diff --git a/gdk-pixbuf/ChangeLog b/gdk-pixbuf/ChangeLog
index b18e30f386..87120f9485 100644
--- a/gdk-pixbuf/ChangeLog
+++ b/gdk-pixbuf/ChangeLog
@@ -1,5 +1,7 @@
 2005-08-30  Matthias Clasen  <mclasen@redhat.com>
 
+	* gdk-pixbuf-io.c (format_check): Make this work again.
+
 	* io-png.c (png_save_to_callback_write_func): Add a cast
 	to avoid compiler warnings.
 
diff --git a/gdk-pixbuf/gdk-pixbuf-io.c b/gdk-pixbuf/gdk-pixbuf-io.c
index b330ea5efa..56dfefe627 100644
--- a/gdk-pixbuf/gdk-pixbuf-io.c
+++ b/gdk-pixbuf/gdk-pixbuf-io.c
@@ -52,16 +52,17 @@ format_check (GdkPixbufModule *module, guchar *buffer, int size)
 	gchar m;
 	GdkPixbufModulePattern *pattern;
 	gboolean anchored;
-	gchar *prefix, *mask;
+	guchar *prefix;
+	gchar *mask;
 
 	for (pattern = module->info->signature; pattern->prefix; pattern++) {
 		if (pattern->mask && pattern->mask[0] == '*') {
-			prefix = pattern->prefix + 1;
+			prefix = (guchar *)pattern->prefix + 1;
 			mask = pattern->mask + 1;
 			anchored = FALSE;
 		}
 		else {
-			prefix = pattern->prefix;
+			prefix = (guchar *)pattern->prefix;
 			mask = pattern->mask;
 			anchored = TRUE;
 		}