The GtkItemFactoryEntry struct callback is of type GtkItemFactoryCallbacks

(aka void ()(void)) but is initialised with GtkItemFactoryCallback1 types

(aka void ()(void , guint,  GtkWidget )).
This is coherent with the gtk-2 documentation:


gtk_item_factory_create_items(..., GtkItemFactoryEntry *entries,...)

 entries : an array of GtkItemFactoryEntrys whose callback members must by of

 type GtkItemFactoryCallback1

But, under gcc-14, the implicit cast from GtkItemFactoryCallback1 to

GtkItemFactoryCallback triggers an incompatible-pointer-types error (See [gcc-doc]).
An exemple of this error:
pidgin/gtkconv.c:3096:66: error: initialization of 'void (*)(void)' from incompatible pointer type 'void (*)(void *, guint,  GtkWidget *)' {aka 'void (*)(void *, unsigned int,  struct _GtkWidget *)'} [-Wincompatible-pointer-types]
 3096 |         { N_("/Conversation/New Instant _Message..."), "<CTL>M", menu_new_conv_cb,
      |                                                                  ^~~~~~~~~~~~~~~~
pidgin/gtkconv.c:3096:66: note: (near initialization for 'menu_items[1].callback')

To fix this, explicitely cast to GtkItemFactoryCallback where needed.

Built with gcc-14, started and clicked on some affected menus