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Posted: **Sun Sep 14, 2008 3:42 am**

I've already implemented a malloc and free functions. Since I'm creating a C++ kernel, now I need to implement new and delete too...
Initially I thinked that

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void *operator new(size_t size) {
        return malloc(size);
}

Is the only think I need. But I read that new and delete also call constructors and deconstructors. How can I call the contructor of the new class?
I also read that the return type of new isn't void * but a pointer to the type of the parameter.
Eg

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new(sizeof(short int)) returns short int *
new(Class1()) returns Class1 *

How is this done in C++?

Thanks

Posted: **Sun Sep 14, 2008 4:28 am**

Use of operator new and delete automatically calls the constructors and destructors, you don't need to do that in your implementation.

And yes, the return type automatically gets converted to a pointer to the type being allocated. Also, your usage of new in that example is wrong - new takes a type as a parameter, not a size. It should be:

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new short int;

If you want to pass arguments to constructors when allocating a class, use:

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new MyClass(foo, bar);

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new and delete implementation

new and delete implementation

Re: new and delete implementation