如何在CMake中使用Qhull作为外部项目？

Question

我曾尝试在CMake中使用QHull和libqhullcpp作为外部项目，但没有成功。

到目前为止，我已经使用了这些命令，它是this的修改版本

include(ExternalProject)
ExternalProject_add(qhull
        GIT_REPOSITORY "https://github.com/qhull/qhull.git"
        GIT_TAG "2019.1"
        GIT_PROGRESS TRUE
        SOURCE_DIR ${CMAKE_SOURCE_DIR}/thirdparty/qhull
        BINARY_DIR ${CMAKE_BINARY_DIR}/thirdparty-build/qhull
        CMAKE_ARGS "-DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/thirdparty-install"
        CMAKE_CACHE_ARGS "-DCMAKE_POSITION_INDEPENDENT_CODE:BOOL=true"
        )


### qhullstatic reentrant library
add_library(libqhullstatic_r STATIC IMPORTED)
set_property(TARGET libqhullstatic_r PROPERTY IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/thirdparty-build/qhull/${CMAKE_STATIC_LIBRARY_PREFIX}qhullstatic_r${CMAKE_STATIC_LIBRARY_SUFFIX})
set_property(TARGET libqhullstatic_r PROPERTY IMPORTED_LOCATION_DEBUG ${CMAKE_BINARY_DIR}/thirdparty-build/qhull/Debug/${CMAKE_STATIC_LIBRARY_PREFIX}qhullstatic_r${CMAKE_STATIC_LIBRARY_SUFFIX})
set_property(TARGET libqhullstatic_r PROPERTY IMPORTED_LOCATION_RELEASE ${CMAKE_BINARY_DIR}/thirdparty-build/qhull/Release/${CMAKE_STATIC_LIBRARY_PREFIX}qhullstatic_r${CMAKE_STATIC_LIBRARY_SUFFIX})
add_dependencies(libqhullstatic_r qhull)
### qhullcpp library
add_library(libqhullcpp STATIC IMPORTED)
set_property(TARGET libqhullcpp PROPERTY IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/thirdparty-build/qhull/${CMAKE_STATIC_LIBRARY_PREFIX}qhullcpp${CMAKE_STATIC_LIBRARY_SUFFIX})
set_property(TARGET libqhullcpp PROPERTY IMPORTED_LOCATION_DEBUG ${CMAKE_BINARY_DIR}/thirdparty-build/qhull/Debug/${CMAKE_STATIC_LIBRARY_PREFIX}qhullcpp${CMAKE_STATIC_LIBRARY_SUFFIX})
set_property(TARGET libqhullcpp PROPERTY IMPORTED_LOCATION_RELEASE ${CMAKE_BINARY_DIR}/thirdparty-build/qhull/Release/${CMAKE_STATIC_LIBRARY_PREFIX}qhullcpp${CMAKE_STATIC_LIBRARY_SUFFIX})
set_property(TARGET libqhullcpp PROPERTY INTERFACE_LINK_LIBRARIES libqhullstatic_r)
add_dependencies(libqhullcpp qhull)

add_executable(${PROJECT_NAME} src/main.cpp)
target_link_libraries(${PROJECT_NAME} ${libqhullcpp})

我的项目找不到任何Qhull代码文件，如果我添加

#include <libqhullcpp/Qhull.h> 
orgQhull::Qhull qhull;

到我的项目，它将抛出这个编译错误：

CMakeFiles/MyProject.dir/src/main.cpp.o: In function `main':
~/MyProject/src/main.cpp:108: undefined reference to `orgQhull::Qhull::Qhull()'
~/MyProject/src/main.cpp:108: undefined reference to `orgQhull::Qhull::~Qhull()'
~/MyProject/src/main.cpp:108: undefined reference to `orgQhull::Qhull::~Qhull()'
collect2: error: ld returned 1 exit status
CMakeFiles/MyProject.dir/build.make:83: recipe for target 'MyProject' failed
make[3]: *** [MyProject] Error 1
CMakeFiles/Makefile2:104: recipe for target 'CMakeFiles/MyProject.dir/all' failed
make[2]: *** [CMakeFiles/MyProject.dir/all] Error 2
CMakeFiles/Makefile2:111: recipe for target 'CMakeFiles/MyProject.dir/rule' failed
make[1]: *** [CMakeFiles/MyProject.dir/rule] Error 2
Makefile:131: recipe for target 'MyProject' failed
make: *** [MyProject] Error 2

Answer 1

我已经修改了你的CMakeLists.txt文件并做了一些优化，所以你不需要在源代码中构建。我的tree提供了以下功能：

--QHull
|   |--CMakeLists.txt
|   |--CMakeLists.txt.in
|   |--src
|       |--main.cpp
|--build

使用CMakeLists.txt

cmake_minimum_required(VERSION 3.0)
project(TestQHull)

configure_file(CMakeLists.txt.in qhull-download/CMakeLists.txt)

execute_process(COMMAND "${CMAKE_COMMAND}" -G "${CMAKE_GENERATOR}" .
    WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/qhull-download"
)
execute_process(COMMAND "${CMAKE_COMMAND}" --build .
    WORKING_DIRECTORY "${CMAKE_BINARY_DIR}/qhull-download"
)

add_subdirectory("${CMAKE_BINARY_DIR}/qhull-src"
                 "${CMAKE_BINARY_DIR}/qhull-build"
)

include_directories(${CMAKE_BINARY_DIR}/qhull-src/src)
link_directories(${CMAKE_BINARY_DIR}/qhull-build)

### qhullstatic reentrant library
add_library(libqhullstatic_r STATIC IMPORTED)
set_property(TARGET libqhullstatic_r PROPERTY IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/qhull-build/${CMAKE_STATIC_LIBRARY_PREFIX}qhullstatic_r${CMAKE_STATIC_LIBRARY_SUFFIX})
add_dependencies(libqhullstatic_r qhull)
### qhullcpp library
add_library(libqhullcpp STATIC IMPORTED)
set_property(TARGET libqhullcpp PROPERTY IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/qhull-build/${CMAKE_STATIC_LIBRARY_PREFIX}qhullcpp${CMAKE_STATIC_LIBRARY_SUFFIX})
set_property(TARGET libqhullcpp PROPERTY INTERFACE_LINK_LIBRARIES libqhullstatic_r)
add_dependencies(libqhullcpp qhull)

add_executable(${PROJECT_NAME} src/main.cpp)
target_link_libraries(${PROJECT_NAME} libqhullstatic_r libqhullcpp)

和

CMakeLists.txt.in包含以下内容：

cmake_minimum_required(VERSION 3.0)
project(qhull-download NONE)

include(ExternalProject)

ExternalProject_add(qhull
    GIT_REPOSITORY https://github.com/qhull/qhull.git
    GIT_TAG 2019.1
    GIT_PROGRESS TRUE
    SOURCE_DIR ${CMAKE_BINARY_DIR}/qhull-src
    BINARY_DIR ${CMAKE_BINARY_DIR}/qhull-build
    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}
    CMAKE_CACHE_ARGS ""
    CONFIGURE_COMMAND ""
    BUILD_COMMAND ""
    INSTALL_COMMAND ""
    TEST_COMMAND ""
)

如果你使用cd build && cmake ../QHull，它将会下载并开始为你构建qhull。

唯一的缺点是：ExternalProjects将${CMAKE_SOURCE_DIR}\QHull\src保留为INCLUDE_DIRECTORIES，而不是所需的${CMAKE_BINARY_DIR}\qhull-src\src。

因为我无法修复这个问题，所以我的变通方法是在cmake配置步骤之后，在生成器脚本(例如我的例子中是build.ninja )中用-I${CMAKE_SOURCE_DIR}\QHull\src替换-I${CMAKE_SOURCE_DIR}\QHull\src。

在那之后，我能够构建自己的示例main.cpp。