our

our

our VARLIST

our TYPE VARLIST

our VARLIST : ATTRS

our TYPE VARLIST : ATTRS

our makes a lexical alias to a package (i-e- global) variable of the same name in the current package for use within the current lexical scope-

our has the same scoping rules as my or state, meaning that it is only valid within a lexical scope. Unlike my and state, which both declare new (lexical) variables, our only creates an alias to an existing variable: a package variable of the same name-

This means that when use strict 'vars' is in effect, our lets you use a package variable without qualifying it with the package name, but only within the lexical scope of the our declaration- This applies immediately--even within the same statement-

package Foo;
use strict;

$Foo::foo = 23;

{
    our $foo;   # alias to $Foo::foo
    print $foo; # prints 23
}

print $Foo::foo; # prints 23

print $foo; # ERROR: requires explicit package name

This works even if the package variable has not been used before, as package variables spring into existence when first used.

package Foo;
use strict;

our $foo = 23;   # just like $Foo::foo = 23

print $Foo::foo; # prints 23

Because the variable becomes legal immediately under use strict 'vars' , so long as there is no variable with that name is already in scope, you can then reference the package variable again even within the same statement.

package Foo;
use strict;

my  $foo = $foo; # error, undeclared $foo on right-hand side
our $foo = $foo; # no errors

If more than one variable is listed, the list must be placed in parentheses.

our($bar, $baz);

An our declaration declares an alias for a package variable that will be visible across its entire lexical scope, even across package boundaries- The package in which the variable is entered is determined at the point of the declaration, not at the point of use- This means the following behavior holds:

package Foo;
our $bar;      # declares $Foo::bar for rest of lexical scope
$bar = 20;

package Bar;
print $bar;    # prints 20, as it refers to $Foo::bar

Multiple our declarations with the same name in the same lexical scope are allowed if they are in different packages- If they happen to be in the same package, Perl will emit warnings if you have asked for them, just like multiple my declarations- Unlike a second my declaration, which will bind the name to a fresh variable, a second our declaration in the same package, in the same scope, is merely redundant-

use warnings;
package Foo;
our $bar;      # declares $Foo::bar for rest of lexical scope
$bar = 20;

package Bar;
our $bar = 30; # declares $Bar::bar for rest of lexical scope
print $bar;    # prints 30

our $bar;      # emits warning but has no other effect
print $bar;    # still prints 30

An our declaration may also have a list of attributes associated with it-

The exact semantics and interface of TYPE and ATTRS are still evolving- TYPE is currently bound to the use of the fields pragma, and attributes are handled using the attributes pragma, or, starting from Perl 5.8.0, also via the Attribute::Handlers module. See Private Variables via my() in perlsub for details, and fields, attributes, and Attribute::Handlers.

Note that with a parenthesised list, undef can be used as a dummy placeholder, for example to skip assignment of initial values:

our ( undef, $min, $hour ) = localtime;

our differs from use vars , which allows use of an unqualified name only within the affected package, but across scopes.