diff --git a/src/core/ddsc/src/dds_domain.c b/src/core/ddsc/src/dds_domain.c
index 9bfb67c..1300b75 100644
--- a/src/core/ddsc/src/dds_domain.c
+++ b/src/core/ddsc/src/dds_domain.c
@@ -169,7 +169,6 @@ static dds_return_t dds_domain_init (dds_domain *domain, dds_domainid_t domain_i
   dds_entity_init_complete (&domain->m_entity);
   return DDS_RETCODE_OK;
 
-  rtps_stop (&domain->gv);
 fail_rtps_start:
   if (domain->gv.config.liveliness_monitoring && dds_global.threadmon_count == 1)
     ddsi_threadmon_stop (dds_global.threadmon);
diff --git a/src/core/ddsc/src/dds_entity.c b/src/core/ddsc/src/dds_entity.c
index 3fcc523..56a5ce4 100644
--- a/src/core/ddsc/src/dds_entity.c
+++ b/src/core/ddsc/src/dds_entity.c
@@ -403,14 +403,17 @@ dds_return_t dds_delete_impl_pinned (dds_entity *e, enum delete_impl_state delst
     ddsrt_mutex_unlock (&p->m_mutex);
   }
 
-  /* Do some specific deletion when needed.  Bootstrapping and its inverse are always a
-     tricky business, and here it is no different: deleting the pseudo-top-level object
-     tears down all kinds of stuff that is supposed to remain in existence (like the
-     entire platform abstraction) and so it must be the final call.  Thus, we rely on it
-     to call "dds_entity_final_deinit_before_free" and return a special error code. */
+  /* Do some specific deletion when needed */
   ret = dds_entity_deriver_delete (e);
   if (ret == DDS_RETCODE_NO_DATA)
+  {
+    /* Bootstrapping and its inverse are always a tricky business, and here it is no different:
+       deleting the pseudo-top-level object tears down all kinds of stuff that is supposed to
+       remain in existence (like the entire platform abstraction) and so it must be the final
+       call.  Thus, we rely on it to call "dds_entity_final_deinit_before_free" and return a
+       special error code that we don't pass on to the caller. */
     ret = DDS_RETCODE_OK;
+  }
   else if (ret != DDS_RETCODE_OK)
   {
     if (parent_to_delete)
@@ -423,6 +426,8 @@ dds_return_t dds_delete_impl_pinned (dds_entity *e, enum delete_impl_state delst
     dds_free (e);
   }
 
+  assert (ret == DDS_RETCODE_OK);
+  (void) ret;
   return (parent_to_delete != NULL) ? dds_delete_impl_pinned (parent_to_delete, DIS_IMPLICIT) : DDS_RETCODE_OK;
 }
 
diff --git a/src/core/ddsc/src/dds_stream.c b/src/core/ddsc/src/dds_stream.c
index 982a532..3f12777 100644
--- a/src/core/ddsc/src/dds_stream.c
+++ b/src/core/ddsc/src/dds_stream.c
@@ -1696,7 +1696,7 @@ static bool prtf_simple_array (char * __restrict *buf, size_t * __restrict bufsi
         else
         {
           if (i != 0)
-            cont = prtf (buf, bufsize, ",");
+            (void) prtf (buf, bufsize, ",");
           cont = prtf_simple (buf, bufsize, is, type);
           i++;
         }
@@ -1708,7 +1708,7 @@ static bool prtf_simple_array (char * __restrict *buf, size_t * __restrict bufsi
       for (size_t i = 0; cont && i < num; i++)
       {
         if (i != 0)
-          cont = prtf (buf, bufsize, ",");
+          (void) prtf (buf, bufsize, ",");
         cont = prtf_simple (buf, bufsize, is, type);
       }
       break;
diff --git a/src/core/ddsc/tests/entity_hierarchy.c b/src/core/ddsc/tests/entity_hierarchy.c
index d52b34f..7983011 100644
--- a/src/core/ddsc/tests/entity_hierarchy.c
+++ b/src/core/ddsc/tests/entity_hierarchy.c
@@ -366,6 +366,7 @@ CU_Test(ddsc_entity_get_children, null, .init=hierarchy_init, .fini=hierarchy_fi
 /*************************************************************************************************/
 
 /*************************************************************************************************/
+#if SIZE_MAX > INT32_MAX
 CU_Test(ddsc_entity_get_children, invalid_size, .init=hierarchy_init, .fini=hierarchy_fini)
 {
     dds_return_t ret;
@@ -373,6 +374,7 @@ CU_Test(ddsc_entity_get_children, invalid_size, .init=hierarchy_init, .fini=hier
     ret = dds_get_children(g_participant, &child, SIZE_MAX);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_BAD_PARAMETER);
 }
+#endif
 /*************************************************************************************************/
 
 /*************************************************************************************************/
diff --git a/src/core/ddsc/tests/instance_get_key.c b/src/core/ddsc/tests/instance_get_key.c
index a0861b3..f8c4cf5 100644
--- a/src/core/ddsc/tests/instance_get_key.c
+++ b/src/core/ddsc/tests/instance_get_key.c
@@ -132,6 +132,7 @@ CU_Test(ddsc_instance_get_key, registered_instance, .init=setup, .fini=teardown)
     ret = dds_instance_get_key(writer, handle, &key_data);
 
     CU_ASSERT_PTR_NOT_NULL_FATAL(key_data.ip);
+    assert (key_data.ip != NULL); /* for the benefit of clang's static analyzer */
     CU_ASSERT_STRING_EQUAL_FATAL(key_data.ip, data.ip);
     CU_ASSERT_EQUAL_FATAL(key_data.port, data.port);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
@@ -162,6 +163,7 @@ CU_Test(ddsc_instance_get_key, readcondition, .init=setup, .fini=teardown)
     ret = dds_instance_get_key(readcondition, handle, &key_data);
 
     CU_ASSERT_PTR_NOT_NULL_FATAL(key_data.ip);
+    assert (key_data.ip != NULL); /* for the benefit of clang's static analyzer */
     CU_ASSERT_STRING_EQUAL_FATAL(key_data.ip, data.ip);
     CU_ASSERT_EQUAL_FATAL(key_data.port, data.port);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
@@ -192,6 +194,7 @@ CU_Test(ddsc_instance_get_key, querycondition, .init=setup, .fini=teardown)
     ret = dds_instance_get_key(querycondition, handle, &key_data);
 
     CU_ASSERT_PTR_NOT_NULL_FATAL(key_data.ip);
+    assert (key_data.ip != NULL); /* for the benefit of clang's static analyzer */
     CU_ASSERT_STRING_EQUAL_FATAL(key_data.ip, data.ip);
     CU_ASSERT_EQUAL_FATAL(key_data.port, data.port);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
diff --git a/src/core/ddsc/tests/listener.c b/src/core/ddsc/tests/listener.c
index b0b42a7..2b5aa00 100644
--- a/src/core/ddsc/tests/listener.c
+++ b/src/core/ddsc/tests/listener.c
@@ -727,7 +727,9 @@ CU_Test(ddsc_listener, publication_matched, .init=init_triggering_test, .fini=fi
     CU_ASSERT_EQUAL_FATAL(publication_matched.last_subscription_handle, reader_hdl);
 
     /* Reset the trigger flags. */
+    ddsrt_mutex_lock(&g_mutex);
     cb_called = 0;
+    ddsrt_mutex_unlock(&g_mutex);
 
     /* Un-match the publication by deleting the reader. */
     dds_delete(g_reader);
@@ -789,7 +791,9 @@ CU_Test(ddsc_listener, subscription_matched, .init=init_triggering_test, .fini=f
     CU_ASSERT_EQUAL_FATAL(subscription_matched.last_publication_handle, writer_hdl);
 
     /* Reset the trigger flags. */
+    ddsrt_mutex_lock(&g_mutex);
     cb_called = 0;
+    ddsrt_mutex_unlock(&g_mutex);
 
     /* Un-match the subscription by deleting the writer. */
     dds_delete(g_writer);
@@ -903,8 +907,10 @@ CU_Test(ddsc_listener, data_available, .init=init_triggering_test, .fini=fini_tr
 
     /* Deleting the writer causes unregisters (or dispose+unregister), and those
        should trigger DATA_AVAILABLE as well */
+    ddsrt_mutex_lock(&g_mutex);
     cb_called = 0;
     cb_reader = 0;
+    ddsrt_mutex_unlock(&g_mutex);
     ret = dds_delete (g_writer);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
     g_writer = 0;
@@ -942,8 +948,10 @@ CU_Test(ddsc_listener, data_available_delete_writer, .init=init_triggering_test,
     CU_ASSERT_EQUAL_FATAL(cb_reader, g_reader);
 
     /* Deleting the writer must trigger DATA_AVAILABLE as well */
+    ddsrt_mutex_lock(&g_mutex);
     cb_called = 0;
     cb_reader = 0;
+    ddsrt_mutex_unlock(&g_mutex);
     ret = dds_delete (g_writer);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
     g_writer = 0;
@@ -991,8 +999,10 @@ CU_Test(ddsc_listener, data_available_delete_writer_disposed, .init=init_trigger
     } while (ret > 0);
 
     /* Deleting the writer should not trigger DATA_AVAILABLE with all instances empty & disposed */
+    ddsrt_mutex_lock(&g_mutex);
     cb_called = 0;
     cb_reader = 0;
+    ddsrt_mutex_unlock(&g_mutex);
     ret = dds_delete (g_writer);
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
     g_writer = 0;
@@ -1174,7 +1184,9 @@ CU_Test(ddsc_listener, liveliness_changed, .init=init_triggering_test, .fini=fin
     CU_ASSERT_EQUAL_FATAL(liveliness_changed.last_publication_handle, writer_hdl);
 
     /* Reset the trigger flags. */
+    ddsrt_mutex_lock(&g_mutex);
     cb_called = 0;
+    ddsrt_mutex_unlock(&g_mutex);
 
     /* Change liveliness again by deleting the writer. */
     dds_delete(g_writer);
diff --git a/src/core/ddsc/tests/participant.c b/src/core/ddsc/tests/participant.c
index 23d5d42..6100f5d 100644
--- a/src/core/ddsc/tests/participant.c
+++ b/src/core/ddsc/tests/participant.c
@@ -47,7 +47,8 @@ CU_Test(ddsc_participant, create_with_no_conf_no_env)
   dds_domainid_t domain_id;
   dds_domainid_t valid_domain=3;
 
-  ddsrt_unsetenv(DDS_PROJECT_NAME_NOSPACE_CAPS"_URI");
+  status = ddsrt_unsetenv(DDS_PROJECT_NAME_NOSPACE_CAPS"_URI");
+  CU_ASSERT_EQUAL_FATAL(status, DDS_RETCODE_OK);
 
   //valid specific domain value
   participant2 = dds_create_participant (valid_domain, NULL, NULL);
diff --git a/src/core/ddsi/include/dds/ddsi/q_entity.h b/src/core/ddsi/include/dds/ddsi/q_entity.h
index c73876b..09069c9 100644
--- a/src/core/ddsi/include/dds/ddsi/q_entity.h
+++ b/src/core/ddsi/include/dds/ddsi/q_entity.h
@@ -91,7 +91,7 @@ struct wr_prd_match {
   seqno_t min_seq; /* smallest ack'd seq nr in subtree */
   seqno_t max_seq; /* sort-of highest ack'd seq nr in subtree (see augment function) */
   seqno_t seq; /* highest acknowledged seq nr */
-  int num_reliable_readers_where_seq_equals_max;
+  int32_t num_reliable_readers_where_seq_equals_max;
   ddsi_guid_t arbitrary_unacked_reader;
   nn_count_t next_acknack; /* next acceptable acknack sequence number */
   nn_count_t next_nackfrag; /* next acceptable nackfrag sequence number */
@@ -260,7 +260,7 @@ struct writer
   uint32_t whc_low, whc_high; /* watermarks for WHC in bytes (counting only unack'd data) */
   nn_etime_t t_rexmit_end; /* time of last 1->0 transition of "retransmitting" */
   nn_etime_t t_whc_high_upd; /* time "whc_high" was last updated for controlled ramp-up of throughput */
-  int num_reliable_readers; /* number of matching reliable PROXY readers */
+  int32_t num_reliable_readers; /* number of matching reliable PROXY readers */
   ddsrt_avl_tree_t readers; /* all matching PROXY readers, see struct wr_prd_match */
   ddsrt_avl_tree_t local_readers; /* all matching LOCAL readers, see struct wr_rd_match */
 #ifdef DDSI_INCLUDE_NETWORK_PARTITIONS
@@ -356,8 +356,8 @@ struct proxy_writer {
   struct entity_common e;
   struct proxy_endpoint_common c;
   ddsrt_avl_tree_t readers; /* matching LOCAL readers, see pwr_rd_match */
-  int n_reliable_readers; /* number of those that are reliable */
-  int n_readers_out_of_sync; /* number of those that require special handling (accepting historical data, waiting for historical data set to become complete) */
+  int32_t n_reliable_readers; /* number of those that are reliable */
+  int32_t n_readers_out_of_sync; /* number of those that require special handling (accepting historical data, waiting for historical data set to become complete) */
   seqno_t last_seq; /* highest known seq published by the writer, not last delivered */
   uint32_t last_fragnum; /* last known frag for last_seq, or ~0u if last_seq not partial */
   nn_count_t nackfragcount; /* last nackfrag seq number */
diff --git a/src/core/ddsi/src/ddsi_raweth.c b/src/core/ddsi/src/ddsi_raweth.c
index cc09ad1..bdb9e27 100644
--- a/src/core/ddsi/src/ddsi_raweth.c
+++ b/src/core/ddsi/src/ddsi_raweth.c
@@ -211,7 +211,12 @@ static ddsi_tran_conn_t ddsi_raweth_create_conn (ddsi_tran_factory_t fact, uint3
     return NULL;
   }
 
-  uc = (ddsi_raweth_conn_t) ddsrt_malloc (sizeof (*uc));
+  if ((uc = (ddsi_raweth_conn_t) ddsrt_malloc (sizeof (*uc))) == NULL)
+  {
+    ddsrt_close(sock);
+    return NULL;
+  }
+
   memset (uc, 0, sizeof (*uc));
   uc->m_sock = sock;
   uc->m_ifindex = addr.sll_ifindex;
@@ -226,7 +231,7 @@ static ddsi_tran_conn_t ddsi_raweth_create_conn (ddsi_tran_factory_t fact, uint3
   uc->m_base.m_disable_multiplexing_fn = 0;
 
   DDS_CTRACE (&fact->gv->logconfig, "ddsi_raweth_create_conn %s socket %d port %u\n", mcast ? "multicast" : "unicast", uc->m_sock, uc->m_base.m_base.m_port);
-  return uc ? &uc->m_base : NULL;
+  return &uc->m_base;
 }
 
 static int isbroadcast(const nn_locator_t *loc)
diff --git a/src/core/ddsi/src/ddsi_tcp.c b/src/core/ddsi/src/ddsi_tcp.c
index 9c7fb41..778d733 100644
--- a/src/core/ddsi/src/ddsi_tcp.c
+++ b/src/core/ddsi/src/ddsi_tcp.c
@@ -554,8 +554,9 @@ static ssize_t ddsi_tcp_conn_write (ddsi_tran_conn_t base, const nn_locator_t *d
 
   /* If not connected attempt to conect */
 
-  if ((conn->m_sock == DDSRT_INVALID_SOCKET) && ! conn->m_base.m_server)
+  if (conn->m_sock == DDSRT_INVALID_SOCKET)
   {
+    assert (!conn->m_base.m_server);
     ddsi_tcp_conn_connect (conn, &msg);
     if (conn->m_sock == DDSRT_INVALID_SOCKET)
     {
diff --git a/src/core/ddsi/src/ddsi_threadmon.c b/src/core/ddsi/src/ddsi_threadmon.c
index 346b0b9..53139e9 100644
--- a/src/core/ddsi/src/ddsi_threadmon.c
+++ b/src/core/ddsi/src/ddsi_threadmon.c
@@ -265,7 +265,7 @@ void ddsi_threadmon_unregister_domain (struct ddsi_threadmon *sl, const struct q
     dummy.gv = gv;
     struct threadmon_domain *tmdom = ddsrt_hh_lookup (sl->domains, &dummy);
     assert (tmdom);
-    ddsrt_hh_remove (sl->domains, tmdom);
+    (void) ddsrt_hh_remove (sl->domains, tmdom);
     ddsrt_mutex_unlock (&sl->lock);
     ddsrt_free (tmdom);
   }
diff --git a/src/core/ddsi/src/q_config.c b/src/core/ddsi/src/q_config.c
index 9ea3ef0..8a0982b 100644
--- a/src/core/ddsi/src/q_config.c
+++ b/src/core/ddsi/src/q_config.c
@@ -1012,6 +1012,8 @@ static size_t cfg_note_vsnprintf (struct cfg_note_buf *bb, const char *fmt, va_l
   return 0;
 }
 
+static void cfg_note_snprintf (struct cfg_note_buf *bb, const char *fmt, ...) ddsrt_attribute_format ((printf, 2, 3));
+
 static void cfg_note_snprintf (struct cfg_note_buf *bb, const char *fmt, ...)
 {
   /* The reason the 2nd call to os_vsnprintf is here and not inside
@@ -1123,6 +1125,8 @@ static size_t cfg_note (struct cfgst *cfgst, uint32_t cat, size_t bsz, const cha
   return 0;
 }
 
+static void cfg_warning (struct cfgst *cfgst, const char *fmt, ...) ddsrt_attribute_format ((printf, 2, 3));
+
 static void cfg_warning (struct cfgst *cfgst, const char *fmt, ...)
 {
   va_list ap;
@@ -1134,6 +1138,8 @@ static void cfg_warning (struct cfgst *cfgst, const char *fmt, ...)
   } while (bsz > 0);
 }
 
+static enum update_result cfg_error (struct cfgst *cfgst, const char *fmt, ...) ddsrt_attribute_format ((printf, 2, 3));
+
 static enum update_result cfg_error (struct cfgst *cfgst, const char *fmt, ...)
 {
   va_list ap;
@@ -1146,6 +1152,8 @@ static enum update_result cfg_error (struct cfgst *cfgst, const char *fmt, ...)
   return URES_ERROR;
 }
 
+static void cfg_logelem (struct cfgst *cfgst, uint32_t sources, const char *fmt, ...) ddsrt_attribute_format ((printf, 3, 4));
+
 static void cfg_logelem (struct cfgst *cfgst, uint32_t sources, const char *fmt, ...)
 {
   /* 89 = 1 + 2 + 31 + 1 + 10 + 2*22: the number of characters in
@@ -1444,7 +1452,7 @@ static void pf_int64_unit (struct cfgst *cfgst, int64_t value, uint32_t sources,
     }
     assert (m > 0);
     assert (unit != NULL);
-    cfg_logelem (cfgst, sources, "%lld %s", value / m, unit);
+    cfg_logelem (cfgst, sources, "%"PRId64" %s", value / m, unit);
   }
 }
 
diff --git a/src/core/ddsi/src/q_ddsi_discovery.c b/src/core/ddsi/src/q_ddsi_discovery.c
index 410c4b0..74d025a 100644
--- a/src/core/ddsi/src/q_ddsi_discovery.c
+++ b/src/core/ddsi/src/q_ddsi_discovery.c
@@ -21,6 +21,7 @@
 #include "dds/ddsrt/md5.h"
 #include "dds/ddsrt/sync.h"
 #include "dds/ddsrt/avl.h"
+#include "dds/ddsrt/string.h"
 #include "dds/ddsi/q_protocol.h"
 #include "dds/ddsi/q_rtps.h"
 #include "dds/ddsi/q_misc.h"
@@ -302,8 +303,8 @@ int spdp_write (struct participant *pp)
       ps.prismtech_participant_version_info.flags |= NN_PRISMTECH_FL_PARTICIPANT_IS_DDSI2;
     ddsrt_mutex_unlock (&pp->e.gv->privileged_pp_lock);
 
-    ddsrt_gethostname(node, sizeof(node)-1);
-    node[sizeof(node)-1] = '\0';
+    if (ddsrt_gethostname(node, sizeof(node)-1) < 0)
+      ddsrt_strlcpy (node, "unknown", sizeof (node));
     size = strlen(node) + strlen(DDS_VERSION) + strlen(DDS_HOST_NAME) + strlen(DDS_TARGET_NAME) + 4; /* + ///'\0' */
     ps.prismtech_participant_version_info.internals = ddsrt_malloc(size);
     (void) snprintf(ps.prismtech_participant_version_info.internals, size, "%s/%s/%s/%s", node, DDS_VERSION, DDS_HOST_NAME, DDS_TARGET_NAME);
diff --git a/src/core/ddsi/src/q_debmon.c b/src/core/ddsi/src/q_debmon.c
index c11b78c..8e629b6 100644
--- a/src/core/ddsi/src/q_debmon.c
+++ b/src/core/ddsi/src/q_debmon.c
@@ -57,6 +57,8 @@ struct debug_monitor {
   int stop;
 };
 
+static int cpf (ddsi_tran_conn_t conn, const char *fmt, ...) ddsrt_attribute_format ((printf, 2, 3));
+
 static int cpf (ddsi_tran_conn_t conn, const char *fmt, ...)
 {
   nn_locator_t loc;
@@ -110,7 +112,7 @@ static int print_addrset_if_notempty (ddsi_tran_conn_t conn, const char *prefix,
 static int print_any_endpoint_common (ddsi_tran_conn_t conn, const char *label, const struct entity_common *e, const struct dds_qos *xqos)
 {
   int x = 0;
-  x += cpf (conn, "  %s %x:%x:%x:%x ", label, PGUID (e->guid));
+  x += cpf (conn, "  %s "PGUIDFMT" ", label, PGUID (e->guid));
   if (xqos->present & QP_PARTITION)
   {
     if (xqos->partition.n > 1) cpf (conn, "{");
@@ -150,7 +152,7 @@ static int print_participants (struct thread_state1 * const ts1, struct q_global
   while ((p = ephash_enum_participant_next (&e)) != NULL)
   {
     ddsrt_mutex_lock (&p->e.lock);
-    x += cpf (conn, "pp %x:%x:%x:%x %s%s\n", PGUID (p->e.guid), p->e.name, p->is_ddsi2_pp ? " [ddsi2]" : "");
+    x += cpf (conn, "pp "PGUIDFMT" %s%s\n", PGUID (p->e.guid), p->e.name, p->is_ddsi2_pp ? " [ddsi2]" : "");
     ddsrt_mutex_unlock (&p->e.lock);
 
     {
@@ -169,7 +171,7 @@ static int print_participants (struct thread_state1 * const ts1, struct q_global
         x += print_addrset_if_notempty (conn, "    as", r->as, "\n");
 #endif
         for (m = ddsrt_avl_iter_first (&rd_writers_treedef, &r->writers, &writ); m; m = ddsrt_avl_iter_next (&writ))
-          x += cpf (conn, "    pwr %x:%x:%x:%x\n", PGUID (m->pwr_guid));
+          x += cpf (conn, "    pwr "PGUIDFMT"\n", PGUID (m->pwr_guid));
         ddsrt_mutex_unlock (&r->e.lock);
       }
       ephash_enum_reader_fini (&er);
@@ -189,20 +191,20 @@ static int print_participants (struct thread_state1 * const ts1, struct q_global
         ddsrt_mutex_lock (&w->e.lock);
         print_endpoint_common (conn, "wr", &w->e, &w->c, w->xqos);
         whc_get_state(w->whc, &whcst);
-        x += cpf (conn, "    whc [%lld,%lld] unacked %"PRIuSIZE"%s [%u,%u] seq %lld seq_xmit %lld cs_seq %lld\n",
+        x += cpf (conn, "    whc [%"PRId64",%"PRId64"] unacked %"PRIuSIZE"%s [%"PRIu32",%"PRIu32"] seq %"PRId64" seq_xmit %"PRId64" cs_seq %"PRId64"\n",
                   whcst.min_seq, whcst.max_seq, whcst.unacked_bytes,
                   w->throttling ? " THROTTLING" : "",
                   w->whc_low, w->whc_high,
                   w->seq, READ_SEQ_XMIT(w), w->cs_seq);
         if (w->reliable)
         {
-          x += cpf (conn, "    hb %u ackhb %lld hb %lld wr %lld sched %lld #rel %d\n",
-                    w->hbcontrol.hbs_since_last_write, w->hbcontrol.t_of_last_ackhb,
-                    w->hbcontrol.t_of_last_hb, w->hbcontrol.t_of_last_write,
-                    w->hbcontrol.tsched, w->num_reliable_readers);
-          x += cpf (conn, "    #acks %u #nacks %u #rexmit %u #lost %u #throttle %u\n",
+          x += cpf (conn, "    hb %"PRIu32" ackhb %"PRId64" hb %"PRId64" wr %"PRId64" sched %"PRId64" #rel %"PRId32"\n",
+                    w->hbcontrol.hbs_since_last_write, w->hbcontrol.t_of_last_ackhb.v,
+                    w->hbcontrol.t_of_last_hb.v, w->hbcontrol.t_of_last_write.v,
+                    w->hbcontrol.tsched.v, w->num_reliable_readers);
+          x += cpf (conn, "    #acks %"PRIu32" #nacks %"PRIu32" #rexmit %"PRIu32" #lost %"PRIu32" #throttle %"PRIu32"\n",
                     w->num_acks_received, w->num_nacks_received, w->rexmit_count, w->rexmit_lost_count, w->throttle_count);
-          x += cpf (conn, "    max-drop-seq %lld\n", writer_max_drop_seq (w));
+          x += cpf (conn, "    max-drop-seq %"PRId64"\n", writer_max_drop_seq (w));
         }
         x += print_addrset_if_notempty (conn, "    as", w->as, "\n");
         for (m = ddsrt_avl_iter_first (&wr_readers_treedef, &w->readers, &rdit); m; m = ddsrt_avl_iter_next (&rdit))
@@ -212,7 +214,7 @@ static int print_participants (struct thread_state1 * const ts1, struct q_global
           wr_prd_flags[1] = m->assumed_in_sync ? 's' : '.';
           wr_prd_flags[2] = m->has_replied_to_hb ? 'a' : '.'; /* a = ack seen */
           wr_prd_flags[3] = 0;
-          x += cpf (conn, "    prd %x:%x:%x:%x %s @ %lld [%lld,%lld] #nacks %u\n",
+          x += cpf (conn, "    prd "PGUIDFMT" %s @ %"PRId64" [%"PRId64",%"PRId64"] #nacks %"PRIu32"\n",
                     PGUID (m->prd_guid), wr_prd_flags, m->seq, m->min_seq, m->max_seq, m->rexmit_requests);
         }
         ddsrt_mutex_unlock (&w->e.lock);
@@ -235,7 +237,7 @@ static int print_proxy_participants (struct thread_state1 * const ts1, struct q_
   while ((p = ephash_enum_proxy_participant_next (&e)) != NULL)
   {
     ddsrt_mutex_lock (&p->e.lock);
-    x += cpf (conn, "proxypp %x:%x:%x:%x%s\n", PGUID (p->e.guid), p->is_ddsi2_pp ? " [ddsi2]" : "");
+    x += cpf (conn, "proxypp "PGUIDFMT"%s\n", PGUID (p->e.guid), p->is_ddsi2_pp ? " [ddsi2]" : "");
     ddsrt_mutex_unlock (&p->e.lock);
     x += print_addrset (conn, "  as data", p->as_default, "");
     x += print_addrset (conn, " meta", p->as_default, "\n");
@@ -253,7 +255,7 @@ static int print_proxy_participants (struct thread_state1 * const ts1, struct q_
         ddsrt_mutex_lock (&r->e.lock);
         print_proxy_endpoint_common (conn, "prd", &r->e, &r->c);
         for (m = ddsrt_avl_iter_first (&rd_writers_treedef, &r->writers, &writ); m; m = ddsrt_avl_iter_next (&writ))
-          x += cpf (conn, "    wr %x:%x:%x:%x\n", PGUID (m->wr_guid));
+          x += cpf (conn, "    wr "PGUIDFMT"\n", PGUID (m->wr_guid));
         ddsrt_mutex_unlock (&r->e.lock);
       }
       ephash_enum_proxy_reader_fini (&er);
@@ -271,20 +273,20 @@ static int print_proxy_participants (struct thread_state1 * const ts1, struct q_
           continue;
         ddsrt_mutex_lock (&w->e.lock);
         print_proxy_endpoint_common (conn, "pwr", &w->e, &w->c);
-        x += cpf (conn, "    last_seq %lld last_fragnum %u\n", w->last_seq, w->last_fragnum);
+        x += cpf (conn, "    last_seq %"PRId64" last_fragnum %"PRIu32"\n", w->last_seq, w->last_fragnum);
         for (m = ddsrt_avl_iter_first (&wr_readers_treedef, &w->readers, &rdit); m; m = ddsrt_avl_iter_next (&rdit))
         {
-          x += cpf (conn, "    rd %x:%x:%x:%x (nack %lld %lld)\n",
-                    PGUID (m->rd_guid), m->seq_last_nack, m->t_last_nack);
+          x += cpf (conn, "    rd "PGUIDFMT" (nack %"PRId64" %"PRId64")\n",
+                    PGUID (m->rd_guid), m->seq_last_nack, m->t_last_nack.v);
           switch (m->in_sync)
           {
             case PRMSS_SYNC:
               break;
             case PRMSS_TLCATCHUP:
-              x += cpf (conn, "      tl-catchup end_of_tl_seq %lld\n", m->u.not_in_sync.end_of_tl_seq);
+              x += cpf (conn, "      tl-catchup end_of_tl_seq %"PRId64"\n", m->u.not_in_sync.end_of_tl_seq);
               break;
             case PRMSS_OUT_OF_SYNC:
-              x += cpf (conn, "      out-of-sync end_of_tl_seq %lld\n", m->u.not_in_sync.end_of_tl_seq);
+              x += cpf (conn, "      out-of-sync end_of_tl_seq %"PRId64"\n", m->u.not_in_sync.end_of_tl_seq);
               break;
           }
         }
diff --git a/src/core/ddsi/src/q_receive.c b/src/core/ddsi/src/q_receive.c
index f877606..f08d9bb 100644
--- a/src/core/ddsi/src/q_receive.c
+++ b/src/core/ddsi/src/q_receive.c
@@ -1071,7 +1071,7 @@ static void handle_Heartbeat_helper (struct pwr_rd_match * const wn, struct hand
     refseq = nn_reorder_next_seq (pwr->reorder) - 1;
   else
     refseq = nn_reorder_next_seq (wn->u.not_in_sync.reorder) - 1;
-    RSTTRACE (" "PGUIDFMT"@%"PRId64"%s", PGUID (wn->rd_guid), refseq, (wn->in_sync == PRMSS_SYNC) ? "(sync)" : (wn->in_sync == PRMSS_TLCATCHUP) ? "(tlcatchup)" : "");
+  RSTTRACE (" "PGUIDFMT"@%"PRId64"%s", PGUID (wn->rd_guid), refseq, (wn->in_sync == PRMSS_SYNC) ? "(sync)" : (wn->in_sync == PRMSS_TLCATCHUP) ? "(tlcatchup)" : "");
 
   /* Reschedule AckNack transmit if deemed appropriate; unreliable
      readers have acknack_xevent == NULL and can't do this.
@@ -2437,7 +2437,7 @@ static int handle_DataFrag (struct receiver_state *rst, nn_etime_t tnow, struct
       payload_offset = submsg_offset + (unsigned) size;
 
     begin = (msg->fragmentStartingNum - 1) * msg->fragmentSize;
-    if (msg->fragmentSize * msg->fragmentsInSubmessage > ((unsigned char *) msg + size - datap)) {
+    if ((uint32_t) msg->fragmentSize * msg->fragmentsInSubmessage > (uint32_t) ((unsigned char *) msg + size - datap)) {
       /* this happens for the last fragment (which usually is short) --
          and is included here merely as a sanity check, because that
          would mean the computed endp1'd be larger than the sample
diff --git a/src/core/ddsi/src/q_sockwaitset.c b/src/core/ddsi/src/q_sockwaitset.c
index e0cecef..dabff22 100644
--- a/src/core/ddsi/src/q_sockwaitset.c
+++ b/src/core/ddsi/src/q_sockwaitset.c
@@ -618,12 +618,23 @@ static void os_sockWaitsetNewSet (os_sockWaitsetSet * set)
   set->n = 1;
 }
 
+static void os_sockWaitsetFreeSet (os_sockWaitsetSet * set)
+{
+  ddsrt_free (set->fds);
+  ddsrt_free (set->conns);
+}
+
 static void os_sockWaitsetNewCtx (os_sockWaitsetCtx ctx)
 {
   os_sockWaitsetNewSet (&ctx->set);
   FD_ZERO (&ctx->rdset);
 }
 
+static void os_sockWaitsetFreeCtx (os_sockWaitsetCtx ctx)
+{
+  os_sockWaitsetFreeSet (&ctx->set);
+}
+
 os_sockWaitset os_sockWaitsetNew (void)
 {
   int result;
@@ -642,40 +653,16 @@ os_sockWaitset os_sockWaitsetNew (void)
   ws->pipe[0] = -1;
   ws->pipe[1] = -1;
   result = 0;
-#elif defined(__VXWORKS__)
-  int make_pipe (int pfd[2])
-  {
-    char pipename[OSPL_PIPENAMESIZE];
-    int pipecount=0;
-    do
-    {
-      snprintf ((char*)&pipename, sizeof(pipename), "/pipe/ospl%d", pipecount++ );
-    }
-    while ((result = pipeDevCreate ((char*) &pipename, 1, 1)) == -1 && os_getErrno() == EINVAL);
-    if (result != -1)
-    {
-      result = open ((char*) &pipename, O_RDWR, 0644);
-      if (result != -1)
-      {
-        ws->pipe[0] = result;
-        result = open ((char*) &pipename, O_RDWR, 0644);
-        if (result != -1)
-        {
-          ws->pipe[1] = result;
-        }
-        else
-        {
-          close (ws->pipe[0]);
-          pipeDevDelete (pipename, 0);
-        }
-      }
-    }
-  }
 #else
   result = make_pipe (ws->pipe);
 #endif
-  assert (result != -1);
-  (void) result;
+  if (result == -1)
+  {
+    os_sockWaitsetFreeCtx (&ws->ctx);
+    os_sockWaitsetFreeSet (&ws->set);
+    ddsrt_free (ws);
+    return NULL;
+  }
 
 #if !defined(LWIP_SOCKET)
   ws->set.fds[0] = ws->pipe[0];
@@ -685,8 +672,8 @@ os_sockWaitset os_sockWaitsetNew (void)
   ws->set.conns[0] = NULL;
 
 #if !defined(__VXWORKS__) && !defined(_WIN32) && !defined(LWIP_SOCKET)
-  fcntl (ws->pipe[0], F_SETFD, fcntl (ws->pipe[0], F_GETFD) | FD_CLOEXEC);
-  fcntl (ws->pipe[1], F_SETFD, fcntl (ws->pipe[1], F_GETFD) | FD_CLOEXEC);
+  (void) fcntl (ws->pipe[0], F_SETFD, fcntl (ws->pipe[0], F_GETFD) | FD_CLOEXEC);
+  (void) fcntl (ws->pipe[1], F_SETFD, fcntl (ws->pipe[1], F_GETFD) | FD_CLOEXEC);
 #endif
 #if !defined(LWIP_SOCKET)
   FD_SET (ws->set.fds[0], &ws->ctx.rdset);
@@ -707,17 +694,6 @@ static void os_sockWaitsetGrow (os_sockWaitsetSet * set)
   set->fds = ddsrt_realloc (set->fds, set->sz * sizeof (*set->fds));
 }
 
-static void os_sockWaitsetFreeSet (os_sockWaitsetSet * set)
-{
-  ddsrt_free (set->fds);
-  ddsrt_free (set->conns);
-}
-
-static void os_sockWaitsetFreeCtx (os_sockWaitsetCtx ctx)
-{
-  os_sockWaitsetFreeSet (&ctx->set);
-}
-
 void os_sockWaitsetFree (os_sockWaitset ws)
 {
 #if defined(__VXWORKS__) && defined(__RTP__)
diff --git a/src/core/ddsi/src/q_transmit.c b/src/core/ddsi/src/q_transmit.c
index 94799ea..1f2a150 100644
--- a/src/core/ddsi/src/q_transmit.c
+++ b/src/core/ddsi/src/q_transmit.c
@@ -163,7 +163,7 @@ struct nn_xmsg *writer_hbcontrol_create_heartbeat (struct writer *wr, const stru
   }
   else
   {
-    const int n_unacked = wr->num_reliable_readers - root_rdmatch (wr)->num_reliable_readers_where_seq_equals_max;
+    const int32_t n_unacked = wr->num_reliable_readers - root_rdmatch (wr)->num_reliable_readers_where_seq_equals_max;
     assert (n_unacked >= 0);
     if (n_unacked == 0)
       prd_guid = NULL;
@@ -182,7 +182,7 @@ struct nn_xmsg *writer_hbcontrol_create_heartbeat (struct writer *wr, const stru
     ETRACE (wr, "multicasting ");
   else
     ETRACE (wr, "unicasting to prd "PGUIDFMT" ", PGUID (*prd_guid));
-  ETRACE (wr, "(rel-prd %d seq-eq-max %d seq %"PRId64" maxseq %"PRId64")\n",
+  ETRACE (wr, "(rel-prd %"PRId32" seq-eq-max %"PRId32" seq %"PRId64" maxseq %"PRId64")\n",
           wr->num_reliable_readers,
           ddsrt_avl_is_empty (&wr->readers) ? -1 : root_rdmatch (wr)->num_reliable_readers_where_seq_equals_max,
           wr->seq,
diff --git a/src/ddsrt/src/retcode.c b/src/ddsrt/src/retcode.c
index 930a327..5cd0590 100644
--- a/src/ddsrt/src/retcode.c
+++ b/src/ddsrt/src/retcode.c
@@ -10,6 +10,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include "dds/ddsrt/retcode.h"
+#include "dds/ddsrt/static_assert.h"
 
 static const char *retcodes[] = {
   "Success",
@@ -45,6 +46,7 @@ const char *dds_strretcode (dds_return_t rc)
 {
   const dds_return_t nretcodes = (dds_return_t) (sizeof (retcodes) / sizeof (retcodes[0]));
   const dds_return_t nxretcodes = (dds_return_t) (sizeof (xretcodes) / sizeof (xretcodes[0]));
+  DDSRT_STATIC_ASSERT (DDS_XRETCODE_BASE < 0);
   /* Retcodes used to be positive, but return values from the API would be a negative
      and so there are/were/may be places outside the core library where dds_strretcode
      is called with a -N for N a API return value, so ... play it safe and use the
@@ -53,8 +55,8 @@ const char *dds_strretcode (dds_return_t rc)
     rc = -rc;
   if (rc >= 0 && rc < nretcodes)
     return retcodes[rc];
-  else if (rc >= DDS_XRETCODE_BASE && rc < DDS_XRETCODE_BASE + nxretcodes)
-    return xretcodes[rc - DDS_XRETCODE_BASE];
+  else if (rc >= (-DDS_XRETCODE_BASE) && rc < (-DDS_XRETCODE_BASE) + nxretcodes)
+    return xretcodes[rc - (-DDS_XRETCODE_BASE)];
   else
     return "Unknown return code";
 }
diff --git a/src/ddsrt/tests/environ.c b/src/ddsrt/tests/environ.c
index 6e22876..0a11334 100644
--- a/src/ddsrt/tests/environ.c
+++ b/src/ddsrt/tests/environ.c
@@ -10,6 +10,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #include <stdlib.h>
+#include <assert.h>
 
 #include "CUnit/Theory.h"
 #include "dds/ddsrt/environ.h"
@@ -49,11 +50,13 @@ CU_Test(ddsrt_environ, setenv)
   CU_ASSERT_EQUAL(rc, DDS_RETCODE_OK);
   ptr = getenv(name);
   CU_ASSERT_PTR_NOT_NULL(ptr);
+  assert (ptr != NULL); /* for the benefit of clang's static analyzer */
   CU_ASSERT_STRING_EQUAL(ptr, "bar");
   /* Ensure value is copied into the environment. */
   value[2] = 'z';
   ptr = getenv(name);
   CU_ASSERT_PTR_NOT_NULL(ptr);
+  assert (ptr != NULL); /* for the benefit of clang's static analyzer */
   CU_ASSERT_STRING_EQUAL(ptr, "bar");
   rc = ddsrt_setenv(name, "");
   CU_ASSERT_EQUAL(rc, DDS_RETCODE_OK);
diff --git a/src/ddsrt/tests/ifaddrs.c b/src/ddsrt/tests/ifaddrs.c
index 6035724..13dda43 100644
--- a/src/ddsrt/tests/ifaddrs.c
+++ b/src/ddsrt/tests/ifaddrs.c
@@ -9,6 +9,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
+#include <assert.h>
 #include "dds/ddsrt/cdtors.h"
 #include "dds/ddsrt/ifaddrs.h"
 #include "dds/ddsrt/retcode.h"
@@ -73,6 +74,7 @@ CU_Test(ddsrt_getifaddrs, ipv4)
   CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
   for (ifa = ifa_root; ifa; ifa = ifa->next) {
     CU_ASSERT_PTR_NOT_EQUAL_FATAL(ifa->addr, NULL);
+    assert (ifa->addr != NULL); /* for the benefit of clang's static analyzer */
     CU_ASSERT_EQUAL(ifa->addr->sa_family, AF_INET);
     if (ifa->addr->sa_family == AF_INET) {
       if (ifa->flags & IFF_LOOPBACK) {
@@ -130,6 +132,7 @@ CU_Test(ddsrt_getifaddrs, ipv6)
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
     for (ifa = ifa_root; ifa; ifa = ifa->next) {
       CU_ASSERT_PTR_NOT_EQUAL_FATAL(ifa->addr, NULL);
+      assert (ifa->addr != NULL); /* for the benefit of clang's static analyzer */
       CU_ASSERT_EQUAL(ifa->addr->sa_family, AF_INET6);
       if (ifa->addr->sa_family == AF_INET6) {
         have_ipv6 = 1;
@@ -170,6 +173,7 @@ CU_Test(ddsrt_getifaddrs, ipv4_n_ipv6)
     CU_ASSERT_EQUAL_FATAL(ret, DDS_RETCODE_OK);
     for (ifa = ifa_root; ifa; ifa = ifa->next) {
       CU_ASSERT_PTR_NOT_EQUAL_FATAL(ifa->addr, NULL);
+      assert (ifa->addr != NULL); /* for the benefit of clang's static analyzer */
       CU_ASSERT(ifa->addr->sa_family == AF_INET ||
                 ifa->addr->sa_family == AF_INET6);
       if (ifa->addr->sa_family == AF_INET) {
diff --git a/src/ddsrt/tests/log.c b/src/ddsrt/tests/log.c
index 63c0438..36e3e1a 100644
--- a/src/ddsrt/tests/log.c
+++ b/src/ddsrt/tests/log.c
@@ -254,11 +254,8 @@ CU_Test(dds_log, no_sink, .init=setup, .fini=teardown)
   ptr = NULL;
   DDS_ERROR("foobaz\n");
   ret = fseek(fh, 0, SEEK_SET);
+  CU_ASSERT_EQUAL_FATAL(ret, 0);
   CU_ASSERT_PTR_NULL(ptr);
-  if (ptr != NULL) {
-    ddsrt_free(ptr);
-    ptr = NULL;
-  }
   buf[0]= '\0';
   cnt[1] = fread(buf, 1, sizeof(buf) - 1, fh);
 #ifdef _WIN32
diff --git a/src/ddsrt/tests/process_app.c b/src/ddsrt/tests/process_app.c
index a0c402a..1613391 100644
--- a/src/ddsrt/tests/process_app.c
+++ b/src/ddsrt/tests/process_app.c
@@ -29,9 +29,13 @@ static int test_sleep(int argi, int argc, char **argv)
   argi++;
   if (argi < argc) {
     long long dorment;
-    ddsrt_strtoll(argv[argi], NULL, 0, &dorment);
-    printf(" Process: sleep %d seconds.\n", (int)dorment);
-    dds_sleepfor(DDS_SECS((int64_t)dorment));
+    if (ddsrt_strtoll(argv[argi], NULL, 0, &dorment) != DDS_RETCODE_OK || dorment < 0 || dorment > INT32_MAX) {
+      printf(" Process: invalid --sleep argument.\n");
+      return TEST_EXIT_WRONG_ARGS;
+    } else {
+      printf(" Process: sleep %d seconds.\n", (int)dorment);
+      dds_sleepfor(DDS_SECS((int64_t)dorment));
+    }
   } else {
     printf(" Process: no --sleep value.\n");
     return TEST_EXIT_WRONG_ARGS;
diff --git a/src/mpt/tests/qos/procs/ppud.c b/src/mpt/tests/qos/procs/ppud.c
index 25ae30a..0ac52f0 100644
--- a/src/mpt/tests/qos/procs/ppud.c
+++ b/src/mpt/tests/qos/procs/ppud.c
@@ -355,7 +355,7 @@ MPT_ProcessEntry (rwud,
           size_t chkusz = 0;
           if (!qget (chk, &chkud, &chkusz))
             MPT_ASSERT (0, "Check QoS: no %s present\n", qname);
-          MPT_ASSERT (chkusz == expusz && (expusz == 0 || memcmp (chkud, expud, expusz) == 0),
+          MPT_ASSERT (chkusz == expusz && (expusz == 0 || (chkud != NULL && memcmp (chkud, expud, expusz) == 0)),
                       "Retrieved %s differs from group data just set (%zu/%s vs %zu/%s)\n", qname,
                       chkusz, chkud ? (char *) chkud : "(null)", expusz, expud ? (char *) expud : "(null)");
           dds_free (chkud);