1 files changed, 2 insertions, 1 deletions
diff --git a/extern/ceres/internal/ceres/linear_operator.h b/extern/ceres/internal/ceres/linear_operator.h
index 6463fb5089a..9c59fc39c13 100644
--- a/extern/ceres/internal/ceres/linear_operator.h
+++ b/extern/ceres/internal/ceres/linear_operator.h
@@ -33,6 +33,7 @@
 #ifndef CERES_INTERNAL_LINEAR_OPERATOR_H_
 #define CERES_INTERNAL_LINEAR_OPERATOR_H_
 
+#include "ceres/internal/port.h"
 #include "ceres/types.h"
 
 namespace ceres {
@@ -40,7 +41,7 @@ namespace internal {
 
 // This is an abstract base class for linear operators. It supports
 // access to size information and left and right multiply operators.
-class LinearOperator {
+class CERES_EXPORT_INTERNAL LinearOperator {
  public:
   virtual ~LinearOperator();