在CMD

Question

我试图将列表作为输入。我也用Google搜索了。我在命令提示符下构建并安装了我的C-extension模块。我能够导入模块，但它确实显示了很少的警告。它告诉我的是......

在CMD

D:\Python\c\summa>py setup.py build
running build
running build_ext
building 'saiyanism' extension
C:\Program Files\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.2612
8\bin\HostX86\x86\cl.exe /c /nologo /Ox /W3 /GL /DNDEBUG /MD -IE:\python\include
 -IE:\python\include "-IC:\Program Files\Microsoft Visual Studio\2017\Community\
VC\Tools\MSVC\14.13.26128\include" "-IC:\Program Files\Windows Kits\NETFXSDK\4.6
.1\include\um" "-IC:\Program Files\Windows Kits\10\include\10.0.16299.0\ucrt" "-
IC:\Program Files\Windows Kits\10\include\10.0.16299.0\shared" "-IC:\Program Fil
es\Windows Kits\10\include\10.0.16299.0\um" "-IC:\Program Files\Windows Kits\10\
include\10.0.16299.0\winrt" "-IC:\Program Files\Windows Kits\10\include\10.0.162
99.0\cppwinrt" /TcH.c /Fobuild\temp.win32-3.6\Release\H.obj
H.c
H.c(63): warning C4133: 'function': incompatible types - from 'PyObject *' to 'c
onst char *const '
H.c(117): warning C4113: 'PyObject *(__cdecl *)(PyObject *)' differs in paramete
r lists from 'PyCFunction'
C:\Program Files\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.2612
8\bin\HostX86\x86\link.exe /nologo /INCREMENTAL:NO /LTCG /DLL /MANIFEST:EMBED,ID
=2 /MANIFESTUAC:NO /LIBPATH:E:\python\libs /LIBPATH:E:\python\PCbuild\win32 "/LI
BPATH:C:\Program Files\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.1
3.26128\lib\x86" "/LIBPATH:C:\Program Files\Windows Kits\NETFXSDK\4.6.1\lib\um\x
86" "/LIBPATH:C:\Program Files\Windows Kits\10\lib\10.0.16299.0\ucrt\x86" "/LIBP
ATH:C:\Program Files\Windows Kits\10\lib\10.0.16299.0\um\x86" /EXPORT:PyInit_sai
yanism build\temp.win32-3.6\Release\H.obj /OUT:build\lib.win32-3.6\saiyanism.cp3
6-win32.pyd /IMPLIB:build\temp.win32-3.6\Release\saiyanism.cp36-win32.lib
   Creating library build\temp.win32-3.6\Release\saiyanism.cp36-win32.lib and ob
ject build\temp.win32-3.6\Release\saiyanism.cp36-win32.exp
Generating code
d:\python\c\summa\h.c(112) : warning C4715: 'sumlist': not all control paths ret
urn a value
Finished generating code

D:\Python\c\summa>

这是我的c模块....

H.C

#include "Python.h"
static PyObject* saiyanism(PyObject* self,PyObject* args)
    {
    const char* saiyajin;
    if(!(PyArg_ParseTuple(args,"s",&saiyajin))) return NULL;
    printf("Hello,%s.Glad to see a saiyan.\n",saiyajin);
    Py_RETURN_NONE;

    }
static PyObject* UI(PyObject* self)  //,PyObject* args)
{/*code here works properly*/
Py_RETURN_NONE;
}

static PyObject* set_all(PyObject* self,PyObject *target)//PyLong_FromLong(PyObject *item))
{
    /*some code and this too works*/
    Py_RETURN_NONE;
}

static PyObject* sumlist(PyObject* self,PyObject *args)
{
PyObject *pList;
PyObject *pItem;
Py_ssize_t n;
int i;

if (!PyArg_ParseTuple(args, "O!", &PyList_Type, &pList)) {
    PyErr_SetString(PyExc_TypeError, "parameter must be a list.");
    return NULL;
}

n = PyList_Size(pList);

for (i=0; i<n; i++) {
    pItem = PyList_GetItem(pList, i);
    if(!PyLong_Check(pItem)) {
        PyErr_SetString(PyExc_TypeError, "list items must be integers.");
        printf("%ld",PyLong_AsLong(pItem));
        Py_RETURN_NONE;
    }
}
}

static PyMethodDef sups[]=
{
    {"saiyanism",saiyanism,METH_VARARGS,""},
    {"UI",UI,METH_NOARGS,""},
    {"set_all",set_all,METH_VARARGS,""},
    {"sumlist",sumlist,METH_VARARGS,""},
    {NULL,NULL,0,NULL}
};

static struct PyModuleDef saiyanismdef={
    PyModuleDef_HEAD_INIT,
    "saiyanism",
    "sad",
    -1,
    sups
};

PyMODINIT_FUNC PyInit_saiyanism(void){
Py_Initialize();
return PyModule_Create(&saiyanismdef);
}

问题是

当我尝试导入并使用python列表运行我的sumlist函数作为参数Python立即停止。

以下是image

我刚开始学习这个，所以如果我的课程有错误，请指出。

我应该以不同的方式传递争论吗？我哪里错了？

Answer 1

我可以在sumlist中看到至少两个错误：

在代码中
```
if(!PyLong_Check(pItem)) {
    PyErr_SetString(PyExc_TypeError, "list items must be integers.");
    printf("%ld",PyLong_AsLong(pItem));
    Py_RETURN_NONE;
}
```
返回None（Python对象）而不是C NULL指针，用于指示错误。您还尝试使用pItem打印PyLong_AsLong - 您对[{1}}了解的一件事就是它不是pItem ！
（导致您出现问题的主要错误）当long结束而没有任何错误时会发生什么？你没有返回任何东西，Python希望你返回sumlist。这就是警告告诉你的事情：

警告C4715：'sumlist'：并非所有控制路径都返回值

这里的快速修复是将PyObject*添加到函数的末尾，以将Py_RETURN_NONE对象返回给Python。但是，您可能想要做一些更有用的事情....

Python3 c api - python停止工作

在CMD

这是我的c模块....

H.C

问题是

1 个答案: