Commit | Line | Data |
---|---|---|
657b208b | 1 | package bytes; |
5bc28da9 | 2 | |
b75c8c73 MS |
3 | our $VERSION = '1.00'; |
4 | ||
d5448623 GS |
5 | $bytes::hint_bits = 0x00000008; |
6 | ||
5bc28da9 | 7 | sub import { |
d5448623 | 8 | $^H |= $bytes::hint_bits; |
5bc28da9 NIS |
9 | } |
10 | ||
11 | sub unimport { | |
d5448623 | 12 | $^H &= ~$bytes::hint_bits; |
5bc28da9 NIS |
13 | } |
14 | ||
15 | sub AUTOLOAD { | |
657b208b | 16 | require "bytes_heavy.pl"; |
5bc28da9 NIS |
17 | goto &$AUTOLOAD; |
18 | } | |
19 | ||
20 | sub length ($); | |
21 | ||
22 | 1; | |
23 | __END__ | |
24 | ||
25 | =head1 NAME | |
26 | ||
657b208b | 27 | bytes - Perl pragma to force byte semantics rather than character semantics |
5bc28da9 NIS |
28 | |
29 | =head1 SYNOPSIS | |
30 | ||
657b208b GS |
31 | use bytes; |
32 | no bytes; | |
5bc28da9 NIS |
33 | |
34 | =head1 DESCRIPTION | |
35 | ||
393fec97 | 36 | WARNING: The implementation of Unicode support in Perl is incomplete. |
21bad921 | 37 | See L<perlunicode> for the exact details. |
393fec97 | 38 | |
657b208b GS |
39 | The C<use bytes> pragma disables character semantics for the rest of the |
40 | lexical scope in which it appears. C<no bytes> can be used to reverse | |
41 | the effect of C<use bytes> within the current lexical scope. | |
393fec97 | 42 | |
5de28535 SC |
43 | Perl normally assumes character semantics in the presence of character |
44 | data (i.e. data that has come from a source that has been marked as | |
45 | being of a particular character encoding). When C<use bytes> is in | |
46 | effect, the encoding is temporarily ignored, and each string is treated | |
47 | as a series of bytes. | |
48 | ||
49 | As an example, when Perl sees C<$x = chr(400)>, it encodes the character | |
50 | in UTF8 and stores it in $x. Then it is marked as character data, so, | |
51 | for instance, C<length $x> returns C<1>. However, in the scope of the | |
52 | C<bytes> pragma, $x is treated as a series of bytes - the bytes that make | |
53 | up the UTF8 encoding - and C<length $x> returns C<2>: | |
54 | ||
55 | $x = chr(400); | |
56 | print "Length is ", length $x, "\n"; # "Length is 1" | |
57 | printf "Contents are %vd\n", $x; # "Contents are 400" | |
58 | { | |
59 | use bytes; | |
60 | print "Length is ", length $x, "\n"; # "Length is 2" | |
61 | printf "Contents are %vd\n", $x; # "Contents are 198.144" | |
62 | } | |
63 | ||
64 | For more on the implications and differences between character | |
393fec97 GS |
65 | semantics and byte semantics, see L<perlunicode>. |
66 | ||
67 | =head1 SEE ALSO | |
68 | ||
69 | L<perlunicode>, L<utf8> | |
5bc28da9 NIS |
70 | |
71 | =cut |