# 第2章 检测环境

本章的主要内容有：

* 检测操作系统
* 处理与平台相关的源码
* 处理与编译器相关的源码
* 检测处理器体系结构
* 检测处理器指令集
* 为Eigen库使能向量化

尽管CMake跨平台，但有时源代码并不是完全可移植(例如：当使用依赖于供应商的扩展时)，我们努力使源代码能够跨平台、操作系统和编译器。这个过程中会发现，有必要根据平台不同的方式配置和/或构建代码。这对于历史代码或交叉编译尤其重要，我们将在第13章中讨论这个主题。了解处理器指令集也有助于优化特定目标平台的性能。本章会介绍，检测环境的方法，并给出建议。


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