+On EBCDIC platforms characters in the Latin 1 character set are
+treated as being part of a literal UTF-EBCDIC character.
+
+=back
+
+Note that if you have bytes with the eighth bit on in your script
+(for example embedded Latin-1 in your string literals), C<use utf8>
+will be unhappy since the bytes are most probably not well-formed
+UTF-X. If you want to have such bytes under C<use utf8>, you can disable
+this pragma until the end the block (or file, if at top level) by
+C<no utf8;>.
+
+=head2 Utility functions
+
+The following functions are defined in the C<utf8::> package by the
+Perl core. You do not need to say C<use utf8> to use these and in fact
+you should not say that unless you really want to have UTF-8 source code.
+
+=over 4
+
+=item * $num_octets = utf8::upgrade($string)
+
+Converts in-place the internal representation of the string from an octet
+sequence in the native encoding (Latin-1 or EBCDIC) to I<UTF-X>. The
+logical character sequence itself is unchanged. If I<$string> is already
+stored as I<UTF-X>, then this is a no-op. Returns the
+number of octets necessary to represent the string as I<UTF-X>. Can be
+used to make sure that the UTF-8 flag is on, so that C<\w> or C<lc()>
+work as Unicode on strings containing characters in the range 0x80-0xFF
+(on ASCII and derivatives).
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * $success = utf8::downgrade($string[, FAIL_OK])
+
+Converts in-place the the internal representation of the string from
+I<UTF-X> to the equivalent octet sequence in the native encoding (Latin-1
+or EBCDIC). The logical character sequence itself is unchanged. If
+I<$string> is already stored as native 8 bit, then this is a no-op. Can
+be used to
+make sure that the UTF-8 flag is off, e.g. when you want to make sure
+that the substr() or length() function works with the usually faster
+byte algorithm.
+
+Fails if the original I<UTF-X> sequence cannot be represented in the
+native 8 bit encoding. On failure dies or, if the value of C<FAIL_OK> is
+true, returns false.
+
+Returns true on success.
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * utf8::encode($string)
+
+Converts in-place the character sequence to the corresponding octet
+sequence in I<UTF-X>. That is, every (possibly wide) character gets
+replaced with a sequence of one or more characters that represent the
+individual I<UTF-X> bytes of the character. The UTF8 flag is turned off.
+Returns nothing.
+
+ my $a = "\x{100}"; # $a contains one character, with ord 0x100
+ utf8::encode($a); # $a contains two characters, with ords 0xc4 and 0x80
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * $success = utf8::decode($string)
+
+Attempts to convert in-place the octet sequence in I<UTF-X> to the
+corresponding character sequence. That is, it replaces each sequence of
+characters in the string whose ords represent a valid UTF-X byte
+sequence, with the corresponding single character. The UTF-8 flag is
+turned on only if the source string contains multiple-byte I<UTF-X>
+characters. If I<$string> is invalid as I<UTF-X>, returns false;
+otherwise returns true.
+
+ my $a = "\xc4\x80"; # $a contains two characters, with ords 0xc4 and 0x80
+ utf8::decode($a); # $a contains one character, with ord 0x100
+
+B<Note that this function does not handle arbitrary encodings.>
+Therefore Encode is recommended for the general purposes; see also
+L<Encode>.
+
+=item * $flag = utf8::is_utf8(STRING)
+
+(Since Perl 5.8.1) Test whether STRING is in UTF-8 internally.
+Functionally the same as Encode::is_utf8().
+
+=item * $flag = utf8::valid(STRING)
+
+[INTERNAL] Test whether STRING is in a consistent state regarding
+UTF-8. Will return true is well-formed UTF-8 and has the UTF-8 flag
+on B<or> if string is held as bytes (both these states are 'consistent').
+Main reason for this routine is to allow Perl's testsuite to check
+that operations have left strings in a consistent state. You most
+probably want to use utf8::is_utf8() instead.