CMake 速查表 Cheat Sheet

常用 CMake 变量

变量名	说明
CMAKE_CXX_STANDARD	指定 C++ 标准版本，例如 17。
CMAKE_CXX_STANDARD_REQUIRED	强制要求使用指定的 C++ 标准版本，值为 ON 或 OFF。
CMAKE_BUILD_TYPE	设置构建类型，例如 Debug 或 Release。
CMAKE_CXX_FLAGS	为 C++ 编译器添加全局编译选项。
CMAKE_CXX_FLAGS_DEBUG	为 Debug 构建类型添加特定的编译选项。
CMAKE_CXX_FLAGS_RELEASE	为 Release 构建类型添加特定的编译选项。
CMAKE_SOURCE_DIR	顶层 CMakeLists.txt 所在的目录路径。
CMAKE_BINARY_DIR	CMake 生成的构建文件所在的目录路径。
PROJECT_SOURCE_DIR	当前项目的源代码目录路径。
PROJECT_BINARY_DIR	当前项目的构建文件目录路径。
CMAKE_CURRENT_SOURCE_DIR	当前处理的 CMakeLists.txt 所在的源代码目录路径。
CMAKE_CURRENT_BINARY_DIR	当前处理的 CMakeLists.txt 所生成的构建文件所在的目录路径。
CMAKE_INSTALL_PREFIX	安装目标文件的根目录。
CMAKE_MODULE_PATH	查找自定义 CMake 模块的路径列表。
CMAKE_PREFIX_PATH	查找库和包的前缀路径列表。
CMAKE_INCLUDE_PATH	查找头文件的附加路径。
CMAKE_LIBRARY_PATH	查找库文件的附加路径。
CMAKE_RUNTIME_OUTPUT_DIRECTORY	指定可执行文件的输出目录。
CMAKE_ARCHIVE_OUTPUT_DIRECTORY	指定静态库和归档文件的输出目录。
CMAKE_LIBRARY_OUTPUT_DIRECTORY	指定动态库的输出目录。
CMAKE_VERBOSE_MAKEFILE	是否生成详细的 Makefile，值为 ON 或 OFF。
CMAKE_EXPORT_COMPILE_COMMANDS	生成用于编译数据库的 compile_commands.json 文件，值为 ON 或 OFF。
CMAKE_CONFIGURATION_TYPES	设置多配置构建的配置类型列表，例如 Debug;Release;MinSizeRel;RelWithDebInfo。

命令备忘清单

生成项目构建系统

$ cmake [<options>] <path-to-source | path-to-existing-build>bash
$ cmake [<options>] -S <path-to-source> -B <path-to-build>

建立一个项目

$ cmake --build <dir> [<options>] [-- <build-tool-options>]

安装项目

$ cmake --install <dir> [<options>]

运行指定项目

cmake --build <dir> --target <project>

打开一个项目

$ cmake --open <dir>

运行脚本

$ cmake [-D <var>=<value>]... -P <cmake-script-file>

运行命令行工具

$ cmake -E <command> [<options>]

运行查找包工具

$ cmake --find-package [<options>]

运行工作流预设

$ cmake --workflow [<options>]

查看帮助

$ cmake --help[-<topic>]

最小CMakeLists.txt

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
project(example)
add_executable(a.out a.cpp b.cpp)

通配符源文件

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cpp")

project(example)
add_executable(a.out ${src})

设置CXXFLAGS

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cc")

project(example)
set(CMAKE_CXX_FLAGS "-Wall -Werror -O3")
add_executable(a.out ${src})

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cc")

project(example)
add_executable(a.out ${src})
target_compile_options(a.out PRIVATE -Werror)

带有构建类型的CXXFLAGS

# 通用
set(CMAKE_CXX_FLAGS "-Wall -Werror -O3")
# 调试
set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS} -g")
# 发布
set(CMAKE_C_FLAGS_RELEASE "${CMAKE_CXX_FLAGS} -O3 -pedantic")

构建调试/发布版本

$ cmake -DCMAKE_BUILD_TYPE=Release ../
$ cmake -DCMAKE_BUILD_TYPE=Debug ../

带有类型的构建

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
project(example)
add_executable(a.out a.cc)

if(CMAKE_BUILD_TYPE STREQUAL "Debug")
  target_compile_options(a.out PRIVATE -g -O0 -Wall)
else()
  target_compile_options(a.out PRIVATE -O3 -Wall -Werror)
endif()

现代CMake更倾向于使用生成器表达式来检查条件，而不是检查CMAKE_BUILD_TYPE。

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cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
project(example)
add_executable(a.out a.cc)
target_compile_options(a.out PRIVATE
  $<IF:$<CONFIG:Debug>, -g -O0 -Wall, -O3 -Wall -Werror>
)

版本配置文件

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cpp")

project(example VERSION 1.0)
configure_file(version.h.in version.h)

add_executable(a.out ${src})
target_include_directories(a.out PUBLIC "${PROJECT_BINARY_DIR}")

version.h.in

#pragma once

#define VERSION_MAJOR @example_VERSION_MAJOR@
#define VERSION_MINOR @example_VERSION_MINOR@

构建/链接静态库

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cpp")

project(example VERSION 1.0)
configure_file(version.h.in version.h)

add_executable(a.out ${src})
add_library(b b.cpp)
target_link_libraries(a.out PUBLIC b)
target_include_directories(a.out PUBLIC "${PROJECT_BINARY_DIR}")

构建/链接共享库

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cpp")

project(example VERSION 1.0)
configure_file(version.h.in version.h)

add_executable(a.out ${src})
add_library(b SHARED b.cpp)
target_link_libraries(a.out PUBLIC b)
target_include_directories(a.out PUBLIC "${PROJECT_BINARY_DIR}")

子目录

子目录 fib/

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cpp")
add_library(b SHARED b.cpp)
target_include_directories(b PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")

项目目录

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
file(GLOB src "*.cpp")

project(example VERSION 1.0)
configure_file(version.h.in version.h)

add_executable(a.out ${src})
add_subdirectory(fib)
target_link_libraries(a.out PUBLIC b)
target_include_directories(a.out PUBLIC
    "${PROJECT_BINARY_DIR}"
    "${PROJECT_BINARY_DIR/fib}"
)

PUBLIC & PRIVATE

• PUBLIC - 只影响当前目标，不影响依赖项
• INTERFACE - 仅影响依赖项

cmake_minimum_required(VERSION 3.10)

project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
find_package(Boost)

add_executable(a.out a.cpp)
add_library(b STATIC b.cpp b.h)

target_include_directories(a.out PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}")
target_include_directories(b PRIVATE "${Boost_INCLUDE_DIR}")
target_link_libraries(a.out INTERFACE b) # 链接b失败

生成器表达式

cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)
project(example)

set(target fib)
add_library(${target} src/fib.cc)
target_compile_options(${target} PRIVATE -Wall -Werror -Wextra)
target_include_directories(${target}
  PUBLIC
    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
    $<INSTALL_INTERFACE:include>
  PRIVATE
    ${CMAKE_CURRENT_SOURCE_DIR}/src
)

安装

cmake_minimum_required(VERSION 3.10)
project(a)
add_library(b_static STATIC b.cc)
add_library(b_shared SHARED b.cc)
add_executable(a a.cc b.cc)

include(GNUInstallDirs)
set(INSTALL_TARGETS a b_static b_shared)
install(TARGETS ${INSTALL_TARGETS}
  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)
install(FILES b.h DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})

配置时运行命令

execute_process(
    COMMAND git submodule update --init --recursive
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    RESULT_VARIABLE GIT_SUBMOD_RESULT
)

选项

# $ make -p build
# $ cd build
# $ cmake -DBUILD_TEST=ON ../

option(BUILD_TEST "Build test" OFF)
if (BUILD_TEST)
    message("Build tests.")
else()
    message("Ignore tests.")
endif()

为库创建别名

当CMakeLists.txt在命名空间Foo::中导出Foo时，还需要创建一个别名Foo::Foo。

add_library(Foo::Foo ALIAS Foo)

查找和使用外部包

find_package(Boost REQUIRED COMPONENTS filesystem system) if(Boost_FOUND) include_directories(${Boost_INCLUDE_DIRS}) target_link_libraries(MyExecutable ${Boost_LIBRARIES}) endif()

设置 CMake 选项

在项目中使用 option() 语句为用户提供可配置选项。

cmake_minimum_required(VERSION 3.10)
project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

# Define an option
option(BUILD_TESTS "Build the tests" OFF)

if(BUILD_TESTS)
  enable_testing()
  add_subdirectory(tests)
endif()

使用条件语句

根据条件编译不同代码或设置不同编译选项。

cmake_minimum_required(VERSION 3.10)
project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
endif()

自定义命令和目标

使用 add_custom_command 和 add_custom_target 添加自定义构建步骤。

cmake_minimum_required(VERSION 3.10)
project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

add_custom_command(
  OUTPUT ${CMAKE_BINARY_DIR}/generated_file.cpp
  COMMAND ${CMAKE_COMMAND} -E echo "Generating file"
  COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_BINARY_DIR}/generated_file.cpp
  DEPENDS some_other_target
)

add_custom_target(generate_file ALL DEPENDS ${CMAKE_BINARY_DIR}/generated_file.cpp)
add_executable(a.out main.cpp ${CMAKE_BINARY_DIR}/generated_file.cpp)

使用 FindPackage 和 CMake 模块

利用 find_package 和 CMake 自带模块查找并使用外部库。

cmake_minimum_required(VERSION 3.10)
project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

find_package(Boost REQUIRED COMPONENTS filesystem system)
if(Boost_FOUND)
  include_directories(${Boost_INCLUDE_DIRS})
  target_link_libraries(a.out ${Boost_LIBRARIES})
else()
  message(FATAL_ERROR "Boost not found")
endif()

导出目标

为使库可以被其他项目使用，使用 install 命令导出目标。

cmake_minimum_required(VERSION 3.10)
project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

add_library(foo SHARED foo.cpp)
install(TARGETS foo EXPORT fooConfig
  ARCHIVE DESTINATION lib
  LIBRARY DESTINATION lib
  RUNTIME DESTINATION bin
)

install(EXPORT fooConfig DESTINATION cmake)

使用 FetchContent 下载外部项目

使用 FetchContent 下载并构建外部项目。

cmake_minimum_required(VERSION 3.11)
project(example)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

include(FetchContent)

FetchContent_Declare(
  googletest
  GIT_REPOSITORY https://github.com/google/googletest.git
  GIT_TAG release-1.10.0
)

FetchContent_MakeAvailable(googletest)

enable_testing()
add_executable(test_example test.cpp)
target_link_libraries(test_example gtest gtest_main)
add_test(NAME example_test COMMAND test_example)