1 #include "apue.h" 2 #include <fcntl.h> 3  4  5 int main(int argc,char **argv) 6 { 7     if(argc != 2) 8         err_quit("usage:a.out <pathname>"); 9     if(access(argv[1],R_OK) < 0)10         err_ret("access error for %s",argv[1]);11     else12         printf("read access OK\n");13     if(open(argv[1],O_RDONLY)<0)14         err_ret("open error for %s\r\n",argv[1]);15     else16         printf("open for reading OK\r\n");17 18     exit(0);19 20 21     return 0;22 }23 ~