in reply to Importing symbols into main when library is already in %INC

%INC prevents only the re-requiring of the module M. Although your description is unclear, after three re-readings it appears you have use M in both main and P. If that's true, then M.pm will get read once, but import will be called twice, and properly import the symbols into both P and main.

To go further, I'd need to see code, or a clearer explanation.

-- Randal L. Schwartz, Perl hacker

  • Comment on Re: Importing symbols into main when library is already in %INC

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Re: Re: Importing symbols into main when library is already in %INC
by smashdot (Initiate) on May 16, 2001 at 22:03 UTC
    Ok, I paired it down a little and noticed something different this time. NETWORK::SNMP is a module I use to define OIDs and community strings. NETWORK::Discovery is a package that uses NETWORK::SNMP. I wrote and executed the two different scripts below. Why is it that if I say "use NETWORK::Discovery;" before I say "use NETWORK::SNMP", the variable $commstring is not defined in package main? 
    nmss_/var/scripts # cat test.pl
#!/usr/bin/perl -w

use NETWORK::SNMP;
use NETWORK::Discovery;

print "$commstring\n";

nmss_/var/scripts # ./test.pl
not_real_community_string

nmss_/var/scripts # cat test2.pl
#!/usr/bin/perl -w

use NETWORK::Discovery;
use NETWORK::SNMP;

print "$commstring\n";

nmss_/var/scripts # ./test2.pl
Name "main::commstring" used only once: possible typo at ./test2.pl li
+ne 6.
Use of uninitialized value in concatenation (.) at ./test2.pl line 6.

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        I am using the standard importer, I think (I never overloaded any import function). At the beginning of NETWORK::SNMP, I have the following code (periods represent omitted code): 
        require Exporter;

@EXPORT=qw(@chassistypes $commstring $sysname $syscontact $syslocation
+ $ipadentaddr
        $cdpdevicecacheport $ipadentnetmask $cdpcacheplatform $cdpcach
+edeviceport
        $chassisid $chassistype $sysdesc $romid);
........

$commstring=`/usr/bin/cat /var/scripts/.data/commstring`;
chomp $commstring;

........

1;

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        The following code appears in NETWORK::Discovery: 
        package NETWORK::Discovery;

use NETWORK::SNMP;
use Net::SNMP;
use Net::Ping;


sub new {
...
}

sub discover_pvp {
...
}

sub getnext_device {
....
}

sub getnext_nonsnmp {
...
}

1;

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