operator new / operator delete等的重载

最新推荐文章于 2025-10-10 11:20:07 发布

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本文介绍了一个C++类MemoryDemo，该类重载了new和delete运算符以实现自定义内存管理。通过重载不同形式的new和对应的delete，确保了内存分配与释放的一致性。






class MemoryDemo
{
public:
	MemoryDemo() {}
	~MemoryDemo() {}
	
	void* operator new(size_t size) throw(bad_alloc);
	void operator delete(void* ptr) throw();

	void* operator new[] (size_t size) throw(bad_alloc);
	void operator delete[](void* ptr) throw();

	void* operator new(size_t size, const nothrow_t&) throw();
	void operator delete(void* ptr, const nothrow_t&) throw();

	void* operator new[](size_t size, const nothrow_t&) throw();
	void operator delete[](void* ptr, const nothrow_t&) throw();

};

void* MemoryDemo::operator new(size_t size) throw(bad_alloc)
{
	cout<< "operator new!\n";
	return (::operator new(size));
}

void MemoryDemo::operator delete(void* ptr) throw()
{
	cout<< "operator delete!\n";
	::operator delete(ptr);
}

void* MemoryDemo::operator new[](size_t size) throw(bad_alloc)
{
	cout<<"operator new[]!\n";
	return (::operator new[](size));
}

void MemoryDemo::operator delete[](void* ptr) throw()
{
	cout<<"operator delete[]!\n";
	::operator delete[](ptr);
}

void* MemoryDemo::operator new(size_t size, const nothrow_t&) throw()
{
	cout<<"operator new nothrow!\n";
	return (::operator new(size,nothrow));
}
void MemoryDemo::operator delete(void* ptr, const nothrow_t&) throw()
{
	cout<<"operator delete nothrow!\n";
	::operator delete[](ptr,nothrow);
}

void* MemoryDemo::operator new[](size_t size, const nothrow_t&) throw()
{
	cout<<"operator new[] nothrow!\n";
	return (::operator new[](size,nothrow));
}
void MemoryDemo::operator delete[](void* ptr, const nothrow_t&) throw()
{
	cout<<"operator delete[] nothrow!\n";
	::operator delete[](ptr,nothrow);
}

void main()
{
	MemoryDemo* pMem = new MemoryDemo();
	delete pMem;

	pMem = new MemoryDemo[10];
	delete []pMem;

	pMem = new (nothrow) MemoryDemo();
	delete pMem;

	pMem = new (nothrow) MemoryDemo[10];
	delete []pMem;

}

在重载 operator new时，还要重载相应形式的 operator delete，否则，会按你指定的方式分配内存，但释放时则按照内置yuyi
，可能存在不兼容。