4.6.c

#include <stdio.h>
#include <stdlib.h>
#include <utime.h>
#include <fcntl.h>

int main(int argc, char **argv)
{
    int             i,fd;
    struct stat     statbuf;
    struct utimbuf  timebuf;

    for (i = 1; i < argc; i++) {
        if (stat(*(argv + i), &statbuf) < 0) {
            printf("%s : stat error!\n", *(argv + i));
            continue;
        }

        if ((fd = open(*(argv + i), O_RDWR | O_TRUNC)) < 0) {
            printf("%s : open error!\n", *(argv + i));
            continue;
        }

        close(fd);

        timebuf.actime  = statbuf.st_atime;
        timebuf.modtime = statbuf.st_mtime;

        if (utime(*(argv + i), &timebuf) < 0) {
            printf("%s : utime error!\n", *(argv + i));
            continue;
        }
    }

    return 0;
}