diff --git a/src/common/utilscmn.cpp b/src/common/utilscmn.cpp
index 205d577d42..268fdd05f1 100644
--- a/src/common/utilscmn.cpp
+++ b/src/common/utilscmn.cpp
@@ -505,7 +505,10 @@ static long wxDoExecuteWithCapture(const wxString& command,
         }
 
     }
-#endif // wxUSE_STREAMS
+#else
+    wxUnusedVar(output);
+    wxUnusedVar(error);
+#endif // wxUSE_STREAMS/!wxUSE_STREAMS
 
     delete process;