Example:
	#include <stdio.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <sys/stat.h>
	#include <linux/vt.h>
	#include <sys/types.h>
	#include <sys/ioctl.h>

	#define ERROR -1

	void main()
	{
          int fd;
          int freecon;

	  if ((fd = open("/dev/console", O_NOCTTY)) == ERROR) {
	     perror("open");
	     exit(ERROR);
	  }

	  printf("w00w00!\n\n");

          if (ioctl(fd, VT_OPENQRY, &freecon) == ERROR) {
             perror("ioctl");
	     close(fd);
	     exit(ERROR);
          }

          printf("The first free (non opened) console is tty%d\n", freecon);
          close(fd);
      }