使用XPath Extractor时如何忽略JMeter中有关html标记的错误(How to ignore errors about html tags in JMeter when using XPath Extractor)

 
 
 不属于新对象的最后10个字节会发生什么。 
 
 
 什么都没有。 Placement-new不接触它。 它不知道该内存块中是否还存在其他东西。 您可以轻松地为2个bar对象分配大小，在后10个字节中构造一个bar对象，然后在前10个字节中构造另一个bar对象。 想想如果placement-new做了一些事情来超越你提供的内存地址的边界会发生什么，它会破坏内存后半部分的标准。 不好。 所以它不会这样做。 
 
 
 
 放置新分区只需要所需的内存量，在这种情况下是10bytes吗？ 
 
 
 是。 Placement-new只需调用bar构造函数，将指定的内存地址作为初始化构造函数的起始地址传递给它。 构造函数只会初始化它所需的内存部分。 由于bar类是10个字节，因此可以初始化不超过10个字节。 剩余的10个字节不受影响。 
 
 
 
 或者指针只是携带额外的10个字节，直到它被解除分配。 
 
 
 如果分配20个字节并在前10个字节中构造一个bar ，则剩余的10个字节将简单地存在于内存中的bar对象之后，但不是bar对象本身的一部分。 你可以用这10个字节做任何你想做的事。 
 
 
 
 另一种情况，让我说我首先开始为类吧分配内存，这是10个字节。 然后我将放置新的类foo，即20个字节。 编译器会分配更多内存吗？ 
 
 
 No. Placement-new只是在您提供的内存地址构造指定的类。 您有责任确保内存足够大以容纳正在构建的类。 
 
 
 
 或者我必须确保事先分配足够的内存？ 
 
 
 是。 

 
 
What happens to the last 10 bytes that is not part of the new object.
 
 
Nothing at all. Placement-new does not touch it. It would not know if something else already existed in that block of memory. You could easily allocate size for 2 bar objects, construct a bar object in the second 10 bytes, then construct another bar object in the first 10 bytes. Think of what would happen if placement-new did something to overstep the bounds of the memory address you provide and it corrupted the bar in the second half of the memory. Not good. So it doesn't do that.
 
 
 
Does placement new partition only the amount of memory required, which is in this case 10bytes?
 
 
Yes. Placement-new would simply call the bar constructor, passing it the specified memory address as the starting address for the constructor to initialize. The constructor would initialize only the portion of the memory it needs. Since the bar class is 10 bytes, no more than 10 bytes can be initialized. The remaining 10 bytes are untouched.
 
 
 
Or does the pointer just carry around the extra 10 bytes until it is deallocated.
 
 
If you allocate 20 bytes and construct a bar in the first 10 bytes, the remaining 10 bytes would simply exist after the bar object in memory, but not be part of the bar object itself. You can do whatever you want with those 10 bytes.
 
 
 
And another case, lets say I've first started of by allocating memory for class bar, which is 10 bytes. I'll then placement new class foo, which is 20 bytes. Will the compiler allocate more memory?
 
 
No. Placement-new simply constructs the specified class at the memory address you provide. It is your responsibility to ensure that memory is large enough to hold the class being constructed.
 
 
 
Or do I have to make sure to allocate enough memory beforehand?
 
 
Yes.