c++ - 构建 Python C++ 扩展在重载函数上失败

Question

我想用 C++ 编写一个 Python 模块并尝试使用 distutils 编译它，但是当我尝试使用重载函数时它突然给我一个编译错误。我该如何应对？

这是一个简单的模块，根据official manual.编写的

该模块由 3 个文件组成:pymega.cpp(Python 解释器的模块接口(interface))、payload.h 和 payload.cpp(这里应该是“有效载荷”)。

pymega.cpp

//pymega.cpp
#include <Python.h>

#include <iostream>
using namespace std;

#include "payload.h"

static PyObject* test(PyObject* self, PyObject* args)
{
  cout << "Running test method!" << endl;
  cout << "^__^" << endl;

  PyMega::uber_function(7, 40);
  return Py_None;
}

//Module methods declatarion
static PyMethodDef Methods[] = {
    {"test",  test, METH_VARARGS, "Hell yeah!!"},
    {NULL, NULL, 0, NULL}        /* Sentinel */
};

static struct PyModuleDef pymega = {
   PyModuleDef_HEAD_INIT,
   "pymega",   /* name of module */
   NULL, /* module documentation, may be NULL */
   -1,       /* size of per-interpreter state of the module,
                or -1 if the module keeps state in global variables. */
   Methods
};

// Module nitialization
PyMODINIT_FUNC PyInit_pymega(void)
{
  cout << "Initializing PyMega..." << endl;
  PyObject *m;

  m = PyModule_Create(&pymega);
  if (m == NULL)
  {
    cout << "PyMega init failed" << endl;
    return NULL;
  }

  return m;
}

有效载荷.h

//payload.h
#ifndef PAYLOAD_H_
#define PAYLOAD_H_

#include <Python.h>

#include <iostream>
using namespace std;

namespace PyMega {

  void uber_function(unsigned int arg1);
  void uber_function(unsigned int arg1, unsigned int arg2);

} // PyMega


#endif  // PAYLOAD_H_

payload.cpp

//payload.cpp
#include "payload.h"

#include <iostream>
using namespace std;

using namespace PyMega;

void uber_function(unsigned int arg1)
{
  cout << "uber_function " << arg1 << endl;
}

void uber_function(unsigned int arg1, unsigned int arg2)
{
  cout << "uber_function " << arg1 << " " << arg2 << endl;
  uber_function(arg1);
}

此外，这是 setup.py(我的安装脚本)。

from distutils.core import setup, Extension

module1 = Extension('pymega',
                    sources=['pymega.cpp', "payload.cpp"],
                    language="c++")

setup (name='PackageName',
       version='1.0',
       description='This is a demo package',
       ext_modules=[module1])

当我尝试运行 setup.py build 时，它给我以下错误日志:

running build
running build_ext
building 'pymega' extension
x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes 
-g -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security 
-D_FORTIFY_SOURCE=2 -fPIC -I/usr/include/python3.4m -c pymega.cpp -o build/temp.
linux-x86_64-3.4/pymega.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC 
but not for C++ [enabled by default]
x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes 
-g -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security 
-D_FORTIFY_SOURCE=2 -fPIC -I/usr/include/python3.4m -c payload.cpp -o build/temp
.linux-x86_64-3.4/payload.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC 
but not for C++ [enabled by default]
payload.cpp: In function ‘void uber_function(unsigned int, unsigned int)’:
payload.cpp:16:21: error: call of overloaded ‘uber_function(unsigned int&)’ is a
mbiguous
   uber_function(arg1);
                     ^
payload.cpp:16:21: note: candidates are:
payload.cpp:8:6: note: void uber_function(unsigned int)
 void uber_function(unsigned int arg1)
      ^
In file included from payload.cpp:1:0:
payload.h:11:8: note: void PyMega::uber_function(unsigned int)
   void uber_function(unsigned int arg1);
        ^
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

Answer 1

您已经在 ::PyMega 命名空间中声明了 void uber_function(int)，然后继续定义 void uber_function(int)在 :: 命名空间中。这是来自不同 namespace 的两个不同函数，具有相同的名称和签名，这会导致冲突。可能不是您想要的。

要定义 ::PyMega::uber_function 你必须说

namespace PyMega
{
   void uber_function(int) {
       ....
   }
}