#ifndef __SG_CONDITION_HXX
#define __SG_CONDITION_HXX
+#include <set>
#include <simgear/structure/SGReferenced.hxx>
#include <simgear/structure/SGSharedPtr.hxx>
SGCondition ();
virtual ~SGCondition ();
virtual bool test () const = 0;
+ virtual void collectDependentProperties(std::set<const SGPropertyNode*>& props) const { }
};