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

EHLO all,
could you please help to make a shared hashref inside Perl C module?
Further, the value returned by a function should be a multilevel hashref/arrayref.

Part of C code: 
SV*
myfunc()
    PREINIT:
        HV *hash;
    CODE:
        hash = newHV();
        RETVAL = newRV_noinc((SV*)hash);
    OUTPUT:
        RETVAL

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Perl code: 
#!/usr/bin/perl -w

use strict;
use warnings;
use threads;
use threads::shared;
use Data::Dumper;
use lib qw|. t ../blib/arch ../blib/lib|;
use mymodule;
use Devel::Peek;
use Clone;

my $d : shared;

$d = mymodule::myfunc();

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The output: 
Invalid value for shared scalar at ./a.pl line 15.

[download]

PS: All functions already done. I need to make the return values "shared for threads". Thanks.

Replies are listed 'Best First'.
Re: How to make thread-save data on C API
by BrowserUk (Patriarch) on Sep 20, 2013 at 12:14 UTC

    See SvSHARE(), SvLOCK & SvUNLOCK in perlapi.

    Alternatively, you might do:

    use threads;
use threads::shared; 

my $d : shared;

$d = shared_clone( mymodule::myfunc() );

    [download]
    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
      Thanks for the info. Unfortunately, the SvSHARE does not work for me - I always receive empty HASHREF: 
      rt = newHV();
SvSHARE((SV*)rt);
sv = newSViv(42);
//SvSHARE(sv);
hv_stores(rt, "fe", sv);
...
ST(i) = sv_2mortal((SV*)newRV_noinc((SV*)rt));
XSRETURN(4);
---
result for this tuple:
$VAR1 = {};

      [download]
      So, I have shared HASH, but without any contents inside hash... I'll use shared_clone, but I think I can reproduce/clone the shared_clone source code...
[reply]
[d/l]
        So, I have shared HASH, but without any contents inside hash

        No. I can't make it work either :(

        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

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