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Prints a HID device to stdout
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <signal.h>
void handler (int sig)
printf ("\nexiting...(%d)\n", sig);
void perror_exit (char *error)
int main (int argc, char *argv[])
struct input_event ev[64];
int fd, rd, value, size = sizeof (struct input_event);
char name[256] = "Unknown";
char *device = NULL;
//Setup check
if (argv[1] == NULL){
fprintf(stderr, "Please specify (on the command line) the path to the dev event interface device\n");
exit (0);
if ((getuid ()) != 0)
fprintf (stderr, "You are not root! This may not work...\n");
if (argc > 1)
device = argv[1];
//Open Device
if ((fd = open (device, O_RDONLY)) == -1) {
fprintf (stderr, "%s is not a vaild device.\n", device);
//Print Device Name
ioctl (fd, EVIOCGNAME (sizeof (name)), name);
fprintf (stderr, "Reading From : %s (%s)\n", device, name);
//Stop propagation of the event
ioctl (fd, EVIOCGRAB, 1);
while (1) {
if ((rd = read (fd, ev, size * 64)) < size)
value = ev[0].value;
if (value != ' ' && ev[1].value == 1 && ev[1].type == 1){ // Only read the key press event
int val = ev[1].code - 1;
if (val == 27) {
fprintf (stdout, "\n");
fprintf (stdout, "%d", val);
return 0;
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