.. _program_listing_file_include_rclcpp_wait_set_policies_detail_write_preferring_read_write_lock.hpp:

Program Listing for File write_preferring_read_write_lock.hpp
=============================================================

|exhale_lsh| :ref:`Return to documentation for file <file_include_rclcpp_wait_set_policies_detail_write_preferring_read_write_lock.hpp>` (``include/rclcpp/wait_set_policies/detail/write_preferring_read_write_lock.hpp``)

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

.. code-block:: cpp

   // Copyright 2020 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 RCLCPP__WAIT_SET_POLICIES__DETAIL__WRITE_PREFERRING_READ_WRITE_LOCK_HPP_
   #define RCLCPP__WAIT_SET_POLICIES__DETAIL__WRITE_PREFERRING_READ_WRITE_LOCK_HPP_
   
   #include <condition_variable>
   #include <functional>
   #include <mutex>
   
   #include "rclcpp/visibility_control.hpp"
   
   namespace rclcpp
   {
   namespace wait_set_policies
   {
   namespace detail
   {
   
   
   class WritePreferringReadWriteLock final
   {
   public:
     RCLCPP_PUBLIC
     explicit WritePreferringReadWriteLock(std::function<void()> enter_waiting_function = nullptr);
   
   
     class RCLCPP_PUBLIC ReadMutex
     {
   public:
       void
       lock();
   
       void
       unlock();
   
   protected:
       explicit ReadMutex(WritePreferringReadWriteLock & parent_lock);
   
       WritePreferringReadWriteLock & parent_lock_;
   
       friend class WritePreferringReadWriteLock;
     };
   
   
     class RCLCPP_PUBLIC WriteMutex
     {
   public:
       void
       lock();
   
       void
       unlock();
   
   protected:
       explicit WriteMutex(WritePreferringReadWriteLock & parent_lock);
   
       WritePreferringReadWriteLock & parent_lock_;
   
       friend class WritePreferringReadWriteLock;
     };
   
     RCLCPP_PUBLIC
     ReadMutex &
     get_read_mutex();
   
     RCLCPP_PUBLIC
     WriteMutex &
     get_write_mutex();
   
   protected:
     bool reader_active_ = false;
     std::size_t number_of_writers_waiting_ = 0;
     bool writer_active_ = false;
     std::mutex mutex_;
     std::condition_variable condition_variable_;
     ReadMutex read_mutex_;
     WriteMutex write_mutex_;
     std::function<void()> enter_waiting_function_;
   };
   
   }  // namespace detail
   }  // namespace wait_set_policies
   }  // namespace rclcpp
   
   #endif  // RCLCPP__WAIT_SET_POLICIES__DETAIL__WRITE_PREFERRING_READ_WRITE_LOCK_HPP_