注：本人的临时记录，没什么参看价值，可移步https://cmake.org/cmake/help/v3.21/guide/tutorial/index.html

1. 概述

用CMake构建一个简单的项目，项目由一个exe以及一个dll组成，项目目录结构如上图，build_MyHello是编译生成的目录。项目包含ALL_BUILD,RUN_TEST,INSTALL,PACKAGE，如下图：

2. 详细步骤

1. MyHello/CMakeLists.txt
   add_subdirectory：将src目录加入编译，CMake会去src目录下找CMakeLists.txt。我在MyHello/src/CMakeLists.txt中使用了add_executable来编译一个exe。当让也可以直接在以下CMakeLists.txt中直接写add_executable，只是处理好路径即可，但在子目录中各自管理自己的CMakeLists.txt会更清晰些。

   cmake_minimum_required(VERSION 3.21)
   PROJECT(Hello VERSION 2.0)# 测试打印信息功能
   MESSAGE(STATUS "hello, this is cmake message")
   MESSAGE(STATUS ${PROJECT_BINARY_DIR})
   MESSAGE(STATUS ${Hello_VERSION_MAJOR})# 将src目录加入到编译中
   add_subdirectory(src)# 加入测试
   enable_testing()
   add_test(NAME Runs COMMAND MyHelloExe )
   add_test(NAME Usage COMMAND MyHelloExe )# 加入打包功能
   include(InstallRequiredSystemLibraries)
   set(CPACK_PACKAGE_VERSION_MAJOR "${Hello_VERSION_MAJOR}")
   set(CPACK_PACKAGE_VERSION_MINOR "${Hello_VERSION_MINOR}")
   include(CPack)

2. MyHello/src/CMakeLists.txt

   # 打印信息
   MESSAGE( STATUS ${PROJECT_SOURCE_DIR} )# set(CMAKE_CXX_STANDARD 11)
   # set(CMAKE_CXX_STANDARD_REQUIRED True)# 设置选项
   option(USE_MYMATH "Use my maths" ON)if( USE_MYMATH )# 将Maths文件夹加入编译add_subdirectory(Maths)list(APPEND EXTRA_LIBS MyMath)list(APPEND EXTRA_INCLUDES ${PROJECT_SOURCE_DIR}/Maths)
   endif()# 生成一个exe
   add_executable(MyHelloExe main.cpp)# 生成my_header.h文件，my_header.h.out中宏会被替换
   configure_file(my_header.h.out my_header.h)# 依赖的lib， target_link_directories可用来增加库目录
   target_link_libraries(MyHelloExe PUBLIC ${EXTRA_LIBS})# 头文件包含目录
   target_include_directories(MyHelloExe PUBLIC ${PROJECT_BINARY_DIR}/src ${EXTRA_INCLUDES} )# 测试加入预编译宏
   target_compile_definitions(MyHelloExe PRIVATE "HAVE_LOG" "HAVE_EXP")# 安装
   install(TARGETS MyHelloExe DESTINATION bin)
   install(FILES "${PROJECT_BINARY_DIR}/src/my_header.h" DESTINATION include )

3. MyHello/src/main.cpp

   #include <iostream>
   #include "my_header.h"int main(int argc, char** argv)
   {std::cout << "hello world" << std::endl;std::cout << "Version Main is " << Hello_VERSION_MAJOR << std::endl;std::cout << "Version Minor is " << Hello_VERSION_MINOR << std::endl;#ifdef USE_MYMATHstd::cout << "use my math" << std::endl;
   #endifreturn 0;
   }

4. MyHello/src/my_header.h.out
   一般会命名成my_header.h.in

   #define Hello_VERSION_MAJOR @Hello_VERSION_MAJOR@  //CMake的内置变量：<PROJECT-NAME>_VERSION_MAJOR
   #define Hello_VERSION_MINOR @Hello_VERSION_MINOR@  //CMake的内置变量：<PROJECT-NAME>_VERSION_MINOR
   #cmakedefine USE_MYMATH
   

5. MyHello/src/Maths/CMakeLists.txt

   # 打印信息
   message(STATUS "add Maths library")# 编译生成dll，不依赖其他库
   add_library(MyMath SHARED mysqrt.cpp)# 安装
   install(TARGETS MyMath LIBRARY DESTINATION lib)
   install(TARGETS MyMath RUNTIME DESTINATION bin)
   install(FILES mysqrt.h DESTINATION include)
   

6. MyHello/src/Maths/mysqrt.h
   测试用，无内容

7. MyHello/src/Maths/mysqrt.cpp

   #include "mysqrt.h"
   

3. 参看

https://cmake.org/cmake/help/v3.21/guide/tutorial/index.html