utime.c

/**
   @file      utime.c
   @author    Mitch Richling <http://www.mitchr.me/>
   @Copyright Copyright 1998 by Mitch Richling.  All rights reserved.
   @brief     How to change mtime and atime on a file@EOL
   @Keywords  timestamp touch file atime mtime
   @Std       C89

              Note that utimes and futimes, both BSDisms, are not
              portable.  utime is part of POSIX.1 so should be most
              places.  Note that some OSes will allow strange values
              for the times (negative for example).  Such values will
              often cause stat to break on other OSes -- so don't set
              the time to impossible values.
              
*/

#include <sys/types.h>          /* UNIX types      POSIX */
#include <utime.h>              /* utime           POSIX */
#include <stdlib.h>             /* Standard Lib    ISOC  */
#include <errno.h>              /* error stf       POSIX */
#include <stdio.h>              /* I/O lib         ISOC  */

int main(int argc, char *argv[]);

int main(int argc, char *argv[]) {
  int retV;
  struct utimbuf utimeStruct;

  if(argc != 2) {
    printf("ERROR: A file name is required as the single argument.\n");
    exit(1);
  } /* end if */

  /* Set both to 0 time -- Number of seconds since 0 hours, 0
     minutes, 0 seconds, January 1, 1970, Coordinated Universal Time, without
     including leap seconds. */
  utimeStruct.actime  = 0;
  utimeStruct.modtime = 0;

  /* If the last arg is NULL, then both actime and modtime are set
     to the current time. */
  if(utime(argv[1], &utimeStruct) != 0) { 
    /* -1 is returned upon failure, 0 upon success. Different UNIX
       variants document different error conditions for this function.
       It is probably best to simply print the perror message.  As
       with most file system commands, you should retry in case of EINTR. */
    printf("ERROR: utime failed with error number: %d\n", errno);
    exit(1);
  } /* end if */
} /* end func main */