There is a $NO_UNDEF_PARAMS var in new versions of CGI.pm (in 2.78, not in 2.74) but the default is 0 so this is not the problem. I presume you understand the difference between exists and defined with respect to hashes. Your results are not repeatable vis:

use strict;
use CGI;
use Data::Dumper;
my %fields;

my $q = new CGI ( 'name=&value=&void=' );
print "got param '$_'\n" for $q->param;
$fields{$_} = $q->param($_) for $q->param;
print Dumper($q, \%fields);


__END__
got param 'name'
got param 'value'
got param 'void'
$VAR1 = bless( {
                 'void' => [
                             ''
                           ],
                 '.charset' => 'ISO-8859-1',
                 '.parameters' => [
                                    'name',
                                    'value',
                                    'void'
                                  ],
                 '.fieldnames' => {},
                 'value' => [
                              ''
                            ],
                 'name' => [
                             ''
                           ]
               }, 'CGI' );
$VAR2 = {
          'void' => '',
          'value' => '',
          'name' => ''
        };
[download]

The .fieldnames should actually contain the fieldnames (this is really a bug) but the ultimate behaviour is not broken. I presume you have an old version of CGI.pm which does not have the .parameters part in the object and works off .fieldnames which was the behaviour pre 2.63? I think. Which version do you have?

cheers

tachyon

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