diff --git a/gtk/gtkmain.c b/gtk/gtkmain.c
index 11aee08..336ccc4 100644
--- a/gtk/gtkmain.c
+++ b/gtk/gtkmain.c
@@ -847,7 +847,7 @@ gtk_init_with_args (int            *argc,
 		    char         ***argv,
 		    char           *parameter_string,  
 		    GOptionEntry   *entries,
-		    char           *translation_domain,
+		    const char     *translation_domain,
 		    GError        **error)
 {
   GOptionContext *context;
diff --git a/gtk/gtkmain.h b/gtk/gtkmain.h
index 975057e..3162e96 100644
--- a/gtk/gtkmain.h
+++ b/gtk/gtkmain.h
@@ -101,7 +101,7 @@ gboolean gtk_init_with_args       (int            *argc,
 				   char         ***argv,
 				   char           *parameter_string,
 				   GOptionEntry   *entries,
-				   char           *translation_domain,
+				   const char     *translation_domain,
 				   GError        **error);
 
 GOptionGroup *gtk_get_option_group (gboolean open_default_display);
