base/atomic_shared_ptr.hpp

@@ -16,11 +16,26 @@ public:
 
   AtomicSharedPtr() = default;
 
-  void Set(ValueType value) noexcept { atomic_store(&m_wrapped, value); }
-  ValueType Get() const noexcept { return atomic_load(&m_wrapped); }
+// TODO drop this condition and the else branch when Apple and Google will finally
+// also support the full C++20 standard
+// including the partial template specialization of `std::atomic` for `std::shared_ptr<T>`
+// mandated by `P0718R2`:
+// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0718r2.html#3.2
+// The support status can be also tracked at:
+// https://en.cppreference.com/w/cpp/compiler_support/20#cpp_lib_atomic_shared_ptr_201711L
+#if defined(_SHARED_PTR_ATOMIC_H)
+  void Set(ValueType value) noexcept { m_wrapped.store(value); }
+  ValueType Get() const noexcept { return m_wrapped.load(); }
 
 private:
+  std::atomic<ValueType> m_wrapped = std::make_shared<ContentType>();
+#else
+  void Set(ValueType value) noexcept { atomic_store(&m_wrapped, value); }                                                                                                                               
+  ValueType Get() const noexcept { return atomic_load(&m_wrapped); }
+
+ private:
   ValueType m_wrapped = std::make_shared<ContentType>();
+#endif
 
   DISALLOW_COPY_AND_MOVE(AtomicSharedPtr);
 };