#include <stdint.h>
#include <stdio.h>

#include <poll.h>
#include <termios.h>
#include <unistd.h>

int main() {

  struct termios old, new;

  tcgetattr(STDIN_FILENO, &old);

  new = old;

  new.c_lflag &= ~(ECHO | ICANON);
  new.c_cc[VMIN] = 0;  // bytes read to return
  new.c_cc[VTIME] = 0; // time before return

  tcsetattr(STDIN_FILENO, TCSANOW, &new);

  struct pollfd poller[1];

  poller[0].fd = STDIN_FILENO;
  poller[0].events = POLLIN;

  printf("Pressed characters:\n");

  uint8_t run = 1;

  while (run) {
    int events = poll(poller, 1, -1);
    if (events > 0 && poller[0].revents & POLLIN) {
      char buffer[10];
      uint16_t length = read(STDIN_FILENO, buffer, sizeof(buffer));
      if (length > 0) {
        uint8_t i;
        for (i = 0; i < length; i++) {
          printf(" %x", buffer[i]);
          if (buffer[i] == 'Q')
            run = 0;
        }
        printf("\n");
      }
    }
  }

  tcsetattr(STDIN_FILENO, TCSANOW, &old);

  return 0;
}