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CMake语法—选项（option）

CMake语法—选项（option）

1 选项

1.1 定义

 
1f371a30bd0002168f6007c3a01e6584.png

1.2 说明

  • variable 选项名
  • help_text 描述、解释、备注
  • value 选项初始化值（除ON而外全为OFF）

2 应用注意事项

2.1 代码结构

  • learn_cmake：为根目录

  • build：为CMake配置输出目录（在此例中即生成sln解决方案的地方）

  • CMakeLists.txt：CMake脚本

  • cmake_config.bat：执行CMake配置过程的脚本（双击直接运行）

     
      @echo off
      set currentDir=%~dp0
      set buildDir=%currentDir%
      set cmakeOutputDir=%currentDir%\build
      cmake -S %buildDir% -B %cmakeOutputDir% -G"Visual Studio 16 2019" -T v140 -A x64
      pause

2.2 注意事项

2.2.1 不初始化或赋为非ON的值，全部视为OFF

  1. 示例代码

     
      cmake_minimum_required(VERSION 3.18)
       
      # 设置工程名称
      set(PROJECT_NAME KAIZEN)
       
      # 设置工程版本号
      set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
       
      # 工程定义
      project(${PROJECT_NAME}
      LANGUAGES CXX C
      VERSION ${PROJECT_VERSION}
      )
       
      # 打印开始日志
      message(STATUS "\n########## BEGIN_TEST_OPTION")
       
      ## 示例1：不赋值
      option(${PROJECT_NAME}_BUILD_TEST "构建测试模块")
       
      if (DEFINED ${PROJECT_NAME}_BUILD_TEST)
      message(STATUS "defined KAIZEN_BUILD_TEST")
      else()
      message(STATUS "not defined KAIZEN_BUILD_TEST")
      endif()
       
      if (${PROJECT_NAME}_BUILD_TEST)
      message(STATUS "KAIZEN_BUILD_TEST is ON")
      else()
      message(STATUS "KAIZEN_BUILD_TEST is OFF")
      endif()
      message(STATUS "\n")
       
      ## 示例2：赋值为非ON、非OFF值
      option(${PROJECT_NAME}_BUILD_EXAMPLE "构建示例模块" AAA)
       
      if (DEFINED ${PROJECT_NAME}_BUILD_EXAMPLE)
      message(STATUS "defined KAIZEN_BUILD_EXAMPLE")
      else()
      message(STATUS "not defined KAIZEN_BUILD_EXAMPLE")
      endif()
       
      if (${PROJECT_NAME}_BUILD_EXAMPLE)
      message(STATUS "KAIZEN_BUILD_EXAMPLE_1 is ON")
      else()
      message(STATUS "KAIZEN_BUILD_EXAMPLE_1 is OFF")
      endif()
       
      if (${${PROJECT_NAME}_BUILD_TYPE})
      message(STATUS "KAIZEN_BUILD_EXAMPLE_2 is ON")
      else()
      message(STATUS "KAIZEN_BUILD_EXAMPLE_2 is OFF")
      endif()
      message(STATUS "\n")
       
      ## 示例3：赋值为ON
      option(${PROJECT_NAME}_BUILD_GUI "构建视图模块" ON)
       
      if (DEFINED ${PROJECT_NAME}_BUILD_GUI)
      message(STATUS "defined KAIZEN_BUILD_GUI")
      else()
      message(STATUS "not defined KAIZEN_BUILD_GUI")
      endif()
       
      if (${PROJECT_NAME}_BUILD_GUI)
      message(STATUS "KAIZEN_BUILD_GUI is ON")
      else()
      message(STATUS "KAIZEN_BUILD_GUI is OFF")
      endif()
       
      # 打印结束日志
      message(STATUS "########## END_TEST_OPTION\n")

  2. 运行结果

     
      -- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
      -- The CXX compiler identification is MSVC 19.0.24245.0
      -- The C compiler identification is MSVC 19.0.24245.0
      -- Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Detecting C compiler ABI info
      -- Detecting C compiler ABI info - done
      -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
      -- Detecting C compile features
      -- Detecting C compile features - done
      --
      ########## BEGIN_TEST_OPTION
      -- defined KAIZEN_BUILD_TEST
      -- KAIZEN_BUILD_TEST is OFF
      --
       
      -- defined KAIZEN_BUILD_EXAMPLE
      -- KAIZEN_BUILD_EXAMPLE_1 is OFF
      -- KAIZEN_BUILD_EXAMPLE_2 is OFF
      --
       
      -- defined KAIZEN_BUILD_GUI
      -- KAIZEN_BUILD_GUI is ON
      -- ########## END_TEST_OPTION
       
      -- Configuring done
      -- Generating done
      -- Build files have been written to: F:/learn_cmake/build
      请按任意键继续. . .

2.2.2 在定义语句执行后才有效；在定义之前均视为未定义（除过在CMake命令中通过-D预定义）

  1. 示例代码

     
      cmake_minimum_required(VERSION 3.18)
       
      # 设置工程名称
      set(PROJECT_NAME KAIZEN)
       
      # 设置工程版本号
      set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
       
      # 工程定义
      project(${PROJECT_NAME}
      LANGUAGES CXX C
      VERSION ${PROJECT_VERSION}
      )
       
      # 打印开始日志
      message(STATUS "\n########## BEGIN_TEST_OPTION")
       
      ## 定义之前是看不到的
      if (DEFINED ${PROJECT_NAME}_BUILD_TEST)
      message(STATUS "defined KAIZEN_BUILD_TEST")
      else()
      message(STATUS "not defined KAIZEN_BUILD_TEST")
      endif()
       
      ## 定义语句
      option(${PROJECT_NAME}_BUILD_TEST "构建测试模块" ON)
       
      ## 定义后才可以看到
      if (DEFINED ${PROJECT_NAME}_BUILD_TEST)
      message(STATUS "defined KAIZEN_BUILD_TEST")
      else()
      message(STATUS "not defined KAIZEN_BUILD_TEST")
      endif()
       
      ## 定义后再应用
      if (${PROJECT_NAME}_BUILD_TEST)
      message(STATUS "KAIZEN_BUILD_TEST is ON")
      else()
      message(STATUS "KAIZEN_BUILD_TEST is OFF")
      endif()
       
      # 打印结束日志
      message(STATUS "########## END_TEST_OPTION\n")
       

  2. 运行结果

     
      -- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
      -- The CXX compiler identification is MSVC 19.0.24245.0
      -- The C compiler identification is MSVC 19.0.24245.0
      -- Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Detecting C compiler ABI info
      -- Detecting C compiler ABI info - done
      -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
      -- Detecting C compile features
      -- Detecting C compile features - done
      --
      ########## BEGIN_TEST_OPTION
      -- not defined KAIZEN_BUILD_TEST
      -- defined KAIZEN_BUILD_TEST
      -- KAIZEN_BUILD_TEST is ON
      -- ########## END_TEST_OPTION
       
      -- Configuring done
      -- Generating done
      -- Build files have been written to: F:/learn_cmake/build
      请按任意键继续. . .

2.2.3 已定义option选项会存储在CMakeCache.txt中。等价于缓存变量作用。

运行2.2.1中的示例代码，然后可以查看build目录下的CMakeCache.txt文件。如下图：

2.2.4 如果出现同名的变量（普通或缓存变量），则option会被忽略

  1. 示例代码

     
      cmake_minimum_required(VERSION 3.18)
       
      # 设置工程名称
      set(PROJECT_NAME KAIZEN)
       
      # 设置工程版本号
      set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
       
      # 工程定义
      project(${PROJECT_NAME}
      LANGUAGES CXX C
      VERSION ${PROJECT_VERSION}
      )
       
      # 打印开始日志
      message(STATUS "\n########## BEGIN_TEST_OPTION")
       
      ## 1.1先定义普通变量
      set(${PROJECT_NAME}_BUILD_TEST "构建测试模块")
       
      if (DEFINED ${PROJECT_NAME}_BUILD_TEST)
      message(STATUS "defined KAIZEN_BUILD_TEST")
      else()
      message(STATUS "not defined KAIZEN_BUILD_TEST")
      endif()
       
      message(STATUS "KAIZEN_BUILD_TEST_1: ${${PROJECT_NAME}_BUILD_TEST}\n")
       
      ## 1.2再定义同名option选项
      option(${PROJECT_NAME}_BUILD_TEST "构建测试模块" ON)
       
      message(STATUS "KAIZEN_BUILD_TEST_2: ${${PROJECT_NAME}_BUILD_TEST}\n")
       
      ### 2.1先定义option选项
      option(${PROJECT_NAME}_BUILD_EXAMPLE "构建示例模块" OFF)
       
      if (DEFINED ${PROJECT_NAME}_BUILD_EXAMPLE)
      message(STATUS "defined KAIZEN_BUILD_EXAMPLE")
      else()
      message(STATUS "not defined KAIZEN_BUILD_EXAMPLE")
      endif()
       
      message(STATUS "KAIZEN_BUILD_EXAMPLE_1: ${KAIZEN_BUILD_EXAMPLE}")
       
      ### 2.2再定义普通同名变量
      set(${PROJECT_NAME}_BUILD_EXAMPLE "构建示例模块")
       
      message(STATUS "KAIZEN_BUILD_EXAMPLE_2: ${KAIZEN_BUILD_EXAMPLE}")
       
      # 打印结束日志
      message(STATUS "########## END_TEST_OPTION\n")

  2. 运行结果

     
      -- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
      -- The CXX compiler identification is MSVC 19.0.24245.0
      -- The C compiler identification is MSVC 19.0.24245.0
      -- Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Detecting C compiler ABI info
      -- Detecting C compiler ABI info - done
      -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
      -- Detecting C compile features
      -- Detecting C compile features - done
      --
      ########## BEGIN_TEST_OPTION
      -- defined KAIZEN_BUILD_TEST
      -- KAIZEN_BUILD_TEST_1: 构建测试模块
       
      -- KAIZEN_BUILD_TEST_2: 构建测试模块
       
      -- defined KAIZEN_BUILD_EXAMPLE
      -- KAIZEN_BUILD_EXAMPLE_1: OFF
      -- KAIZEN_BUILD_EXAMPLE_2: 构建示例模块
      -- ########## END_TEST_OPTION
       
      -- Configuring done
      -- Generating done
      -- Build files have been written to: F:/learn_cmake/build
      请按任意键继续. . .

2.2.5 CMake命令中通过-D预设同名变量，则option也会被忽略（其本质与2.2.4相同）

  1. 示例代码

     
      cmake_minimum_required(VERSION 3.18)
       
      # 设置工程名称
      set(PROJECT_NAME KAIZEN)
       
      # 设置工程版本号
      set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
       
      # 工程定义
      project(${ PROJECT_NAME }
      LANGUAGES CXX C
      VERSION ${ PROJECT_VERSION }
      )
       
      # 打印开始日志
      message(STATUS "\n########## BEGIN_TEST_OPTION")
       
      if (DEFINED ${ PROJECT_NAME }_BUILD_EXAMPLE)
      message(STATUS "defined KAIZEN_BUILD_EXAMPLE")
      else()
      message(STATUS "not defined KAIZEN_BUILD_EXAMPLE")
      endif()
       
      ## 定义option选项
      option(${ PROJECT_NAME }_BUILD_EXAMPLE "构建示例模块" OFF)
       
      message(STATUS "KAIZEN_BUILD_EXAMPLE: ${KAIZEN_BUILD_EXAMPLE}")
       
      # 打印结束日志
      message(STATUS "########## END_TEST_OPTION\n")

  2. cmake_config.bat

     
      @echo off
      set currentDir=%~dp0
      set buildDir=%currentDir%
      set cmakeOutputDir=%currentDir%\build
      cmake -S %buildDir% -B %cmakeOutputDir% -G"Visual Studio 16 2019" -T v140 -A x64 -DKAIZEN_BUILD_EXAMPLE=ON
      pause

  3. 运行结果

     
      --Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
      --The CXX compiler identification is MSVC 19.0.24245.0
      --The C compiler identification is MSVC 19.0.24245.0
      --Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler : C: / Program Files(x86) / Microsoft Visual Studio 14.0 / VC / bin / amd64 / cl.exe - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Detecting C compiler ABI info
      -- Detecting C compiler ABI info - done
      -- Check for working C compiler : C: / Program Files(x86) / Microsoft Visual Studio 14.0 / VC / bin / amd64 / cl.exe - skipped
      -- Detecting C compile features
      -- Detecting C compile features - done
      --
      ########## BEGIN_TEST_OPTION
      -- defined KAIZEN_BUILD_EXAMPLE
      -- KAIZEN_BUILD_EXAMPLE: ON
      -- ########## END_TEST_OPTION
       
      -- Configuring done
      -- Generating done
      -- Build files have been written to : F: / learn_cmake / build
      请按任意键继续. . .

2.2.6 修改option选项值（建议通过缓存变量方式修改）

  1. 示例代码

     
      cmake_minimum_required(VERSION 3.18)
       
      # 设置工程名称
      set(PROJECT_NAME KAIZEN)
       
      # 设置工程版本号
      set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
       
      # 工程定义
      project(${ PROJECT_NAME }
      LANGUAGES CXX C
      VERSION ${ PROJECT_VERSION }
      )
       
      # 打印开始日志
      message(STATUS "\n########## BEGIN_TEST_OPTION")
       
      if (DEFINED ${ PROJECT_NAME }_BUILD_EXAMPLE)
      message(STATUS "defined KAIZEN_BUILD_EXAMPLE")
      else()
      message(STATUS "not defined KAIZEN_BUILD_EXAMPLE")
      endif()
       
      ## 定义option选项
      option(${ PROJECT_NAME }_BUILD_EXAMPLE "构建示例模块" OFF)
       
      message(STATUS "KAIZEN_BUILD_EXAMPLE_1: ${KAIZEN_BUILD_EXAMPLE}")
       
      ## 方式一：修改option选项值（无效方式，请忽略）
      option(${ PROJECT_NAME }_BUILD_EXAMPLE "构建示例模块" ON)
       
      message(STATUS "KAIZEN_BUILD_EXAMPLE_2: ${KAIZEN_BUILD_EXAMPLE}")
       
      ## 方式二：通过cache变量方式修改（正确方式，力推荐）
      set(${ PROJECT_NAME }_BUILD_EXAMPLE ON CACHE BOOL "构建示例模块" FORCE)
       
      message(STATUS "KAIZEN_BUILD_EXAMPLE_3: ${KAIZEN_BUILD_EXAMPLE}")
       
      # 打印结束日志
      message(STATUS "########## END_TEST_OPTION\n")

  2. 运行结果

     
      --Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
      --The CXX compiler identification is MSVC 19.0.24245.0
      --The C compiler identification is MSVC 19.0.24245.0
      --Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler : C: / Program Files(x86) / Microsoft Visual Studio 14.0 / VC / bin / amd64 / cl.exe - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Detecting C compiler ABI info
      -- Detecting C compiler ABI info - done
      -- Check for working C compiler : C: / Program Files(x86) / Microsoft Visual Studio 14.0 / VC / bin / amd64 / cl.exe - skipped
      -- Detecting C compile features
      -- Detecting C compile features - done
      --
      ########## BEGIN_TEST_OPTION
      -- not defined KAIZEN_BUILD_EXAMPLE
      -- KAIZEN_BUILD_EXAMPLE_1: OFF
      -- KAIZEN_BUILD_EXAMPLE_2 : OFF
      -- KAIZEN_BUILD_EXAMPLE_3 : ON
      -- ########## END_TEST_OPTION
       
      -- Configuring done
      -- Generating done
      -- Build files have been written to : F: / learn_cmake / build
      请按任意键继续. . .

    INI 复制 全屏

    当然，也可以通过定义同名普通变量方式进行修改。

    但是，通过普通变量方式修改后，CMakeCache.txt中的值仍然为旧值。感兴趣可自行验证。

    option选项本质与缓存变量相同，即会存储在CMakeCache.txt中。因此修改其值也推荐使用缓存变量的方式，这样会直接修改CMakeCache.txt中的存储值，更彻底、更本质、更安全。

posted on 2023-02-01 10:26  DoubleLi  阅读(732)  评论(0)    收藏  举报