diff --git a/rcl_lifecycle/include/rcl_lifecycle/rcl_lifecycle.h b/rcl_lifecycle/include/rcl_lifecycle/rcl_lifecycle.h
index a5ce128..22f59fc 100644
--- a/rcl_lifecycle/include/rcl_lifecycle/rcl_lifecycle.h
+++ b/rcl_lifecycle/include/rcl_lifecycle/rcl_lifecycle.h
@@ -30,6 +30,7 @@ rcl_lifecycle_state_machine_t
 rcl_lifecycle_get_zero_initialized_state_machine();
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_ret_t
 rcl_lifecycle_state_machine_init(
   rcl_lifecycle_state_machine_t * state_machine,
@@ -42,17 +43,20 @@ rcl_lifecycle_state_machine_init(
   bool default_states);
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_ret_t
 rcl_lifecycle_state_machine_fini(
   rcl_lifecycle_state_machine_t * state_machine,
   rcl_node_t * node_handle);
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_ret_t
 rcl_lifecycle_state_machine_is_initialized(
   const rcl_lifecycle_state_machine_t * state_machine);
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 const rcl_lifecycle_transition_t *
 rcl_lifecycle_is_valid_callback_transition(
   rcl_lifecycle_state_machine_t * state_machine,
@@ -70,6 +74,7 @@ rcl_lifecycle_is_valid_callback_transition(
  * callbacks such as RCL_LIFECYCLE_RET_OK et. al.
  */
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_ret_t
 rcl_lifecycle_trigger_transition(
   rcl_lifecycle_state_machine_t * state_machine,
diff --git a/rcl_lifecycle/include/rcl_lifecycle/transition_map.h b/rcl_lifecycle/include/rcl_lifecycle/transition_map.h
index c06addd..c6a0cb7 100644
--- a/rcl_lifecycle/include/rcl_lifecycle/transition_map.h
+++ b/rcl_lifecycle/include/rcl_lifecycle/transition_map.h
@@ -16,6 +16,7 @@
 #ifndef RCL_LIFECYCLE__TRANSITION_MAP_H_
 #define RCL_LIFECYCLE__TRANSITION_MAP_H_
 
+#include <rcl/macros.h>
 #include <rcl_lifecycle/data_types.h>
 
 #if __cplusplus
@@ -37,12 +38,14 @@ rcl_lifecycle_register_transition(
   rcl_lifecycle_ret_t key);
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_lifecycle_state_t *
 rcl_lifecycle_get_state(
   rcl_lifecycle_transition_map_t * transition_map,
   unsigned int state_id);
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_lifecycle_transition_t *
 rcl_lifecycle_get_transitions(
   rcl_lifecycle_transition_map_t * transition_map,
diff --git a/rcl_lifecycle/src/com_interface.c b/rcl_lifecycle/src/com_interface.c
index b3a2a61..c5dadca 100644
--- a/rcl_lifecycle/src/com_interface.c
+++ b/rcl_lifecycle/src/com_interface.c
@@ -22,18 +22,16 @@ extern "C"
 #include <stdio.h>
 #include <string.h>
 
-#include "rcutils/concat.h"
+#include <rcl/error_handling.h>
+#include <rcutils/concat.h>
+#include <rmw/validate_full_topic_name.h>
+#include <rosidl_generator_c/message_type_support_struct.h>
+#include <rosidl_generator_c/string_functions.h>
 
-#include "lifecycle_msgs/msg/transition_event.h"
-
-#include "rcl/error_handling.h"
+#include <lifecycle_msgs/msg/transition_event.h>
 
 #include "rcl_lifecycle/data_types.h"
 
-#include "rmw/validate_full_topic_name.h"
-
-#include "rosidl_generator_c/message_type_support_struct.h"
-#include "rosidl_generator_c/string_functions.h"
 
 static lifecycle_msgs__msg__TransitionEvent msg;
 static const char * pub_transition_event_suffix = "transition_event";
diff --git a/rcl_lifecycle/src/com_interface.h b/rcl_lifecycle/src/com_interface.h
index 2b5ec0f..faa8f8f 100644
--- a/rcl_lifecycle/src/com_interface.h
+++ b/rcl_lifecycle/src/com_interface.h
@@ -20,12 +20,15 @@ extern "C"
 {
 #endif
 
+#include <rcl/macros.h>
+
 #include "rcl_lifecycle/data_types.h"
 
 rcl_lifecycle_com_interface_t
 rcl_lifecycle_get_zero_initialized_com_interface();
 
 rcl_ret_t
+RCL_WARN_UNUSED
 rcl_lifecycle_com_interface_init(
   rcl_lifecycle_com_interface_t * com_interface,
   rcl_node_t * node_handle,
@@ -36,11 +39,13 @@ rcl_lifecycle_com_interface_init(
   const rosidl_service_type_support_t * ts_srv_get_available_transitions);
 
 rcl_ret_t
+RCL_WARN_UNUSED
 rcl_lifecycle_com_interface_fini(
   rcl_lifecycle_com_interface_t * com_interface,
   rcl_node_t * node_handle);
 
 rcl_ret_t
+RCL_WARN_UNUSED
 rcl_lifecycle_com_interface_publish_notification(
   rcl_lifecycle_com_interface_t * com_interface,
   const rcl_lifecycle_state_t * start, const rcl_lifecycle_state_t * goal);
diff --git a/rcl_lifecycle/src/default_state_machine.h b/rcl_lifecycle/src/default_state_machine.h
index 1d629ea..a9f9af7 100644
--- a/rcl_lifecycle/src/default_state_machine.h
+++ b/rcl_lifecycle/src/default_state_machine.h
@@ -15,6 +15,7 @@
 #ifndef DEFAULT_STATE_MACHINE_H_
 #define DEFAULT_STATE_MACHINE_H_
 
+#include <rcl/macros.h>
 #include <rcl/types.h>
 
 #include "rcl_lifecycle/data_types.h"
@@ -26,6 +27,7 @@ extern "C"
 #endif
 
 RCL_LIFECYCLE_PUBLIC
+RCL_WARN_UNUSED
 rcl_ret_t
 rcl_lifecycle_init_default_state_machine(rcl_lifecycle_state_machine_t * state_machine);
 
diff --git a/rcl_lifecycle/src/rcl_lifecycle.c b/rcl_lifecycle/src/rcl_lifecycle.c
index b81b993..18bd703 100644
--- a/rcl_lifecycle/src/rcl_lifecycle.c
+++ b/rcl_lifecycle/src/rcl_lifecycle.c
@@ -165,8 +165,12 @@ rcl_lifecycle_trigger_transition(
   }
   state_machine->current_state = transition->goal;
   if (publish_notification) {
-    rcl_lifecycle_com_interface_publish_notification(
+    rcl_ret_t ret = rcl_lifecycle_com_interface_publish_notification(
       &state_machine->com_interface, transition->start, state_machine->current_state);
+    if (ret != RCL_RET_OK) {
+      RCL_SET_ERROR_MSG("Could not publish transition", rcl_get_default_allocator());
+      return RCL_RET_ERROR;
+    }
   }
 
   return RCL_RET_OK;
diff --git a/rcl_lifecycle/test/test_default_state_machine.cpp b/rcl_lifecycle/test/test_default_state_machine.cpp
index 3668def..78334ad 100644
--- a/rcl_lifecycle/test/test_default_state_machine.cpp
+++ b/rcl_lifecycle/test/test_default_state_machine.cpp
@@ -97,8 +97,11 @@ TEST_F(TestDefaultStateMachine, zero_init) {
 }
 
 TEST_F(TestDefaultStateMachine, default_sequence) {
+  rcl_ret_t ret;
+
   rcl_lifecycle_state_machine_t state_machine = rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   test_trigger_transition(
     &state_machine,
@@ -162,8 +165,11 @@ TEST_F(TestDefaultStateMachine, default_sequence) {
 }
 
 TEST_F(TestDefaultStateMachine, wrong_default_sequence) {
+  rcl_ret_t ret;
+
   rcl_lifecycle_state_machine_t state_machine = rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   { // supposed to stay unconfigured for all invalid
     for (auto it = keys.begin(); it != keys.end(); ++it) {
@@ -334,8 +340,11 @@ TEST_F(TestDefaultStateMachine, wrong_default_sequence) {
 }
 
 TEST_F(TestDefaultStateMachine, default_in_a_loop) {
+  rcl_ret_t ret;
+
   rcl_lifecycle_state_machine_t state_machine = rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   for (auto i = 0; i < 5; ++i) {
     test_trigger_transition(
@@ -401,8 +410,11 @@ TEST_F(TestDefaultStateMachine, default_in_a_loop) {
 }
 
 TEST_F(TestDefaultStateMachine, default_sequence_failure) {
+  rcl_ret_t ret;
+
   rcl_lifecycle_state_machine_t state_machine = rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   test_trigger_transition(
     &state_machine,
@@ -511,8 +523,11 @@ TEST_F(TestDefaultStateMachine, default_sequence_failure) {
 }
 
 TEST_F(TestDefaultStateMachine, default_sequence_error_resolved) {
+  rcl_ret_t ret;
+
   rcl_lifecycle_state_machine_t state_machine = rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   test_trigger_transition(
     &state_machine,
@@ -652,10 +667,13 @@ TEST_F(TestDefaultStateMachine, default_sequence_error_resolved) {
 }
 
 TEST_F(TestDefaultStateMachine, default_sequence_error_unresolved) {
+  rcl_ret_t ret;
+
   {
     rcl_lifecycle_state_machine_t state_machine =
       rcl_lifecycle_get_zero_initialized_state_machine();
-    rcl_lifecycle_init_default_state_machine(&state_machine);
+    ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+    EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
     test_trigger_transition(
       &state_machine,
@@ -679,7 +697,8 @@ TEST_F(TestDefaultStateMachine, default_sequence_error_unresolved) {
   {
     rcl_lifecycle_state_machine_t state_machine =
       rcl_lifecycle_get_zero_initialized_state_machine();
-    rcl_lifecycle_init_default_state_machine(&state_machine);
+    ret = rcl_lifecycle_init_default_state_machine(&state_machine);
+    EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
     test_trigger_transition(
       &state_machine,
diff --git a/rcl_lifecycle/test/test_multiple_instances.cpp b/rcl_lifecycle/test/test_multiple_instances.cpp
index 20c26d9..236f98e 100644
--- a/rcl_lifecycle/test/test_multiple_instances.cpp
+++ b/rcl_lifecycle/test/test_multiple_instances.cpp
@@ -73,23 +73,29 @@ test_trigger_transition(
 }
 
 TEST_F(TestMultipleInstances, default_sequence_error_unresolved) {
+  rcl_ret_t ret;
+
   rcl_lifecycle_state_machine_t state_machine1 =
     rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine1);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine1);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   rcl_lifecycle_state_machine_t state_machine2 =
     rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine2);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine2);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   rcl_lifecycle_state_machine_t state_machine3 =
     rcl_lifecycle_get_zero_initialized_state_machine();
-  rcl_lifecycle_init_default_state_machine(&state_machine3);
+  ret = rcl_lifecycle_init_default_state_machine(&state_machine3);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   test_trigger_transition(
     &state_machine1,
     lifecycle_msgs__msg__Transition__TRANSITION_CONFIGURE,
     lifecycle_msgs__msg__State__PRIMARY_STATE_UNCONFIGURED,
     lifecycle_msgs__msg__State__TRANSITION_STATE_CONFIGURING);
+  EXPECT_EQ(RCL_RET_OK, ret) << rcl_get_error_string_safe();
 
   EXPECT_EQ(
     lifecycle_msgs__msg__State__TRANSITION_STATE_CONFIGURING, state_machine1.current_state->id);