Listing 4. Example Truncated String
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or 
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */


#include <stdlib.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <asm/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdint.h>

#include <linux/input.h>


int main (int argc, char **argv) {

  int fd = -1;
  char name[256]= "Unknown";

  /* ioctl() requires a file descriptor, so we check we got one, and then open it */
  if (argc != 2) {
    fprintf(stderr, "usage: %s event-device - probably /dev/input/event0\n", argv[0]);
    exit(1);
  }
  if ((fd = open(argv[1], O_RDONLY)) < 0) {
    perror("evdev open");
    exit(1);
  }

  /* suck out the name information 
   * return value is the length of the name, for success 
   * or -EFAULT for failure
   */
  if(ioctl(fd, EVIOCGNAME(sizeof(name)), name) < 0) {
      perror("evdev ioctl");
  }

  printf("The device on %s says it's name is %s\n", argv[1], name);

  close(fd);

  exit(0);
}