my is probably what you want, since it creates a lexical variable that can't be tampered with outside of the block its delcared in. Take a look at this code:
#!/usr/bin/perl -wT
use strict;
# use an our-variable....
sub count_our {
our $num ||= 0;
$num++;
}
sub print_our {
our $num ||= 0;
print $num, "\n";
}
# use a my-variable....
{
my $num = 0;
sub count_my {
$num++;
}
sub print_my {
print $num, "\n";
}
}
# thousand lines of code here
# $num is common enough that we use it somewhere else as well
my $num = 10;
our $num = 10;
# thousand lines of code here
# did we mess up the 'my' variable?
count_my();
print "My count: ";
print_my();
# how about the 'our' variable?
count_our();
print "Our count: ";
print_our();
Notice that the our-variable gets fubared somewhere in the middle of this script. The my-variable is truly encapsulated and can't be modified except by count_my() and print_my().
-Blake
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