3 $strict::VERSION = "1.08";
5 # Verify that we're called correctly so that strictures will work.
6 unless ( __FILE__ =~ /(^|[\/\\])\Q${\__PACKAGE__}\E\.pmc?$/ ) {
7 # Can't use Carp, since Carp uses us!
8 my (undef, $f, $l) = caller;
9 die("Incorrect use of pragma '${\__PACKAGE__}' at $f line $l.\n");
17 my %explicit_bitmask = (
27 if (exists $bitmask{$s}) {
28 $^H |= $explicit_bitmask{$s};
30 else { push @wrong, $s };
31 $bits |= $bitmask{$s} || 0;
35 Carp::croak("Unknown 'strict' tag(s) '@wrong'");
40 my @default_bits = qw(refs subs vars);
44 $^H |= bits(@_ ? @_ : @default_bits);
49 $^H &= ~ bits(@_ ? @_ : @default_bits);
57 strict - Perl pragma to restrict unsafe constructs
72 If no import list is supplied, all possible restrictions are assumed.
73 (This is the safest mode to operate in, but is sometimes too strict for
74 casual programming.) Currently, there are three possible things to be
75 strict about: "subs", "vars", and "refs".
81 This generates a runtime error if you
82 use symbolic references (see L<perlref>).
88 print $$ref; # runtime error; normally ok
90 print $file "Hi!"; # error; note: no comma after $file
92 There is one exception to this rule:
97 is allowed so that C<goto &$AUTOLOAD> would not break under stricture.
102 This generates a compile-time error if you access a variable that was
103 neither explicitly declared (using any of C<my>, C<our>, C<state>, or C<use
104 vars>) nor fully qualified. (Because this is to avoid variable suicide
105 problems and subtle dynamic scoping issues, a merely C<local> variable isn't
106 good enough.) See L<perlfunc/my>, L<perlfunc/our>, L<perlfunc/state>,
107 L<perlfunc/local>, and L<vars>.
110 $X::foo = 1; # ok, fully qualified
111 my $foo = 10; # ok, my() var
112 local $baz = 9; # blows up, $baz not declared before
115 our $bar; # Declares $bar in current package
116 $bar = 'HgS'; # ok, global declared via pragma
118 The local() generated a compile-time error because you just touched a global
119 name without fully qualifying it.
121 Because of their special use by sort(), the variables $a and $b are
122 exempted from this check.
126 This disables the poetry optimization, generating a compile-time error if
127 you try to use a bareword identifier that's not a subroutine, unless it
128 is a simple identifier (no colons) and that it appears in curly braces or
129 on the left hand side of the C<< => >> symbol.
132 $SIG{PIPE} = Plumber; # blows up
133 $SIG{PIPE} = "Plumber"; # fine: quoted string is always ok
134 $SIG{PIPE} = \&Plumber; # preferred form
138 See L<perlmodlib/Pragmatic Modules>.
142 C<strict 'subs'>, with Perl 5.6.1, erroneously permitted to use an unquoted
143 compound identifier (e.g. C<Foo::Bar>) as a hash key (before C<< => >> or
144 inside curlies), but without forcing it always to a literal string.
146 Starting with Perl 5.8.1 strict is strict about its restrictions:
147 if unknown restrictions are used, the strict pragma will abort with
149 Unknown 'strict' tag(s) '...'
151 As of version 1.04 (Perl 5.10), strict verifies that it is used as
152 "strict" to avoid the dreaded Strict trap on case insensitive file