diff --git a/libvips/iofuncs/im_open.c b/libvips/iofuncs/im_open.c
index df90513b..15666245 100644
--- a/libvips/iofuncs/im_open.c
+++ b/libvips/iofuncs/im_open.c
@@ -127,8 +127,8 @@ Modified:
  */
 
 /*
- */
 #define DEBUG
+ */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>