eval_pv leaking

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

Hi Perl Friends, Here's a try at embedding perl, taken mostly from perlembed. The problem is that each call to eval_pv() leaks about 387 bytes. Am I doing something wrong?

#include <EXTERN.h>
#include <perl.h>

int
main(int argc, char **argv)
{   
    char *embedding[] = { "", "-e", "1" };
    PerlInterpreter *interp = perl_alloc();
    perl_construct(interp);

    if (perl_parse(interp, NULL, 3, embedding, (char **)NULL) != 0)
    {
        warn("perl_parse");
        return -1;
    }   
    
    if (perl_run(interp) != 0)
    {   
        warn("perl_run");
        return -1;
    }
    
    // leak repeatedly
    for (;;)
        eval_pv("1", TRUE);
    
    perl_destruct(interp);
    perl_free(interp);
    return 0;
}
[download]

Comment on eval_pv leaking Download Code

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Re: eval_pv leaking by Joost (Canon) on Dec 27, 2004 at 17:09 UTC
From the perlapi manpage (emphasis mine): eval_pv Tells Perl to "eval" the given string *and return an SV result*. I tried using `SV ret = eval_pv("1;", TRUE); SvREFCNT_dec(ret);` [download] but that didn't work (probably because eval_pv works "kindof like a subroutine" in that it returns a mortal SV* - or something; I confess ignorance of the subtleties in perlembedding) - so messed around with the code until I came up with this: `for (;;) { ENTER; SAVETMPS; SV* ret = eval_pv("1;", TRUE); FREETMPS; LEAVE; }` [download] Which doesn't leak for me (perl, v5.8.5 built for i686-linux-thread-multi). update: this is not really documented AFAIK, probably because you're not likely to be calling eval_* all that much. The perlembed documentation should probably mention something about how to deal with the return value (as it does describe handling the various call_* parameters and return values). "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l] [select]
Re^2: eval_pv leaking by PreferredUserName (Pilgrim) on Dec 27, 2004 at 19:40 UTC
This works for me as well. Thanks!	[reply]
Version info by PreferredUserName (Pilgrim) on Dec 27, 2004 at 16:35 UTC
Forgot to include version stuff. Here it is: Read more... (3 kB)	[reply] [d/l]
Re: eval_pv leaking by demerphq (Chancellor) on Dec 27, 2004 at 16:40 UTC
IMO you should redirect this question to P5P. --- demerphq	[reply]