GIVFuncInfo* g_function_info_get_vfunc (GIFunctionInfo* info);
Obtain the virtual function associated with this GIFunctionInfo. Only GIFunctionInfo with the flag %GI_FUNCTION_WRAPS_VFUNC has a virtual function set. For other cases, %NULL will be returned.
Free it by calling g_base_info_unref() when done.