CMake include()与find_package()的默认搜索路径 [英] default search paths for CMake include() vs. find_package()

问题描述

我在Debian机器上安装了VTK6，并将其所有CMake文件放置在

I have VTK6 installed on my Debian machine and it places all its CMake files under

$ ls /usr/lib/cmake/vtk-6.3/
[...]
VTKConfig.cmake
vtkModuleAPI.cmake
[...]

当我这样做

find_package(VTK)

在另一个项目中，一切正常.但是，

in another project, it all works out fine. However,

include(vtkModuleAPI)

产生错误

include could not find load file:

  vtkModuleAPI

我一直给人的印象是 find_package()和 include 共享相同的搜索路径，特别是 CMAKE_MODULE_PATH .显然这是不正确的.

I had always been under the impression that find_package() and include share the same search paths, specifically CMAKE_MODULE_PATH. Apparently that's not correct.

请注意

SET(CMAKE_MODULE_PATH "/usr/lib/cmake/vtk-6.3")
include(vtkModuleAPI)

起作用.

还请注意，我正在使用CMake 3.5，因此不再有 FindVTK.cmake

Also note that I'm using CMake 3.5, so there no longer is a FindVTK.cmake as it used to be.

find_package()和 include()的默认搜索路径是什么?为什么找不到 vtkModuleAPI.cmake ?

What are the default search paths for find_package() and include()? Why is vtkModuleAPI.cmake not found?

推荐答案

模块模式试图找到 FindXXX.cmake 文件.在 CMAKE_MODULE_PATH 中列出的目录下以及在安装CMake的目录下搜索该文件.

1. Module mode tries to locate FindXXX.cmake file. The file is searched under directories listed in CMAKE_MODULE_PATH plus under directory where CMake is installed.

配置模式尝试找到 XXXConfig.cmake 文件.在 CMAKE_PREFIX_PATH 和其他一些特定于系统的变量中列出的目录下搜索该文件.(完整算法请参见文档，该文章开头链接.)

Config mode tries to locate XXXConfig.cmake file. The file is searched under directories listed in CMAKE_PREFIX_PATH and some other, system-specific variables. (Full algorithm see in the documentation, linked at the beginning of the post).

命令 include 仅在 CMAKE_MODULE_PATH 和特殊的CMake模块目录.

Command include searches modules only under directories in CMAKE_MODULE_PATH and special CMake module directory.

如您所见，在模块模式中的命令 include 和命令 find_package 使用相似的搜索路径.但是在您的情况下，只能在 find_package 的 config模式中搜索 VTKConfig.cmake ，该模式使用完全不同的搜索算法.

As you can see, command include and command find_package in module mode uses similar search paths. But in your case, VTKConfig.cmake can be searched only in config mode of find_package, which uses completely different search algorithm.

对于VTK，CMake附带了 FindVTK.cmake 文件，该文件在您调用 find_package(VTK)时使用.但是在内部，此脚本使用了 find_package(VTK QUIET NO_MODULE).

In case of VTK, CMake has shipped FindVTK.cmake file, which is used when you call find_package(VTK). But inside, this script uses find_package(VTK QUIET NO_MODULE).

如果此调用找到文件/usr/lib/cmake/vtk-6.3/VTKConfig.cmake ，它将执行此脚本，并且该脚本包括 vtkModuleAPI.cmake 一个

If this call locates file /usr/lib/cmake/vtk-6.3/VTKConfig.cmake, it executes this script, and the script includes vtkModuleAPI.cmake one.

如果您的 VTKConfig.cmake 不在CMake中，您可以通过将 VTK_DIR 变量设置为/usr/lib/cmake/vtk-6.3来提供帮助./.

If your VTKConfig.cmake is not located by CMake, you may help it by setting VTK_DIR variable to /usr/lib/cmake/vtk-6.3/.

[从CMake-3.1开始， FindVTK.cmake 不再随CMake一起提供，因此 find_package(VTK)立即尝试查找 VTKConfig.cmake ].

[Starting with CMake-3.1, FindVTK.cmake is no longer shipped with CMake, so find_package(VTK) immediately tries to locate VTKConfig.cmake].

无论如何，目录/usr/lib/cmake/vtk-6.3/中的模块不应直接包含:此目录为 private 用于VTK.

In any case, modules in directory /usr/lib/cmake/vtk-6.3/ shouldn't be included directly: this directory is private for VTK.

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