g_signal_connect error , gtk 4

[formal carbon]

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[gentle hawk]

//callback function on app activation
void GTKCanvas::activate(GtkApplication *p_app, gpointer p_userData)
{
    this->WindowWidget = gtk_application_window_new(this->m_app);
    gtk_window_set_title(GTK_WINDOW(this->WindowWidget), "test window titles");
    gtk_window_set_default_size(GTK_WINDOW(this->WindowWidget), 1600, 800);
    gtk_window_present(GTK_WINDOW(this->WindowWidget));
}```

void GTKCanvas::create_canvas()
{
    //create gtk application struct and assign address to m_app
    this->m_app = gtk_application_new("testappname", G_APPLICATION_DEFAULT_FLAGS);
    g_signal_connect(this->m_app, "activate", G_CALLBACK(activate), NULL);
}```

    GTKCanvas Canv{};
    Canv.create_canvas();```