CMake语法—选项(option)
1 选项
1.1 定义
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
-
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")
-
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)
-
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")
-
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
-
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: ${KAIZEN_BUILD_EXAMPLE}")
# 打印结束日志
message(STATUS "########## END_TEST_OPTION\n")
-
运行结果
-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
-- The CXX compiler identification is MSVC 19.0.24245.0
-- The C compiler identification is MSVC 19.0.24245.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
--
########## BEGIN_TEST_OPTION
-- defined KAIZEN_BUILD_TEST
-- KAIZEN_BUILD_TEST_1: 构建测试模块
-- KAIZEN_BUILD_TEST_2: 构建测试模块
-- defined KAIZEN_BUILD_EXAMPLE
-- KAIZEN_BUILD_EXAMPLE_1: OFF
-- KAIZEN_BUILD_EXAMPLE_2: 构建示例模块
-- ########## END_TEST_OPTION
-- Configuring done
-- Generating done
-- Build files have been written to: F:/learn_cmake/build
请按任意键继续. . .
2.2.5 CMake命令中通过-D预设同名变量,则option也会被忽略(其本质与2.2.4相同)
-
示例代码
cmake_minimum_required(VERSION 3.18)
# 设置工程名称
set(PROJECT_NAME KAIZEN)
# 设置工程版本号
set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
# 工程定义
project(${ 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: ${KAIZEN_BUILD_EXAMPLE}")
# 打印结束日志
message(STATUS "########## END_TEST_OPTION\n")
-
cmake_config.bat
@echo off
set currentDir=%~dp0
set buildDir=%currentDir%
set cmakeOutputDir=%currentDir%\build
cmake -S %buildDir% -B %cmakeOutputDir% -G"Visual Studio 16 2019" -T v140 -A x64 -DKAIZEN_BUILD_EXAMPLE=ON
pause
-
运行结果
--Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
--The CXX compiler identification is MSVC 19.0.24245.0
--The C compiler identification is MSVC 19.0.24245.0
--Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler : C: / Program Files(x86) / Microsoft Visual Studio 14.0 / VC / bin / amd64 / cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler : C: / Program Files(x86) / Microsoft Visual Studio 14.0 / VC / bin / amd64 / cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
--
########## BEGIN_TEST_OPTION
-- defined KAIZEN_BUILD_EXAMPLE
-- KAIZEN_BUILD_EXAMPLE: ON
-- ########## END_TEST_OPTION
-- Configuring done
-- Generating done
-- Build files have been written to : F: / learn_cmake / build
请按任意键继续. . .
2.2.6 修改option选项值(建议通过缓存变量方式修改)
-
示例代码
cmake_minimum_required(VERSION 3.18)
# 设置工程名称
set(PROJECT_NAME KAIZEN)
# 设置工程版本号
set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
# 工程定义
project(${ 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")
-
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。