True zero-copy Inter-Process Communication (IPC) in publish/subscribe (pub/sub) middleware such as Robot Operating System 2 (ROS 2) requires subscribers to reference message objects in publisher-owned shared memory. Objects must not be reclaimed while referenced, yet must eventually be reclaimed, with correct handling of crash recovery and Transient Local QoS retention requirements. We propose ipc_shared_ptr, a pub/sub-aware smart pointer for cross-process message lifetime management. ipc_shared_ptr exploits pub/sub structural properties to specialize Birrell's reference listing, limiting global metadata updates to per-subscriber 0<->1 transitions and achieving an order-of-magnitude reduction in global communication over general-purpose distributed reference counting. We analyze the key metadata management tradeoff: scalability versus implementation simplicity. Owner-driven reclaim offers greater scalability, but concurrent membership changes and reclamation decisions produce races that widen the correctness-verification state space. Single-writer achieves structural atomicity, eliminating this complexity at the cost of a centralized bottleneck. iceoryx2 (owner-driven reclaim) and Agnocast -- a true zero-copy ROS 2 IPC middleware sharing the publisher's heap with subscribers and adopting ipc_shared_ptr with single-writer -- embody each architecture. Comparative evaluation at the scale of Autoware -- the largest open-source ROS 2 application -- confirms that single-writer achieves sufficient scalability: at 200 topics, two subscribers per topic and 100 Hz, Agnocast's E2E p99.9 is 2.9x lower than iceoryx2's, justifying implementation simplicity over owner-driven reclaim.

翻译：在发布/订阅中间件（如机器人操作系统2）中实现真正的零拷贝进程间通信，要求订阅者引用发布者所拥有的共享内存中的消息对象。被引用的对象必须在引用期间不被回收，同时最终仍需被回收，并正确应对崩溃恢复与瞬态本地QoS保留需求。我们提出ipc_shared_ptr，一种面向发布/订阅感知的跨进程消息生命周期管理智能指针。ipc_shared_ptr利用发布/订阅的结构特性对Birrell引用列表进行专门化，将全局元数据更新限制为每个订阅者的0<->1状态转换，相较于通用分布式引用计数，实现了全局通信量一个数量级的降低。我们分析了关键元数据管理权衡：可扩展性与实现简洁性。拥有者驱动的回收具有更高可扩展性，但并发成员变更与回收决策会产生竞态，从而扩大正确性验证的状态空间。单写入者实现了结构原子性，以集中式瓶颈为代价消除了这一复杂性。iceoryx2（拥有者驱动回收）与Agnocast——一种真正零拷贝的ROS 2 IPC中间件，共享发布者堆空间并采用单写入者ipc_shared_ptr——分别体现了两种架构。基于最大开源ROS 2应用Autoware规模的对比评估证实，单写入者能达到足够的可扩展性：在200个主题、每主题2个订阅者且频率100Hz条件下，Agnocast的端到端p99.9延迟比iceoryx2低2.9倍，验证了实现简洁性相对于拥有者驱动回收的合理性。