diff --git a/include/raii/atomic_shared.hpp b/include/raii/atomic_shared.hpp
new file mode 100644
index 0000000..d73059d
--- /dev/null
+++ b/include/raii/atomic_shared.hpp
@@ -0,0 +1,98 @@
+/**
+ This file is a part of rexy's matrix client
+ Copyright (C) 2019 rexy712
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program. If not, see .
+*/
+
+#ifndef RAII_ATOMIC_SHARED_HPP
+#define RAII_ATOMIC_SHARED_HPP
+
+#include //shared_ptr
+#include //atomic_shared_ptr
+
+#if __cplusplus > 201703L //newer than c++17
+
+namespace raii{
+ template
+ using atomic_shared_ptr = std::atomic>;
+}
+
+#else //c++17 or older
+
+namespace raii{
+
+ template
+ class atomic_shared_ptr
+ {
+ private:
+ static constexpr bool is_always_lock_free = (ATOMIC_POINTER_LOCK_FREE == 2);
+
+ private:
+ std::shared_ptr m_data;
+
+ public:
+ constexpr atomic_shared_ptr(void)noexcept = default;
+ atomic_shared_ptr(std::shared_ptr desired)noexcept:
+ m_data(std::move(desired)){}
+ atomic_shared_ptr(const atomic_shared_ptr&) = delete;
+
+ void operator=(const atomic_shared_ptr&) = delete;
+ void operator=(std::shared_ptr desired)noexcept{
+ store(desired);
+ }
+ bool is_lock_free(void)const noexcept{
+ return std::atomic_is_lock_free(&m_data);
+ }
+ void store(std::shared_ptr desired, std::memory_order order = std::memory_order_seq_cst)noexcept{
+ return std::atomic_store_explicit(&m_data, desired, order);
+ }
+ std::shared_ptr load(std::memory_order order = std::memory_order_seq_cst)const noexcept{
+ return std::atomic_load(&m_data);
+ }
+ operator std::shared_ptr(void)const noexcept{
+ return load();
+ }
+ std::shared_ptr exchange(std::shared_ptr desired, std::memory_order order = std::memory_order_seq_cst)noexcept{
+ return std::atomic_exchange_explicit(&m_data, desired, order);
+ }
+ bool compare_exchange_strong(std::shared_ptr& expected, std::shared_ptr desired, std::memory_order success, std::memory_order failure)noexcept{
+ return std::atomic_compare_exchange_strong_explicit(&m_data, &expected, desired, success, failure);
+ }
+ bool compare_exchange_strong(std::shared_ptr& expected, std::shared_ptr desired, std::memory_order order = std::memory_order_seq_cst)noexcept{
+ std::memory_order fail_order = order;
+ if(fail_order == std::memory_order_acq_rel)
+ fail_order = std::memory_order_acquire;
+ else if(fail_order == std::memory_order_release)
+ fail_order = std::memory_order_relaxed;
+ return compare_exchange_strong(expected, desired, order, fail_order);
+ }
+ bool compare_exchange_weak(std::shared_ptr& expected, std::shared_ptr desired, std::memory_order success, std::memory_order failure)noexcept{
+ return std::atomic_compare_exchange_weak_explicit(&m_data, &expected, desired, success, failure);
+ }
+ bool compare_exchange_weak(std::shared_ptr& expected, std::shared_ptr desired, std::memory_order order = std::memory_order_seq_cst)noexcept{
+ std::memory_order fail_order = order;
+ if(fail_order == std::memory_order_acq_rel)
+ fail_order = std::memory_order_acquire;
+ else if(fail_order == std::memory_order_release)
+ fail_order = std::memory_order_relaxed;
+ return compare_exchange_weak(expected, desired, order, fail_order);
+ }
+ };
+
+}
+
+#endif //__cplusplus
+
+#endif //RAII_ATOMIC_SHARED_HPP