c++ - boost python wrap c++​​类私有(private)成员

Question

我们可以用 boost python 包装 c++ 私有(private)构造函数吗？我有一个单例 C++ 类，想将它包装到 python。

我们可以用 boost python 包装 c++ 私有(private)成员函数吗？

非常感谢

Answer 1

使用这样的东西:

#include <boost/python.hpp>
#include <iostream>

using namespace boost::python;
using std::cout;

class Singleton
{
    private:
        Singleton()
        {
            cout << "Creating instance\n";
        }
    friend Singleton* create(); 
};

Singleton* pInstance_;
Singleton* create()
{       
    if(!pInstance_)
    {
        pInstance_ = new Singleton();
    }
    else
    {
        cout << "Using old instance\n";         
    }       
    return pInstance_;
}

BOOST_PYTHON_MODULE(cppmodule)
{
    def("create", create, return_value_policy<reference_existing_object>());
    class_<Singleton>("Singleton", no_init);
}

/* using singleton later in code */

Singleton* otherInstance_ = create();

session :

>>> import cppmodule
Creating instance
>>> s = cppmodule.Singleton()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: This class cannot be instantiated from Python
>>> s = cppmodule.create()
Using old instance