PERL Beginners - XML::Writer creates a file but fails to be recognized

Author

XML::Writer creates a file but fails to be recognized

Dave Adams

2007-04-26, 6:58 pm

When generating a file with XML::Writer the script certainly builds the file
but when I go to test for it, it fails. Does anyone have a reason why? How
do I create a file that I can use in the rest of my script?

use XML::Writer;
use IO::File;
my $output = new IO::File(">test.xml");
my $writer = new XML::Writer(OUTPUT => $output);
$writer->startTag("greeting","class" => "simple");
$writer->characters("Hello, world!");
$writer->endTag("greeting");
$writer->end();
$output->close();

#Test to make sure this file exist before preceding
if (! -r $output) {
print ("ERROR: can't read /$output XML file.");
}

Rob Dixon

2007-04-26, 6:58 pm

Dave Adams wrote:
>
> When generating a file with XML::Writer the script certainly builds the
> file but when I go to test for it, it fails. Does anyone have a reason why?
> How do I create a file that I can use in the rest of my script?
>
> use XML::Writer;
> use IO::File;
> my $output = new IO::File(">test.xml");
> my $writer = new XML::Writer(OUTPUT => $output);
> $writer->startTag("greeting","class" => "simple");
> $writer->characters("Hello, world!");
> $writer->endTag("greeting");
> $writer->end();
> $output->close();
>
> #Test to make sure this file exist before preceding
> if (! -r $output) {
> print ("ERROR: can't read /$output XML file.");
> }

Please, always

use strict;
use warnings;

at the start of your programs. That will find a lot of simple problems.

You're testing whether your file handle $output is opened to a read-permitted
file. First of all you opened it write-only so you won't be able to read from
the handle even if you have read permissions. Secondly you've closed the handle,
so it's not referring to a file at all any more.

Just open the file for read, checking any errors you get. If you don't
have read permission then the open will fail:

open my $in, 'test.xml' or die "ERROR: can't read XML file: $!";

while (<$in> ) {
print;
}

HTH,

Rob

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