的unique_ptr提振相同呢？ [英] unique_ptr boost equivalent?

问题描述

有没有在升压库C ++ 1X的性病一些等价类::的unique_ptr？我在寻找的是能够有一个异常安全的工厂函数，行为像这样...

 的std ::的unique_ptr＆LT;基地以及GT; create_base（）
{
    返回的std ::的unique_ptr＆LT;基地以及GT（新的派生）;
}无效some_other_function（）
{
    的std ::的unique_ptr＆LT;基地以及GT; B = create_base（）;    //做一些东西用b，可能会或可能不会引发异常...    //现在b为自动的破坏。
}
 

编辑：现在，我使用这个技巧，这似乎是最好的，我可以在这一点上得到...

 基础* create_base（）
{
    返回新的派生;
}无效some_other_function（）
{
    提高:: scoped_ptr的＆LT;基地以及GT; B = create_base（）;    //做一些东西用b，可能会或可能不会引发异常...    //现在b为自动地删除。
}
 

解决方案

这是不可能没有的C ++ 0x（它是标准的一部分，以创建像的unique_ptr 库，所以升压并不需要提供它）。

没有具体右值引用，这是C ++ 0x中，一个健壮的实现中的unique_ptr A的功能是不可能的，有或无的推动作用。

在C ++ 03，有几个可能的选择，虽然各自有各自的缺陷。

• 的boost :: shared_ptr的大概是capabilites方面最简单的更换。您可以放心地使用它的任何地方你，否则会使用一个的unique_ptr 键，它会工作。它只是不会被视为有效，因为添加的引用计数。但是，如果你正在寻找一个简单的简易替换这是能够处理一切的unique_ptr 能做到的，这可能是你最好的选择。 （当然，一个的shared_ptr 可以做更多的事情为好，但它也可以简单地作为一个下拉更换为的unique_ptr ）


• 的boost :: scoped_ptr的类似于的unique_ptr ，但不允许所有权转移。只要智能指针是为了保持其整个生命周期独家拥有它的伟大工程。


• 的std :: auto_ptr的作品非常相似，的unique_ptr ，但有一些限制，主要是它不能存储在标准库的容器中。如果你只是寻找一个指针，使所有权转移，但并不意味着要存储在容器中或周围复制，这可能是一个不错的选择。

Is there some equivalent class for C++1x's std::unique_ptr in the boost libraries? The behavior I'm looking for is being able to have an exception-safe factory function, like so...

std::unique_ptr<Base> create_base()
{
    return std::unique_ptr<Base>(new Derived);
}

void some_other_function()
{
    std::unique_ptr<Base> b = create_base();

    // Do some stuff with b that may or may not throw an exception...

    // Now b is destructed automagically.
}

EDIT: Right now, I'm using this hack, which seems like the best I can get at this point...

Base* create_base()
{
    return new Derived;
}

void some_other_function()
{
    boost::scoped_ptr<Base> b = create_base();

    // Do some stuff with b that may or may not throw an exception...

    // Now b is deleted automagically.
}

解决方案

It's not possible to create something like unique_ptr without C++0x (where it's part of the standard library, and so Boost doesn't need to provide it).

Specifically without rvalue references, which are a feature in C++0x, a robust implementation of unique_ptr is impossible, with or without Boost.

In C++03, there are a few possible alternatives, although each have their flaws.

• boost::shared_ptr is probably the simplest replacement in terms of capabilites. You can safely use it anywhere you'd otherwise use a unique_ptr and it'd work. It just wouldn't be as efficient, because of the added reference counting. But if you're looking for a simple drop-in replacement that's able to handle everything unique_ptr can do, this is probably your best bet. (Of course, a shared_ptr can do a lot more as well, but it can also simply be used as a drop-in replacement for unique_ptr.)
• boost::scoped_ptr is similar to unique_ptr but does not allow transfer of ownership. It works great as long as the smart pointer is meant to retain exclusive ownership throughout its lifetime.
• std::auto_ptr works very similar to unique_ptr, but has a few limitations, mainly that it can not be stored in standard library containers. If you're simply looking for a pointer that allows transfer of ownership, but which is not meant to be stored in containers or copied around, this is probably a good bet.

这篇关于的unique_ptr提振相同呢？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！