+
+namespace s4u {
+class Activity;
+
+class Actor;
+/** Smart pointer to a simgrid::s4u::Actor */
+typedef boost::intrusive_ptr<Actor> ActorPtr;
+XBT_PUBLIC void intrusive_ptr_release(Actor* actor);
+XBT_PUBLIC void intrusive_ptr_add_ref(Actor* actor);
+
+class Barrier;
+
+class Comm;
+/** Smart pointer to a simgrid::s4u::Comm */
+typedef boost::intrusive_ptr<Comm> CommPtr;
+XBT_PUBLIC void intrusive_ptr_release(Comm* c);
+XBT_PUBLIC void intrusive_ptr_add_ref(Comm* c);
+
+class ConditionVariable;
+/** Smart pointer to a simgrid::s4u::ConditionVariable */
+typedef boost::intrusive_ptr<ConditionVariable> ConditionVariablePtr;
+XBT_PUBLIC void intrusive_ptr_release(ConditionVariable* c);
+XBT_PUBLIC void intrusive_ptr_add_ref(ConditionVariable* c);
+
+class Engine;
+
+class Exec;
+/** Smart pointer to a simgrid::s4u::Exec */
+typedef boost::intrusive_ptr<Exec> ExecPtr;
+XBT_PUBLIC void intrusive_ptr_release(Exec* e);
+XBT_PUBLIC void intrusive_ptr_add_ref(Exec* e);
+
+class Host;
+
+class Io;
+/** Smart pointer to a simgrid::s4u::Io */
+typedef boost::intrusive_ptr<Io> IoPtr;
+XBT_PUBLIC void intrusive_ptr_release(Io* i);
+XBT_PUBLIC void intrusive_ptr_add_ref(Io* i);
+
+class Link;
+
+class Mailbox;
+/** Smart pointer to a simgrid::s4u::Mailbox */
+typedef boost::intrusive_ptr<Mailbox> MailboxPtr;
+XBT_PUBLIC void intrusive_ptr_release(Mailbox* m);
+XBT_PUBLIC void intrusive_ptr_add_ref(Mailbox* m);
+
+class Mutex;
+XBT_PUBLIC void intrusive_ptr_release(Mutex* m);
+XBT_PUBLIC void intrusive_ptr_add_ref(Mutex* m);
+/** Smart pointer to a simgrid::s4u::Mutex */
+typedef boost::intrusive_ptr<Mutex> MutexPtr;
+
+class NetZone;
+class VirtualMachine;
+class File;
+class Storage;
+} // namespace s4u
+
+namespace config {
+template <class T> class Flag;
+}
+
+namespace kernel {
+class EngineImpl;
+namespace actor {
+class ActorImpl;
+typedef boost::intrusive_ptr<ActorImpl> ActorImplPtr;
+} // namespace actor
+
+namespace activity {
+ class ActivityImpl;
+ typedef boost::intrusive_ptr<ActivityImpl> ActivityImplPtr;
+ XBT_PUBLIC void intrusive_ptr_add_ref(ActivityImpl* activity);
+ XBT_PUBLIC void intrusive_ptr_release(ActivityImpl* activity);
+
+ class ConditionVariableImpl;
+
+ class CommImpl;
+ typedef boost::intrusive_ptr<CommImpl> CommImplPtr;
+ class ExecImpl;
+ typedef boost::intrusive_ptr<ExecImpl> ExecImplPtr;
+ class IoImpl;
+ typedef boost::intrusive_ptr<IoImpl> IoImplPtr;
+ class MutexImpl;
+ typedef boost::intrusive_ptr<MutexImpl> MutexImplPtr;
+ class RawImpl;
+ typedef boost::intrusive_ptr<RawImpl> RawImplPtr;
+ class SleepImpl;
+ typedef boost::intrusive_ptr<SleepImpl> SleepImplPtr;
+
+ class MailboxImpl;
+}
+namespace context {
+class Context;
+class ContextFactory;
+} // namespace context
+namespace lmm {
+class Element;
+class Variable;
+class Constraint;
+class ConstraintLight;
+class System;
+}
+namespace resource {
+class Action;
+class Model;
+class Resource;
+class NetworkModel;
+class TraceEvent;
+class LinkImpl;
+class NetworkAction;
+}
+namespace routing {
+class ClusterCreationArgs;
+class LinkCreationArgs;
+class NetPoint;
+class NetZoneImpl;
+class RouteCreationArgs;
+}
+} // namespace kernel
+namespace simix {