+
+/*************
+ * Callbacks *
+ *************/
+simgrid::xbt::signal<void(s4u::Link&)> Link::onCreation;
+simgrid::xbt::signal<void(s4u::Link&)> Link::onDestruction;
+simgrid::xbt::signal<void(s4u::Link&)> Link::onStateChange;
+simgrid::xbt::signal<void(surf::NetworkAction*, s4u::Host* src, s4u::Host* dst)> Link::onCommunicate;
+simgrid::xbt::signal<void(surf::NetworkAction*)> Link::onCommunicationStateChange;