Fetching symbols information with XKBlib

Hello,

my X server is XKB-enabled, and keyboard is configured to suport Russian
input:

Section "InputDevice"
	Identifier  "Keyboard0"
	Driver      "kbd"
	Option	    "XkbModel" "pc104"
	Option	    "XkbLayout" "ru(phonetic)"
	Option	    "XkbSymbols" "en_US(pc104)+ru(phonetic)+group(shift_toggle)"
	Option	    "XkbOptions" "grp:shift_toggle"
EndSection

With this configuration, Shift-Shift toggles from English to Russian, and my app
needs to know which symbols are current. I'm trying to use XKBlib calls to
obtain the state:

...
XkbEvent xkbev;
...
display = XkbOpenDisplay(...);
XkbSelectEvents (display, XkbUseCoreKbd,
                  XkbStateNotifyMask, XkbStateNotifyMask);
...
while (1) {
         XNextEvent (display, &xkbev.core);
	if (xkbev.state.changed == (XkbGroupStateMask |
                                     XkbGroupLockMask |
                                     XkbCompatStateMask |
                                     XkbCompatLookupModsMask)) {
         /* Symbols switched, need to ask about current ones */
         }
}

But I can't find a way to ask about current symbols. I just want to receive
short description like 'ru' or 'en' (or any other information which may be
used to identify current symbols) - is there a way to get it ?

Thanks,
Dmitry