Filtering x events

[Mohith Manoj <mohith manoj skanray com>]

I have an application where I need to intercept keyboard LEFT / RIGHT key presses and translate them to SHIFT+TAB / TAB. I understand that Gdk::Window::add_filter() or gdk_window_add_filter() is my way forward.

So I installed a filter function by calling the above method and I am able to intercept the events right. However I am unable to translate the X event to an equivalent Gdk event.

001 GdkFilterReturn FilterInput(GdkXEvent *xevent,
002                             GdkEvent *event,
003                             gpointer data)
004 {
005   GdkFilterReturn eRet = GDK_FILTER_CONTINUE;
006 
007   {
008     XEvent *pEvent = (XEvent*)xevent;
009 
010     if (2
011         == pEvent->type)
012     {
013       if ((113
014            == pEvent->xkey.keycode)
015           || (114
016               == pEvent->xkey.keycode))
017       {
018         event->key.hardware_keycode = pEvent->xkey.keycode;
019         event->key.keyval = GDK_KEY_Tab;
020         event->key.length = 0;
021         event->key.time = pEvent->xkey.time;
022         event->key.type = GDK_KEY_PRESS;
023 
024         if(113 == pEvent->xkey.keycode)
025         {
026           event->key.state |= GDK_SHIFT_MASK;
027           event->key.keyval = GDK_KEY_ISO_Left_Tab;
028         }
029 
030         eRet = GDK_FILTER_TRANSLATE;
031       }
032     }
033   }
034 
035   return eRet;
036 }

Above code always causes the application to crash when I do LEFT / RIGHT with the following warning.

Gdk-WARNING **: 13:16:43.246: Event with type 8 not holding a GdkDevice. It is most likely synthesized outside Gdk/GTK+

I did quite a bit of search to find examples on translating X events to Gdk events without any leads. Can someone tell me what is missing in my code or point me to some examples where filtering is done?

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