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Postings from August 2022
On 8/12/22 18:26, Mark Murawski wrote:
> On 8/12/22 18:11, Mark Murawski wrote:
>> On 8/4/22 15:10, demerphq wrote:
>>> On Thu, 4 Aug 2022 at 17:04, Mark Murawski
>>> <markm-lists@intellasoft.net> wrote:
>>>
>>> On 8/4/22 02:50, demerphq wrote:
>>>> On Thu, 4 Aug 2022 at 01:58, Mark Murawski
>>>> <markm-lists@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.
>>>
>>>
>>> You did not respond to this comment ^^
>>
>>
>> The reason for the save_item*( was because I was modeling this code
>> on another section that uses save_item() to accomplish something
>> similar (to send internal postgres details to some perl). I don't
>> know why the original author uses save_item() for this purpose.
>>
>
> Oh... I know why save_item is used. It's because this code can be
> executed multiple times in the same perl process. So each one needs
> it's own _FN
>
>
After a serious amount of trial and error... I got it to stop crashing
and I fixed the leak
HV *hv; // hash
SV *FNsv; // scalar reference to the hash
SV *SVhv;
ENTER;
SAVETMPS;
FNsv = get_sv("main::_FN", GV_ADD);
save_item(FNsv); /* local $_FN */
hv = newHV(); // create new hash
SVhv = newRV_noinc((SV *) hv);
sv_setsv(FNsv, SVhv);
hv_store_string(hv, "name", cstr2sv(desc->proname));
PUTBACK;
FREETMPS;
LEAVE;
SvREFCNT_dec_current(SVhv);
The fix I found was to put SvREFCNT_dec_current *after*
PUTBACK/FREETMPS/LEAVE
if you do the SvREFCNT_dec_current prior.. then it leaks
If the trailing end of the code looks like this... you get a leak
SvREFCNT_dec_current(SVhv);
PUTBACK;
FREETMPS;
LEAVE;
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