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.\" Automatically generated by Pod::Man 2.25 (Pod::Simple 3.20) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is turned on, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .ie \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . nr % 0 . rr F .\} .el \{\ . de IX .. .\} .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "utf8 3" .TH utf8 3 "2013-03-04" "perl v5.16.3" "Perl Programmers Reference Guide" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" utf8 \- Perl pragma to enable/disable UTF\-8 (or UTF\-EBCDIC) in source code .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 2 \& use utf8; \& no utf8; \& \& # Convert the internal representation of a Perl scalar to/from UTF\-8. \& \& $num_octets = utf8::upgrade($string); \& $success = utf8::downgrade($string[, FAIL_OK]); \& \& # Change each character of a Perl scalar to/from a series of \& # characters that represent the UTF\-8 bytes of each original character. \& \& utf8::encode($string); # "\ex{100}" becomes "\exc4\ex80" \& utf8::decode($string); # "\exc4\ex80" becomes "\ex{100}" \& \& $flag = utf8::is_utf8(STRING); # since Perl 5.8.1 \& $flag = utf8::valid(STRING); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" The \f(CW\*(C`use utf8\*(C'\fR pragma tells the Perl parser to allow \s-1UTF\-8\s0 in the program text in the current lexical scope (allow UTF-EBCDIC on \s-1EBCDIC\s0 based platforms). The \f(CW\*(C`no utf8\*(C'\fR pragma tells Perl to switch back to treating the source text as literal bytes in the current lexical scope. .PP \&\fBDo not use this pragma for anything else than telling Perl that your script is written in \s-1UTF\-8\s0.\fR The utility functions described below are directly usable without \f(CW\*(C`use utf8;\*(C'\fR. .PP Because it is not possible to reliably tell \s-1UTF\-8\s0 from native 8 bit encodings, you need either a Byte Order Mark at the beginning of your source code, or \f(CW\*(C`use utf8;\*(C'\fR, to instruct perl. .PP When \s-1UTF\-8\s0 becomes the standard source format, this pragma will effectively become a no-op. For convenience in what follows the term \&\fIUTF-X\fR is used to refer to \s-1UTF\-8\s0 on \s-1ASCII\s0 and \s-1ISO\s0 Latin based platforms and UTF-EBCDIC on \s-1EBCDIC\s0 based platforms. .PP See also the effects of the \f(CW\*(C`\-C\*(C'\fR switch and its cousin, the \&\f(CW$ENV{PERL_UNICODE}\fR, in perlrun. .PP Enabling the \f(CW\*(C`utf8\*(C'\fR pragma has the following effect: .IP "\(bu" 4 Bytes in the source text that have their high-bit set will be treated as being part of a literal UTF-X sequence. This includes most literals such as identifier names, string constants, and constant regular expression patterns. .Sp On \s-1EBCDIC\s0 platforms characters in the Latin 1 character set are treated as being part of a literal UTF-EBCDIC character. .PP Note that if you have bytes with the eighth bit on in your script (for example embedded Latin\-1 in your string literals), \f(CW\*(C`use utf8\*(C'\fR will be unhappy since the bytes are most probably not well-formed UTF-X. If you want to have such bytes under \f(CW\*(C`use utf8\*(C'\fR, you can disable this pragma until the end the block (or file, if at top level) by \&\f(CW\*(C`no utf8;\*(C'\fR. .SS "Utility functions" .IX Subsection "Utility functions" The following functions are defined in the \f(CW\*(C`utf8::\*(C'\fR package by the Perl core. You do not need to say \f(CW\*(C`use utf8\*(C'\fR to use these and in fact you should not say that unless you really want to have \s-1UTF\-8\s0 source code. .IP "\(bu" 4 \&\f(CW$num_octets\fR = utf8::upgrade($string) .Sp Converts in-place the internal representation of the string from an octet sequence in the native encoding (Latin\-1 or \s-1EBCDIC\s0) to \fIUTF-X\fR. The logical character sequence itself is unchanged. If \fI\f(CI$string\fI\fR is already stored as \fIUTF-X\fR, then this is a no-op. Returns the number of octets necessary to represent the string as \fIUTF-X\fR. Can be used to make sure that the \s-1UTF\-8\s0 flag is on, so that \f(CW\*(C`\ew\*(C'\fR or \f(CW\*(C`lc()\*(C'\fR work as Unicode on strings containing characters in the range 0x80\-0xFF (on \s-1ASCII\s0 and derivatives). .Sp \&\fBNote that this function does not handle arbitrary encodings.\fR Therefore Encode is recommended for the general purposes; see also Encode. .IP "\(bu" 4 \&\f(CW$success\fR = utf8::downgrade($string[, \s-1FAIL_OK\s0]) .Sp Converts in-place the internal representation of the string from \&\fIUTF-X\fR to the equivalent octet sequence in the native encoding (Latin\-1 or \s-1EBCDIC\s0). The logical character sequence itself is unchanged. If \&\fI\f(CI$string\fI\fR is already stored as native 8 bit, then this is a no-op. Can be used to make sure that the \s-1UTF\-8\s0 flag is off, e.g. when you want to make sure that the \fIsubstr()\fR or \fIlength()\fR function works with the usually faster byte algorithm. .Sp Fails if the original \fIUTF-X\fR sequence cannot be represented in the native 8 bit encoding. On failure dies or, if the value of \f(CW\*(C`FAIL_OK\*(C'\fR is true, returns false. .Sp Returns true on success. .Sp \&\fBNote that this function does not handle arbitrary encodings.\fR Therefore Encode is recommended for the general purposes; see also Encode. .IP "\(bu" 4 utf8::encode($string) .Sp Converts in-place the character sequence to the corresponding octet sequence in \fIUTF-X\fR. That is, every (possibly wide) character gets replaced with a sequence of one or more characters that represent the individual \fIUTF-X\fR bytes of the character. The \s-1UTF8\s0 flag is turned off. Returns nothing. .Sp .Vb 2 \& my $a = "\ex{100}"; # $a contains one character, with ord 0x100 \& utf8::encode($a); # $a contains two characters, with ords 0xc4 and 0x80 .Ve .Sp \&\fBNote that this function does not handle arbitrary encodings.\fR Therefore Encode is recommended for the general purposes; see also Encode. .IP "\(bu" 4 \&\f(CW$success\fR = utf8::decode($string) .Sp Attempts to convert in-place the octet sequence in \fIUTF-X\fR 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 \s-1UTF\-8\s0 flag is turned on only if the source string contains multiple-byte \fIUTF-X\fR characters. If \fI\f(CI$string\fI\fR is invalid as \fIUTF-X\fR, returns false; otherwise returns true. .Sp .Vb 2 \& my $a = "\exc4\ex80"; # $a contains two characters, with ords 0xc4 and 0x80 \& utf8::decode($a); # $a contains one character, with ord 0x100 .Ve .Sp \&\fBNote that this function does not handle arbitrary encodings.\fR Therefore Encode is recommended for the general purposes; see also Encode. .IP "\(bu" 4 \&\f(CW$flag\fR = utf8::is_utf8(\s-1STRING\s0) .Sp (Since Perl 5.8.1) Test whether \s-1STRING\s0 is in \s-1UTF\-8\s0 internally. Functionally the same as \fIEncode::is_utf8()\fR. .IP "\(bu" 4 \&\f(CW$flag\fR = utf8::valid(\s-1STRING\s0) .Sp [\s-1INTERNAL\s0] Test whether \s-1STRING\s0 is in a consistent state regarding \&\s-1UTF\-8\s0. Will return true is well-formed \s-1UTF\-8\s0 and has the \s-1UTF\-8\s0 flag on \fBor\fR 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 \fIutf8::is_utf8()\fR instead. .PP \&\f(CW\*(C`utf8::encode\*(C'\fR is like \f(CW\*(C`utf8::upgrade\*(C'\fR, but the \s-1UTF8\s0 flag is cleared. See perlunicode for more on the \s-1UTF8\s0 flag and the C \s-1API\s0 functions \f(CW\*(C`sv_utf8_upgrade\*(C'\fR, \f(CW\*(C`sv_utf8_downgrade\*(C'\fR, \f(CW\*(C`sv_utf8_encode\*(C'\fR, and \f(CW\*(C`sv_utf8_decode\*(C'\fR, which are wrapped by the Perl functions \&\f(CW\*(C`utf8::upgrade\*(C'\fR, \f(CW\*(C`utf8::downgrade\*(C'\fR, \f(CW\*(C`utf8::encode\*(C'\fR and \&\f(CW\*(C`utf8::decode\*(C'\fR. Also, the functions utf8::is_utf8, utf8::valid, utf8::encode, utf8::decode, utf8::upgrade, and utf8::downgrade are actually internal, and thus always available, without a \f(CW\*(C`require utf8\*(C'\fR statement. .SH "BUGS" .IX Header "BUGS" One can have Unicode in identifier names, but not in package/class or subroutine names. While some limited functionality towards this does exist as of Perl 5.8.0, that is more accidental than designed; use of Unicode for the said purposes is unsupported. .PP One reason of this unfinishedness is its (currently) inherent unportability: since both package names and subroutine names may need to be mapped to file and directory names, the Unicode capability of the filesystem becomes important\*(-- and there unfortunately aren't portable answers. .SH "SEE ALSO" .IX Header "SEE ALSO" perlunitut, perluniintro, perlrun, bytes, perlunicode