#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <err.h>
#include <unistd.h>

int
main(int argc, char *argv[])
{
	int fd;
	off_t seekdata, seekhole;
	size_t len;
	ssize_t rsiz;

	if (argc != 2)
		errx(1, "Usage: copysame <file>");
	fd = open(argv[1], O_RDWR, 0);
	if (fd < 0)
		err(1, "can't open %s", argv[1]);

	/* Copy the first megabyte to the second megabyte. */
	seekdata = 0;
	seekhole = 1048576;
	rsiz = 1048576;
	len = copy_file_range(fd, &seekdata, fd, &seekhole,
	    rsiz, 0);
}