非可复制类型的整数可索引RAII容器 [英] Integer index-able RAII container for non-copyable type

问题描述

是否有标准容器具有与向量< T> 相同的通用API，但通过直接默认构造填充新位置？

Is there a standard container that has the same general API as vector<T> but that populates new locations via direct default construction?

背景：

我有一种类型禁止复制，有一个默认的构造函数，我真正想做的是这样：

I have a type that disallows copying but has a default constructor and what I really want to do is this:

vector<NoCopy> bag(some_size);

// use bag[i]'s

return; // bag & contents get correctly cleaned up. 

但是，这不起作用，因为 vector< T& 按照默认构建对象的方式实现，然后将其复制到每个新位置。

However, this doesn't work because vector<T>(int) is implemented in terms of default constructing an object and then copying it into each of the new locations.

编辑：不是C ++ 0xB（aka C ++ 11）

Not C++0xB (a.k.a. C++11)

推荐答案

一个选择是升级到C ++ 11标准库实现。

One option would be to upgrade to a C++11-compliant Standard Library implementation.

在C ++ 11中，向量（size_type）构造函数default构造N个元素到容器中。它既不复制也不移动任何元素。

In C++11, the vector(size_type) constructor default constructs N elements into the container. It neither copies nor moves any elements.

Visual C ++ 2010不支持此C ++ 11功能;我相信Visual C ++ 11开发者预览正确支持它。我不知道最新版本的libstdc ++是否支持这个;我怀疑libc ++。

Visual C++ 2010 does not support this C++11 feature; I believe the Visual C++ 11 Developer Preview does correctly support it though. I do not know whether recent versions of libstdc++ support this; I would suspect that libc++ does.

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