Ptr& lt; Node& gt;a = CreateObject& lt;节点& gt;(); [英] Ptr<Node> a = CreateObject < Node > ();

问题描述

当我在NS-3(网络模拟器)中浏览不同的示例时，我遇到了这样的定义.我不知道这个语法到底是什么意思.

While i am going through different examples in NS-3 ( network simulator) i came across a definition like this. I coudn't figure out what exactly this syntax means.

Ptr<Node>  a = CreateObject < Node > ();  

在其他一些情况下，它们使用相似的语法，但RHS却大不相同.

In some other cases they use similar syntax, but RHS is quite different.

HelperClass帮助；

HelperClass help;

Ptr< xxx > a = help.somethingrandom();

，或者在 xxx 之前加 const 前缀.

我想这是用c ++创建对象的另一种方式.但这仍然令人困惑.任何人都可以详细说明发生了什么吗?提前致谢.

I guess this is a different way of creating objects in c++. But it is still confusing. Can anyone please elaborate whats happening ? Thanks in advance.

推荐答案

假定 Ptr 是一些智能指针类.看来 CreateObject 是模板函数，其实现可以简单地归结为:

Assuming Ptr is some smart pointer class. It seems CreateObject is template function, with implementation that simply boils down to this:

template<typename Obj>
Ptr<Obj> CreateObject() {
  return Ptr<Obj>(new Obj);
}

这个想法是代码是通用的，它将适用于任何类型.如果构造函数碰巧抛出异常，则使用函数可确保在多次初始化期间不会发生资源泄漏.

The idea is that the code is generic, it will work for any type. Using a function ensures no resources leak during multiple initializations, if a constructor happens to throw an exception.

标准库具有等效的 std :: shared_ptr / std :: unique_ptr 和匹配的 std :: make_shared / std:: make_unique 函数.

The standard library has an equivalent std::shared_ptr/std::unique_ptr with matching std::make_shared/std::make_unique functions.

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