揭露非const但在加速Python的不可复制成员 [英] Expose a non-const but noncopyable member in Boost Python

问题描述

下面是我的问题：

我有两个类这样的：

class Signal {
public:
    void connect(...) { sig.connect(...); }
private:
    boost::signal2::signal sig;
};

class MyClass {
public:
    Signal on_event;
};

我想揭露 MyClass的:: ON_EVENT ，这样我可以叫 my_class_instance.on_event.connect（...）从Python的。

I would like to expose MyClass::on_event so that I can call my_class_instance.on_event.connect(...) from Python.

这是我是如何包装这些类：

This is how I've wrapped those classes:

class_<Signal, boost::noncopyable> ("Signal", noinit)
    .def("connect", &some_helper_function);

class_<MyClass> ("MyClass")
    .def_readonly("on_event", &MyClass::on_event);

这编译，但是当我尝试调用连接在Python，我得到： AttributeError的：不能设置属性。这是在这里解释的：的http://www.boost.org/doc/libs/1_53_0/libs/python/doc/tutorial/doc/html/python/exposing.html,所以我改成 .def_readwrite 为 ON_EVENT 。

This compiles, but when I try to call connect from Python I get: AttributeError: can't set attribute. This is explained here: http://www.boost.org/doc/libs/1_53_0/libs/python/doc/tutorial/doc/html/python/exposing.html, so I changed to .def_readwrite for on_event.

但现在我得到一个编译时错误信息。它几乎是不可能的阅读C ++模板的错误消息，但据我了解它，因为的boost :: signals2 ::信号是不可复制。由于 .def_readwrite 使得成员分配它不能是不可复制。但是，对于我的使用，我不想要分配的成员，我只是wan't调用的方法。

But now I get a compile time error instead. Its an almost impossible to read C++ template error message, but as far as I understand it its because boost::signals2::signal is noncopyable. Since .def_readwrite makes the member assignable it must not be noncopyable. But for my usage I don't want to assign the member, I just wan't to call one method.

我想过使得连接 信号常量，即使它改变了对象，但后来我的方法不能叫 sig.connect（）从该方法，所以这是一个没有去以及..

I thought about making the connect method of Signal const, even though it alters the object, but then I couldn't call sig.connect() from that method, so that was a no go as well..

任何想法？

推荐答案

写了这个问题之后，我添加了一个公共的拷贝构造函数来信号，现在，它的工作原理。

After writing this question I added a public copy constructor to Signal and now it works.

这篇关于揭露非const但在加速Python的不可复制成员的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！