c++ initializer_list 和 shared_ptr 行为

c++ initializer_list and shared_ptr behavior(c++ initializer_list 和 shared_ptr 行为)

问题描述

我正在测试 vs2013 c++ initializer_list.

I'm testing vs2013 c++ initializer_list.

可以编译下面的代码.但是当我运行 exe 时崩溃了.

The code below can be compiled. But crashes when i run exe.

#include <memory>
#include <iostream>

class Base {};

class Derived : public Base {};

void DoSomething(std::initializer_list<std::shared_ptr<Base> > list)
{
}

int main()
{
  auto ip = std::make_shared<Derived>();

  std::cout << "use_count=" << ip.use_count() << std::endl;

  DoSomething({ip, std::make_shared<Derived>()}); // ng
  // DoSomething({ip, std::make_shared<Base>()}); // ok
  // DoSomething({std::make_shared<Derived>(), ip}); // ok

  std::cout << "use_count=" << ip.use_count() << std::endl;
}

编译.

C:...>cl.exe /EHsc test.cpp
Microsoft(R) C/C++ Optimizing Compiler Version 18.00.21005.1 for x86
Copyright (C) Microsoft Corporation.  All rights reserved.

test.cpp
Microsoft (R) Incremental Linker Version 12.00.21005.1
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:test.exe
test.obj

C:...>

我期待这样的输出.g++4.8.2 是这样工作的.

I expected the output like this. g++4.8.2 works like this.

c:...>test.exe
use_count=1
use_count=1

但是，看起来像这样.

c:...>test.exe
use_count=1
use_count=0 // or some random value like 3719232 and displayed crash dialog. 

而且，修改上面的一行代码，效果很好.

And, Modifying one line of the code above, This works good.

DoSomething({std::make_shared<Derived>(), ip});

这是 vs2013 initializer_list 的错误还是正常行为?

Is this a bug or normal behavior of vs2013 initializer_list ?

推荐答案

这是 vs2013 initializer_list 的错误还是正常行为?

Is this a bug or normal behavior of vs2013 initializer_list?

是的.VS2013 的 std::initializer_list 实现有问题；看到类似的问题为什么第一个元素被销毁?和initializer_list 与 2013 年的双重删除.

Yes to both. VS2013's std::initializer_list implementation is buggy; see similar questions Why first element is destroyed? and Double delete in initializer_list vs 2013.

有人在 2013 年 11 月向 Microsoft 报告了其中一个问题:http://connect.microsoft.com/VisualStudio/feedback/details/807419/initializer-lists-leaking-memory

Someone reported one of those issues to Microsoft in November 2013: http://connect.microsoft.com/VisualStudio/feedback/details/807419/initializer-lists-leaking-memory

此问题现已在 Spring 更新中修复:修复了错误在 Visual Studio 2013 更新 2

This is now fixed in the Spring Update: Bugs Fixed in Visual Studio 2013 Update 2

这篇关于c++ initializer_list 和 shared_ptr 行为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编程学习网！