diff --git a/src/unittest/cprintftest.cc b/src/unittest/cprintftest.cc
index 7e6d2f2d46..091d292bc6 100644
--- a/src/unittest/cprintftest.cc
+++ b/src/unittest/cprintftest.cc
@@ -45,7 +45,7 @@ main()
     cprintf("%s\n", foo);
 
     string _bar = "asdfkhasdlkfjhasdlkfhjalksdjfhalksdjhfalksdjfhalksdjhf";
-    int length = 11;
+    const int length = 11;
     char bar[length + 1];
     bar[length] = 0;