diff --git a/awkward-cpp/include/awkward/util.h b/awkward-cpp/include/awkward/util.h
index 91a4d770a0..b6ff5c7561 100644
--- a/awkward-cpp/include/awkward/util.h
+++ b/awkward-cpp/include/awkward/util.h
@@ -47,7 +47,7 @@ namespace awkward {
     dtype_to_name(dtype dt);
 
     /// @brief Convert a dtype enum into a NumPy format string.
-    const std::string
+    EXPORT_SYMBOL const std::string
     dtype_to_format(dtype dt, const std::string& format = "");
 
     /// @brief Puts quotation marks around a string and escapes the appropriate