On implementing a linked list I hit to some unexpected (doesn't mean incorrect though) behaviour.

 ptest = ^test;
 test = record
 p:
pointer;
 end;
 new(mytest);

When I allocate "mytest" the pointer
variable "p" is initialized as $ffffffff instead of nil as I did suspect. In my code though I am relying on the fact that new pointers are indeed nil so I can allocate them accordingly. How can I force and rely on the fact that p is always nil? What is the correct procedure here?

TIA, Darius

Newly allocated memory is never zeroed out. You must do this manually with FillChar or FillWord. This is only done automatically for class instances.

I will add a note to the docs.

Michael.

Michael Van Canneyt wrote

On Fri, 16 Dec 2011,

[1] wrote

> On implementing a linked list I

hit to some unexpected (doesn't mean incorrect though) behaviour. ptest = ^test; test = record p: pointer; end; new(mytest); When I allocate "mytest" the pointer variable "p" is initialized as $ffffffff instead of nil as I did suspect. In my code though I am relying on the fact that new pointers are indeed nil so I can allocate them accordingly. How can I force and rely on the fact that p is always nil? What is the correct procedure here?

Newly allocated memory is never zeroed out. You

must do this manually with FillChar or FillWord.

This is only done

automatically for class instances.

I wasn't sure about this, but now I know.

Thanks Michael.

Links:
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[1]

Also you can Zero out records using:

var r: TSomeRec = ();

Or access the record fields and nil out the ones you want, but () gets it all done in one shot.