diff --git a/include/openPMD/auxiliary/Mpi.hpp b/include/openPMD/auxiliary/Mpi.hpp
index 8b552e5571..973137adc3 100644
--- a/include/openPMD/auxiliary/Mpi.hpp
+++ b/include/openPMD/auxiliary/Mpi.hpp
@@ -115,7 +115,7 @@ void runOnRankZero(Mock_MPI_Comm, Functor &&functor)
 }
 
 template <typename T>
-T MPI_Bcast_fromRankZero(Mock_MPI_Comm, T *)
+void MPI_Bcast_fromRankZero(Mock_MPI_Comm, T *)
 {}
 
 #endif