#include "apue.h"#include <errno.h>static voidsig_hup(int signo){	printf("SIGHUP received, pid = %d\n", getpid());}static voidpr_ids(char *name){	printf("%s: pid = %d, ppid = %d, pgrp = %d, tpgrp = %d\n",	    name, getpid(), getppid(), getpgrp(), tcgetpgrp(STDIN_FILENO));	fflush(stdout);}intmain(void){	char	c;	pid_t	pid;	pr_ids("parent");	if ((pid = fork()) < 0) {		err_sys("fork error");	} else if (pid > 0) {	/* parent */		sleep(5);		/* sleep to let child stop itself */		exit(0);		/* then parent exits */	} else {			/* child */		pr_ids("child");		signal(SIGHUP, sig_hup);	/* establish signal handler */		kill(getpid(), SIGTSTP);	/* stop ourself */		pr_ids("child");	/* prints only if we're continued */		if (read(STDIN_FILENO, &c, 1) != 1)			printf("read error from controlling TTY, errno = %d\n",			    errno);		exit(0);	}}