diff --git a/exile.h b/exile.h
index 66895c3..a79bd10 100644
--- a/exile.h
+++ b/exile.h
@@ -247,7 +247,7 @@ struct syscall_vow_map
 
 struct str_to_vow_map
 {
-	char *str;
+	const char *str;
 	uint64_t value;
 };