Gtkmm & async timer IT & string error

Gtkmm & async timer IT & string error

I get a very special error. If I get timer IT very often. And I call a
function (in call back func), which has a string parameter, GTK doesn't
response any trigger.
Here is examplewindow.h
#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H
#include <iostream>
#include <gtkmm.h>
#include <time.h>
#include <signal.h>
using namespace std;
using namespace Glib;
using namespace Gtk;
class ExampleWindow : public Gtk::Window
{
public:
ExampleWindow();
virtual ~ExampleWindow();
protected:
timer_t asyncTim;
struct itimerspec timerStruct;
//Signal handlers:
void on_button_clicked();
//Child widgets:
Gtk::Box m_VBox;
Gtk::Label m_Label;
Gtk::ButtonBox m_ButtonBox;
Gtk::Button m_Button;
// Gtk::AboutDialog m_Dialog;
};
void func(string message);
void asyncCallback(int i);