diff --git a/callouts/callout_test.cpp b/callouts/callout_test.cpp
index 729bbf5..fd2cf17 100644
--- a/callouts/callout_test.cpp
+++ b/callouts/callout_test.cpp
@@ -22,7 +22,7 @@
                           TestCallout::CALLOUT_ERRNO_TEST(0),
                           TestCallout::CALLOUT_DEVICE_PATH_TEST(argv[1]));
     }
-    catch (TestCallout& e)
+    catch (const TestCallout& e)
     {
         commit(e.name());
     }