Gtk/C++ Chronometer

Question

I'm doing a game that uses a chronometer. The game is written in C++ and I'm also using glade and GTK3.0

My problem is that when I start the game the chronometer doesn't work as it should..

I have created a file time.h with this code inside:

---

struct aTimer
{
    bool running = false;   
    int hour_expired = 0;
    int min_expired = 59;
    int sec_expired = 50;
};

void start_time(aTimer *&t)
{
    t->running = true;
}

void reset_time(aTimer *&t)
{
    t->running = false;
    t->sec_expired = 0;
    t->min_expired = 0;
    t->hour_expired = 0;
}

---

In my main file, I include it and also declare a new chronometer like this:

void start_time(aTimer *&);
void reset_time(aTimer *&);

aTimer *tempo = new aTimer;

Now, in my game, I have 2 windows, when i press play from the first window, the second window becomes visible and I hide the first one. When the second one is closed, the first becomes visible and the second invisible.. When the first window is closed, the application is closed.

In the struct, the bool running is false, because my idea was to make it true when you actually play the game (that is when you have the second window visible) and not at the start of the application..

So I've done this in the main file:

---

void start_game()
{
    start_time(tempo);
}

gboolean update_time()
{
    if (tempo->running)
    {
        if (tempo->sec_expired == 60)
        {
            tempo->sec_expired = 0;
            (tempo->min_expired)++;
            if (tempo->min_expired == 60)
            {
                tempo->min_expired = 0;
                (tempo->hour_expired)++;
            }
        }

        ostringstream oss;  
        GtkLabel *time = GTK_LABEL(gtk_builder_get_object(builder, "lblSec"));  
        oss<<(tempo->sec_expired)++;
        gtk_label_set_text(time, oss.str().c_str());
        oss.str("");
        oss.clear();
        time = GTK_LABEL(gtk_builder_get_object(builder, "lblMin"));
        oss<<tempo->min_expired<<":";
        gtk_label_set_text(time, oss.str().c_str());
        oss.str("");
        oss.clear();
        time = GTK_LABEL(gtk_builder_get_object(builder, "lblHour"));
        oss<<tempo->hour_expired<<":";
        gtk_label_set_text(time, oss.str().c_str());
        oss.str("");
        oss.clear();
    }
return tempo->running;
}

---

and in the main function of the main file i have also:

g_timeout_add_seconds(1, GSourceFunc(update_time), NULL);

If I start the application with the bool running = false, it won't work at all If I start it the running = true, then it does work when i start the application, but as i come back to the "menu" and want to play another game, it won't start again.. The new time will just be the old time and won't increment anymore I don't understand why though... Can someone help me? Thank you

********************UPDATE************************

I tried the GTimer "option" as @José Fonte suggested but still can't come ahead..

This is an example that i tried..

#include <iostream>
#include <glib.h>
#include <sstream>
#include <gtk/gtk.h>

static GtkBuilder *builder;

using namespace std;

GTimer *timing;

bool start = false;

extern "C" void btnStartPause_click(GtkButton *button)
{
    if (!start)
    {
        timing = g_timer_new();
        start = true;
    }
    else
    {
        g_timer_stop(timing);
        start = false;
    }
}

gboolean update_time()
{
    if (start)
    {
        gulong *micro;
        double sec;
        sec = g_timer_elapsed(timing, micro);
        ostringstream oss;
        GtkLabel *time = GTK_LABEL(gtk_builder_get_object(builder, "lblSec"));  
        oss<<(sec)++;
        gtk_label_set_text(time, oss.str().c_str());
        oss.str("");
        oss.clear();
    }
    return start;
}

int main(int argc, char *argv[])
{
    gtk_init(&argc, &argv);

    builder = gtk_builder_new();

    gtk_builder_add_from_file(builder,"glade.glade", NULL);

    gtk_builder_connect_signals(builder, NULL); 

    // timing       
    g_timeout_add_seconds(1, GSourceFunc(update_time), NULL);

    gtk_main();

    return 0;
}

The problem again is.. I wanna start the timing when i click the btnStartPause button (not when i start the application), so i want it to start in the btnClick function.. But it seems like that the application tries instantly to do the gboolean update_time() function but since at the start of the application the boolean start is false, it just won't do the code, but when i click the button, so that the boolean start becomes true, it doesn't try again the gboolean update_time(), like it tried at the start of the application, and won't try it anymore.. I don't understand this..