CMake 构建实例：从简单到复杂实战项目
下面通过4个逐步升级的实际项目实例，展示 CMake 的完整构建流程、目录结构和CMakeLists.txt编写。所有实例都遵循现代 CMake 最佳实践（CMake 3.15+，target-centric 写法，源码外构建）。
实例1：单文件 Hello World（最简单入门）
目录结构
hello/ ├── CMakeLists.txt └── main.cppmain.cpp
#include<iostream>intmain(){std::cout<<"Hello, CMake World!"<<std::endl;return0;}CMakeLists.txt
cmake_minimum_required(VERSION 3.15) project(HelloWorld LANGUAGES CXX) add_executable(${PROJECT_NAME} main.cpp) target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_17)构建命令
mkdirbuild&&cdbuild cmake..-DCMAKE_BUILD_TYPE=Release cmake --build../HelloWorld实例2：多文件 + 头文件目录（典型小型项目）
目录结构
math_app/ ├── CMakeLists.txt ├── main.cpp ├── include/ │ └── math_utils.h └── src/ └── math_utils.cppmath_utils.h
#pragmaoncedoubleadd(doublea,doubleb);doublemultiply(doublea,doubleb);math_utils.cpp
#include"math_utils.h"doubleadd(doublea,doubleb){returna+b;}doublemultiply(doublea,doubleb){returna*b;}main.cpp
#include<iostream>#include"math_utils.h"intmain(){std::cout<<"3 + 5 = "<<add(3,5)<<std::endl;std::cout<<"4 * 7 = "<<multiply(4,7)<<std::endl;}CMakeLists.txt
cmake_minimum_required(VERSION 3.15) project(MathApp LANGUAGES CXX) add_executable(${PROJECT_NAME} main.cpp src/math_utils.cpp ) target_include_directories(${PROJECT_NAME} PRIVATE include) target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_17)构建同上
实例3：分离库 + 多目录（中型项目推荐结构）
目录结构
calculator/ ├── CMakeLists.txt # 根目录 ├── app/ │ ├── CMakeLists.txt │ └── main.cpp ├── lib/ │ ├── CMakeLists.txt │ ├── include/calculator/ │ │ └── core.h │ └── src/ │ └── core.cpp └── tests/ # （可选，后续加测试）lib/include/calculator/core.h
#pragmaoncenamespacecalc{doubleadd(doublea,doubleb);doublesubtract(doublea,doubleb);}lib/src/core.cpp
#include"calculator/core.h"namespacecalc{doubleadd(doublea,doubleb){returna+b;}doublesubtract(doublea,doubleb){returna-b;}}app/main.cpp
#include<iostream>#include"calculator/core.h"intmain(){std::cout<<"10 - 4 = "<<calc::subtract(10,4)<<std::endl;return0;}lib/CMakeLists.txt（库）
add_library(calc_core STATIC src/core.cpp ) target_include_directories(calc_core PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include ) target_compile_features(calc_core PUBLIC cxx_std_17)app/CMakeLists.txt（可执行）
add_executable(calculator_app main.cpp) target_link_libraries(calculator_app PRIVATE calc_core)根 CMakeLists.txt
cmake_minimum_required(VERSION 3.15) project(Calculator LANGUAGES CXX) add_subdirectory(lib) add_subdirectory(app)构建命令
mkdirbuild&&cdbuild cmake..-DCMAKE_BUILD_TYPE=Release cmake --build../app/calculator_app实例4：完整项目（带静态/动态库选项 + 安装规则 + 测试）
扩展实例3，添加：
- 可选生成共享库
- 安装规则（
make install） - 简单单元测试
根 CMakeLists.txt（增强版）
cmake_minimum_required(VERSION 3.15) project(Calculator LANGUAGES CXX) # 选项：是否构建共享库（默认静态） option(BUILD_SHARED_LIBS "Build shared libraries" OFF) add_subdirectory(lib) add_subdirectory(app) add_subdirectory(tests) # 可选 # 安装规则 install(TARGETS calculator_app DESTINATION bin ) install(TARGETS calc_core DESTINATION lib ) install(DIRECTORY lib/include/ DESTINATION include )tests/CMakeLists.txt（使用 CMake 自带测试）
find_package(GTest QUIET) if(GTest_FOUND) add_executable(calc_test test_core.cpp) target_link_libraries(calc_test PRIVATE calc_core GTest::gtest_main) add_test(NAME CalcTest COMMAND calc_test) else() message(WARNING "Google Test not found, skipping tests") endif()构建 + 安装 + 测试
mkdirbuild&&cdbuild cmake..-DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON cmake --build.ctest.# 运行测试（如果有 GTest）sudocmake --install.--prefix /usr/local# 安装到系统总结：推荐项目模板（直接复制使用）
myproject/ ├── CMakeLists.txt ├── cmake/ # 可选：自定义模块 ├── app/ │ ├── CMakeLists.txt │ └── main.cpp ├── lib/ │ ├── CMakeLists.txt │ ├── include/myproject/ │ └── src/ ├── tests/ │ └── CMakeLists.txt └── third_party/ # 第三方库（如 vcpkg/conan 管理）这些实例覆盖了从单文件到中大型项目的全部常见需求。你可以直接复制修改使用。
如果你想看特定场景的实例（如集成 Boost/Qt/OpenCV、交叉编译 Android/iOS、使用 vcpkg/Conan 包管理、生成 deb/rpm 包等），告诉我，我立刻给出完整可运行的例子！
