diff --git a/sanei/sanei_pa4s2.c b/sanei/sanei_pa4s2.c
index b98245b43..d74fc65e6 100644
--- a/sanei/sanei_pa4s2.c
+++ b/sanei/sanei_pa4s2.c
@@ -2050,7 +2050,7 @@ sanei_pa4s2_options (u_int * options, int set)
 
 }
 
-char **
+const char **
 sanei_pa4s2_devices()
 {
   TEST_DBG_INIT ();