#include "apue.h"#include <fcntl.h>intmain(int argc, char *argv[]){	if (argc != 2)		err_quit("usage: a.out <pathname>");	if (access(argv[1], R_OK) < 0)		err_ret("access error for %s", argv[1]);	else		printf("read access OK\n");	if (open(argv[1], O_RDONLY) < 0)		err_ret("open error for %s", argv[1]);	else		printf("open for reading OK\n");	exit(0);}