Perl
  Home arrow Perl arrow Page 4 - Introduction to mod_perl (part 4): Per...
Dev Shed Forums 
Administration  
Apache  
BrainDump  
DHTML  
Flash  
Java  
JavaScript  
Multimedia  
MySQL  
Oracle  
Perl  
PHP  
Practices  
Python  
Reviews  
Security  
Style-Sheets  
Web Services  
XML  
Zend  
Zope  
Forums Sitemap 
IBM® developerWorks 
Dedicated Servers 
E-Commerce Hosting 
Linux Web Hosting 
Managed Hosting 
Small Business Hosting 
Download TestComplete 
VPS Hosting 
Weekly Newsletter

 
Developer Updates  
Free Website Content 
IBM Developerworks
 RSS  Articles
 RSS  Forums
 RSS  All Feeds
Write For Us Get Paid 
Request Media Kit
Contact Us 
Site Map 
Privacy Policy 
Support 
 USERNAME
 
 PASSWORD
 
 
  >>> SIGN UP!  
  Lost Password? 
PERL

Introduction to mod_perl (part 4): Perl Basics
By: Stas Bekman
  • Search For More Articles!
  • Disclaimer
  • Author Terms
  • Rating: 4 stars4 stars4 stars4 stars4 stars / 6
    2003-01-03

    Table of Contents:
  • Introduction to mod_perl (part 4): Perl Basics
  • Using Global Variables and Sharing Them Between Modules/Packages
  • Making Variables Global With strict Pragma On
  • Using Exporter.pm to Share Global Variables
  • Using the Perl Aliasing Feature to Share Global Variables
  • Using Non-Hardcoded Configuration Module Names
  • The Scope of the Special Perl Variables
  • Compiled Regular Expressions
  • References

  • Rate this Article: Poor Best 
      ADD THIS ARTICLE TO:
      Del.ici.ous Digg
      Blink Simpy
      Google Spurl
      Y! MyWeb Furl
    Email Me Similar Content When Posted
    Add Developer Shed Article Feed To Your Site
    Email Article To Friend
    Print Version Of Article
    PDF Version Of Article
     
     
     
    ADVERTISEMENT

    PCmover - $15 Off with Coupon Code CJPH7Q

    Introduction to mod_perl (part 4): Perl Basics - Using Exporter.pm to Share Global Variables
    (Page 4 of 9 )

    Assume that you want to share the CGI.pm object (I will use $q)between your modules. For example, you create it in script.pl, butyou want it to be visible in My::HTML. First, you make $qglobal.

    script.pl:
    ----------------
    use vars qw($q);
    use CGI;
    use lib qw(.); 
    use My::HTML qw($q); # My/HTML.pm is in the same dir as script.pl
    $q = CGI->new;
    
    My::HTML::printmyheader();

    Note that I have imported $q from My::HTML. And My::HTML doesthe export of $q:

    My/HTML.pm
    ----------------
    package My::HTML;
    use strict;
    
    BEGIN {
    use Exporter ();
    @My::HTML::ISA         = qw(Exporter);
    @My::HTML::EXPORT      = qw();
    @My::HTML::EXPORT_OK   = qw($q);
    }
    use vars qw($q);
    sub printmyheader{
    # Whatever you want to do with $q... e.g.
    print $q->header();
    }
    1;

    So the $q is shared between the My::HTML package andscript.pl. It will work vice versa as well, if you create theobject in My::HTML but use it in script.pl. You have truesharing, since if you change $q in script.pl, it will be changedin My::HTML as well.

    What if you need to share $q between more than two packages? Forexample you want My::Doc to share $q as well.

    You leave My::HTML untouched, and modify script.pl to include:

    use My::Doc qw($q);

    Then you add the same Exporter code that I used in My::HTML,into My::Doc, so that it also exports $q.

    One possible pitfall is when you want to use My::Doc in bothMy::HTML and script.pl. Only if you add

    use My::Doc qw($q);

    into My::HTML will $q be shared. Otherwise My::Doc will notshare $q any more. To make things clear here is the code:

    script.pl:
    ----------------
    use vars qw($q);
    use CGI;
    use lib qw(.); 
    use My::HTML qw($q); # My/HTML.pm is in the same dir as script.pl
    use My::Doc  qw($q); # Ditto
    $q = new CGI;
    
    My::HTML::printmyheader();
    My/HTML.pm
    ----------------
    package My::HTML;
    use strict;
    
    BEGIN {
    use Exporter ();
    @My::HTML::ISA         = qw(Exporter);
    @My::HTML::EXPORT      = qw();
    @My::HTML::EXPORT_OK   = qw($q);
    }
    use vars     qw($q);
    use My::Doc  qw($q);
    sub printmyheader{
    # Whatever you want to do with $q... e.g.
    print $q->header();
    My::Doc::printtitle('Guide');
    }
    1;
    My/Doc.pm
    ----------------
    package My::Doc;
    use strict;
    
    BEGIN {
    use Exporter ();
    @My::Doc::ISA         = qw(Exporter);
    @My::Doc::EXPORT      = qw();
    @My::Doc::EXPORT_OK   = qw($q);
    }
    use vars qw($q);
    sub printtitle{
    my $title = shift || 'None';
    print $q->h1($title);
    }
    1;

    More Perl Articles
    More By Stas Bekman


     

       

    PERL ARTICLES

    - Perl: A Continuing Look at Hashes and Multid...
    - Perl: Another Round with Hashes
    - Perl Hashes
    - Perl Lists: A Final Look at List::Util
    - Perl Lists: Utilizing List::Util
    - Perl Lists: The Split() Function
    - SQL and CGI with Perl and DBI
    - Perl Lists: More Functions and Operators
    - SELECT Queries and Perl
    - Perl Lists: More on Manipulation
    - Creating a Database with Perl and DBI
    - Perl: Sailing the List(less) Seas
    - Perl and DBI
    - Perl: Concatenating Text and More
    - Perl Text: Quoting Without Quote Marks

     
    Accelerating Trading Partner Performance
     
    Competing on Analytics
     
    Cost Effective Scaling with Virtualization and Coyote Point Systems
     
    Five Checkpoints to Implementing IP Telephony
     
    Hosted Email Security: Staying Ahead of New Threats
     




    © 2003-2008 by Developer Shed. All rights reserved. DS Cluster 5 hosted by Hostway