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<ol class="chapter"><li class="chapter-item affix "><a href="../../about-book.html">关于本书</a></li><li class="chapter-item affix "><a href="../../into-rust.html">进入 Rust 编程世界</a></li><li class="chapter-item affix "><a href="../../first-try/sth-you-should-not-do.html">避免从入门到放弃</a></li><li class="chapter-item affix "><a href="../../community.html">社区和锈书</a></li><li class="chapter-item affix "><li class="part-title">Rust 语言基础学习</li><li class="spacer"></li><li class="chapter-item "><a href="../../first-try/intro.html"><strong aria-hidden="true">1.</strong> 寻找牛刀，以便小试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../first-try/installation.html"><strong aria-hidden="true">1.1.</strong> 安装 Rust 环境</a></li><li class="chapter-item "><a href="../../first-try/editor.html"><strong aria-hidden="true">1.2.</strong> 墙推 VSCode!</a></li><li class="chapter-item "><a href="../../first-try/cargo.html"><strong aria-hidden="true">1.3.</strong> 认识 Cargo</a></li><li class="chapter-item "><a href="../../first-try/hello-world.html"><strong aria-hidden="true">1.4.</strong> 不仅仅是 Hello world</a></li><li class="chapter-item "><a href="../../first-try/slowly-downloading.html"><strong aria-hidden="true">1.5.</strong> 下载依赖太慢了？</a></li></ol></li><li class="chapter-item "><a href="../../basic/intro.html"><strong aria-hidden="true">2.</strong> Rust 基础入门</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/variable.html"><strong aria-hidden="true">2.1.</strong> 变量绑定与解构</a></li><li class="chapter-item "><a href="../../basic/base-type/index.html"><strong aria-hidden="true">2.2.</strong> 基本类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/base-type/numbers.html"><strong aria-hidden="true">2.2.1.</strong> 数值类型</a></li><li class="chapter-item "><a href="../../basic/base-type/char-bool.html"><strong aria-hidden="true">2.2.2.</strong> 字符、布尔、单元类型</a></li><li class="chapter-item "><a href="../../basic/base-type/statement-expression.html"><strong aria-hidden="true">2.2.3.</strong> 语句与表达式</a></li><li class="chapter-item "><a href="../../basic/base-type/function.html"><strong aria-hidden="true">2.2.4.</strong> 函数</a></li></ol></li><li class="chapter-item "><a href="../../basic/ownership/index.html"><strong aria-hidden="true">2.3.</strong> 所有权和借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/ownership/ownership.html"><strong aria-hidden="true">2.3.1.</strong> 所有权</a></li><li class="chapter-item "><a href="../../basic/ownership/borrowing.html"><strong aria-hidden="true">2.3.2.</strong> 引用与借用</a></li></ol></li><li class="chapter-item "><a href="../../basic/compound-type/intro.html"><strong aria-hidden="true">2.4.</strong> 复合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/compound-type/string-slice.html"><strong aria-hidden="true">2.4.1.</strong> 字符串与切片</a></li><li class="chapter-item "><a href="../../basic/compound-type/tuple.html"><strong aria-hidden="true">2.4.2.</strong> 元组</a></li><li class="chapter-item "><a href="../../basic/compound-type/struct.html"><strong aria-hidden="true">2.4.3.</strong> 结构体</a></li><li class="chapter-item "><a href="../../basic/compound-type/enum.html"><strong aria-hidden="true">2.4.4.</strong> 枚举</a></li><li class="chapter-item "><a href="../../basic/compound-type/array.html"><strong aria-hidden="true">2.4.5.</strong> 数组</a></li></ol></li><li class="chapter-item "><a href="../../basic/flow-control.html"><strong aria-hidden="true">2.5.</strong> 流程控制</a></li><li class="chapter-item "><a href="../../basic/match-pattern/intro.html"><strong aria-hidden="true">2.6.</strong> 模式匹配</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/match-pattern/match-if-let.html"><strong aria-hidden="true">2.6.1.</strong> match 和 if let</a></li><li class="chapter-item "><a href="../../basic/match-pattern/option.html"><strong aria-hidden="true">2.6.2.</strong> 解构 Option</a></li><li class="chapter-item "><a href="../../basic/match-pattern/pattern-match.html"><strong aria-hidden="true">2.6.3.</strong> 模式适用场景</a></li><li class="chapter-item "><a href="../../basic/match-pattern/all-patterns.html"><strong aria-hidden="true">2.6.4.</strong> 全模式列表</a></li></ol></li><li class="chapter-item "><a href="../../basic/method.html"><strong aria-hidden="true">2.7.</strong> 方法 Method</a></li><li class="chapter-item "><a href="../../basic/trait/intro.html"><strong aria-hidden="true">2.8.</strong> 泛型和特征</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/trait/generic.html"><strong aria-hidden="true">2.8.1.</strong> 泛型 Generics</a></li><li class="chapter-item "><a href="../../basic/trait/trait.html"><strong aria-hidden="true">2.8.2.</strong> 特征 Trait</a></li><li class="chapter-item "><a href="../../basic/trait/trait-object.html"><strong aria-hidden="true">2.8.3.</strong> 特征对象</a></li><li class="chapter-item "><a href="../../basic/trait/advance-trait.html"><strong aria-hidden="true">2.8.4.</strong> 进一步深入特征</a></li></ol></li><li class="chapter-item "><a href="../../basic/collections/intro.html"><strong aria-hidden="true">2.9.</strong> 集合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/collections/vector.html"><strong aria-hidden="true">2.9.1.</strong> 动态数组 Vector</a></li><li class="chapter-item "><a href="../../basic/collections/hashmap.html"><strong aria-hidden="true">2.9.2.</strong> KV 存储 HashMap</a></li></ol></li><li class="chapter-item "><a href="../../basic/lifetime.html"><strong aria-hidden="true">2.10.</strong> 认识生命周期</a></li><li class="chapter-item "><a href="../../basic/result-error/intro.html"><strong aria-hidden="true">2.11.</strong> 返回值和错误处理</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/result-error/panic.html"><strong aria-hidden="true">2.11.1.</strong> panic! 深入剖析</a></li><li class="chapter-item "><a href="../../basic/result-error/result.html"><strong aria-hidden="true">2.11.2.</strong> 返回值 Result 和?</a></li></ol></li><li class="chapter-item "><a href="../../basic/crate-module/intro.html"><strong aria-hidden="true">2.12.</strong> 包和模块</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/crate-module/crate.html"><strong aria-hidden="true">2.12.1.</strong> 包 Crate</a></li><li class="chapter-item "><a href="../../basic/crate-module/module.html"><strong aria-hidden="true">2.12.2.</strong> 模块 Module</a></li><li class="chapter-item "><a href="../../basic/crate-module/use.html"><strong aria-hidden="true">2.12.3.</strong> 使用 use 引入模块及受限可见性</a></li></ol></li><li class="chapter-item "><a href="../../basic/comment.html"><strong aria-hidden="true">2.13.</strong> 注释和文档</a></li><li class="chapter-item "><a href="../../basic/formatted-output.html"><strong aria-hidden="true">2.14.</strong> 格式化输出</a></li></ol></li><li class="chapter-item "><a href="../../basic-practice/intro.html"><strong aria-hidden="true">3.</strong> 入门实战：文件搜索工具</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic-practice/base-features.html"><strong aria-hidden="true">3.1.</strong> 基本功能</a></li><li class="chapter-item "><a href="../../basic-practice/refactoring.html"><strong aria-hidden="true">3.2.</strong> 增加模块化和错误处理</a></li><li class="chapter-item "><a href="../../basic-practice/tests.html"><strong aria-hidden="true">3.3.</strong> 测试驱动开发</a></li><li class="chapter-item "><a href="../../basic-practice/envs.html"><strong aria-hidden="true">3.4.</strong> 使用环境变量</a></li><li class="chapter-item "><a href="../../basic-practice/stderr.html"><strong aria-hidden="true">3.5.</strong> 重定向错误信息的输出</a></li><li class="chapter-item "><a href="../../basic-practice/iterators.html"><strong aria-hidden="true">3.6.</strong> 使用迭代器来改进程序(可选)</a></li></ol></li><li class="chapter-item "><li class="part-title">Rust 语言进阶学习</li><li class="spacer"></li><li class="chapter-item expanded "><a href="../../advance/intro.html"><strong aria-hidden="true">4.</strong> Rust 高级进阶</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/lifetime/intro.html"><strong aria-hidden="true">4.1.</strong> 生命周期</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/lifetime/advance.html"><strong aria-hidden="true">4.1.1.</strong> 深入生命周期</a></li><li class="chapter-item "><a href="../../advance/lifetime/static.html"><strong aria-hidden="true">4.1.2.</strong> &amp;'static 和 T: 'static</a></li></ol></li><li class="chapter-item "><a href="../../advance/functional-programing/intro.html"><strong aria-hidden="true">4.2.</strong> 函数式编程: 闭包、迭代器</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/functional-programing/closure.html"><strong aria-hidden="true">4.2.1.</strong> 闭包 Closure</a></li><li class="chapter-item "><a href="../../advance/functional-programing/iterator.html"><strong aria-hidden="true">4.2.2.</strong> 迭代器 Iterator</a></li></ol></li><li class="chapter-item "><a href="../../advance/into-types/intro.html"><strong aria-hidden="true">4.3.</strong> 深入类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/into-types/converse.html"><strong aria-hidden="true">4.3.1.</strong> 类型转换</a></li><li class="chapter-item "><a href="../../advance/into-types/custom-type.html"><strong aria-hidden="true">4.3.2.</strong> newtype 和 类型别名</a></li><li class="chapter-item "><a href="../../advance/into-types/sized.html"><strong aria-hidden="true">4.3.3.</strong> Sized 和不定长类型 DST</a></li><li class="chapter-item "><a href="../../advance/into-types/enum-int.html"><strong aria-hidden="true">4.3.4.</strong> 枚举和整数</a></li></ol></li><li class="chapter-item "><a href="../../advance/smart-pointer/intro.html"><strong aria-hidden="true">4.4.</strong> 智能指针</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/smart-pointer/box.html"><strong aria-hidden="true">4.4.1.</strong> Box堆对象分配</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/deref.html"><strong aria-hidden="true">4.4.2.</strong> Deref 解引用</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/drop.html"><strong aria-hidden="true">4.4.3.</strong> Drop 释放资源</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/rc-arc.html"><strong aria-hidden="true">4.4.4.</strong> Rc 与 Arc 实现 1vN 所有权机制</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/cell-refcell.html"><strong aria-hidden="true">4.4.5.</strong> Cell 与 RefCell 内部可变性</a></li></ol></li><li class="chapter-item "><a href="../../advance/circle-self-ref/intro.html"><strong aria-hidden="true">4.5.</strong> 循环引用与自引用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/circle-self-ref/circle-reference.html"><strong aria-hidden="true">4.5.1.</strong> Weak 与循环引用</a></li><li class="chapter-item "><a href="../../advance/circle-self-ref/self-referential.html"><strong aria-hidden="true">4.5.2.</strong> 结构体中的自引用</a></li></ol></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/intro.html"><strong aria-hidden="true">4.6.</strong> 多线程并发编程</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/concurrency-with-threads/concurrency-parallelism.html"><strong aria-hidden="true">4.6.1.</strong> 并发和并行</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/thread.html"><strong aria-hidden="true">4.6.2.</strong> 使用多线程</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/message-passing.html"><strong aria-hidden="true">4.6.3.</strong> 线程同步：消息传递</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/sync1.html"><strong aria-hidden="true">4.6.4.</strong> 线程同步：锁、Condvar 和信号量</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/sync2.html"><strong aria-hidden="true">4.6.5.</strong> 线程同步：Atomic 原子操作与内存顺序</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/send-sync.html"><strong aria-hidden="true">4.6.6.</strong> 基于 Send 和 Sync 的线程安全</a></li></ol></li><li class="chapter-item "><a href="../../advance/global-variable.html"><strong aria-hidden="true">4.7.</strong> 全局变量</a></li><li class="chapter-item "><a href="../../advance/errors.html"><strong aria-hidden="true">4.8.</strong> 错误处理</a></li><li class="chapter-item expanded "><a href="../../advance/unsafe/intro.html"><strong aria-hidden="true">4.9.</strong> Unsafe Rust</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../advance/unsafe/superpowers.html" class="active"><strong aria-hidden="true">4.9.1.</strong> 五种兵器</a></li><li class="chapter-item "><a href="../../advance/unsafe/inline-asm.html"><strong aria-hidden="true">4.9.2.</strong> 内联汇编</a></li></ol></li><li class="chapter-item "><a href="../../advance/macro.html"><strong aria-hidden="true">4.10.</strong> Macro 宏编程</a></li><li class="chapter-item "><a href="../../advance/async/intro.html"><strong aria-hidden="true">4.11.</strong> async/await 异步编程</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/async/getting-started.html"><strong aria-hidden="true">4.11.1.</strong> async 编程入门</a></li><li class="chapter-item "><a href="../../advance/async/future-excuting.html"><strong aria-hidden="true">4.11.2.</strong> 底层探秘: Future 执行与任务调度</a></li><li class="chapter-item "><a href="../../advance/async/pin-unpin.html"><strong aria-hidden="true">4.11.3.</strong> 定海神针 Pin 和 Unpin</a></li><li class="chapter-item "><a href="../../advance/async/async-await.html"><strong aria-hidden="true">4.11.4.</strong> async/await 和 Stream 流处理</a></li><li class="chapter-item "><a href="../../advance/async/multi-futures-simultaneous.html"><strong aria-hidden="true">4.11.5.</strong> 同时运行多个 Future</a></li><li class="chapter-item "><a href="../../advance/async/pain-points-and-workarounds.html"><strong aria-hidden="true">4.11.6.</strong> 一些疑难问题的解决办法</a></li><li class="chapter-item "><a href="../../advance/async/web-server.html"><strong aria-hidden="true">4.11.7.</strong> 实践应用：Async Web 服务器</a></li></ol></li></ol></li><li class="chapter-item "><a href="../../advance-practice1/intro.html"><strong aria-hidden="true">5.</strong> 进阶实战1: 实现一个 web 服务器</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance-practice1/web-server.html"><strong aria-hidden="true">5.1.</strong> 单线程版本</a></li><li class="chapter-item "><a href="../../advance-practice1/multi-threads.html"><strong aria-hidden="true">5.2.</strong> 多线程版本</a></li><li class="chapter-item "><a href="../../advance-practice1/graceful-shutdown.html"><strong aria-hidden="true">5.3.</strong> 优雅关闭和资源清理</a></li></ol></li><li class="chapter-item "><a href="../../advance-practice/intro.html"><strong aria-hidden="true">6.</strong> 进阶实战2: 实现一个简单 Redis</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance-practice/overview.html"><strong aria-hidden="true">6.1.</strong> tokio 概览</a></li><li class="chapter-item "><a href="../../advance-practice/getting-startted.html"><strong aria-hidden="true">6.2.</strong> 使用初印象</a></li><li class="chapter-item "><a href="../../advance-practice/spawning.html"><strong aria-hidden="true">6.3.</strong> 创建异步任务</a></li><li class="chapter-item "><a href="../../advance-practice/shared-state.html"><strong aria-hidden="true">6.4.</strong> 共享状态</a></li><li class="chapter-item "><a href="../../advance-practice/channels.html"><strong aria-hidden="true">6.5.</strong> 消息传递</a></li><li class="chapter-item "><a href="../../advance-practice/io.html"><strong aria-hidden="true">6.6.</strong> I/O</a></li><li class="chapter-item "><a href="../../advance-practice/frame.html"><strong aria-hidden="true">6.7.</strong> 解析数据帧</a></li><li class="chapter-item "><a href="../../advance-practice/async.html"><strong aria-hidden="true">6.8.</strong> 深入 async</a></li><li class="chapter-item "><a href="../../advance-practice/select.html"><strong aria-hidden="true">6.9.</strong> select</a></li><li class="chapter-item "><a href="../../advance-practice/stream.html"><strong aria-hidden="true">6.10.</strong> 类似迭代器的 Stream</a></li><li class="chapter-item "><a href="../../advance-practice/graceful-shutdown.html"><strong aria-hidden="true">6.11.</strong> 优雅的关闭</a></li><li class="chapter-item "><a href="../../advance-practice/bridging-with-sync.html"><strong aria-hidden="true">6.12.</strong> 异步跟同步共存</a></li></ol></li><li class="chapter-item "><a href="../../difficulties/intro.html"><strong aria-hidden="true">7.</strong> Rust 难点攻关</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../difficulties/slice.html"><strong aria-hidden="true">7.1.</strong> 切片和切片引用</a></li><li class="chapter-item "><a href="../../difficulties/eq.html"><strong aria-hidden="true">7.2.</strong> Eq 和 PartialEq</a></li><li class="chapter-item "><a href="../../difficulties/string.html"><strong aria-hidden="true">7.3.</strong> String、&amp;str 和 str TODO</a></li><li class="chapter-item "><a href="../../difficulties/lifetime.html"><strong aria-hidden="true">7.4.</strong> 作用域、生命周期和 NLL TODO</a></li><li class="chapter-item "><a href="../../difficulties/move-copy.html"><strong aria-hidden="true">7.5.</strong> move、Copy 和 Clone TODO</a></li><li class="chapter-item "><a href="../../advance/difficulties/pointer.html"><strong aria-hidden="true">7.6.</strong> 裸指针、引用和智能指针 TODO</a></li></ol></li><li class="chapter-item "><li class="part-title">常用工具链</li><li class="spacer"></li><li class="chapter-item "><a href="../../test/intro.html"><strong aria-hidden="true">8.</strong> 自动化测试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../test/write-tests.html"><strong aria-hidden="true">8.1.</strong> 编写测试及控制执行</a></li><li class="chapter-item "><a href="../../test/unit-integration-test.html"><strong aria-hidden="true">8.2.</strong> 单元测试和集成测试</a></li><li class="chapter-item "><a href="../../test/assertion.html"><strong aria-hidden="true">8.3.</strong> 断言 assertion</a></li><li class="chapter-item "><a href="../../test/ci.html"><strong aria-hidden="true">8.4.</strong> 用 GitHub Actions 进行持续集成</a></li><li class="chapter-item "><a href="../../test/benchmark.html"><strong aria-hidden="true">8.5.</strong> 基准测试 benchmark</a></li></ol></li><li class="chapter-item "><a href="../../cargo/intro.html"><strong aria-hidden="true">9.</strong> Cargo 使用指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/getting-started.html"><strong aria-hidden="true">9.1.</strong> 上手使用</a></li><li class="chapter-item "><a href="../../cargo/guide/intro.html"><strong aria-hidden="true">9.2.</strong> 基础指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/guide/why-exist.html"><strong aria-hidden="true">9.2.1.</strong> 为何会有 Cargo</a></li><li class="chapter-item "><a href="../../cargo/guide/download-package.html"><strong aria-hidden="true">9.2.2.</strong> 下载并构建 Package</a></li><li class="chapter-item "><a href="../../cargo/guide/dependencies.html"><strong aria-hidden="true">9.2.3.</strong> 添加依赖</a></li><li class="chapter-item "><a href="../../cargo/guide/package-layout.html"><strong aria-hidden="true">9.2.4.</strong> Package 目录结构</a></li><li class="chapter-item "><a href="../../cargo/guide/cargo-toml-lock.html"><strong aria-hidden="true">9.2.5.</strong> Cargo.toml vs Cargo.lock</a></li><li class="chapter-item "><a href="../../cargo/guide/tests-ci.html"><strong aria-hidden="true">9.2.6.</strong> 测试和 CI</a></li><li class="chapter-item "><a href="../../cargo/guide/cargo-cache.html"><strong aria-hidden="true">9.2.7.</strong> Cargo 缓存</a></li><li class="chapter-item "><a href="../../cargo/guide/build-cache.html"><strong aria-hidden="true">9.2.8.</strong> Build 缓存</a></li></ol></li><li class="chapter-item "><a href="../../cargo/reference/intro.html"><strong aria-hidden="true">9.3.</strong> 进阶指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/reference/specify-deps.html"><strong aria-hidden="true">9.3.1.</strong> 指定依赖项</a></li><li class="chapter-item "><a href="../../cargo/reference/deps-overriding.html"><strong aria-hidden="true">9.3.2.</strong> 依赖覆盖</a></li><li class="chapter-item "><a href="../../cargo/reference/manifest.html"><strong aria-hidden="true">9.3.3.</strong> Cargo.toml 清单详解</a></li><li class="chapter-item "><a href="../../cargo/reference/cargo-target.html"><strong aria-hidden="true">9.3.4.</strong> Cargo Target</a></li><li class="chapter-item "><a href="../../cargo/reference/workspaces.html"><strong aria-hidden="true">9.3.5.</strong> 工作空间 Workspace</a></li><li class="chapter-item "><a href="../../cargo/reference/features/intro.html"><strong aria-hidden="true">9.3.6.</strong> 条件编译 Features</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/reference/features/examples.html"><strong aria-hidden="true">9.3.6.1.</strong> Features 示例</a></li></ol></li><li class="chapter-item "><a href="../../cargo/reference/profiles.html"><strong aria-hidden="true">9.3.7.</strong> 发布配置 Profile</a></li><li class="chapter-item "><a href="../../cargo/reference/configuration.html"><strong aria-hidden="true">9.3.8.</strong> 通过 config.toml 对 Cargo 进行配置</a></li><li class="chapter-item "><a href="../../cargo/reference/publishing-on-crates.io.html"><strong aria-hidden="true">9.3.9.</strong> 发布到 crates.io</a></li><li class="chapter-item "><a href="../../cargo/reference/build-script/intro.html"><strong aria-hidden="true">9.3.10.</strong> 构建脚本 build.rs</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/reference/build-script/examples.html"><strong aria-hidden="true">9.3.10.1.</strong> 构建脚本示例</a></li></ol></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">开发实践</li><li class="spacer"></li><li class="chapter-item "><a href="../../usecases/intro.html"><strong aria-hidden="true">10.</strong> 企业落地实践</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../usecases/aws-rust.html"><strong aria-hidden="true">10.1.</strong> AWS 为何这么喜欢 Rust?</a></li></ol></li><li class="chapter-item "><a href="../../logs/intro.html"><strong aria-hidden="true">11.</strong> 日志和监控</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../logs/about-log.html"><strong aria-hidden="true">11.1.</strong> 日志详解</a></li><li class="chapter-item "><a href="../../logs/log.html"><strong aria-hidden="true">11.2.</strong> 日志门面 log</a></li><li class="chapter-item "><a href="../../logs/tracing.html"><strong aria-hidden="true">11.3.</strong> 使用 tracing 记录日志</a></li><li class="chapter-item "><a href="../../logs/tracing-logger.html"><strong aria-hidden="true">11.4.</strong> 自定义 tracing 的输出格式</a></li><li class="chapter-item "><a href="../../logs/observe/intro.html"><strong aria-hidden="true">11.5.</strong> 监控</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../logs/observe/about-observe.html"><strong aria-hidden="true">11.5.1.</strong> 可观测性</a></li><li class="chapter-item "><a href="../../logs/observe/trace.html"><strong aria-hidden="true">11.5.2.</strong> 分布式追踪</a></li></ol></li></ol></li><li class="chapter-item "><a href="../../practice/intro.html"><strong aria-hidden="true">12.</strong> Rust 最佳实践</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../practice/third-party-libs.html"><strong aria-hidden="true">12.1.</strong> 日常开发三方库精选</a></li><li class="chapter-item "><a href="../../practice/naming.html"><strong aria-hidden="true">12.2.</strong> 命名规范</a></li><li class="chapter-item "><a href="../../practice/interview.html"><strong aria-hidden="true">12.3.</strong> 面试经验</a></li><li class="chapter-item "><a href="../../practice/best-pratice.html"><strong aria-hidden="true">12.4.</strong> 代码开发实践 todo</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/intro.html"><strong aria-hidden="true">13.</strong> 手把手带你实现链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/do-we-need-it.html"><strong aria-hidden="true">13.1.</strong> 我们到底需不需要链表</a></li><li class="chapter-item "><a href="../../too-many-lists/bad-stack/intro.html"><strong aria-hidden="true">13.2.</strong> 不太优秀的单向链表：栈</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/bad-stack/layout.html"><strong aria-hidden="true">13.2.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../../too-many-lists/bad-stack/basic-operations.html"><strong aria-hidden="true">13.2.2.</strong> 基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/bad-stack/final-code.html"><strong aria-hidden="true">13.2.3.</strong> 最后实现</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/intro.html"><strong aria-hidden="true">13.3.</strong> 还可以的单向链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/ok-stack/type-optimizing.html"><strong aria-hidden="true">13.3.1.</strong> 优化类型定义</a></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/peek.html"><strong aria-hidden="true">13.3.2.</strong> 定义 Peek 函数</a></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/iter.html"><strong aria-hidden="true">13.3.3.</strong> IntoIter 和 Iter</a></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/itermut.html"><strong aria-hidden="true">13.3.4.</strong> IterMut 以及完整代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/persistent-stack/intro.html"><strong aria-hidden="true">13.4.</strong> 持久化单向链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/persistent-stack/layout.html"><strong aria-hidden="true">13.4.1.</strong> 数据布局和基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/persistent-stack/drop-arc.html"><strong aria-hidden="true">13.4.2.</strong> Drop、Arc 及完整代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/deque/intro.html"><strong aria-hidden="true">13.5.</strong> 不咋样的双端队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/deque/layout.html"><strong aria-hidden="true">13.5.1.</strong> 数据布局和基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/peek.html"><strong aria-hidden="true">13.5.2.</strong> Peek</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/symmetric.html"><strong aria-hidden="true">13.5.3.</strong> 基本操作的对称镜像</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/iterator.html"><strong aria-hidden="true">13.5.4.</strong> 迭代器</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/final-code.html"><strong aria-hidden="true">13.5.5.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/intro.html"><strong aria-hidden="true">13.6.</strong> 不错的 unsafe 队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/layout.html"><strong aria-hidden="true">13.6.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/basics.html"><strong aria-hidden="true">13.6.2.</strong> 基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/miri.html"><strong aria-hidden="true">13.6.3.</strong> Miri</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/stacked-borrow.html"><strong aria-hidden="true">13.6.4.</strong> 栈借用</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/testing-stacked-borrow.html"><strong aria-hidden="true">13.6.5.</strong> 测试栈借用</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/layout2.html"><strong aria-hidden="true">13.6.6.</strong> 数据布局 2</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/extra-junk.html"><strong aria-hidden="true">13.6.7.</strong> 额外的操作</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/final-code.html"><strong aria-hidden="true">13.6.8.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/intro.html"><strong aria-hidden="true">13.7.</strong> 使用高级技巧实现链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/unsafe-deque.html"><strong aria-hidden="true">13.7.1.</strong> 生产级可用的双向链表</a></li><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/double-singly.html"><strong aria-hidden="true">13.7.2.</strong> 双单向链表</a></li><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/stack-allocated.html"><strong aria-hidden="true">13.7.3.</strong> 栈上的链表</a></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">攻克编译错误</li><li class="spacer"></li><li class="chapter-item "><a href="../../compiler/intro.html"><strong aria-hidden="true">14.</strong> 征服编译错误</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/intro.html"><strong aria-hidden="true">14.1.</strong> 对抗编译检查</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/intro.html"><strong aria-hidden="true">14.1.1.</strong> 生命周期</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/too-long1.html"><strong aria-hidden="true">14.1.1.1.</strong> 生命周期过大-01</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/too-long2.html"><strong aria-hidden="true">14.1.1.2.</strong> 生命周期过大-02</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/loop.html"><strong aria-hidden="true">14.1.1.3.</strong> 循环中的生命周期</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/closure-with-static.html"><strong aria-hidden="true">14.1.1.4.</strong> 闭包碰到特征对象-01</a></li></ol></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/borrowing/intro.html"><strong aria-hidden="true">14.1.2.</strong> 重复借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/borrowing/ref-exist-in-out-fn.html"><strong aria-hidden="true">14.1.2.1.</strong> 同时在函数内外使用引用</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/borrowing/borrow-distinct-fields-of-struct.html"><strong aria-hidden="true">14.1.2.2.</strong> 智能指针引起的重复借用错误</a></li></ol></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/unconstrained.html"><strong aria-hidden="true">14.1.3.</strong> 类型未限制(todo)</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/phantom-data.html"><strong aria-hidden="true">14.1.4.</strong> 幽灵数据(todo)</a></li></ol></li><li class="chapter-item "><a href="../../compiler/pitfalls/index.html"><strong aria-hidden="true">14.2.</strong> Rust 常见陷阱</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/pitfalls/use-vec-in-for.html"><strong aria-hidden="true">14.2.1.</strong> for 循环中使用外部数组</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/stack-overflow.html"><strong aria-hidden="true">14.2.2.</strong> 线程类型导致的栈溢出</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/arithmetic-overflow.html"><strong aria-hidden="true">14.2.3.</strong> 算术溢出导致的 panic</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/closure-with-lifetime.html"><strong aria-hidden="true">14.2.4.</strong> 闭包中奇怪的生命周期</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/the-disabled-mutability.html"><strong aria-hidden="true">14.2.5.</strong> 可变变量不可变？</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/multiple-mutable-references.html"><strong aria-hidden="true">14.2.6.</strong> 可变借用失败引发的深入思考</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/lazy-iterators.html"><strong aria-hidden="true">14.2.7.</strong> 不太勤快的迭代器</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/weird-ranges.html"><strong aria-hidden="true">14.2.8.</strong> 奇怪的序列 x..y</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/iterator-everywhere.html"><strong aria-hidden="true">14.2.9.</strong> 无处不在的迭代器</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/main-with-channel-blocked.html"><strong aria-hidden="true">14.2.10.</strong> 线程间传递消息导致主线程无法结束</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/utf8-performance.html"><strong aria-hidden="true">14.2.11.</strong> 警惕 UTF-8 引发的性能隐患</a></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">性能优化</li><li class="spacer"></li><li class="chapter-item "><a href="../../profiling/intro.html"><strong aria-hidden="true">15.</strong> Rust 性能优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/memory/intro.html"><strong aria-hidden="true">15.1.</strong> 深入内存 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/memory/pointer-ref.html"><strong aria-hidden="true">15.1.1.</strong> 指针和引用 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/uninit.html"><strong aria-hidden="true">15.1.2.</strong> 未初始化内存 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/allocation.html"><strong aria-hidden="true">15.1.3.</strong> 内存分配 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/layout.html"><strong aria-hidden="true">15.1.4.</strong> 内存布局 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/virtual.html"><strong aria-hidden="true">15.1.5.</strong> 虚拟内存 todo</a></li></ol></li><li class="chapter-item "><a href="../../profiling/performance/intro.html"><strong aria-hidden="true">15.2.</strong> 性能调优 doing</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/performance/string.html"><strong aria-hidden="true">15.2.1.</strong> 字符串操作性能</a></li><li class="chapter-item "><a href="../../profiling/performance/deep-into-move.html"><strong aria-hidden="true">15.2.2.</strong> 深入理解 move</a></li><li class="chapter-item "><a href="../../profiling/performance/early-optimise.html"><strong aria-hidden="true">15.2.3.</strong> 糟糕的提前优化 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/clone-copy.html"><strong aria-hidden="true">15.2.4.</strong> Clone 和 Copy todo</a></li><li class="chapter-item "><a href="../../profiling/performance/runtime-check.html"><strong aria-hidden="true">15.2.5.</strong> 减少 Runtime check(todo)</a></li><li class="chapter-item "><a href="../../profiling/performance/cpu-cache.html"><strong aria-hidden="true">15.2.6.</strong> CPU 缓存性能优化 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/calculate.html"><strong aria-hidden="true">15.2.7.</strong> 计算性能优化 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/heap-stack.html"><strong aria-hidden="true">15.2.8.</strong> 堆和栈 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/allocator.html"><strong aria-hidden="true">15.2.9.</strong> 内存 allocator todo</a></li><li class="chapter-item "><a href="../../profiling/performance/tools.html"><strong aria-hidden="true">15.2.10.</strong> 常用性能测试工具 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/enum.html"><strong aria-hidden="true">15.2.11.</strong> Enum 内存优化 todo</a></li></ol></li><li class="chapter-item "><a href="../../profiling/compiler/intro.html"><strong aria-hidden="true">15.3.</strong> 编译优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/compiler/llvm.html"><strong aria-hidden="true">15.3.1.</strong> LLVM todo</a></li><li class="chapter-item "><a href="../../profiling/compiler/attributes.html"><strong aria-hidden="true">15.3.2.</strong> 常见属性标记 todo</a></li><li class="chapter-item "><a href="../../profiling/compiler/speed-up.html"><strong aria-hidden="true">15.3.3.</strong> 提升编译速度 todo</a></li><li class="chapter-item "><a href="../../profiling/compiler/optimization/intro.html"><strong aria-hidden="true">15.3.4.</strong> 编译器优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/compiler/optimization/option.html"><strong aria-hidden="true">15.3.4.1.</strong> Option 枚举 todo</a></li></ol></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">附录</li><li class="spacer"></li><li class="chapter-item "><div><strong aria-hidden="true">16.</strong> Appendix</div><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../appendix/keywords.html"><strong aria-hidden="true">16.1.</strong> 关键字</a></li><li class="chapter-item "><a href="../../appendix/operators.html"><strong aria-hidden="true">16.2.</strong> 运算符与符号</a></li><li class="chapter-item "><a href="../../appendix/expressions.html"><strong aria-hidden="true">16.3.</strong> 表达式</a></li><li class="chapter-item "><a href="../../appendix/derive.html"><strong aria-hidden="true">16.4.</strong> 派生特征 trait</a></li><li class="chapter-item "><a href="../../appendix/prelude.html"><strong aria-hidden="true">16.5.</strong> prelude 模块 todo</a></li><li class="chapter-item "><a href="../../appendix/rust-version.html"><strong aria-hidden="true">16.6.</strong> Rust 版本说明</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/intro.html"><strong aria-hidden="true">16.7.</strong> Rust 历次版本更新解读</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../appendix/rust-versions/1.58.html"><strong aria-hidden="true">16.7.1.</strong> 1.58</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.59.html"><strong aria-hidden="true">16.7.2.</strong> 1.59</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.60.html"><strong aria-hidden="true">16.7.3.</strong> 1.60</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.61.html"><strong aria-hidden="true">16.7.4.</strong> 1.61</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.62.html"><strong aria-hidden="true">16.7.5.</strong> 1.62</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.63.html"><strong aria-hidden="true">16.7.6.</strong> 1.63</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.64.html"><strong aria-hidden="true">16.7.7.</strong> 1.64</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.65.html"><strong aria-hidden="true">16.7.8.</strong> 1.65</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.66.html"><strong aria-hidden="true">16.7.9.</strong> 1.66</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.67.html"><strong aria-hidden="true">16.7.10.</strong> 1.67</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.68.html"><strong aria-hidden="true">16.7.11.</strong> 1.68</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.69.html"><strong aria-hidden="true">16.7.12.</strong> 1.69</a></li></ol></li></ol></li></ol>
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<main>
<h1 id="五种兵器"><a class="header" href="#五种兵器">五种兵器</a></h1>
<p>古龙有一部小说，名为&quot;七种兵器&quot;，其中每一种都精妙绝伦，令人闻风丧胆，而 <code>unsafe</code> 也有五种兵器，它们可以让你拥有其它代码无法实现的能力，同时它们也像七种兵器一样令人闻风丧胆，下面一起来看看庐山真面目。</p>
<h2 id="解引用裸指针"><a class="header" href="#解引用裸指针">解引用裸指针</a></h2>
<p>裸指针(raw pointer，又称原生指针) 在功能上跟引用类似，同时它也需要显式地注明可变性。但是又和引用有所不同，裸指针长这样: <code>*const T</code> 和 <code>*mut T</code>，它们分别代表了不可变和可变。</p>
<p>大家在之前学过 <code>*</code> 操作符，知道它可以用于解引用，但是在裸指针 <code>*const T</code> 中，这里的 <code>*</code> 只是类型名称的一部分，并没有解引用的含义。</p>
<p>至此，我们已经学过三种类似指针的概念：引用、智能指针和裸指针。与前两者不同，裸指针：</p>
<ul>
<li>可以绕过 Rust 的借用规则，可以同时拥有一个数据的可变、不可变指针，甚至还能拥有多个可变的指针</li>
<li>并不能保证指向合法的内存</li>
<li>可以是 <code>null</code></li>
<li>没有实现任何自动的回收 (drop)</li>
</ul>
<p>总之，裸指针跟 C 指针是非常像的，使用它需要以牺牲安全性为前提，但我们获得了更好的性能，也可以跟其它语言或硬件打交道。</p>
<h4 id="基于引用创建裸指针"><a class="header" href="#基于引用创建裸指针">基于引用创建裸指针</a></h4>
<p>下面的代码<strong>基于值的引用</strong>同时创建了可变和不可变的裸指针：</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>let mut num = 5;
let r1 = &amp;num as *const i32;
let r2 = &amp;mut num as *mut i32;
<span class="boring">}
</span></code></pre></pre>
<p><code>as</code> 可以用于强制类型转换，在<a href="https://course.rs/basic/converse.html">之前章节</a>中有讲解。在这里，我们将引用 <code>&amp;num / &amp;mut num</code> 强转为相应的裸指针 <code>*const i32 / *mut i32</code>。</p>
<p>细心的同学可能会发现，在这段代码中并没有 <code>unsafe</code> 的身影，原因在于：<strong>创建裸指针是安全的行为，而解引用裸指针才是不安全的行为</strong> :</p>
<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
let mut num = 5;
let r1 = &amp;num as *const i32;
unsafe {
println!(&quot;r1 is: {}&quot;, *r1);
}
}
</code></pre></pre>
<h4 id="基于内存地址创建裸指针"><a class="header" href="#基于内存地址创建裸指针">基于内存地址创建裸指针</a></h4>
<p>在上面例子中，我们基于现有的引用来创建裸指针，这种行为是很安全的。但是接下来的方式就不安全了：</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>let address = 0x012345usize;
let r = address as *const i32;
<span class="boring">}
</span></code></pre></pre>
<p>这里基于一个内存地址来创建裸指针，可以想像，这种行为是相当危险的。试图使用任意的内存地址往往是一种未定义的行为(undefined behavior)，因为该内存地址有可能存在值，也有可能没有，就算有值，也大概率不是你需要的值。</p>
<p>同时编译器也有可能会优化这段代码，会造成没有任何内存访问发生，甚至程序还可能发生段错误(segmentation fault)。<strong>总之，你几乎没有好的理由像上面这样实现代码，虽然它是可行的</strong>。</p>
<p>如果真的要使用内存地址，也是类似下面的用法，先取地址，再使用，而不是凭空捏造一个地址：</p>
<pre><pre class="playground"><code class="language-rust edition2021">use std::{slice::from_raw_parts, str::from_utf8_unchecked};
// 获取字符串的内存地址和长度
fn get_memory_location() -&gt; (usize, usize) {
let string = &quot;Hello World!&quot;;
let pointer = string.as_ptr() as usize;
let length = string.len();
(pointer, length)
}
// 在指定的内存地址读取字符串
fn get_str_at_location(pointer: usize, length: usize) -&gt; &amp;'static str {
unsafe { from_utf8_unchecked(from_raw_parts(pointer as *const u8, length)) }
}
fn main() {
let (pointer, length) = get_memory_location();
let message = get_str_at_location(pointer, length);
println!(
&quot;The {} bytes at 0x{:X} stored: {}&quot;,
length, pointer, message
);
// 如果大家想知道为何处理裸指针需要 `unsafe`，可以试着反注释以下代码
// let message = get_str_at_location(1000, 10);
}
</code></pre></pre>
<p>以上代码同时还演示了访问非法内存地址会发生什么，大家可以试着去反注释这段代码试试。</p>
<h4 id="使用--解引用"><a class="header" href="#使用--解引用">使用 * 解引用</a></h4>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>let a = 1;
let b: *const i32 = &amp;a as *const i32;
let c: *const i32 = &amp;a;
unsafe {
println!(&quot;{}&quot;, *c);
}
<span class="boring">}
</span></code></pre></pre>
<p>使用 <code>*</code> 可以对裸指针进行解引用，由于该指针的内存安全性并没有任何保证，因此我们需要使用 <code>unsafe</code> 来包裹解引用的逻辑(切记，<code>unsafe</code> 语句块的范围一定要尽可能的小，具体原因在上一章节有讲)。</p>
<p>以上代码另一个值得注意的点就是：除了使用 <code>as</code> 来显式的转换，我们还使用了隐式的转换方式 <code>let c: *const i32 = &amp;a;</code>。在实际使用中，我们建议使用 <code>as</code> 来转换，因为这种显式的方式更有助于提醒用户：你在使用的指针是裸指针，需要小心。</p>
<h4 id="基于智能指针创建裸指针"><a class="header" href="#基于智能指针创建裸指针">基于智能指针创建裸指针</a></h4>
<p>还有一种创建裸指针的方式，那就是基于智能指针来创建:</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>let a: Box&lt;i32&gt; = Box::new(10);
// 需要先解引用a
let b: *const i32 = &amp;*a;
// 使用 into_raw 来创建
let c: *const i32 = Box::into_raw(a);
<span class="boring">}
</span></code></pre></pre>
<h4 id="小结"><a class="header" href="#小结">小结</a></h4>
<p>像之前代码演示的那样，使用裸指针可以让我们创建两个可变指针都指向同一个数据，如果使用安全的 Rust，你是无法做到这一点的，违背了借用规则，编译器会对我们进行无情的阻止。因此裸指针可以绕过借用规则，但是由此带来的数据竞争问题，就需要大家自己来处理了，总之，需要小心！</p>
<p>既然这么危险，为何还要使用裸指针？除了之前提到的性能等原因，还有一个重要用途就是跟 <code>C</code> 语言的代码进行交互( FFI )，在讲解 FFI 之前，先来看看如何调用 unsafe 函数或方法。</p>
<h2 id="调用-unsafe-函数或方法"><a class="header" href="#调用-unsafe-函数或方法">调用 unsafe 函数或方法</a></h2>
<p><code>unsafe</code> 函数从外表上来看跟普通函数并无区别，唯一的区别就是它需要使用 <code>unsafe fn</code> 来进行定义。这种定义方式是为了告诉调用者：当调用此函数时，你需要注意它的相关需求，因为 Rust 无法担保调用者在使用该函数时能满足它所需的一切需求。</p>
<p>强制调用者加上 <code>unsafe</code> 语句块，就可以让他清晰的认识到，正在调用一个不安全的函数，需要小心看看文档，看看函数有哪些特别的要求需要被满足。</p>
<pre><pre class="playground"><code class="language-rust edition2021">unsafe fn dangerous() {}
fn main() {
dangerous();
}
</code></pre></pre>
<p>如果试图像上面这样调用，编译器就会报错：</p>
<pre><code class="language-shell">error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
--&gt; src/main.rs:3:5
|
3 | dangerous();
| ^^^^^^^^^^^ call to unsafe function
</code></pre>
<p>按照报错提示，加上 <code>unsafe</code> 语句块后，就能顺利执行了:</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>unsafe {
dangerous();
}
<span class="boring">}
</span></code></pre></pre>
<p>道理很简单，但一定要牢记在心：<strong>使用 unsafe 声明的函数时，一定要看看相关的文档，确定自己没有遗漏什么</strong>。</p>
<p>还有，<code>unsafe</code> 无需俄罗斯套娃，在 <code>unsafe</code> 函数体中使用 <code>unsafe</code> 语句块是多余的行为。</p>
<h2 id="用安全抽象包裹-unsafe-代码"><a class="header" href="#用安全抽象包裹-unsafe-代码">用安全抽象包裹 unsafe 代码</a></h2>
<p>一个函数包含了 <code>unsafe</code> 代码不代表我们需要将整个函数都定义为 <code>unsafe fn</code>。事实上，在标准库中有大量的安全函数，它们内部都包含了 <code>unsafe</code> 代码块，下面我们一起来看看一个很好用的标准库函数：<code>split_at_mut</code>。</p>
<p>大家可以想象一下这个场景：需要将一个数组分成两个切片，且每一个切片都要求是可变的。类似需求在安全 Rust 中是很难实现的，因为要对同一个数组做两个可变借用：</p>
<pre><pre class="playground"><code class="language-rust edition2021">fn split_at_mut(slice: &amp;mut [i32], mid: usize) -&gt; (&amp;mut [i32], &amp;mut [i32]) {
let len = slice.len();
assert!(mid &lt;= len);
(&amp;mut slice[..mid], &amp;mut slice[mid..])
}
fn main() {
let mut v = vec![1, 2, 3, 4, 5, 6];
let r = &amp;mut v[..];
let (a, b) = split_at_mut(r, 3);
assert_eq!(a, &amp;mut [1, 2, 3]);
assert_eq!(b, &amp;mut [4, 5, 6]);
}
</code></pre></pre>
<p>上面代码一眼看过去就知道会报错，因为我们试图在自定义的 <code>split_at_mut</code> 函数中，可变借用 <code>slice</code> 两次：</p>
<pre><code class="language-shell">error[E0499]: cannot borrow `*slice` as mutable more than once at a time
--&gt; src/main.rs:6:30
|
1 | fn split_at_mut(slice: &amp;mut [i32], mid: usize) -&gt; (&amp;mut [i32], &amp;mut [i32]) {
| - let's call the lifetime of this reference `'1`
...
6 | (&amp;mut slice[..mid], &amp;mut slice[mid..])
| -------------------------^^^^^--------
| | | |
| | | second mutable borrow occurs here
| | first mutable borrow occurs here
| returning this value requires that `*slice` is borrowed for `'1`
</code></pre>
<p>对于 Rust 的借用检查器来说，它无法理解我们是分别借用了同一个切片的两个不同部分，但事实上，这种行为是没任何问题的，毕竟两个借用没有任何重叠之处。总之，不太聪明的 Rust 编译器阻碍了我们用这种简单且安全的方式去实现，那只能剑走偏锋，试试 <code>unsafe</code> 了。</p>
<pre><pre class="playground"><code class="language-rust edition2021">use std::slice;
fn split_at_mut(slice: &amp;mut [i32], mid: usize) -&gt; (&amp;mut [i32], &amp;mut [i32]) {
let len = slice.len();
let ptr = slice.as_mut_ptr();
assert!(mid &lt;= len);
unsafe {
(
slice::from_raw_parts_mut(ptr, mid),
slice::from_raw_parts_mut(ptr.add(mid), len - mid),
)
}
}
fn main() {
let mut v = vec![1, 2, 3, 4, 5, 6];
let r = &amp;mut v[..];
let (a, b) = split_at_mut(r, 3);
assert_eq!(a, &amp;mut [1, 2, 3]);
assert_eq!(b, &amp;mut [4, 5, 6]);
}
</code></pre></pre>
<p>相比安全实现，这段代码就显得没那么好理解了，甚至于我们还需要像 C 语言那样，通过指针地址的偏移去控制数组的分割。</p>
<ul>
<li><code>as_mut_ptr</code> 会返回指向 <code>slice</code> 首地址的裸指针 <code>*mut i32</code></li>
<li><code>slice::from_raw_parts_mut</code> 函数通过指针和长度来创建一个新的切片，简单来说，该切片的初始地址是 <code>ptr</code>，长度为 <code>mid</code></li>
<li><code>ptr.add(mid)</code> 可以获取第二个切片的初始地址，由于切片中的元素是 <code>i32</code> 类型，每个元素都占用了 4 个字节的内存大小，因此我们不能简单的用 <code>ptr + mid</code> 来作为初始地址，而应该使用 <code>ptr + 4 * mid</code>，但是这种使用方式并不安全，因此 <code>.add</code> 方法是最佳选择</li>
</ul>
<p>由于 <code>slice::from_raw_parts_mut</code> 使用裸指针作为参数，因此它是一个 <code>unsafe fn</code>，我们在使用它时，就必须用 <code>unsafe</code> 语句块进行包裹，类似的，<code>.add</code> 方法也是如此(还是那句话，不要将无关的代码包含在 <code>unsafe</code> 语句块中)。</p>
<p>部分同学可能会有疑问，那这段代码我们怎么保证 <code>unsafe</code> 中使用的裸指针 <code>ptr</code> 和 <code>ptr.add(mid)</code> 是合法的呢？秘诀就在于 <code>assert!(mid &lt;= len);</code> ，通过这个断言，我们保证了裸指针一定指向了 <code>slice</code> 切片中的某个元素，而不是一个莫名其妙的内存地址。</p>
<p>再回到我们的主题：<strong>虽然 split_at_mut 使用了 <code>unsafe</code>，但我们无需将其声明为 <code>unsafe fn</code></strong>，这种情况下就是使用安全的抽象包裹 <code>unsafe</code> 代码，这里的 <code>unsafe</code> 使用是非常安全的，因为我们从合法数据中创建了的合法指针。</p>
<p>与之对比，下面的代码就非常危险了:</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>use std::slice;
let address = 0x01234usize;
let r = address as *mut i32;
let slice: &amp;[i32] = unsafe { slice::from_raw_parts_mut(r, 10000) };
println!(&quot;{:?}&quot;,slice);
<span class="boring">}
</span></code></pre></pre>
<p>这段代码从一个任意的内存地址，创建了一个 10000 长度的 <code>i32</code> 切片，我们无法保证切片中的元素都是合法的 <code>i32</code> 值，这种访问就是一种未定义行为(UB = undefined behavior)。</p>
<pre><code class="language-shell">zsh: segmentation fault
</code></pre>
<p>不出所料，运行后看到了一个段错误。</p>
<h2 id="ffi"><a class="header" href="#ffi">FFI</a></h2>
<p><code>FFI</code>（Foreign Function Interface）可以用来与其它语言进行交互，但是并不是所有语言都这么称呼，例如 Java 称之为 <code>JNI（Java Native Interface）</code>。</p>
<p><code>FFI</code> 之所以存在是由于现实中很多代码库都是由不同语言编写的，如果我们需要使用某个库，但是它是由其它语言编写的，那么往往只有两个选择：</p>
<ul>
<li>对该库进行重写或者移植</li>
<li>使用 <code>FFI</code></li>
</ul>
<p>前者相当不错，但是在很多时候，并没有那么多时间去重写，因此 <code>FFI</code> 就成了最佳选择。回到 Rust 语言上，由于这门语言依然很年轻，一些生态是缺失的，我们在写一些不是那么大众的项目时，可能会同时遇到没有相应的 Rust 库可用的尴尬境况，此时通过 <code>FFI</code> 去调用 C 语言的库就成了相当棒的选择。</p>
<p>还有在将 C/C++ 的代码重构为 Rust 时，先将相关代码引入到 Rust 项目中，然后逐步重构，也是不错的(为什么用不错来形容？因为重构一个有一定规模的 C/C++ 项目远没有想象中美好，因此最好的选择还是对于新项目使用 Rust 实现，老项目。。就让它先运行着吧)。</p>
<p>当然，除了 <code>FFI</code> 还有一个办法可以解决跨语言调用的问题，那就是将其作为一个独立的服务，然后使用网络调用的方式去访问，HTTP，gRPC 都可以。</p>
<p>言归正传，之前我们提到 <code>unsafe</code> 的另一个重要目的就是对 <code>FFI</code> 提供支持，它的全称是 <code>Foreign Function Interface</code>，顾名思义，通过 <code>FFI</code> , 我们的 Rust 代码可以跟其它语言的外部代码进行交互。</p>
<p>下面的例子演示了如何调用 C 标准库中的 <code>abs</code> 函数：</p>
<pre><pre class="playground"><code class="language-rust edition2021">extern &quot;C&quot; {
fn abs(input: i32) -&gt; i32;
}
fn main() {
unsafe {
println!(&quot;Absolute value of -3 according to C: {}&quot;, abs(-3));
}
}
</code></pre></pre>
<p>C 语言的代码定义在了 <code>extern</code> 代码块中， 而 <code>extern</code> 必须使用 <code>unsafe</code> 才能进行进行调用，原因在于其它语言的代码并不会强制执行 Rust 的规则，因此 Rust 无法对这些代码进行检查，最终还是要靠开发者自己来保证代码的正确性和程序的安全性。</p>
<h4 id="abi"><a class="header" href="#abi">ABI</a></h4>
<p>在 <code>extern &quot;C&quot;</code> 代码块中，我们列出了想要调用的外部函数的签名。其中 <code>&quot;C&quot;</code> 定义了外部函数所使用的<strong>应用二进制接口</strong><code>ABI</code> (Application Binary Interface)：<code>ABI</code> 定义了如何在汇编层面来调用该函数。在所有 <code>ABI</code> 中，C 语言的是最常见的。</p>
<h4 id="在其它语言中调用-rust-函数"><a class="header" href="#在其它语言中调用-rust-函数">在其它语言中调用 Rust 函数</a></h4>
<p>在 Rust 中调用其它语言的函数是让 Rust 利用其他语言的生态，那反过来可以吗？其他语言可以利用 Rust 的生态不？答案是肯定的。</p>
<p>我们可以使用 <code>extern</code> 来创建一个接口，其它语言可以通过该接口来调用相关的 Rust 函数。但是此处的语法与之前有所不同，之前用的是语句块，而这里是在函数定义时加上 <code>extern</code> 关键字，当然，别忘了指定相应的 <code>ABI</code>：</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>#[no_mangle]
pub extern &quot;C&quot; fn call_from_c() {
println!(&quot;Just called a Rust function from C!&quot;);
}
<span class="boring">}
</span></code></pre></pre>
<p>上面的代码可以让 <code>call_from_c</code> 函数被 <code>C</code> 语言的代码调用，当然，前提是将其编译成一个共享库，然后链接到 C 语言中。</p>
<p>这里还有一个比较奇怪的注解 <code>#[no_mangle]</code>，它用于告诉 Rust 编译器：不要乱改函数的名称。 <code>Mangling</code> 的定义是：当 Rust 因为编译需要去修改函数的名称，例如为了让名称包含更多的信息，这样其它的编译部分就能从该名称获取相应的信息，这种修改会导致函数名变得相当不可读。</p>
<p>因此，为了让 Rust 函数能顺利被其它语言调用，我们必须要禁止掉该功能。</p>
<h2 id="访问或修改一个可变的静态变量"><a class="header" href="#访问或修改一个可变的静态变量">访问或修改一个可变的静态变量</a></h2>
<p>这部分我们在之前的<a href="https://course.rs/advance/global-variable.html#%E9%9D%99%E6%80%81%E5%8F%98%E9%87%8F">全局变量章节</a>中有过详细介绍，这里就不再赘述，大家可以前往此章节阅读。</p>
<h2 id="实现-unsafe-特征"><a class="header" href="#实现-unsafe-特征">实现 unsafe 特征</a></h2>
<p>说实话，<code>unsafe</code> 的特征确实不多见，如果大家还记得的话，我们在之前的 <a href="https://course.rs/advance/concurrency-with-threads/send-sync.html#%E4%B8%BA%E8%A3%B8%E6%8C%87%E9%92%88%E5%AE%9E%E7%8E%B0sync">Send 和 Sync</a> 章节中实现过 <code>unsafe</code> 特征 <code>Send</code>。</p>
<p>之所以会有 <code>unsafe</code> 的特征，是因为该特征至少有一个方法包含有编译器无法验证的内容。<code>unsafe</code> 特征的声明很简单：</p>
<pre><pre class="playground"><code class="language-rust edition2021">unsafe trait Foo {
// 方法列表
}
unsafe impl Foo for i32 {
// 实现相应的方法
}
fn main() {}
</code></pre></pre>
<p>通过 <code>unsafe impl</code> 的使用，我们告诉编译器：相应的正确性由我们自己来保证。</p>
<p>再回到刚提到的 <code>Send</code> 特征，若我们的类型中的所有字段都实现了 <code>Send</code> 特征，那该类型也会自动实现 <code>Send</code>。但是如果我们想要为某个类型手动实现 <code>Send</code> ，例如为裸指针，那么就必须使用 <code>unsafe</code>，相关的代码在之前的链接中也有，大家可以移步查看。</p>
<p>总之，<code>Send</code> 特征标记为 <code>unsafe</code> 是因为 Rust 无法验证我们的类型是否能在线程间安全的传递，因此就需要通过 <code>unsafe</code> 来告诉编译器，它无需操心，剩下的交给我们自己来处理。</p>
<h2 id="访问-union-中的字段"><a class="header" href="#访问-union-中的字段">访问 union 中的字段</a></h2>
<p>截止目前，我们还没有介绍过 <code>union</code> ，原因很简单，它主要用于跟 <code>C</code> 代码进行交互。</p>
<p>访问 <code>union</code> 的字段是不安全的，因为 Rust 无法保证当前存储在 <code>union</code> 实例中的数据类型。</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>#[repr(C)]
union MyUnion {
f1: u32,
f2: f32,
}
<span class="boring">}
</span></code></pre></pre>
<p>上从可以看出，<code>union</code> 的使用方式跟结构体确实很相似，但是前者的所有字段都共享同一个存储空间，意味着往 <code>union</code> 的某个字段写入值，会导致其它字段的值会被覆盖。</p>
<p>关于 <code>union</code> 的更多信息，可以在<a href="https://doc.rust-lang.org/reference/items/unions.html">这里查看</a>。</p>
<h2 id="一些实用工具库"><a class="header" href="#一些实用工具库">一些实用工具(库)</a></h2>
<p>由于 <code>unsafe</code> 和 <code>FFI</code> 在 Rust 的使用场景中是相当常见的(例如相对于 Go 的 <code>unsafe</code> 来说)，因此社区已经开发出了相当一部分实用的工具，可以改善相应的开发体验。</p>
<h4 id="rust-bindgen-和-cbindgen"><a class="header" href="#rust-bindgen-和-cbindgen">rust-bindgen 和 cbindgen</a></h4>
<p>对于 <code>FFI</code> 调用来说，保证接口的正确性是非常重要的，这两个库可以帮我们自动生成相应的接口，其中 <a href="https://github.com/rust-lang/rust-bindgen"><code>rust-bindgen</code></a> 用于在 Rust 中访问 C 代码，而 <a href="https://github.com/eqrion/cbindgen/"><code>cbindgen</code></a>则反之。</p>
<p>下面以 <code>rust-bindgen</code> 为例，来看看如何自动生成调用 C 的代码，首先下面是 C 代码:</p>
<pre><code class="language-c">typedef struct Doggo {
int many;
char wow;
} Doggo;
void eleven_out_of_ten_majestic_af(Doggo* pupper);
</code></pre>
<p>下面是自动生成的可以调用上面代码的 Rust 代码：</p>
<pre><pre class="playground"><code class="language-rust edition2021">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>/* automatically generated by rust-bindgen 0.99.9 */
#[repr(C)]
pub struct Doggo {
pub many: ::std::os::raw::c_int,
pub wow: ::std::os::raw::c_char,
}
extern &quot;C&quot; {
pub fn eleven_out_of_ten_majestic_af(pupper: *mut Doggo);
}
<span class="boring">}
</span></code></pre></pre>
<h4 id="cxx"><a class="header" href="#cxx">cxx</a></h4>
<p>如果需要跟 C++ 代码交互，非常推荐使用 <a href="https://github.com/dtolnay/cxx"><code>cxx</code></a>，它提供了双向的调用，最大的优点就是安全：是的，你无需通过 <code>unsafe</code> 来使用它！</p>
<h4 id="miri"><a class="header" href="#miri">Miri</a></h4>
<p><a href="https://github.com/rust-lang/miri"><code>miri</code></a> 可以生成 Rust 的中间层表示 MIR，对于编译器来说，我们的 Rust 代码首先会被编译为 MIR ，然后再提交给 LLVM 进行处理。</p>
<p>可以通过 <code>rustup component add miri</code> 来安装它，并通过 <code>cargo miri</code> 来使用，同时还可以使用 <code>cargo miri test</code> 来运行测试代码。</p>
<p><code>miri</code> 可以帮助我们检查常见的未定义行为(UB = Undefined Behavior)，以下列出了一部分:</p>
<ul>
<li>内存越界检查和内存释放后再使用(use-after-free)</li>
<li>使用未初始化的数据</li>
<li>数据竞争</li>
<li>内存对齐问题</li>
</ul>
<p>但是需要注意的是，它只能帮助识别被执行代码路径的风险，那些未被执行到的代码是没办法被识别的。</p>
<h4 id="clippy"><a class="header" href="#clippy">Clippy</a></h4>
<p>官方的 <a href="https://github.com/rust-lang/rust-clippy"><code>clippy</code></a> 检查器提供了有限的 <code>unsafe</code> 支持，虽然不多，但是至少有一定帮助。例如 <code>missing_safety_docs</code> 检查可以帮助我们检查哪些 <code>unsafe</code> 函数遗漏了文档。</p>
<p>需要注意的是： Rust 编译器并不会默认开启所有检查，大家可以调用 <code>rustc -W help</code> 来看看最新的信息。</p>
<h4 id="prusti"><a class="header" href="#prusti">Prusti</a></h4>
<p><a href="https://viperproject.github.io/prusti-dev/user-guide/"><code>prusti</code></a> 需要大家自己来构建一个证明，然后通过它证明代码中的不变量是正确被使用的，当你在安全代码中使用不安全的不变量时，就会非常有用。具体的使用文档见<a href="https://viperproject.github.io/prusti-dev/user-guide/">这里</a>。</p>
<h4 id="模糊测试fuzz-testing"><a class="header" href="#模糊测试fuzz-testing">模糊测试(fuzz testing)</a></h4>
<p>在 <a href="https://rust-fuzz.github.io/book/">Rust Fuzz Book</a> 中列出了一些 Rust 可以使用的模糊测试方法。</p>
<p>同时，我们还可以使用 <a href="https://github.com/jakubadamw/rutenspitz"><code>rutenspitz</code></a> 这个过程宏来测试有状态的代码，例如数据结构。</p>
<h2 id="总结"><a class="header" href="#总结">总结</a></h2>
<p>至此，<code>unsafe</code> 的五种兵器已介绍完毕，大家是否意犹未尽？我想说的是，就算意犹未尽，也没有其它兵器了。</p>
<p>就像上一章中所提到的，<code>unsafe</code> 只应该用于这五种场景，其它场景，你应该坚决的使用安全的代码，否则就会像 <code>actix-web</code> 的前作者一样，被很多人议论，甚至被喷。。。</p>
<p>总之，能不使用 <code>unsafe</code> 一定不要使用，就算使用也要控制好边界，让范围尽可能的小，就像本章的例子一样，只有真的需要 <code>unsafe</code> 的代码，才应该包含其中, 而不是将无关代码也纳入进来。</p>
<h2 id="进一步学习"><a class="header" href="#进一步学习">进一步学习</a></h2>
<ol>
<li><a href="https://blog.logrocket.com/unsafe-rust-how-and-when-not-to-use-it/">Unsafe Rust: How and when (not) to use it</a></li>
</ol>
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