为 NetCDF C++ 创建 CMake

Question

我正在尝试为我使用 NetCDF 的项目创建一个 CMake 文件。我是 CMake 的新手（这是我的第一次尝试），所以如果其中一些内容很明显，我深表歉意。

为了安装 NetCDF，我按照 git 指南中显示的步骤进行操作 here

我相信我的步骤是正确的。我正在尝试使用 NetCDF C++ 库，但出于编译目的，我还必须安装 C 库。我这样做是通过使用：

sudo apt install libnetcdf-dev

当我运行以下命令时，我收到适当的输出（根据 git 指南）：

nc-config --has-nc4

到目前为止一切顺利...我希望。这是我的 CMakeLists.Txt:

cmake_minimum_required(VERSION 3.16)

project(orbit LANGUAGES CXX)

# ##############################################################################
# Conan Packages
# ##############################################################################

set(CONAN_EXTRA_REQUIRES "")  set(CONAN_EXTRA_OPTIONS "")

list(APPEND CONAN_EXTRA_REQUIRES boost/1.73.0) list(APPEND CONAN_EXTRA_REQUIRES eigen/3.3.7)

if(BUILD_SHARED_LIBS)   list(APPEND CONAN_EXTRA_OPTIONS "Pkg:shared=True") endif()

include(cmake/Conan.cmake) run_conan()

# ############################################################################## 
find_file(CMAKE_PREFIX_PATH netCDFCxxConfig.cmake) 
find_package (NetCDF REQUIRED) include_directories(${NETCDF_INCLUDES})

# set(SOURCE test.cpp player.cpp player.hpp)

# include_directories(include)

# Search all .cpp files 
file(GLOB_RECURSE SOURCE_FILES "*.cpp")

add_executable(test ${SOURCE_FILES})

target_link_libraries(test 
                      PRIVATE
                          CONAN_PKG::boost
                          CONAN_PKG::eigen

                          ${NETCDF_LIBRARIES_CXX})

这是错误输出：

CMake Error at CMakeLists.txt:24 (find_package):
  By not providing "FindNetCDF.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "NetCDF", but
  CMake did not find one.

  Could not find a package configuration file provided by "NetCDF" with any
  of the following names:

    NetCDFConfig.cmake
    netcdf-config.cmake

  Add the installation prefix of "NetCDF" to CMAKE_PREFIX_PATH or set
  "NetCDF_DIR" to a directory containing one of the above files.  If "NetCDF"
  provides a separate development package or SDK, be sure it has been
  installed.

我的理解是这个错误是因为我没有正确执行 git 指南中的以下行：

Make sure that either nc-config is in your PATH, or that the location of netCDFConfig.cmake is in CMAKE_PREFIX_PATH.

我已经尝试将 nc-config 添加到我的 PATH，运行ning:

export PATH="nc-config:$PATH"

但这并不能解决问题...

此外，我试图在我的电脑中找到一个 netCDFConfig.cmake 文件，但它似乎不存在。我确实有一个 netCDFCxxConfig.cmake，但我不确定这是否相同，或者我如何才能在这里使用它。

有没有人遇到过这个问题，知道如何解决？任何帮助将不胜感激，如果过去提供过这样的解决方案，我深表歉意。

编辑：

我能够让 CMake 最终找到该文件，但现在它在寻找另一个文件时迷路了...这是它在我的原始文件中找不到的文件 post:

# NetCDF CXX Configuration Summary

####### Expanded from @PACKAGE_INIT@ by configure_package_config_file() #######
####### Any changes to this file will be overwritten by the next CMake run ####
####### The input file was netCDFCxxConfig.cmake.in                            ########

get_filename_component(PACKAGE_PREFIX_DIR "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE)

macro(set_and_check _var _file)
  set(${_var} "${_file}")
  if(NOT EXISTS "${_file}")
    message(FATAL_ERROR "File or directory ${_file} referenced by variable ${_var} does not exist !")
  endif()
endmacro()

macro(check_required_components _NAME)
  foreach(comp ${${_NAME}_FIND_COMPONENTS})
    if(NOT ${_NAME}_${comp}_FOUND)
      if(${_NAME}_FIND_REQUIRED_${comp})
        set(${_NAME}_FOUND FALSE)
      endif()
    endif()
  endforeach()
endmacro()

####################################################################################

include(CMakeFindDependencyMacro)

if (1)
  if(EXISTS "")
    set(netCDF_ROOT "")
  endif()
  if(EXISTS "/usr/lib/x86_64-linux-gnu/cmake/netCDF")
    set(netCDF_DIR "/usr/lib/x86_64-linux-gnu/cmake/netCDF")
  endif()
  find_dependency(netCDF)
  set(NETCDF_C_LIBRARY ${netCDF_LIBRARIES})
  set(NETCDF_C_INCLUDE_DIR ${netCDF_INCLUDE_DIR})
else()
  set(NETCDF_C_LIBRARY "netcdf")
  set(NETCDF_C_INCLUDE_DIR "/usr/include")
endif()

if (NOT TARGET netCDF::netcdf)
  add_library(netCDF::netcdf UNKNOWN IMPORTED)
  set_target_properties(netCDF::netcdf PROPERTIES
    IMPORTED_LOCATION "${NETCDF_C_LIBRARY}"
    INTERFACE_INCLUDE_DIRECTORIES "${NETCDF_C_INCLUDE_DIR}"
  )
endif()

include("${CMAKE_CURRENT_LIST_DIR}/netcdf-cxx4Targets.cmake")

最后一行是所有错误的地方。这是找到 netcdf-cxx4Targets.cmake.

时出现问题的地方

我刚刚post编辑的文件在目录中：netcd-cxx4/build netcdf-cxx4Targets.cmake 在目录中：

netcd-cxx4/build/CMakeFiles/Export/lib/cmake/netCDF

所以第一个应该能找到另一个？

Answer 1

netCDFCxxConfig.cmake 文件就是您要使用的文件。通过快速查看 GitHub repository，有一个用于此文件 (netCDFCxxConfig.cmake.in) 的模板，但没有用于 netCDFConfig.cmake.in 的模板。因此，我的结论是维护者可能在某个时候更改了配置文件名，并且忘记将他们的 README 文档更新为 netCDFCxxConfig.cmake.

您可以将 netCDFCxxConfig.cmake 文件的位置添加到 CMake 文件中的 CMAKE_PREFIX_PATH 列表变量。然后，link到netCDFCxxConfig.cmake文件中定义的导入目标netCDF::netcdf。

...

# ############################################################################## 
# Don't do this.
<s>find_file(CMAKE_PREFIX_PATH netCDFCxxConfig.cmake)</s>
# Instead, append the path to the config file using the 'list' command.
list(APPEND CMAKE_PREFIX_PATH "/path/to/installed/netcdf")

# Look for the 'netCDFCxx' package, since that is what the config file is called.
find_package (netCDFCxx REQUIRED) 

# Probably don't need this if we use the imported target below.
<s>include_directories(${NETCDF_INCLUDES})</s>

# set(SOURCE test.cpp player.cpp player.hpp)

# include_directories(include)

# Search all .cpp files 
file(GLOB_RECURSE SOURCE_FILES "*.cpp")

add_executable(test ${SOURCE_FILES})

# Link to the imported target 'netCDF::netcdf' here instead.
target_link_libraries(test 
                      PRIVATE
                          CONAN_PKG::boost
                          CONAN_PKG::eigen
                          netCDF::netcdf)
</pre>

为 NetCDF C++ 创建 CMake

Create CMake for NetCDF C++

c++

cmake

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