对新的[]使用QSharedPointer产生“Mismatched free（）/ delete / delete []”在valgrind [英] Using QSharedPointer with new[] yields "Mismatched free() / delete / delete[]" in valgrind

问题描述

我有以下代码：

  QPair< QSharedPointer< unsigned int> someclass :: somefunction（）{
 int siz = data_size（）; 
 QSharedPointer< unsigned int> buffer（new unsigned int [siz]）; 
 
 //填充缓冲区... 
 
 return qMakePair（buffer，siz）; 
} 
  

有时， QSharedPointer 返回的这个函数将超出范围，并且在构造函数中设置的指针将被free'd。使用valgrind 3.6.1，我得到一个Mismatched free（）/ delete / delete []错误。我使用 QSharedPointer 有什么问题吗？或者我只需要使用这个valgrind警告？

解决方案

解决这个问题的方法之一是编写一个自定义的删除器，并将其传递给 QSharedPointer 的构造函数：

 模板< typename T_> 
 void do_delete（T_ buf []）
 {
 delete [] buf; 
} 
  

然后

  QSharedPointer< unsigned int> buffer（new unsigned int [siz]，do_delete< unsigned int>）; 
  

我不知道是否有更优雅的解决方案

I have the following code:

QPair<QSharedPointer<unsigned int>, int> someclass::somefunction() {
    int siz = data_size();
    QSharedPointer<unsigned int> buffer(new unsigned int[siz]);

    // Fill the buffer...

    return qMakePair(buffer, siz);
}

At some point, the QSharedPointer returned by this function will go out of scope and the pointer set in the constructor will be free'd. Using valgrind 3.6.1, I get a "Mismatched free() / delete / delete[]" error. Is there anything wrong with my use of QSharedPointer or do I just have to live with this valgrind warning?

解决方案

One way to fix this is to write a custom deleter and pass that to the constructor of QSharedPointer like so:

template <typename T_>
void do_delete(T_ buf[])
{
    delete[] buf;
}

And then

QSharedPointer<unsigned int> buffer(new unsigned int[siz], do_delete<unsigned int>);

I am not sure whether there is a more elegant solution (which would be nice)

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