Place popup menu below widget GTK - c

Question

I am having some trouble placing my popup menu where I want in GTK(along the same y axis as my button so it seems to dropdown from the button).
I got it working when I was coding a similar thing in win32 but for the life of me I cannot get this thing to draw where I want!
I've done my research and I know what (I think) should work and that is when I make the call to
gtk_menu_popup()
I should pass it in a function pointer to a method for placing the popup (link to the method specification - http://developer.gnome.org/gtk/2.24/GtkMenu.html#GtkMenuPositionFunc )
But i'm a bit rubbish with function pointers ( I have the Kernighan and ritchie book beside as I speak) but I'm pretty sure I'm doing it right.
Heres my attempt at the method :
void set_position(GtkMenu *menu,gint *x,gint *y,gboolean push_in,gpointer user_data)
{
printf("Help!\n";
GtkWidget *originButton = (GtkWidget *) gtk_object_get_data(GTK_OBJECT(menu),"button");
gdk_window_get_position(originButton->window,x,y);
//now I realise this will place it at the top of the widget but thats acceptable for now, I just want the method to be called!
}
I call it from the button handler by doing this :
static gboolean handler (GtkWidget *widget,GdkEvent *event)
{
GdkEventButton *bevent = (GdkEventButton *) event;
gtk_menu_popup(GTK_MENU(widget),NULL,NULL,set_position,bevent->button,bevent->button,bevent->time);
}
But when I compile this it says its not a GtkMenuPositionFunc, so I just cast it (dont know if thats right though).
The problem is that I dont think my method is getting called because it never prints out help :( plus it still spawns the menu wherever I click (probably due to it not calling the method or whatever it should be doing).
Any help/ideas would be greatly received :) thanks :)

Answer 1

I had the same problem earlier. I used the following code.
static void
set_position(GtkMenu *menu, gint *x, gint *y, gboolean *push_in, gpointer user_data)
{
GtkWidget *button = GTK_BUTTON(user_data);
gdk_window_get_origin(button->window, x, y);
*x += button->allocation.x;
*y += (button->allocation.y + (button->allocation.height));
}
static void
handler(GtkWidget *menu, GtkWidget *button)
{
GtkRequisition requisition;
gtk_widget_size_request(menu, &requisition);
if (button->allocation.width > requisition.width)
gtk_widget_set_size_request(menu, button->allocation.width, -1);
gtk_menu_popup(GTK_MENU (menu),
NULL, NULL,
(GtkMenuPositionFunc) set_position, button,
0, gtk_get_current_event_time());
}

Answer 2

Okay, thanks very much to Pfeiffer for his sample code. I had to make some changes to it because I was getting compiler errors (i have Werror on though).
In the set poisition method I ended up casting to a GTK_WIDGET instead of a GTK_BUTTON becauses thats what it was expecting
So my new set position method looked like :
static void set_position(GtkMenu *menu, gint *x, gint *y, gboolean *push_in, gpointer user_data) {
GtkWidget *button = GTK_WIDGET(user_data);
gdk_window_get_origin(button->window, x, y);
*x += button->allocation.x;
*y += (button->allocation.y + (button->allocation.height));
}
And as I couldn't figure out how to connect and pass the two widgets that Pfeiffer was passing I have this currently :
static gboolean handler(GtkWidget *widget, gpointer data) {
gtk_menu_popup(GTK_MENU(data), NULL, NULL,(GtkMenuPositionFunc)set_position,widget,(guint)widget, gtk_get_current_event_time());
return TRUE;
}
Also had to cast widget to a (guint) otherwise I got a compiler error about the 6th parameter :)
I will probably end up putting more in this method but this is the bare minimum I needed to get it to work.
That is connected using the normal gtk_signal_connect method
gtk_signal_connect(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(handler), GTK_OBJECT(menu));
where button and menu are GtkButton and GtkMenu instances I was using previously :)
Full credit goes to Pfeiffer for the answer, i'm just showing what worked for me :)
Thanks and hope this helps someone :)