C++ 中带有 MinGW 的嵌入式 python3.6 链接失败

Question

尝试在Win10 64位系统上将python3.6嵌入C++。 Python 由python-3.6.1-amd64.exe 安装。 CMakeList.txt 如下所示

cmake_minimum_required(VERSION 3.8)
project(EmbedPython)

set(CMAKE_CXX_STANDARD 11)

set(SOURCE_FILES main.cpp)
find_package(PythonLibs REQUIRED)
include_directories(${PYTHON_INCLUDE_DIRS})
add_executable(EmbedPython ${SOURCE_FILES} ${PYTHON_INCLUDE_DIRS})
target_link_libraries(EmbedPython ${PYTHON_LIBRARIES})

CMake 找到了 Python 包。

PYTHON_INCLUDE_DIR C:/Program Files (x86)/Python36/include
PYTHON_LIBRARY C:/Program Files (x86)/Python36/libs/python36.lib

Find a comment on github说的是API问题。

# used to embed python script
find_package(PythonLibs 2.7 REQUIRED) # this has to be 2.7 because the 3.0 API requires argv to be wchar_t** rather than the default char**
include_directories(${PYTHON_INCLUDE_DIRS})
target_link_libraries( assignment ${PYTHON_LIBRARIES})

下面的错误是我所面临的。

[ 50%] Building CXX object CMakeFiles/EmbedPython.dir/main.cpp.obj
[100%] Linking CXX executable EmbedPython.exe
CMakeFiles\EmbedPython.dir/objects.a(main.cpp.obj): In function `main':
D:/Projects/EmbedPython/main.cpp:16: undefined reference to `_imp__Py_Initialize'
D:/Projects/EmbedPython/main.cpp:17: undefined reference to `_imp__PyUnicode_DecodeFSDefault'
D:/Projects/EmbedPython/main.cpp:20: undefined reference to `_imp__PyImport_Import'
D:/Projects/EmbedPython/main.cpp:24: undefined reference to `_imp__PyObject_GetAttrString'
D:/Projects/EmbedPython/main.cpp:27: undefined reference to `_imp__PyCallable_Check'
D:/Projects/EmbedPython/main.cpp:28: undefined reference to `_imp__PyTuple_New'
D:/Projects/EmbedPython/main.cpp:30: undefined reference to `_imp__PyLong_FromLong'
D:/Projects/EmbedPython/main.cpp:38: undefined reference to `_imp__PyTuple_SetItem'
D:/Projects/EmbedPython/main.cpp:40: undefined reference to `_imp__PyObject_CallObject'
D:/Projects/EmbedPython/main.cpp:43: undefined reference to `_imp__PyLong_AsLong'
D:/Projects/EmbedPython/main.cpp:49: undefined reference to `_imp__PyErr_Print'
D:/Projects/EmbedPython/main.cpp:55: undefined reference to `_imp__PyErr_Occurred'
D:/Projects/EmbedPython/main.cpp:56: undefined reference to `_imp__PyErr_Print'
D:/Projects/EmbedPython/main.cpp:63: undefined reference to `_imp__PyErr_Print'
D:/Projects/EmbedPython/main.cpp:67: undefined reference to `_imp__Py_FinalizeEx'
collect2.exe: error: ld returned 1 exit status
mingw32-make.exe[3]: *** [EmbedPython.exe] Error 1
mingw32-make.exe[2]: *** [CMakeFiles/EmbedPython.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles/EmbedPython.dir/rule] Error 2
mingw32-make.exe: *** [EmbedPython] Error 2
CMakeFiles\EmbedPython.dir\build.make:96: recipe for target 'EmbedPython.exe' failed
CMakeFiles\Makefile2:66: recipe for target 'CMakeFiles/EmbedPython.dir/all' failed
CMakeFiles\Makefile2:78: recipe for target 'CMakeFiles/EmbedPython.dir/rule' failed
Makefile:117: recipe for target 'EmbedPython' failed

不确定如何使项目运行。任何帮助将不胜感激。

编辑： 来自make VERBOSE=1的结果

D:\Projects\EmbedPython\cmake-build-debug>make VERBOSE=1
"C:\Program Files\JetBrains\CLion 172.2273.4\bin\cmake\bin\cmake.exe" -HD:\Projects\EmbedPython -BD:\Projects\EmbedPython\cmake-build-debug --check-build-system CMakeFiles\Makefile.cmake 0
"C:\Program Files\JetBrains\CLion 172.2273.4\bin\cmake\bin\cmake.exe" -E cmake_progress_start D:\Projects\EmbedPython\cmake-build-debug\CMakeFiles D:\Projects\EmbedPython\cmake-build-debug\CMakeFiles\progress.marks
make -f CMakeFiles\Makefile2 all
make[1]: Entering directory 'D:/Projects/EmbedPython/cmake-build-debug'
make -f CMakeFiles\EmbedPython.dir\build.make CMakeFiles/EmbedPython.dir/depend
make[2]: Entering directory 'D:/Projects/EmbedPython/cmake-build-debug'
"C:\Program Files\JetBrains\CLion 172.2273.4\bin\cmake\bin\cmake.exe" -E cmake_depends "MinGW Makefiles" D:\Projects\EmbedPython D:\Projects\EmbedPython D:\Projects\EmbedPython\cmake-build-debug D:\Projects\EmbedPython\cmake-build-debug D:\Projects\EmbedPython\cmake-build-debug\CMakeFiles\EmbedPython.dir\DependInfo.cmake --color=
make[2]: Leaving directory 'D:/Projects/EmbedPython/cmake-build-debug'
make -f CMakeFiles\EmbedPython.dir\build.make CMakeFiles/EmbedPython.dir/build
make[2]: Entering directory 'D:/Projects/EmbedPython/cmake-build-debug'
[ 50%] Linking CXX executable EmbedPython.exe
"C:\Program Files\JetBrains\CLion 172.2273.4\bin\cmake\bin\cmake.exe" -E cmake_link_script CMakeFiles\EmbedPython.dir\link.txt --verbose=1
"C:\Program Files\JetBrains\CLion 172.2273.4\bin\cmake\bin\cmake.exe" -E remove -f CMakeFiles\EmbedPython.dir/objects.a
C:\PROGRA~2\MINGW-~1\I686-6~1.0-P\mingw32\bin\ar.exe cr CMakeFiles\EmbedPython.dir/objects.a @CMakeFiles\EmbedPython.dir\objects1.rsp
C:\PROGRA~2\MINGW-~1\I686-6~1.0-P\mingw32\bin\G__~1.EXE -g   -Wl,--whole-archive CMakeFiles\EmbedPython.dir/objects.a -Wl,--no-whole-archive  -o EmbedPython.exe -Wl,--out-implib,libEmbedPython.dll.a -Wl,--major-image-version,0,--minor-image-version,0 @CMakeFiles\EmbedPython.dir\linklibs.rsp
CMakeFiles\EmbedPython.dir/objects.a(main.cpp.obj): In function `main':
D:/Projects/EmbedPython/main.cpp:16: undefined reference to `_imp__Py_Initialize'
D:/Projects/EmbedPython/main.cpp:17: undefined reference to `_imp__PyUnicode_DecodeFSDefault'
D:/Projects/EmbedPython/main.cpp:20: undefined reference to `_imp__PyImport_Import'
D:/Projects/EmbedPython/main.cpp:24: undefined reference to `_imp__PyObject_GetAttrString'
D:/Projects/EmbedPython/main.cpp:27: undefined reference to `_imp__PyCallable_Check'
D:/Projects/EmbedPython/main.cpp:28: undefined reference to `_imp__PyTuple_New'
D:/Projects/EmbedPython/main.cpp:30: undefined reference to `_imp__PyLong_FromLong'
D:/Projects/EmbedPython/main.cpp:38: undefined reference to `_imp__PyTuple_SetItem'
D:/Projects/EmbedPython/main.cpp:40: undefined reference to `_imp__PyObject_CallObject'
D:/Projects/EmbedPython/main.cpp:43: undefined reference to `_imp__PyLong_AsLong'
D:/Projects/EmbedPython/main.cpp:49: undefined reference to `_imp__PyErr_Print'
D:/Projects/EmbedPython/main.cpp:55: undefined reference to `_imp__PyErr_Occurred'
D:/Projects/EmbedPython/main.cpp:56: undefined reference to `_imp__PyErr_Print'
D:/Projects/EmbedPython/main.cpp:63: undefined reference to `_imp__PyErr_Print'
D:/Projects/EmbedPython/main.cpp:67: undefined reference to `_imp__Py_FinalizeEx'
collect2.exe: error: ld returned 1 exit status
CMakeFiles\EmbedPython.dir\build.make:97: recipe for target 'EmbedPython.exe' failed
make[2]: *** [EmbedPython.exe] Error 1
make[2]: Leaving directory 'D:/Projects/EmbedPython/cmake-build-debug'
CMakeFiles\Makefile2:66: recipe for target 'CMakeFiles/EmbedPython.dir/all' failed
make[1]: *** [CMakeFiles/EmbedPython.dir/all] Error 2
make[1]: Leaving directory 'D:/Projects/EmbedPython/cmake-build-debug'
Makefile:82: recipe for target 'all' failed
make: *** [all] Error 2

Answer 1

我在尝试从 Python 手册构建 example 时遇到了完全相同的问题。

我的系统是 64 位 Windows，安装的 Python 是 64 位 3.7（来自 Anaconda3），编译器是 32 位 MinGW 5.3.0（来自 Qt 5.11）。

对我有用的最简单的解决方案如下：

• 从this页面下载Windows x86 embeddable zip file。
• 将该存档的内容放入您正在构建的项目内的文件夹中。
• 不要不要安装该存档中的任何内容，也不要不要将其放在系统 PATH 中。
• 将上述文件夹添加到gcc库搜索路径，使用：-L"path/to/folder/"
• 使用-l"python37" 将python 库添加到链接器（将37 替换为您下载的任何版本）
• 如上所述here（这很难找到！），添加一个定义，使用-DPy_BUILD_CORE_BUILTIN=1（也可以在#include之前写#define DPy_BUILD_CORE_BUILTIN 1-ing Python header，虽然我不推荐）
• 使用-I"path/to/include" 提供Python 标头的路径。我使用了来自 Anaconda 的那个，例如-I"c:/Users/user/Anaconda3/include/"。任何已安装的标头都可以，只需确保其来自相同版本（也可能使用旧版本的标头，但这可能会导致时空连续体破裂）
• 确保 #include <Python.h> 在任何其他包含之前，如手册中所述。

作为旁注，MinGW 链接器 (ld) 多年来一直是完美的内容，只要你给它“dll”文件。如果您没有 lib 并且只执行动态链接，则不需要“lib”或“a”。这就是为什么我刚刚告诉链接器使用python37。

实际上是smart enough 来查找python37.lib、python37.dll 和libpython37.a 之类的文件。

另请注意，“可嵌入 zip”只是嵌入 Python 所需的最低限度。

作为最后的评论，与here 所述相反，从 GCC 链接到使用 MSVS 编译的库（反之亦然）没有任何问题，只要该库使用普通 C 接口，因为该接口几乎是任何给定平台的不同编译器兼容的唯一接口。

这几乎就是 Python 使用 C 接口（仅此而已，甚至是 C++）来扩展和嵌入的确切原因 - 以允许以任何语言，使用任何工具集，与 Python 交互。

Answer 2

我遇到了同样的问题。

问题可能是因为使用了 32 位 MinGW 和 64 位 Python。你应该安装 32 位版本的 python

希望对你有用:-)