Fix data type casting when setting up menus on Windows.

 src/w32menu.c (add_menu_item): Cast to UINT_PTR when assigning
 info.dwItemData.  Fixes crashes on 64-bit Windows.  Suggested by
 Fabrice Popineau <fabrice.popineau@supelec.fr>.

2 files changed, 14 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ed0ea6d3a17..e120edab056 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2012-07-21  Eli Zaretskii  <eliz@gnu.org>
+
+        * w32menu.c (add_menu_item): Cast to UINT_PTR when assigning
+        info.dwItemData.  Fixes crashes on 64-bit Windows.  Suggested by
+        Fabrice Popineau <fabrice.popineau@supelec.fr>.
+
 2012-07-21  Jan Djärv  <jan.h.d@swipnet.se>
 
         * nsterm.m (accessibilityAttributeValue): New function. (Bug#11134).
diff --git a/src/w32menu.c b/src/w32menu.c
index 24dc9d79192..a5f4c3881b5 100644
--- a/src/w32menu.c
+++ b/src/w32menu.c
@@ -1533,7 +1533,14 @@ add_menu_item (HMENU menu, widget_value *wv, HMENU item)
              until it is ready to be displayed, since GC can happen while
              menus are active.  */
           if (!NILP (wv->help))
-            info.dwItemData = (DWORD) XLI (wv->help);
+            {
+              /* As of Jul-2012, w32api headers say that dwItemData
+                 has DWORD type, but that's a bug: it should actually
+                 be UINT_PTR, which is correct for 32-bit and 64-bit
+                 Windows alike.  MSVC headers get it right; hopefully,
+                 MinGW headers will, too.  */
+              info.dwItemData = (UINT_PTR) XLI (wv->help);
+            }
           if (wv->button_type == BUTTON_TYPE_RADIO)
             {
               /* CheckMenuRadioItem allows us to differentiate TOGGLE and