gtk_window_fullscreen problem

[Alexander Kuleshov <kuleshovmail gmail com>]

Hello,

I need in full screen window functional in my gtk+ application. I try
to use gtk_window_fullscreen(GtkWindow* Window):

I have function:
static void
full_screen(MainWin *mw)
{
    gtk_window_fullscreen((GtkWindow*)mw);
}

When i try to call this function i see error:
Gtk-CRITICAL **: gtk_window_fullscreen: assertion `GTK_IS_WINDOW
(window)' failed

Where MainWin:
typedef struct _MainWin MainWin;

typedef struct _MainWin
{
    GtkWindow parent;
    GtkWidget* scroll;
    GtkWidget* box;
    GtkWidget *toolbar;
    gboolean full_screen;
};

What's wrong?

Thank you