Dbus power event example

dbus_listen.cpp

#include <stdio.h>
#include <dbus/dbus.h>
#include <dbus/dbus-glib-lowlevel.h>
#include <dbus/dbus-glib.h>
#include <glib.h>

static DBusHandlerResult dbus_filter (DBusConnection *connection, DBusMessage *message, void *user_data)
{
  printf("dbus_filter called");

  if (dbus_message_is_signal(message, "org.freedesktop.PowerManagement", "PowerSaveStatusChanged"))  
  {
    printf("Power Save Status CHANGED\n");
    return DBUS_HANDLER_RESULT_HANDLED;
  }

  return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}

int main()
{
  DBusConnection* connection;
  DBusError       error;
  /* glib main loop */
  GMainLoop *loop;
  loop = g_main_loop_new(NULL, FALSE);
  dbus_error_init(&error);
  connection = dbus_bus_get(DBUS_BUS_SESSION, &error);

  if (dbus_error_is_set(&error))
  {
    printf("Error connecting to the daemon bus: %s",error.message);
    dbus_error_free(&error);
    return 1;
  }

  dbus_bus_add_match(connection, "type='signal',sender='org.freedesktop.PowerManagement", NULL);
  dbus_connection_add_filter(connection, dbus_filter, loop, NULL);
  dbus_connection_flush(connection);
  
  dbus_connection_setup_with_g_main(connection,NULL);
  
  printf("Starting loop\n");

  g_main_loop_run(loop);

  return 0;
}