diff --git a/example/example.cabal b/example/example.cabal
index 7c02a2f..24b5fb8 100644
--- a/example/example.cabal
+++ b/example/example.cabal
@@ -52,7 +52,7 @@ extra-doc-files:    CHANGELOG.md
 -- extra-source-files:
 
 common warnings
-    ghc-options: -Wall
+    ghc-options: -Wall -threaded
 
 executable example
     -- Import common warning flags.