了解CComBSTR赋值运算符

问题描述

说我有以下：

  BSTR myBSTR = SysAllocString（LMYBSTR）; 
 CComBSTR myCComBSTR = myBSTR; 
  

myCComBSTR $ c> myBSTR ，当它超出范围时释放它？或者它是否创建 myBSTR 的副本并产生内存泄漏，如果我不自由 myBSTR ？

如果这产生内存泄漏，什么是最有效的处理方式？ （ myBSTR 将作为 BSTR 传递给函数，我想将它存储为<$ c $ code>实例创建一个独立的副本。您需要手动释放 myBSTR 以避免泄漏。

解决这种情况最简单的方法是跳过中间人 SysAllocString 函数

  CComBSTR myCComBSTR = LMYBSTR 
  

另一方面，如果你有一个 BSTR 并且想要拥有 CComBSTR 的所有者船，然后使用附加方法。此方法将资源的所有权从源 BSTR 转移到 CComBSTR 实例。

  CComBSTR myCComBSTR; 
 myCComBSTR.Attach（myBSTR）; 
  

Say I have the following:

BSTR myBSTR = SysAllocString( L"MYBSTR" );
CComBSTR myCComBSTR = myBSTR;

Does myCComBSTR take ownership of myBSTR and free it when it goes out of scope? Or does it make a copy of myBSTR and produce a memory leak if i dont free myBSTR?

If this produces a memory leak, what's the most efficient way of handling this? (myBSTR will be passed in to a function as a BSTR and i want to store it as a CComBSTRinternally)

解决方案

In this case the CComBSTR instance creates an independent copy. You will need to manually free myBSTR to avoid a leak.

The simplest approach to fix this scenario is to skip the middle man SysAllocString function

CComBSTR myCComBSTR = L"MYBSTR";

On the other hand if you have a BSTR and want to have a CComBSTR take owner ship of it then use attach method. This method transfers ownership of the resource from the source BSTR to the CComBSTR instance.

CComBSTR myCComBSTR;
myCComBSTR.Attach(myBSTR);

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