Default Integer Pointer Values

[Maurizio Cimadamore]

On 03/10/2019 05:12, Ty Young wrote:
> Hi,
>
>
> Recently I've stumbled upon a potential issue in regards to an 
> allocated integer pointer:
>
>
> Pointer<Integer> valuePointer = <Lib>.scope().allocate(NativeTypes.INT);
>
>
> This basic integer pointer works fine of course. However, for some 
> reason the pointer has a value already set despite never been given 
> one. In potential functions that don't have proper return code 
> values(enums, technically), these values could be potentially seen as 
> valid values when in reality they are not. In some cases I think these 
> values can even change from run-to-run, making the issue even worse.
>
>
> Would the expected behavior here not be to have the wrapped value be 
> NULL or is there reasons as to why it does this?

Currently, when we allocate memory we do not zero it - which is why you 
are seeing what you are seeing, I believe.

I agree that we will need to go there - but we're looking at ways to do 
the zero-init that are more efficient as the current techniques 
(Unsafe.memorySet) are excessively punitive on large allocations. There 
was some discussion on this some time ago:

https://mail.openjdk.java.net/pipermail/panama-dev/2019-January/003773.html

I'm trying (among the other things) to pick this up again, and see if 
some better solution can be achieved here.

Maurizio