Here is foobarbaz.pl, which sets some default values: 
#!/usr/local/bin/perl -w
#
use strict;
use diagnostics;

use vars qw( $qux $quo $zip );

$foo = 1;
$bar = 2;
$baz = 3;
$qux = 4;
$quo = 5;
$zip = 6;

sub hello {
  print "Hello, World!\n"
}

[download]
And here is program.pl: 
#!/usr/local/bin/perl -w
#
use strict;
use diagnostics;

use vars qw( $foo $bar $baz );

require 'foobarbaz.pl';

# OK, but need package name for $qux, $quo, $zip
print "$_\n" foreach( $foo, $bar, $baz, $::qux, $::quo, $::zip );

hello(); # fine

#print $qux;     ## XXX gives an error

while (my ($k,$v) = each %:: ) {
  print $k . ":\t\t" . $v . "\n";
}

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In program.pl, when printing the symbol table, the identifiers for $qux, $quo, $zip appear in main's symbol table, but I can only access them by explicitly providing the package name. This throws a warning, however: Name "main::zip" used only once: possible typo at require.pl line 11 (same warning for $qux and $quo).

Normally, when using a separate file to initialize variables, I would declare all the variables in program.pl with use vars (or make the separate file a module that uses Exporter). I was just curious to see the effects of use vars in a require()d file. I do not understand why the identifiers exist in main's symbol table, but appear 'hidden' to an extent. Can anyone enlighten me?

Thanks much!
--sacked

In reply to use vars in a require()d file by sacked

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