diff --git a/libvips/convolution/conva.c b/libvips/convolution/conva.c
index 2b3a48bd..49aed0aa 100644
--- a/libvips/convolution/conva.c
+++ b/libvips/convolution/conva.c
@@ -79,9 +79,9 @@ $ vips im_max abs.v
  */
 
 /*
- */
 #define DEBUG
 #define VIPS_DEBUG
+ */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>