无法执行Cython包装的Python代码 [英] Unable to execute Cython wrapped Python code

问题描述

我正在使用Cython导出python代码的C ++ API.该应用程序将在Ubuntu上执行.项目文件位于此处

I am exporting C++ API for python code using Cython. The application will be executed on Ubuntu. The project files are present here

我正在包装的函数，读取图像的文件名并显示图像. Show_Img.pyx文件如下所示

The function I am wrapping, reads the file name of the image and displays the image. The Show_Img.pyx file looks as follows

import cv2

cdef public void Print_image(char* name):
  img = cv2.imread(name)
  cv2.imshow("Image", img)
  while(True):
    if cv2.waitKey(1) & 0xFF == ord('q'):
      break

从Cython生成的c ++接口如下所示

The c++ interface generated from Cython looks as follows

__PYX_EXTERN_C DL_IMPORT(void) Print_image(char *);

头文件包含在我的algo.cpp中，该文件调用如下函数

The header file is included in my algo.cpp, which calls the function like below

#include<iostream>
#include<Python.h>
#include"Show_Img.h"
using namespace std;

int main(){
  char *name = "face.jpg"; 
  Py_Initialize();
  Print_image(name);
  Py_Finalize();
  return 0;
}

使用下面的命令，我还可以编译上面的代码并生成应用程序

With the command below, I can also compile the above code and also generate the application

g++ algo.cpp `pkg-config --libs --cflags python-2.7` `pkg-config --libs --cflags opencv` -L. -lShow_Img -o algo

还正确设置了库LD_LIBRARY_PATH的路径

应用程序执行后，出现错误Segmentation fault (core dumped)

Upon execution of the application, there is an error Segmentation fault (core dumped)

为什么我无法执行该应用程序，生成过程中是否有错误?或图书馆链接?

Why am I unable to execute the application, is there a mistake in the generation process? or Library linking?

推荐答案

要继续我的评论，您必须为该模块调用init函数:

To follow up on my comment, You have to call an init function for the module:

// ...
Py_Initialize();
initShow_Img(); // for Python3
   // (especially with the more modern 2 phase module initialization)
   //  the process is a little more complicated - see the documentation
Print_image(name);
Py_Finalize();
// ...

原因是这样设置模块，包括执行行import cv2.没有它，诸如访问模块全局变量(进入cv2)之类的东西将无法可靠地工作.这可能是分割错误的原因.

The reason being is that this sets up the module, include executing the line import cv2. Without it things like accessing the module globals (to get to cv2) won't reliably work. This a likely cause of the segmentation fault.

这在文档示例.

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