CMakeLists.txt 是通用的c++项目管理文件，
在不同的设备中，环境变量，编译器等都可能不同，
将这些设置都交给CMakeLists.txt , 并不是一个好办法。
为了降低CMakeLists.txt的臃肿程度，简化其判断，
可以针对不同设备，配置不同的CMakePresets.json.
使得项目可以在不同的设备上运行、测试。
一个由visual studio 2022 自动生成的CMakePresets.json，稍稍修改了一下。
{ "version": 3, "configurePresets": [ { "name": "windows-base", "hidden": true, "generator": "Ninja", "binaryDir": "${sourceDir}/out/build/${presetName}", "installDir": "${sourceDir}/out/install/${presetName}", "cacheVariables": { "CMAKE_C_COMPILER": "cl.exe", "CMAKE_CXX_COMPILER": "cl.exe" }, "environment": { "MY_ENVIRONMENT_VARIABLE": "Test" }, "condition": { "type": "equals", "lhs": "${hostSystemName}", "rhs": "Windows" } }, { "name": "x64-debug", "displayName": "x64 Debug", "inherits": "windows-base", "architecture": { "value": "x64", "strategy": "external" }, "cacheVariables": { "CMAKE_BUILD_TYPE": "Debug" } }, { "name": "x64-release", "displayName": "x64 Release", "inherits": "x64-debug", "cacheVariables": { "CMAKE_BUILD_TYPE": "Release" } }, { "name": "x86-debug", "displayName": "x86 Debug", "inherits": "windows-base", "architecture": { "value": "x86", "strategy": "external" }, "cacheVariables": { "CMAKE_BUILD_TYPE": "Debug" } }, { "name": "x86-release", "displayName": "x86 Release", "inherits": "x86-debug", "cacheVariables": { "CMAKE_BUILD_TYPE": "Release" } }, { "name": "linux-debug", "displayName": "Linux Debug", "generator": "Ninja", "binaryDir": "${sourceDir}/out/build/${presetName}", "installDir": "${sourceDir}/out/install/${presetName}", "cacheVariables": { "CMAKE_BUILD_TYPE": "Debug" }, "condition": { "type": "equals", "lhs": "${hostSystemName}", "rhs": "Linux" }, "vendor": { "microsoft.com/VisualStudioRemoteSettings/CMake/1.0": { "sourceDir": "$env{HOME}/.vs/$ms{projectDirName}" } } }, { "name": "macos-debug", "displayName": "macOS Debug", "generator": "Ninja", "binaryDir": "${sourceDir}/out/build/${presetName}", "installDir": "${sourceDir}/out/install/${presetName}", "cacheVariables": { "CMAKE_BUILD_TYPE": "Debug" }, "condition": { "type": "equals", "lhs": "${hostSystemName}", "rhs": "Darwin" }, "vendor": { "microsoft.com/VisualStudioRemoteSettings/CMake/1.0": { "sourceDir": "$env{HOME}/.vs/$ms{projectDirName}" } } } ] }
configurePresets 是一个 json 字段 []。
里面包含多个 设置， 这些设置有属性：name, hidden, generator,binaryDir, installDir .... 等组成。
后面的设置可以继承前面的设置。Visual Studio IDE根据选择的编译模式，自动从这里找到对应的配置名。
其中字段：cacheVariables 中的字段可以在 cmakelists中使用。
也可以像下面方法定义：
"cacheVariables": { "FIRST_CACHE_VARIABLE": { "type": "BOOL", "value": "OFF" }, "SECOND_CACHE_VARIABLE": "ON" },
environment 可以定义环境变量，上文例子中的引用方法：
$ENV{MY_ENVIRONMENT_VARIABLE}
除了这个配置，还可以配置：buildPresets, testPresets
"buildPresets": [ { "name": "default", "configurePreset": "default" } ], "testPresets": [ { "name": "default", "configurePreset": "default", "output": {"outputOnFailure": true}, "execution": {"noTestsAction": "error", "stopOnFailure": true} } ],
也可以包含其他json配置。
"include": [ "otherThings.json", "moreThings.json" ],