diff --git a/internal/ceres/sparse_matrix.h b/internal/ceres/sparse_matrix.h
index 074d847..b57f108 100644
--- a/internal/ceres/sparse_matrix.h
+++ b/internal/ceres/sparse_matrix.h
@@ -34,8 +34,10 @@
 #define CERES_INTERNAL_SPARSE_MATRIX_H_
 
 #include <cstdio>
-#include "ceres/linear_operator.h"
+
 #include "ceres/internal/eigen.h"
+#include "ceres/internal/port.h"
+#include "ceres/linear_operator.h"
 #include "ceres/types.h"
 
 namespace ceres {
@@ -62,7 +64,7 @@
 // matrix type dependent and we are at this stage unable to come up
 // with an efficient high level interface that spans multiple sparse
 // matrix types.
-class SparseMatrix : public LinearOperator {
+class CERES_EXPORT_INTERNAL SparseMatrix : public LinearOperator {
  public:
   virtual ~SparseMatrix();