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[SOLUTION]: Getting PGPLOT running on Windows XP

by BJ_Covert_Action (Beadle)
on Oct 08, 2010 at 17:22 UTC ( #864247=note: print w/replies, xml ) Need Help??

in reply to [SOLVED]: PDL and PGPLOT on Windows XP

Okay, so I figured out how to get PGPLOT running with strawberry perl 5.10.0 on a win32 system. As syphilis mentioned in his reply, Re^3: PDL and PGPLOT on Windows XP, the problem stemmed from having a module that was not working correctly. This file is located, typically, in the directory: C:\strawberry\perl\lib. In order to fix this problem I had to replace my default version of with a version that was built for strawberry perl 5.10.1. Now, there is probably a legitimate, effective way to do this by finding the appropriate source code somewhere on the strawberry perl website. However, I don't know where to find such things so, instead, I hacked together my own solution.

In order to get an appropriate build for for strawberry perl version 5.10.1, I downloaded the windows 32 installed for version found on the primary strawberry perl page. I then renamed my C:\strawberry directory on my local computer to C:\strawberry_0 so nothing would get overwritten. I proceeded to install version using the downloaded msi file. This created a new C:\strawberry directory on my computer, which I renamed C:\strawberry_5.10.1. I renamed the original strawberry directory (that I appended the _0 to the end of) back to C:\strawberry. I then proceeded to copy the C:\strawberry_5.10.1\perl\lib\ into C:\strawberry\perl\lib after renaming the original file located there to

Effectively, I replaced the DynaLoader perl module from the old build with one from the new build. All the renaming just allowed me to preserve all of my original copies in case something went horribly wrong. In order to save folks the trouble of going through this whole install process themselves, I decided to post the contents of my new, perl 5.10.1 file on this thread, below, so that you could just grab the source code from here if you want. If, instead, someone wants to point to another source of the perl code for perl 5.10.1, feel free to do so and I'll delete the source code from this thread to reduce redundancy. Hopefully someone will find this useful.


Click the "Read more..." section below for the source code.

# # $Id:,v 2.39 2009/11/26 09:23:48 dankogai Exp $ # package Encode; use strict; use warnings; our $VERSION = sprintf "%d.%02d", q$Revision: 2.39 $ =~ /(\d+)/g; sub DEBUG () { 0 } use XSLoader (); XSLoader::load( __PACKAGE__, $VERSION ); require Exporter; use base qw/Exporter/; # Public, encouraged API is exported by default our @EXPORT = qw( decode decode_utf8 encode encode_utf8 str2bytes bytes2str encodings find_encoding clone_encoding ); our @FB_FLAGS = qw( DIE_ON_ERR WARN_ON_ERR RETURN_ON_ERR LEAVE_SRC PERLQQ HTMLCREF XMLCREF STOP_AT_PARTIAL ); our @FB_CONSTS = qw( FB_DEFAULT FB_CROAK FB_QUIET FB_WARN FB_PERLQQ FB_HTMLCREF FB_XMLCREF ); our @EXPORT_OK = ( qw( _utf8_off _utf8_on define_encoding from_to is_16bit is_8bit is_utf8 perlio_ok resolve_alias utf8_downgrade utf8_upgrade ), @FB_FLAGS, @FB_CONSTS, ); our %EXPORT_TAGS = ( all => [ @EXPORT, @EXPORT_OK ], default => [ @EXPORT ], fallbacks => [ @FB_CONSTS ], fallback_all => [ @FB_CONSTS, @FB_FLAGS ], ); # Documentation moved after __END__ for speed - NI-S our $ON_EBCDIC = ( ord("A") == 193 ); use Encode::Alias; # Make a %Encoding package variable to allow a certain amount of cheat +ing our %Encoding; our %ExtModule; require Encode::Config; # See # # to find why sig handers inside eval{} are disabled. eval { local $SIG{__DIE__}; local $SIG{__WARN__}; require Encode::ConfigLocal; }; sub encodings { my $class = shift; my %enc; if ( @_ and $_[0] eq ":all" ) { %enc = ( %Encoding, %ExtModule ); } else { %enc = %Encoding; for my $mod ( map { m/::/o ? $_ : "Encode::$_" } @_ ) { DEBUG and warn $mod; for my $enc ( keys %ExtModule ) { $ExtModule{$enc} eq $mod and $enc{$enc} = $mod; } } } return sort { lc $a cmp lc $b } grep { !/^(?:Internal|Unicode|Guess)$/o } keys %enc; } sub perlio_ok { my $obj = ref( $_[0] ) ? $_[0] : find_encoding( $_[0] ); $obj->can("perlio_ok") and return $obj->perlio_ok(); return 0; # safety net } sub define_encoding { my $obj = shift; my $name = shift; $Encoding{$name} = $obj; my $lc = lc($name); define_alias( $lc => $obj ) unless $lc eq $name; while (@_) { my $alias = shift; define_alias( $alias, $obj ); } return $obj; } sub getEncoding { my ( $class, $name, $skip_external ) = @_; ref($name) && $name->can('renew') and return $name; exists $Encoding{$name} and return $Encoding{$name}; my $lc = lc $name; exists $Encoding{$lc} and return $Encoding{$lc}; my $oc = $class->find_alias($name); defined($oc) and return $oc; $lc ne $name and $oc = $class->find_alias($lc); defined($oc) and return $oc; unless ($skip_external) { if ( my $mod = $ExtModule{$name} || $ExtModule{$lc} ) { $mod =~ s,::,/,g; $mod .= '.pm'; eval { require $mod; }; exists $Encoding{$name} and return $Encoding{$name}; } } return; } sub find_encoding($;$) { my ( $name, $skip_external ) = @_; return __PACKAGE__->getEncoding( $name, $skip_external ); } sub resolve_alias($) { my $obj = find_encoding(shift); defined $obj and return $obj->name; return; } sub clone_encoding($) { my $obj = find_encoding(shift); ref $obj or return; eval { require Storable }; $@ and return; return Storable::dclone($obj); } sub encode($$;$) { my ( $name, $string, $check ) = @_; return undef unless defined $string; $string .= '' if ref $string; # stringify; $check ||= 0; unless ( defined $name ) { require Carp; Carp::croak("Encoding name should not be undef"); } my $enc = find_encoding($name); unless ( defined $enc ) { require Carp; Carp::croak("Unknown encoding '$name'"); } my $octets = $enc->encode( $string, $check ); $_[1] = $string if $check and !ref $check and !( $check & LEAVE_SR +C() ); return $octets; } *str2bytes = \&encode; sub decode($$;$) { my ( $name, $octets, $check ) = @_; return undef unless defined $octets; $octets .= '' if ref $octets; $check ||= 0; my $enc = find_encoding($name); unless ( defined $enc ) { require Carp; Carp::croak("Unknown encoding '$name'"); } my $string = $enc->decode( $octets, $check ); $_[1] = $octets if $check and !ref $check and !( $check & LEAVE_SR +C() ); return $string; } *bytes2str = \&decode; sub from_to($$$;$) { my ( $string, $from, $to, $check ) = @_; return undef unless defined $string; $check ||= 0; my $f = find_encoding($from); unless ( defined $f ) { require Carp; Carp::croak("Unknown encoding '$from'"); } my $t = find_encoding($to); unless ( defined $t ) { require Carp; Carp::croak("Unknown encoding '$to'"); } my $uni = $f->decode($string); $_[0] = $string = $t->encode( $uni, $check ); return undef if ( $check && length($uni) ); return defined( $_[0] ) ? length($string) : undef; } sub encode_utf8($) { my ($str) = @_; utf8::encode($str); return $str; } sub decode_utf8($;$) { my ( $str, $check ) = @_; return $str if is_utf8($str); if ($check) { return decode( "utf8", $str, $check ); } else { return decode( "utf8", $str ); return $str; } } predefine_encodings(1); # # This is to restore %Encoding if really needed; # sub predefine_encodings { require Encode::Encoding; no warnings 'redefine'; my $use_xs = shift; if ($ON_EBCDIC) { # was in Encode::UTF_EBCDIC package Encode::UTF_EBCDIC; push @Encode::UTF_EBCDIC::ISA, 'Encode::Encoding'; *decode = sub { my ( $obj, $str, $chk ) = @_; my $res = ''; for ( my $i = 0 ; $i < length($str) ; $i++ ) { $res .= chr( utf8::unicode_to_native( ord( substr( $str, $i, 1 +) ) ) ); } $_[1] = '' if $chk; return $res; }; *encode = sub { my ( $obj, $str, $chk ) = @_; my $res = ''; for ( my $i = 0 ; $i < length($str) ; $i++ ) { $res .= chr( utf8::native_to_unicode( ord( substr( $str, $i, 1 +) ) ) ); } $_[1] = '' if $chk; return $res; }; $Encode::Encoding{Unicode} = bless { Name => "UTF_EBCDIC" } => "Encode::UTF_EBCDIC"; } else { package Encode::Internal; push @Encode::Internal::ISA, 'Encode::Encoding'; *decode = sub { my ( $obj, $str, $chk ) = @_; utf8::upgrade($str); $_[1] = '' if $chk; return $str; }; *encode = \&decode; $Encode::Encoding{Unicode} = bless { Name => "Internal" } => "Encode::Internal"; } { # was in Encode::utf8 package Encode::utf8; push @Encode::utf8::ISA, 'Encode::Encoding'; # if ($use_xs) { Encode::DEBUG and warn __PACKAGE__, " XS on"; *decode = \&decode_xs; *encode = \&encode_xs; } else { Encode::DEBUG and warn __PACKAGE__, " XS off"; *decode = sub { my ( $obj, $octets, $chk ) = @_; my $str = Encode::decode_utf8($octets); if ( defined $str ) { $_[1] = '' if $chk; return $str; } return undef; }; *encode = sub { my ( $obj, $string, $chk ) = @_; my $octets = Encode::encode_utf8($string); $_[1] = '' if $chk; return $octets; }; } *cat_decode = sub { # ($obj, $dst, $src, $pos, $trm, $chk) # currently ignores $chk my ( $obj, undef, undef, $pos, $trm ) = @_; my ( $rdst, $rsrc, $rpos ) = \@_[ 1, 2, 3 ]; use bytes; if ( ( my $npos = index( $$rsrc, $trm, $pos ) ) >= 0 ) { $$rdst .= substr( $$rsrc, $pos, $npos - $pos + length($trm) ); $$rpos = $npos + length($trm); return 1; } $$rdst .= substr( $$rsrc, $pos ); $$rpos = length($$rsrc); return ''; }; $Encode::Encoding{utf8} = bless { Name => "utf8" } => "Encode::utf8"; $Encode::Encoding{"utf-8-strict"} = bless { Name => "utf-8-strict", strict_utf8 => 1 } => "Encode::utf8"; } } 1; __END__ =head1 NAME Encode - character encodings =head1 SYNOPSIS use Encode; =head2 Table of Contents Encode consists of a collection of modules whose details are too big to fit in one document. This POD itself explains the top-level APIs and general topics at a glance. For other topics and more details, see the PODs below: Name Description -------------------------------------------------------- Encode::Alias Alias definitions to encodings Encode::Encoding Encode Implementation Base Class Encode::Supported List of Supported Encodings Encode::CN Simplified Chinese Encodings Encode::JP Japanese Encodings Encode::KR Korean Encodings Encode::TW Traditional Chinese Encodings -------------------------------------------------------- =head1 DESCRIPTION The C<Encode> module provides the interfaces between Perl's strings and the rest of the system. Perl strings are sequences of B<characters>. The repertoire of characters that Perl can represent is at least that defined by the Unicode Consortium. On most platforms the ordinal values of the characters (as returned by C<ord(ch)>) is the "Unicode codepoint" for the character (the exceptions are those platforms where the legacy encoding is some variant of EBCDIC rather than a super-set of ASCII - see L<perlebcdic>). Traditionally, computer data has been moved around in 8-bit chunks often called "bytes". These chunks are also known as "octets" in networking standards. Perl is widely used to manipulate data of many types - not only strings of characters representing human or computer languages but also "binary" data being the machine's representation of numbers, pixels in an image - or just about anything. When Perl is processing "binary data", the programmer wants Perl to process "sequences of bytes". This is not a problem for Perl - as a byte has 256 possible values, it easily fits in Perl's much larger "logical character". =head2 TERMINOLOGY =over 2 =item * I<character>: a character in the range 0..(2**32-1) (or more). (What Perl's strings are made of.) =item * I<byte>: a character in the range 0..255 (A special case of a Perl character.) =item * I<octet>: 8 bits of data, with ordinal values 0..255 (Term for bytes passed to or from a non-Perl context, e.g. a disk file +.) =back =head1 PERL ENCODING API =over 2 =item $octets = encode(ENCODING, $string [, CHECK]) Encodes a string from Perl's internal form into I<ENCODING> and return +s a sequence of octets. ENCODING can be either a canonical name or an alias. For encoding names and aliases, see L</"Defining Aliases">. For CHECK, see L</"Handling Malformed Data">. For example, to convert a string from Perl's internal format to iso-8859-1 (also known as Latin1), $octets = encode("iso-8859-1", $string); B<CAVEAT>: When you run C<$octets = encode("utf8", $string)>, then $octets B<may not be equal to> $string. Though they both contain the same data, the UTF8 flag for $octets is B<always> off. When you encode anything, UTF8 flag of the result is always off, even when it contains completely valid utf8 string. See L</"The UTF8 flag"> below. If the $string is C<undef> then C<undef> is returned. =item $string = decode(ENCODING, $octets [, CHECK]) Decodes a sequence of octets assumed to be in I<ENCODING> into Perl's internal form and returns the resulting string. As in encode(), ENCODING can be either a canonical name or an alias. For encoding name +s and aliases, see L</"Defining Aliases">. For CHECK, see L</"Handling Malformed Data">. For example, to convert ISO-8859-1 data to a string in Perl's internal + format: $string = decode("iso-8859-1", $octets); B<CAVEAT>: When you run C<$string = decode("utf8", $octets)>, then $st +ring B<may not be equal to> $octets. Though they both contain the same dat +a, the UTF8 flag for $string is on unless $octets entirely consists of ASCII data (or EBCDIC on EBCDIC machines). See L</"The UTF8 flag"> below. If the $string is C<undef> then C<undef> is returned. =item [$obj =] find_encoding(ENCODING) Returns the I<encoding object> corresponding to ENCODING. Returns undef if no matching ENCODING is find. This object is what actually does the actual (en|de)coding. $utf8 = decode($name, $bytes); is in fact $utf8 = do{ $obj = find_encoding($name); croak qq(encoding "$name" not found) unless ref $obj; $obj->decode($bytes) }; with more error checking. Therefore you can save time by reusing this object as follows; my $enc = find_encoding("iso-8859-1"); while(<>){ my $utf8 = $enc->decode($_); # and do someting with $utf8; } Besides C<< ->decode >> and C<< ->encode >>, other methods are available as well. For instance, C<< -> name >> returns the canonical name of the encoding object. find_encoding("latin1")->name; # iso-8859-1 See L<Encode::Encoding> for details. =item [$length =] from_to($octets, FROM_ENC, TO_ENC [, CHECK]) Converts B<in-place> data between two encodings. The data in $octets must be encoded as octets and not as characters in Perl's internal format. For example, to convert ISO-8859-1 data to Microsoft's CP1250 encoding: from_to($octets, "iso-8859-1", "cp1250"); and to convert it back: from_to($octets, "cp1250", "iso-8859-1"); Note that because the conversion happens in place, the data to be converted cannot be a string constant; it must be a scalar variable. from_to() returns the length of the converted string in octets on success, I<undef> on error. B<CAVEAT>: The following operations look the same but are not quite so +; from_to($data, "iso-8859-1", "utf8"); #1 $data = decode("iso-8859-1", $data); #2 Both #1 and #2 make $data consist of a completely valid UTF-8 string but only #2 turns UTF8 flag on. #1 is equivalent to $data = encode("utf8", decode("iso-8859-1", $data)); See L</"The UTF8 flag"> below. Also note that from_to($octets, $from, $to, $check); is equivalent to $octets = encode($to, decode($from, $octets), $check); Yes, it does not respect the $check during decoding. It is deliberately done that way. If you need minute control, C<decode> then C<encode> as follows; $octets = encode($to, decode($from, $octets, $check_from), $check_to +); =item $octets = encode_utf8($string); Equivalent to C<$octets = encode("utf8", $string);> The characters that comprise $string are encoded in Perl's internal format and the result is returned as a sequence of octets. All possible characters have a UTF-8 representation so this function cannot fail. =item $string = decode_utf8($octets [, CHECK]); equivalent to C<$string = decode("utf8", $octets [, CHECK])>. The sequence of octets represented by $octets is decoded from UTF-8 into a sequence of logical characters. Not all sequences of octets form valid UTF-8 encodings, so it is possible for this call to fail. For CHECK, see L</"Handling Malformed Data">. =back =head2 Listing available encodings use Encode; @list = Encode->encodings(); Returns a list of the canonical names of the available encodings that are loaded. To get a list of all available encodings including the ones that are not loaded yet, say @all_encodings = Encode->encodings(":all"); Or you can give the name of a specific module. @with_jp = Encode->encodings("Encode::JP"); When "::" is not in the name, "Encode::" is assumed. @ebcdic = Encode->encodings("EBCDIC"); To find out in detail which encodings are supported by this package, see L<Encode::Supported>. =head2 Defining Aliases To add a new alias to a given encoding, use: use Encode; use Encode::Alias; define_alias(newName => ENCODING); After that, newName can be used as an alias for ENCODING. ENCODING may be either the name of an encoding or an I<encoding object> But before you do so, make sure the alias is nonexistent with C<resolve_alias()>, which returns the canonical name thereof. i.e. Encode::resolve_alias("latin1") eq "iso-8859-1" # true Encode::resolve_alias("iso-8859-12") # false; nonexistent Encode::resolve_alias($name) eq $name # true if $name is canonical resolve_alias() does not need C<use Encode::Alias>; it can be exported via C<use Encode qw(resolve_alias)>. See L<Encode::Alias> for details. =head2 Finding IANA Character Set Registry names The canonical name of a given encoding does not necessarily agree with IANA IANA Character Set Registry, commonly seen as C<< Content-Type: text/plain; charset=I<whatever> >>. For most cases canonical names work but sometimes it does not (notably 'utf-8-strict'). Therefore as of Encode version 2.21, a new method C<mime_name()> is ad +ded. use Encode; my $enc = find_encoding('UTF-8'); warn $enc->name; # utf-8-strict warn $enc->mime_name; # UTF-8 See also: L<Encode::Encoding> =head1 Encoding via PerlIO If your perl supports I<PerlIO> (which is the default), you can use a PerlIO layer to decode and encode directly via a filehandle. The following two examples are totally identical in their functionality. # via PerlIO open my $in, "<:encoding(shiftjis)", $infile or die; open my $out, ">:encoding(euc-jp)", $outfile or die; while(<$in>){ print $out $_; } # via from_to open my $in, "<", $infile or die; open my $out, ">", $outfile or die; while(<$in>){ from_to($_, "shiftjis", "euc-jp", 1); print $out $_; } Unfortunately, it may be that encodings are PerlIO-savvy. You can che +ck if your encoding is supported by PerlIO by calling the C<perlio_ok> method. Encode::perlio_ok("hz"); # False find_encoding("euc-cn")->perlio_ok; # True where PerlIO is availabl +e use Encode qw(perlio_ok); # exported upon request perlio_ok("euc-jp") Fortunately, all encodings that come with Encode core are PerlIO-savvy except for hz and ISO-2022-kr. For gory details, see L<Encode::Encoding> and L<Encode::PerlIO>. =head1 Handling Malformed Data The optional I<CHECK> argument tells Encode what to do when it encounters malformed data. Without CHECK, Encode::FB_DEFAULT ( == 0 ) is assumed. As of version 2.12 Encode supports coderef values for CHECK. See belo +w. =over 2 =item B<NOTE:> Not all encoding support this feature Some encodings ignore I<CHECK> argument. For example, L<Encode::Unicode> ignores I<CHECK> and it always croaks on error. =back Now here is the list of I<CHECK> values available =over 2 =item I<CHECK> = Encode::FB_DEFAULT ( == 0) If I<CHECK> is 0, (en|de)code will put a I<substitution character> in place of a malformed character. When you encode, E<lt>subcharE<gt> will be used. When you decode the code point C<0xFFFD> is used. If the data is supposed to be UTF-8, an optional lexical warning (category utf8) is given. =item I<CHECK> = Encode::FB_CROAK ( == 1) If I<CHECK> is 1, methods will die on error immediately with an error message. Therefore, when I<CHECK> is set to 1, you should trap the error with eval{} unless you really want to let it die. =item I<CHECK> = Encode::FB_QUIET If I<CHECK> is set to Encode::FB_QUIET, (en|de)code will immediately return the portion of the data that has been processed so far when an error occurs. The data argument will be overwritten with everything after that point (that is, the unprocessed part of data). This is handy when you have to call decode repeatedly in the case where your source data may contain partial multi-byte character sequences, (i.e. you are reading with a fixed-width buffer). Here is a sample code that does exactly this: my $buffer = ''; my $string = ''; while(read $fh, $buffer, 256, length($buffer)){ $string .= decode($encoding, $buffer, Encode::FB_QUIET); # $buffer now contains the unprocessed partial character } =item I<CHECK> = Encode::FB_WARN This is the same as above, except that it warns on error. Handy when you are debugging the mode above. =item perlqq mode (I<CHECK> = Encode::FB_PERLQQ) =item HTML charref mode (I<CHECK> = Encode::FB_HTMLCREF) =item XML charref mode (I<CHECK> = Encode::FB_XMLCREF) For encodings that are implemented by Encode::XS, CHECK == Encode::FB_PERLQQ turns (en|de)code into C<perlqq> fallback mode. When you decode, C<\xI<HH>> will be inserted for a malformed character +, where I<HH> is the hex representation of the octet that could not be decoded to utf8. And when you encode, C<\x{I<HHHH>}> will be inserted +, where I<HHHH> is the Unicode ID of the character that cannot be found in the character repertoire of the encoding. HTML/XML character reference modes are about the same, in place of C<\x{I<HHHH>}>, HTML uses C<&#I<NNN>;> where I<NNN> is a decimal numbe +r and XML uses C<&#xI<HHHH>;> where I<HHHH> is the hexadecimal number. In Encode 2.10 or later, C<LEAVE_SRC> is also implied. =item The bitmask These modes are actually set via a bitmask. Here is how the FB_XX constants are laid out. You can import the FB_XX constants via C<use Encode qw(:fallbacks)>; you can import the generic bitmask constants via C<use Encode qw(:fallback_all)>. FB_DEFAULT FB_CROAK FB_QUIET FB_WARN FB_PERLQQ DIE_ON_ERR 0x0001 X WARN_ON_ERR 0x0002 X RETURN_ON_ERR 0x0004 X X LEAVE_SRC 0x0008 X PERLQQ 0x0100 X HTMLCREF 0x0200 XMLCREF 0x0400 =back =over 2 =item Encode::LEAVE_SRC If the C<Encode::LEAVE_SRC> bit is not set, but I<CHECK> is, then the +second argument to C<encode()> or C<decode()> may be assigned to by the funct +ions. If you're not interested in this, then bitwise-or the bitmask with it. =back =head2 coderef for CHECK As of Encode 2.12 CHECK can also be a code reference which takes the ord value of unmapped caharacter as an argument and returns a string that represents the fallback character. For instance, $ascii = encode("ascii", $utf8, sub{ sprintf "<U+%04X>", shift }); Acts like FB_PERLQQ but E<lt>U+I<XXXX>E<gt> is used instead of \x{I<XXXX>}. =head1 Defining Encodings To define a new encoding, use: use Encode qw(define_encoding); define_encoding($object, 'canonicalName' [, alias...]); I<canonicalName> will be associated with I<$object>. The object should provide the interface described in L<Encode::Encoding>. If more than two arguments are provided then additional arguments are taken as aliases for I<$object>. See L<Encode::Encoding> for more details. =head1 The UTF8 flag Before the introduction of Unicode support in perl, The C<eq> operator just compared the strings represented by two scalars. Beginning with perl 5.8, C<eq> compares two strings with simultaneous consideration o +f I<the UTF8 flag>. To explain why we made it so, I will quote page 402 +of C<Programming Perl, 3rd ed.> =over 2 =item Goal #1: Old byte-oriented programs should not spontaneously break on the old byte-oriented data they used to work on. =item Goal #2: Old byte-oriented programs should magically start working on the new character-oriented data when appropriate. =item Goal #3: Programs should run just as fast in the new character-oriented mode as in the old byte-oriented mode. =item Goal #4: Perl should remain one language, rather than forking into a byte-oriented Perl and a character-oriented Perl. =back Back when C<Programming Perl, 3rd ed.> was written, not even Perl 5.6. +0 was born and many features documented in the book remained unimplemented for a long time. Perl 5.8 corrected this and the introd +uction of the UTF8 flag is one of them. You can think of this perl notion as + of a byte-oriented mode (UTF8 flag off) and a character-oriented mode (UTF8 flag on). Here is how Encode takes care of the UTF8 flag. =over 2 =item * When you encode, the resulting UTF8 flag is always off. =item * When you decode, the resulting UTF8 flag is on unless you can unambiguously represent data. Here is the definition of dis-ambiguity. After C<$utf8 = decode('foo', $octet);>, When $octet is... The UTF8 flag in $utf8 is --------------------------------------------- In ASCII only (or EBCDIC only) OFF In ISO-8859-1 ON In any other Encoding ON --------------------------------------------- As you see, there is one exception, In ASCII. That way you can assume Goal #1. And with Encode Goal #2 is assumed but you still have to be careful in such cases mentioned in B<CAVEAT> paragraphs. This UTF8 flag is not visible in perl scripts, exactly for the same reason you cannot (or you I<don't have to>) see if a scalar contains a string, integer, or floating point number. But you can still peek and poke these if you will. See the section below. =back =head2 Messing with Perl's Internals The following API uses parts of Perl's internals in the current implementation. As such, they are efficient but may change. =over 2 =item is_utf8(STRING [, CHECK]) [INTERNAL] Tests whether the UTF8 flag is turned on in the STRING. If CHECK is true, also checks the data in STRING for being well-formed UTF-8. Returns true if successful, false otherwise. As of perl 5.8.1, L<utf8> also has utf8::is_utf8(). =item _utf8_on(STRING) [INTERNAL] Turns on the UTF8 flag in STRING. The data in STRING is B<not> checked for being well-formed UTF-8. Do not use unless you B<know> that the STRING is well-formed UTF-8. Returns the previous state of the UTF8 flag (so please don't treat the return value as indicating success or failure), or C<undef> if STRING is not a string. This function does not work on tainted values. =item _utf8_off(STRING) [INTERNAL] Turns off the UTF8 flag in STRING. Do not use frivolously. Returns the previous state of the UTF8 flag (so please don't treat the return value as indicating success or failure), or C<undef> if STRING +is not a string. This function does not work on tainted values. =back =head1 UTF-8 vs. utf8 vs. UTF8 ....We now view strings not as sequences of bytes, but as sequences of numbers in the range 0 .. 2**32-1 (or in the case of 64-bit computers, 0 .. 2**64-1) -- Programming Perl, 3rd ed. That has been the perl's notion of UTF-8 but official UTF-8 is more strict; Its ranges is much narrower (0 .. 10FFFF), some sequences are not allowed (i.e. Those used in the surrogate pair, 0xFFFE, et al). Now that is overruled by Larry Wall himself. From: Larry Wall <> Date: December 04, 2004 11:51:58 JST To: Subject: Re: Make support the real UTF-8 Message-Id: <> On Fri, Dec 03, 2004 at 10:12:12PM +0000, Tim Bunce wrote: : I've no problem with 'utf8' being perl's unrestricted uft8 encodin +g, : but "UTF-8" is the name of the standard and should give the : corresponding behaviour. For what it's worth, that's how I've always kept them straight in my head. Also for what it's worth, Perl 6 will mostly default to strict but make it easy to switch back to lax. Larry Do you copy? As of Perl 5.8.7, B<UTF-8> means strict, official UTF-8 while B<utf8> means liberal, lax, version thereof. And Encode version 2.10 or later thus groks the difference between C<UTF-8> and C"utf8". encode("utf8", "\x{FFFF_FFFF}", 1); # okay encode("UTF-8", "\x{FFFF_FFFF}", 1); # croaks C<UTF-8> in Encode is actually a canonical name for C<utf-8-strict>. Yes, the hyphen between "UTF" and "8" is important. Without it Encode goes "liberal" find_encoding("UTF-8")->name # is 'utf-8-strict' find_encoding("utf-8")->name # ditto. names are case insensitive find_encoding("utf_8")->name # ditto. "_" are treated as "-" find_encoding("UTF8")->name # is 'utf8'. The UTF8 flag is internally called UTF8, without a hyphen. It indicate +s whether a string is internally encoded as utf8, also without a hypen. =head1 SEE ALSO L<Encode::Encoding>, L<Encode::Supported>, L<Encode::PerlIO>, L<encoding>, L<perlebcdic>, L<perlfunc/open>, L<perlunicode>, L<perluniintro>, L<perlunifaq>, L<perlunitut> L<utf8>, the Perl Unicode Mailing List E<lt>perl-unicode@perl.orgE<gt> =head1 MAINTAINER This project was originated by Nick Ing-Simmons and later maintained by Dan Kogai E<lt><gt>. See AUTHORS for a full list of people involved. For any questions, use E<lt>perl-unicode@perl.orgE<gt> so we can all share. While Dan Kogai retains the copyright as a maintainer, the credit should go to all those involoved. See AUTHORS for those submitted codes. =head1 COPYRIGHT Copyright 2002-2006 Dan Kogai E<lt><gt> This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =cut

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