diff --git a/libs/pbd/pbd/configuration_variable.h b/libs/pbd/pbd/configuration_variable.h
index 7af7974229..143f53f218 100644
--- a/libs/pbd/pbd/configuration_variable.h
+++ b/libs/pbd/pbd/configuration_variable.h
@@ -90,7 +90,7 @@ class /*LIBPBD_API*/ ConfigVariable : public ConfigVariableBase
 };
 
 /** Specialisation of ConfigVariable to deal with float (-inf etc) */
-template<> void
+template<> LIBPBD_API void
 ConfigVariable<float>::set_from_string (std::string const & s);
 
 /** Specialisation of ConfigVariable for std::string to cope with whitespace properly */