python/c++ 混合编程

官方简介

pybind11 is a lightweight header-only library that exposes C++ types in Python and vice versa, mainly to create Python bindings of existing C++ code. Its goals and syntax are similar to the excellent Boost.Python library by David Abrahams: to minimize boilerplate code in traditional extension modules by inferring type information using compile-time introspection.

google translate---->

pybind11是一个轻量级的“Header-only”的库，它将C++的类型暴露给Python，反之亦然。主要用于将已经存在的C++代码绑定到Python。pybind11的目标和语法都类似于boost.python库。通过使用编译时内省推断类型信息，最大限度地减少传统扩展模块中的样板代码。

C++代码api.cpp

#include <pybind11/pybind11.h> // 导入 pybind11 的 C++ 库
#include <iostream>

namespace py = pybind11;

int add(int i, int j) {
   return i + j;
}

class Pet
{
public:
    std::string name;
    int age;
    Pet() {}
    Pet(const std::string name_, const int age_){
        name = name_;
        age = age_;
    }
    ~Pet(){
        std::cout << "destructed" << std::endl;
    }
    void setName(std::string name_)
    {
        name = name_;
    }
    const std::string getName()
    {
        return name;
    }

};

PYBIND11_MODULE(api, m) {                                                                           // 创建一个 Python 模块，名为 api ，用变量 m 表示
    py::class_<Pet>(m, "Pet")                                                                       // 用 class_ 可以绑定一个 C++ 的 class 或 struct
        .def(py::init<const std::string, const int>(), py::arg("name") = "tom", py::arg("age") = 2) // 带有默认值的、关键字参数 构造函数初始化
        .def_readwrite("name", &Pet::name)                                                          // 绑定类变量
        .def_readonly("age", &Pet::age)                                                             // 绑定类变量并限制为只读（修改时会抛出 AttributeError 异常）
        .def("setName", &Pet::setName)                                                              // 绑定类方法
        .def("getName", &Pet::getName);
    m.doc() = "pybind11 example plugin";                                                            // 可选的模块说明
    m.def("add", &add, "a function which adds two numbers",                                         // 绑定函数
                py::arg("i") = 2,
                py::arg("j") = 3);
}

编译so文件

g++ api.cpp -o api.so -O3 -Wall -std=c++11 -shared -fPIC `python3 -m pybind11 --includes`

python调用

进入python终端后

Python 3.7.0 (default, Jun 28 2018, 13:15:42)
[GCC 7.2.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import api
>>> api.add(i = 4,j = 5)
9
>>> p = api.Pet(age = 2233)
>>> p.name
'tom'
>>> p.age
2233
>>>

参考链接

pybind11官方文档

demo参考