3 $utf8::hint_bits = 0x00800000;
8 $^H |= $utf8::hint_bits;
9 $enc{caller()} = $_[1] if $_[1];
13 $^H &= ~$utf8::hint_bits;
17 require "utf8_heavy.pl";
18 goto &$AUTOLOAD if defined &$AUTOLOAD;
19 Carp::croak("Undefined subroutine $AUTOLOAD called");
27 utf8 - Perl pragma to enable/disable UTF-8 (or UTF-EBCDIC) in source code
36 The C<use utf8> pragma tells the Perl parser to allow UTF-8 in the
37 program text in the current lexical scope (allow UTF-EBCDIC on EBCDIC based
38 platforms). The C<no utf8> pragma tells Perl to switch back to treating
39 the source text as literal bytes in the current lexical scope.
41 This pragma is primarily a compatibility device. Perl versions
42 earlier than 5.6 allowed arbitrary bytes in source code, whereas
43 in future we would like to standardize on the UTF-8 encoding for
44 source text. Until UTF-8 becomes the default format for source
45 text, this pragma should be used to recognize UTF-8 in the source.
46 When UTF-8 becomes the standard source format, this pragma will
47 effectively become a no-op. For convenience in what follows the
48 term I<UTF-X> is used to refer to UTF-8 on ASCII and ISO Latin based
49 platforms and UTF-EBCDIC on EBCDIC based platforms.
51 Enabling the C<utf8> pragma has the following effect:
57 Bytes in the source text that have their high-bit set will be treated
58 as being part of a literal UTF-8 character. This includes most
59 literals such as identifiers, string constants, constant regular
60 expression patterns and package names. On EBCDIC platforms characters
61 in the Latin 1 character set are treated as being part of a literal
66 Note that if you have bytes with the eighth bit on in your script
67 (for example embedded Latin-1 in your string literals), C<use utf8>
68 will be unhappy since the bytes are most probably not well-formed
69 UTF-8. If you want to have such bytes and use utf8, you can disable
70 utf8 until the end the block (or file, if at top level) by C<no utf8;>.
72 =head2 Utility functions
74 The following functions are defined in the C<utf8::> package by the perl core.
78 =item * $num_octets = utf8::upgrade($string);
80 Converts internal representation of string to the Perl's internal
81 I<UTF-X> form. Returns the number of octets necessary to represent
82 the string as I<UTF-X>.
84 =item * utf8::downgrade($string[, CHECK])
86 Converts internal representation of string to be un-encoded bytes.
88 =item * utf8::encode($string)
90 Converts (in-place) I<$string> from logical characters to octet sequence
91 representing it in Perl's I<UTF-X> encoding.
93 =item * $flag = utf8::decode($string)
95 Attempts to convert I<$string> in-place from Perl's I<UTF-X> encoding
96 into logical characters.
102 L<perlunicode>, L<bytes>