diff --git a/unsupported/Eigen/src/Splines/SplineFwd.h b/unsupported/Eigen/src/Splines/SplineFwd.h
index 5d9bfacf8..9ea23a9a1 100644
--- a/unsupported/Eigen/src/Splines/SplineFwd.h
+++ b/unsupported/Eigen/src/Splines/SplineFwd.h
@@ -64,6 +64,8 @@ namespace Eigen
     {
       enum { OrderAtCompileTime = _Degree==Dynamic ? Dynamic : _Degree+1 /*!< The spline curve's order at compile-time. */ };
       enum { NumOfDerivativesAtCompileTime = _DerivativeOrder==Dynamic ? Dynamic : _DerivativeOrder+1 /*!< The number of derivatives defined for the current spline. */ };
+      
+      enum { DerivativeMemoryLayout = _Dim==1 ? RowMajor : ColMajor /*!< The derivative type's memory layout. */ };
 
       /** \brief The data type used to store the values of the basis function derivatives. */
       typedef Array<_Scalar,Dynamic,Dynamic,RowMajor,NumOfDerivativesAtCompileTime,OrderAtCompileTime> BasisDerivativeType;