CODEWITHSUNDEEP
perl
Paul Rubel
Paul Rubel

Reputation: 27222

BAREWORD filehandles: bareword "DATA" not allowed

I'm trying to read some tgz data from the __END__ section of a perl script. I'm running into problem with the filehandle, sometimes using it doesn't cause a problem and sometimes the script throws an error.

Here's some example code, I know the data isn't tgz but it does show the problem.) 

#!/usr/bin/env perl
use strict;
use warnings;

my $raw_time = (stat(DATA))[9];
my $size     = -s DATA;
my $kilosize = int($size / 1024) . 'k';

print "<P>Script size is $kilosize at $raw_time\n";

#print ref(DATA);    #UNCOMMENT TO SEE THE PROBLEM?

__DATA__
DO NOT REMOVE THE PRECEDING LINE.
Everything else in this file will be ignored.

If I run this script I get

$ /tmp/data.pl 
<P>Script size is 0k at 1500655490

DATA seems OK to use.

But, if I uncomment print ref(DATA); I get an error on that line:

Bareword "DATA" not allowed while "strict subs" in use at /tmp/data.pl line 12.
Execution of /tmp/data.pl aborted due to compilation errors.

Why isn't the use of DATA earlier also a problem?

[pre-post update] If I change the line to be 

print "ref:". ref(\*DATA);

It doesn't throw the compile error. What's going on?

Upvotes: 0

Views: 798

Answers (1)

Sinan &#220;n&#252;r
Sinan &#220;n&#252;r

Reputation: 118138

Others have explained what's going on. In contexts where perl expects a filehandle/fileglob, it is OK to use DATA. But, in a context, such as ref(DATA) where there is no a priori reason to assume that the argument is a file handle/glob, that does not work.

is there a lexical filehandle solution for DATA?

I am not quite sure what you are after, but this might help:

#!/usr/bin/env perl

use strict;
use warnings;

# You could use any variable name you like
my $DATA_FH;

CHECK { $DATA_FH = \*DATA }

print <$DATA_FH>

__DATA__
One

Upvotes: 4

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