C++ 如何将特征库添加到cmake c++；通过FetchContent创建项目

加本征通孔

FetchContent_Declare(
  eigen
  GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
  GIT_TAG        3.3.9
)

FetchContent_GetProperties(eigen)

if(NOT eigen_POPULATED)
    FetchContent_Populate(eigen)
    add_subdirectory(${eigen_SOURCE_DIR} ${eigen_BINARY_DIR})
endif()

find_package (Eigen3 3.3 REQUIRED NO_MODULE) 

告诉我错误

CMake Error at o/b/x64-Debug/_deps/eigen-build/Eigen3Config.cmake:20 (include):
  The file

    D:/XXX/o/b/x64-Debug/_deps/eigen-build/Eigen3Targets.cmake

  was generated by the export() command.  It may not be used as the argument
  to the include() command.  Use ALIAS targets instead to refer to targets by
  alternative names.        D:\XXX\o/b/x64-Debug/_deps/eigen-build/Eigen3Config.cmake   20

但是手动下载Eigen并添加它就可以了

add_subdirectory("${PROJECT_SOURCE_DIR}/extern/eigen")
find_package (Eigen3 3.3 REQUIRED NO_MODULE) 

---

有什么想法吗？

好吧，我放弃了FetchContent，我也尝试过这个，但这个对我也不起作用

我现在使用ExternalProject（）获取和链接eigen

include(ExternalProject)

set(EIGEN_BUILD_DIR   ${CMAKE_BINARY_DIR}/eigen)
set(EIGEN_INSTALL_DIR ${CMAKE_SOURCE_DIR}/include/eigen3)
set(EIGEN_INCLUDE_DIR ${EIGEN_INSTALL_DIR})

ExternalProject_Add(
    eigen
    URL https://gitlab.com/libeigen/eigen/-/archive/3.3.7/eigen-3.3.7.tar.gz
    PREFIX ${EIGEN_BUILD_DIR}
    CONFIGURE_COMMAND ""
    BUILD_COMMAND ""
    INSTALL_COMMAND
      ${CMAKE_COMMAND} -E copy_directory ${EIGEN_BUILD_DIR}/src/eigen/Eigen ${EIGEN_INCLUDE_DIR}/Eigen 
      && ${CMAKE_COMMAND} -E copy_directory ${EIGEN_BUILD_DIR}/src/eigen/unsupported ${EIGEN_INCLUDE_DIR}/unsupported
    TEST_COMMAND ""
)
include_directories(SYSTEM ${EIGEN_INCLUDE_DIR})

此外，还必须使用add_依赖项

add_executable(test1 "test1.cpp")
add_dependencies(test1 eigen)

以任何顺序：

• Eigen仅在主机上提供

  别名
  目标
  
  参考：
  
  

• FetchContent的使用可能是

• 有关

  find_package（）

  和

  FetchContent（）/add_子目录（）

  的信息，请参阅

---

如果使用

add\u子目录

方法包含外部项目，则不需要

find\u package

。如果没有find package target\u link\u库，则会抛出错误非常感谢，这非常有效：）

include(FetchContent)
FetchContent_Declare(
  Eigen
  GIT_REPOSITORY https://gitlab.com/libeigen/eigen.git
  GIT_TAG master
  GIT_SHALLOW TRUE
  GIT_PROGRESS TRUE)
set(EIGEN_BUILD_DOC OFF)
# note: To disable eigen tests,
# you should put this code in a add_subdirectory to avoid to change
# BUILD_TESTING for your own project too since variables are directory
# scoped
set(BUILD_TESTING OFF)
set(EIGEN_BUILD_PKGCONFIG OFF)
set( OFF)
FetchContent_MakeAvailable(Eigen)
...
target_link_libraries(YourTarget PRIVATE Eigen3::Eigen)