```c
#include <gio/gio.h>
#include <glib.h>

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define BLOCK_SIZE 1024

static gboolean
gio_read_socket (GIOChannel     *channel,
                 GIOCondition    condition,
                 gpointer        data)
{

    char buf[1024];
    gsize bytes_read;
    GError *error = NULL;
    g_print("gio_read_socket\n");

    if (condition & G_IO_HUP) return FALSE; /* this channel is done */

    g_io_channel_read_chars (channel, buf, sizeof (buf), &bytes_read,
            &error);
    g_assert (error == NULL);

    buf[bytes_read] = '\0';

    g_print ("%s", buf);

    int *a = data;
    *a = *a + 1;

    return TRUE;
}

gboolean
idleCpt (gpointer user_data){

   int *a = user_data;
   g_print("hello\n");
   g_print("%d\n", *a);
   sleep(1);

   return TRUE;
}
int
main (int argc, char **argv)
{

  GSocket * s_udp;
  GError *err = NULL;
  int idIdle = -1, dataI = 0;
  guint16 udp_port = 4001;
  GSocketAddress * gsockAddr = G_SOCKET_ADDRESS(g_inet_socket_address_new(g_inet_address_new_any(G_SOCKET_FAMILY_IPV4), udp_port));
  s_udp = g_socket_new(G_SOCKET_FAMILY_IPV4,
                    G_SOCKET_TYPE_DATAGRAM,
                    G_SOCKET_PROTOCOL_UDP,
                    &err);
  g_assert(err == NULL);

  if (s_udp == NULL) {
    g_print("ERREUR");
    exit(1);
  }


  if (g_socket_bind (s_udp, gsockAddr, TRUE, NULL) == FALSE){

   g_print("Erreur bind\n");
   exit(1);

  }

  g_assert(err == NULL);

  int fd = g_socket_get_fd(s_udp);

  GIOChannel* channel = g_io_channel_unix_new(fd);
  guint source = g_io_add_watch(channel, G_IO_IN,
                              (GIOFunc) gio_read_socket, &dataI);

  g_io_channel_unref(channel);


   GMainLoop *loop = g_main_loop_new(NULL, FALSE);
   idIdle = g_idle_add(idleCpt, &dataI);
   g_main_loop_run(loop);
}
```
Build with
```bash
gcc -o ex1 $(pkg-config --cflags glib-2.0 gio-2.0) ex1.c $(pkg-config --libs glib-2.0 gio-2.0)
```