.. _program_listing_file__tmp_ws_src_rosidl_rosidl_typesupport_introspection_tests_include_rosidl_typesupport_introspection_tests_type_traits.hpp:

Program Listing for File type_traits.hpp
========================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_rosidl_rosidl_typesupport_introspection_tests_include_rosidl_typesupport_introspection_tests_type_traits.hpp>` (``/tmp/ws/src/rosidl/rosidl_typesupport_introspection_tests/include/rosidl_typesupport_introspection_tests/type_traits.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright 2022 Open Source Robotics Foundation, Inc.
   //
   // Licensed under the Apache License, Version 2.0 (the "License");
   // you may not use this file except in compliance with the License.
   // You may obtain a copy of the License at
   //
   //     http://www.apache.org/licenses/LICENSE-2.0
   //
   // Unless required by applicable law or agreed to in writing, software
   // distributed under the License is distributed on an "AS IS" BASIS,
   // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   // See the License for the specific language governing permissions and
   // limitations under the License.
   
   #ifndef ROSIDL_TYPESUPPORT_INTROSPECTION_TESTS__TYPE_TRAITS_HPP_
   #define ROSIDL_TYPESUPPORT_INTROSPECTION_TESTS__TYPE_TRAITS_HPP_
   
   #include <type_traits>
   
   #define EXPRESSION_TYPE(expression) \
     typename std::remove_cv< \
       typename std::remove_reference< \
         decltype(expression)>::type>::type
   
   #define MEMBER_EXPRESSION(type, expression) \
     std::declval<type>().expression
   
   #define MEMBER_EXPRESSION_TYPE(type, expression) \
     EXPRESSION_TYPE(MEMBER_EXPRESSION(type, expression))
   
   #define MEMBER_ITEM_TYPE(type, member) \
     EXPRESSION_TYPE(getitem(MEMBER_EXPRESSION(type, member), 0));
   
   #define DEFINE_HAS_MEMBER_TRAIT(member_name) \
     template<class T, typename = int> \
     struct has_ ## member_name : public std::false_type {}; \
     template<class T> \
     struct has_ ## member_name< \
       T, decltype((void) T::member_name, 0) \
     >: public std::true_type {}
   
   namespace rosidl_typesupport_introspection_tests
   {
   
   // Base definition, to be specialized
   template<typename InterfaceT>
   struct interface_traits;
   
   // Base definition, to be specialized
   template<typename InterfaceT>
   struct introspection_traits;
   
   }  // namespace rosidl_typesupport_introspection_tests
   
   #endif  // ROSIDL_TYPESUPPORT_INTROSPECTION_TESTS__TYPE_TRAITS_HPP_