Re: clear a array to avoid memory leak

Walt Chen wrote:
> Hi
> 
> I am new to XS but have coded for perl and C for a few year. Maybe
> this question sounds stupid but I can not figure it out on perlgut and
> perlxs at the moment.

Fairly new to XS myself...

> I have an array which contains several reference of new created
> hashes. I know that if I use method newRV_noinc for av_push in
> construction stage, the reference to each hash is 1.
> 
> After the code does some stuff, I need to clear the array as I want to
> refill it. I have made my code in a concise example as following. Now
> I wonder whether av_clear will decrement the reference number of hash1
> and hash2 to 0. If it does, then hash would be destroyed
> automatically, else I have to destroy it explicitly to avoid memory
> leak. Could anyone point it out for me?

Can't find a definitive statement in the usual docs either. But an
on-line copy of Advanced Perl Programming google found for me says:
"[av_clear] Decrements the reference counts of its constituent scalars
and replaces those positions with undef. It leaves the array intact."

So it seems it will indeed delete/free the hashes.

Cheers,
Mark.

> 
> ==========================================================================================
> int size1 = 20;
> int size2 = 21;
> char name1[] = "foo1";
> char name2[] = "foo2";
> 
> HV *hash1 = newHV();
> hv_store(hash1, "name",  strlen("name"),  newSVpv(name1,0),  0);
> hv_store(hash1, "size",  strlen("size"),  newSViv(size1),  0);
> av_push(array, newRV_noinc((SV*)hash1));  //reference to hash1 is 1
> 
> HV *hash2 = newHV();
> hv_store(hash2, "name",  strlen("name"),  newSVpv(name2,0),  0);
> hv_store(hash2, "size",  strlen("size"),  newSViv(size2),  0);
> av_push(array, newRV_noinc((SV*)hash2));  //reference to hash2 is 1
> 
> .......
> av_clear(array); //whether reference number of hash1 and hash2
> decremented here??