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Perl Documentation

NAME

strict - Perl pragma to restrict unsafe constructs

SYNOPSIS

use strict;
use strict "vars";
use strict "refs";
use strict "subs";
use strict;
no strict "vars";

DESCRIPTION

The strict pragma disables certain Perl expressions that could behave unexpectedly or are difficult to debug, turning them into errors. The effect of this pragma is limited to the current file or scope block.

If no import list is supplied, all possible restrictions are assumed. (This is the safest mode to operate in, but is sometimes too strict for casual programming.) Currently, there are three possible things to be strict about: "subs", "vars", and "refs".

See "Pragmatic Modules" in perlmodlib.

HISTORY

strict 'subs', with Perl 5.6.1, erroneously permitted to use an unquoted compound identifier (e.g. Foo::Bar) as a hash key (before => or inside curlies), but without forcing it always to a literal string.

Starting with Perl 5.8.1 strict is strict about its restrictions: if unknown restrictions are used, the strict pragma will abort with

Unknown 'strict' tag(s) '...'

As of version 1.04 (Perl 5.10), strict verifies that it is used as "strict" to avoid the dreaded Strict trap on case insensitive file systems.