strerror() 函数并没有必要是线程安全的；对于未知值，该函数在静态缓冲区中设置错误消息的格式并将指针返回到该缓冲区。

The strerror() function isn't necessarily thread-safe; for unknown values, it formats an error message in a static buffer and returns a pointer to that buffer.

youdao

你可能会问，为喵我们该忽略回调队列中的未知消息呢，而不是置为处理失败并返回一个错误？

You may ask, why should we ignore unknown messages in the callback queue, rather than failing with an error?

youdao