diff -r 3eeadf666d6b -r 56c62780582e src/hash_map.c
--- a/src/hash_map.c	Mon Feb 20 19:55:42 2023 +0100
+++ b/src/hash_map.c	Thu Feb 23 18:58:15 2023 +0100
@@ -30,6 +30,17 @@
 #include "cx/hash_map.h"
 #include "cx/utils.h"
 
+struct cx_hash_map_element_s {
+    /** A pointer to the next element in the current bucket. */
+    struct cx_hash_map_element_s *next;
+
+    /** The corresponding key. */
+    CxHashKey key;
+
+    /** The value data. */
+    char data[];
+};
+
 static void cx_hash_map_clear(struct cx_map_s *map) {
     struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
     cx_for_n(i, hash_map->bucket_count) {
@@ -89,17 +100,27 @@
     if (elm != NULL && elm->key.hash == hash && elm->key.len == key.len &&
         memcmp(elm->key.data.obj, key.data.obj, key.len) == 0) {
         // overwrite existing element
-        elm->data = value;
+        if (map->store_pointers) {
+            memcpy(elm->data, &value, sizeof(void *));
+        } else {
+            memcpy(elm->data, value, map->itemsize);
+        }
     } else {
         // allocate new element
-        struct cx_hash_map_element_s *e = cxMalloc(allocator, sizeof(struct cx_hash_map_element_s));
+        struct cx_hash_map_element_s *e = cxMalloc(
+                allocator,
+                sizeof(struct cx_hash_map_element_s) + map->itemsize
+        );
         if (e == NULL) {
             return -1;
         }
 
         // write the value
-        // TODO: depending on future map features, we may want to copy here
-        e->data = value;
+        if (map->store_pointers) {
+            memcpy(e->data, &value, sizeof(void *));
+        } else {
+            memcpy(e->data, value, map->itemsize);
+        }
 
         // copy the key
         void *kd = cxMalloc(allocator, key.len);
@@ -151,7 +172,7 @@
  * @param map the map
  * @param key the key to look up
  * @param remove flag indicating whether the looked up entry shall be removed
- * @return the value corresponding to the key or \c NULL
+ * @return a pointer to the value corresponding to the key or \c NULL
  */
 static void *cx_hash_map_get_remove(
         CxMap *map,
@@ -172,7 +193,12 @@
     while (elm && elm->key.hash <= hash) {
         if (elm->key.hash == hash && elm->key.len == key.len) {
             if (memcmp(elm->key.data.obj, key.data.obj, key.len) == 0) {
-                void *data = elm->data;
+                void *data = NULL;
+                if (map->store_pointers) {
+                    data = *(void **) elm->data;
+                } else if (!remove) {
+                    data = elm->data;
+                }
                 if (remove) {
                     cx_hash_map_unlink(hash_map, slot, prev, elm);
                 }
@@ -215,9 +241,13 @@
 
 static void *cx_hash_map_iter_current_value(void const *it) {
     struct cx_iterator_s const *iter = it;
+    struct cx_hash_map_s const *map = iter->src_handle;
     struct cx_hash_map_element_s *elm = iter->elem_handle;
-    // TODO: return a pointer to data if this map is storing copies
-    return elm->data;
+    if (map->base.store_pointers) {
+        return *(void **) elm->data;
+    } else {
+        return elm->data;
+    }
 }
 
 static bool cx_hash_map_iter_valid(void const *it) {
@@ -274,8 +304,11 @@
         iter->kv_data.value = NULL;
     } else {
         iter->kv_data.key = &elm->key;
-        // TODO: pointer to data if this map is storing copies
-        iter->kv_data.value = elm->data;
+        if (map->base.store_pointers) {
+            iter->kv_data.value = *(void **) elm->data;
+        } else {
+            iter->kv_data.value = elm->data;
+        }
     }
 }
 
@@ -311,8 +344,11 @@
         }
         iter.elem_handle = elm;
         iter.kv_data.key = &elm->key;
-        // TODO: pointer to data if this map is storing copies
-        iter.kv_data.value = elm->data;
+        if (map->store_pointers) {
+            iter.kv_data.value = *(void **) elm->data;
+        } else {
+            iter.kv_data.value = elm->data;
+        }
     } else {
         iter.elem_handle = NULL;
         iter.kv_data.key = NULL;
@@ -372,6 +408,7 @@
 
 CxMap *cxHashMapCreate(
         CxAllocator *allocator,
+        size_t itemsize,
         size_t buckets
 ) {
     if (buckets == 0) {
@@ -391,9 +428,11 @@
     }
 
     // initialize base members
+    map->base.store_pointers = false;
     map->base.cl = &cx_hash_map_class;
     map->base.allocator = allocator;
     map->base.size = 0;
+    map->base.itemsize = itemsize;
 
     return (CxMap *) map;
 }