placement new

by

代码直接在gcc里是可以编译通过的，在vc里编译，注意，如果是将例子代码加到MFC程序里，要注释掉源码中的DEBUG_NEW：

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/*
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
*/

代码如下：

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class Zone {
public:
	Zone()
	{}
	~Zone()
	{}
 
	void* New(size_t size)
	{
		// add your own allocating strategy here.
		return NULL;
	}
};
 
class ZoneObject {
public:
	void* operator new(size_t size, Zone* zone){ return zone->New(size); }
 
		void operator delete(void*, size_t) {}
	void operator delete(void* pointer, Zone* zone) {}
};
 
class Example0 : public ZoneObject {
public:
	Example0(int a0, const char *b0)
	{
	}
	~Example0()
	{
	}
};
 
class Example1 {
public:
	Example1(int a0, const char *b0)
	{
	}
	~Example1()
	{
	}
};
 
int main()
{
	Zone zone0;
	Zone *zone = &zone0;
	Example0 *example0 = new (zone)Example0(0, "hi");
	example0->~Example0();
	free(example0);
 
	Example1 *example1 = (Example1 *)malloc(sizeof(Example1));
	example1 = new (example1)Example1(0, "hi1");
	example1->~Example1();
	free(example1);
	return 1;
}