perl XS - suspected memory leak (works)

kopolov has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I need help with suspected memory leak in this XS code:

u32
findEAsForGivenRAAndContext(u64 raAddress, u64 lpid, u64 pid, AV* eaAr
+ray)
    PREINIT:
        u32 resultCount=0;
        int i=0;
        int maxCount=10*MAX_NUM_OF_ALIASES;
        unsigned long long int array[maxCount];
    CODE:
        RETVAL = findEAsForGivenRAAndContext(raAddress, lpid, pid, arr
+ay);
        resultCount = RETVAL;
           for(i=0; i<resultCount; i++) {
            SV * sv = newSVnv(array[i]);
            av_push(eaArray, sv);
        }
    OUTPUT:
        RETVAL
[download]

(I'm not sure this is the root cause of my problem, but I have a strong feeling about it)

update - no memory leaks, problem was found elsewhere

Comment on perl XS - suspected memory leak (works) Download Code

Replies are listed 'Best First'.
Re: perl XS - suspected memory leak by syphilis (Archbishop) on Apr 04, 2016 at 15:22 UTC
If you do something like: `for(1.. $large_integer) { findEAsForGivenRAAndContext($arg1, $arg2, $arg3, \@eaArray); }` [download] then @eaArray is going to get bigger and bigger, consuming more and more memory. I suppose this could perhaps be misinterpreted as a memory leak ... but it's not. I can't see anything else. (But I don't really understand this form of XS code.) Cheers, Rob	[reply] [d/l]
Re: perl XS - suspected memory leak by ikegami (Patriarch) on Apr 04, 2016 at 21:29 UTC
`av_push` calls `av_store`, which takes ownership of a refcount, so no, no memory leak. You can confirm this using `use Devel::Peek; Dump($eaArray[0]);`. It should have a REFCNT of 1.	[reply] [d/l] [select]
Re: perl XS - suspected memory leak by Anonymous Monk on Apr 04, 2016 at 16:02 UTC
`newSVnv` takes an `NV` (double), not an `unsigned long long int`. Maybe that's the cause of your feelings? Anyway, read the documentation of Devel::Peek and use it, the REFCNT should help you in debugging memory leaks.	[reply] [d/l] [select]
Re^2: perl XS - suspected memory leak by Anonymous Monk on Apr 04, 2016 at 17:26 UTC
newSVnv takes an NV (double), not an unsigned long long int. Oops, disregard that. I checked and it's a function, not a macro.	[reply]