See the differences between my, local, and our (and 'use vars').
In a nutshell, 'my' is the most widely used of the four. It defines a variable scoped to the current scope (which could be an entire file). It cannot be referred to from different scopes.
'local' lets you redefine a 'global' (package) variable for the current scope. If you want to make printing a list really simple, for instance, you might use something like
print @list;
this will set $, (usually '') and $\ (usually '') to $/ (usually "\n") for the current scope.
'our' tells perl that you will be using the names package variable. For a normal program (i.e., not a package) using this, it tells perl that the 'variable' part of 'our variable' will refer to '*main::variable' (where * is the proper glyph). For instance,
our $abc = 123;
is exactly the same as
which is the same as
$abc = 123;
when there is no locally scoped $abc (e.g., with 'my' or 'local') for the current scope. 'our' and 'use vars' do essentially the same thing, but 'our' is now the recommended way to do it.
$abc = 123;
is the same as
$abc = 123;
In a nutshell, 'my' is the most widely used of the four. It defines a variable scoped to the current scope (which could be an entire file). It cannot be referred to from different scopes.
'local' lets you redefine a 'global' (package) variable for the current scope. If you want to make printing a list really simple, for instance, you might use something like
Code:
local $, = local $\ = $/; print @list;
this will set $, (usually '') and $\ (usually '') to $/ (usually "\n") for the current scope.
'our' tells perl that you will be using the names package variable. For a normal program (i.e., not a package) using this, it tells perl that the 'variable' part of 'our variable' will refer to '*main::variable' (where * is the proper glyph). For instance,
Code:
package main; our $abc = 123;
is exactly the same as
Code:
$main::abc = 123; # but you have to use $main::abc instead of $abcwhich is the same as
Code:
no strict; $abc = 123;
when there is no locally scoped $abc (e.g., with 'my' or 'local') for the current scope. 'our' and 'use vars' do essentially the same thing, but 'our' is now the recommended way to do it.
Code:
use vars qw/$abc/; $abc = 123;
is the same as
Code:
our $abc; $abc = 123;