CODEWITHSUNDEEP
perl
KK99
KK99

Reputation: 1989

How do I use `our` variables in Perl

I have following PL and PM files

Start.PL, ConfigReader.PM, BL.PM, Logger.PM

Code extract from ConfigReader.PM 

Package ConfigReader
use Config::Simple;
use Logger;

our $configIni;
sub OpenConfigIni()
{   
    my ($cfg_ini_path)=@_;
    &Logger::LogMsg("**** OpenConfigIni starts ****","info");    
    &Logger::LogMsg($cfg_ini_path,"info");
    $configIni = new Config::Simple($cfg_ini_path);
    &Logger::LogMsg("**** OpenConfigIni ends ****","info");
}

Where Logger.PM is a custom module I have written using Log4Perl.

Code extract from BL.PM

Package BL
use strict;
use Logger;
use ConfigReader;

my %chash = %{$ConfigReader::configIni->param( -block => "UserDetails")};

Code extract from Start.PL

Start.PL is the entry point to my application which initiates Logger, ConfigReader

use strict;
use ConfigReader;
use Logger;
use BL;

&Logger::InitiateLogger();
&ConfigReader::OpenConfigIni("My_Config.ini");
my %qhash = %{$ConfigReader::configIni->param( -block => "ABC")};

Problem is

When i run Start.PL, the code fails with following error

Can't call method "param" on an undefined value at BL.pm line 9
Compilation failed in require at Start.pl line 19.
BEGIN failed--compilation aborted at Start.pl line 19.

(Ignore Line numbers)

It is pointing to following in BL.pm

my %chash = %{$ConfigReader::configIni->param( -block => "UserDetails")};

If i comment use Bl in start.Pl, the script works fine that means

my %qhash = %{$ConfigReader::configIni->param( -block => "ABC")}; works fine in Start.PL

what i am trying to achieve here is that 

1. Use the ConfigReader.PM for handling the configuration related 
2. Make use of the our $configIni in all modules
3. Initialing the Logger and ConfigReader form start.pl whioch is the entry point here

What could be the problem here?

Upvotes: 2

Views: 294

Answers (1)

Peder Klingenberg
Peder Klingenberg

Reputation: 41085

The initialization of %chash happens when BL.pm is loaded. Which happens as part of the use BL; in Start.PL. As you can see, execution of Start.PL at that point has not yet reached the call to OpenConfigIni, so the $ConfigReader::configIni variable has not yet been initialized.

The %qhash initialization in Start.pl happens after the config initialization call, so that works.

As you have discovered, initializing %chash from a function works. Initializing your various modules explicitly through initialization functions is IMO better style than relying on load order to get the initializations right. And mixing and matching doesn't work that well, as you've seen.

Upvotes: 2

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