perlXS - missing object methods

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

Hi, Still on the perlXS issue (damn, its complicated) This is my header file:

#include <TM_TranslationAPI.h>
#include "TM_DefaultParams.h"

// This data structure holds an array of address and the number of act
+ual addresses
typedef struct TM_TranslationAdresses{
  u64 addressCount;
  u64 addresses[10*MAX_NUM_OF_ALIASES];
} TM_TranslationAdresses;

TM_TranslationAdresses *
findEAsForGivenRAAndContext(
  u64 raAddress,
  u64 lpid,
  u64 pid);
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As you can see - contains only one structure and one function

This is my XS file (trans.xs):


#include "/usr/include/stdio.h"
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include "ppport.h"

#include "TM_TranslationsDB.h"

MODULE = trans        PACKAGE = trans        

PROTOTYPES: ENABLE

TM_TranslationAdresses *
findEAsForGivenRAAndContext(raAddress, lpid, pid) 
  u64 raAddress
  u64 lpid
  u64 pid
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this is the typemap I use:

TYPEMAP
TM_TranslationAdresses *   T_PTROBJ
u64                   T_U_LONG_LONG
##################################################
INPUT
T_U_LONG_LONG
    $var = (unsigned long long int)SvUV($arg)
##################################################
OUTPUT
T_U_LONG_LONG
    sv_setuv($arg, (UV)$var);
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this is the trans.pm file I use:

package trans;

use 5.010001;
use strict;
use warnings;

require Exporter;

our @ISA = qw(Exporter);
our %EXPORT_TAGS = ( 'all' => [ qw(
) ] );
our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
our @EXPORT = qw(
);
our $VERSION = '0.01';

require XSLoader;
XSLoader::load('trans', $VERSION);

1;
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and finally - this is the simple perl program I try to test everything:

#!/usr/bin/perl -w
use lib '/gpfs/haifa-p4/08/tm/team/hagaih/perlWithC/trans/blib/arch/au
+to/trans';
use lib '/gpfs/haifa-p4/08/tm/team/hagaih/perlWithC/trans/blib/lib';
use trans;
use Math::BigInt;
use Data::Dumper;

my $lpid=0;
my $pid=5;
my $raAddress=Math::BigInt->new("0x00000000_01F560C0");
my $result=trans::findEAsForGivenRAAndContext($raAddress, $lpid, $pid)
+;
print $result->addressCount;
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everything compiles great. I know the C code is working since I wrote a simple C program to verify it.

but when I run the perl program I get this error:

Can't locate object method "addressCount" via package "TM_TranslationA
+dressesPtr" at test_translations.pl ...
[download]

Please ... will appreciate any help on the matter

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Re: perlXS - missing object methods by Corion (Patriarch) on Mar 28, 2016 at 08:01 UTC
I don't know much about XS, but certainly it does not create accessor methods for you. It might be that you can access the `addressCount` property through `$result->{addressCount}` but as you get back a C struct, I doubt even that is the case. I think you will need to write XS functions that return you the `addressCount` and the addresses from the C struct to Perl.	[reply] [d/l] [select]
Re^2: perlXS - missing object methods by Anonymous Monk on Mar 28, 2016 at 08:09 UTC
Sounds about right, examples in http://perldoc.perl.org/perlxs.html#Perl-Objects-And-C-Structures	[reply]
Re: perlXS - missing object methods by syphilis (Archbishop) on Mar 28, 2016 at 11:03 UTC
There's a few things to puzzle over here: Similar to your earlier attempt, I don't see anything that offers instruction on what findEAsForGivenRAAndContext() actually does. I can see the data types of its arguments, and the data type that it returns, but that's about it. Perhaps this somehow accounts for the error message about a (non-existent) "TM_TranslationAdressesPtr" package - but I really don't know how that hitherto unmentioned package earns a mention. The u64 typemapping you've done implies that your perl's IV/UV is the same size as as a signed/unsigned long long int - so I wonder why such typemapping is necessary. Is it just so that you can have the "u64" symbol as an alias for unsigned long long int ? AFAICT, when $raAddress gets passed to findEAsForGivenRAAndContext(), instead of having assigned it as: `my $raAddress=Math::BigInt->new("0x00000000_01F560C0"); it might just as well have been assigned as: my $raAddress=0x01F560C0;` [download] I would probably rewrite findEAsForGivenRAAndContext() so that it returns the 2 u64 values - such that instead of coding (in perl): `my $result=trans::findEAsForGivenRAAndContext($raAddress, $lpid, $pid) +;` [download] one codes it as: `my @result=trans::findEAsForGivenRAAndContext($raAddress, $lpid, $pid) +; print $result[0]; # addressCount` [download] But there are other ways, and perhaps I'm not looking at it right. Cheers, Rob	[reply] [d/l] [select]
Re: perlXS - missing object methods by Anonymous Monk on Mar 28, 2016 at 07:58 UTC
addressCount doesn't appear in your xs file	[reply]