#include "apue.h"#include <sys/types.h>#include <utime.h> int main(){ struct utimbuf tbuf; // both type of tbuf.actime and time() is time_t, // but why can't this assignment happen? tbuf.actime = time(); tbuf.modtime = time(); if(utime("hello.c", &tbuf) < 0) err_sys("utime error for hello.c"); }