diff --git a/magick/module.c b/magick/module.c
index 59d5191..d441c8c 100644
--- a/magick/module.c
+++ b/magick/module.c
@@ -1639,7 +1639,7 @@
 #else
   {
     extern size_t
-      analyzeImage(Image **,const int,char **,ExceptionInfo *);
+      analyzeImage(Image **,const int,const char **,ExceptionInfo *);
 
     ImageFilterHandler
       *image_filter;