utf8(3)

NAME
utf8 - Perl pragma to enable/disable UTF-8 in source code

SYNOPSIS
    use utf8;
    no utf8;

DESCRIPTION
WARNING: The implementation of Unicode support in Perl is incomplete. See the perlunicode manpage for the exact details.

The "use utf8" pragma tells the Perl parser to allow UTF-8 in the program text in the current lexical scope. The "no utf8" pragma tells Perl to switch back to treating the source text as literal bytes in the current lexical scope.

This pragma is primarily a compatibility device. Perl versions earlier than 5.6 allowed arbitrary bytes in source code, whereas in future we would like to standardize on the UTF-8 encoding for source text. Until UTF-8 becomes the default format for source text, this pragma should be used to recognize UTF-8 in the source. When UTF-8 becomes the standard source format, this pragma will effectively become a no-op. This pragma already is a no-op on EBCDIC platforms (where it is alright to code perl in EBCDIC rather than UTF-8).

Enabling the "utf8" pragma has the following effects: Bytes in the source text that have their high-bit set will be treated as being part of a literal UTF-8 character. This includes most literals such as identifiers, string constants, constant regular expression patterns and package names. In the absence of inputs marked as UTF-8, regular expressions within the scope of this pragma will default to using character semantics instead of byte semantics.

    @bytes_or_chars = split //, $data;  # may split to bytes if data
                                        # $data isn't UTF-8
    {
        use utf8;                       # force char semantics
        @chars = split //, $data;       # splits characters
    }

SEE ALSO
the perlunicode manpage, the bytes manpage