Question

我有一张地图，其中键值是2维指针的地址，值是关于图像的一些元数据。

当我在分配和释放函数上运行valgrind时，valgrind显示无效的4错误读取。

struct MemType
{
    // Store the data type of the pointer
    int dataType;
    int noOfRows;
    int noOfColumns;
    int noOfItems;
};

map < unsigned long, MemType > _MemHandle2DPointer;


short** AllocateMemory(int rowSize, int columnSize)
{

    short** ptr2D = new short*[rowSize];
    for (unsigned int i = 0; i < rowSize; i++)
    {
        ptr2D[i] = new short[columnSize];

        //Initialize the memory
        for(unsigned int j = 0; j < columnSize; j++)
        {
            ptr2D[i][j] = 0;
        }
    }

    // Assign type id and add to the list of 2D pointers
    MemType mem2DType;

    mem2DType.dataType = 0;
    // Store the number of rows and columns
    mem2DType.noOfRows = rowSize;
    mem2DType.noOfColumns = columnSize;
    mem2DType.noOfItems = 0;

    // Insert the pointer into the map
    _MemHandle2DPointer[(long) ptr2D] = mem2DType;

    return ptr2D;
}

void ReleaseMemory (short** ptr2D)
{


    // Releasing memory occupied by 2D pointer
    if (ptr2D != NULL)
    {
        map < unsigned long, MemType >::iterator iter = _MemHandle2DPointer.find((long)ptr2D);
        if (iter != _MemHandle2DPointer.end())
        {
            //cout<<" Releasing Memory occupied by 2D pointer \n";
            _MemHandle2DPointer.erase((long)ptr2D);


            for (unsigned int i = 0; i < iter->second.noOfRows; i++)
            {
                delete [] (short *) ptr2D[i];               
            }

            delete [] (short **) ptr2D;
            ptr2D = NULL;
        }       

    }

}


int main()
{

 short** dminImage = AllocateMemory(100,200);

 ReleaseMemory (dminImage);

return 0;
}

我通过此解决方法解决了这个问题。

void ReleaseMemory（短** ptr2D） {

// Releasing memory occupied by 2D pointer
if (ptr2D != NULL)
{
    map < unsigned long, MemType >::iterator iter = _MemHandle2DPointer.find((long)ptr2D);
    if (iter != _MemHandle2DPointer.end())
    {
        //cout<<" Releasing Memory occupied by 2D pointer \n";
    //  _MemHandle2DPointer.erase((long)ptr2D);


        for (unsigned int i = 0; i < iter->second.noOfRows; i++)
        {
            delete [] (short *) ptr2D[i];

        }
        _MemHandle2DPointer.erase((long)ptr2D);
        delete [] (short **) ptr2D;
        ptr2D = NULL;
    }       

}

}

我对导致早期错误的原因感到困惑。没有规定使用智能指针或任何c ++ 11 stuff.it是遗留代码。

Answer 1

您正在删除具有迭代器的map元素，然后仍然使用迭代器。不要那样做。迭代器通过擦除它指向的元素而失效。

清除图像地图

1 个答案: