Garbage collected pointers?

[rikki cattermole]

On 01/03/2018 11:10 PM, John Burton wrote:
> In the language spec here :-
> https://dlang.org/spec/garbage.html#pointers_and_gc
> 
> It refers to a distinction between pointers to garbage collected memory 
> and pointers that are not. In particular it says that with a non garbage 
> collected pointer you can do anything  that is legal in C but with a 
> garbage collected pointer there are a lot of undefined behaviors if you 
> don't follow some restrictions.
> 
> My question is how do I tell if a pointer is "garbage collected" or not?
> 
> For example :-
> * Do not store magic values into pointers, other than null.
> 
> So how do I tell if it's safe to do this for any individual pointer? 
> What makes a pointer "garbage collected"?

You cannot tell if a random pointer is owned by the GC or not.

If a piece of memory is allocated not by the GC in your own function, 
that's fairly easy. You'll know about it thanks to calling e.g. malloc 
versus new or .length.