+<!--
+SPDX-FileCopyrightText: 2023 EfficiOS Inc.
+
+SPDX-License-Identifier: CC-BY-4.0
+-->
+
Userspace RCU Atomic Operations API
===================================
sequence of operations atomically: check if `addr` contains `old`.
If true, then replace the content of `addr` by `new`. Return the
value previously contained by `addr`. This function implies a full
-memory barrier before and after the atomic operation.
+memory barrier before and after the atomic operation on success.
+On failure, no memory order is guaranteed.
```c