Hello mirod.

I read your post and tried. And found it seems not working good. This prints 

3
4
1
And the script is like this. Just added example xml with your script. 
#!/usr/bin/perl
use strict; use warnings; use XML::Twig;

my $xml=join('',<DATA>);
my $t=XML::Twig->new(
    start_tag_handlers => {
        _all_ => \&store_line_number,
    },
    twig_handlers => {
        _all_  => \&warn_on_empty_elt,
    },
);
$t->parse($xml);

sub store_line_number {
    my( $twig, $elt)= @_;
    $elt->set_att( '#line' => $twig->current_line);
    $elt->parent->set_att( '#not_empty') if $elt->parent;
}
sub warn_on_empty_elt {
    my( $twig, $elt)= @_;
    if( ! $elt->att( '#not_empty') && $elt->text !~ m{\S}) {
        print $elt->att( '#line'), "\n";
    }
    $twig->purge;
}
__DATA__
<gibsonca>
<abc>fds </abc> <!-- ok -->
<ddd></ddd> <!-- not ok -->
<eee> </eee> <!-- not ok -->
</gibsonca>

[download]
As you see the DATA, empty tag will be ddd, and eee(line 3,4). And print out of "1" means "gibsonca" tag. I wonder this has relation with parsing of twig, as document says,

Remember that element handlers are called when the element is CLOSED, so if you have handlers for nested elements the inner handlers will be called first.

So, as a result of purging inner elements, gibsonca tag is empty for twig, I guess.

If I comment out purge, it prints line number 3 and 4.

regards.

update: Large XML files may have some cluster that may be easy to purge. For example item tag in the below case. Maybe this will print line number of end tag(not as correct as yours), but I would like to purge like this. 
#!/usr/bin/perl
use strict; use warnings; use XML::Twig;

my $xml=join('',<DATA>);
my $t=XML::Twig->new(
    twig_handlers => {
        '/gibsonca/item//*' => \&warn_on_empty_elt, #all descendants o
+f item
        'item' => sub { $_[0]->purge; }, #purge if it is item tag
    },
);
$t->parse($xml);

sub warn_on_empty_elt {
    my( $twig, $elt)= @_;
    if ($elt->children_trimmed_text eq ''){
        printf "empty tag gi=%s,line col=%s,%s\n",
            $elt->gi, $twig->current_line,$twig->current_column;
    }
}

__DATA__
<gibsonca>
<item>
<abc>fds <test>   </test></abc> <!-- test not ok -->
<ddd></ddd> <!-- not ok -->
<eee> </eee> <!-- not ok -->
</item>
<item>
</item>
</gibsonca>

[download]

In reply to Re^2: XML Newbie by remiah
in thread XML Newbie by gibsonca

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