diff --git a/src/core/ddsi/src/ddsi_tcp.c b/src/core/ddsi/src/ddsi_tcp.c
index 0ea5cab..7f3b229 100644
--- a/src/core/ddsi/src/ddsi_tcp.c
+++ b/src/core/ddsi/src/ddsi_tcp.c
@@ -73,7 +73,7 @@ typedef struct ddsi_tcp_listener
 }
 * ddsi_tcp_listener_t;
 
-static int ddsi_tcp_cmp_conn (const ddsi_tcp_conn_t c1, const ddsi_tcp_conn_t c2)
+static int ddsi_tcp_cmp_conn (const struct ddsi_tcp_conn *c1, const struct ddsi_tcp_conn *c2)
 {
   const os_sockaddr *a1s = (os_sockaddr *)&c1->m_peer_addr;
   const os_sockaddr *a2s = (os_sockaddr *)&c2->m_peer_addr;
@@ -84,6 +84,11 @@ static int ddsi_tcp_cmp_conn (const ddsi_tcp_conn_t c1, const ddsi_tcp_conn_t c2
   return ddsi_ipaddr_compare (a1s, a2s);
 }
 
+static int ddsi_tcp_cmp_conn_wrap (const void *a, const void *b)
+{
+  return ddsi_tcp_cmp_conn (a, b);
+}
+
 typedef struct ddsi_tcp_node
 {
   ut_avlNode_t m_avlnode;
@@ -95,7 +100,7 @@ static const ut_avlTreedef_t ddsi_tcp_treedef = UT_AVL_TREEDEF_INITIALIZER_INDKE
 (
   offsetof (struct ddsi_tcp_node, m_avlnode),
   offsetof (struct ddsi_tcp_node, m_conn),
-  ddsi_tcp_cmp_conn,
+  ddsi_tcp_cmp_conn_wrap,
   0
 );
 
diff --git a/src/util/include/util/ut_avl.h b/src/util/include/util/ut_avl.h
index 39a68eb..fec0107 100644
--- a/src/util/include/util/ut_avl.h
+++ b/src/util/include/util/ut_avl.h
@@ -190,7 +190,6 @@ typedef struct ut_avlTreedef {
     size_t avlnodeoffset;
     size_t keyoffset;
     union {
-        int (*cmp) ();
         ut_avlCompare_t comparekk;
         ut_avlCompare_r_t comparekk_r;
     } u;
@@ -239,14 +238,14 @@ typedef struct ut_avlCIter {
 } ut_avlCIter_t;
 
 /* avlnodeoffset and keyoffset must both be in [0,2**31-1] */
-#define UT_AVL_TREEDEF_INITIALIZER(avlnodeoffset, keyoffset, comparekk, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), 0, 0 }
-#define UT_AVL_TREEDEF_INITIALIZER_INDKEY(avlnodeoffset, keyoffset, comparekk, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY, 0 }
-#define UT_AVL_TREEDEF_INITIALIZER_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_ALLOWDUPS, 0 }
-#define UT_AVL_TREEDEF_INITIALIZER_INDKEY_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY|UT_AVL_TREEDEF_FLAG_ALLOWDUPS, 0 }
-#define UT_AVL_TREEDEF_INITIALIZER_R(avlnodeoffset, keyoffset, comparekk, cmparg, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_R, (cmparg) }
-#define UT_AVL_TREEDEF_INITIALIZER_INDKEY_R(avlnodeoffset, keyoffset, comparekk, cmparg, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY|UT_AVL_TREEDEF_FLAG_R, (cmparg) }
-#define UT_AVL_TREEDEF_INITIALIZER_R_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk, cmparg, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_R|UT_AVL_TREEDEF_FLAG_ALLOWDUPS, (cmparg) }
-#define UT_AVL_TREEDEF_INITIALIZER_INDKEY_R_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk, cmparg, augment) { (avlnodeoffset), (keyoffset), { (int (*) ()) (comparekk) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY|UT_AVL_TREEDEF_FLAG_R|UT_AVL_TREEDEF_FLAG_ALLOWDUPS, (cmparg) }
+#define UT_AVL_TREEDEF_INITIALIZER(avlnodeoffset, keyoffset, comparekk_, augment) { (avlnodeoffset), (keyoffset), { .comparekk = (comparekk_) }, (augment), 0, 0 }
+#define UT_AVL_TREEDEF_INITIALIZER_INDKEY(avlnodeoffset, keyoffset, comparekk_, augment) { (avlnodeoffset), (keyoffset), { .comparekk = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY, 0 }
+#define UT_AVL_TREEDEF_INITIALIZER_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk_, augment) { (avlnodeoffset), (keyoffset), { .comparekk = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_ALLOWDUPS, 0 }
+#define UT_AVL_TREEDEF_INITIALIZER_INDKEY_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk_, augment) { (avlnodeoffset), (keyoffset), { .comparekk = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY|UT_AVL_TREEDEF_FLAG_ALLOWDUPS, 0 }
+#define UT_AVL_TREEDEF_INITIALIZER_R(avlnodeoffset, keyoffset, comparekk_, cmparg, augment) { (avlnodeoffset), (keyoffset), { .comparekk_r = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_R, (cmparg) }
+#define UT_AVL_TREEDEF_INITIALIZER_INDKEY_R(avlnodeoffset, keyoffset, comparekk_, cmparg, augment) { (avlnodeoffset), (keyoffset), { .comparekk_r = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY|UT_AVL_TREEDEF_FLAG_R, (cmparg) }
+#define UT_AVL_TREEDEF_INITIALIZER_R_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk_, cmparg, augment) { (avlnodeoffset), (keyoffset), { .comparekk_r = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_R|UT_AVL_TREEDEF_FLAG_ALLOWDUPS, (cmparg) }
+#define UT_AVL_TREEDEF_INITIALIZER_INDKEY_R_ALLOWDUPS(avlnodeoffset, keyoffset, comparekk_, cmparg, augment) { (avlnodeoffset), (keyoffset), { .comparekk_r = (comparekk_) }, (augment), UT_AVL_TREEDEF_FLAG_INDKEY|UT_AVL_TREEDEF_FLAG_R|UT_AVL_TREEDEF_FLAG_ALLOWDUPS, (cmparg) }
 
 /* Not maintaining # nodes */
 
diff --git a/src/util/src/ut_avl.c b/src/util/src/ut_avl.c
index 1913916..01598fc 100644
--- a/src/util/src/ut_avl.c
+++ b/src/util/src/ut_avl.c
@@ -91,26 +91,27 @@ static const char *conode_from_node (const ut_avlTreedef_t *td, const ut_avlNode
     }
 }
 
-static void treedef_init_common (ut_avlTreedef_t *td, size_t avlnodeoffset, size_t keyoffset, int (*cmp) (), ut_avlAugment_t augment, uint32_t flags)
+static void treedef_init_common (ut_avlTreedef_t *td, size_t avlnodeoffset, size_t keyoffset, ut_avlAugment_t augment, uint32_t flags)
 {
     assert (avlnodeoffset <= 0x7fffffff);
     assert (keyoffset <= 0x7fffffff);
     td->avlnodeoffset = avlnodeoffset;
     td->keyoffset = keyoffset;
-    td->u.cmp = cmp;
     td->augment = augment;
     td->flags = flags;
 }
 
 void ut_avlTreedefInit (_Out_ ut_avlTreedef_t *td, size_t avlnodeoffset, size_t keyoffset, _In_ ut_avlCompare_t comparekk, _In_opt_ ut_avlAugment_t augment, uint32_t flags)
 {
-    treedef_init_common (td, avlnodeoffset, keyoffset, (int (*) ()) comparekk, augment, flags);
+    treedef_init_common (td, avlnodeoffset, keyoffset, augment, flags);
+    td->u.comparekk = comparekk;
 }
 
 void ut_avlTreedefInit_r (_Out_ ut_avlTreedef_t *td, size_t avlnodeoffset, size_t keyoffset, _In_ ut_avlCompare_r_t comparekk_r, _Inout_opt_ void *cmp_arg, ut_avlAugment_t augment, uint32_t flags)
 {
+    treedef_init_common (td, avlnodeoffset, keyoffset, augment, flags | UT_AVL_TREEDEF_FLAG_R);
     td->cmp_arg = cmp_arg;
-    treedef_init_common (td, avlnodeoffset, keyoffset, (int (*) ()) comparekk_r, augment, flags | UT_AVL_TREEDEF_FLAG_R);
+    td->u.comparekk_r = comparekk_r;
 }
 
 void ut_avlInit (_In_ const ut_avlTreedef_t *td, _Out_ ut_avlTree_t *tree)
@@ -256,11 +257,11 @@ static ut_avlNode_t *rotate (const ut_avlTreedef_t *td, ut_avlNode_t **pnode, ut
        rotation, _ND_D means the grandchild that is the right child of
        the left child. */
     ut_avlNode_t * const node_ND = node->cs[1-dir];
+    assert (node_ND != NULL);
     ut_avlNode_t * const node_ND_ND = node_ND->cs[1-dir];
     ut_avlNode_t * const node_ND_D = node_ND->cs[dir];
     int height_ND_ND, height_ND_D;
     assert (dir == !!dir);
-    assert (node_ND != NULL);
     height_ND_ND = node_ND_ND ? node_ND_ND->height : 0;
     height_ND_D = node_ND_D ? node_ND_D->height : 0;
     if (height_ND_ND < height_ND_D) {
@@ -948,13 +949,15 @@ _Ret_notnull_ void *ut_avlRootNonEmpty (_In_ const ut_avlTreedef_t *td, _In_ con
 
 void ut_avlCTreedefInit (_Out_ ut_avlCTreedef_t *td, size_t avlnodeoffset, size_t keyoffset, _In_ ut_avlCompare_t comparekk, _In_opt_ ut_avlAugment_t augment, uint32_t flags)
 {
-    treedef_init_common (&td->t, avlnodeoffset, keyoffset, (int (*) ()) comparekk, augment, flags);
+    treedef_init_common (&td->t, avlnodeoffset, keyoffset, augment, flags);
+    td->t.u.comparekk = comparekk;
 }
 
 void ut_avlCTreedefInit_r (_Out_ ut_avlCTreedef_t *td, size_t avlnodeoffset, size_t keyoffset, _In_ ut_avlCompare_r_t comparekk_r, _Inout_opt_ void *cmp_arg, _In_opt_ ut_avlAugment_t augment, uint32_t flags)
 {
+    treedef_init_common (&td->t, avlnodeoffset, keyoffset, augment, flags | UT_AVL_TREEDEF_FLAG_R);
     td->t.cmp_arg = cmp_arg;
-    treedef_init_common (&td->t, avlnodeoffset, keyoffset, (int (*) ()) comparekk_r, augment, flags | UT_AVL_TREEDEF_FLAG_R);
+    td->t.u.comparekk_r = comparekk_r;
 }
 
 void ut_avlCInit (_In_ const ut_avlCTreedef_t *td, _Out_ ut_avlCTree_t *tree)