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[options] ​

声明 CMake 缓存选项。每个选项自动生成两个条件，可直接用在条件键里。

toml
[options]
MYPROJECT_BUILD_TESTS = false
MYPROJECT_SPECIAL_OPTION = { value = true, help = "Docstring for this option." }
MYPROJECT_BUILD_EXAMPLES = "root"

三种写法 ​

写法含义
NAME = true / false简单布尔选项
NAME = { value = true, help = "..." }带 help 文本
NAME = "root"顶层项目才为 true；被 fetch-content / subdir 引入时 false

对应 CMake option() 缓存变量，configure 时用 -DMYPROJECT_BUILD_TESTS=ON 切换。

自动生成条件 ​

每个选项生成两个条件：

  1. 原名：MYPROJECT_BUILD_TESTS
  2. 归一化短横线（基于 [project].name）：MYPROJECT_BUILD_TESTS → build-tests
toml
[project]
name = "myproject"

[options]
MYPROJECT_BUILD_TESTS = false

[target.tests]
condition = "build-tests"               # 归一化条件
type = "executable"
sources = ["tests/main.cpp"]

实例：条件启用 ​

toml
[project]
name = "myproject"

[options]
MYPROJECT_BUILD_EXAMPLES = "root"       # 根项目默认开，被 fetch 时关

[target.ex_demo]
condition = "build-examples"
type = "executable"
sources = ["examples/demo.cpp"]

cmake -DMYPROJECT_BUILD_EXAMPLES=OFF 可手动关；作为依赖被引入时自动关。

注意事项 ​

  • 选项名惯例全大写 + 下划线；条件键里用归一化短横线更简洁
  • "root" 特值只在条件里起作用，选项值本身不是布尔
  • 选项名要与 [variables] 区分——options 生成缓存变量，variables 生成普通 set()

下一步 ​