diff -r 47e0f2237a94 -r 67e078518935 src/cx/buffer.h
--- a/src/cx/buffer.h	Sun May 01 10:39:13 2022 +0200
+++ b/src/cx/buffer.h	Sun May 01 11:44:23 2022 +0200
@@ -125,6 +125,11 @@
     );
 
     /**
+     * The target for \c flush_func.
+     */
+    void *flush_target;
+
+    /**
      * Flag register for buffer features.
      * @see #CX_BUFFER_DEFAULT
      * @see #CX_BUFFER_FREE_CONTENTS