128

我有一个将静态库作为目标导出的项目 A：

install(TARGETS alib DESTINATION lib EXPORT project_a-targets)
install(EXPORT project_a-targets DESTINATION lib/alib)

现在我想将项目 A 用作项目 B 的外部项目并包含其构建目标：

ExternalProject_Add(project_a
  URL ...project_a.tar.gz
  PREFIX ${CMAKE_CURRENT_BINARY_DIR}/project_a
  CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
)

include(${CMAKE_CURRENT_BINARY_DIR}/lib/project_a/project_a-targets.cmake)

问题是项目B的CMakeLists运行时包含文件还不存在。

有没有办法让包含依赖于正在构建的外部项目？

更新：我根据这个和我遇到的其他常见问题编写了一个简短的CMake by Example 教程。

4

5 回答 5

72

我认为您在这里混合了两种不同的范例。

如您所述，高度灵活的ExternalProject模块在构建时运行其命令，因此您不能直接使用项目 A 的导入文件，因为它仅在安装项目 A 后创建。

如果您想要include项目 A 的导入文件，则必须在调用项目 B 的 CMakeLists.txt 之前手动安装项目 A - 就像以这种方式或通过find_file//添加的任何其他第三方依赖项一样。find_libraryfind_package

如果要使用ExternalProject_Add，则需要在 CMakeLists.txt 中添加类似以下内容：

ExternalProject_Add(project_a
  URL ...project_a.tar.gz
  PREFIX ${CMAKE_CURRENT_BINARY_DIR}/project_a
  CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
)

include(${CMAKE_CURRENT_BINARY_DIR}/lib/project_a/project_a-targets.cmake)

ExternalProject_Get_Property(project_a install_dir)
include_directories(${install_dir}/include)

add_dependencies(project_b_exe project_a)
target_link_libraries(project_b_exe ${install_dir}/lib/alib.lib)
于 2013-03-02T15:22:15.977 回答
25

这篇文章有一个合理的答案：

CMakeLists.txt.in：

cmake_minimum_required(VERSION 2.8.2)

project(googletest-download NONE)

include(ExternalProject)
ExternalProject_Add(googletest
  GIT_REPOSITORY    https://github.com/google/googletest.git
  GIT_TAG           master
  SOURCE_DIR        "${CMAKE_BINARY_DIR}/googletest-src"
  BINARY_DIR        "${CMAKE_BINARY_DIR}/googletest-build"
  CONFIGURE_COMMAND ""
  BUILD_COMMAND     ""
  INSTALL_COMMAND   ""
  TEST_COMMAND      ""
)

CMakeLists.txt：

# Download and unpack googletest at configure time
configure_file(CMakeLists.txt.in
               googletest-download/CMakeLists.txt)
execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
  WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download )
execute_process(COMMAND ${CMAKE_COMMAND} --build .
  WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download )

# Prevent GoogleTest from overriding our compiler/linker options
# when building with Visual Studio
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)

# Add googletest directly to our build. This adds
# the following targets: gtest, gtest_main, gmock
# and gmock_main
add_subdirectory(${CMAKE_BINARY_DIR}/googletest-src
                 ${CMAKE_BINARY_DIR}/googletest-build)

# The gtest/gmock targets carry header search path
# dependencies automatically when using CMake 2.8.11 or
# later. Otherwise we have to add them here ourselves.
if (CMAKE_VERSION VERSION_LESS 2.8.11)
  include_directories("${gtest_SOURCE_DIR}/include"
                      "${gmock_SOURCE_DIR}/include")
endif()

# Now simply link your own targets against gtest, gmock,
# etc. as appropriate

但是，它看起来确实很hacky。我想提出一个替代解决方案 - 使用 Git 子模块。

cd MyProject/dependencies/gtest
git submodule add https://github.com/google/googletest.git
cd googletest
git checkout release-1.8.0
cd ../../..
git add *
git commit -m "Add googletest"

然后，MyProject/dependencies/gtest/CMakeList.txt您可以执行以下操作：

cmake_minimum_required(VERSION 3.3)

if(TARGET gtest) # To avoid diamond dependencies; may not be necessary depending on you project.
    return()
endif()

add_subdirectory("googletest")

我还没有广泛尝试过，但它看起来更干净。

编辑：这种方法有一个缺点：子目录可能会运行install()您不想要的命令。这篇文章有一种禁用它们的方法，但它有问题并且对我不起作用。

编辑2：如果您使用add_subdirectory("googletest" EXCLUDE_FROM_ALL)它似乎意味着install()默认情况下不使用子目录中的命令。

于 2017-01-23T11:42:01.717 回答
8

编辑：CMake 现在对此具有内置支持。请参阅使用FetchContent的新答案。

您还可以在辅助 make 过程中强制构建依赖目标

请参阅我对相关主题的回答。

于 2014-05-09T20:09:32.363 回答
3

我正在寻找类似的解决方案。此处的回复和顶部的教程提供了丰富的信息。我研究了这里提到的帖子/博客以成功建立我的。我发布了完整的 CMakeLists.txt 为我工作。我想，这将有助于作为初学者的基本模板。

"CMakeLists.txt"

cmake_minimum_required(VERSION 3.10.2)

# Target Project
project (ClientProgram)

# Begin: Including Sources and Headers
include_directories(include)
file (GLOB SOURCES "src/*.c")
# End: Including Sources and Headers


# Begin: Generate executables
add_executable (ClientProgram ${SOURCES})
# End: Generate executables


# This Project Depends on External Project(s) 
include (ExternalProject)

# Begin: External Third Party Library
set (libTLS ThirdPartyTlsLibrary)
ExternalProject_Add (${libTLS}
PREFIX          ${CMAKE_CURRENT_BINARY_DIR}/${libTLS}
# Begin: Download Archive from Web Server
URL             http://myproject.com/MyLibrary.tgz
URL_HASH        SHA1=<expected_sha1sum_of_above_tgz_file>
DOWNLOAD_NO_PROGRESS ON
# End: Download Archive from Web Server

# Begin: Download Source from GIT Repository
#    GIT_REPOSITORY  https://github.com/<project>.git
#    GIT_TAG         <Refer github.com releases -> Tags>
#    GIT_SHALLOW     ON
# End: Download Source from GIT Repository

# Begin: CMAKE Comamnd Argiments
CMAKE_ARGS      -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_CURRENT_BINARY_DIR}/${libTLS}
CMAKE_ARGS      -DUSE_SHARED_LIBRARY:BOOL=ON
# End: CMAKE Comamnd Argiments    
)

# The above ExternalProject_Add(...) construct wil take care of \
# 1. Downloading sources
# 2. Building Object files
# 3. Install under DCMAKE_INSTALL_PREFIX Directory

# Acquire Installation Directory of 
ExternalProject_Get_Property (${libTLS} install_dir)

# Begin: Importing Headers & Library of Third Party built using ExternalProject_Add(...)
# Include PATH that has headers required by Target Project
include_directories (${install_dir}/include)

# Import librarues from External Project required by Target Project
add_library (lmytls SHARED IMPORTED)
set_target_properties (lmytls PROPERTIES IMPORTED_LOCATION ${install_dir}/lib/libmytls.so)
add_library (lmyxdot509 SHARED IMPORTED)
set_target_properties(lmyxdot509 PROPERTIES IMPORTED_LOCATION ${install_dir}/lib/libmyxdot509.so)

# End: Importing Headers & Library of Third Party built using ExternalProject_Add(...)
# End: External Third Party Library

# Begin: Target Project depends on Third Party Component
add_dependencies(ClientProgram ${libTLS})
# End: Target Project depends on Third Party Component

# Refer libraries added above used by Target Project
target_link_libraries (ClientProgram lmytls lmyxdot509)
于 2020-06-07T15:09:55.727 回答
1

cmakeExternalProject_Add确实可以使用，但我不喜欢它 - 它在构建、连续轮询等期间执行某些操作……我更愿意在构建阶段构建项目，仅此而已。我曾ExternalProject_Add多次尝试覆盖，不幸的是没有成功。

然后我也尝试添加 git 子模块，但这会拖拽整个 git 存储库，而在某些情况下，我只需要整个 git 存储库的子集。我检查过的内容 - 确实可以执行稀疏 git checkout，但这需要单独的函数，我在下面写了。

#-----------------------------------------------------------------------------
#
# Performs sparse (partial) git checkout
#
#   into ${checkoutDir} from ${url} of ${branch}
#
# List of folders and files to pull can be specified after that.
#-----------------------------------------------------------------------------
function (SparseGitCheckout checkoutDir url branch)
    if(EXISTS ${checkoutDir})
        return()
    endif()

    message("-------------------------------------------------------------------")
    message("sparse git checkout to ${checkoutDir}...")
    message("-------------------------------------------------------------------")

    file(MAKE_DIRECTORY ${checkoutDir})

    set(cmds "git init")
    set(cmds ${cmds} "git remote add -f origin --no-tags -t master ${url}")
    set(cmds ${cmds} "git config core.sparseCheckout true")

    # This command is executed via file WRITE
    # echo <file or folder> >> .git/info/sparse-checkout")

    set(cmds ${cmds} "git pull --depth=1 origin ${branch}")

    # message("In directory: ${checkoutDir}")

    foreach( cmd ${cmds})
        message("- ${cmd}")
        string(REPLACE " " ";" cmdList ${cmd})

        #message("Outfile: ${outFile}")
        #message("Final command: ${cmdList}")

        if(pull IN_LIST cmdList)
            string (REPLACE ";" "\n" FILES "${ARGN}")
            file(WRITE ${checkoutDir}/.git/info/sparse-checkout ${FILES} )
        endif()

        execute_process(
            COMMAND ${cmdList}
            WORKING_DIRECTORY ${checkoutDir}
            RESULT_VARIABLE ret
        )

        if(NOT ret EQUAL "0")
            message("error: previous command failed, see explanation above")
            file(REMOVE_RECURSE ${checkoutDir})
            break()
        endif()
    endforeach()

endfunction()


SparseGitCheckout(${CMAKE_BINARY_DIR}/catch_197 https://github.com/catchorg/Catch2.git v1.9.7 single_include)
SparseGitCheckout(${CMAKE_BINARY_DIR}/catch_master https://github.com/catchorg/Catch2.git master single_include)

我在下面添加了两个函数调用，只是为了说明如何使用该函数。

有人可能不喜欢检查主干/主干，因为那个可能被破坏了——那么总是可以指定特定的标签。

检出只会执行一次，直到您清除缓存文件夹。

于 2019-09-28T12:46:40.213 回答