pybind11学习

@2023.9.1
参考pybind11官方文档：https://pybind11.readthedocs.io/en/stable/index.html
参考：https://blog.csdn.net/fengbingchun/article/details/123022405

Installing the library

我是在wsl-ubuntu中进行测试；在python虚拟环境中安装：pip install pybind11

First steps

通过一个例子，说明基本的语法，文件example.cpp

#include <pybind11/pybind11.h>
namespace py = pybind11;int add(int i = 1, int j = 2)
{return i + j;
}PYBIND11_MODULE(example, m)
{m.doc() = "pybind11 example plugin";m.def("add", &add, "A function that adds two numbers", py::arg("i") = 1, py::arg("j") = 2);// using namespace pybind11::literals;// m.def("add", &add, "A function that adds two numbers", "i"_a=1, "j"_a=2);m.attr("the_answer") = 42;py::object world = py::cast("World");m.attr("what") = world;// m.attr("what") = "world"
}

编译命令：c++ -O3 -Wall -shared -std=c++11 -fPIC $(python3 -m pybind11 --includes) example.cpp -o example$(python3-config --extension-suffix)

$ python
Python 3.9.10 (main, Jan 15 2022, 11:48:04)
[Clang 13.0.0 (clang-1300.0.29.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import example
>>> example.add(1, 2)
3
>>>> help(example)....FUNCTIONSadd(...)Signature : (i: int = 1, j: int = 2) -> intA function which adds two numbers
>>> example.the_answer
42
>>> example.what
'World'

Object-oriented code

In C++, a type is only considered polymorphic if it has at least one virtual function and pybind11 will automatically recognize this

注意：这会影响继承类的调用，参考https://pybind11.readthedocs.io/en/stable/classes.html#inheritance-and-automatic-downcasting

#include <pybind11/pybind11.h>namespace py = pybind11;struct Pet
{Pet(const std::string &name, int age) : name(name), age(age) {}void setName(const std::string &name_) { name = name_; }const std::string &getName() const { return name; }void set(int age_) { age = age_; }void set(const std::string &name_) { name = name_; }std::string name;int age;
};struct Dog : Pet
{Dog(const std::string &name, int age) : Pet(name, age) {}std::string bark() const { return "woof!"; }
};PYBIND11_MODULE(example, m) {py::class_<Pet>(m, "Pet", py::dynamic_attr()) // py::dynamic_attr()支持动态添加属性，不推荐.def(py::init<const std::string &, int>()).def("set", static_cast<void (Pet::*)(int)>(&Pet::set), "Set the pet's age").def("set", static_cast<void (Pet::*)(const std::string &)>(&Pet::set), "Set the pet's name").def("setName", &Pet::setName).def("getName", &Pet::getName).def_readwrite("name", &Pet::name).def("__repr__",[](const Pet &a){return "<example.Pet named '" + a.name + "'>";});// Method 1: template parameter:py::class_<Dog, Pet /* <- specify C++ parent type */>(m, "Dog")// Method 2: pass parent class_ object:// py::class_<Dog>(m, "Dog", pet /* <- specify Python parent type */).def(py::init<const std::string &, int>()).def("bark", &Dog::bark);
}