diff -ur qt-everywhere-opensource-src-4.6.3/src/gui/kernel/qguieventdispatcher_glib.cpp qt-everywhere-opensource-src-4.6.3-glib_eventloop_nullcheck/src/gui/kernel/qguieventdispatcher_glib.cpp

--- qt-everywhere-opensource-src-4.6.3/src/gui/kernel/qguieventdispatcher_glib.cpp	2010-06-02 04:03:15.000000000 +0200

+++ qt-everywhere-opensource-src-4.6.3-glib_eventloop_nullcheck/src/gui/kernel/qguieventdispatcher_glib.cpp	2010-12-08 22:22:38.000000000 +0100

@@ -76,7 +76,7 @@

     GX11EventSource *source = reinterpret_cast<GX11EventSource *>(s);

     return (XEventsQueued(X11->display, QueuedAfterFlush)

             || (!(source->flags & QEventLoop::ExcludeUserInputEvents)

-                && !source->d->queuedUserInputEvents.isEmpty()));

+                && source->d && !source->d->queuedUserInputEvents.isEmpty()));

 }

 static gboolean x11EventSourceCheck(GSource *s)

@@ -84,7 +84,7 @@

     GX11EventSource *source = reinterpret_cast<GX11EventSource *>(s);

     return (XEventsQueued(X11->display, QueuedAfterFlush)

             || (!(source->flags & QEventLoop::ExcludeUserInputEvents)

-                && !source->d->queuedUserInputEvents.isEmpty()));

+                && source->d && !source->d->queuedUserInputEvents.isEmpty()));

 }

 static gboolean x11EventSourceDispatch(GSource *s, GSourceFunc callback, gpointer user_data)

@@ -95,7 +95,7 @@

     do {

         XEvent event;

         if (!(source->flags & QEventLoop::ExcludeUserInputEvents)

-            && !source->d->queuedUserInputEvents.isEmpty()) {

+            && source->d && !source->d->queuedUserInputEvents.isEmpty()) {

             // process a pending user input event

             event = source->d->queuedUserInputEvents.takeFirst();

         } else if (XEventsQueued(X11->display, QueuedAlready)) {

@@ -112,7 +112,8 @@

                 case XKeyRelease:

                 case EnterNotify:

                 case LeaveNotify:

-                    source->d->queuedUserInputEvents.append(event);

+                    if (source->d)

+                        source->d->queuedUserInputEvents.append(event);

                     continue;

                 case ClientMessage:

@@ -127,7 +128,8 @@

                             break;

                         }

                     }

-                    source->d->queuedUserInputEvents.append(event);

+                    if (source->d)

+                        source->d->queuedUserInputEvents.append(event);

                     continue;

                 default:

@@ -140,7 +142,7 @@

         }

         // send through event filter

-        if (source->q->filterEvent(&event))

+        if (source->q && source->q->filterEvent(&event))

             continue;

         if (qApp->x11ProcessEvent(&event) == 1)

@@ -152,7 +154,8 @@

  out:

-    source->d->runTimersOnceWithNormalPriority();

+    if (source->d)

+        source->d->runTimersOnceWithNormalPriority();

     if (callback)

         callback(user_data);