Re: Garbage Collection - The Trash Begins To Pile Up

"Nevin :-] Liber" <>
2 Jan 2007 14:25:51 -0500
In article <>,
 Walter Bright <> wrote:

For the potential problem with the free store, just throw an exception:

    Object *o = new Object();
    foo(); // foo() throws an exception, o is now leaked
    return o;

And how does does GC magically fix this code?

There are two bugs here: the memory leak, and that Object may never be
destroyed. GC can only address the first one.

Unless the caller knows that Object only manages memory, the code is
still just as buggy. And I really don't want a tight coupling between
Object and everyone that uses it. The users of Object should not have
to know about its internals; otherwise, we have effectively eliminated
encapsulation and data hiding.

If I write the code as:

   std::auto_ptr<Object> o(new Object());
   foo(); // foo() throws an exception, o is NOT leaked
   return o;

I don't have the leak, the non-destruction bug, nor the tight coupling.

You've got such potential every time you use free store. And every time
you use RAII, you have the potential for a dangling pointer.

And every time you use GC you have the potential of a non-destruction

Don't get me wrong; I want GC. But this is a real issue with it.

 Nevin ":-)" Liber <> 773 961-1620

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