diff --git a/src/time_stamp.h b/src/time_stamp.h
index ad9c78a146cf1ee4bca20ea1e92c03134199784a..f0d0eede36cfd156a52d64dc9b386a322c67d784 100644
--- a/src/time_stamp.h
+++ b/src/time_stamp.h
@@ -254,6 +254,8 @@ inline TimeStamp TimeStamp::operator +(const Scalar& dt) const
     return TimeStamp(time_stamp_ + dt);
 }
 
+static const TimeStamp InvalidStamp(-1,-1);
+
 } // namespace wolf
 
 #endif