diff -r 2e73456e5f84 -r 3700ac4bd9a3 src/cx/buffer.h
--- a/src/cx/buffer.h	Sun May 01 13:14:31 2022 +0200
+++ b/src/cx/buffer.h	Sun May 01 16:12:13 2022 +0200
@@ -117,12 +117,7 @@
      * The write function used for flushing.
      * If NULL, the flushed content gets discarded.
      */
-    size_t (*flush_func)(
-            void const *,
-            size_t,
-            size_t,
-            void *
-    );
+    cx_write_func flush_func;
 
     /**
      * The target for \c flush_func.