diff --git a/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Error_code.h b/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Error_code.h
index 7592c4c170d..e91ab8d13d1 100644
--- a/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Error_code.h
+++ b/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/Error_code.h
@@ -49,7 +49,7 @@ enum Error_code
 /// \brief Get the message corresponding to an error code.
 /// \param error_code The code returned by `parameterize()`
 /// \return The string describing the error code.
-const char* get_error_message(int error_code)
+inline const char* get_error_message(int error_code)
 {
   // Messages corresponding to Error_code list above. Must be kept in sync!
   static const char* error_message[ERROR_WRONG_PARAMETER+1] = {