#include <stdio.h>
#include <dos.h>  
#include <fcntl.h>

void main(int argc, char *argv[])
 {
	union
	 {
		struct Date
  		 {
			unsigned int day:5;
			unsigned int month:4;
			unsigned int years:7;
		 } bits;
		unsigned value;
	 } date;

	union
	 {
	  	struct Time
		 {
			unsigned seconds:5;
			unsigned minutes:6;
			unsigned hours:5;
		 } bits;
		unsigned value;
    } time;

    int handle;

    if (_dos_open(argv[1], O_RDONLY, &handle))
			fprintf(stderr, "Error opening source file\n");
    else
		{
			date.bits.day = 4;
			date.bits.month = 7;
			date.bits.years = 17;			// 1980 + 17
			time.bits.hours = 12;
			time.bits.minutes = 0;
			time.bits.seconds = 0;

			if (_dos_setftime(handle, date.value, time.value))
				printf("Error setting date/time stamp\n");
			_dos_close(handle);
		}
 }