通过SWIG实现在Python中调用C++代码

2. 定义SWIG界面文件

// This line declares the module name as example. The module name 
// is what you'll use to import the generated module in the target 
// language (e.g., import example in Python).
%module example // interface to the example c++ library
// The %{ %} block is used to include the header files and any 
// other necessary C/C++ code that should be directly copied into 
// the generated wrapper code.
    // includes the SWIG interface file for the std::vector class template.
    #include "example.h" 
%include "std_vector.i";
using namespace std;
// creates a new template instantiation for std::vector<double>, naming
// it DoubleVector. This means that std::vector<double> will be wrapped 
// and available as DoubleVector in the target language.
%template(DoubleVector) vector<double>;
// This line includes the example.h header file again but this time in 
// the context of the SWIG processing. This inclusion tells SWIG to parse 
// and wrap the declarations in example.h according to the specified SWIG directives.
%include example.h
将文件存为example.i。
3. 生成Python wrapper
如果没有安装SWIG，应首先在当前Python环境下安装SWIG:
pip install swig
然后执行如下命令行：
swig -c++ -python .\example.i
执行完毕后应该生成了example.py和example_wrap.cxx两个文件。
4. 编写setup.py文件
#!/usr/bin/env python
from distutils.core import setup, Extension
# from setuptools import setup, Extension   # for python >3.12
example_module = Extension(
    '_example',
    sources = ['example_wrap.cxx', 'example.cpp']
setup (
    name = 'example',
    version = '0.1',
    author      = "Bin Yang",
    description = """Simple swig example from docs""",
    ext_modules = [example_module],
    py_modules = ["example"],
5. 编译生成可供调用的包
5.1 Ubuntu系统
执行如下命令：
python setup.py build_ext --inplace
测试时所使用的版本为Python 3.8。执行过后在当前文件夹下可以直接调用example包：
import example
example.square([1,2])
应该得到如下输出：
[1, 4]
5.2 Windows
在Windows系统下需要先安装微软的c++开发工具，总共约7GB大小！
然后执行与5.1节一样的命令。使用方法也相同。测试使用的为Python 3.9。
教程链接：
SWIG C++ python demo - YouTube
                    bilibili~Tieba(=・ω・=)
                
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