xbt::signal<void(bool symmetrical, kernel::routing::NetPoint* src, kernel::routing::NetPoint* dst,
kernel::routing::NetPoint* gw_src, kernel::routing::NetPoint* gw_dst,
xbt::signal<void(bool symmetrical, kernel::routing::NetPoint* src, kernel::routing::NetPoint* dst,
kernel::routing::NetPoint* gw_src, kernel::routing::NetPoint* gw_dst,
-xbt::signal<void(NetZone&)> NetZone::on_creation;
-xbt::signal<void(NetZone&)> NetZone::on_seal;
+xbt::signal<void(NetZone const&)> NetZone::on_creation;
+xbt::signal<void(NetZone const&)> NetZone::on_seal;