On 8/4/22 02:50, demerphq wrote:
On Thu, 4 Aug 2022 at 01:58, Mark Murawski
<markm-li...@intellasoft.net> wrote:
I'm still not getting something... if I want to fix the code-as-is
and do this:
FNsv = get_sv("main::_FN", GV_ADD);
if (!FNsv)
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
errmsg("couldn't fetch $_FN")));
save_item(FNsv); /* local $_FN */
I dont get the sequence here. You take the old value of $main::_FN and
then you localize it after you fetch it? That seems weird.
hv = newHV(); // create new hash
hv_store_string(hv, "name", cstr2sv(desc->proname));
Really you shouldnt do this until you have safely managed the
refcounts of all your newly created objects so that if this die's
nothing leaks.
I take this to mean , setting up FNsv first, and then allocating hv?
But in this case we seem to have a chicken/egg problem? How can you set
up FNsv to point to hv without first setting up hv?
WARNING: Attempt to free unreferenced scalar: SV 0x55d5b1cf6480,
Perl interpreter: 0x55d5b17226c0
Why are you decrementing hv? You dont own hv anymore, it's owned by
svFN and after the sv_setsv() call also FNsv. You shouldnt mess with
its refcount anymore.
The ownership aspect is making more sense now, thanks for clarifying.
Obviously in perl we can write:
my %hash;
$main::_FN= \%hash;
And in XS we can do the same thing. Unfortunately there isn't a
utility sub to do this currently, it has been on my TODO list to add
one for some time but lack of round tuits and all that.
You want code something like this:
sv_clear(FNsv); /* undef the sv */
sv_upgrade(FNsv,SVt_RV);
SvRV_set(FNsv, (SV*)hv);
SvROK_on(FNsv);
Again, make liberal use of sv_dump() it is the XS version of
Data::Dumper more or less.
I have been playing with sv_dump()... At the end of this flow, the
refcount to FNsv is 1 and should get automatically cleaned up by Perl,
right? I still have a leak here, using the above code.
Also... i get a crash when I use sv_clear(FNsv); right away like this.
If I take it out, the code seems to all run correctly, but I have a leak
and the hash or the hash reference is not being cleaned up.
Thanks.
