diff --git a/config.h.cmake b/config.h.cmake
index 269acc4..a675bad 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -32,7 +32,7 @@
 
 // kcalc
 
-@SIZEOF_UNSIGNED_LONG_CODE@
+#cmakedefine SIZEOF_UNSIGNED_LONG @SIZEOF_UNSIGNED_LONG@
 
 #if !defined( HAVE_STDLIB_H )
 #cmakedefine HAVE_STDLIB_H