in reply to Re^3: Parallel Modules ?
in thread Parallel Modules ?

Thanks for the comments.

use threads;
Somehow, I am not able to pass parameters to sub routines using threads->create.
Below are the sample code and errors.

Better.pm 

package Better;

sub saveBetter {
   my ($sbn, $cost, $ur) = @_;

   print "sbn:  $sbn\n";
   print "cost: $cost\n";
   print "url:  $url\n";
   return;
}

1;

[download]

test.pl
#!/usr/bin/perl -w

use strict;
use warnings;
use threads;
use Better;

my $sbn = "123489876";
my $lee = "12.89";
my $abc = "abcde";

my @ParamList = ($sbn, $lee, $abc);

my $thr = threads->create(Better::saveBetter, @ParamList);

$thr->join();

[download]
./test.pl
Use of uninitialized value in concatenation (.) or string at Better.pm line 6.
sbn: Use of uninitialized value in concatenation (.) or string at Better.pm line 7.
cost: Use of uninitialized value in concatenation (.) or string at Better.pm line 8.
url: Thread 1 terminated abnormally: Undefined subroutine &main::123489876 called at ./test.pl line 14.

Changed code to 
#!/usr/bin/perl -w

use strict;
use warnings;
use threads;
use Better;

my $sbn = "123489876";
my $lee = "12.89";
my $abc = "abcde";

my $thr = threads->create(Better::saveBetter, $sbn, $lee, $abc);

$thr->join();

[download]

Still got same error.

Any idea?
Some output of perl -V

perl -V
Summary of my perl5 (revision 5 version 8 subversion 8) configuration: Platform:
osname=linux, osvers=2.6.18-128.1.10.el5, archname=x86_64-linux-thread-multi uname='linux ls20-bc2-13.build.redhat.com 2.6.18-128.1.10.el5 #1 smp wed apr 29 13:53:08 edt 2009 x86_64 x86_64 x86_64 gnulinux '
usethreads=define use5005threads=undef useithreads=define usemultiplicity=define

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Re^5: Parallel Modules ?
by BrowserUk (Patriarch) on Nov 29, 2011 at 23:09 UTC

    Your problem is this line:

    my $thr = threads->create(Better::saveBetter, @ParamList);
##.......................^^^^^^^^^^^^^^^^^^

    [download]

    The indicated part (Better::saveBetter) is invoking that subroutine and then passing the result to threads->create() as the first argument.

    Replace that line with:

    my $thr = threads->create( \&Better::saveBetter, @ParamList );

    [download]

    And your sample will work.

    Or rather it will once you correct the typo:

       my ($sbn, $cost, $ur) = @_;
#..................^^^

   print "url:  $url\n";
#..............^^^^

    [download]

    Which would have been caught if you had use strict & use warnings in your module.

    And would be far more obvious visually if you formatted your code with spaces in the right places:

       my( $sbn, $cost, $ur ) = @_;

    [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.

    The start of some sanity?
[reply]
[d/l]
[select]

      Thanks a lot for your help. However, I got "Segmentation fault" with my real code. Then, I used "perl -d" and "s" command to step through all the sub routines. Looks like the failure is related to LibXML. Any idea how to make it work?

      ......

      DB<1> s
      XML::LibXML::Node::CLONE_SKIP(/usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/XML/LibXML.pm:1249): 1249: return $XML::LibXML::__threads_shared ? 0 : 1;

      DB<1> s
      XML::LibXML::XPathContext::CLONE_SKIP(/usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/XML/LibXML/XPathContext.pm:25): 25: sub CLONE_SKIP { 1 }

      DB<1> s
      XML::LibXML::CLONE_SKIP(/usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/XML/LibXML.pm:414): 414: return $XML::LibXML::__threads_shared ? 0 : 1;

      DB<1> s
      XML::LibXML::SAX::CLONE_SKIP(/usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/XML/LibXML/SAX.pm:26): 26: return $XML::LibXML::__threads_shared ? 0 : 1;

      DB<1> s
      Segmentation fault

      I use the modules below.

      use strict;
use warnings;
use Scalar::Util 'reftype';
use encoding "utf8";
use Data::Dumper;
use CGI qw(:standard Vars);
use LWP::UserAgent;
use XML::Simple;
use threads;

      [download]

[reply]
[d/l]

        I'm guessing that you are trying to use a single instance of some object across multiple threads.

        It'd be a hell of a lot easier to help you if you posted the actual code.

        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.

        The start of some sanity?
[reply]

In Section Seekers of Perl Wisdom