/* gcc -D_GNU_SOURCE -o lseek lseek.c */

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

char buffer[63*1024];

int
main(int argc, char *argv[])
{
  loff_t offset;
  
  int fildes = open(argv[1], O_RDONLY|O_LARGEFILE, 0600);

  if (fildes == -1) {
    printf("errno=%d %s\n", errno, strerror(errno));
    exit(1);
  }
  offset = (loff_t) strtoul(argv[2],NULL, 0) * 1024 * 1024;
  offset =  lseek(fildes, offset, SEEK_SET);

  printf("offset=%Lu\n", offset);
  read(fildes, buffer, sizeof(buffer));

  return 0;
}