使用 luarocks 安装 fbtorch 时，Cmake 无法识别 FOLLY_LIBRARIES 的缓存条目

Question

我正在尝试在 Linux 上安装 fbtorch。但是，当我尝试运行 luarocks install fbtorch 时，出现以下错误。

cmake -E make_directory build && cd build && cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH="/home/user/torch/install/bin/.." -DCMAKE_INSTALL_PREFIX="/home/user/torch/install/lib/luarocks/rocks/fbtorch/scm-1"

fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found Torch7 in /home/user/torch/install
CMake Error at /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  REQUIRED_ARGS (missing: FOLLY_INCLUDE_DIR FOLLY_LIBRARIES)
Call Stack (most recent call first):
  /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  cmake/FindFolly.cmake:23 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:12 (FIND_PACKAGE)


-- Configuring incomplete, errors occurred!
See also "/tmp/luarocks_fbtorch-scm-1-4920/fbtorch/build/CMakeFiles/CMakeOutput.log".

现在，为了修复 REQUIRED_ARGS (missing: FOLLY_INCLUDE_DIR FOLLY_LIBRARIES)，我将 cmake 命令更改为：

cmake -E make_directory build && cd build && cmake .. -DFOLLY_LIBRARIES="/home/user/local/lib" -DFOLLY_INCLUDE_DIR="/home/user/local/include" -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH="$(LUA_BINDIR)/.." -DCMAKE_INSTALL_PREFIX="$(PREFIX)"

请注意，我已经在适当的目录中编译并安装了folly /home/user/local/

这修复了FOLLY_INCLUDE_DIR 错误，但它仍然显示FOLLY_LIBRARIES 的错误，如下所示：

CMake Error at /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  REQUIRED_ARGS (missing: FOLLY_LIBRARIES)
Call Stack (most recent call first):
  /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  cmake/FindFolly.cmake:23 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:12 (FIND_PACKAGE)

我在这里缺少什么？为什么 cmake 可以识别 FOLLY_INCLUDE_DIR 的缓存条目，但不能识别 FOLLY_LIBRARIES？

Answer 1

find_package() 调用中“错过”列表中列出的变量不需要是 CACHE 变量。因此，设置同名缓存变量可能无法解决问题。

如果搜索到的包实际安装到非标准位置，与其盲目设置“缺失”变量，不如提示关于该位置的“查找”脚本.

许多“查找”脚本在其代码的开头描述了可能的参数化方式。除此之外，还有常用方法可以提示“查找”脚本关于包的实际位置；这些方式适用于大多数脚本。例如。您可以将包的安装位置添加到 CMAKE_PREFIX_PATH 变量中（参见that question）。

Answer 2

如果您查看FindFolly.cmake，您可以看到这条线 -

SET(FOLLY_LIBRARIES ${FOLLY_LIBRARY})

这意味着正在设置FOLLY_LIBRARIES，但它需要FOLLY_LIBRARY。

所以在你的命令行中将-DFOLLY_LIBRARIES 更改为-DFOLLY_LIBRARY