堆(Heap)和栈(Stack)不同，堆是给进程用的，用来存储各个线程申请的内存块。
不能同时在堆上进行Alloc操作，这就意味这如果2个线程同时执行new操作，那么一个可以执行，另一个要等到这个执行完毕才可以执行new——否则的话，可能返回同一个地址，而线程还傻乎乎的以为是不同的呢。因此，如果想获取高效率而不出现问题(当然还有其他原因)，那么可以另外创建一个堆来使用。使用函数HeapCreate来创建一个堆。
从堆中分配内存：HeapAlloc
改变已分配内存大小:HeapReAlloc
获取已分配内存块大小:HeapSize
释放已分配内存块:HeapFree
销毁堆:HeapDestroy
可是，此时使用new操作符，仍将在默认的堆上分配空间，我们需要在新的堆上来分配空间，此时需要重载对应类的new和delete操作符。
class CSomeClass
{
private:
static HANDLE s_hHeap;
static UINT s_uNumAllocsInHeap;
// Other private data and member functions
public:
void* operator new (size_t size);
void operator delete (void* p);
// Other public data and member functions
};
HANDLE CSomeClass::s_hHeap
= NULL;
UINT CSomeClass::s_uNumAllocsInHeap = 0;void* CSomeClass::operator new (size_t size)
{
if(s_hHeap == NULL)
{
// Heap does not exist; create it.
s_hHeap = HeapCreate(HEAP_NO_SERIALIZE, 0, 0);if(s_hHeap == NULL)
return(NULL);
}
// The heap exists for CSomeClass objects.
void* p = HeapAlloc(s_hHeap, 0, size);if(p != NULL)
{
// Memory was allocated successfully; increment
// the count of CSomeClass objects in the heap.
s_uNumAllocsInHeap++;
}// Return the address of the allocated CSomeClass object.
return(p);
}
void CSomeClass::operator delete (void* p)
{
if(HeapFree(s_hHeap, 0, p))
{
// Object was deleted successfully.
s_uNumAllocsInHeap--;
}if(s_uNumAllocsInHeap == 0)
{
// If there are no more objects in the heap,
// destroy the heap.
if(HeapDestroy(s_hHeap))
{
//Set the heap handle to NULL so that the new operator
//will know to create a new heap if a new CSomeClass
//object is created.
s_hHeap = NULL;
}
}
}
本章末尾讲解了其他堆操作函数，但用途似乎不大，可以选看。
