diff --git a/src/core/ddsc/src/dds_reader.c b/src/core/ddsc/src/dds_reader.c
index b3f241b..b039495 100644
--- a/src/core/ddsc/src/dds_reader.c
+++ b/src/core/ddsc/src/dds_reader.c
@@ -472,11 +472,11 @@ dds_create_reader(
     ddsrt_mutex_unlock(&sub->m_entity.m_mutex);
 
     thread_state_awake (lookup_thread_state ());
-    rd->m_rd = new_reader(&rd->m_entity.m_guid, NULL, &sub->m_entity.m_participant->m_guid, tp->m_stopic,
-                          rqos, rhc, dds_reader_status_cb, rd);
+    ret = new_reader(&rd->m_rd, &rd->m_entity.m_guid, NULL, &sub->m_entity.m_participant->m_guid, tp->m_stopic,
+                     rqos, rhc, dds_reader_status_cb, rd);
     ddsrt_mutex_lock(&sub->m_entity.m_mutex);
     ddsrt_mutex_lock(&tp->m_entity.m_mutex);
-    assert (rd->m_rd);
+    assert (ret == DDS_RETCODE_OK);
     thread_state_asleep (lookup_thread_state ());
 
     /* For persistent data register reader with durability */
diff --git a/src/core/ddsc/src/dds_writer.c b/src/core/ddsc/src/dds_writer.c
index 5bd81d6..cd83d3e 100644
--- a/src/core/ddsc/src/dds_writer.c
+++ b/src/core/ddsc/src/dds_writer.c
@@ -456,10 +456,10 @@ dds_create_writer(
     ddsrt_mutex_unlock (&pub->m_entity.m_mutex);
 
     thread_state_awake (lookup_thread_state ());
-    wr->m_wr = new_writer(&wr->m_entity.m_guid, NULL, &pub->m_entity.m_participant->m_guid, tp->m_stopic, wqos, wr->m_whc, dds_writer_status_cb, wr);
+    ret = new_writer(&wr->m_wr, &wr->m_entity.m_guid, NULL, &pub->m_entity.m_participant->m_guid, tp->m_stopic, wqos, wr->m_whc, dds_writer_status_cb, wr);
     ddsrt_mutex_lock (&pub->m_entity.m_mutex);
     ddsrt_mutex_lock (&tp->m_entity.m_mutex);
-    assert(wr->m_wr);
+    assert(ret == DDS_RETCODE_OK);
     thread_state_asleep (lookup_thread_state ());
     dds_topic_unlock(tp);
     dds_publisher_unlock(pub);
diff --git a/src/core/ddsi/include/dds/ddsi/q_entity.h b/src/core/ddsi/include/dds/ddsi/q_entity.h
index 6f79aac..9138e02 100644
--- a/src/core/ddsi/include/dds/ddsi/q_entity.h
+++ b/src/core/ddsi/include/dds/ddsi/q_entity.h
@@ -479,9 +479,9 @@ struct writer *get_builtin_writer (const struct participant *pp, unsigned entity
    GUID "ppguid". May return NULL if participant unknown or
    writer/reader already known. */
 
-struct writer *new_writer (struct nn_guid *wrguid, const struct nn_guid *group_guid, const struct nn_guid *ppguid, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc * whc, status_cb_t status_cb, void *status_cb_arg);
+dds_retcode_t new_writer (struct writer **wr_out, struct nn_guid *wrguid, const struct nn_guid *group_guid, const struct nn_guid *ppguid, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc * whc, status_cb_t status_cb, void *status_cb_arg);
 
-struct reader *new_reader (struct nn_guid *rdguid, const struct nn_guid *group_guid, const struct nn_guid *ppguid, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct rhc * rhc, status_cb_t status_cb, void *status_cb_arg);
+dds_retcode_t new_reader (struct reader **rd_out, struct nn_guid *rdguid, const struct nn_guid *group_guid, const struct nn_guid *ppguid, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct rhc * rhc, status_cb_t status_cb, void *status_cb_arg);
 
 struct whc_node;
 struct whc_state;
diff --git a/src/core/ddsi/src/q_entity.c b/src/core/ddsi/src/q_entity.c
index 3dffa18..565c72b 100644
--- a/src/core/ddsi/src/q_entity.c
+++ b/src/core/ddsi/src/q_entity.c
@@ -88,8 +88,8 @@ static const unsigned prismtech_builtin_writers_besmask =
   NN_DISC_BUILTIN_ENDPOINT_CM_PUBLISHER_WRITER |
   NN_DISC_BUILTIN_ENDPOINT_CM_SUBSCRIBER_WRITER;
 
-static struct writer * new_writer_guid (const struct nn_guid *guid, const struct nn_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc *whc, status_cb_t status_cb, void *status_cbarg);
-static struct reader * new_reader_guid (const struct nn_guid *guid, const struct nn_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct rhc *rhc, status_cb_t status_cb, void *status_cbarg);
+static dds_retcode_t new_writer_guid (struct writer **wr_out, const struct nn_guid *guid, const struct nn_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc *whc, status_cb_t status_cb, void *status_cbarg);
+static dds_retcode_t new_reader_guid (struct reader **rd_out, const struct nn_guid *guid, const struct nn_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct rhc *rhc, status_cb_t status_cb, void *status_cbarg);
 static struct participant *ref_participant (struct participant *pp, const struct nn_guid *guid_of_refing_entity);
 static void unref_participant (struct participant *pp, const struct nn_guid *guid_of_refing_entity);
 static void delete_proxy_group_locked (struct proxy_group *pgroup, nn_wctime_t timestamp, int isimplicit);
@@ -488,7 +488,7 @@ int new_participant_guid (const nn_guid_t *ppguid, unsigned flags, const nn_plis
   if (!(flags & RTPS_PF_NO_BUILTIN_WRITERS))
   {
     subguid.entityid = to_entityid (NN_ENTITYID_SPDP_BUILTIN_PARTICIPANT_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.spdp_endpoint_xqos, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.spdp_endpoint_xqos, whc_new(1, 1, 1), LAST_WR_PARAMS);
     /* But we need the as_disc address set for SPDP, because we need to
        send it to everyone regardless of the existence of readers. */
     {
@@ -511,23 +511,23 @@ int new_participant_guid (const nn_guid_t *ppguid, unsigned flags, const nn_plis
   if (!(flags & RTPS_PF_NO_BUILTIN_WRITERS))
   {
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_SUBSCRIPTIONS_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->bes |= NN_DISC_BUILTIN_ENDPOINT_SUBSCRIPTION_ANNOUNCER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_PUBLICATIONS_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->bes |= NN_DISC_BUILTIN_ENDPOINT_PUBLICATION_ANNOUNCER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_CM_PARTICIPANT_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->prismtech_bes |= NN_DISC_BUILTIN_ENDPOINT_CM_PARTICIPANT_WRITER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_CM_PUBLISHER_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->prismtech_bes |= NN_DISC_BUILTIN_ENDPOINT_CM_PUBLISHER_WRITER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_CM_SUBSCRIBER_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->prismtech_bes |= NN_DISC_BUILTIN_ENDPOINT_CM_SUBSCRIBER_WRITER;
   }
 
@@ -535,7 +535,7 @@ int new_participant_guid (const nn_guid_t *ppguid, unsigned flags, const nn_plis
   {
     /* TODO: make this one configurable, we don't want all participants to publish all topics (or even just those that they use themselves) */
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_TOPIC_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->bes |= NN_DISC_BUILTIN_ENDPOINT_TOPIC_ANNOUNCER;
   }
 
@@ -543,7 +543,7 @@ int new_participant_guid (const nn_guid_t *ppguid, unsigned flags, const nn_plis
   if (!(flags & RTPS_PF_NO_BUILTIN_WRITERS))
   {
     subguid.entityid = to_entityid (NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_MESSAGE_WRITER);
-    new_writer_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
+    new_writer_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_wr, whc_new(1, 1, 1), LAST_WR_PARAMS);
     pp->bes |= NN_BUILTIN_ENDPOINT_PARTICIPANT_MESSAGE_DATA_WRITER;
   }
 
@@ -551,31 +551,31 @@ int new_participant_guid (const nn_guid_t *ppguid, unsigned flags, const nn_plis
   if (!(flags & RTPS_PF_NO_BUILTIN_READERS))
   {
     subguid.entityid = to_entityid (NN_ENTITYID_SPDP_BUILTIN_PARTICIPANT_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.spdp_endpoint_xqos, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.spdp_endpoint_xqos, NULL, NULL, NULL);
     pp->bes |= NN_DISC_BUILTIN_ENDPOINT_PARTICIPANT_DETECTOR;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_SUBSCRIPTIONS_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
     pp->bes |= NN_DISC_BUILTIN_ENDPOINT_SUBSCRIPTION_DETECTOR;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_PUBLICATIONS_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
     pp->bes |= NN_DISC_BUILTIN_ENDPOINT_PUBLICATION_DETECTOR;
 
     subguid.entityid = to_entityid (NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_MESSAGE_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
     pp->bes |= NN_BUILTIN_ENDPOINT_PARTICIPANT_MESSAGE_DATA_READER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_CM_PARTICIPANT_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
     pp->prismtech_bes |= NN_DISC_BUILTIN_ENDPOINT_CM_PARTICIPANT_READER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_CM_PUBLISHER_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
     pp->prismtech_bes |= NN_DISC_BUILTIN_ENDPOINT_CM_PUBLISHER_READER;
 
     subguid.entityid = to_entityid (NN_ENTITYID_SEDP_BUILTIN_CM_SUBSCRIBER_READER);
-    new_reader_guid (&subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
+    new_reader_guid (NULL, &subguid, &group_guid, pp, NULL, &gv.builtin_endpoint_xqos_rd, NULL, NULL, NULL);
     pp->prismtech_bes |= NN_DISC_BUILTIN_ENDPOINT_CM_SUBSCRIBER_READER;
 
   }
@@ -2779,7 +2779,7 @@ static void new_writer_guid_common_init (struct writer *wr, const struct ddsi_se
   local_reader_ary_init (&wr->rdary);
 }
 
-static struct writer *new_writer_guid (const struct nn_guid *guid, const struct nn_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc *whc, status_cb_t status_cb, void *status_entity)
+static dds_retcode_t new_writer_guid (struct writer **wr_out, const struct nn_guid *guid, const struct nn_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc *whc, status_cb_t status_cb, void *status_entity)
 {
   struct writer *wr;
   nn_mtime_t tnow = now_mt ();
@@ -2790,6 +2790,8 @@ static struct writer *new_writer_guid (const struct nn_guid *guid, const struct
 
   new_reader_writer_common (guid, topic, xqos);
   wr = ddsrt_malloc (sizeof (*wr));
+  if (wr_out)
+    *wr_out = wr;
 
   /* want a pointer to the participant so that a parallel call to
    delete_participant won't interfere with our ability to address
@@ -2822,27 +2824,25 @@ static struct writer *new_writer_guid (const struct nn_guid *guid, const struct
     resched_xevent_if_earlier (pp->pmd_update_xevent, tsched);
   }
 
-  return wr;
+  return DDS_RETCODE_OK;
 }
 
-struct writer *new_writer (struct nn_guid *wrguid, const struct nn_guid *group_guid, const struct nn_guid *ppguid, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc * whc, status_cb_t status_cb, void *status_cb_arg)
+dds_retcode_t new_writer (struct writer **wr_out, struct nn_guid *wrguid, const struct nn_guid *group_guid, const struct nn_guid *ppguid, const struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc * whc, status_cb_t status_cb, void *status_cb_arg)
 {
   struct participant *pp;
-  struct writer * wr;
 
   if ((pp = ephash_lookup_participant_guid (ppguid)) == NULL)
   {
     DDS_LOG(DDS_LC_DISCOVERY, "new_writer - participant %x:%x:%x:%x not found\n", PGUID (*ppguid));
-    return NULL;
+    return DDS_RETCODE_NOT_FOUND;
   }
   /* participant can't be freed while we're mucking around cos we are
      awake and do not touch the thread's vtime (ephash_lookup already
      verifies we're awake) */
   wrguid->prefix = pp->e.guid.prefix;
   if (pp_allocate_entityid (&wrguid->entityid, NN_ENTITYID_KIND_WRITER_WITH_KEY, pp) < 0)
-    return NULL;
-  wr = new_writer_guid (wrguid, group_guid, pp, topic, xqos, whc, status_cb, status_cb_arg);
-  return wr;
+    return DDS_RETCODE_OUT_OF_RESOURCES;
+  return new_writer_guid (wr_out, wrguid, group_guid, pp, topic, xqos, whc, status_cb, status_cb_arg);
 }
 
 struct local_orphan_writer *new_local_orphan_writer (nn_entityid_t entityid, struct ddsi_sertopic *topic, const struct nn_xqos *xqos, struct whc *whc)
@@ -3170,8 +3170,9 @@ static void leave_mcast_helper (const nn_locator_t *n, void * varg)
 }
 #endif /* DDSI_INCLUDE_NETWORK_PARTITIONS */
 
-static struct reader * new_reader_guid
+static dds_retcode_t new_reader_guid
 (
+  struct reader **rd_out,
   const struct nn_guid *guid,
   const struct nn_guid *group_guid,
   struct participant *pp,
@@ -3193,6 +3194,8 @@ static struct reader * new_reader_guid
 
   new_reader_writer_common (guid, topic, xqos);
   rd = ddsrt_malloc (sizeof (*rd));
+  if (rd_out)
+    *rd_out = rd;
 
   endpoint_common_init (&rd->e, &rd->c, EK_READER, guid, group_guid, pp);
 
@@ -3300,11 +3303,12 @@ static struct reader * new_reader_guid
   match_reader_with_local_writers (rd, tnow);
   ddsi_plugin.builtintopic_write (&rd->e, now(), true);
   sedp_write_reader (rd);
-  return rd;
+  return DDS_RETCODE_OK;
 }
 
-struct reader * new_reader
+dds_retcode_t new_reader
 (
+  struct reader **rd_out,
   struct nn_guid *rdguid,
   const struct nn_guid *group_guid,
   const struct nn_guid *ppguid,
@@ -3316,18 +3320,16 @@ struct reader * new_reader
 )
 {
   struct participant * pp;
-  struct reader * rd;
 
   if ((pp = ephash_lookup_participant_guid (ppguid)) == NULL)
   {
     DDS_LOG(DDS_LC_DISCOVERY, "new_reader - participant %x:%x:%x:%x not found\n", PGUID (*ppguid));
-    return NULL;
+    return DDS_RETCODE_NOT_FOUND;
   }
   rdguid->prefix = pp->e.guid.prefix;
   if (pp_allocate_entityid (&rdguid->entityid, NN_ENTITYID_KIND_READER_WITH_KEY, pp) < 0)
-    return NULL;
-  rd = new_reader_guid (rdguid, group_guid, pp, topic, xqos, rhc, status_cb, status_cbarg);
-  return rd;
+    return DDS_RETCODE_OUT_OF_RESOURCES;
+  return new_reader_guid (rd_out, rdguid, group_guid, pp, topic, xqos, rhc, status_cb, status_cbarg);
 }
 
 static void gc_delete_reader (struct gcreq *gcreq)