
sig_t sighup, sigint;
sighup = signal(SIGHUP, SIG_IGN);
signal(SIGHUP, sighup);
if (signal(SIGHUP, sighup) == SIG_ERR)
(void) signal(SIGHUP, sighup);
(void)signal(SIGHUP, sighup);
sighup(int sig)
sighup = 1;
if (sighup) {
sighup = 0;
static int sighup;
static void sighup(int);
(void)signal(SIGHUP, sighup);