1 files changed, 6 insertions, 4 deletions
diff --git a/extern/ceres/internal/ceres/single_linkage_clustering.h b/extern/ceres/internal/ceres/single_linkage_clustering.h
index ccd6f8ea37d..e891a9eec0a 100644
--- a/extern/ceres/internal/ceres/single_linkage_clustering.h
+++ b/extern/ceres/internal/ceres/single_linkage_clustering.h
@@ -32,7 +32,9 @@
 #define CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_
 
 #include <unordered_map>
+
 #include "ceres/graph.h"
+#include "ceres/internal/port.h"
 
 namespace ceres {
 namespace internal {
@@ -53,10 +55,10 @@ struct SingleLinkageClusteringOptions {
 //
 // The return value of this function is the number of clusters
 // identified by the algorithm.
-int ComputeSingleLinkageClustering(
-    const SingleLinkageClusteringOptions& options,
-    const WeightedGraph<int>& graph,
-    std::unordered_map<int, int>* membership);
+int CERES_EXPORT_INTERNAL
+ComputeSingleLinkageClustering(const SingleLinkageClusteringOptions& options,
+                               const WeightedGraph<int>& graph,
+                               std::unordered_map<int, int>* membership);
 
 }  // namespace internal
 }  // namespace ceres