diff --git a/src/core/ddsc/src/dds_read.c b/src/core/ddsc/src/dds_read.c
index 394b7e4..701f50d 100644
--- a/src/core/ddsc/src/dds_read.c
+++ b/src/core/ddsc/src/dds_read.c
@@ -94,7 +94,6 @@ static dds_return_t dds_read_impl (bool take, dds_entity_t reader_or_condition,
           rd->m_loan = buf[0];
           rd->m_loan_size = maxs;
         }
-        nodata_cleanups = NC_RESET_BUF;
       }
       else
       {
@@ -103,7 +102,7 @@ static dds_return_t dds_read_impl (bool take, dds_entity_t reader_or_condition,
         rd->m_loan_size = maxs;
       }
       rd->m_loan_out = true;
-      nodata_cleanups |= NC_CLEAR_LOAN_OUT;
+      nodata_cleanups = NC_RESET_BUF | NC_CLEAR_LOAN_OUT;
     }
     ddsrt_mutex_unlock (&rd->m_entity.m_mutex);
   }
@@ -457,12 +456,11 @@ dds_return_t dds_take_next_wl (dds_entity_t reader, void **buf, dds_sample_info_
 
 dds_return_t dds_return_loan (dds_entity_t reader_or_condition, void **buf, int32_t bufsz)
 {
-  const struct ddsi_sertopic *st;
   dds_reader *rd;
   dds_entity *entity;
-  dds_return_t ret = DDS_RETCODE_OK;
+  dds_return_t ret;
 
-  if (buf == NULL || (*buf == NULL && bufsz > 0))
+  if (buf == NULL || (buf[0] == NULL && bufsz > 0) || (buf[0] != NULL && bufsz <= 0))
     return DDS_RETCODE_BAD_PARAMETER;
 
   if ((ret = dds_entity_pin (reader_or_condition, &entity)) < 0) {
@@ -476,16 +474,46 @@ dds_return_t dds_return_loan (dds_entity_t reader_or_condition, void **buf, int3
     rd = (dds_reader *) entity->m_parent;
   }
 
-  st = rd->m_topic->m_stopic;
-  for (int32_t i = 0; i < bufsz; i++)
-    ddsi_sertopic_free_sample (st, buf[i], DDS_FREE_CONTENTS);
-
-  /* If possible return loan buffer to reader */
-  ddsrt_mutex_lock (&rd->m_entity.m_mutex);
-  if (rd->m_loan != 0 && (buf[0] == rd->m_loan))
+  if (bufsz <= 0)
   {
-    rd->m_loan_out = false;
+    /* No data whatsoever, or an invocation following a failed read/take call.  Read/take
+       already take care of restoring the state prior to their invocation if they return
+       no data.  Return late so invalid handles can be detected. */
+    dds_entity_unpin (entity);
+    return DDS_RETCODE_OK;
+  }
+  assert (buf[0] != NULL);
+
+  const struct ddsi_sertopic *st = rd->m_topic->m_stopic;
+
+  /* The potentially time consuming part of what happens here (freeing samples)
+     can safely be done without holding the reader lock, but that particular
+     lock is not used during insertion of data & triggering waitsets (that's
+     the observer_lock), so holding it for a bit longer in return for simpler
+     code is a fair trade-off. */
+  ddsrt_mutex_lock (&rd->m_entity.m_mutex);
+  if (buf[0] != rd->m_loan)
+  {
+    /* Not so much a loan as a buffer allocated by the middleware on behalf of the
+       application.  So it really is no more than a sophisticated variant of "free". */
+    ddsi_sertopic_free_samples (st, buf, (size_t) bufsz, DDS_FREE_ALL);
+    buf[0] = NULL;
+  }
+  else if (!rd->m_loan_out)
+  {
+    /* Trying to return a loan that has been returned already */
+    ddsrt_mutex_unlock (&rd->m_entity.m_mutex);
+    dds_entity_unpin (entity);
+    return DDS_RETCODE_PRECONDITION_NOT_MET;
+  }
+  else
+  {
+    /* Free only the memory referenced from the samples, not the samples themselves.
+       Zero them to guarantee the absence of dangling pointers that might cause
+       trouble on a following operation.  FIXME: there's got to be a better way */
+    ddsi_sertopic_free_samples (st, buf, (size_t) bufsz, DDS_FREE_CONTENTS);
     ddsi_sertopic_zero_samples (st, rd->m_loan, rd->m_loan_size);
+    rd->m_loan_out = false;
     buf[0] = NULL;
   }
   ddsrt_mutex_unlock (&rd->m_entity.m_mutex);
diff --git a/src/core/ddsc/tests/CMakeLists.txt b/src/core/ddsc/tests/CMakeLists.txt
index 4a234eb..2dac5e3 100644
--- a/src/core/ddsc/tests/CMakeLists.txt
+++ b/src/core/ddsc/tests/CMakeLists.txt
@@ -30,6 +30,7 @@ set(ddsc_test_sources
     "instance_get_key.c"
     "listener.c"
     "liveliness.c"
+    "loan.c"
     "multi_sertopic.c"
     "participant.c"
     "publisher.c"
@@ -41,7 +42,6 @@ set(ddsc_test_sources
     "reader_iterator.c"
     "read_instance.c"
     "register.c"
-    "return_loan.c"
     "subscriber.c"
     "take_instance.c"
     "time.c"
@@ -55,7 +55,9 @@ set(ddsc_test_sources
     "whc.c"
     "write.c"
     "write_various_types.c"
-    "writer.c")
+    "writer.c"
+    "test_common.c"
+    "test_common.h")
 
 if(ENABLE_LIFESPAN)
   list(APPEND ddsc_test_sources "lifespan.c")
diff --git a/src/core/ddsc/tests/basic.c b/src/core/ddsc/tests/basic.c
index b2bb597..d08b5b6 100644
--- a/src/core/ddsc/tests/basic.c
+++ b/src/core/ddsc/tests/basic.c
@@ -10,7 +10,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds/dds.h"
-#include "CUnit/Test.h"
+#include "test_common.h"
 
 CU_Test(ddsc_basic, test)
 {
diff --git a/src/core/ddsc/tests/builtin_topics.c b/src/core/ddsc/tests/builtin_topics.c
index 747b1d2..3c511fd 100644
--- a/src/core/ddsc/tests/builtin_topics.c
+++ b/src/core/ddsc/tests/builtin_topics.c
@@ -10,10 +10,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds/dds.h"
-#include "RoundTrip.h"
-#include "Space.h"
-#include "test-common.h"
-#include "CUnit/Test.h"
+#include "test_common.h"
 
 static dds_entity_t g_participant = 0;
 static dds_entity_t g_subscriber  = 0;
@@ -336,7 +333,7 @@ CU_Test(ddsc_builtin_topics, read_nothing)
   CU_ASSERT_FATAL (ret == 0);
   ret = dds_return_loan (rd, &raw2, n2);
   CU_ASSERT_FATAL (ret == 0);
-  
+
   ret = dds_delete (pp);
   CU_ASSERT_FATAL (ret == 0);
 }
diff --git a/src/core/ddsc/tests/config.c b/src/core/ddsc/tests/config.c
index 159a4ac..bb8f234 100644
--- a/src/core/ddsc/tests/config.c
+++ b/src/core/ddsc/tests/config.c
@@ -12,7 +12,6 @@
 #include <stdlib.h>
 
 #include "dds/dds.h"
-#include "CUnit/Test.h"
 #include "config_env.h"
 
 #include "dds/version.h"
@@ -22,6 +21,8 @@
 #include "dds/ddsi/q_misc.h"
 #include "dds/ddsi/ddsi_xqos.h"
 
+#include "test_common.h"
+
 #define FORCE_ENV
 
 #define URI_VARIABLE DDS_PROJECT_NAME_NOSPACE_CAPS"_URI"
diff --git a/src/core/ddsc/tests/deadline.c b/src/core/ddsc/tests/deadline.c
index 818847a..e10bd74 100644
--- a/src/core/ddsc/tests/deadline.c
+++ b/src/core/ddsc/tests/deadline.c
@@ -13,9 +13,6 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 #include "dds/ddsrt/environ.h"
@@ -24,6 +21,8 @@
 #include "dds/ddsi/q_whc.h"
 #include "dds__entity.h"
 
+#include "test_common.h"
+
 #define MAX_RUNS 4
 #define WRITER_DEADLINE DDS_MSECS(50)
 
@@ -42,15 +41,6 @@ static dds_entity_t g_remote_participant = 0;
 static dds_entity_t g_remote_subscriber  = 0;
 static dds_entity_t g_remote_topic       = 0;
 
-
-static char * create_topic_name(const char *prefix, char *name, size_t size)
-{
-  ddsrt_pid_t pid = ddsrt_getpid();
-  ddsrt_tid_t tid = ddsrt_gettid();
-  (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-  return name;
-}
-
 static void sync_reader_writer(dds_entity_t participant, dds_entity_t reader, dds_entity_t writer)
 {
   dds_attach_t triggered;
@@ -126,7 +116,7 @@ static void deadline_init(void)
   g_publisher = dds_create_publisher(g_participant, NULL, NULL);
   CU_ASSERT_FATAL(g_publisher > 0);
 
-  create_topic_name("ddsc_qos_deadline_test", name, sizeof name);
+  create_unique_topic_name("ddsc_qos_deadline_test", name, sizeof name);
   g_topic = dds_create_topic(g_participant, &Space_Type1_desc, name, NULL, NULL);
   CU_ASSERT_FATAL(g_topic > 0);
   g_remote_topic = dds_create_topic(g_remote_participant, &Space_Type1_desc, name, NULL, NULL);
diff --git a/src/core/ddsc/tests/dispose.c b/src/core/ddsc/tests/dispose.c
index ef6435f..b0a0dc4 100644
--- a/src/core/ddsc/tests/dispose.c
+++ b/src/core/ddsc/tests/dispose.c
@@ -12,13 +12,12 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -41,16 +40,6 @@ static void*             g_samples[MAX_SAMPLES];
 static Space_Type1       g_data[MAX_SAMPLES];
 static dds_sample_info_t g_info[MAX_SAMPLES];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 disposing_init(void)
 {
@@ -69,7 +58,7 @@ disposing_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_disposing_test", name, sizeof name), qos, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_disposing_test", name, sizeof name), qos, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a reader that keeps one sample on three instances. */
diff --git a/src/core/ddsc/tests/entity_hierarchy.c b/src/core/ddsc/tests/entity_hierarchy.c
index 44d5917..851cadb 100644
--- a/src/core/ddsc/tests/entity_hierarchy.c
+++ b/src/core/ddsc/tests/entity_hierarchy.c
@@ -12,14 +12,12 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Test.h"
-#include "CUnit/Theory.h"
-#include "RoundTrip.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -44,16 +42,6 @@ accept_all(const void * sample)
     return true;
 }
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 hierarchy_init(void)
 {
@@ -63,7 +51,7 @@ hierarchy_init(void)
     g_participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(g_participant > 0 );
 
-    g_topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_hierarchy_test", name, sizeof name), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_hierarchy_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     g_publisher = dds_create_publisher(g_participant, NULL, NULL);
@@ -179,7 +167,7 @@ CU_Test(ddsc_entity_delete, recursive_with_deleted_topic)
     /* First, create a topic and a writer with that topic. */
     g_participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(g_participant > 0);
-    g_topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_hierarchy_test", name, 100), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_hierarchy_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
     g_writer = dds_create_writer(g_participant, g_topic, NULL, NULL);
     CU_ASSERT_FATAL(g_writer> 0);
@@ -747,7 +735,7 @@ CU_Test(ddsc_entity_implicit_publisher, deleted)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_publisher_test", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_publisher_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     writer = dds_create_writer(participant, topic, NULL, NULL);
@@ -799,7 +787,7 @@ CU_Test(ddsc_entity_implicit_subscriber, deleted)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_subscriber_test", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_subscriber_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     reader = dds_create_reader(participant, topic, NULL, NULL);
@@ -854,7 +842,7 @@ CU_Test(ddsc_entity_get_children, implicit_publisher)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_publisher_test", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_publisher_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     writer = dds_create_writer(participant, topic, NULL, NULL);
@@ -898,7 +886,7 @@ CU_Test(ddsc_entity_get_children, implicit_subscriber)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_subscriber_test", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_subscriber_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     reader = dds_create_reader(participant, topic, NULL, NULL);
@@ -942,7 +930,7 @@ CU_Test(ddsc_entity_get_parent, implicit_publisher)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_publisher_promotion_test", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_publisher_promotion_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     writer = dds_create_writer(participant, topic, NULL, NULL);
@@ -973,7 +961,7 @@ CU_Test(ddsc_entity_get_parent, implicit_subscriber)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_subscriber_promotion_test", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_subscriber_promotion_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     reader = dds_create_reader(participant, topic, NULL, NULL);
@@ -1005,7 +993,7 @@ CU_Test(ddsc_entity_implicit, delete_publisher)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_delete_publisher", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_delete_publisher", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     writer = dds_create_writer(participant, topic, NULL, NULL);
@@ -1037,7 +1025,7 @@ CU_Test(ddsc_entity_implicit, delete_subscriber)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(participant > 0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_entity_implicit_delete_subscriber", name, 100), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_entity_implicit_delete_subscriber", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(topic > 0);
 
     reader = dds_create_reader(participant, topic, NULL, NULL);
diff --git a/src/core/ddsc/tests/entity_status.c b/src/core/ddsc/tests/entity_status.c
index 297f2cd..be14103 100644
--- a/src/core/ddsc/tests/entity_status.c
+++ b/src/core/ddsc/tests/entity_status.c
@@ -11,13 +11,13 @@
  */
 #include <limits.h>
 #include <stdlib.h>
-#include "CUnit/Theory.h"
-#include "dds/dds.h"
-#include "RoundTrip.h"
 
+#include "dds/dds.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /****************************************************************************
  * Test globals.
  ****************************************************************************/
@@ -56,15 +56,6 @@ static dds_instance_handle_t writer_i_hdl = 0;
 /****************************************************************************
  * Test initializations and teardowns.
  ****************************************************************************/
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
 
 static void
 init_entity_status(void)
@@ -74,7 +65,7 @@ init_entity_status(void)
     participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT(participant > 0);
 
-    top = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_status_test", topicName, 100), NULL, NULL);
+    top = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_status_test", topicName, 100), NULL, NULL);
     CU_ASSERT(top > 0);
 
     qos = dds_create_qos();
diff --git a/src/core/ddsc/tests/lifespan.c b/src/core/ddsc/tests/lifespan.c
index fea4079..ff296c4 100644
--- a/src/core/ddsc/tests/lifespan.c
+++ b/src/core/ddsc/tests/lifespan.c
@@ -13,9 +13,6 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 #include "dds/ddsi/ddsi_entity_index.h"
@@ -23,6 +20,8 @@
 #include "dds/ddsi/q_whc.h"
 #include "dds__entity.h"
 
+#include "test_common.h"
+
 static dds_entity_t g_participant = 0;
 static dds_entity_t g_subscriber  = 0;
 static dds_entity_t g_publisher   = 0;
@@ -33,16 +32,6 @@ static dds_entity_t g_waitset     = 0;
 static dds_entity_t g_rcond       = 0;
 static dds_entity_t g_qcond       = 0;
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void lifespan_init(void)
 {
   dds_attach_t triggered;
@@ -65,7 +54,7 @@ static void lifespan_init(void)
   g_waitset = dds_create_waitset(g_participant);
   CU_ASSERT_FATAL(g_waitset > 0);
 
-  g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_qos_lifespan_test", name, sizeof name), NULL, NULL);
+  g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_qos_lifespan_test", name, sizeof name), NULL, NULL);
   CU_ASSERT_FATAL(g_topic > 0);
 
   dds_qset_history(qos, DDS_HISTORY_KEEP_ALL, DDS_LENGTH_UNLIMITED);
diff --git a/src/core/ddsc/tests/listener.c b/src/core/ddsc/tests/listener.c
index 49a2915..1ad9f71 100644
--- a/src/core/ddsc/tests/listener.c
+++ b/src/core/ddsc/tests/listener.c
@@ -10,8 +10,6 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds/dds.h"
-#include "RoundTrip.h"
-#include "CUnit/Test.h"
 
 #include "dds/ddsrt/cdtors.h"
 #include "dds/ddsrt/misc.h"
@@ -19,6 +17,8 @@
 #include "dds/ddsrt/sync.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /****************************************************************************
  * TODO: Add DDS_INCONSISTENT_TOPIC_STATUS test
  * TODO: Add DDS_OFFERED/REQUESTED_DEADLINE_MISSED_STATUS test
@@ -311,15 +311,6 @@ waitfor_cb(uint32_t expected)
 /****************************************************************************
  * Test initializations and teardowns.
  ****************************************************************************/
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
 
 static void
 init_triggering_base(void)
@@ -340,7 +331,7 @@ init_triggering_base(void)
     g_publisher = dds_create_publisher(g_participant, NULL, NULL);
     CU_ASSERT_FATAL(g_publisher > 0);
 
-    g_topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_listener_test", name, 100), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_listener_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     g_listener = dds_create_listener(NULL);
diff --git a/src/core/ddsc/tests/liveliness.c b/src/core/ddsc/tests/liveliness.c
index 04cec98..cf3adab 100644
--- a/src/core/ddsc/tests/liveliness.c
+++ b/src/core/ddsc/tests/liveliness.c
@@ -13,8 +13,6 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
 #include "config_env.h"
 
 #include "dds/version.h"
@@ -29,12 +27,13 @@
 #include "dds/ddsrt/atomics.h"
 #include "dds/ddsrt/time.h"
 
+#include "test_common.h"
+
 #define DDS_DOMAINID_PUB 0
 #define DDS_DOMAINID_SUB 1
 #define DDS_CONFIG_NO_PORT_GAIN "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Discovery><ExternalDomainId>0</ExternalDomainId></Discovery>"
 #define DDS_CONFIG_NO_PORT_GAIN_LOG "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Tracing><OutputFile>cyclonedds_liveliness_tests.${CYCLONEDDS_DOMAIN_ID}.${CYCLONEDDS_PID}.log</OutputFile><Verbosity>finest</Verbosity></Tracing><Discovery><ExternalDomainId>0</ExternalDomainId></Discovery>"
 
-uint32_t g_topic_nr = 0;
 static dds_entity_t g_pub_domain = 0;
 static dds_entity_t g_pub_participant = 0;
 static dds_entity_t g_pub_publisher = 0;
@@ -43,15 +42,6 @@ static dds_entity_t g_sub_domain = 0;
 static dds_entity_t g_sub_participant = 0;
 static dds_entity_t g_sub_subscriber = 0;
 
-static char *create_topic_name(const char *prefix, uint32_t nr, char *name, size_t size)
-{
-  /* Get unique g_topic name. */
-  ddsrt_pid_t pid = ddsrt_getpid();
-  ddsrt_tid_t tid = ddsrt_gettid();
-  (void)snprintf(name, size, "%s%d_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, pid, tid);
-  return name;
-}
-
 static void liveliness_init(void)
 {
   /* Domains for pub and sub use a different domain id, but the portgain setting
@@ -179,7 +169,7 @@ static void test_pmd_count(dds_liveliness_kind_t kind, uint32_t ldur, double mul
     dds_sleepfor(DDS_MSECS(50));
 
   /* topics */
-  create_topic_name("ddsc_liveliness_pmd_count", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name("ddsc_liveliness_pmd_count", name, sizeof name);
   CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
   if (remote_reader)
     CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
@@ -272,7 +262,7 @@ static void test_expire_liveliness_kinds(uint32_t ldur, double mult, uint32_t wr
            ldur, mult, wr_cnt_auto, wr_cnt_man_pp, wr_cnt_man_tp, remote_reader ? "remote" : "local");
 
     /* topics */
-    create_topic_name("ddsc_liveliness_expire_kinds", g_topic_nr++, name, sizeof name);
+    create_unique_topic_name("ddsc_liveliness_expire_kinds", name, sizeof name);
     CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
     if (remote_reader)
       CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
@@ -428,7 +418,7 @@ CU_Test(ddsc_liveliness, lease_duration, .init = liveliness_init, .fini = liveli
   uint32_t n;
 
   /* topics */
-  create_topic_name("ddsc_liveliness_ldur", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name("ddsc_liveliness_ldur", name, sizeof name);
   CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
   CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
 
@@ -489,7 +479,7 @@ static void test_lease_duration_pwr(bool remote_reader)
   printf("running test lease_duration_pwr: %s reader\n", remote_reader ? "remote" : "local");
 
   /* topics */
-  create_topic_name("ddsc_liveliness_ldurpwr", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name("ddsc_liveliness_ldurpwr", name, sizeof name);
   CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
   if (remote_reader)
     CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
@@ -571,7 +561,7 @@ static void test_create_delete_writer_stress(bool remote_reader)
   printf("running test create_delete_writer_stress: %s reader\n", remote_reader ? "remote" : "local");
 
   /* topics */
-  create_topic_name("ddsc_liveliness_wr_stress", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name("ddsc_liveliness_wr_stress", name, sizeof name);
   CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
   if (remote_reader)
     CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
@@ -672,7 +662,7 @@ static void test_status_counts(bool remote_reader)
   printf("running test status_counts: %s reader\n", remote_reader ? "remote" : "local");
 
   /* topics */
-  create_topic_name("ddsc_liveliness_status_counts", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name("ddsc_liveliness_status_counts", name, sizeof name);
   CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
   if (remote_reader)
     CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
@@ -772,7 +762,7 @@ static void test_assert_liveliness(uint32_t wr_cnt_auto, uint32_t wr_cnt_man_pp,
            wr_cnt_auto, wr_cnt_man_pp, wr_cnt_man_tp, ldur, remote_reader ? "remote" : "local");
 
     /* topics */
-    create_topic_name("ddsc_liveliness_assert", g_topic_nr++, name, sizeof name);
+    create_unique_topic_name("ddsc_liveliness_assert", name, sizeof name);
     CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
     if (remote_reader)
       CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
@@ -1018,7 +1008,7 @@ static void lease_duration_zero_or_one_impl (dds_duration_t sleep, dds_livelines
   dds_qset_reliability(qos, DDS_RELIABILITY_RELIABLE, DDS_INFINITY);
   dds_qset_history(qos, DDS_HISTORY_KEEP_ALL, 0);
 
-  create_topic_name("ddsc_liveliness_lease_duration_zero", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name("ddsc_liveliness_lease_duration_zero", name, sizeof name);
   pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, qos, NULL);
   CU_ASSERT_FATAL(pub_topic > 0);
   if (remote_reader)
diff --git a/src/core/ddsc/tests/loan.c b/src/core/ddsc/tests/loan.c
new file mode 100644
index 0000000..5e12d84
--- /dev/null
+++ b/src/core/ddsc/tests/loan.c
@@ -0,0 +1,321 @@
+/*
+ * Copyright(c) 2006 to 2020 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#include <stdio.h>
+#include "dds/dds.h"
+#include "test_common.h"
+
+static dds_entity_t participant, topic, reader, writer, read_condition, read_condition_unread;
+
+static void create_entities (void)
+{
+  char topicname[100];
+  struct dds_qos *qos;
+
+  create_unique_topic_name ("ddsc_return_loan_test", topicname, sizeof topicname);
+  participant = dds_create_participant (DDS_DOMAIN_DEFAULT, NULL, NULL);
+  CU_ASSERT_FATAL (participant > 0);
+
+  qos = dds_create_qos ();
+  dds_qset_reliability (qos, DDS_RELIABILITY_RELIABLE, 0);
+  dds_qset_history (qos, DDS_HISTORY_KEEP_ALL, 1);
+  topic = dds_create_topic (participant, &RoundTripModule_DataType_desc, topicname, qos, NULL);
+  CU_ASSERT_FATAL (topic > 0);
+  dds_delete_qos (qos);
+
+  writer = dds_create_writer (participant, topic, NULL, NULL);
+  CU_ASSERT_FATAL (writer > 0);
+  reader = dds_create_reader (participant, topic, NULL, NULL);
+  CU_ASSERT_FATAL (reader > 0);
+  read_condition = dds_create_readcondition (reader, DDS_ANY_STATE);
+  CU_ASSERT_FATAL (read_condition > 0);
+  read_condition_unread = dds_create_readcondition (reader, DDS_ANY_INSTANCE_STATE | DDS_ANY_VIEW_STATE | DDS_NOT_READ_SAMPLE_STATE);
+  CU_ASSERT_FATAL (read_condition > 0);
+}
+
+static void delete_entities (void)
+{
+  dds_return_t result;
+  result = dds_delete (participant);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+}
+
+CU_Test (ddsc_loan, bad_params, .init = create_entities, .fini = delete_entities)
+{
+  dds_return_t result;
+
+  /* buf = NULL */
+  result = dds_return_loan (reader, NULL, -1);
+  CU_ASSERT (result == DDS_RETCODE_BAD_PARAMETER);
+  result = dds_return_loan (reader, NULL, 0);
+  CU_ASSERT (result == DDS_RETCODE_BAD_PARAMETER);
+  result = dds_return_loan (reader, NULL, 1);
+  CU_ASSERT (result == DDS_RETCODE_BAD_PARAMETER);
+
+  /* buf[0] = NULL, size > 0 */
+  void *buf = NULL;
+  result = dds_return_loan (reader, &buf, 1);
+  CU_ASSERT (result == DDS_RETCODE_BAD_PARAMETER);
+  /* buf[0] != NULL, size <= 0 */
+  char dummy = 0;
+  buf = &dummy;
+  result = dds_return_loan (reader, &buf, 0);
+  CU_ASSERT (result == DDS_RETCODE_BAD_PARAMETER);
+  result = dds_return_loan (reader, &buf, -1);
+  CU_ASSERT (result == DDS_RETCODE_BAD_PARAMETER);
+
+  /* not a reader or condition (checking only the ones we have at hand) */
+  result = dds_return_loan (participant, &buf, 1);
+  CU_ASSERT (result == DDS_RETCODE_ILLEGAL_OPERATION);
+  result = dds_return_loan (topic, &buf, 1);
+  CU_ASSERT (result == DDS_RETCODE_ILLEGAL_OPERATION);
+}
+
+CU_Test (ddsc_loan, success, .init = create_entities, .fini = delete_entities)
+{
+  const RoundTripModule_DataType s = {
+    .payload = {
+      ._length = 1,
+      ._buffer = (uint8_t[]) { 'a' }
+    }
+  };
+  const unsigned char zeros[3 * sizeof (s)] = { 0 };
+  dds_return_t result;
+  for (size_t i = 0; i < 3; i++)
+  {
+    result = dds_write (writer, &s);
+    CU_ASSERT_FATAL (result == 0);
+  }
+
+  /* rely on things like address sanitizer, valgrind for detecting double frees and leaks */
+  int32_t n;
+  void *ptrs[3] = { NULL };
+  void *ptr0copy, *ptr1copy;
+  dds_sample_info_t si[3];
+
+  /* read 1, return: this should cause memory to be allocated for 1 sample only */
+  n = dds_read (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] != NULL && ptrs[1] == NULL);
+  ptr0copy = ptrs[0];
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+  /* return resets buf[0] (so that it picks up the loan the next time) and zeros the data */
+  CU_ASSERT_FATAL (ptrs[0] == NULL);
+  CU_ASSERT_FATAL (memcmp (ptr0copy, zeros, sizeof (s)) == 0);
+
+  /* read 3, return: should work fine, causes realloc */
+  n = dds_read (reader, ptrs, si, 3, 3);
+  CU_ASSERT_FATAL (n == 3);
+  CU_ASSERT_FATAL (ptrs[0] != NULL && ptrs[1] != NULL && ptrs[2] != NULL);
+  ptr0copy = ptrs[0];
+  ptr1copy = ptrs[1];
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+  CU_ASSERT_FATAL (ptrs[0] == NULL);
+  CU_ASSERT_FATAL (memcmp (ptr0copy, zeros, 3 * sizeof (s)) == 0);
+
+  /* read 1 using loan, expecting to get the same address (no realloc needed), defer return.
+     Expect ptrs[1] to remain unchanged, although that probably is really an implementation
+     detail rather than something one might want to rely on */
+  n = dds_read (read_condition, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == ptr1copy);
+
+  /* read 3, letting read allocate */
+  int32_t n2;
+  void *ptrs2[3] = { NULL };
+  n2 = dds_read (read_condition, ptrs2, si, 3, 3);
+  CU_ASSERT_FATAL (n2 == 3);
+  CU_ASSERT_FATAL (ptrs2[0] != NULL && ptrs2[1] != NULL && ptrs2[2] != NULL);
+  CU_ASSERT_FATAL (ptrs2[0] != ptrs[0]);
+
+  /* contents of first sample should be the same; the point of comparing them
+     is that valgrind/address sanitizer will get angry with us if one of them
+     has been freed; can't use memcmp because the sequence buffers should be
+     at different addresses */
+  {
+    const struct RoundTripModule_DataType *a = ptrs[0];
+    const struct RoundTripModule_DataType *b = ptrs2[0];
+    CU_ASSERT_FATAL (a->payload._length == b->payload._length);
+    CU_ASSERT_FATAL (a->payload._buffer != b->payload._buffer);
+    CU_ASSERT_FATAL (a->payload._buffer[0] == b->payload._buffer[0]);
+  }
+
+  /* return loan -- to be freed when we delete the reader */
+  result = dds_return_loan (read_condition, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+  CU_ASSERT_FATAL (ptrs[0] == NULL);
+
+  /* use "dds_return_loan" to free the second result immediately, there's no
+     easy way to check this happens short of using a custom sertopic */
+  ptr0copy = ptrs2[0];
+  result = dds_return_loan (read_condition, ptrs2, n2);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+  CU_ASSERT_FATAL (ptrs2[0] == NULL);
+
+  //This should be a use-after-free
+  //CU_ASSERT_FATAL (memcmp (ptr0copy, zeros, sizeof (s)) == 0);
+}
+
+CU_Test (ddsc_loan, take_cleanup, .init = create_entities, .fini = delete_entities)
+{
+  const RoundTripModule_DataType s = {
+    .payload = {
+      ._length = 1,
+      ._buffer = (uint8_t[]) { 'a' }
+    }
+  };
+  dds_return_t result;
+
+  /* rely on things like address sanitizer, valgrind for detecting double frees and leaks */
+  int32_t n;
+  void *ptrs[3] = { NULL };
+  void *ptr0copy;
+  dds_sample_info_t si[3];
+
+  /* take 1 from an empty reader: this should cause memory to be allocated for
+     1 sample only, be stored as the loan, but not become visisble to the
+     application */
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 0);
+  CU_ASSERT_FATAL (ptrs[0] == NULL && ptrs[1] == NULL);
+
+  /* take 1 that's present: allocates a loan  */
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] != NULL && ptrs[1] == NULL);
+  ptr0copy = ptrs[0];
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+
+  /* if it really got handled as a loan, the same address must come out again
+     (rely on address sanitizer allocating at a different address each time) */
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == NULL);
+  ptr0copy = ptrs[0];
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+
+  /* take that fails (for lack of data in this case) must reuse the loan, but
+     hand it back and restore the null pointer */
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 0);
+  CU_ASSERT_FATAL (ptrs[0] == NULL && ptrs[1] == NULL);
+
+  /* take that succeeds again must therefore still be using the same address */
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == NULL);
+
+  /* take that fails (with the loan still out) must allocate new memory and
+     free it */
+  int32_t n2;
+  void *ptrs2[3] = { NULL };
+  n2 = dds_take (reader, ptrs2, si, 1, 1);
+  CU_ASSERT_FATAL (n2 == 0);
+  CU_ASSERT_FATAL (ptrs2[0] == NULL && ptrs2[1] == NULL);
+
+  /* return the loan and the next take should reuse the memory */
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == NULL);
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+}
+
+CU_Test (ddsc_loan, read_cleanup, .init = create_entities, .fini = delete_entities)
+{
+  const RoundTripModule_DataType s = {
+    .payload = {
+      ._length = 1,
+      ._buffer = (uint8_t[]) { 'a' }
+    }
+  };
+  dds_return_t result;
+
+  /* rely on things like address sanitizer, valgrind for detecting double frees and leaks */
+  int32_t n;
+  void *ptrs[3] = { NULL };
+  void *ptr0copy;
+  dds_sample_info_t si[3];
+
+  /* read 1 from an empty reader: this should cause memory to be allocated for
+     1 sample only, be stored as the loan, but not become visisble to the
+     application */
+  n = dds_read (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 0);
+  CU_ASSERT_FATAL (ptrs[0] == NULL && ptrs[1] == NULL);
+
+  /* read 1 that's present: allocates a loan  */
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_take (reader, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] != NULL && ptrs[1] == NULL);
+  ptr0copy = ptrs[0];
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+
+  /* if it really got handled as a loan, the same address must come out again
+     (rely on address sanitizer allocating at a different address each time) */
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_read (read_condition_unread, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == NULL);
+  ptr0copy = ptrs[0];
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+
+  /* take that fails (for lack of data in this case) must reuse the loan, but
+     hand it back and restore the null pointer */
+  n = dds_read (read_condition_unread, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 0);
+  CU_ASSERT_FATAL (ptrs[0] == NULL && ptrs[1] == NULL);
+
+  /* take that succeeds again must therefore still be using the same address */
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_read (read_condition_unread, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == NULL);
+
+  /* take that fails (with the loan still out) must allocate new memory and
+     free it */
+  int32_t n2;
+  void *ptrs2[3] = { NULL };
+  n2 = dds_read (read_condition_unread, ptrs2, si, 1, 1);
+  CU_ASSERT_FATAL (n2 == 0);
+  CU_ASSERT_FATAL (ptrs2[0] == NULL && ptrs2[1] == NULL);
+
+  /* return the loan and the next take should reuse the memory */
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+  result = dds_write (writer, &s);
+  CU_ASSERT_FATAL (result == 0);
+  n = dds_read (read_condition_unread, ptrs, si, 1, 1);
+  CU_ASSERT_FATAL (n == 1);
+  CU_ASSERT_FATAL (ptrs[0] == ptr0copy && ptrs[1] == NULL);
+  result = dds_return_loan (reader, ptrs, n);
+  CU_ASSERT_FATAL (result == DDS_RETCODE_OK);
+}
diff --git a/src/core/ddsc/tests/multi_sertopic.c b/src/core/ddsc/tests/multi_sertopic.c
index 1bbdfbf..f66b89b 100644
--- a/src/core/ddsc/tests/multi_sertopic.c
+++ b/src/core/ddsc/tests/multi_sertopic.c
@@ -13,8 +13,6 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
 #include "config_env.h"
 
 #include "dds/version.h"
@@ -30,6 +28,8 @@
 #include "dds/ddsrt/atomics.h"
 #include "dds/ddsrt/time.h"
 
+#include "test_common.h"
+
 #define DDS_DOMAINID_PUB 0
 #define DDS_DOMAINID_SUB 1
 #define DDS_CONFIG_NO_PORT_GAIN "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Discovery><ExternalDomainId>0</ExternalDomainId></Discovery>"
@@ -167,7 +167,6 @@ static const dds_topic_descriptor_t type_ary2_desc =
   .m_meta = "" /* this is on its way out anyway */
 };
 
-static uint32_t g_topic_nr = 0;
 static dds_entity_t g_pub_domain = 0;
 static dds_entity_t g_pub_participant = 0;
 static dds_entity_t g_pub_publisher = 0;
@@ -176,15 +175,6 @@ static dds_entity_t g_sub_domain = 0;
 static dds_entity_t g_sub_participant = 0;
 static dds_entity_t g_sub_subscriber = 0;
 
-static char *create_topic_name (const char *prefix, uint32_t nr, char *name, size_t size)
-{
-  /* Get unique g_topic name. */
-  ddsrt_pid_t pid = ddsrt_getpid();
-  ddsrt_tid_t tid = ddsrt_gettid();
-  (void) snprintf (name, size, "%s%d_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, pid, tid);
-  return name;
-}
-
 static void multi_sertopic_init (void)
 {
   /* Domains for pub and sub use a different domain id, but the portgain setting
@@ -366,7 +356,7 @@ static void ddsc_multi_sertopic_impl (dds_entity_t pp_pub, dds_entity_t pp_sub,
   dds_qset_destination_order (qos, DDS_DESTINATIONORDER_BY_SOURCE_TIMESTAMP);
   dds_qset_history (qos, DDS_HISTORY_KEEP_ALL, 0);
 
-  create_topic_name ("ddsc_multi_sertopic_lease_duration_zero", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name ("ddsc_multi_sertopic_lease_duration_zero", name, sizeof name);
 
   for (size_t i = 0; i < sizeof (pub_topics) / sizeof (pub_topics[0]); i++)
   {
diff --git a/src/core/ddsc/tests/querycondition.c b/src/core/ddsc/tests/querycondition.c
index d1afbf5..960437e 100644
--- a/src/core/ddsc/tests/querycondition.c
+++ b/src/core/ddsc/tests/querycondition.c
@@ -12,13 +12,12 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -68,16 +67,6 @@ filter_mod2(const void * sample)
     return (s->long_1 % 2 == 0);
 }
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 querycondition_init_hdepth(int hdepth)
 {
@@ -93,7 +82,7 @@ querycondition_init_hdepth(int hdepth)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_querycondition_test", name, sizeof name), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_querycondition_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a reader that keeps last sample of all instances. */
diff --git a/src/core/ddsc/tests/read_instance.c b/src/core/ddsc/tests/read_instance.c
index db46759..4c85e1b 100644
--- a/src/core/ddsc/tests/read_instance.c
+++ b/src/core/ddsc/tests/read_instance.c
@@ -13,13 +13,11 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "Space.h"
-#include "RoundTrip.h"
-#include "CUnit/Theory.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -67,16 +65,6 @@ filter_mod2(const void * sample)
     return (s->long_2 % 2 == 0);
 }
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 read_instance_init(void)
 {
@@ -101,7 +89,7 @@ read_instance_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_read_instance_test", name, sizeof name), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_read_instance_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a writer that will not automatically dispose unregistered samples. */
diff --git a/src/core/ddsc/tests/readcondition.c b/src/core/ddsc/tests/readcondition.c
index 4566d0c..af180a9 100644
--- a/src/core/ddsc/tests/readcondition.c
+++ b/src/core/ddsc/tests/readcondition.c
@@ -10,14 +10,12 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds/dds.h"
-#include "CUnit/Test.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -60,16 +58,6 @@ static void*             g_samples[MAX_SAMPLES];
 static Space_Type1       g_data[MAX_SAMPLES];
 static dds_sample_info_t g_info[MAX_SAMPLES];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 readcondition_init(void)
 {
@@ -85,7 +73,7 @@ readcondition_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_readcondition_test", name, 100), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_readcondition_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a reader that keeps last sample of all instances. */
diff --git a/src/core/ddsc/tests/reader.c b/src/core/ddsc/tests/reader.c
index 97f8131..ca5d9fe 100644
--- a/src/core/ddsc/tests/reader.c
+++ b/src/core/ddsc/tests/reader.c
@@ -13,14 +13,12 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "Space.h"
-#include "RoundTrip.h"
-#include "CUnit/Theory.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -64,16 +62,6 @@ static void*              g_samples[MAX_SAMPLES];
 static Space_Type1        g_data[MAX_SAMPLES];
 static dds_sample_info_t  g_info[MAX_SAMPLES];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 reader_init(void)
 {
@@ -94,7 +82,7 @@ reader_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_reader_test", name, sizeof name), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_reader_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a reader that keeps last sample of all instances. */
@@ -306,7 +294,7 @@ CU_Test(ddsc_reader_create, participant_mismatch)
     sub1 = dds_create_subscriber(par1, NULL, NULL);
     CU_ASSERT_FATAL(sub1 > 0);
 
-    top2 = dds_create_topic(par2, &Space_Type1_desc, create_topic_name("ddsc_reader_participant_mismatch", name, sizeof name), NULL, NULL);
+    top2 = dds_create_topic(par2, &Space_Type1_desc, create_unique_topic_name("ddsc_reader_participant_mismatch", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(top2 > 0);
 
     /* Create reader with participant mismatch. */
@@ -2512,7 +2500,7 @@ CU_Test(ddsc_take_mask, take_instance_last_sample)
     CU_ASSERT_FATAL(g_participant > 0);
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_reader_test", name, 100), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_reader_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
     g_reader = dds_create_reader(g_participant, g_topic, g_qos, NULL);
     CU_ASSERT_FATAL(g_reader > 0);
diff --git a/src/core/ddsc/tests/reader_iterator.c b/src/core/ddsc/tests/reader_iterator.c
index a714a67..df1e4c1 100644
--- a/src/core/ddsc/tests/reader_iterator.c
+++ b/src/core/ddsc/tests/reader_iterator.c
@@ -13,13 +13,11 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "Space.h"
-#include "RoundTrip.h"
-#include "CUnit/Theory.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -83,16 +81,6 @@ static void*              g_samples[MAX_SAMPLES];
 static Space_Type1        g_data[MAX_SAMPLES];
 static dds_sample_info_t  g_info[MAX_SAMPLES];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static bool
 filter_init(const void * sample)
 {
@@ -140,7 +128,7 @@ reader_iterator_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_read_iterator_test", name, sizeof name), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_read_iterator_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a writer that will not automatically dispose unregistered samples. */
@@ -459,7 +447,8 @@ CU_Test(ddsc_read_next_wl, reader, .init=reader_iterator_init, .fini=reader_iter
     CU_ASSERT_EQUAL_FATAL(cnt, RDR_NOT_READ_CNT);
     CU_ASSERT_EQUAL_FATAL(cntinv, RDR_INV_READ_CNT);
 
-    ret = dds_return_loan(g_reader, g_loans, ret);
+    /* return_loan 3rd arg should be in [highest count ever returned, read limit] */
+    ret = dds_return_loan(g_reader, g_loans, 1);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
 
     /* All samples should still be available. */
@@ -683,7 +672,8 @@ CU_Test(ddsc_take_next_wl, reader, .init=reader_iterator_init, .fini=reader_iter
     CU_ASSERT_EQUAL_FATAL(cnt, RDR_NOT_READ_CNT);
     CU_ASSERT_EQUAL_FATAL(cntinv, RDR_INV_READ_CNT);
 
-    ret = dds_return_loan(g_reader, g_loans, ret);
+    /* return_loan 3rd arg should be in [highest count ever returned, read limit] */
+    ret = dds_return_loan(g_reader, g_loans, 1);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
 
     /* All samples should still be available. */
diff --git a/src/core/ddsc/tests/register.c b/src/core/ddsc/tests/register.c
index b04d35f..05aec4f 100644
--- a/src/core/ddsc/tests/register.c
+++ b/src/core/ddsc/tests/register.c
@@ -12,14 +12,12 @@
 #include <assert.h>
 
 #include "dds/dds.h"
-#include "CUnit/Test.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -41,16 +39,6 @@ static dds_time_t   g_present     = 0;
 static void*             g_samples[MAX_SAMPLES];
 static Space_Type1       g_data[MAX_SAMPLES];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 registering_init(void)
 {
@@ -69,7 +57,7 @@ registering_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_registering_test", name, sizeof name), qos, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_registering_test", name, sizeof name), qos, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a reader that keeps one sample on three instances. */
diff --git a/src/core/ddsc/tests/return_loan.c b/src/core/ddsc/tests/return_loan.c
deleted file mode 100644
index 812e024..0000000
--- a/src/core/ddsc/tests/return_loan.c
+++ /dev/null
@@ -1,140 +0,0 @@
-/*
- * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
- * v. 1.0 which is available at
- * http://www.eclipse.org/org/documents/edl-v10.php.
- *
- * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
- */
-#include "dds/dds.h"
-#include "RoundTrip.h"
-
-#include <stdio.h>
-#include "CUnit/Test.h"
-
-static dds_entity_t participant = 0, topic = 0, reader = 0, read_condition = 0;
-
-static void create_entities(void)
-{
-    participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
-    CU_ASSERT_FATAL(participant > 0);
-
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, "ddsc_reader_return_loan_RoundTrip", NULL, NULL);
-    CU_ASSERT_FATAL(topic > 0);
-
-    reader = dds_create_reader(participant, topic, NULL, NULL);
-    CU_ASSERT_FATAL(reader > 0);
-
-    read_condition = dds_create_readcondition(reader, DDS_ANY_STATE);
-    CU_ASSERT_FATAL(read_condition > 0);
-}
-
-static void delete_entities(void)
-{
-    dds_return_t result;
-    result = dds_delete(participant);
-    CU_ASSERT_EQUAL_FATAL(result, DDS_RETCODE_OK);
-    dds_delete(read_condition);
-}
-
-static void** create_loan_buf(size_t sz, bool empty)
-{
-    size_t i;
-    void **buf = NULL;
-    buf = dds_alloc(sz * sizeof(*buf));
-    for (i = 0; i < sz; i++) {
-        buf[i] = dds_alloc(sizeof(RoundTripModule_DataType));
-        if (empty) {
-            memset(buf[i], 0, sizeof(RoundTripModule_DataType));
-        } else {
-            RoundTripModule_DataType *s = buf[i];
-            s->payload._maximum = 0;
-            s->payload._length = 25;
-            s->payload._buffer = dds_alloc(25);
-            memset(s->payload._buffer, 'z', 25);
-            s->payload._release = true;
-        }
-    }
-    return buf;
-}
-
-static void delete_loan_buf(void **buf, size_t sz, bool empty)
-{
-    size_t i;
-    for (i = 0; i < sz; i++) {
-        RoundTripModule_DataType *s = buf[i];
-        if (!empty) {
-            CU_ASSERT(s->payload._length > 0);
-            if (s->payload._length > 0) {
-                /* Freed by a successful dds_return_loan */
-                dds_free(s->payload._buffer);
-            }
-        }
-        /* dds_return_loan only free's sample contents */
-        dds_free(s);
-    }
-    dds_free(buf);
-}
-
-/* Verify DDS_RETCODE_BAD_PARAMETER is returned */
-CU_Test(ddsc_reader, return_loan_bad_params, .init = create_entities, .fini = delete_entities)
-{
-    dds_return_t result;
-    void **buf = NULL;
-
-    result = dds_return_loan(reader, NULL, 0);
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_BAD_PARAMETER);
-
-#ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable: 6387)
-#endif
-    result = dds_return_loan(reader, buf, 10);
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_BAD_PARAMETER);
-
-    buf = create_loan_buf(10, false);
-#ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable: 28020)
-#endif
-    result = dds_return_loan(0, buf, 10);
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_BAD_PARAMETER);
-
-    result = dds_return_loan(participant, buf, 0);
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_ILLEGAL_OPERATION);
-
-    delete_loan_buf(buf, 10, false);
-}
-
-/* Verify DDS_RETCODE_OK is returned */
-CU_Test(ddsc_reader, return_loan_success, .init = create_entities, .fini = delete_entities)
-{
-    void **buf;
-    void *buf2 = NULL;
-    dds_return_t result;
-
-    buf = create_loan_buf(10, false);
-    result = dds_return_loan(reader, buf, 10);
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_OK);
-
-    result = dds_return_loan(reader, &buf2, 0);
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_OK);
-    delete_loan_buf(buf, 10, true);
-
-    buf = create_loan_buf(10, false);
-    result = dds_return_loan(read_condition, buf, 10);
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_OK);
-
-    result = dds_return_loan(read_condition, &buf2, 0);
-    CU_ASSERT_EQUAL(result, DDS_RETCODE_OK);
-    delete_loan_buf(buf, 10, true);
-}
diff --git a/src/core/ddsc/tests/take_instance.c b/src/core/ddsc/tests/take_instance.c
index e8cba48..809ffae 100644
--- a/src/core/ddsc/tests/take_instance.c
+++ b/src/core/ddsc/tests/take_instance.c
@@ -13,13 +13,11 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "Space.h"
-#include "RoundTrip.h"
-#include "CUnit/Theory.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -67,16 +65,6 @@ filter_mod2(const void * sample)
     return (s->long_2 % 2 == 0);
 }
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 take_instance_init(void)
 {
@@ -101,7 +89,7 @@ take_instance_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_take_instance_test", name, sizeof name), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_take_instance_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a writer that will not automatically dispose unregistered samples. */
diff --git a/src/core/ddsc/tests/test-common.c b/src/core/ddsc/tests/test-common.c
deleted file mode 100644
index 44b846f..0000000
--- a/src/core/ddsc/tests/test-common.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v. 2.0 which is available at
- * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
- * v. 1.0 which is available at
- * http://www.eclipse.org/org/documents/edl-v10.php.
- *
- * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
- */
-#include "dds/dds.h"
-
-const char*
-entity_kind_str(dds_entity_t ent) {
-    if(ent <= 0) {
-        return "(ERROR)";
-    }
-    switch(ent & DDS_ENTITY_KIND_MASK) {
-        case DDS_KIND_TOPIC:        return "Topic";
-        case DDS_KIND_PARTICIPANT:  return "Participant";
-        case DDS_KIND_READER:       return "Reader";
-        case DDS_KIND_WRITER:       return "Writer";
-        case DDS_KIND_SUBSCRIBER:   return "Subscriber";
-        case DDS_KIND_PUBLISHER:    return "Publisher";
-        case DDS_KIND_COND_READ:    return "ReadCondition";
-        case DDS_KIND_COND_QUERY:   return "QueryCondition";
-        case DDS_KIND_WAITSET:      return "WaitSet";
-        default:                    return "(INVALID_ENTITY)";
-    }
-}
diff --git a/src/core/ddsc/tests/test_common.c b/src/core/ddsc/tests/test_common.c
new file mode 100644
index 0000000..531322b
--- /dev/null
+++ b/src/core/ddsc/tests/test_common.c
@@ -0,0 +1,26 @@
+/*
+ * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#include "dds/dds.h"
+#include "dds/ddsrt/atomics.h"
+#include "dds/ddsrt/process.h"
+#include "dds/ddsrt/threads.h"
+#include "test_common.h"
+
+char *create_unique_topic_name (const char *prefix, char *name, size_t size)
+{
+  static ddsrt_atomic_uint32_t count = DDSRT_ATOMIC_UINT64_INIT (0);
+  const ddsrt_pid_t pid = ddsrt_getpid();
+  const ddsrt_tid_t tid = ddsrt_gettid();
+  const uint32_t nr = ddsrt_atomic_inc32_nv (&count);
+  (void) snprintf (name, size, "%s%"PRIu32"_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, pid, tid);
+  return name;
+}
diff --git a/src/core/ddsc/tests/test-common.h b/src/core/ddsc/tests/test_common.h
similarity index 58%
rename from src/core/ddsc/tests/test-common.h
rename to src/core/ddsc/tests/test_common.h
index 917e4b9..6672d93 100644
--- a/src/core/ddsc/tests/test-common.h
+++ b/src/core/ddsc/tests/test_common.h
@@ -1,5 +1,5 @@
 /*
- * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
+ * Copyright(c) 2006 to 2020 ADLINK Technology Limited and others
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -12,6 +12,16 @@
 #ifndef _TEST_COMMON_H_
 #define _TEST_COMMON_H_
 
-const char *entity_kind_str(dds_entity_t ent);
+#include <stdint.h>
+#include <stddef.h>
+
+#include "CUnit/Test.h"
+#include "CUnit/Theory.h"
+
+#include "Space.h"
+#include "RoundTrip.h"
+
+/* Get unique g_topic name on each invocation. */
+char *create_unique_topic_name (const char *prefix, char *name, size_t size);
 
 #endif /* _TEST_COMMON_H_ */
diff --git a/src/core/ddsc/tests/topic.c b/src/core/ddsc/tests/topic.c
index 813d77f..013bf22 100644
--- a/src/core/ddsc/tests/topic.c
+++ b/src/core/ddsc/tests/topic.c
@@ -10,13 +10,12 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds/dds.h"
-#include "RoundTrip.h"
-#include "CUnit/Theory.h"
-
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -36,21 +35,11 @@ char g_topicRtmAddressName[MAX_NAME_SIZE];
 char g_topicRtmDataTypeName[MAX_NAME_SIZE];
 char g_nameBuffer[MAX_NAME_SIZE];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 ddsc_topic_init(void)
 {
-    create_topic_name("ddsc_topic_test_rtm_address",  g_topicRtmAddressName,  MAX_NAME_SIZE);
-    create_topic_name("ddsc_topic_test_rtm_datatype", g_topicRtmDataTypeName, MAX_NAME_SIZE);
+    create_unique_topic_name("ddsc_topic_test_rtm_address",  g_topicRtmAddressName,  MAX_NAME_SIZE);
+    create_unique_topic_name("ddsc_topic_test_rtm_datatype", g_topicRtmDataTypeName, MAX_NAME_SIZE);
 
     g_participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(g_participant > 0);
diff --git a/src/core/ddsc/tests/unregister.c b/src/core/ddsc/tests/unregister.c
index 538c661..e3dcf00 100644
--- a/src/core/ddsc/tests/unregister.c
+++ b/src/core/ddsc/tests/unregister.c
@@ -13,13 +13,11 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Test.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Test fixtures
@@ -41,16 +39,6 @@ static void*             g_samples[MAX_SAMPLES];
 static Space_Type1       g_data[MAX_SAMPLES];
 static dds_sample_info_t g_info[MAX_SAMPLES];
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
 static void
 unregistering_init(void)
 {
@@ -69,7 +57,7 @@ unregistering_init(void)
     g_waitset = dds_create_waitset(g_participant);
     CU_ASSERT_FATAL(g_waitset > 0);
 
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_unregistering_test", name, 100), qos, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_unregistering_test", name, 100), qos, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
 
     /* Create a reader that keeps one sample on three instances. */
@@ -616,7 +604,7 @@ CU_Test(ddsc_unregister_instance_ih_ts, unregistering_instance)
     /* Create a writer that WILL automatically dispose unregistered samples. */
     g_participant = dds_create_participant(DDS_DOMAIN_DEFAULT, NULL, NULL);
     CU_ASSERT_FATAL(g_participant > 0);
-    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_topic_name("ddsc_unregistering_instance_test", name, 100), NULL, NULL);
+    g_topic = dds_create_topic(g_participant, &Space_Type1_desc, create_unique_topic_name("ddsc_unregistering_instance_test", name, 100), NULL, NULL);
     CU_ASSERT_FATAL(g_topic > 0);
     g_writer = dds_create_writer(g_participant, g_topic, NULL, NULL);
     CU_ASSERT_FATAL(g_writer > 0);
diff --git a/src/core/ddsc/tests/unsupported.c b/src/core/ddsc/tests/unsupported.c
index 9c538ce..6ec39cc 100644
--- a/src/core/ddsc/tests/unsupported.c
+++ b/src/core/ddsc/tests/unsupported.c
@@ -15,7 +15,7 @@
 #include "dds/dds.h"
 #include "RoundTrip.h"
 
-#include "test-common.h"
+#include "test_common.h"
 
 static dds_entity_t e[8];
 
diff --git a/src/core/ddsc/tests/waitset.c b/src/core/ddsc/tests/waitset.c
index 1f6e0b5..0f69025 100644
--- a/src/core/ddsc/tests/waitset.c
+++ b/src/core/ddsc/tests/waitset.c
@@ -13,9 +13,6 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "RoundTrip.h"
-
 #include "dds/ddsrt/cdtors.h"
 #include "dds/ddsrt/misc.h"
 #include "dds/ddsrt/process.h"
@@ -23,6 +20,8 @@
 #include "dds/ddsrt/atomics.h"
 #include "dds/ddsrt/time.h"
 
+#include "test_common.h"
+
 /**************************************************************************************************
  *
  * Some thread related convenience stuff.
@@ -63,17 +62,6 @@ static dds_entity_t subscriber  = 0;
 static dds_entity_t readcond    = 0;
 
 
-static char*
-create_topic_name(const char *prefix, char *name, size_t size)
-{
-    /* Get semi random g_topic name. */
-    ddsrt_pid_t pid = ddsrt_getpid();
-    ddsrt_tid_t tid = ddsrt_gettid();
-    (void) snprintf(name, size, "%s_pid%"PRIdPID"_tid%"PRIdTID"", prefix, pid, tid);
-    return name;
-}
-
-
 static void
 ddsc_waitset_basic_init(void)
 {
@@ -109,7 +97,7 @@ ddsc_waitset_init(void)
     subscriber = dds_create_subscriber(participant, NULL, NULL);
     CU_ASSERT_FATAL(subscriber >  0);
 
-    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_topic_name("ddsc_waitset_test", name, sizeof name), NULL, NULL);
+    topic = dds_create_topic(participant, &RoundTripModule_DataType_desc, create_unique_topic_name("ddsc_waitset_test", name, sizeof name), NULL, NULL);
     CU_ASSERT_FATAL(topic >  0);
 
     reader = dds_create_reader(subscriber, topic, NULL, NULL);
diff --git a/src/core/ddsc/tests/whc.c b/src/core/ddsc/tests/whc.c
index cdade5e..93fda9e 100644
--- a/src/core/ddsc/tests/whc.c
+++ b/src/core/ddsc/tests/whc.c
@@ -13,9 +13,6 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "Space.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 #include "dds/ddsrt/environ.h"
@@ -24,6 +21,8 @@
 #include "dds/ddsi/q_whc.h"
 #include "dds__entity.h"
 
+#include "test_common.h"
+
 #define DDS_DOMAINID_PUB 0
 #define DDS_DOMAINID_SUB 1
 #define DDS_CONFIG_NO_PORT_GAIN "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Discovery><ExternalDomainId>0</ExternalDomainId></Discovery>"
@@ -32,7 +31,6 @@
 #define SAMPLE_COUNT 5
 #define DEADLINE_DURATION DDS_MSECS(1)
 
-static uint32_t g_topic_nr = 0;
 static dds_entity_t g_domain = 0;
 static dds_entity_t g_participant   = 0;
 static dds_entity_t g_subscriber    = 0;
@@ -42,15 +40,6 @@ static dds_entity_t g_remote_domain        = 0;
 static dds_entity_t g_remote_participant   = 0;
 static dds_entity_t g_remote_subscriber    = 0;
 
-static char *create_topic_name (const char *prefix, uint32_t nr, char *name, size_t size)
-{
-  /* Get unique g_topic name. */
-  ddsrt_pid_t pid = ddsrt_getpid ();
-  ddsrt_tid_t tid = ddsrt_gettid ();
-  (void) snprintf (name, size, "%s%d_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, pid, tid);
-  return name;
-}
-
 static void whc_init(void)
 {
   /* Domains for pub and sub use a different domain id, but the portgain setting
@@ -177,7 +166,7 @@ static void test_whc_end_state(dds_durability_kind_t d, dds_reliability_kind_t r
   dds_qset_deadline (g_qos, dl ? DEADLINE_DURATION : DDS_INFINITY);
   dds_qset_durability_service (g_qos, 0, dh, dh == KA ? 0 : dhd, DDS_LENGTH_UNLIMITED, DDS_LENGTH_UNLIMITED, DDS_LENGTH_UNLIMITED);
 
-  create_topic_name ("ddsc_whc_end_state_test", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name ("ddsc_whc_end_state_test", name, sizeof name);
   topic = dds_create_topic (g_participant, k ? &Space_Type1_desc : &Space_Type3_desc, name, NULL, NULL);
   CU_ASSERT_FATAL(topic > 0);
   remote_topic = dds_create_topic (g_remote_participant, k ? &Space_Type1_desc : &Space_Type3_desc, name, NULL, NULL);
diff --git a/src/core/ddsc/tests/write_various_types.c b/src/core/ddsc/tests/write_various_types.c
index 861a627..b1f05c3 100644
--- a/src/core/ddsc/tests/write_various_types.c
+++ b/src/core/ddsc/tests/write_various_types.c
@@ -13,19 +13,18 @@
 #include <limits.h>
 
 #include "dds/dds.h"
-#include "CUnit/Theory.h"
-#include "WriteTypes.h"
-
 #include "dds/ddsrt/process.h"
 #include "dds/ddsrt/threads.h"
 #include "dds/ddsrt/environ.h"
 
+#include "test_common.h"
+#include "WriteTypes.h"
+
 #define DDS_DOMAINID_PUB 0
 #define DDS_DOMAINID_SUB 1
 #define DDS_CONFIG_NO_PORT_GAIN "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Discovery><ExternalDomainId>0</ExternalDomainId></Discovery>"
 #define DDS_CONFIG_NO_PORT_GAIN_LOG "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Tracing><OutputFile>cyclonedds_writetypes_various.${CYCLONEDDS_DOMAIN_ID}.${CYCLONEDDS_PID}.log</OutputFile><Verbosity>finest</Verbosity></Tracing><Discovery><ExternalDomainId>0</ExternalDomainId></Discovery>"
 
-static uint32_t g_topic_nr = 0;
 static dds_entity_t g_pub_domain = 0;
 static dds_entity_t g_pub_participant = 0;
 static dds_entity_t g_pub_publisher = 0;
@@ -34,15 +33,6 @@ static dds_entity_t g_sub_domain = 0;
 static dds_entity_t g_sub_participant = 0;
 static dds_entity_t g_sub_subscriber = 0;
 
-static char *create_topic_name (const char *prefix, uint32_t nr, char *name, size_t size)
-{
-  /* Get unique g_topic name. */
-  ddsrt_pid_t pid = ddsrt_getpid ();
-  ddsrt_tid_t tid = ddsrt_gettid ();
-  (void) snprintf (name, size, "%s%d_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, pid, tid);
-  return name;
-}
-
 static void writetypes_init(void)
 {
   /* Domains for pub and sub use a different domain id, but the portgain setting
@@ -152,7 +142,7 @@ CU_Theory((const dds_topic_descriptor_t *desc, compare_fn_t cmp, size_t nsamples
   CU_ASSERT_FATAL (qos != NULL);
   dds_qset_reliability (qos, DDS_RELIABILITY_RELIABLE, DDS_SECS (1));
   dds_qset_writer_data_lifecycle (qos, false);
-  create_topic_name ("ddsc_writetypes_various", g_topic_nr++, name, sizeof name);
+  create_unique_topic_name ("ddsc_writetypes_various", name, sizeof name);
   pub_topic = dds_create_topic (g_pub_participant, desc, name, qos, NULL);
   CU_ASSERT_FATAL (pub_topic > 0);
   sub_topic = dds_create_topic (g_sub_participant, desc, name, qos, NULL);
diff --git a/src/core/ddsi/src/ddsi_eth.c b/src/core/ddsi/src/ddsi_eth.c
index 670667d..a36d314 100644
--- a/src/core/ddsi/src/ddsi_eth.c
+++ b/src/core/ddsi/src/ddsi_eth.c
@@ -16,6 +16,7 @@ int ddsi_eth_enumerate_interfaces (ddsi_tran_factory_t fact, enum transport_sele
     int afs[] = { AF_INET, DDSRT_AF_TERM };
 
     (void)fact;
+    (void)transport_selector;
 
 #if DDSRT_HAVE_IPV6
     if (transport_selector == TRANS_TCP6 ||
diff --git a/src/core/ddsi/src/ddsi_tcp.c b/src/core/ddsi/src/ddsi_tcp.c
index de7a7e6..e6544e2 100644
--- a/src/core/ddsi/src/ddsi_tcp.c
+++ b/src/core/ddsi/src/ddsi_tcp.c
@@ -42,7 +42,9 @@
 union addr {
   struct sockaddr a;
   struct sockaddr_in a4;
+#if DDSRT_HAVE_IPV6
   struct sockaddr_in6 a6;
+#endif
 };
 
 typedef struct ddsi_tcp_conn {
diff --git a/src/core/ddsi/src/ddsi_udp.c b/src/core/ddsi/src/ddsi_udp.c
index 3410510..65d10fd 100644
--- a/src/core/ddsi/src/ddsi_udp.c
+++ b/src/core/ddsi/src/ddsi_udp.c
@@ -30,7 +30,9 @@ union addr {
   struct sockaddr_storage x;
   struct sockaddr a;
   struct sockaddr_in a4;
+#if DDSRT_HAVE_IPV6
   struct sockaddr_in6 a6;
+#endif
 };
 
 typedef struct ddsi_udp_conn {
@@ -559,7 +561,7 @@ static int joinleave_asm_mcgroup (ddsrt_socket_t socket, int join, const nn_loca
   {
     struct ipv6_mreq ipv6mreq;
     memset (&ipv6mreq, 0, sizeof (ipv6mreq));
-    memcpy (&ipv6mreq.ipv6mr_multiaddr, &mcip.a6, sizeof (ipv6mreq.ipv6mr_multiaddr));
+    ipv6mreq.ipv6mr_multiaddr = mcip.a6.sin6_addr;
     ipv6mreq.ipv6mr_interface = interf ? interf->if_index : 0;
     rc = ddsrt_setsockopt (socket, IPPROTO_IPV6, join ? IPV6_JOIN_GROUP : IPV6_LEAVE_GROUP, &ipv6mreq, sizeof (ipv6mreq));
   }
@@ -590,8 +592,8 @@ static int joinleave_ssm_mcgroup (ddsrt_socket_t socket, int join, const nn_loca
     struct group_source_req gsr;
     memset (&gsr, 0, sizeof (gsr));
     gsr.gsr_interface = interf ? interf->if_index : 0;
-    memcpy (&gsr.gsr_group, &mcip.a6, sizeof (gsr.gsr_group));
-    memcpy (&gsr.gsr_source, &srcip.a6, sizeof (gsr.gsr_source));
+    gsr.gsr_group = mcip.x;
+    gsr.gsr_source = srcip.x;
     rc = ddsrt_setsockopt (socket, IPPROTO_IPV6, join ? MCAST_JOIN_SOURCE_GROUP : MCAST_LEAVE_SOURCE_GROUP, &gsr, sizeof (gsr));
   }
   else
diff --git a/src/core/ddsi/src/q_entity.c b/src/core/ddsi/src/q_entity.c
index 5f76314..7c1ff62 100644
--- a/src/core/ddsi/src/q_entity.c
+++ b/src/core/ddsi/src/q_entity.c
@@ -3994,8 +3994,23 @@ dds_return_t writer_wait_for_acks (struct writer *wr, dds_time_t abstimeout)
 
 dds_return_t delete_writer_nolinger_locked (struct writer *wr)
 {
-  ELOGDISC (wr, "delete_writer_nolinger(guid "PGUIDFMT") ...\n", PGUID (wr->e.guid));
   ASSERT_MUTEX_HELD (&wr->e.lock);
+
+  /* We can get here via multiple paths in parallel, in particular: because all data got
+     ACK'd while lingering, and because the linger timeout elapses.  Those two race each
+     other, the first calling this function directly, the second calling from
+     handle_xevk_delete_writer via delete_writer_nolinger.
+
+     There are two practical options to decide whether to ignore the call: one is to check
+     whether the writer is still in the GUID hashes, the second to check whether the state
+     is WRST_DELETING.  The latter seems a bit less surprising. */
+  if (wr->state == WRST_DELETING)
+  {
+    ELOGDISC (wr, "delete_writer_nolinger(guid "PGUIDFMT") already done\n", PGUID (wr->e.guid));
+    return 0;
+  }
+
+  ELOGDISC (wr, "delete_writer_nolinger(guid "PGUIDFMT") ...\n", PGUID (wr->e.guid));
   builtintopic_write (wr->e.gv->builtin_topic_interface, &wr->e, ddsrt_time_wallclock(), false);
   local_reader_ary_setinvalid (&wr->rdary);
   entidx_remove_writer_guid (wr->e.gv->entity_index, wr);
diff --git a/src/core/ddsi/src/q_xevent.c b/src/core/ddsi/src/q_xevent.c
index 3c4ff83..b535bbd 100644
--- a/src/core/ddsi/src/q_xevent.c
+++ b/src/core/ddsi/src/q_xevent.c
@@ -1271,7 +1271,7 @@ static void handle_xevk_pmd_update (struct thread_state1 * const ts1, struct nn_
 
 static void handle_xevk_delete_writer (UNUSED_ARG (struct nn_xpack *xp), struct xevent *ev, UNUSED_ARG (ddsrt_mtime_t tnow))
 {
-  /* don't worry if the writer is already gone by the time we get here. */
+  /* don't worry if the writer is already gone by the time we get here, delete_writer_nolinger checks for that. */
   struct ddsi_domaingv * const gv = ev->evq->gv;
   GVTRACE ("handle_xevk_delete_writer: "PGUIDFMT"\n", PGUID (ev->u.delete_writer.guid));
   delete_writer_nolinger (gv, &ev->u.delete_writer.guid);
diff --git a/src/tools/ddsperf/netload.c b/src/tools/ddsperf/netload.c
index ae716a5..f186e44 100644
--- a/src/tools/ddsperf/netload.c
+++ b/src/tools/ddsperf/netload.c
@@ -78,7 +78,7 @@ struct record_netload_state *record_netload_new (const char *dev, double bw)
   st->bw = bw;
   st->data_valid = false;
   st->errored = false;
-  record_netload (st, NULL, dds_time ());
+  record_netload (st, "", dds_time ());
   return st;
 }