使用CMake链接到犰狳库 [英] Linking to Armadillo libraries with CMake

问题描述

我在Windows 8上安装MLPack。
我用CMakeLists.txt文件配置：

I am trying to install MLPack on windows 8. I configure the CMakeLists.txt file with:

set(ARMADILLO_LIBRARY "C:\\Program Files (x86)\\armadillo\\lib")
set(ARMADILLO_INCLUDE_DIR "C:\\Program Files (x86)\\armadillo\\include")

然后当我运行CMake时，我有一系列的警告这些：

Then when I ran CMake I had a whole series of warning like these ones:

WARNING: Target "mlpack" requests linking to directory "C:\Program Files (x86)\armadillo\lib".  Targets may link only to libraries.  CMake is dropping the item.

在\ mlpack-1.0.4 \src\mlpack目录中，我找到了另一个CMakeLists文件：

In \mlpack-1.0.4\src\mlpack directory I found another CMakeLists file with:

target_link_libraries(mlpack
  ${ARMADILLO_LIBRARIES}
  ${Boost_LIBRARIES}
  ${LIBXML2_LIBRARIES}
)

我不知道这是不是一个好主意） ：

that I changed to (not sure if that was a good idea):

target_link_libraries(mlpack
  ${Boost_LIBRARIES}
)
link_directories(mlpack
  ${ARMADILLO_LIBRARIES}
  ${LIBXML2_LIBRARIES}
)

似乎运行顺利：

-- Found Armadillo: C:\Program Files (x86)\armadillo\lib (found suitable version "3.800.2", minimum required is "2.4.2")
-- Found LibXml2: C:\cpp\libraries\libxml2-2.7.8.win32\lib (found suitable version "2.7.8", minimum required is "2.6.0")
-- Boost version: 1.53.0
-- Found the following Boost libraries:
--   program_options
--   unit_test_framework
-- Boost version: 1.53.0
-- Found the following Boost libraries:
--   random
-- Could NOT find Doxygen (missing:  DOXYGEN_EXECUTABLE)
-- Configuring done
-- Generating done
-- Build files have been written to: C:/cpp/libraries/mlpack-1.0.4

但是现在当我运行make我有很多这样的错误：

but now when running make I have tons of such errors :

Linking CXX executable ..\..\..\..\gmm.exe
CMakeFiles\gmm.dir/objects.a(gmm_main.cpp.obj):gmm_main.cpp:(.text+0xb9): undefined reference to `wrapper_dgemv_'
CMakeFiles\gmm.dir/objects.a(gmm_main.cpp.obj):gmm_main.cpp:(.text$_ZN4arma6auxlib10det_lapackIdEET_RKNS_3MatIS2_EEb[__ZN4arma6auxlib10det_lapackIdEET_RKNS_3MatIS2_EEb]+0x115): undefined reference to `wrapper_dgetrf_'

后调查似乎与Armadillo 。

which after investigation seems to be related to Armadillo.

任何想法发生了什么？我想我应该使用target_link_libraries为犰狳，但我不知道如何。

Any idea what is happening ? I guess I should use target_link_libraries for Armadillo but I am not sure how.

推荐答案

这个问题希望很容易解决。当你这样做...

The issue is hopefully pretty easy to resolve. When you do this...

set(ARMADILLO_LIBRARY "C:\\Program Files (x86)\\armadillo\\lib")
set(ARMADILLO_INCLUDE_DIR "C:\\Program Files (x86)\\armadillo\\include")

它期望必须做的工作找到这些路径。然而，当 find_package 执行工作时，变量 ARMADILLO_LIBRARY 设置为库本身的路径 - 而不是路径

you're effectively short-circuiting the find_package(Armadillo 2.4.2 REQUIRED) call, since it expects to have to do the work to find these paths. However, when find_package does the work, the variable ARMADILLO_LIBRARY gets set to the path to the library itself - not the path to the lib's directory.

因此，问题归结为将 ARMADILLO_LIBRARY 设置为lib目录的路径，而不是lib本身。这最终会导致链接器错误，因为目标 gmm （在src \mlpack\methods\gmm\CMakeLists.txt中添加）链接到 mlpack ，并且 mlpack 已设置为链接到 $ {ARMADILLO_LIBRARIES}

So the problem boils down to setting ARMADILLO_LIBRARY to the path to the lib's directory rather than the lib itself. This ultimately yields a linker error since the target gmm (added in src\mlpack\methods\gmm\CMakeLists.txt) links to mlpack, and mlpack has been set to link to ${ARMADILLO_LIBRARIES}, which isn't set correctly.

结果是 find_package（Armadillo ...）已经检入$ ENV {ProgramFiles} / Armadillo / lib和$ ENV {ProgramFiles} / Armadillo / include这些解析为C：\\Program Files（x86）\\armadillo\\lib和C： \\\Program Files（x86）\\armadillo\\include。

It turns out that find_package(Armadillo ...) already checks in "$ENV{ProgramFiles}/Armadillo/lib" and "$ENV{ProgramFiles}/Armadillo/include", and I expect these resolve to "C:\\Program Files (x86)\\armadillo\\lib" and "C:\\Program Files (x86)\\armadillo\\include" on your machine.

您应该删除 ARMADILLO_LIBRARY 和 ARMADILLO_INCLUDE_DIR 的行并还原您在src\mlpack\CMakeLists.txt中的更改（使用 link_directories 通常是一个坏主意。）

So to fix this, you should delete the lines setting ARMADILLO_LIBRARY and ARMADILLO_INCLUDE_DIR, and revert your change in src\mlpack\CMakeLists.txt (using link_directories is generally a bad idea anyway).

应该在重新运行CMake之前至少删除CMakeCache.txt（在构建树的根目录中），甚至删除整个构建树，以避免使用先前失败尝试中使用的不良缓存值的可能性。

After making these changes, you should delete at least your CMakeCache.txt (in the root of your build tree), or even your entire build tree before re-running CMake to avoid the possibility of using bad cached values from previous failed attempts.

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