Conspiracy Theory #1

[Denis Koroskin]

On Fri, 20 Nov 2009 17:28:07 +0300, dsimcha <dsimcha at yahoo.com> wrote:

> == Quote from Travis Boucher (boucher.travis at gmail.com)'s article
>> dsimcha wrote:
>> > == Quote from Travis Boucher (boucher.travis at gmail.com)'s article
>> >> Sean Kelly wrote:
>> >>  Its harder
>> >> to create a memory leak in D then it is to prevent one in C.
>> >
>> > void doStuff() {
>> >     uint[] foo = new uint[100_000_000];
>> > }
>> >
>> > void main() {
>> >     while(true) {
>> >         doStuff();
>> >     }
>> > }
>> >
>> Hmm, that seems like that should be an implementation bug.  Shouldn't
>> foo be marked for GC once it scope?  (I have never used new on a
>> primitive type, so I don't know)
>
> It's conservative GC.  D's GC, along with the Hans Boehm GC and probably  
> most GCs
> for close to the metal languages, can't perfectly identify what's a  
> pointer and
> what's not.  Therefore, for sufficiently large allocations there's a high
> probability that some bit pattern that looks like a pointer but isn't  
> one will
> keep the allocation alive long after there are no "real" references to  
> it left.

Aren't uint array allocations have hasPointers flag set off? I always  
thought they aren't scanned for pointers (unlike, say, void[]).