CMAKE 找不到 PythonLibs（缺少：PYTHON_INCLUDE_DIRS）答案

【问题标题】：CMAKE Could NOT find PythonLibs (missing: PYTHON_INCLUDE_DIRS)CMAKE 找不到 PythonLibs（缺少：PYTHON_INCLUDE_DIRS）
【发布时间】：2021-02-05 17:09:52
【问题描述】：

我正在尝试在我们学校的项目中运行cmake，CMakeList.txt看起来如下：

cmake_minimum_required(VERSION 3.0)
project(nagata)
FIND_PACKAGE( OpenMP )
if(OPENMP_FOUND)
message("OPENMP FOUND")
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
endif()

set(CMAKE_C_COMPILER clang-omp CACHE STRING "C compiler" FORCE)
set(CMAKE_CXX_COMPILER clang-omp++ CACHE STRING "C++ compiler" FORCE)

FIND_PACKAGE( pybind11 REQUIRED )

FIND_PACKAGE(PythonInterp 3)
FIND_PACKAGE(PythonLibs   3)

IF( PYTHONINTERP_FOUND AND PYTHONLIBS_FOUND AND PYBIND11_FOUND )
  INCLUDE_DIRECTORIES(
    ${PYTHON_INCLUDE_DIRS}
    ${PYBIND11_INCLUDE_DIRS}
  )
  ENDIF()
INCLUDE_DIRECTORIES("/usr/include/python3.7m")

add_library(pynagata SHARED pythonlib.cpp)
 # The library must not have any prefix and should be located in
  # a subfolder that includes the package name. The setup will be
  # more complicated otherwise.
  SET_TARGET_PROPERTIES( pynagata
    PROPERTIES
      PREFIX ""
      LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/pynagata"
  )

add_executable(nagata main.cpp)
install(TARGETS nagata RUNTIME DESTINATION bin)

当我在 build 目录中运行 cmake .. 时，我得到的输出看起来几乎没问题：

-- The C compiler identification is Clang 11.0.0
-- The CXX compiler identification is Clang 11.0.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/local/opt/llvm/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/local/opt/llvm/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found OpenMP_C: -fopenmp=libomp (found version "5.0") 
-- Found OpenMP_CXX: -fopenmp=libomp (found version "5.0") 
-- Found OpenMP: TRUE (found version "5.0")  
OPENMP FOUND
-- Found PythonInterp: /usr/local/bin/python3.8 (found version "3.8.6") 
-- Found PythonLibs: /usr/local/opt/python@3.8/Frameworks/Python.framework/Versions/3.8/lib/libpython3.8.dylib
-- Performing Test HAS_CPP14_FLAG
-- Performing Test HAS_CPP14_FLAG - Success
-- Found PythonInterp: /usr/local/bin/python3.8 (found suitable version "3.8.6", minimum required is "3") 
-- Could NOT find PythonLibs (missing: PYTHON_INCLUDE_DIRS) (Required is at least version "3")
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/.../build

除了-- Could NOT find PythonLibs (missing: PYTHON_INCLUDE_DIRS) (Required is at least version "3") 这行我觉得很奇怪，因为在它真正找到它之前只有几行：-- Found PythonLibs: /usr/local/opt/python@3.8/Frameworks/Python.framework/Versions/3.8/lib/libpython3.8.dylib。我试图设置一个环境变量PYTHON_INCLUDE_DIRS="/usr/local/opt/python@3.8/Frameworks/Python.framework/Versions/3.8/lib/libpython3.8.dylib"，它与上一行的路径完全相同。不过，我得到了这个错误。

我怎样才能让它找到PythonLibs？我真的不明白为什么 env 变量不起作用。我也很乐意提供更多信息 - 我只是不知道是什么。

我正在使用：

CLT：12.0.0.0.1.1599194153
Xcode：12.0.1
macOS Catalina 版本。 10.15.7
Clang：12.0 build 1200

PS：当我之后尝试运行make 时，我得到fatal error: 'string' file not found #include <string>，这可能与此问题有关...

【问题讨论】：

您尝试更改FIND_PACKAGE(PythonInterp 3) 行吗？也许删除3？
我刚试过，但没有帮助 - 相同的消息只不需要版本 3。

标签： python c++ cmake macos-catalina

【解决方案1】：

看来我把旗子的名字弄错了。使用以下标志调用 cmake 为我解决了这个问题：

cmake -DPYTHON_LIBRARY=$(python3-config --prefix)/lib/libpython3.8.dylib -DPYTHON_INCLUDE_DIR=$(python3-config --prefix)/include/python3.8 ..

它现在成功找到了 PythonLibs。

【讨论】：