${CMAKE_MODULE_PATH}) "${CMAKE_CURRENT_LIST_DIR}/cmake/modules" include(cmake/cppCon20Find.cmake) find_package(Catch2) include(GNUInstallDir) if(Catch2_FOUND) enable_testing() endif() include(cmake/Functions

set(key val PARENT_SCOPE) 才能修改到外面的变量。 ## 第二章：第三方库 / 依赖项配置 用 find_package 寻找系统中安装的第三方库并链接他们 ## find_package 命令 - 常用参数列表一览： • find_package( [version] [EXACT] [QUIET] [CONFIG] [MODULE] • [REQUIRED] [[COMPONENTS] [components...]] • [OPTIONAL_COMPONENTS components...] ## find_package 命令用法举例 • find package(OpenCV) - 查找名为 OpenCV 的包，找不到不报错，事后可以通过 $ \{OpenCV\_FOUND\} $ 查询是否找到。 组件。 ## find_package 说是找“包”，到底是在找什么？ • find_package(OpenCV) 实际上是在找一个名为 OpenCVConfig.cmake 的文件。 - 注：出于历史兼容性考虑，除了 OpenCVConfig.cmake 以外 OpenCV-config.cmake 这个文件名也会被 CMake 识别到。 • 同理，find_package(Qt5) 则是会去找名为

[Image](/uploads/documents/b/b/d/6/bbd66be3b8ad8501e66f11434b3a5cf1/p3_1.jpg) ## 现代 CMake : 4 find_package(TBB COMPONENTS tbb tbbmalloc REQUIRED) 6 add_executable(myapp myapp) 7 target_link_libraries(myapp led/tbb/tbb.dll) 毕竟大多数操作系统都是 Unix-like 嘛……就 Windows 喜欢搞特殊。 ## 更通用的方式：find_package 更好的做法是用 CMake 的 find_package 命令。 find_package(TBB REQUIRED) 会查找 /usr/lib/cmake/TBB/TBBConfig.cmake 这个配置文件，并根据里面的配置信息创建 target_link_libraries 链接 TBB::tbb 就可以正常工作了。 CMakeLists.txt main.cpp 1 add_executable(main main.cpp) 3 find_package(TBB REQUIRED) 4 target link libraries(main PUBLIC TBB::tbb) TBB::tbb 是一个伪对象 (imported)，除了他会指向

## Pain: What's a dependency bug? $ cmake --build build/ CMake Error at CMakeLists.txt:5 (find_package): By not providing "Findjsonlog.cmake" in CMAKE_MODULE_PATH this project has asked CMake adoptable for current CMake users - Ideally via normal CMake version upgrades ☐ Use existing find_package(...) calls ☐ Use existing install(EXPORT...) calls Should work with existing packaging approaches Library is treated the same: built-in source tree or prebuilt add_library(bar) # part of the build find_package(bar REQUIRED) # external to the build add_executable(foo) target_link_libraries(foo bar) # makes

} ## Properties: playing nice with ecosystem find_package(ZLIB REQUIRED) # find_package(ZLIB MODULE) target_link_libraries(... ZLIB::ZLIB) "includedirs": ["include"] adoption hints - Conclusions and next steps ## About CMake modules: Protobuf CMakeLists.txt find_package(protobuf CONFIG REQUIRED) add_executable(${PROJECT_NAME} test_package.cpp addressbook.proto) TARGET ${PROJECT_NAME} PROTOS addressbook.proto) ## About CMake modules: Protobuf CMakeLists.txt find_package(protobuf CONFIG REQUIRED) add_executable(${PROJECT_NAME} test_package.cpp addressbook.proto)

Find.cmake 模块，你也可以自己定义 Find模块，通过 SET(CMAKE_MODULE_PATH dir) 将其放入工程的某个目录中供工程使用，我们在后面的章节会详细介绍 FIND_PACKAGE 的使用方法和 Find 模块的编写。 FIND LIBRARY 示例: FIND_LIBRARY(libX X11 /usr/lib) IF(NOT libX) MESSAGE(fatal_ERROR 你现在还会觉得 cmake 简单吗？ 本章我们将着重介绍系统预定义的 Find 模块的使用以及自己编写 Find 模块，系统中提供了其他各种模块，一般情况需要使用 INCLUDE 指令显式的调用，FIND_PACKAGE 指令是一个特例，可以直接调用预定义的模块。 其实使用纯粹依靠 cmake 本身提供的基本指令来管理工程是一件非常复杂的事情，所以，cmake 设计成了可扩展的架构，可以通过编写一些通用的模块来扩展 build 目录进行外部构建即可。 现在我们要探讨的是使用 cmake 提供的 Findcurl 模块。 方法2，使用 Findcurl 模块。 向 src/CMakeLists.txt 中添加： FIND_PACKAGE(curl) IF(curl_FOUND) INCLUDE_DIRECTORIES(${curl_INCLUDE_DIR}) TARGET_LINK_LIBRARYES(curltest

3.15) project(compressor C) (continues on next page) find_package(ZLIB REQUIRED) add_executable(${PROJECT_NAME} src/main.c) target_link_libraries(${PROJECT_NAME} version: Listing 7: CMakeLists.txt cmake_minimum_required(VERSION 3.15) project(compressor C) find_package(ZLIB REQUIRED) message("Building with CMake version: ${CMAKE_VERSION}") add_executable(${PROJECT_NAME} set_target_properties(hello PROPERTIES PUBLIC_HEADER "include/hello.h") if (WITH_FMT) find_package(fmt) target_link_libraries(hello fmt::fmt) target_compile_definitions(hello PRIVATE USING_FMT=1)

3.15) project(compressor C) (continues on next page) find_package(ZLIB REQUIRED) add_executable(${PROJECT_NAME} src/main.c) target_link_libraries(${PROJECT_NAME} CMakeLists.txt cmake_minimum_required(VERSION 3.15) project(compressor C) (continues on next page) find_package(ZLIB REQUIRED) message("Building with CMake version: ${MAKE_VERSION}") add_executable(${PROJECT_NAME} set_target_properties(hello PROPERTIES PUBLIC_HEADER "include/hello.h") if (WITH_FMT) find_package(fmt) target_link_libraries(hello fmt::fmt) target_compile_definitions(hello PRIVATE USING_FMT=1)

3.15) project(compressor C) (continues on next page) find_package(ZLIB REQUIRED) add_executable(${PROJECT_NAME} src/main.c) target_link_libraries(${PROJECT_NAME} CMakeLists.txt cmake_minimum_required(VERSION 3.15) project(compressor C) (continues on next page) find_package(ZLIB REQUIRED) message("Building with CMake version: ${MAKE_VERSION}") add_executable(${PROJECT_NAME} set_target_properties(hello PROPERTIES PUBLIC_HEADER "include/hello.h") if (WITH_FMT) find_package(fmt) target_link_libraries(hello fmt::fmt) target_compile_definitions(hello PRIVATE USING_FMT=1)

3.15) project(compressor C) (continues on next page) find_package(ZLIB REQUIRED) add_executable(${PROJECT_NAME} src/main.c) target_link_libraries(${PROJECT_NAME} version: Listing 7: CMakeLists.txt cmake_minimum_required(VERSION 3.15) project(compressor C) find_package(ZLIB REQUIRED) message("Building with CMake version: ${CMake_VERSION}") add_executable({PROJECT_NAME} set_target_properties(hello PROPERTIES PUBLIC_HEADER "include/hello.h") if (WITH_FMT) find_package(fmt) target_link_libraries(hello fmt::fmt) target_compile_definitions(hello PRIVATE USING_FMT=1)