diff -r 08539b8273fa -r 4fbfac557df8 src/cx/allocator.h
--- a/src/cx/allocator.h	Mon Apr 18 16:56:29 2022 +0200
+++ b/src/cx/allocator.h	Mon Apr 18 17:26:21 2022 +0200
@@ -117,6 +117,57 @@
 typedef void (*cx_destructor_func)(void *memory) __attribute__((__nonnull__));
 
 /**
+ * Function pointer type for destructor functions.
+ *
+ * A destructor function deallocates possible contents and MAY free the memory
+ * pointed to by \p memory. Read the documentation of the respective function
+ * pointer to learn if a destructor SHALL, MAY, or MUST NOT free the memory in that
+ * particular implementation.
+ *
+ * @param data an optional pointer to custom data
+ * @param memory a pointer to the object to destruct
+  */
+typedef void (*cx_destructor_func2)(
+        void *data,
+        void *memory
+) __attribute__((__nonnull__(2)));
+
+/**
+ * Structure holding an advanced destructor function and the desired payload.
+ * Invocations of func should use data as first argument.
+ */
+typedef struct {
+    /**
+     * A pointer to the data that SHALL be used to invoke func.
+     */
+    void *data;
+    /**
+     * A pointer to the function to invoke.
+     */
+    cx_destructor_func2 func;
+} cx_advanced_destructor;
+
+/**
+ * Specifies the type of destructor to use.
+ */
+enum cx_destructor_type {
+    /**
+     * Do not use a destructor function.
+     */
+    CX_DESTRUCTOR_NONE,
+    /**
+     * Use a simple destructor.
+     * @see cx_destructor_func
+     */
+    CX_DESTRUCTOR_SIMPLE,
+    /**
+     * Use an advanced destructor.
+     * @see cx_advanced_destructor
+     */
+    CX_DESTRUCTOR_ADVANCED
+};
+
+/**
  * Allocate \p n bytes of memory.
  *
  * @param allocator the allocator