#include "apue.h"#include <pwd.h>static voidmy_alarm(int signo){	struct passwd	*rootptr;	printf("in signal handler\n");	if ((rootptr = getpwnam("root")) == NULL)			err_sys("getpwnam(root) error");	alarm(1);}intmain(void){	struct passwd	*ptr;	signal(SIGALRM, my_alarm);	alarm(1);	for ( ; ; ) {		if ((ptr = getpwnam("sar")) == NULL)			err_sys("getpwnam error");		if (strcmp(ptr->pw_name, "sar") != 0)			printf("return value corrupted!, pw_name = %s\n",					ptr->pw_name);	}}