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首页 > 解决方案 > 处理错误 LNK2001：Python 扩展中未解析的外部符号 __imp__ExitWindowsEx@8

python - 处理错误 LNK2001：Python 扩展中未解析的外部符号 __imp__ExitWindowsEx@8

问题描述

我正在尝试构建一个 C 项目。我认为来源很好，但是我收到了这个错误：

错误 LNK2001：未解析的外部符号 __imp__ExitWindowsEx@8

或者对于完整的回溯：

C:\Users\Simon\Desktop\Learn>python setup.py build
running build
running build_ext
building 'sys_shutdown' extension
C:\Program Files (x86)\Microsoft Visual Studio\2017\WDExpress\VC\Tools\MSVC\14.14.26428\bin\HostX86\x86\cl.exe /c /nologo /Ox /W3 /GL /DNDEBUG /MT -IC:\Users\Simon\AppData\Local\Programs\Python\Python36-32\include -IC:\Users\Simon\AppData\Local\Programs\Python\Python36-32\include "-IC:\Program Files (x86)\Microsoft Visual Studio\2017\WDExpress\VC\Tools\MSVC\14.14.26428\include" "-IC:\Program Files (x86)\Windows Kits\NETFXSDK\4.6.1\include\um" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17134.0\ucrt" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17134.0\shared" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17134.0\um" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17134.0\winrt" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17134.0\cppwinrt" /Tcmain.c /Fobuild\temp.win32-3.6\Release\main.obj
main.c
C:\Program Files (x86)\Microsoft Visual Studio\2017\WDExpress\VC\Tools\MSVC\14.14.26428\bin\HostX86\x86\link.exe /nologo /INCREMENTAL:NO /LTCG /nodefaultlib:libucrt.lib ucrt.lib /DLL /MANIFEST:EMBED,ID=2 /MANIFESTUAC:NO /LIBPATH:C:\Users\Simon\AppData\Local\Programs\Python\Python36-32\libs /LIBPATH:C:\Users\Simon\AppData\Local\Programs\Python\Python36-32\PCbuild\win32 "/LIBPATH:C:\Program Files (x86)\Microsoft Visual Studio\2017\WDExpress\VC\Tools\MSVC\14.14.26428\lib\x86" "/LIBPATH:C:\Program Files (x86)\Windows Kits\NETFXSDK\4.6.1\lib\um\x86" "/LIBPATH:C:\Program Files (x86)\Windows Kits\10\lib\10.0.17134.0\ucrt\x86" "/LIBPATH:C:\Program Files (x86)\Windows Kits\10\lib\10.0.17134.0\um\x86" /EXPORT:PyInit_sys_shutdown build\temp.win32-3.6\Release\main.obj /OUT:build\lib.win32-3.6\sys_shutdown.cp36-win32.pyd /IMPLIB:build\temp.win32-3.6\Release\sys_shutdown.cp36-win32.lib
   Creating library build\temp.win32-3.6\Release\sys_shutdown.cp36-win32.lib and object build\temp.win32-3.6\Release\sys_shutdown.cp36-win32.exp
main.obj : error LNK2001: unresolved external symbol __imp__ExitWindowsEx@8
build\lib.win32-3.6\sys_shutdown.cp36-win32.pyd : fatal error LNK1120: 1 unresolved externals
error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\WDExpress\\VC\\Tools\\MSVC\\14.14.26428\\bin\\HostX86\\x86\\link.exe' failed with exit status 1120

我从这里计算出这__imp__ExitWindowsEx@8是由于找不到必要的运行时引起的。

不要使用#using 链接，而是使用链接器命令行链接。您可以通过将 user32.lib 添加到链接器命令来做到这一点

我在我的设置脚本中尝试了这个extra_objects：

import setup, Extension

module = Extension(
    "sys_shutdown", 
    sources = ["main.c"],
        extra_objects = ["C:\\Program Files (x86)\\Windows Kits\\10\Lib\\10.0.17134.0\\um\\arm64\\User32.Lib"]
)

setup (
    name = "sys_shutdown",
    version = "1.0",
    ext_modules = [module])

我的main.c文件（所以你知道为什么以及我需要链接到什么）：

#include <Python.h>
#include <Windows.h>


/* The functions that need to be created */

static PyObject * sys_shutdown(PyObject *self) {
    ExitWindowsEx(EWX_POWEROFF, SHTDN_REASON_MINOR_OTHER); // Shutdown
    return Py_BuildValue("");
}

static PyObject * sys_restart(PyObject *self) {
    ExitWindowsEx(EWX_REBOOT, SHTDN_REASON_MINOR_OTHER); // Restart
    return Py_BuildValue("");
}

static PyObject * sys_log_out(PyObject *self) {
    ExitWindowsEx(EWX_LOGOFF, SHTDN_REASON_MINOR_OTHER); // Log out
    return Py_BuildValue("");
}

static PyMethodDef allMethods[] = {
    {"sys_shutdown", (PyCFunction)sys_shutdown, METH_NOARGS, "Shuts down the device"},
    {"sys_restart", (PyCFunction)sys_restart, METH_NOARGS, "Restarts the device"},
    {"sys_log_out", (PyCFunction)sys_log_out, METH_NOARGS, "Closes all processes and logs out the user from the device"},
    {NULL, NULL, 0, NULL}
};

static struct PyModuleDef allModule = {
    PyModuleDef_HEAD_INIT,
    "System Functions",
    "sys_shutdown",
    -1,
    allMethods
};

PyMODINIT_FUNC PyInit_sys_shutdown(void) {
    return PyModule_Create(&allModule);
}

此扩展需要ExitWindowsEx()提供的功能user32.dll

我怎样才能链接user32.dll到我的扩展（或者如果我完全错过了情节，我怎样才能让它正确编译）？

标签： pythoncpython-3.xpython-c-api

解决方案

对，我找到了解决方案。已为系统运行时设置链接器路径。我所要做的就是链接运行时本身。这可以使用library设置脚本中的属性来完成：

from distutils.core import setup, Extension

module = Extension(
    "sys_shutdown", 
    sources = ["main.c"],
    libraries = ["user32"] # <-- Here it is
)

setup (
    name = "sys_shutdown",
    version = "1.0",
    ext_modules = [module])

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