use maybe_unused attribute for the portability. (#2758)

Signed-off-by: Tomoya Fujita <[email protected]>

Author: fujitatomoya

rclcpp/include/rclcpp/allocator/allocator_deleter.hpp

@@ -69,18 +69,17 @@ class AllocatorDeleter
 };
 
 template<typename Alloc, typename T, typename D>
-void set_allocator_for_deleter(D * deleter, Alloc * alloc)
+void set_allocator_for_deleter([[maybe_unused]] D * deleter, [[maybe_unused]] Alloc * alloc)
 {
-  (void) alloc;
-  (void) deleter;
   throw std::runtime_error("Reached unexpected template specialization");
 }
 
 template<typename T, typename U>
-void set_allocator_for_deleter(std::default_delete<T> * deleter, std::allocator<U> * alloc)
+void set_allocator_for_deleter(
+  [[maybe_unused]] std::default_delete<T> * deleter,
+  [[maybe_unused]] std::allocator<U> * alloc)
 {
-  (void) deleter;
-  (void) alloc;
+  // This function is intentionally left empty.
 }
 
 template<typename Alloc, typename T>

rclcpp/include/rclcpp/event_handler.hpp

@@ -293,9 +293,8 @@ class EventHandler : public EventHandlerBase
   }
 
   std::shared_ptr<void>
-  take_data_by_entity_id(size_t id) override
+  take_data_by_entity_id([[maybe_unused]] size_t id) override
   {
-    (void)id;
     return take_data();
   }
 

rclcpp/include/rclcpp/experimental/subscription_intra_process_base.hpp

@@ -79,9 +79,8 @@ class SubscriptionIntraProcessBase : public rclcpp::Waitable
   take_data() override = 0;
 
   std::shared_ptr<void>
-  take_data_by_entity_id(size_t id) override
+  take_data_by_entity_id([[maybe_unused]] size_t id) override
   {
-    (void)id;
     return take_data();
   }
 

rclcpp/include/rclcpp/experimental/subscription_intra_process_buffer.hpp

@@ -110,9 +110,8 @@ class SubscriptionIntraProcessBuffer : public SubscriptionROSMsgIntraProcessBuff
   }
 
   bool
-  is_ready(const rcl_wait_set_t & wait_set) override
+  is_ready([[maybe_unused]] const rcl_wait_set_t & wait_set) override
   {
-    (void) wait_set;
     return buffer_->has_data();
   }
 

rclcpp/include/rclcpp/publisher.hpp

@@ -143,12 +143,9 @@ class Publisher : public PublisherBase
   post_init_setup(
     rclcpp::node_interfaces::NodeBaseInterface * node_base,
     const std::string & topic,
-    const rclcpp::QoS & qos,
-    const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options)
+    [[maybe_unused]] const rclcpp::QoS & qos,
+    [[maybe_unused]] const rclcpp::PublisherOptionsWithAllocator<AllocatorT> & options)
   {
-    (void)qos;
-    (void)options;
-
     // If needed, setup intra process communication.
     if (rclcpp::detail::resolve_use_intra_process(options_, *node_base)) {
       auto context = node_base->get_context();

rclcpp/include/rclcpp/strategies/message_pool_memory_strategy.hpp

@@ -114,9 +114,9 @@ class MessagePoolMemoryStrategy
    * all references.
    * \param[in] msg Shared pointer to the message to return.
    */
-  void return_message(std::shared_ptr<MessageT> & msg)
+  void return_message([[maybe_unused]] std::shared_ptr<MessageT> & msg)
   {
-    (void)msg;
+    // This function is intentionally left empty.
   }
 
 protected:

rclcpp/include/rclcpp/subscription.hpp

@@ -209,13 +209,11 @@ class Subscription : public SubscriptionBase
   /// Called after construction to continue setup that requires shared_from_this().
   void
   post_init_setup(
-    rclcpp::node_interfaces::NodeBaseInterface * node_base,
-    const rclcpp::QoS & qos,
-    const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options)
+    [[maybe_unused]] rclcpp::node_interfaces::NodeBaseInterface * node_base,
+    [[maybe_unused]] const rclcpp::QoS & qos,
+    [[maybe_unused]] const rclcpp::SubscriptionOptionsWithAllocator<AllocatorT> & options)
   {
-    (void)node_base;
-    (void)qos;
-    (void)options;
+    // This function is intentionally left empty.
   }
 
   /// Take the next message from the inter-process subscription.
@@ -422,20 +420,17 @@ class Subscription : public SubscriptionBase
 
   void
   return_dynamic_message(
-    rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr & message) override
+    [[maybe_unused]] rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr & message) override
   {
-    (void) message;
     throw rclcpp::exceptions::UnimplementedError(
             "return_dynamic_message is not implemented for Subscription");
   }
 
   void
   handle_dynamic_message(
-    const rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr & message,
-    const rclcpp::MessageInfo & message_info) override
+    [[maybe_unused]] const rclcpp::dynamic_typesupport::DynamicMessage::SharedPtr & message,
+    [[maybe_unused]] const rclcpp::MessageInfo & message_info) override
   {
-    (void) message;
-    (void) message_info;
     throw rclcpp::exceptions::UnimplementedError(
             "handle_dynamic_message is not implemented for Subscription");
   }

rclcpp/src/rclcpp/detail/rmw_implementation_specific_publisher_payload.cpp

@@ -23,10 +23,9 @@ namespace detail
 
 void
 RMWImplementationSpecificPublisherPayload::modify_rmw_publisher_options(
-  rmw_publisher_options_t & rmw_publisher_options) const
+  [[maybe_unused]] rmw_publisher_options_t & rmw_publisher_options) const
 {
   // By default, do not mutate the rmw publisher options.
-  (void)rmw_publisher_options;
 }
 
 }  // namespace detail

rclcpp/src/rclcpp/detail/rmw_implementation_specific_subscription_payload.cpp

@@ -23,10 +23,9 @@ namespace detail
 
 void
 RMWImplementationSpecificSubscriptionPayload::modify_rmw_subscription_options(
-  rmw_subscription_options_t & rmw_subscription_options) const
+  [[maybe_unused]] rmw_subscription_options_t & rmw_subscription_options) const
 {
   // By default, do not mutate the rmw subscription options.
-  (void)rmw_subscription_options;
 }
 
 }  // namespace detail

rclcpp/src/rclcpp/detail/utilities.cpp

@@ -31,11 +31,10 @@ namespace detail
 
 std::vector<std::string>
 get_unparsed_ros_arguments(
-  int argc, char const * const * argv,
+  [[maybe_unused]] int argc, char const * const * argv,
   rcl_arguments_t * arguments,
   rcl_allocator_t allocator)
 {
-  (void)argc;
   std::vector<std::string> unparsed_ros_arguments;
   int unparsed_ros_args_count = rcl_arguments_get_count_unparsed_ros(arguments);
   if (unparsed_ros_args_count > 0) {