Here's the difference:

use strict;
use warnings;
use 5.010;

our $foo = 'hello';

sub f {
   print("$foo\n");
}

for my $foo (qw( a b c )) {
   f();  
}

--output:--
hello
hello
hello

[download]

In ikegami's example, the my is omitted in the for loop, which causes the for loop to change the global variable $foo--and the subroutine prints the global $foo (i.e. the subroutine is a closure).

In reply to Re^2: why need my in a foreach loop? by 7stud
in thread why need my in a foreach loop? by szabgab

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