namespace s4u {
class Actor;
+XBT_PUBLIC(void) intrusive_ptr_release(Actor* actor);
+XBT_PUBLIC(void) intrusive_ptr_add_ref(Actor* actor);
using ActorPtr = boost::intrusive_ptr<Actor>;
class Activity;
using MailboxPtr = boost::intrusive_ptr<Mailbox>;
class Mutex;
class NetZone;
+class VirtualMachine;
class File;
class Storage;