event-driven 10 PRINT program using libev

gistfile1.c

#include <ev.h>
#include <locale.h>
#include <stdio.h>
#include <wchar.h>
#include <termios.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>

static ev_timer timer_watcher;
static ev_io stdin_watcher;
static ev_signal sigint_watcher;

static unsigned int seed;

void set_single_char(int fd, struct termios *stored_termios) {
  struct termios *st = malloc(sizeof(struct termios));
  tcgetattr(fd, st);
  memcpy(stored_termios, st, sizeof(*st));

  st->c_iflag &= ~(INLCR | IGNCR | ICRNL | IXON);
  st->c_lflag &= ~(ECHO | ECHONL | ICANON);
  st->c_cflag &= ~CSIZE;
  st->c_cflag |= CS8;

  tcsetattr(fd, TCSANOW, st);
  free(st);
}

static void stop(struct ev_loop *loop) {
  ev_io_stop(loop, &stdin_watcher);
  ev_timer_stop(loop, &timer_watcher);
  ev_signal_stop(loop, &sigint_watcher);
}

static void stdin_cb(struct ev_loop *loop, ev_io *w, int revents) {
  char buf[256];
  if (revents & EV_READ) {
    read(STDIN_FILENO, buf, 255);
  }
  stop(loop);
}

static void sigint_cb(struct ev_loop *loop, ev_signal *w, int revents) {
  stop(loop);
}

static void timer_cb(struct ev_loop *loop, ev_timer *w, int revents) {
  putwchar(0x2571 + (rand_r(&seed) & 1));
  fflush(stdout);
}

int main(int argc, char** argv) {
  struct ev_loop *loop = ev_default_loop(EVFLAG_SIGNALFD | EVBACKEND_SELECT);
  struct termios *stored_termios = malloc(sizeof(struct termios));

  setlocale(LC_ALL, "");
  set_single_char(STDIN_FILENO, stored_termios);
  seed = time(NULL);

  ev_io_init(&stdin_watcher, stdin_cb, STDIN_FILENO, EV_READ);
  ev_io_start(loop, &stdin_watcher);

  ev_signal_init(&sigint_watcher, sigint_cb, SIGINT);
  ev_signal_start(loop, &sigint_watcher);

  ev_timer_init(&timer_watcher, timer_cb, 0.0, 0.025);
  ev_timer_start(loop, &timer_watcher);

  ev_run(loop, 0);

  putwchar(L'\n');
  tcsetattr(STDIN_FILENO, TCSANOW, stored_termios);
  free(stored_termios);

  return 0;
}