add_subdirectory("${__path}" "${CMAKE_CURRENT_BINARY_DIR}/.firstpass/${__name}")

`add_subdirectory("${__path}" "${CMAKE_CURRENT_BINARY_DIR}/.firstpass/${__name}")` 是一个CMake命令，用于向当前的CMakeLists.txt文件中添加一个子目录，并指定子目录的构建输出目录。

在这个命令中，`${__path}` 是要添加的子目录的路径或名称。`${CMAKE_CURRENT_BINARY_DIR}` 是当前处理的CMakeLists.txt文件的构建输出目录。`.firstpass/${__name}` 是指定的子目录的构建输出目录。

通过使用 `add_subdirectory` 命令并传递适当的参数，可以将子目录添加到项目中，并将其构建输出到指定的目录中。这样可以使项目的构建结果更加清晰和可管理。

希望这个解释对你有帮助！如果你还有其他问题，请随时提问。

相关问题

cmake_minimum_required(VERSION 3.8.0 FATAL_ERROR) project(mcu_kit VERSION 0.1.0 DESCRIPTION "mcu-kit SDK" LANGUAGES C ) set(PROJECT_BRIEF "vDiscovery") set(CMAKE_C_STANDARD 11) set(CMAKE_C_EXTENSIONS ON) set(CMAKE_C_STANDARD_REQUIRED ON) set(CMAKE_CXX_STANDARD 11) set(CMAKE_POSITION_INDEPENDENT_CODE ON) add_compile_options(-Wall) list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake") include(CMakePrintHelpers) include(ConfigureChecks) if(EXISTS "${PROJECT_SOURCE_DIR}/config.cmake") include(config.cmake) else() message(FATAL_ERROR "Can't find cmake.config file") endif() if(${CMAKE_CROSSCOMPILING}) set(LV_SIMULATOR_ON_PC OFF) else() set(LV_SIMULATOR_ON_PC ON) endif() configure_file( "${PROJECT_SOURCE_DIR}/base/base_sdk_version.h.in" "${PROJECT_SOURCE_DIR}/base/base_sdk_version.h" ) configure_file( "${PROJECT_SOURCE_DIR}/base/base_config.h.in" "${PROJECT_SOURCE_DIR}/base/base_config.h" ) set(CMAKE_INSTALL_BINDIR ${CMAKE_INSTALL_PREFIX}/bin) set(CMAKE_INSTALL_SBINDIR ${CMAKE_INSTALL_PREFIX}/sbin) set(CMAKE_INSTALL_LIBDIR ${CMAKE_INSTALL_PREFIX}/lib) set(CMAKE_INSTALL_INCLUDEDIR ${CMAKE_INSTALL_PREFIX}/include) set(CMAKE_INSTALL_SYSCONFDIR ${CMAKE_INSTALL_PREFIX}/etc) set(CMAKE_INSTALL_SHARESTATEDIR ${CMAKE_INSTALL_PREFIX}/com) set(CMAKE_INSTALL_LOCALSTATEDIR ${CMAKE_INSTALL_PREFIX}/var) set(CMAKE_INSTALL_INFODIR ${CMAKE_INSTALL_PREFIX}/info) set(CMAKE_INSTALL_LOCALEDIR ${CMAKE_INSTALL_PREFIX}/locate) set(CMAKE_INSTALL_MANDIR ${CMAKE_INSTALL_PREFIX}/man) set(CMAKE_INSTALL_DOCDIR ${CMAKE_INSTALL_PREFIX}/doc) set(CMAKE_INSTALL_RESDIR ${CMAKE_INSTALL_PREFIX}) include(PrepareInstall) set(KIT_ROOT_DIR ${CMAKE_SOURCE_DIR}) add_subdirectory("base") # add_subdirectory("third-party") add_subdirectory("lib") add_subdirectory("drivers") add_subdirectory("framework") add_subdirectory("sysapp") add_subdirectory("app") include(GeneratePkgConfig) include(Linux-kitInfo)详细注释一下这段代码

这段代码是一个 CMakeLists.txt 文件，用于构建一个名为 "mcu_kit" 的项目。下面是对每行代码的详细注释：

cmake_minimum_required(VERSION 3.8.0 FATAL_ERROR)

指定最低的 CMake 版本，如果当前版本不符合要求，则提示错误。

project(mcu_kit VERSION 0.1.0 DESCRIPTION "mcu-kit SDK" LANGUAGES C)

定义项目名称、版本、描述和使用的编程语言。

set(PROJECT_BRIEF "vDiscovery")

设置一个变量，用于描述项目简介。

set(CMAKE_C_STANDARD 11)
set(CMAKE_C_EXTENSIONS ON)
set(CMAKE_C_STANDARD_REQUIRED ON)
set(CMAKE_CXX_STANDARD 11)

指定使用的 C 和 C++ 标准版本。

set(CMAKE_POSITION_INDEPENDENT_CODE ON)

启用位置独立代码（PIC）选项。

add_compile_options(-Wall)

添加编译选项，这里添加了 -Wall 选项，表示开启所有警告。

list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")

将自定义的 CMake 模块路径添加到 CMAKE_MODULE_PATH 变量中。

include(CMakePrintHelpers)
include(ConfigureChecks)

包含两个自定义的 CMake 模块，用于输出调试信息和配置检查。

if(EXISTS "${PROJECT_SOURCE_DIR}/config.cmake")
    include(config.cmake)
else()
    message(FATAL_ERROR "Can't find cmake.config file")
endif()

如果存在 config.cmake 文件，则包含它，否则输出错误信息并停止构建。

if(${CMAKE_CROSSCOMPILING})
    set(LV_SIMULATOR_ON_PC OFF)
else()
    set(LV_SIMULATOR_ON_PC ON)
endif()

根据交叉编译标志设置变量 LV_SIMULATOR_ON_PC。如果正在交叉编译，则设置为 OFF；否则设置为 ON。

configure_file(
    "${PROJECT_SOURCE_DIR}/base/base_sdk_version.h.in"
    "${PROJECT_SOURCE_DIR}/base/base_sdk_version.h"
)
configure_file(
    "${PROJECT_SOURCE_DIR}/base/base_config.h.in"
    "${PROJECT_SOURCE_DIR}/base/base_config.h"
)

配置文件模板，用于生成编译时需要的头文件。

set(CMAKE_INSTALL_BINDIR ${CMAKE_INSTALL_PREFIX}/bin)
set(CMAKE_INSTALL_SBINDIR ${CMAKE_INSTALL_PREFIX}/sbin)
set(CMAKE_INSTALL_LIBDIR ${CMAKE_INSTALL_PREFIX}/lib)
set(CMAKE_INSTALL_INCLUDEDIR ${CMAKE_INSTALL_PREFIX}/include)
set(CMAKE_INSTALL_SYSCONFDIR ${CMAKE_INSTALL_PREFIX}/etc)
set(CMAKE_INSTALL_SHARESTATEDIR ${CMAKE_INSTALL_PREFIX}/com)
set(CMAKE_INSTALL_LOCALSTATEDIR ${CMAKE_INSTALL_PREFIX}/var)
set(CMAKE_INSTALL_INFODIR ${CMAKE_INSTALL_PREFIX}/info)
set(CMAKE_INSTALL_LOCALEDIR ${CMAKE_INSTALL_PREFIX}/locate)
set(CMAKE_INSTALL_MANDIR ${CMAKE_INSTALL_PREFIX}/man)
set(CMAKE_INSTALL_DOCDIR ${CMAKE_INSTALL_PREFIX}/doc)
set(CMAKE_INSTALL_RESDIR ${CMAKE_INSTALL_PREFIX})

设置安装目录的各个子目录。

include(PrepareInstall)

包含一个自定义的 CMake 模块，用于准备安装目录。

set(KIT_ROOT_DIR ${CMAKE_SOURCE_DIR})

设置变量 KIT_ROOT_DIR 的值为源代码目录。

add_subdirectory("base")
add_subdirectory("lib")
add_subdirectory("drivers")
add_subdirectory("framework")
add_subdirectory("sysapp")
add_subdirectory("app")

添加子目录，用于构建项目的各个模块。每个子目录都包含了相应的 CMakeLists.txt 文件。

# toplevel CMakeLists.txt for a catkin workspace # catkin/cmake/toplevel.cmake cmake_minimum_required(VERSION 3.0.2) project(Project) set(CATKIN_TOPLEVEL TRUE) # search for catkin within the workspace set(_cmd "catkin_find_pkg" "catkin" "${CMAKE_SOURCE_DIR}") execute_process(COMMAND ${_cmd} RESULT_VARIABLE _res OUTPUT_VARIABLE _out ERROR_VARIABLE _err OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_STRIP_TRAILING_WHITESPACE ) if(NOT _res EQUAL 0 AND NOT _res EQUAL 2) # searching fot catkin resulted in an error string(REPLACE ";" " " _cmd_str "${_cmd}") message(FATAL_ERROR "Search for 'catkin' in workspace failed (${_cmd_str}): ${_err}") endif() # include catkin from workspace or via find_package() if(_res EQUAL 0) set(catkin_EXTRAS_DIR "${CMAKE_SOURCE_DIR}/${_out}/cmake") # include all.cmake without add_subdirectory to let it operate in same scope include(${catkin_EXTRAS_DIR}/all.cmake NO_POLICY_SCOPE) add_subdirectory("${_out}") else() # use either CMAKE_PREFIX_PATH explicitly passed to CMake as a command line argument # or CMAKE_PREFIX_PATH from the environment if(NOT DEFINED CMAKE_PREFIX_PATH) if(NOT "$ENV{CMAKE_PREFIX_PATH}" STREQUAL "") if(NOT WIN32) string(REPLACE ":" ";" CMAKE_PREFIX_PATH $ENV{CMAKE_PREFIX_PATH}) else() set(CMAKE_PREFIX_PATH $ENV{CMAKE_PREFIX_PATH}) endif() endif() endif() # list of catkin workspaces set(catkin_search_path "") foreach(path ${CMAKE_PREFIX_PATH}) if(EXISTS "${path}/.catkin") list(FIND catkin_search_path ${path} _index) if(_index EQUAL -1) list(APPEND catkin_search_path ${path}) endif() endif() endforeach() # search for catkin in all workspaces set(CATKIN_TOPLEVEL_FIND_PACKAGE TRUE) find_package(catkin QUIET NO_POLICY_SCOPE PATHS ${catkin_search_path} NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT_PATH) unset(CATKIN_TOPLEVEL_FIND_PACKAGE) if(NOT catkin_FOUND) message(FATAL_ERROR "find_package(catkin) failed. catkin was neither found in the workspace nor in the CMAKE_PREFIX_PATH. One reason may be that no ROS setup.sh was sourced before.") endif() endif() catkin_workspace()在哪添加target_link_libraries(your_target_name avcodec avformat swscale)

在您的 CMakeLists.txt 文件中，将 `target_link_libraries()` 指令添加到 `add_subdirectory("${_out}")` 的下方。具体位置如下所示：

...

# include catkin from workspace or via find_package()
if(_res EQUAL 0)
  set(catkin_EXTRAS_DIR "${CMAKE_SOURCE_DIR}/${_out}/cmake")
  # include all.cmake without add_subdirectory to let it operate in same scope
  include(${catkin_EXTRAS_DIR}/all.cmake NO_POLICY_SCOPE)
  add_subdirectory("${_out}")

  # Add the target_link_libraries() here
  target_link_libraries(your_target_name avcodec avformat swscale)

else
  # use either CMAKE_PREFIX_PATH explicitly passed to CMake as a command line argument
  # or CMAKE_PREFIX_PATH from the environment
  if(NOT DEFINED CMAKE_PREFIX_PATH)
    if(NOT "$ENV{CMAKE_PREFIX_PATH}" STREQUAL "")
      if(NOT WIN32)
        string(REPLACE ":" ";" CMAKE_PREFIX_PATH $ENV{CMAKE_PREFIX_PATH})
      else()
        set(CMAKE_PREFIX_PATH $ENV{CMAKE_PREFIX_PATH})
      endif()
    endif()
  endif()

  ...
endif()

...

请注意将 `your_target_name` 替换为您实际的目标名称。这将在生成目标时链接 avcodec、avformat 和 swscale 库。

如果您还有其他问题，请随时提问。