diff --git a/src/tl/tl/tlOptional.cc b/src/tl/tl/tlOptional.cc
index ba2774439..d7ee370b2 100644
--- a/src/tl/tl/tlOptional.cc
+++ b/src/tl/tl/tlOptional.cc
@@ -25,6 +25,6 @@
 namespace tl
 {
 
-extern const nullopt_t nullopt = nullopt_t ();
+const nullopt_t nullopt = nullopt_t ();
 
 } // namespace tl
diff --git a/src/tl/tl/tlOptional.h b/src/tl/tl/tlOptional.h
index c30fa6679..3893d6ac0 100644
--- a/src/tl/tl/tlOptional.h
+++ b/src/tl/tl/tlOptional.h
@@ -34,7 +34,7 @@ namespace tl
 
 struct nullopt_t {};
 
-extern const nullopt_t nullopt;
+extern TL_PUBLIC const nullopt_t nullopt;
 
 /**
  *  @brief Poor man's partial implementation of C++17's std::optional