使用Cython和distutilis方法从Python调用C代码

我正在尝试使用cython从python脚本调用c代码.我已经设法使用here的示例了,但问题是：我的c代码包括来自opencv的非标准库.我相信我没有正确链接它们,因此我需要有人来查看我的setup.py以及cpp_rect.h和cpp_rect.cpp文件.

我遇到的错误与* .cpp文件中的粗体行yn有关：cv :: Mat img1(7,7,CV_32FC2,Scalar(1,3));当我尝试测试库时,在执行$python userect.py时收到包含错误：

Traceback (most recent call last):
  File "userect.py", line 2, in <module>
    from rectangle import Rectangle
ImportError: dlopen(/Users/marcelosalloum/Desktop/python_cpp_interface/rectangle.so, 2): Symbol not found: __ZN2cv3Mat10deallocateEv
  Referenced from: /Users/marcelosalloum/Desktop/python_cpp_interface/rectangle.so
  Expected in: flat namespace
 in /Users/marcelosalloum/Desktop/python_cpp_interface/rectangle.so

找不到符号(__ZN2cv3Mat10deallocateEv)与cv :: Mat :: deallocate()函数有关,这表明我的导入无法正常工作.

有任何想法吗？

我的其他课程如下：

这是我的setup.py文件.请注意,尽管不确定执行是否正确,但我已经包含了2个目录：

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(
  name = 'Demos',
  ext_modules=[
    Extension("rectangle",
              sources=["rectangle.pyx", "cpp_rect.cpp"], # Note, you can link against a c++ library instead of including the source
              include_dirs=[".", "/usr/local/include/opencv/", "/usr/local/include/"],
              language="c++"),
    ],
  cmdclass = {'build_ext': build_ext},

)

我的cpp_rect.h文件包括一个cv.h和一个命名空间cv,如下所示：

#include "source/AntiShake.h"
#include <iostream>
#include "cv.h"
using namespace cv;

class Rectangle {
public:
    int x0, y0, x1, y1;
    Rectangle();
    Rectangle(int x0, int y0, int x1, int y1);
    ~Rectangle();
    int getLength();
    int getHeight();
    int getArea();
    void move(int dx, int dy);
    **void openCV();**
    Rectangle operator+(const Rectangle& other);
};

而我的openCV()函数只是从opencv实例化一个cv :: Mat(文件cpp_rect.cpp)：

#include "cpp_rect.h"

Rectangle::Rectangle() {
    x0 = y0 = x1 = y1 = 0;
}

Rectangle::Rectangle(int a, int b, int c, int d) {
    x0 = a;
    y0 = b;
    x1 = c;
    y1 = d;  
}

Rectangle::~Rectangle() {
}

void Rectangle::openCV(){
    **cv::Mat img1(7,7,CV_32FC2,Scalar(1,3));**
}
...

我可以使用以下命令来编译该文件：$python setup.py build_ext –inplace,它为我提供了* .so文件.但是,当我运行userect.py脚本时,出现该问题首先描述的包含错误.

有任何想法吗？

解决方法:

已解决,感谢DietmarKühl的评论和this video from youtube！

什么问题？我发现我的setup.py配置错误.应该是这样的：

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(
    name = 'DyCppInterface',
    version = '1.0',
    author = 'Marcelo Salloum dos Santos',
    # The ext modules interface the cpp code with the python one:
    ext_modules=[
        Extension("rectangle",
            sources=["rectangle.pyx", "cpp_rect.cpp"], # Note, you can link against a c++ library instead of including the source
            include_dirs=[".","source" , "/opt/local/include/opencv", "/opt/local/include"],
            language="c++",
            library_dirs=['/opt/local/lib', 'source'],
            libraries=['opencv_core', 'LibCppOpenCV'])
    ],
    cmdclass = {'build_ext': build_ext},
)

为了正确配置它,需要注意三件事：

> include_dirs：setup.py或.h和.cpp中的每个引用文件都应在include_dirs中具有其容器文件夹；
> library_dirs：每个引用的库都应在此处编写其容器文件夹；
>图书馆：必须在此处输入图书馆的名称

观看this video on how to use and configure a dynamic library (using Eclipse CDT),可以回答有关如何为cython配置库的其他问题.

标签：opencv,cython,distutils,python,c-4
来源： https://codeday.me/bug/20191122/2063061.html