Adding upstream version 4.22.0.upstream/4.22.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2906 insertions, 0 deletions

diff --git a/upstream/fedora-40/man1/perl58delta.1 b/upstream/fedora-40/man1/perl58delta.1
new file mode 100644
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--- /dev/null
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@@ -0,0 +1,2906 @@
+.\" -*- mode: troff; coding: utf-8 -*-
+.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43)
+.\"
+.\" 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
+..
+.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>.
+.ie n \{\
+.    ds C` ""
+.    ds C' ""
+'br\}
+.el\{\
+.    ds C`
+.    ds C'
+'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 >0, 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.
+.\"
+.\" Avoid warning from groff about undefined register 'F'.
+.de IX
+..
+.nr rF 0
+.if \n(.g .if rF .nr rF 1
+.if (\n(rF:(\n(.g==0)) \{\
+.    if \nF \{\
+.        de IX
+.        tm Index:\\$1\t\\n%\t"\\$2"
+..
+.        if !\nF==2 \{\
+.            nr % 0
+.            nr F 2
+.        \}
+.    \}
+.\}
+.rr rF
+.\" ========================================================================
+.\"
+.IX Title "PERL58DELTA 1"
+.TH PERL58DELTA 1 2024-01-25 "perl v5.38.2" "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
+perl58delta \- what is new for perl v5.8.0
+.SH DESCRIPTION
+.IX Header "DESCRIPTION"
+This document describes differences between the 5.6.0 release and
+the 5.8.0 release.
+.PP
+Many of the bug fixes in 5.8.0 were already seen in the 5.6.1
+maintenance release since the two releases were kept closely
+coordinated (while 5.8.0 was still called 5.7.something).
+.PP
+Changes that were integrated into the 5.6.1 release are marked \f(CW\*(C`[561]\*(C'\fR.
+Many of these changes have been further developed since 5.6.1 was released,
+those are marked \f(CW\*(C`[561+]\*(C'\fR.
+.PP
+You can see the list of changes in the 5.6.1 release (both from the
+5.005_03 release and the 5.6.0 release) by reading perl561delta.
+.SH "Highlights In 5.8.0"
+.IX Header "Highlights In 5.8.0"
+.IP \(bu 4
+Better Unicode support
+.IP \(bu 4
+New IO Implementation
+.IP \(bu 4
+New Thread Implementation
+.IP \(bu 4
+Better Numeric Accuracy
+.IP \(bu 4
+Safe Signals
+.IP \(bu 4
+Many New Modules
+.IP \(bu 4
+More Extensive Regression Testing
+.SH "Incompatible Changes"
+.IX Header "Incompatible Changes"
+.SS "Binary Incompatibility"
+.IX Subsection "Binary Incompatibility"
+\&\fBPerl 5.8 is not binary compatible with earlier releases of Perl.\fR
+.PP
+\&\fBYou have to recompile your XS modules.\fR
+.PP
+(Pure Perl modules should continue to work.)
+.PP
+The major reason for the discontinuity is the new IO architecture
+called PerlIO.  PerlIO is the default configuration because without
+it many new features of Perl 5.8 cannot be used.  In other words:
+you just have to recompile your modules containing XS code, sorry
+about that.
+.PP
+In future releases of Perl, non-PerlIO aware XS modules may become
+completely unsupported.  This shouldn't be too difficult for module
+authors, however: PerlIO has been designed as a drop-in replacement
+(at the source code level) for the stdio interface.
+.PP
+Depending on your platform, there are also other reasons why
+we decided to break binary compatibility, please read on.
+.SS "64\-bit platforms and malloc"
+.IX Subsection "64-bit platforms and malloc"
+If your pointers are 64 bits wide, the Perl malloc is no longer being
+used because it does not work well with 8\-byte pointers.  Also,
+usually the system mallocs on such platforms are much better optimized
+for such large memory models than the Perl malloc.  Some memory-hungry
+Perl applications like the PDL don't work well with Perl's malloc.
+Finally, other applications than Perl (such as mod_perl) tend to prefer
+the system malloc.  Such platforms include Alpha and 64\-bit HPPA,
+MIPS, PPC, and Sparc.
+.SS "AIX Dynaloading"
+.IX Subsection "AIX Dynaloading"
+The AIX dynaloading now uses in AIX releases 4.3 and newer the native
+dlopen interface of AIX instead of the old emulated interface.  This
+change will probably break backward compatibility with compiled
+modules.  The change was made to make Perl more compliant with other
+applications like mod_perl which are using the AIX native interface.
+.ie n .SS "Attributes for ""my"" variables now handled at run-time"
+.el .SS "Attributes for \f(CWmy\fP variables now handled at run-time"
+.IX Subsection "Attributes for my variables now handled at run-time"
+The \f(CW\*(C`my EXPR : ATTRS\*(C'\fR syntax now applies variable attributes at
+run-time.  (Subroutine and \f(CW\*(C`our\*(C'\fR variables still get attributes applied
+at compile-time.)  See attributes for additional details.  In particular,
+however, this allows variable attributes to be useful for \f(CW\*(C`tie\*(C'\fR interfaces,
+which was a deficiency of earlier releases.  Note that the new semantics
+doesn't work with the Attribute::Handlers module (as of version 0.76).
+.SS "Socket Extension Dynamic in VMS"
+.IX Subsection "Socket Extension Dynamic in VMS"
+The Socket extension is now dynamically loaded instead of being
+statically built in.  This may or may not be a problem with ancient
+TCP/IP stacks of VMS: we do not know since we weren't able to test
+Perl in such configurations.
+.SS "IEEE-format Floating Point Default on OpenVMS Alpha"
+.IX Subsection "IEEE-format Floating Point Default on OpenVMS Alpha"
+Perl now uses IEEE format (T_FLOAT) as the default internal floating
+point format on OpenVMS Alpha, potentially breaking binary compatibility
+with external libraries or existing data.  G_FLOAT is still available as
+a configuration option.  The default on VAX (D_FLOAT) has not changed.
+.ie n .SS "New Unicode Semantics (no more ""use utf8"", almost)"
+.el .SS "New Unicode Semantics (no more \f(CWuse utf8\fP, almost)"
+.IX Subsection "New Unicode Semantics (no more use utf8, almost)"
+Previously in Perl 5.6 to use Unicode one would say "use utf8" and
+then the operations (like string concatenation) were Unicode-aware
+in that lexical scope.
+.PP
+This was found to be an inconvenient interface, and in Perl 5.8 the
+Unicode model has completely changed: now the "Unicodeness" is bound
+to the data itself, and for most of the time "use utf8" is not needed
+at all.  The only remaining use of "use utf8" is when the Perl script
+itself has been written in the UTF\-8 encoding of Unicode.  (UTF\-8 has
+not been made the default since there are many Perl scripts out there
+that are using various national eight-bit character sets, which would
+be illegal in UTF\-8.)
+.PP
+See perluniintro for the explanation of the current model,
+and utf8 for the current use of the utf8 pragma.
+.SS "New Unicode Properties"
+.IX Subsection "New Unicode Properties"
+Unicode \fIscripts\fR are now supported. Scripts are similar to (and superior
+to) Unicode \fIblocks\fR. The difference between scripts and blocks is that
+scripts are the glyphs used by a language or a group of languages, while
+the blocks are more artificial groupings of (mostly) 256 characters based
+on the Unicode numbering.
+.PP
+In general, scripts are more inclusive, but not universally so. For
+example, while the script \f(CW\*(C`Latin\*(C'\fR includes all the Latin characters and
+their various diacritic-adorned versions, it does not include the various
+punctuation or digits (since they are not solely \f(CW\*(C`Latin\*(C'\fR).
+.PP
+A number of other properties are now supported, including \f(CW\*(C`\ep{L&}\*(C'\fR,
+\&\f(CW\*(C`\ep{Any}\*(C'\fR \f(CW\*(C`\ep{Assigned}\*(C'\fR, \f(CW\*(C`\ep{Unassigned}\*(C'\fR, \f(CW\*(C`\ep{Blank}\*(C'\fR [561] and
+\&\f(CW\*(C`\ep{SpacePerl}\*(C'\fR [561] (along with their \f(CW\*(C`\eP{...}\*(C'\fR versions, of course).
+See perlunicode for details, and more additions.
+.PP
+The \f(CW\*(C`In\*(C'\fR or \f(CW\*(C`Is\*(C'\fR prefix to names used with the \f(CW\*(C`\ep{...}\*(C'\fR and \f(CW\*(C`\eP{...}\*(C'\fR
+are now almost always optional. The only exception is that a \f(CW\*(C`In\*(C'\fR prefix
+is required to signify a Unicode block when a block name conflicts with a
+script name. For example, \f(CW\*(C`\ep{Tibetan}\*(C'\fR refers to the script, while
+\&\f(CW\*(C`\ep{InTibetan}\*(C'\fR refers to the block. When there is no name conflict, you
+can omit the \f(CW\*(C`In\*(C'\fR from the block name (e.g. \f(CW\*(C`\ep{BraillePatterns}\*(C'\fR), but
+to be safe, it's probably best to always use the \f(CW\*(C`In\*(C'\fR).
+.SS "REF(...) Instead Of SCALAR(...)"
+.IX Subsection "REF(...) Instead Of SCALAR(...)"
+A reference to a reference now stringifies as "REF(0x81485ec)" instead
+of "SCALAR(0x81485ec)" in order to be more consistent with the return
+value of \fBref()\fR.
+.SS "pack/unpack D/F recycled"
+.IX Subsection "pack/unpack D/F recycled"
+The undocumented pack/unpack template letters D/F have been recycled
+for better use: now they stand for long double (if supported by the
+platform) and NV (Perl internal floating point type).  (They used
+to be aliases for d/f, but you never knew that.)
+.SS "\fBglob()\fP now returns filenames in alphabetical order"
+.IX Subsection "glob() now returns filenames in alphabetical order"
+The list of filenames from \fBglob()\fR (or <...>) is now by default sorted
+alphabetically to be csh-compliant (which is what happened before
+in most Unix platforms).  (\fBbsd_glob()\fR does still sort platform
+natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) [561]
+.SS Deprecations
+.IX Subsection "Deprecations"
+.IP \(bu 4
+The semantics of bless(REF, REF) were unclear and until someone proves
+it to make some sense, it is forbidden.
+.IP \(bu 4
+The obsolete chat2 library that should never have been allowed
+to escape the laboratory has been decommissioned.
+.IP \(bu 4
+Using chdir("") or chdir(undef) instead of explicit \fBchdir()\fR is
+doubtful.  A failure (think chdir(\fBsome_function()\fR) can lead into
+unintended \fBchdir()\fR to the home directory, therefore this behaviour
+is deprecated.
+.IP \(bu 4
+The builtin \fBdump()\fR function has probably outlived most of its
+usefulness.  The core-dumping functionality will remain in future
+available as an explicit call to \f(CWCORE::dump()\fR, but in future
+releases the behaviour of an unqualified \f(CWdump()\fR call may change.
+.IP \(bu 4
+The very dusty examples in the eg/ directory have been removed.
+Suggestions for new shiny examples welcome but the main issue is that
+the examples need to be documented, tested and (most importantly)
+maintained.
+.IP \(bu 4
+The (bogus) escape sequences \e8 and \e9 now give an optional warning
+("Unrecognized escape passed through").  There is no need to \e\-escape
+any \f(CW\*(C`\ew\*(C'\fR character.
+.IP \(bu 4
+The *glob{FILEHANDLE} is deprecated, use *glob{IO} instead.
+.IP \(bu 4
+The \f(CW\*(C`package;\*(C'\fR syntax (\f(CW\*(C`package\*(C'\fR without an argument) has been
+deprecated.  Its semantics were never that clear and its
+implementation even less so.  If you have used that feature to
+disallow all but fully qualified variables, \f(CW\*(C`use strict;\*(C'\fR instead.
+.IP \(bu 4
+The unimplemented POSIX regex features [[.cc.]] and [[=c=]] are still
+recognised but now cause fatal errors.  The previous behaviour of
+ignoring them by default and warning if requested was unacceptable
+since it, in a way, falsely promised that the features could be used.
+.IP \(bu 4
+In future releases, non-PerlIO aware XS modules may become completely
+unsupported.  Since PerlIO is a drop-in replacement for stdio at the
+source code level, this shouldn't be that drastic a change.
+.IP \(bu 4
+Previous versions of perl and some readings of some sections of Camel
+III implied that the \f(CW\*(C`:raw\*(C'\fR "discipline" was the inverse of \f(CW\*(C`:crlf\*(C'\fR.
+Turning off "clrfness" is no longer enough to make a stream truly
+binary. So the PerlIO \f(CW\*(C`:raw\*(C'\fR layer (or "discipline", to use the Camel
+book's older terminology) is now formally defined as being equivalent
+to binmode(FH) \- which is in turn defined as doing whatever is
+necessary to pass each byte as-is without any translation.  In
+particular binmode(FH) \- and hence \f(CW\*(C`:raw\*(C'\fR \- will now turn off both
+CRLF and UTF\-8 translation and remove other layers (e.g. :\fBencoding()\fR)
+which would modify byte stream.
+.IP \(bu 4
+The current user-visible implementation of pseudo-hashes (the weird
+use of the first array element) is deprecated starting from Perl 5.8.0
+and will be removed in Perl 5.10.0, and the feature will be
+implemented differently.  Not only is the current interface rather
+ugly, but the current implementation slows down normal array and hash
+use quite noticeably. The \f(CW\*(C`fields\*(C'\fR pragma interface will remain
+available.  The \fIrestricted hashes\fR interface is expected to
+be the replacement interface (see Hash::Util).  If your existing
+programs depends on the underlying implementation, consider using
+Class::PseudoHash from CPAN.
+.IP \(bu 4
+The syntaxes \f(CW\*(C`@a\->[...]\*(C'\fR and  \f(CW\*(C`%h\->{...}\*(C'\fR have now been deprecated.
+.IP \(bu 4
+After years of trying, suidperl is considered to be too complex to
+ever be considered truly secure.  The suidperl functionality is likely
+to be removed in a future release.
+.IP \(bu 4
+The 5.005 threads model (module \f(CW\*(C`Thread\*(C'\fR) is deprecated and expected
+to be removed in Perl 5.10.  Multithreaded code should be migrated to
+the new ithreads model (see threads, threads::shared and
+perlthrtut).
+.IP \(bu 4
+The long deprecated uppercase aliases for the string comparison
+operators (EQ, NE, LT, LE, GE, GT) have now been removed.
+.IP \(bu 4
+The tr///C and tr///U features have been removed and will not return;
+the interface was a mistake.  Sorry about that.  For similar
+functionality, see pack('U0', ...) and pack('C0', ...). [561]
+.IP \(bu 4
+Earlier Perls treated "sub foo (@bar)" as equivalent to "sub foo (@)".
+The prototypes are now checked better at compile-time for invalid
+syntax.  An optional warning is generated ("Illegal character in
+prototype...")  but this may be upgraded to a fatal error in a future
+release.
+.IP \(bu 4
+The \f(CW\*(C`exec LIST\*(C'\fR and \f(CW\*(C`system LIST\*(C'\fR operations now produce warnings on
+tainted data and in some future release they will produce fatal errors.
+.IP \(bu 4
+The existing behaviour when localising tied arrays and hashes is wrong,
+and will be changed in a future release, so do not rely on the existing
+behaviour. See "Localising Tied Arrays and Hashes Is Broken".
+.SH "Core Enhancements"
+.IX Header "Core Enhancements"
+.SS "Unicode Overhaul"
+.IX Subsection "Unicode Overhaul"
+Unicode in general should be now much more usable than in Perl 5.6.0
+(or even in 5.6.1).  Unicode can be used in hash keys, Unicode in
+regular expressions should work now, Unicode in tr/// should work now,
+Unicode in I/O should work now.  See perluniintro for introduction
+and perlunicode for details.
+.IP \(bu 4
+The Unicode Character Database coming with Perl has been upgraded
+to Unicode 3.2.0.  For more information, see http://www.unicode.org/ .
+[561+] (5.6.1 has UCD 3.0.1.)
+.IP \(bu 4
+For developers interested in enhancing Perl's Unicode capabilities:
+almost all the UCD files are included with the Perl distribution in
+the \fIlib/unicore\fR subdirectory.  The most notable omission, for space
+considerations, is the Unihan database.
+.IP \(bu 4
+The properties \ep{Blank} and \ep{SpacePerl} have been added. "Blank" is like
+C \fBisblank()\fR, that is, it contains only "horizontal whitespace" (the space
+character is, the newline isn't), and the "SpacePerl" is the Unicode
+equivalent of \f(CW\*(C`\es\*(C'\fR (\ep{Space} isn't, since that includes the vertical
+tabulator character, whereas \f(CW\*(C`\es\*(C'\fR doesn't.)
+.Sp
+See "New Unicode Properties" earlier in this document for additional
+information on changes with Unicode properties.
+.SS "PerlIO is Now The Default"
+.IX Subsection "PerlIO is Now The Default"
+.IP \(bu 4
+IO is now by default done via PerlIO rather than system's "stdio".
+PerlIO allows "layers" to be "pushed" onto a file handle to alter the
+handle's behaviour.  Layers can be specified at open time via 3\-arg
+form of open:
+.Sp
+.Vb 1
+\&   open($fh,\*(Aq>:crlf :utf8\*(Aq, $path) || ...
+.Ve
+.Sp
+or on already opened handles via extended \f(CW\*(C`binmode\*(C'\fR:
+.Sp
+.Vb 1
+\&   binmode($fh,\*(Aq:encoding(iso\-8859\-7)\*(Aq);
+.Ve
+.Sp
+The built-in layers are: unix (low level read/write), stdio (as in
+previous Perls), perlio (re-implementation of stdio buffering in a
+portable manner), crlf (does CRLF <=> "\en" translation as on Win32,
+but available on any platform).  A mmap layer may be available if
+platform supports it (mostly Unixes).
+.Sp
+Layers to be applied by default may be specified via the 'open' pragma.
+.Sp
+See "Installation and Configuration Improvements" for the effects
+of PerlIO on your architecture name.
+.IP \(bu 4
+If your platform supports \fBfork()\fR, you can use the list form of \f(CW\*(C`open\*(C'\fR
+for pipes.  For example:
+.Sp
+.Vb 1
+\&    open KID_PS, "\-|", "ps", "aux" or die $!;
+.Ve
+.Sp
+forks the \fBps\fR\|(1) command (without spawning a shell, as there are more
+than three arguments to \fBopen()\fR), and reads its standard output via the
+\&\f(CW\*(C`KID_PS\*(C'\fR filehandle.  See perlipc.
+.IP \(bu 4
+File handles can be marked as accepting Perl's internal encoding of Unicode
+(UTF\-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" :
+.Sp
+.Vb 1
+\&   open($fh,">:utf8","Uni.txt");
+.Ve
+.Sp
+Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named
+for you since it's not UTF\-8 what you will be getting but instead
+UTF-EBCDIC.  See perlunicode, utf8, and
+http://www.unicode.org/reports/tr16/ for more information.
+In future releases this naming may change.  See perluniintro
+for more information about UTF\-8.
+.IP \(bu 4
+If your environment variables (LC_ALL, LC_CTYPE, LANG) look like you
+want to use UTF\-8 (any of the variables match \f(CW\*(C`/utf\-?8/i\*(C'\fR), your
+STDIN, STDOUT, STDERR handles and the default open layer (see open)
+are marked as UTF\-8.  (This feature, like other new features that
+combine Unicode and I/O, work only if you are using PerlIO, but that's
+the default.)
+.Sp
+Note that after this Perl really does assume that everything is UTF\-8:
+for example if some input handle is not, Perl will probably very soon
+complain about the input data like this "Malformed UTF\-8 ..." since
+any old eight-bit data is not legal UTF\-8.
+.Sp
+Note for code authors: if you want to enable your users to use UTF\-8
+as their default encoding  but in your code still have eight-bit I/O streams
+(such as images or zip files), you need to explicitly \fBopen()\fR or \fBbinmode()\fR
+with \f(CW\*(C`:bytes\*(C'\fR (see "open" in perlfunc and "binmode" in perlfunc), or you
+can just use \f(CWbinmode(FH)\fR (nice for pre\-5.8.0 backward compatibility).
+.IP \(bu 4
+File handles can translate character encodings from/to Perl's internal
+Unicode form on read/write via the ":\fBencoding()\fR" layer.
+.IP \(bu 4
+File handles can be opened to "in memory" files held in Perl scalars via:
+.Sp
+.Vb 1
+\&   open($fh,\*(Aq>\*(Aq, \e$variable) || ...
+.Ve
+.IP \(bu 4
+Anonymous temporary files are available without need to
+\&'use FileHandle' or other module via
+.Sp
+.Vb 1
+\&   open($fh,"+>", undef) || ...
+.Ve
+.Sp
+That is a literal undef, not an undefined value.
+.SS ithreads
+.IX Subsection "ithreads"
+The new interpreter threads ("ithreads" for short) implementation of
+multithreading, by Arthur Bergman, replaces the old "5.005 threads"
+implementation.  In the ithreads model any data sharing between
+threads must be explicit, as opposed to the model where data sharing
+was implicit.  See threads and threads::shared, and
+perlthrtut.
+.PP
+As a part of the ithreads implementation Perl will also use
+any necessary and detectable reentrant libc interfaces.
+.SS "Restricted Hashes"
+.IX Subsection "Restricted Hashes"
+A restricted hash is restricted to a certain set of keys, no keys
+outside the set can be added.  Also individual keys can be restricted
+so that the key cannot be deleted and the value cannot be changed.
+No new syntax is involved: the Hash::Util module is the interface.
+.SS "Safe Signals"
+.IX Subsection "Safe Signals"
+Perl used to be fragile in that signals arriving at inopportune moments
+could corrupt Perl's internal state.  Now Perl postpones handling of
+signals until it's safe (between opcodes).
+.PP
+This change may have surprising side effects because signals no longer
+interrupt Perl instantly.  Perl will now first finish whatever it was
+doing, like finishing an internal operation (like \fBsort()\fR) or an
+external operation (like an I/O operation), and only then look at any
+arrived signals (and before starting the next operation).  No more corrupt
+internal state since the current operation is always finished first,
+but the signal may take more time to get heard.  Note that breaking
+out from potentially blocking operations should still work, though.
+.SS "Understanding of Numbers"
+.IX Subsection "Understanding of Numbers"
+In general a lot of fixing has happened in the area of Perl's
+understanding of numbers, both integer and floating point.  Since in
+many systems the standard number parsing functions like \f(CWstrtoul()\fR
+and \f(CWatof()\fR seem to have bugs, Perl tries to work around their
+deficiencies.  This results hopefully in more accurate numbers.
+.PP
+Perl now tries internally to use integer values in numeric conversions
+and basic arithmetics (+ \- * /) if the arguments are integers, and
+tries also to keep the results stored internally as integers.
+This change leads to often slightly faster and always less lossy
+arithmetics. (Previously Perl always preferred floating point numbers
+in its math.)
+.SS "Arrays now always interpolate into double-quoted strings [561]"
+.IX Subsection "Arrays now always interpolate into double-quoted strings [561]"
+In double-quoted strings, arrays now interpolate, no matter what.  The
+behavior in earlier versions of perl 5 was that arrays would interpolate
+into strings if the array had been mentioned before the string was
+compiled, and otherwise Perl would raise a fatal compile-time error.
+In versions 5.000 through 5.003, the error was
+.PP
+.Vb 1
+\&        Literal @example now requires backslash
+.Ve
+.PP
+In versions 5.004_01 through 5.6.0, the error was
+.PP
+.Vb 1
+\&        In string, @example now must be written as \e@example
+.Ve
+.PP
+The idea here was to get people into the habit of writing
+\&\f(CW"fred\e@example.com"\fR when they wanted a literal \f(CW\*(C`@\*(C'\fR sign, just as
+they have always written \f(CW"Give me back my \e$5"\fR when they wanted a
+literal \f(CW\*(C`$\*(C'\fR sign.
+.PP
+Starting with 5.6.1, when Perl now sees an \f(CW\*(C`@\*(C'\fR sign in a
+double-quoted string, it \fIalways\fR attempts to interpolate an array,
+regardless of whether or not the array has been used or declared
+already.  The fatal error has been downgraded to an optional warning:
+.PP
+.Vb 1
+\&        Possible unintended interpolation of @example in string
+.Ve
+.PP
+This warns you that \f(CW"fred@example.com"\fR is going to turn into
+\&\f(CW\*(C`fred.com\*(C'\fR if you don't backslash the \f(CW\*(C`@\*(C'\fR.
+See http://perl.plover.com/at\-error.html for more details
+about the history here.
+.SS "Miscellaneous Changes"
+.IX Subsection "Miscellaneous Changes"
+.IP \(bu 4
+AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute
+to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value.
+.IP \(bu 4
+The \f(CW$Config\fR{byteorder} (and corresponding BYTEORDER in config.h) was
+previously wrong in platforms if sizeof(long) was 4, but sizeof(IV)
+was 8.  The byteorder was only sizeof(long) bytes long (1234 or 4321),
+but now it is correctly sizeof(IV) bytes long, (12345678 or 87654321).
+(This problem didn't affect Windows platforms.)
+.Sp
+Also, \f(CW$Config\fR{byteorder} is now computed dynamically\-\-this is more
+robust with "fat binaries" where an executable image contains binaries
+for more than one binary platform, and when cross-compiling.
+.IP \(bu 4
+\&\f(CW\*(C`perl \-d:Module=arg,arg,arg\*(C'\fR now works (previously one couldn't pass
+in multiple arguments.)
+.IP \(bu 4
+\&\f(CW\*(C`do\*(C'\fR followed by a bareword now ensures that this bareword isn't
+a keyword (to avoid a bug where \f(CW\*(C`do q(foo.pl)\*(C'\fR tried to call a
+subroutine called \f(CW\*(C`q\*(C'\fR).  This means that for example instead of
+\&\f(CW\*(C`do format()\*(C'\fR you must write \f(CW\*(C`do &format()\*(C'\fR.
+.IP \(bu 4
+The builtin \fBdump()\fR now gives an optional warning
+\&\f(CW\*(C`dump() better written as CORE::dump()\*(C'\fR,
+meaning that by default \f(CWdump(...)\fR is resolved as the builtin
+\&\fBdump()\fR which dumps core and aborts, not as (possibly) user-defined
+\&\f(CW\*(C`sub dump\*(C'\fR.  To call the latter, qualify the call as \f(CW&dump(...)\fR.
+(The whole \fBdump()\fR feature is to considered deprecated, and possibly
+removed/changed in future releases.)
+.IP \(bu 4
+\&\fBchomp()\fR and \fBchop()\fR are now overridable.  Note, however, that their
+prototype (as given by \f(CWprototype("CORE::chomp")\fR is undefined,
+because it cannot be expressed and therefore one cannot really write
+replacements to override these builtins.
+.IP \(bu 4
+END blocks are now run even if you exit/die in a BEGIN block.
+Internally, the execution of END blocks is now controlled by
+PL_exit_flags & PERL_EXIT_DESTRUCT_END. This enables the new
+behaviour for Perl embedders. This will default in 5.10. See
+perlembed.
+.IP \(bu 4
+Formats now support zero-padded decimal fields.
+.IP \(bu 4
+Although "you shouldn't do that", it was possible to write code that
+depends on Perl's hashed key order (Data::Dumper does this).  The new
+algorithm "One-at-a-Time" produces a different hashed key order.
+More details are in "Performance Enhancements".
+.IP \(bu 4
+lstat(FILEHANDLE) now gives a warning because the operation makes no sense.
+In future releases this may become a fatal error.
+.IP \(bu 4
+Spurious syntax errors generated in certain situations, when \fBglob()\fR
+caused File::Glob to be loaded for the first time, have been fixed. [561]
+.IP \(bu 4
+Lvalue subroutines can now return \f(CW\*(C`undef\*(C'\fR in list context.  However,
+the lvalue subroutine feature still remains experimental.  [561+]
+.IP \(bu 4
+A lost warning "Can't declare ... dereference in my" has been
+restored (Perl had it earlier but it became lost in later releases.)
+.IP \(bu 4
+A new special regular expression variable has been introduced:
+\&\f(CW$^N\fR, which contains the most-recently closed group (submatch).
+.IP \(bu 4
+\&\f(CW\*(C`no Module;\*(C'\fR does not produce an error even if Module does not have an
+\&\fBunimport()\fR method.  This parallels the behavior of \f(CW\*(C`use\*(C'\fR vis-a-vis
+\&\f(CW\*(C`import\*(C'\fR. [561]
+.IP \(bu 4
+The numerical comparison operators return \f(CW\*(C`undef\*(C'\fR if either operand
+is a NaN.  Previously the behaviour was unspecified.
+.IP \(bu 4
+\&\f(CW\*(C`our\*(C'\fR can now have an experimental optional attribute \f(CW\*(C`unique\*(C'\fR that
+affects how global variables are shared among multiple interpreters,
+see "our" in perlfunc.
+.IP \(bu 4
+The following builtin functions are now overridable: \fBeach()\fR, \fBkeys()\fR,
+\&\fBpop()\fR, \fBpush()\fR, \fBshift()\fR, \fBsplice()\fR, \fBunshift()\fR. [561]
+.IP \(bu 4
+\&\f(CW\*(C`pack() / unpack()\*(C'\fR can now group template letters with \f(CW\*(C`()\*(C'\fR and then
+apply repetition/count modifiers on the groups.
+.IP \(bu 4
+\&\f(CW\*(C`pack() / unpack()\*(C'\fR can now process the Perl internal numeric types:
+IVs, UVs, NVs\-\- and also long doubles, if supported by the platform.
+The template letters are \f(CW\*(C`j\*(C'\fR, \f(CW\*(C`J\*(C'\fR, \f(CW\*(C`F\*(C'\fR, and \f(CW\*(C`D\*(C'\fR.
+.IP \(bu 4
+\&\f(CW\*(C`pack(\*(AqU0a*\*(Aq, ...)\*(C'\fR can now be used to force a string to UTF\-8.
+.IP \(bu 4
+my _\|_PACKAGE_\|_ \f(CW$obj\fR now works. [561]
+.IP \(bu 4
+\&\fBPOSIX::sleep()\fR now returns the number of \fIunslept\fR seconds
+(as the POSIX standard says), as opposed to \fBCORE::sleep()\fR which
+returns the number of slept seconds.
+.IP \(bu 4
+\&\fBprintf()\fR and \fBsprintf()\fR now support parameter reordering using the
+\&\f(CW\*(C`%\ed+\e$\*(C'\fR and \f(CW\*(C`*\ed+\e$\*(C'\fR syntaxes.  For example
+.Sp
+.Vb 1
+\&    printf "%2\e$s %1\e$s\en", "foo", "bar";
+.Ve
+.Sp
+will print "bar foo\en".  This feature helps in writing
+internationalised software, and in general when the order
+of the parameters can vary.
+.IP \(bu 4
+The (\e&) prototype now works properly. [561]
+.IP \(bu 4
+prototype(\e[$@%&]) is now available to implicitly create references
+(useful for example if you want to emulate the \fBtie()\fR interface).
+.IP \(bu 4
+A new command-line option, \f(CW\*(C`\-t\*(C'\fR is available.  It is the
+little brother of \f(CW\*(C`\-T\*(C'\fR: instead of dying on taint violations,
+lexical warnings are given.  \fBThis is only meant as a temporary
+debugging aid while securing the code of old legacy applications.
+This is not a substitute for \-T.\fR
+.IP \(bu 4
+In other taint news, the \f(CW\*(C`exec LIST\*(C'\fR and \f(CW\*(C`system LIST\*(C'\fR have now been
+considered too risky (think \f(CW\*(C`exec @ARGV\*(C'\fR: it can start any program
+with any arguments), and now the said forms cause a warning under
+lexical warnings.  You should carefully launder the arguments to
+guarantee their validity.  In future releases of Perl the forms will
+become fatal errors so consider starting laundering now.
+.IP \(bu 4
+Tied hash interfaces are now required to have the EXISTS and DELETE
+methods (either own or inherited).
+.IP \(bu 4
+If tr/// is just counting characters, it doesn't attempt to
+modify its target.
+.IP \(bu 4
+\&\fBuntie()\fR will now call an \fBUNTIE()\fR hook if it exists.  See perltie
+for details. [561]
+.IP \(bu 4
+"utime" in perlfunc now supports \f(CW\*(C`utime undef, undef, @files\*(C'\fR to change the
+file timestamps to the current time.
+.IP \(bu 4
+The rules for allowing underscores (underbars) in numeric constants
+have been relaxed and simplified: now you can have an underscore
+simply \fBbetween digits\fR.
+.IP \(bu 4
+Rather than relying on C's argv[0] (which may not contain a full pathname)
+where possible $^X is now set by asking the operating system.
+(eg by reading \fI/proc/self/exe\fR on Linux, \fI/proc/curproc/file\fR on FreeBSD)
+.IP \(bu 4
+A new variable, \f(CW\*(C`${^TAINT}\*(C'\fR, indicates whether taint mode is enabled.
+.IP \(bu 4
+You can now override the \fBreadline()\fR builtin, and this overrides also
+the <FILEHANDLE> angle bracket operator.
+.IP \(bu 4
+The command-line options \-s and \-F are now recognized on the shebang
+(#!) line.
+.IP \(bu 4
+Use of the \f(CW\*(C`/c\*(C'\fR match modifier without an accompanying \f(CW\*(C`/g\*(C'\fR modifier
+elicits a new warning: \f(CW\*(C`Use of /c modifier is meaningless without /g\*(C'\fR.
+.Sp
+Use of \f(CW\*(C`/c\*(C'\fR in substitutions, even with \f(CW\*(C`/g\*(C'\fR, elicits
+\&\f(CW\*(C`Use of /c modifier is meaningless in s///\*(C'\fR.
+.Sp
+Use of \f(CW\*(C`/g\*(C'\fR with \f(CW\*(C`split\*(C'\fR elicits \f(CW\*(C`Use of /g modifier is meaningless
+in split\*(C'\fR.
+.IP \(bu 4
+Support for the \f(CW\*(C`CLONE\*(C'\fR special subroutine had been added.
+With ithreads, when a new thread is created, all Perl data is cloned,
+however non-Perl data cannot be cloned automatically.  In \f(CW\*(C`CLONE\*(C'\fR you
+can do whatever you need to do, like for example handle the cloning of
+non-Perl data, if necessary.  \f(CW\*(C`CLONE\*(C'\fR will be executed once for every
+package that has it defined or inherited.  It will be called in the
+context of the new thread, so all modifications are made in the new area.
+.Sp
+See perlmod
+.SH "Modules and Pragmata"
+.IX Header "Modules and Pragmata"
+.SS "New Modules and Pragmata"
+.IX Subsection "New Modules and Pragmata"
+.IP \(bu 4
+\&\f(CW\*(C`Attribute::Handlers\*(C'\fR, originally by Damian Conway and now maintained
+by Arthur Bergman, allows a class to define attribute handlers.
+.Sp
+.Vb 3
+\&    package MyPack;
+\&    use Attribute::Handlers;
+\&    sub Wolf :ATTR(SCALAR) { print "howl!\en" }
+\&
+\&    # later, in some package using or inheriting from MyPack...
+\&
+\&    my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
+.Ve
+.Sp
+Both variables and routines can have attribute handlers.  Handlers can
+be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the
+exact compilation phase (BEGIN, CHECK, INIT, or END).
+See Attribute::Handlers.
+.IP \(bu 4
+\&\f(CW\*(C`B::Concise\*(C'\fR, by Stephen McCamant, is a new compiler backend for
+walking the Perl syntax tree, printing concise info about ops.
+The output is highly customisable.  See B::Concise. [561+]
+.IP \(bu 4
+The new bignum, bigint, and bigrat pragmas, by Tels, implement
+transparent bignum support (using the Math::BigInt, Math::BigFloat,
+and Math::BigRat backends).
+.IP \(bu 4
+\&\f(CW\*(C`Class::ISA\*(C'\fR, by Sean Burke, is a module for reporting the search
+path for a class's ISA tree.  See Class::ISA.
+.IP \(bu 4
+\&\f(CW\*(C`Cwd\*(C'\fR now has a split personality: if possible, an XS extension is
+used, (this will hopefully be faster, more secure, and more robust)
+but if not possible, the familiar Perl implementation is used.
+.IP \(bu 4
+\&\f(CW\*(C`Devel::PPPort\*(C'\fR, originally by Kenneth Albanowski and now
+maintained by Paul Marquess, has been added.  It is primarily used
+by \f(CW\*(C`h2xs\*(C'\fR to enhance portability of XS modules between different
+versions of Perl.  See Devel::PPPort.
+.IP \(bu 4
+\&\f(CW\*(C`Digest\*(C'\fR, frontend module for calculating digests (checksums), from
+Gisle Aas, has been added.  See Digest.
+.IP \(bu 4
+\&\f(CW\*(C`Digest::MD5\*(C'\fR for calculating MD5 digests (checksums) as defined in
+RFC 1321, from Gisle Aas, has been added.  See Digest::MD5.
+.Sp
+.Vb 1
+\&    use Digest::MD5 \*(Aqmd5_hex\*(Aq;
+\&
+\&    $digest = md5_hex("Thirsty Camel");
+\&
+\&    print $digest, "\en"; # 01d19d9d2045e005c3f1b80e8b164de1
+.Ve
+.Sp
+NOTE: the \f(CW\*(C`MD5\*(C'\fR backward compatibility module is deliberately not
+included since its further use is discouraged.
+.Sp
+See also PerlIO::via::QuotedPrint.
+.IP \(bu 4
+\&\f(CW\*(C`Encode\*(C'\fR, originally by Nick Ing-Simmons and now maintained by Dan
+Kogai, provides a mechanism to translate between different character
+encodings.  Support for Unicode, ISO\-8859\-1, and ASCII are compiled in
+to the module.  Several other encodings (like the rest of the
+ISO\-8859, CP*/Win*, Mac, KOI8\-R, three variants EBCDIC, Chinese,
+Japanese, and Korean encodings) are included and can be loaded at
+runtime.  (For space considerations, the largest Chinese encodings
+have been separated into their own CPAN module, Encode::HanExtra,
+which Encode will use if available).  See Encode.
+.Sp
+Any encoding supported by Encode module is also available to the
+":\fBencoding()\fR" layer if PerlIO is used.
+.IP \(bu 4
+\&\f(CW\*(C`Hash::Util\*(C'\fR is the interface to the new \fIrestricted hashes\fR
+feature.  (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
+Michael Schwern.)  See Hash::Util.
+.IP \(bu 4
+\&\f(CW\*(C`I18N::Langinfo\*(C'\fR can be used to query locale information.
+See I18N::Langinfo.
+.IP \(bu 4
+\&\f(CW\*(C`I18N::LangTags\*(C'\fR, by Sean Burke, has functions for dealing with
+RFC3066\-style language tags.  See I18N::LangTags.
+.IP \(bu 4
+\&\f(CW\*(C`ExtUtils::Constant\*(C'\fR, by Nicholas Clark, is a new tool for extension
+writers for generating XS code to import C header constants.
+See ExtUtils::Constant.
+.IP \(bu 4
+\&\f(CW\*(C`Filter::Simple\*(C'\fR, by Damian Conway, is an easy-to-use frontend to
+Filter::Util::Call.  See Filter::Simple.
+.Sp
+.Vb 1
+\&    # in MyFilter.pm:
+\&
+\&    package MyFilter;
+\&
+\&    use Filter::Simple sub {
+\&        while (my ($from, $to) = splice @_, 0, 2) {
+\&                s/$from/$to/g;
+\&        }
+\&    };
+\&
+\&    1;
+\&
+\&    # in user\*(Aqs code:
+\&
+\&    use MyFilter qr/red/ => \*(Aqgreen\*(Aq;
+\&
+\&    print "red\en";   # this code is filtered, will print "green\en"
+\&    print "bored\en"; # this code is filtered, will print "bogreen\en"
+\&
+\&    no MyFilter;
+\&
+\&    print "red\en";   # this code is not filtered, will print "red\en"
+.Ve
+.IP \(bu 4
+\&\f(CW\*(C`File::Temp\*(C'\fR, by Tim Jenness, allows one to create temporary files
+and directories in an easy, portable, and secure way.  See File::Temp.
+[561+]
+.IP \(bu 4
+\&\f(CW\*(C`Filter::Util::Call\*(C'\fR, by Paul Marquess, provides you with the
+framework to write \fIsource filters\fR in Perl.  For most uses, the
+frontend Filter::Simple is to be preferred.  See Filter::Util::Call.
+.IP \(bu 4
+\&\f(CW\*(C`if\*(C'\fR, by Ilya Zakharevich, is a new pragma for conditional inclusion
+of modules.
+.IP \(bu 4
+libnet, by Graham Barr, is a collection of perl5 modules related
+to network programming.  See Net::FTP, Net::NNTP, Net::Ping
+(not part of libnet, but related), Net::POP3, Net::SMTP,
+and Net::Time.
+.Sp
+Perl installation leaves libnet unconfigured; use \fIlibnetcfg\fR
+to configure it.
+.IP \(bu 4
+\&\f(CW\*(C`List::Util\*(C'\fR, by Graham Barr, is a selection of general-utility
+list subroutines, such as \fBsum()\fR, \fBmin()\fR, \fBfirst()\fR, and \fBshuffle()\fR.
+See List::Util.
+.IP \(bu 4
+\&\f(CW\*(C`Locale::Constants\*(C'\fR, \f(CW\*(C`Locale::Country\*(C'\fR, \f(CW\*(C`Locale::Currency\*(C'\fR
+\&\f(CW\*(C`Locale::Language\*(C'\fR, and Locale::Script, by Neil Bowers, have
+been added.  They provide the codes for various locale standards, such
+as "fr" for France, "usd" for US Dollar, and "ja" for Japanese.
+.Sp
+.Vb 1
+\&    use Locale::Country;
+\&
+\&    $country = code2country(\*(Aqjp\*(Aq);               # $country gets \*(AqJapan\*(Aq
+\&    $code    = country2code(\*(AqNorway\*(Aq);           # $code gets \*(Aqno\*(Aq
+.Ve
+.Sp
+See Locale::Constants, Locale::Country, Locale::Currency,
+and Locale::Language.
+.IP \(bu 4
+\&\f(CW\*(C`Locale::Maketext\*(C'\fR, by Sean Burke, is a localization framework.  See
+Locale::Maketext, and Locale::Maketext::TPJ13.  The latter is an
+article about software localization, originally published in The Perl
+Journal #13, and republished here with kind permission.
+.IP \(bu 4
+\&\f(CW\*(C`Math::BigRat\*(C'\fR for big rational numbers, to accompany Math::BigInt and
+Math::BigFloat, from Tels.  See Math::BigRat.
+.IP \(bu 4
+\&\f(CW\*(C`Memoize\*(C'\fR can make your functions faster by trading space for time,
+from Mark-Jason Dominus.  See Memoize.
+.IP \(bu 4
+\&\f(CW\*(C`MIME::Base64\*(C'\fR, by Gisle Aas, allows you to encode data in base64,
+as defined in RFC 2045 \- \fIMIME (Multipurpose Internet Mail
+Extensions)\fR.
+.Sp
+.Vb 1
+\&    use MIME::Base64;
+\&
+\&    $encoded = encode_base64(\*(AqAladdin:open sesame\*(Aq);
+\&    $decoded = decode_base64($encoded);
+\&
+\&    print $encoded, "\en"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
+.Ve
+.Sp
+See MIME::Base64.
+.IP \(bu 4
+\&\f(CW\*(C`MIME::QuotedPrint\*(C'\fR, by Gisle Aas, allows you to encode data
+in quoted-printable encoding, as defined in RFC 2045 \- \fIMIME
+(Multipurpose Internet Mail Extensions)\fR.
+.Sp
+.Vb 1
+\&    use MIME::QuotedPrint;
+\&
+\&    $encoded = encode_qp("\exDE\exAD\exBE\exEF");
+\&    $decoded = decode_qp($encoded);
+\&
+\&    print $encoded, "\en"; # "=DE=AD=BE=EF\en"
+\&    print $decoded, "\en"; # "\exDE\exAD\exBE\exEF\en"
+.Ve
+.Sp
+See also PerlIO::via::QuotedPrint.
+.IP \(bu 4
+\&\f(CW\*(C`NEXT\*(C'\fR, by Damian Conway, is a pseudo-class for method redispatch.
+See NEXT.
+.IP \(bu 4
+\&\f(CW\*(C`open\*(C'\fR is a new pragma for setting the default I/O layers
+for \fBopen()\fR.
+.IP \(bu 4
+\&\f(CW\*(C`PerlIO::scalar\*(C'\fR, by Nick Ing-Simmons, provides the implementation
+of IO to "in memory" Perl scalars as discussed above.  It also serves
+as an example of a loadable PerlIO layer.  Other future possibilities
+include PerlIO::Array and PerlIO::Code.  See PerlIO::scalar.
+.IP \(bu 4
+\&\f(CW\*(C`PerlIO::via\*(C'\fR, by Nick Ing-Simmons, acts as a PerlIO layer and wraps
+PerlIO layer functionality provided by a class (typically implemented
+in Perl code).
+.IP \(bu 4
+\&\f(CW\*(C`PerlIO::via::QuotedPrint\*(C'\fR, by Elizabeth Mattijsen, is an example
+of a \f(CW\*(C`PerlIO::via\*(C'\fR class:
+.Sp
+.Vb 2
+\&    use PerlIO::via::QuotedPrint;
+\&    open($fh,">:via(QuotedPrint)",$path);
+.Ve
+.Sp
+This will automatically convert everything output to \f(CW$fh\fR to
+Quoted-Printable.  See PerlIO::via and PerlIO::via::QuotedPrint.
+.IP \(bu 4
+\&\f(CW\*(C`Pod::ParseLink\*(C'\fR, by Russ Allbery, has been added,
+to parse L<> links in pods as described in the new
+perlpodspec.
+.IP \(bu 4
+\&\f(CW\*(C`Pod::Text::Overstrike\*(C'\fR, by Joe Smith, has been added.
+It converts POD data to formatted overstrike text.
+See Pod::Text::Overstrike. [561+]
+.IP \(bu 4
+\&\f(CW\*(C`Scalar::Util\*(C'\fR is a selection of general-utility scalar subroutines,
+such as \fBblessed()\fR, \fBreftype()\fR, and \fBtainted()\fR.  See Scalar::Util.
+.IP \(bu 4
+\&\f(CW\*(C`sort\*(C'\fR is a new pragma for controlling the behaviour of \fBsort()\fR.
+.IP \(bu 4
+\&\f(CW\*(C`Storable\*(C'\fR gives persistence to Perl data structures by allowing the
+storage and retrieval of Perl data to and from files in a fast and
+compact binary format.  Because in effect Storable does serialisation
+of Perl data structures, with it you can also clone deep, hierarchical
+datastructures.  Storable was originally created by Raphael Manfredi,
+but it is now maintained by Abhijit Menon-Sen.  Storable has been
+enhanced to understand the two new hash features, Unicode keys and
+restricted hashes.  See Storable.
+.IP \(bu 4
+\&\f(CW\*(C`Switch\*(C'\fR, by Damian Conway, has been added.  Just by saying
+.Sp
+.Vb 1
+\&    use Switch;
+.Ve
+.Sp
+you have \f(CW\*(C`switch\*(C'\fR and \f(CW\*(C`case\*(C'\fR available in Perl.
+.Sp
+.Vb 1
+\&    use Switch;
+\&
+\&    switch ($val) {
+\&
+\&                case 1          { print "number 1" }
+\&                case "a"        { print "string a" }
+\&                case [1..10,42] { print "number in list" }
+\&                case (@array)   { print "number in list" }
+\&                case /\ew+/      { print "pattern" }
+\&                case qr/\ew+/    { print "pattern" }
+\&                case (%hash)    { print "entry in hash" }
+\&                case (\e%hash)   { print "entry in hash" }
+\&                case (\e&sub)    { print "arg to subroutine" }
+\&                else            { print "previous case not true" }
+\&    }
+.Ve
+.Sp
+See Switch.
+.IP \(bu 4
+\&\f(CW\*(C`Test::More\*(C'\fR, by Michael Schwern, is yet another framework for writing
+test scripts, more extensive than Test::Simple.  See Test::More.
+.IP \(bu 4
+\&\f(CW\*(C`Test::Simple\*(C'\fR, by Michael Schwern, has basic utilities for writing
+tests.   See Test::Simple.
+.IP \(bu 4
+\&\f(CW\*(C`Text::Balanced\*(C'\fR, by Damian Conway, has been added, for extracting
+delimited text sequences from strings.
+.Sp
+.Vb 1
+\&    use Text::Balanced \*(Aqextract_delimited\*(Aq;
+\&
+\&    ($a, $b) = extract_delimited("\*(Aqnever say never\*(Aq, he never said", "\*(Aq", \*(Aq\*(Aq);
+.Ve
+.Sp
+\&\f(CW$a\fR will be "'never say never'", \f(CW$b\fR will be ', he never said'.
+.Sp
+In addition to \fBextract_delimited()\fR, there are also \fBextract_bracketed()\fR,
+\&\fBextract_quotelike()\fR, \fBextract_codeblock()\fR, \fBextract_variable()\fR,
+\&\fBextract_tagged()\fR, \fBextract_multiple()\fR, \fBgen_delimited_pat()\fR, and
+\&\fBgen_extract_tagged()\fR.  With these, you can implement rather advanced
+parsing algorithms.  See Text::Balanced.
+.IP \(bu 4
+\&\f(CW\*(C`threads\*(C'\fR, by Arthur Bergman, is an interface to interpreter threads.
+Interpreter threads (ithreads) is the new thread model introduced in
+Perl 5.6 but only available as an internal interface for extension
+writers (and for Win32 Perl for \f(CWfork()\fR emulation).  See threads,
+threads::shared, and perlthrtut.
+.IP \(bu 4
+\&\f(CW\*(C`threads::shared\*(C'\fR, by Arthur Bergman, allows data sharing for
+interpreter threads.  See threads::shared.
+.IP \(bu 4
+\&\f(CW\*(C`Tie::File\*(C'\fR, by Mark-Jason Dominus, associates a Perl array with the
+lines of a file.  See Tie::File.
+.IP \(bu 4
+\&\f(CW\*(C`Tie::Memoize\*(C'\fR, by Ilya Zakharevich, provides on-demand loaded hashes.
+See Tie::Memoize.
+.IP \(bu 4
+\&\f(CW\*(C`Tie::RefHash::Nestable\*(C'\fR, by Edward Avis, allows storing hash
+references (unlike the standard Tie::RefHash)  The module is contained
+within Tie::RefHash.  See Tie::RefHash.
+.IP \(bu 4
+\&\f(CW\*(C`Time::HiRes\*(C'\fR, by Douglas E. Wegscheid, provides high resolution
+timing (ualarm, usleep, and gettimeofday).  See Time::HiRes.
+.IP \(bu 4
+\&\f(CW\*(C`Unicode::UCD\*(C'\fR offers a querying interface to the Unicode Character
+Database.  See Unicode::UCD.
+.IP \(bu 4
+\&\f(CW\*(C`Unicode::Collate\*(C'\fR, by SADAHIRO Tomoyuki, implements the UCA
+(Unicode Collation Algorithm) for sorting Unicode strings.
+See Unicode::Collate.
+.IP \(bu 4
+\&\f(CW\*(C`Unicode::Normalize\*(C'\fR, by SADAHIRO Tomoyuki, implements the various
+Unicode normalization forms.  See Unicode::Normalize.
+.IP \(bu 4
+\&\f(CW\*(C`XS::APItest\*(C'\fR, by Tim Jenness, is a test extension that exercises XS
+APIs.  Currently only \f(CWprintf()\fR is tested: how to output various
+basic data types from XS.
+.IP \(bu 4
+\&\f(CW\*(C`XS::Typemap\*(C'\fR, by Tim Jenness, is a test extension that exercises
+XS typemaps.  Nothing gets installed, but the code is worth studying
+for extension writers.
+.SS "Updated And Improved Modules and Pragmata"
+.IX Subsection "Updated And Improved Modules and Pragmata"
+.IP \(bu 4
+The following independently supported modules have been updated to the
+newest versions from CPAN: CGI, CPAN, DB_File, File::Spec, File::Temp,
+Getopt::Long, Math::BigFloat, Math::BigInt, the podlators bundle
+(Pod::Man, Pod::Text), Pod::LaTeX [561+], Pod::Parser, Storable,
+Term::ANSIColor, Test, Text\-Tabs+Wrap.
+.IP \(bu 4
+\&\fBattributes::reftype()\fR now works on tied arguments.
+.IP \(bu 4
+AutoLoader can now be disabled with \f(CW\*(C`no AutoLoader;\*(C'\fR.
+.IP \(bu 4
+B::Deparse has been significantly enhanced by Robin Houston.  It can
+now deparse almost all of the standard test suite (so that the tests
+still succeed).  There is a make target "test.deparse" for trying this
+out.
+.IP \(bu 4
+Carp now has better interface documentation, and the \f(CW@CARP_NOT\fR
+interface has been added to get optional control over where errors
+are reported independently of \f(CW@ISA\fR, by Ben Tilly.
+.IP \(bu 4
+Class::Struct can now define the classes in compile time.
+.IP \(bu 4
+Class::Struct now assigns the array/hash element if the accessor
+is called with an array/hash element as the \fBsole\fR argument.
+.IP \(bu 4
+The return value of \fBCwd::fastcwd()\fR is now tainted.
+.IP \(bu 4
+Data::Dumper now has an option to sort hashes.
+.IP \(bu 4
+Data::Dumper now has an option to dump code references
+using B::Deparse.
+.IP \(bu 4
+DB_File now supports newer Berkeley DB versions, among
+other improvements.
+.IP \(bu 4
+Devel::Peek now has an interface for the Perl memory statistics
+(this works only if you are using perl's malloc, and if you have
+compiled with debugging).
+.IP \(bu 4
+The English module can now be used without the infamous performance
+hit by saying
+.Sp
+.Vb 1
+\&        use English \*(Aq\-no_match_vars\*(Aq;
+.Ve
+.Sp
+(Assuming, of course, that you don't need the troublesome variables
+\&\f(CW\*(C`$\`\*(C'\fR, \f(CW$&\fR, or \f(CW\*(C`$\*(Aq\*(C'\fR.)  Also, introduced \f(CW@LAST_MATCH_START\fR and
+\&\f(CW@LAST_MATCH_END\fR English aliases for \f(CW\*(C`@\-\*(C'\fR and \f(CW\*(C`@+\*(C'\fR.
+.IP \(bu 4
+ExtUtils::MakeMaker has been significantly cleaned up and fixed.
+The enhanced version has also been backported to earlier releases
+of Perl and submitted to CPAN so that the earlier releases can
+enjoy the fixes.
+.IP \(bu 4
+The arguments of \fBWriteMakefile()\fR in Makefile.PL are now checked
+for sanity much more carefully than before.  This may cause new
+warnings when modules are being installed.  See ExtUtils::MakeMaker
+for more details.
+.IP \(bu 4
+ExtUtils::MakeMaker now uses File::Spec internally, which hopefully
+leads to better portability.
+.IP \(bu 4
+Fcntl, Socket, and Sys::Syslog have been rewritten by Nicholas Clark
+to use the new-style constant dispatch section (see ExtUtils::Constant).
+This means that they will be more robust and hopefully faster.
+.IP \(bu 4
+File::Find now \fBchdir()\fRs correctly when chasing symbolic links. [561]
+.IP \(bu 4
+File::Find now has pre\- and post-processing callbacks.  It also
+correctly changes directories when chasing symbolic links.  Callbacks
+(naughtily) exiting with "next;" instead of "return;" now work.
+.IP \(bu 4
+File::Find is now (again) reentrant.  It also has been made
+more portable.
+.IP \(bu 4
+The warnings issued by File::Find now belong to their own category.
+You can enable/disable them with \f(CW\*(C`use/no warnings \*(AqFile::Find\*(Aq;\*(C'\fR.
+.IP \(bu 4
+\&\fBFile::Glob::glob()\fR has been renamed to \fBFile::Glob::bsd_glob()\fR
+because the name clashes with the builtin \fBglob()\fR.  The older
+name is still available for compatibility, but is deprecated. [561]
+.IP \(bu 4
+File::Glob now supports \f(CW\*(C`GLOB_LIMIT\*(C'\fR constant to limit the size of
+the returned list of filenames.
+.IP \(bu 4
+IPC::Open3 now allows the use of numeric file descriptors.
+.IP \(bu 4
+IO::Socket now has an \fBatmark()\fR method, which returns true if the socket
+is positioned at the out-of-band mark.  The method is also exportable
+as a \fBsockatmark()\fR function.
+.IP \(bu 4
+IO::Socket::INET failed to open the specified port if the service name
+was not known.  It now correctly uses the supplied port number as is. [561]
+.IP \(bu 4
+IO::Socket::INET has support for the ReusePort option (if your
+platform supports it).  The Reuse option now has an alias, ReuseAddr.
+For clarity, you may want to prefer ReuseAddr.
+.IP \(bu 4
+IO::Socket::INET now supports a value of zero for \f(CW\*(C`LocalPort\*(C'\fR
+(usually meaning that the operating system will make one up.)
+.IP \(bu 4
+\&'use lib' now works identically to \f(CW@INC\fR.  Removing directories
+with 'no lib' now works.
+.IP \(bu 4
+Math::BigFloat and Math::BigInt have undergone a full rewrite by Tels.
+They are now magnitudes faster, and they support various bignum
+libraries such as GMP and PARI as their backends.
+.IP \(bu 4
+Math::Complex handles inf, NaN etc., better.
+.IP \(bu 4
+Net::Ping has been considerably enhanced by Rob Brown: multihoming is
+now supported, Win32 functionality is better, there is now time
+measuring functionality (optionally high-resolution using
+Time::HiRes), and there is now "external" protocol which uses
+Net::Ping::External module which runs your external ping utility and
+parses the output.  A version of Net::Ping::External is available in
+CPAN.
+.Sp
+Note that some of the Net::Ping tests are disabled when running
+under the Perl distribution since one cannot assume one or more
+of the following: enabled echo port at localhost, full Internet
+connectivity, or sympathetic firewalls.  You can set the environment
+variable PERL_TEST_Net_Ping to "1" (one) before running the Perl test
+suite to enable all the Net::Ping tests.
+.IP \(bu 4
+\&\fBPOSIX::sigaction()\fR is now much more flexible and robust.
+You can now install coderef handlers, 'DEFAULT', and 'IGNORE'
+handlers, installing new handlers was not atomic.
+.IP \(bu 4
+In Safe, \f(CW%INC\fR is now localised in a Safe compartment so that
+use/require work.
+.IP \(bu 4
+In SDBM_File on DOSish platforms, some keys went missing because of
+lack of support for files with "holes".  A workaround for the problem
+has been added.
+.IP \(bu 4
+In Search::Dict one can now have a pre-processing hook for the
+lines being searched.
+.IP \(bu 4
+The Shell module now has an OO interface.
+.IP \(bu 4
+In Sys::Syslog there is now a failover mechanism that will go
+through alternative connection mechanisms until the message
+is successfully logged.
+.IP \(bu 4
+The Test module has been significantly enhanced.
+.IP \(bu 4
+\&\fBTime::Local::timelocal()\fR does not handle fractional seconds anymore.
+The rationale is that neither does \fBlocaltime()\fR, and \fBtimelocal()\fR and
+\&\fBlocaltime()\fR are supposed to be inverses of each other.
+.IP \(bu 4
+The vars pragma now supports declaring fully qualified variables.
+(Something that \f(CWour()\fR does not and will not support.)
+.IP \(bu 4
+The \f(CW\*(C`utf8::\*(C'\fR name space (as in the pragma) provides various
+Perl-callable functions to provide low level access to Perl's
+internal Unicode representation.  At the moment only \fBlength()\fR
+has been implemented.
+.SH "Utility Changes"
+.IX Header "Utility Changes"
+.IP \(bu 4
+Emacs perl mode (emacs/cperl\-mode.el) has been updated to version
+4.31.
+.IP \(bu 4
+\&\fIemacs/e2ctags.pl\fR is now much faster.
+.IP \(bu 4
+\&\f(CW\*(C`enc2xs\*(C'\fR is a tool for people adding their own encodings to the
+Encode module.
+.IP \(bu 4
+\&\f(CW\*(C`h2ph\*(C'\fR now supports C trigraphs.
+.IP \(bu 4
+\&\f(CW\*(C`h2xs\*(C'\fR now produces a template README.
+.IP \(bu 4
+\&\f(CW\*(C`h2xs\*(C'\fR now uses \f(CW\*(C`Devel::PPPort\*(C'\fR for better portability between
+different versions of Perl.
+.IP \(bu 4
+\&\f(CW\*(C`h2xs\*(C'\fR uses the new ExtUtils::Constant module
+which will affect newly created extensions that define constants.
+Since the new code is more correct (if you have two constants where the
+first one is a prefix of the second one, the first constant \fBnever\fR
+got defined), less lossy (it uses integers for integer constant,
+as opposed to the old code that used floating point numbers even for
+integer constants), and slightly faster, you might want to consider
+regenerating your extension code (the new scheme makes regenerating
+easy).  h2xs now also supports C trigraphs.
+.IP \(bu 4
+\&\f(CW\*(C`libnetcfg\*(C'\fR has been added to configure libnet.
+.IP \(bu 4
+\&\f(CW\*(C`perlbug\*(C'\fR is now much more robust.  It also sends the bug report to
+perl.org, not perl.com.
+.IP \(bu 4
+\&\f(CW\*(C`perlcc\*(C'\fR has been rewritten and its user interface (that is,
+command line) is much more like that of the Unix C compiler, cc.
+(The perlbc tools has been removed.  Use \f(CW\*(C`perlcc \-B\*(C'\fR instead.)
+\&\fBNote that perlcc is still considered very experimental and
+unsupported.\fR [561]
+.IP \(bu 4
+\&\f(CW\*(C`perlivp\*(C'\fR is a new Installation Verification Procedure utility
+for running any time after installing Perl.
+.IP \(bu 4
+\&\f(CW\*(C`piconv\*(C'\fR is an implementation of the character conversion utility
+\&\f(CW\*(C`iconv\*(C'\fR, demonstrating the new Encode module.
+.IP \(bu 4
+\&\f(CW\*(C`pod2html\*(C'\fR now allows specifying a cache directory.
+.IP \(bu 4
+\&\f(CW\*(C`pod2html\*(C'\fR now produces XHTML 1.0.
+.IP \(bu 4
+\&\f(CW\*(C`pod2html\*(C'\fR now understands POD written using different line endings
+(PC-like CRLF versus Unix-like LF versus MacClassic-like CR).
+.IP \(bu 4
+\&\f(CW\*(C`s2p\*(C'\fR has been completely rewritten in Perl.  (It is in fact a full
+implementation of sed in Perl: you can use the sed functionality by
+using the \f(CW\*(C`psed\*(C'\fR utility.)
+.IP \(bu 4
+\&\f(CW\*(C`xsubpp\*(C'\fR now understands POD documentation embedded in the *.xs
+files. [561]
+.IP \(bu 4
+\&\f(CW\*(C`xsubpp\*(C'\fR now supports the OUT keyword.
+.SH "New Documentation"
+.IX Header "New Documentation"
+.IP \(bu 4
+perl56delta details the changes between the 5.005 release and the
+5.6.0 release.
+.IP \(bu 4
+perlclib documents the internal replacements for standard C library
+functions.  (Interesting only for extension writers and Perl core
+hackers.) [561+]
+.IP \(bu 4
+perldebtut is a Perl debugging tutorial. [561+]
+.IP \(bu 4
+perlebcdic contains considerations for running Perl on EBCDIC
+platforms. [561+]
+.IP \(bu 4
+perlintro is a gentle introduction to Perl.
+.IP \(bu 4
+perliol documents the internals of PerlIO with layers.
+.IP \(bu 4
+perlmodstyle is a style guide for writing modules.
+.IP \(bu 4
+perlnewmod tells about writing and submitting a new module. [561+]
+.IP \(bu 4
+perlpacktut is a \fBpack()\fR tutorial.
+.IP \(bu 4
+perlpod has been rewritten to be clearer and to record the best
+practices gathered over the years.
+.IP \(bu 4
+perlpodspec is a more formal specification of the pod format,
+mainly of interest for writers of pod applications, not to
+people writing in pod.
+.IP \(bu 4
+perlretut is a regular expression tutorial. [561+]
+.IP \(bu 4
+perlrequick is a regular expressions quick-start guide.
+Yes, much quicker than perlretut. [561]
+.IP \(bu 4
+perltodo has been updated.
+.IP \(bu 4
+perltootc has been renamed as perltooc (to not to conflict
+with perltoot in filesystems restricted to "8.3" names).
+.IP \(bu 4
+perluniintro is an introduction to using Unicode in Perl.
+(perlunicode is more of a detailed reference and background
+information)
+.IP \(bu 4
+perlutil explains the command line utilities packaged with the Perl
+distribution. [561+]
+.PP
+The following platform-specific documents are available before
+the installation as README.\fIplatform\fR, and after the installation
+as perl\fIplatform\fR:
+.PP
+.Vb 5
+\&    perlaix perlamiga perlapollo perlbeos perlbs2000
+\&    perlce perlcygwin perldgux perldos perlepoc perlfreebsd perlhpux
+\&    perlhurd perlirix perlmachten perlmacos perlmint perlmpeix
+\&    perlnetware perlos2 perlos390 perlplan9 perlqnx perlsolaris
+\&    perltru64 perluts perlvmesa perlvms perlvos perlwin32
+.Ve
+.PP
+These documents usually detail one or more of the following subjects:
+configuring, building, testing, installing, and sometimes also using
+Perl on the said platform.
+.PP
+Eastern Asian Perl users are now welcomed in their own languages:
+README.jp (Japanese), README.ko (Korean), README.cn (simplified
+Chinese) and README.tw (traditional Chinese), which are written in
+normal pod but encoded in EUC-JP, EUC-KR, EUC-CN and Big5.  These
+will get installed as
+.PP
+.Vb 1
+\&   perljp perlko perlcn perltw
+.Ve
+.IP \(bu 4
+The documentation for the POSIX-BC platform is called "BS2000", to avoid
+confusion with the Perl POSIX module.
+.IP \(bu 4
+The documentation for the WinCE platform is called perlce (README.ce
+in the source code kit), to avoid confusion with the perlwin32
+documentation on 8.3\-restricted filesystems.
+.SH "Performance Enhancements"
+.IX Header "Performance Enhancements"
+.IP \(bu 4
+\&\fBmap()\fR could get pathologically slow when the result list it generates
+is larger than the source list.  The performance has been improved for
+common scenarios. [561]
+.IP \(bu 4
+\&\fBsort()\fR is also fully reentrant, in the sense that the sort function
+can itself call \fBsort()\fR.  This did not work reliably in previous
+releases. [561]
+.IP \(bu 4
+\&\fBsort()\fR has been changed to use primarily mergesort internally as
+opposed to the earlier quicksort.  For very small lists this may
+result in slightly slower sorting times, but in general the speedup
+should be at least 20%.  Additional bonuses are that the worst case
+behaviour of \fBsort()\fR is now better (in computer science terms it now
+runs in time O(N log N), as opposed to quicksort's Theta(N**2)
+worst-case run time behaviour), and that \fBsort()\fR is now stable
+(meaning that elements with identical keys will stay ordered as they
+were before the sort).  See the \f(CW\*(C`sort\*(C'\fR pragma for information.
+.Sp
+The story in more detail: suppose you want to serve yourself a little
+slice of Pi.
+.Sp
+.Vb 1
+\&    @digits = ( 3,1,4,1,5,9 );
+.Ve
+.Sp
+A numerical sort of the digits will yield (1,1,3,4,5,9), as expected.
+Which \f(CW1\fR comes first is hard to know, since one \f(CW1\fR looks pretty
+much like any other.  You can regard this as totally trivial,
+or somewhat profound.  However, if you just want to sort the even
+digits ahead of the odd ones, then what will
+.Sp
+.Vb 1
+\&    sort { ($a % 2) <=> ($b % 2) } @digits;
+.Ve
+.Sp
+yield?  The only even digit, \f(CW4\fR, will come first.  But how about
+the odd numbers, which all compare equal?  With the quicksort algorithm
+used to implement Perl 5.6 and earlier, the order of ties is left up
+to the sort.  So, as you add more and more digits of Pi, the order
+in which the sorted even and odd digits appear will change.
+and, for sufficiently large slices of Pi, the quicksort algorithm
+in Perl 5.8 won't return the same results even if reinvoked with the
+same input.  The justification for this rests with quicksort's
+worst case behavior.  If you run
+.Sp
+.Vb 1
+\&   sort { $a <=> $b } ( 1 .. $N , 1 .. $N );
+.Ve
+.Sp
+(something you might approximate if you wanted to merge two sorted
+arrays using sort), doubling \f(CW$N\fR doesn't just double the quicksort time,
+it \fIquadruples\fR it.  Quicksort has a worst case run time that can
+grow like N**2, so-called \fIquadratic\fR behaviour, and it can happen
+on patterns that may well arise in normal use.  You won't notice this
+for small arrays, but you \fIwill\fR notice it with larger arrays,
+and you may not live long enough for the sort to complete on arrays
+of a million elements.  So the 5.8 quicksort scrambles large arrays
+before sorting them, as a statistical defence against quadratic behaviour.
+But that means if you sort the same large array twice, ties may be
+broken in different ways.
+.Sp
+Because of the unpredictability of tie-breaking order, and the quadratic
+worst-case behaviour, quicksort was \fIalmost\fR replaced completely with
+a stable mergesort.  \fIStable\fR means that ties are broken to preserve
+the original order of appearance in the input array.  So
+.Sp
+.Vb 1
+\&    sort { ($a % 2) <=> ($b % 2) } (3,1,4,1,5,9);
+.Ve
+.Sp
+will yield (4,3,1,1,5,9), guaranteed.  The even and odd numbers
+appear in the output in the same order they appeared in the input.
+Mergesort has worst case O(N log N) behaviour, the best value
+attainable.  And, ironically, this mergesort does particularly
+well where quicksort goes quadratic:  mergesort sorts (1..$N, 1..$N)
+in O(N) time.  But quicksort was rescued at the last moment because
+it is faster than mergesort on certain inputs and platforms.
+For example, if you really \fIdon't\fR care about the order of even
+and odd digits, quicksort will run in O(N) time; it's very good
+at sorting many repetitions of a small number of distinct elements.
+The quicksort divide and conquer strategy works well on platforms
+with relatively small, very fast, caches.  Eventually, the problem gets
+whittled down to one that fits in the cache, from which point it
+benefits from the increased memory speed.
+.Sp
+Quicksort was rescued by implementing a sort pragma to control aspects
+of the sort.  The \fBstable\fR subpragma forces stable behaviour,
+regardless of algorithm.  The \fB_quicksort\fR and \fB_mergesort\fR
+subpragmas are heavy-handed ways to select the underlying implementation.
+The leading \f(CW\*(C`_\*(C'\fR is a reminder that these subpragmas may not survive
+beyond 5.8.  More appropriate mechanisms for selecting the implementation
+exist, but they wouldn't have arrived in time to save quicksort.
+.IP \(bu 4
+Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
+( http://burtleburtle.net/bob/hash/doobs.html ).  This algorithm is
+reasonably fast while producing a much better spread of values than
+the old hashing algorithm (originally by Chris Torek, later tweaked by
+Ilya Zakharevich).  Hash values output from the algorithm on a hash of
+all 3\-char printable ASCII keys comes much closer to passing the
+DIEHARD random number generation tests.  According to perlbench, this
+change has not affected the overall speed of Perl.
+.IP \(bu 4
+\&\fBunshift()\fR should now be noticeably faster.
+.SH "Installation and Configuration Improvements"
+.IX Header "Installation and Configuration Improvements"
+.SS "Generic Improvements"
+.IX Subsection "Generic Improvements"
+.IP \(bu 4
+INSTALL now explains how you can configure Perl to use 64\-bit
+integers even on non\-64\-bit platforms.
+.IP \(bu 4
+Policy.sh policy change: if you are reusing a Policy.sh file
+(see INSTALL) and you use Configure \-Dprefix=/foo/bar and in the old
+Policy \f(CW$prefix\fR eq \f(CW$siteprefix\fR and \f(CW$prefix\fR eq \f(CW$vendorprefix\fR, all of
+them will now be changed to the new prefix, /foo/bar.  (Previously
+only \f(CW$prefix\fR changed.)  If you do not like this new behaviour,
+specify prefix, siteprefix, and vendorprefix explicitly.
+.IP \(bu 4
+A new optional location for Perl libraries, otherlibdirs, is available.
+It can be used for example for vendor add-ons without disturbing Perl's
+own library directories.
+.IP \(bu 4
+In many platforms, the vendor-supplied 'cc' is too stripped-down to
+build Perl (basically, 'cc' doesn't do ANSI C).  If this seems
+to be the case and 'cc' does not seem to be the GNU C compiler
+\&'gcc', an automatic attempt is made to find and use 'gcc' instead.
+.IP \(bu 4
+gcc needs to closely track the operating system release to avoid
+build problems. If Configure finds that gcc was built for a different
+operating system release than is running, it now gives a clearly visible
+warning that there may be trouble ahead.
+.IP \(bu 4
+Since Perl 5.8 is not binary-compatible with previous releases
+of Perl, Configure no longer suggests including the 5.005
+modules in \f(CW@INC\fR.
+.IP \(bu 4
+Configure \f(CW\*(C`\-S\*(C'\fR can now run non-interactively. [561]
+.IP \(bu 4
+Configure support for pdp11\-style memory models has been removed due
+to obsolescence. [561]
+.IP \(bu 4
+configure.gnu now works with options with whitespace in them.
+.IP \(bu 4
+installperl now outputs everything to STDERR.
+.IP \(bu 4
+Because PerlIO is now the default on most platforms, "\-perlio" doesn't
+get appended to the \f(CW$Config\fR{archname} (also known as $^O) anymore.
+Instead, if you explicitly choose not to use perlio (Configure command
+line option \-Uuseperlio), you will get "\-stdio" appended.
+.IP \(bu 4
+Another change related to the architecture name is that "\-64all"
+(\-Duse64bitall, or "maximally 64\-bit") is appended only if your
+pointers are 64 bits wide.  (To be exact, the use64bitall is ignored.)
+.IP \(bu 4
+In AFS installations, one can configure the root of the AFS to be
+somewhere else than the default \fI/afs\fR by using the Configure
+parameter \f(CW\*(C`\-Dafsroot=/some/where/else\*(C'\fR.
+.IP \(bu 4
+APPLLIB_EXP, a lesser-known configuration-time definition, has been
+documented.  It can be used to prepend site-specific directories
+to Perl's default search path (@INC); see INSTALL for information.
+.IP \(bu 4
+The version of Berkeley DB used when the Perl (and, presumably, the
+DB_File extension) was built is now available as
+\&\f(CW@Config{qw(db_version_major db_version_minor db_version_patch)}\fR
+from Perl and as \f(CW\*(C`DB_VERSION_MAJOR_CFG DB_VERSION_MINOR_CFG
+DB_VERSION_PATCH_CFG\*(C'\fR from C.
+.IP \(bu 4
+Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM
+has been documented in INSTALL.
+.IP \(bu 4
+If you have CPAN access (either network or a local copy such as a
+CD-ROM) you can during specify extra modules to Configure to build and
+install with Perl using the \-Dextras=...  option.  See INSTALL for
+more details.
+.IP \(bu 4
+In addition to config.over, a new override file, config.arch, is
+available.  This file is supposed to be used by hints file writers
+for architecture-wide changes (as opposed to config.over which is
+for site-wide changes).
+.IP \(bu 4
+If your file system supports symbolic links, you can build Perl outside
+of the source directory by
+.Sp
+.Vb 3
+\&        mkdir perl/build/directory
+\&        cd perl/build/directory
+\&        sh /path/to/perl/source/Configure \-Dmksymlinks ...
+.Ve
+.Sp
+This will create in perl/build/directory a tree of symbolic links
+pointing to files in /path/to/perl/source.  The original files are left
+unaffected.  After Configure has finished, you can just say
+.Sp
+.Vb 1
+\&        make all test
+.Ve
+.Sp
+and Perl will be built and tested, all in perl/build/directory.
+[561]
+.IP \(bu 4
+For Perl developers, several new make targets for profiling
+and debugging have been added; see perlhack.
+.RS 4
+.IP \(bu 8
+Use of the \fIgprof\fR tool to profile Perl has been documented in
+perlhack.  There is a make target called "perl.gprof" for
+generating a gprofiled Perl executable.
+.IP \(bu 8
+If you have GCC 3, there is a make target called "perl.gcov" for
+creating a gcoved Perl executable for coverage analysis.  See
+perlhack.
+.IP \(bu 8
+If you are on IRIX or Tru64 platforms, new profiling/debugging options
+have been added; see perlhack for more information about pixie and
+Third Degree.
+.RE
+.RS 4
+.RE
+.IP \(bu 4
+Guidelines of how to construct minimal Perl installations have
+been added to INSTALL.
+.IP \(bu 4
+The Thread extension is now not built at all under ithreads
+(\f(CW\*(C`Configure \-Duseithreads\*(C'\fR) because it wouldn't work anyway (the
+Thread extension requires being Configured with \f(CW\*(C`\-Duse5005threads\*(C'\fR).
+.Sp
+\&\fBNote that the 5.005 threads are unsupported and deprecated: if you
+have code written for the old threads you should migrate it to the
+new ithreads model.\fR
+.IP \(bu 4
+The Gconvert macro ($Config{d_Gconvert}) used by perl for stringifying
+floating-point numbers is now more picky about using sprintf %.*g
+rules for the conversion.  Some platforms that used to use gcvt may
+now resort to the slower sprintf.
+.IP \(bu 4
+The obsolete method of making a special (e.g., debugging) flavor
+of perl by saying
+.Sp
+.Vb 1
+\&        make LIBPERL=libperld.a
+.Ve
+.Sp
+has been removed. Use \-DDEBUGGING instead.
+.SS "New Or Improved Platforms"
+.IX Subsection "New Or Improved Platforms"
+For the list of platforms known to support Perl,
+see "Supported Platforms" in perlport.
+.IP \(bu 4
+AIX dynamic loading should be now better supported.
+.IP \(bu 4
+AIX should now work better with gcc, threads, and 64\-bitness.  Also the
+long doubles support in AIX should be better now.  See perlaix.
+.IP \(bu 4
+AtheOS ( http://www.atheos.cx/ ) is a new platform.
+.IP \(bu 4
+BeOS has been reclaimed.
+.IP \(bu 4
+The DG/UX platform now supports 5.005\-style threads.
+See perldgux.
+.IP \(bu 4
+The DYNIX/ptx platform (also known as dynixptx) is supported at or
+near osvers 4.5.2.
+.IP \(bu 4
+EBCDIC platforms (z/OS (also known as OS/390), POSIX-BC, and VM/ESA)
+have been regained.  Many test suite tests still fail and the
+co-existence of Unicode and EBCDIC isn't quite settled, but the
+situation is much better than with Perl 5.6.  See perlos390,
+perlbs2000 (for POSIX-BC), and perlvmesa for more information.
+(\fBNote:\fR support for VM/ESA was removed in Perl v5.18.0. The relevant
+information was in \fIREADME.vmesa\fR)
+.IP \(bu 4
+Building perl with \-Duseithreads or \-Duse5005threads now works under
+HP-UX 10.20 (previously it only worked under 10.30 or later). You will
+need a thread library package installed. See README.hpux. [561]
+.IP \(bu 4
+Mac OS Classic is now supported in the mainstream source package
+(MacPerl has of course been available since perl 5.004 but now the
+source code bases of standard Perl and MacPerl have been synchronised)
+[561]
+.IP \(bu 4
+Mac OS X (or Darwin) should now be able to build Perl even on HFS+
+filesystems.  (The case-insensitivity used to confuse the Perl build
+process.)
+.IP \(bu 4
+NCR MP-RAS is now supported. [561]
+.IP \(bu 4
+All the NetBSD specific patches (except for the installation
+specific ones) have been merged back to the main distribution.
+.IP \(bu 4
+NetWare from Novell is now supported.  See perlnetware.
+.IP \(bu 4
+NonStop-UX is now supported. [561]
+.IP \(bu 4
+NEC SUPER-UX is now supported.
+.IP \(bu 4
+All the OpenBSD specific patches (except for the installation
+specific ones) have been merged back to the main distribution.
+.IP \(bu 4
+Perl has been tested with the GNU pth userlevel thread package
+( http://www.gnu.org/software/pth/pth.html ).  All thread tests
+of Perl now work, but not without adding some \fByield()\fRs to the tests,
+so while pth (and other userlevel thread implementations) can be
+considered to be "working" with Perl ithreads, keep in mind the
+possible non-preemptability of the underlying thread implementation.
+.IP \(bu 4
+Stratus VOS is now supported using Perl's native build method
+(Configure).  This is the recommended method to build Perl on
+VOS.  The older methods, which build miniperl, are still
+available.  See perlvos. [561+]
+.IP \(bu 4
+The Amdahl UTS Unix mainframe platform is now supported. [561]
+.IP \(bu 4
+WinCE is now supported.  See perlce.
+.IP \(bu 4
+z/OS (formerly known as OS/390, formerly known as MVS OE) now has
+support for dynamic loading.  This is not selected by default,
+however, you must specify \-Dusedl in the arguments of Configure. [561]
+.SH "Selected Bug Fixes"
+.IX Header "Selected Bug Fixes"
+Numerous memory leaks and uninitialized memory accesses have been
+hunted down.  Most importantly, anonymous subs used to leak quite
+a bit. [561]
+.IP \(bu 4
+The autouse pragma didn't work for Multi::Part::Function::Names.
+.IP \(bu 4
+\&\fBcaller()\fR could cause core dumps in certain situations.  Carp was
+sometimes affected by this problem.  In particular, \fBcaller()\fR now
+returns a subroutine name of \f(CW\*(C`(unknown)\*(C'\fR for subroutines that have
+been removed from the symbol table.
+.IP \(bu 4
+chop(@list) in list context returned the characters chopped in
+reverse order.  This has been reversed to be in the right order. [561]
+.IP \(bu 4
+Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
+when building the Perl binary.  The only exception to this is SunOS 4.x,
+which needs them. [561]
+.IP \(bu 4
+The behaviour of non-decimal but numeric string constants such as
+"0x23" was platform-dependent: in some platforms that was seen as 35,
+in some as 0, in some as a floating point number (don't ask).  This
+was caused by Perl's using the operating system libraries in a situation
+where the result of the string to number conversion is undefined: now
+Perl consistently handles such strings as zero in numeric contexts.
+.IP \(bu 4
+Several debugger fixes: exit code now reflects the script exit code,
+condition \f(CW"0"\fR now treated correctly, the \f(CW\*(C`d\*(C'\fR command now checks
+line number, \f(CW$.\fR no longer gets corrupted, and all debugger output
+now goes correctly to the socket if RemotePort is set. [561]
+.IP \(bu 4
+The debugger (perl5db.pl) has been modified to present a more
+consistent commands interface, via (CommandSet=580).  perl5db.t was
+also added to test the changes, and as a placeholder for further tests.
+.Sp
+See perldebug.
+.IP \(bu 4
+The debugger has a new \f(CW\*(C`dumpDepth\*(C'\fR option to control the maximum
+depth to which nested structures are dumped.  The \f(CW\*(C`x\*(C'\fR command has
+been extended so that \f(CW\*(C`x N EXPR\*(C'\fR dumps out the value of \fIEXPR\fR to a
+depth of at most \fIN\fR levels.
+.IP \(bu 4
+The debugger can now show lexical variables if you have the CPAN
+module PadWalker installed.
+.IP \(bu 4
+The order of DESTROYs has been made more predictable.
+.IP \(bu 4
+Perl 5.6.0 could emit spurious warnings about redefinition of
+\&\fBdl_error()\fR when statically building extensions into perl.
+This has been corrected. [561]
+.IP \(bu 4
+dprofpp \-R didn't work.
+.IP \(bu 4
+\&\f(CW*foo{FORMAT}\fR now works.
+.IP \(bu 4
+Infinity is now recognized as a number.
+.IP \(bu 4
+UNIVERSAL::isa no longer caches methods incorrectly.  (This broke
+the Tk extension with 5.6.0.) [561]
+.IP \(bu 4
+Lexicals I: lexicals outside an eval "" weren't resolved
+correctly inside a subroutine definition inside the eval "" if they
+were not already referenced in the top level of the eval""ed code.
+.IP \(bu 4
+Lexicals II: lexicals leaked at file scope into subroutines that
+were declared before the lexicals.
+.IP \(bu 4
+Lexical warnings now propagating correctly between scopes
+and into \f(CW\*(C`eval "..."\*(C'\fR.
+.IP \(bu 4
+\&\f(CW\*(C`use warnings qw(FATAL all)\*(C'\fR did not work as intended.  This has been
+corrected. [561]
+.IP \(bu 4
+\&\fBwarnings::enabled()\fR now reports the state of $^W correctly if the caller
+isn't using lexical warnings. [561]
+.IP \(bu 4
+Line renumbering with eval and \f(CW\*(C`#line\*(C'\fR now works. [561]
+.IP \(bu 4
+Fixed numerous memory leaks, especially in eval "".
+.IP \(bu 4
+Localised tied variables no longer leak memory
+.Sp
+.Vb 2
+\&    use Tie::Hash;
+\&    tie my %tied_hash => \*(AqTie::StdHash\*(Aq;
+\&
+\&    ...
+\&
+\&    # Used to leak memory every time local() was called;
+\&    # in a loop, this added up.
+\&    local($tied_hash{Foo}) = 1;
+.Ve
+.IP \(bu 4
+Localised hash elements (and \f(CW%ENV\fR) are correctly unlocalised to not
+exist, if they didn't before they were localised.
+.Sp
+.Vb 2
+\&    use Tie::Hash;
+\&    tie my %tied_hash => \*(AqTie::StdHash\*(Aq;
+\&
+\&    ...
+\&
+\&    # Nothing has set the FOO element so far
+\&
+\&    { local $tied_hash{FOO} = \*(AqBar\*(Aq }
+\&
+\&    # This used to print, but not now.
+\&    print "exists!\en" if exists $tied_hash{FOO};
+.Ve
+.Sp
+As a side effect of this fix, tied hash interfaces \fBmust\fR define
+the EXISTS and DELETE methods.
+.IP \(bu 4
+\&\fBmkdir()\fR now ignores trailing slashes in the directory name,
+as mandated by POSIX.
+.IP \(bu 4
+Some versions of glibc have a broken \fBmodfl()\fR.  This affects builds
+with \f(CW\*(C`\-Duselongdouble\*(C'\fR.  This version of Perl detects this brokenness
+and has a workaround for it.  The glibc release 2.2.2 is known to have
+fixed the \fBmodfl()\fR bug.
+.IP \(bu 4
+Modulus of unsigned numbers now works (4063328477 % 65535 used to
+return 27406, instead of 27047). [561]
+.IP \(bu 4
+Some "not a number" warnings introduced in 5.6.0 eliminated to be
+more compatible with 5.005.  Infinity is now recognised as a number. [561]
+.IP \(bu 4
+Numeric conversions did not recognize changes in the string value
+properly in certain circumstances. [561]
+.IP \(bu 4
+Attributes (such as :shared) didn't work with \fBour()\fR.
+.IP \(bu 4
+\&\fBour()\fR variables will not cause bogus "Variable will not stay shared"
+warnings. [561]
+.IP \(bu 4
+"our" variables of the same name declared in two sibling blocks
+resulted in bogus warnings about "redeclaration" of the variables.
+The problem has been corrected. [561]
+.IP \(bu 4
+pack "Z" now correctly terminates the string with "\e0".
+.IP \(bu 4
+Fix password routines which in some shadow password platforms
+(e.g. HP-UX) caused \fBgetpwent()\fR to return every other entry.
+.IP \(bu 4
+The PERL5OPT environment variable (for passing command line arguments
+to Perl) didn't work for more than a single group of options. [561]
+.IP \(bu 4
+PERL5OPT with embedded spaces didn't work.
+.IP \(bu 4
+\&\fBprintf()\fR no longer resets the numeric locale to "C".
+.IP \(bu 4
+\&\f(CWqw(a\e\eb)\fR now parses correctly as \f(CW\*(Aqa\e\eb\*(Aq\fR: that is, as three
+characters, not four. [561]
+.IP \(bu 4
+\&\fBpos()\fR did not return the correct value within s///ge in earlier
+versions.  This is now handled correctly. [561]
+.IP \(bu 4
+Printing quads (64\-bit integers) with printf/sprintf now works
+without the q L ll prefixes (assuming you are on a quad-capable platform).
+.IP \(bu 4
+Regular expressions on references and overloaded scalars now work. [561+]
+.IP \(bu 4
+Right-hand side magic (GMAGIC) could in many cases such as string
+concatenation be invoked too many times.
+.IP \(bu 4
+\&\fBscalar()\fR now forces scalar context even when used in void context.
+.IP \(bu 4
+SOCKS support is now much more robust.
+.IP \(bu 4
+\&\fBsort()\fR arguments are now compiled in the right wantarray context
+(they were accidentally using the context of the \fBsort()\fR itself).
+The comparison block is now run in scalar context, and the arguments
+to be sorted are always provided list context. [561]
+.IP \(bu 4
+Changed the POSIX character class \f(CW\*(C`[[:space:]]\*(C'\fR to include the (very
+rarely used) vertical tab character.  Added a new POSIX-ish character
+class \f(CW\*(C`[[:blank:]]\*(C'\fR which stands for horizontal whitespace
+(currently, the space and the tab).
+.IP \(bu 4
+The tainting behaviour of \fBsprintf()\fR has been rationalized.  It does
+not taint the result of floating point formats anymore, making the
+behaviour consistent with that of string interpolation. [561]
+.IP \(bu 4
+Some cases of inconsistent taint propagation (such as within hash
+values) have been fixed.
+.IP \(bu 4
+The RE engine found in Perl 5.6.0 accidentally pessimised certain kinds
+of simple pattern matches.  These are now handled better. [561]
+.IP \(bu 4
+Regular expression debug output (whether through \f(CW\*(C`use re \*(Aqdebug\*(Aq\*(C'\fR
+or via \f(CW\*(C`\-Dr\*(C'\fR) now looks better. [561]
+.IP \(bu 4
+Multi-line matches like \f(CW\*(C`"a\enxb\en" =~ /(?!\eA)x/m\*(C'\fR were flawed.  The
+bug has been fixed. [561]
+.IP \(bu 4
+Use of $& could trigger a core dump under some situations.  This
+is now avoided. [561]
+.IP \(bu 4
+The regular expression captured submatches ($1, \f(CW$2\fR, ...) are now
+more consistently unset if the match fails, instead of leaving false
+data lying around in them. [561]
+.IP \(bu 4
+\&\fBreadline()\fR on files opened in "slurp" mode could return an extra
+"" (blank line) at the end in certain situations.  This has been
+corrected. [561]
+.IP \(bu 4
+Autovivification of symbolic references of special variables described
+in perlvar (as in \f(CW\*(C`${$num}\*(C'\fR) was accidentally disabled.  This works
+again now. [561]
+.IP \(bu 4
+Sys::Syslog ignored the \f(CW\*(C`LOG_AUTH\*(C'\fR constant.
+.IP \(bu 4
+\&\f(CW$AUTOLOAD\fR, \fBsort()\fR, \fBlock()\fR, and spawning subprocesses
+in multiple threads simultaneously are now thread-safe.
+.IP \(bu 4
+Tie::Array's SPLICE method was broken.
+.IP \(bu 4
+Allow a read-only string on the left-hand side of a non-modifying tr///.
+.IP \(bu 4
+If \f(CW\*(C`STDERR\*(C'\fR is tied, warnings caused by \f(CW\*(C`warn\*(C'\fR and \f(CW\*(C`die\*(C'\fR now
+correctly pass to it.
+.IP \(bu 4
+Several Unicode fixes.
+.RS 4
+.IP \(bu 8
+BOMs (byte order marks) at the beginning of Perl files
+(scripts, modules) should now be transparently skipped.
+UTF\-16 and UCS\-2 encoded Perl files should now be read correctly.
+.IP \(bu 8
+The character tables have been updated to Unicode 3.2.0.
+.IP \(bu 8
+Comparing with utf8 data does not magically upgrade non\-utf8 data
+into utf8.  (This was a problem for example if you were mixing data
+from I/O and Unicode data: your output might have got magically encoded
+as UTF\-8.)
+.IP \(bu 8
+Generating illegal Unicode code points such as U+FFFE, or the UTF\-16
+surrogates, now also generates an optional warning.
+.IP \(bu 8
+\&\f(CW\*(C`IsAlnum\*(C'\fR, \f(CW\*(C`IsAlpha\*(C'\fR, and \f(CW\*(C`IsWord\*(C'\fR now match titlecase.
+.IP \(bu 8
+Concatenation with the \f(CW\*(C`.\*(C'\fR operator or via variable interpolation,
+\&\f(CW\*(C`eq\*(C'\fR, \f(CW\*(C`substr\*(C'\fR, \f(CW\*(C`reverse\*(C'\fR, \f(CW\*(C`quotemeta\*(C'\fR, the \f(CW\*(C`x\*(C'\fR operator,
+substitution with \f(CW\*(C`s///\*(C'\fR, single-quoted UTF\-8, should now work.
+.IP \(bu 8
+The \f(CW\*(C`tr///\*(C'\fR operator now works.  Note that the \f(CW\*(C`tr///CU\*(C'\fR
+functionality has been removed (but see pack('U0', ...)).
+.IP \(bu 8
+\&\f(CW\*(C`eval "v200"\*(C'\fR now works.
+.IP \(bu 8
+Perl 5.6.0 parsed m/\ex{ab}/ incorrectly, leading to spurious warnings.
+This has been corrected. [561]
+.IP \(bu 8
+Zero entries were missing from the Unicode classes such as \f(CW\*(C`IsDigit\*(C'\fR.
+.RE
+.RS 4
+.RE
+.IP \(bu 4
+Large unsigned numbers (those above 2**31) could sometimes lose their
+unsignedness, causing bogus results in arithmetic operations. [561]
+.IP \(bu 4
+The Perl parser has been stress tested using both random input and
+Markov chain input and the few found crashes and lockups have been
+fixed.
+.SS "Platform Specific Changes and Fixes"
+.IX Subsection "Platform Specific Changes and Fixes"
+.IP \(bu 4
+BSDI 4.*
+.Sp
+Perl now works on post\-4.0 BSD/OSes.
+.IP \(bu 4
+All BSDs
+.Sp
+Setting \f(CW$0\fR now works (as much as possible; see perlvar for details).
+.IP \(bu 4
+Cygwin
+.Sp
+Numerous updates; currently synchronised with Cygwin 1.3.10.
+.IP \(bu 4
+Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O.
+.IP \(bu 4
+EPOC
+.Sp
+EPOC now better supported.  See README.epoc. [561]
+.IP \(bu 4
+FreeBSD 3.*
+.Sp
+Perl now works on post\-3.0 FreeBSDs.
+.IP \(bu 4
+HP-UX
+.Sp
+README.hpux updated; \f(CW\*(C`Configure \-Duse64bitall\*(C'\fR now works;
+now uses HP-UX malloc instead of Perl malloc.
+.IP \(bu 4
+IRIX
+.Sp
+Numerous compilation flag and hint enhancements; accidental mixing
+of 32\-bit and 64\-bit libraries (a doomed attempt) made much harder.
+.IP \(bu 4
+Linux
+.RS 4
+.IP \(bu 8
+Long doubles should now work (see INSTALL). [561]
+.IP \(bu 8
+Linux previously had problems related to sockaddrlen when using
+\&\fBaccept()\fR, \fBrecvfrom()\fR (in Perl: \fBrecv()\fR), \fBgetpeername()\fR, and
+\&\fBgetsockname()\fR.
+.RE
+.RS 4
+.RE
+.IP \(bu 4
+Mac OS Classic
+.Sp
+Compilation of the standard Perl distribution in Mac OS Classic should
+now work if you have the Metrowerks development environment and the
+missing Mac-specific toolkit bits.  Contact the macperl mailing list
+for details.
+.IP \(bu 4
+MPE/iX
+.Sp
+MPE/iX update after Perl 5.6.0.  See README.mpeix. [561]
+.IP \(bu 4
+NetBSD/threads: try installing the GNU pth (should be in the
+packages collection, or http://www.gnu.org/software/pth/),
+and Configure with \-Duseithreads.
+.IP \(bu 4
+NetBSD/sparc
+.Sp
+Perl now works on NetBSD/sparc.
+.IP \(bu 4
+OS/2
+.Sp
+Now works with usethreads (see INSTALL). [561]
+.IP \(bu 4
+Solaris
+.Sp
+64\-bitness using the Sun Workshop compiler now works.
+.IP \(bu 4
+Stratus VOS
+.Sp
+The native build method requires at least VOS Release 14.5.0
+and GNU C++/GNU Tools 2.0.1 or later.  The Perl pack function
+now maps overflowed values to +infinity and underflowed values
+to \-infinity.
+.IP \(bu 4
+Tru64 (aka Digital UNIX, aka DEC OSF/1)
+.Sp
+The operating system version letter now recorded in \f(CW$Config\fR{osvers}.
+Allow compiling with gcc (previously explicitly forbidden).  Compiling
+with gcc still not recommended because buggy code results, even with
+gcc 2.95.2.
+.IP \(bu 4
+Unicos
+.Sp
+Fixed various alignment problems that lead into core dumps either
+during build or later; no longer dies on math errors at runtime;
+now using full quad integers (64 bits), previously was using
+only 46 bit integers for speed.
+.IP \(bu 4
+VMS
+.Sp
+See "Socket Extension Dynamic in VMS" and "IEEE-format Floating Point
+Default on OpenVMS Alpha" for important changes not otherwise listed here.
+.Sp
+\&\fBchdir()\fR now works better despite a CRT bug; now works with MULTIPLICITY
+(see INSTALL); now works with Perl's malloc.
+.Sp
+The tainting of \f(CW%ENV\fR elements via \f(CW\*(C`keys\*(C'\fR or \f(CW\*(C`values\*(C'\fR was previously
+unimplemented.  It now works as documented.
+.Sp
+The \f(CW\*(C`waitpid\*(C'\fR emulation has been improved.  The worst bug (now fixed)
+was that a pid of \-1 would cause a wildcard search of all processes on
+the system.
+.Sp
+POSIX-style signals are now emulated much better on VMS versions prior
+to 7.0.
+.Sp
+The \f(CW\*(C`system\*(C'\fR function and backticks operator have improved
+functionality and better error handling. [561]
+.Sp
+File access tests now use current process privileges rather than the
+user's default privileges, which could sometimes result in a mismatch
+between reported access and actual access.  This improvement is only
+available on VMS v6.0 and later.
+.Sp
+There is a new \f(CW\*(C`kill\*(C'\fR implementation based on \f(CW\*(C`sys$sigprc\*(C'\fR that allows
+older VMS systems (pre\-7.0) to use \f(CW\*(C`kill\*(C'\fR to send signals rather than
+simply force exit.  This implementation also allows later systems to
+call \f(CW\*(C`kill\*(C'\fR from within a signal handler.
+.Sp
+Iterative logical name translations are now limited to 10 iterations in
+imitation of SHOW LOGICAL and other OpenVMS facilities.
+.IP \(bu 4
+Windows
+.RS 4
+.IP \(bu 8
+Signal handling now works better than it used to.  It is now implemented
+using a Windows message loop, and is therefore less prone to random
+crashes.
+.IP \(bu 8
+\&\fBfork()\fR emulation is now more robust, but still continues to have a few
+esoteric bugs and caveats.  See perlfork for details. [561+]
+.IP \(bu 8
+A failed (pseudo)fork now returns undef and sets errno to EAGAIN. [561]
+.IP \(bu 8
+The following modules now work on Windows:
+.Sp
+.Vb 4
+\&    ExtUtils::Embed         [561]
+\&    IO::Pipe
+\&    IO::Poll
+\&    Net::Ping
+.Ve
+.IP \(bu 8
+\&\fBIO::File::new_tmpfile()\fR is no longer limited to 32767 invocations
+per-process.
+.IP \(bu 8
+Better \fBchdir()\fR return value for a non-existent directory.
+.IP \(bu 8
+Compiling perl using the 64\-bit Platform SDK tools is now supported.
+.IP \(bu 8
+The \fBWin32::SetChildShowWindow()\fR builtin can be used to control the
+visibility of windows created by child processes.  See Win32 for
+details.
+.IP \(bu 8
+Non-blocking waits for child processes (or pseudo-processes) are
+supported via \f(CW\*(C`waitpid($pid, &POSIX::WNOHANG)\*(C'\fR.
+.IP \(bu 8
+The behavior of \fBsystem()\fR with multiple arguments has been rationalized.
+Each unquoted argument will be automatically quoted to protect whitespace,
+and any existing whitespace in the arguments will be preserved.  This
+improves the portability of system(@args) by avoiding the need for
+Windows \f(CW\*(C`cmd\*(C'\fR shell specific quoting in perl programs.
+.Sp
+Note that this means that some scripts that may have relied on earlier
+buggy behavior may no longer work correctly.  For example,
+\&\f(CW\*(C`system("nmake /nologo", @args)\*(C'\fR will now attempt to run the file
+\&\f(CW\*(C`nmake /nologo\*(C'\fR and will fail when such a file isn't found.
+On the other hand, perl will now execute code such as
+\&\f(CW\*(C`system("c:/Program Files/MyApp/foo.exe", @args)\*(C'\fR correctly.
+.IP \(bu 8
+The perl header files no longer suppress common warnings from the
+Microsoft Visual C++ compiler.  This means that additional warnings may
+now show up when compiling XS code.
+.IP \(bu 8
+Borland C++ v5.5 is now a supported compiler that can build Perl.
+However, the generated binaries continue to be incompatible with those
+generated by the other supported compilers (GCC and Visual C++). [561]
+.IP \(bu 8
+Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x.
+[561]
+.IP \(bu 8
+Current directory entries in \f(CW%ENV\fR are now correctly propagated to child
+processes. [561]
+.IP \(bu 8
+New \f(CW%ENV\fR entries now propagate to subprocesses. [561]
+.IP \(bu 8
+\&\fBWin32::GetCwd()\fR correctly returns C:\e instead of C: when at the drive root.
+Other bugs in \fBchdir()\fR and \fBCwd::cwd()\fR have also been fixed. [561]
+.IP \(bu 8
+The makefiles now default to the features enabled in ActiveState ActivePerl
+(a popular Win32 binary distribution). [561]
+.IP \(bu 8
+HTML files will now be installed in c:\eperl\ehtml instead of
+c:\eperl\elib\epod\ehtml
+.IP \(bu 8
+REG_EXPAND_SZ keys are now allowed in registry settings used by perl. [561]
+.IP \(bu 8
+Can now \fBsend()\fR from all threads, not just the first one. [561]
+.IP \(bu 8
+ExtUtils::MakeMaker now uses \f(CW$ENV\fR{LIB} to search for libraries. [561]
+.IP \(bu 8
+Less stack reserved per thread so that more threads can run
+concurrently. (Still 16M per thread.) [561]
+.IP \(bu 8
+\&\f(CW\*(C`File::Spec\->tmpdir()\*(C'\fR now prefers C:/temp over /tmp
+(works better when perl is running as service).
+.IP \(bu 8
+Better UNC path handling under ithreads. [561]
+.IP \(bu 8
+\&\fBwait()\fR, \fBwaitpid()\fR, and backticks now return the correct exit status
+under Windows 9x. [561]
+.IP \(bu 8
+A socket handle leak in \fBaccept()\fR has been fixed. [561]
+.RE
+.RS 4
+.RE
+.SH "New or Changed Diagnostics"
+.IX Header "New or Changed Diagnostics"
+Please see perldiag for more details.
+.IP \(bu 4
+Ambiguous range in the transliteration operator (like a\-z\-9) now
+gives a warning.
+.IP \(bu 4
+chdir("") and chdir(undef) now give a deprecation warning because they
+cause a possible unintentional chdir to the home directory.
+Say \fBchdir()\fR if you really mean that.
+.IP \(bu 4
+Two new debugging options have been added: if you have compiled your
+Perl with debugging, you can use the \-DT [561] and \-DR options to trace
+tokenising and to add reference counts to displaying variables,
+respectively.
+.IP \(bu 4
+The lexical warnings category "deprecated" is no longer a sub-category
+of the "syntax" category. It is now a top-level category in its own
+right.
+.IP \(bu 4
+Unadorned \fBdump()\fR will now give a warning suggesting to
+use explicit \fBCORE::dump()\fR if that's what really is meant.
+.IP \(bu 4
+The "Unrecognized escape" warning has been extended to include \f(CW\*(C`\e8\*(C'\fR,
+\&\f(CW\*(C`\e9\*(C'\fR, and \f(CW\*(C`\e_\*(C'\fR.  There is no need to escape any of the \f(CW\*(C`\ew\*(C'\fR characters.
+.IP \(bu 4
+All regular expression compilation error messages are now hopefully
+easier to understand both because the error message now comes before
+the failed regex and because the point of failure is now clearly
+marked by a \f(CW\*(C`<\-\- HERE\*(C'\fR marker.
+.IP \(bu 4
+Various I/O (and socket) functions like \fBbinmode()\fR, \fBclose()\fR, and so
+forth now more consistently warn if they are used illogically either
+on a yet unopened or on an already closed filehandle (or socket).
+.IP \(bu 4
+Using \fBlstat()\fR on a filehandle now gives a warning.  (It's a non-sensical
+thing to do.)
+.IP \(bu 4
+The \f(CW\*(C`\-M\*(C'\fR and \f(CW\*(C`\-m\*(C'\fR options now warn if you didn't supply the module name.
+.IP \(bu 4
+If you in \f(CW\*(C`use\*(C'\fR specify a required minimum version, modules matching
+the name and but not defining a \f(CW$VERSION\fR will cause a fatal failure.
+.IP \(bu 4
+Using negative offset for \fBvec()\fR in lvalue context is now a warnable offense.
+.IP \(bu 4
+Odd number of arguments to overload::constant now elicits a warning.
+.IP \(bu 4
+Odd number of elements in anonymous hash now elicits a warning.
+.IP \(bu 4
+The various "opened only for", "on closed", "never opened" warnings
+drop the \f(CW\*(C`main::\*(C'\fR prefix for filehandles in the \f(CW\*(C`main\*(C'\fR package,
+for example \f(CW\*(C`STDIN\*(C'\fR instead of \f(CW\*(C`main::STDIN\*(C'\fR.
+.IP \(bu 4
+Subroutine prototypes are now checked more carefully, you may
+get warnings for example if you have used non-prototype characters.
+.IP \(bu 4
+If an attempt to use a (non-blessed) reference as an array index
+is made, a warning is given.
+.IP \(bu 4
+\&\f(CW\*(C`push @a;\*(C'\fR and \f(CW\*(C`unshift @a;\*(C'\fR (with no values to push or unshift)
+now give a warning.  This may be a problem for generated and eval'ed
+code.
+.IP \(bu 4
+If you try to "pack" in perlfunc a number less than 0 or larger than 255
+using the \f(CW"C"\fR format you will get an optional warning.  Similarly
+for the \f(CW"c"\fR format and a number less than \-128 or more than 127.
+.IP \(bu 4
+pack \f(CW\*(C`P\*(C'\fR format now demands an explicit size.
+.IP \(bu 4
+unpack \f(CW\*(C`w\*(C'\fR now warns of unterminated compressed integers.
+.IP \(bu 4
+Warnings relating to the use of PerlIO have been added.
+.IP \(bu 4
+Certain regex modifiers such as \f(CW\*(C`(?o)\*(C'\fR make sense only if applied to
+the entire regex.  You will get an optional warning if you try to do
+otherwise.
+.IP \(bu 4
+Variable length lookbehind has not yet been implemented, trying to
+use it will tell that.
+.IP \(bu 4
+Using arrays or hashes as references (e.g. \f(CW\*(C`%foo\->{bar}\*(C'\fR
+has been deprecated for a while.  Now you will get an optional warning.
+.IP \(bu 4
+Warnings relating to the use of the new restricted hashes feature
+have been added.
+.IP \(bu 4
+Self-ties of arrays and hashes are not supported and fatal errors
+will happen even at an attempt to do so.
+.IP \(bu 4
+Using \f(CW\*(C`sort\*(C'\fR in scalar context now issues an optional warning.
+This didn't do anything useful, as the sort was not performed.
+.IP \(bu 4
+Using the /g modifier in \fBsplit()\fR is meaningless and will cause a warning.
+.IP \(bu 4
+Using \fBsplice()\fR past the end of an array now causes a warning.
+.IP \(bu 4
+Malformed Unicode encodings (UTF\-8 and UTF\-16) cause a lot of warnings,
+as does trying to use UTF\-16 surrogates (which are unimplemented).
+.IP \(bu 4
+Trying to use Unicode characters on an I/O stream without marking the
+stream's encoding (using \fBopen()\fR or \fBbinmode()\fR) will cause "Wide character"
+warnings.
+.IP \(bu 4
+Use of v\-strings in use/require causes a (backward) portability warning.
+.IP \(bu 4
+Warnings relating to the use interpreter threads and their shared data
+have been added.
+.SH "Changed Internals"
+.IX Header "Changed Internals"
+.IP \(bu 4
+PerlIO is now the default.
+.IP \(bu 4
+perlapi.pod (a companion to perlguts) now attempts to document the
+internal API.
+.IP \(bu 4
+You can now build a really minimal perl called microperl.
+Building microperl does not require even running Configure;
+\&\f(CW\*(C`make \-f Makefile.micro\*(C'\fR should be enough.  Beware: microperl makes
+many assumptions, some of which may be too bold; the resulting
+executable may crash or otherwise misbehave in wondrous ways.
+For careful hackers only.
+.IP \(bu 4
+Added \fBrsignal()\fR, \fBwhichsig()\fR, \fBdo_join()\fR, op_clear, op_null,
+\&\fBptr_table_clear()\fR, \fBptr_table_free()\fR, \fBsv_setref_uv()\fR, and several UTF\-8
+interfaces to the publicised API.  For the full list of the available
+APIs see perlapi.
+.IP \(bu 4
+Made possible to propagate customised exceptions via \fBcroak()\fRing.
+.IP \(bu 4
+Now xsubs can have attributes just like subs.  (Well, at least the
+built-in attributes.)
+.IP \(bu 4
+dTHR and djSP have been obsoleted; the former removed (because it's
+a no-op) and the latter replaced with dSP.
+.IP \(bu 4
+PERL_OBJECT has been completely removed.
+.IP \(bu 4
+The MAGIC constants (e.g. \f(CW\*(AqP\*(Aq\fR) have been macrofied
+(e.g. \f(CW\*(C`PERL_MAGIC_TIED\*(C'\fR) for better source code readability
+and maintainability.
+.IP \(bu 4
+The regex compiler now maintains a structure that identifies nodes in
+the compiled bytecode with the corresponding syntactic features of the
+original regex expression.  The information is attached to the new
+\&\f(CW\*(C`offsets\*(C'\fR member of the \f(CW\*(C`struct regexp\*(C'\fR. See perldebguts for more
+complete information.
+.IP \(bu 4
+The C code has been made much more \f(CW\*(C`gcc \-Wall\*(C'\fR clean.  Some warning
+messages still remain in some platforms, so if you are compiling with
+gcc you may see some warnings about dubious practices.  The warnings
+are being worked on.
+.IP \(bu 4
+\&\fIperly.c\fR, \fIsv.c\fR, and \fIsv.h\fR have now been extensively commented.
+.IP \(bu 4
+Documentation on how to use the Perl source repository has been added
+to \fIPorting/repository.pod\fR.
+.IP \(bu 4
+There are now several profiling make targets.
+.SH "Security Vulnerability Closed [561]"
+.IX Header "Security Vulnerability Closed [561]"
+(This change was already made in 5.7.0 but bears repeating here.)
+(5.7.0 came out before 5.6.1: the development branch 5.7 released
+earlier than the maintenance branch 5.6)
+.PP
+A potential security vulnerability in the optional suidperl component
+of Perl was identified in August 2000.  suidperl is neither built nor
+installed by default.  As of November 2001 the only known vulnerable
+platform is Linux, most likely all Linux distributions.  CERT and
+various vendors and distributors have been alerted about the vulnerability.
+See http://www.cpan.org/src/5.0/sperl\-2000\-08\-05/sperl\-2000\-08\-05.txt
+for more information.
+.PP
+The problem was caused by Perl trying to report a suspected security
+exploit attempt using an external program, /bin/mail.  On Linux
+platforms the /bin/mail program had an undocumented feature which
+when combined with suidperl gave access to a root shell, resulting in
+a serious compromise instead of reporting the exploit attempt.  If you
+don't have /bin/mail, or if you have 'safe setuid scripts', or if
+suidperl is not installed, you are safe.
+.PP
+The exploit attempt reporting feature has been completely removed from
+Perl 5.8.0 (and the maintenance release 5.6.1, and it was removed also
+from all the Perl 5.7 releases), so that particular vulnerability
+isn't there anymore.  However, further security vulnerabilities are,
+unfortunately, always possible.  The suidperl functionality is most
+probably going to be removed in Perl 5.10.  In any case, suidperl
+should only be used by security experts who know exactly what they are
+doing and why they are using suidperl instead of some other solution
+such as sudo ( see http://www.courtesan.com/sudo/ ).
+.SH "New Tests"
+.IX Header "New Tests"
+Several new tests have been added, especially for the \fIlib\fR and
+\&\fIext\fR subsections.  There are now about 69 000 individual tests
+(spread over about 700 test scripts), in the regression suite (5.6.1
+has about 11 700 tests, in 258 test scripts)  The exact numbers depend
+on the platform and Perl configuration used.  Many of the new tests
+are of course introduced by the new modules, but still in general Perl
+is now more thoroughly tested.
+.PP
+Because of the large number of tests, running the regression suite
+will take considerably longer time than it used to: expect the suite
+to take up to 4\-5 times longer to run than in perl 5.6.  On a really
+fast machine you can hope to finish the suite in about 6\-8 minutes
+(wallclock time).
+.PP
+The tests are now reported in a different order than in earlier Perls.
+(This happens because the test scripts from under t/lib have been moved
+to be closer to the library/extension they are testing.)
+.SH "Known Problems"
+.IX Header "Known Problems"
+.SS "The Compiler Suite Is Still Very Experimental"
+.IX Subsection "The Compiler Suite Is Still Very Experimental"
+The compiler suite is slowly getting better but it continues to be
+highly experimental.  Use in production environments is discouraged.
+.SS "Localising Tied Arrays and Hashes Is Broken"
+.IX Subsection "Localising Tied Arrays and Hashes Is Broken"
+.Vb 1
+\&    local %tied_array;
+.Ve
+.PP
+doesn't work as one would expect: the old value is restored
+incorrectly.  This will be changed in a future release, but we don't
+know yet what the new semantics will exactly be.  In any case, the
+change will break existing code that relies on the current
+(ill-defined) semantics, so just avoid doing this in general.
+.SS "Building Extensions Can Fail Because Of Largefiles"
+.IX Subsection "Building Extensions Can Fail Because Of Largefiles"
+Some extensions like mod_perl are known to have issues with
+`largefiles', a change brought by Perl 5.6.0 in which file offsets
+default to 64 bits wide, where supported.  Modules may fail to compile
+at all, or they may compile and work incorrectly.  Currently, there
+is no good solution for the problem, but Configure now provides
+appropriate non-largefile ccflags, ldflags, libswanted, and libs
+in the \f(CW%Config\fR hash (e.g., \f(CW$Config\fR{ccflags_nolargefiles}) so the
+extensions that are having problems can try configuring themselves
+without the largefileness.  This is admittedly not a clean solution,
+and the solution may not even work at all.  One potential failure is
+whether one can (or, if one can, whether it's a good idea to) link
+together at all binaries with different ideas about file offsets;
+all this is platform-dependent.
+.ie n .SS "Modifying $_ Inside for(..)"
+.el .SS "Modifying \f(CW$_\fP Inside for(..)"
+.IX Subsection "Modifying $_ Inside for(..)"
+.Vb 1
+\&   for (1..5) { $_++ }
+.Ve
+.PP
+works without complaint.  It shouldn't.  (You should be able to
+modify only lvalue elements inside the loops.)  You can see the
+correct behaviour by replacing the 1..5 with 1, 2, 3, 4, 5.
+.SS "mod_perl 1.26 Doesn't Build With Threaded Perl"
+.IX Subsection "mod_perl 1.26 Doesn't Build With Threaded Perl"
+Use mod_perl 1.27 or higher.
+.SS "lib/ftmp\-security tests warn 'system possibly insecure'"
+.IX Subsection "lib/ftmp-security tests warn 'system possibly insecure'"
+Don't panic.  Read the 'make test' section of INSTALL instead.
+.SS "libwww-perl (LWP) fails base/date #51"
+.IX Subsection "libwww-perl (LWP) fails base/date #51"
+Use libwww-perl 5.65 or later.
+.SS "PDL failing some tests"
+.IX Subsection "PDL failing some tests"
+Use PDL 2.3.4 or later.
+.SS Perl_get_sv
+.IX Subsection "Perl_get_sv"
+You may get errors like 'Undefined symbol "Perl_get_sv"' or "can't
+resolve symbol 'Perl_get_sv'", or the symbol may be "Perl_sv_2pv".
+This probably means that you are trying to use an older shared Perl
+library (or extensions linked with such) with Perl 5.8.0 executable.
+Perl used to have such a subroutine, but that is no more the case.
+Check your shared library path, and any shared Perl libraries in those
+directories.
+.PP
+Sometimes this problem may also indicate a partial Perl 5.8.0
+installation, see "Mac OS X dyld undefined symbols" for an
+example and how to deal with it.
+.SS "Self-tying Problems"
+.IX Subsection "Self-tying Problems"
+Self-tying of arrays and hashes is broken in rather deep and
+hard-to-fix ways.  As a stop-gap measure to avoid people from getting
+frustrated at the mysterious results (core dumps, most often), it is
+forbidden for now (you will get a fatal error even from an attempt).
+.PP
+A change to self-tying of globs has caused them to be recursively
+referenced (see: "Two-Phased Garbage Collection" in perlobj).  You
+will now need an explicit untie to destroy a self-tied glob.  This
+behaviour may be fixed at a later date.
+.PP
+Self-tying of scalars and IO thingies works.
+.SS ext/threads/t/libc
+.IX Subsection "ext/threads/t/libc"
+If this test fails, it indicates that your libc (C library) is not
+threadsafe.  This particular test stress tests the \fBlocaltime()\fR call to
+find out whether it is threadsafe.  See perlthrtut for more information.
+.SS "Failure of Thread (5.005\-style) tests"
+.IX Subsection "Failure of Thread (5.005-style) tests"
+\&\fBNote that support for 5.005\-style threading is deprecated,
+experimental and practically unsupported.  In 5.10, it is expected
+to be removed.  You should migrate your code to ithreads.\fR
+.PP
+The following tests are known to fail due to fundamental problems in
+the 5.005 threading implementation. These are not new failures\-\-Perl
+5.005_0x has the same bugs, but didn't have these tests.
+.PP
+.Vb 10
+\& ../ext/B/t/xref.t                    255 65280    14   12  85.71%  3\-14
+\& ../ext/List/Util/t/first.t           255 65280     7    4  57.14%  2 5\-7
+\& ../lib/English.t                       2   512    54    2   3.70%  2\-3
+\& ../lib/FileCache.t                                 5    1  20.00%  5
+\& ../lib/Filter/Simple/t/data.t                      6    3  50.00%  1\-3
+\& ../lib/Filter/Simple/t/filter_only.                9    3  33.33%  1\-2 5
+\& ../lib/Math/BigInt/t/bare_mbf.t                 1627    4   0.25%  8 11 1626\-1627
+\& ../lib/Math/BigInt/t/bigfltpm.t                 1629    4   0.25%  10 13 1628\-
+\&                                                                    1629
+\& ../lib/Math/BigInt/t/sub_mbf.t                  1633    4   0.24%  8 11 1632\-1633
+\& ../lib/Math/BigInt/t/with_sub.t                 1628    4   0.25%  9 12 1627\-1628
+\& ../lib/Tie/File/t/31_autodefer.t     255 65280    65   32  49.23%  34\-65
+\& ../lib/autouse.t                                  10    1  10.00%  4
+\& op/flip.t                                         15    1   6.67%  15
+.Ve
+.PP
+These failures are unlikely to get fixed as 5.005\-style threads
+are considered fundamentally broken.  (Basically what happens is that
+competing threads can corrupt shared global state, one good example
+being regular expression engine's state.)
+.SS "Timing problems"
+.IX Subsection "Timing problems"
+The following tests may fail intermittently because of timing
+problems, for example if the system is heavily loaded.
+.PP
+.Vb 5
+\&    t/op/alarm.t
+\&    ext/Time/HiRes/HiRes.t
+\&    lib/Benchmark.t
+\&    lib/Memoize/t/expmod_t.t
+\&    lib/Memoize/t/speed.t
+.Ve
+.PP
+In case of failure please try running them manually, for example
+.PP
+.Vb 1
+\&    ./perl \-Ilib ext/Time/HiRes/HiRes.t
+.Ve
+.SS "Tied/Magical Array/Hash Elements Do Not Autovivify"
+.IX Subsection "Tied/Magical Array/Hash Elements Do Not Autovivify"
+For normal arrays \f(CW\*(C`$foo = \e$bar[1]\*(C'\fR will assign \f(CW\*(C`undef\*(C'\fR to
+\&\f(CW$bar[1]\fR (assuming that it didn't exist before), but for
+tied/magical arrays and hashes such autovivification does not happen
+because there is currently no way to catch the reference creation.
+The same problem affects slicing over non-existent indices/keys of
+a tied/magical array/hash.
+.SS "Unicode in package/class and subroutine names does not work"
+.IX Subsection "Unicode in package/class and subroutine names does not work"
+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 "Platform Specific Problems"
+.IX Header "Platform Specific Problems"
+.SS AIX
+.IX Subsection "AIX"
+.IP \(bu 4
+If using the AIX native make command, instead of just "make" issue
+"make all".  In some setups the former has been known to spuriously
+also try to run "make install".  Alternatively, you may want to use
+GNU make.
+.IP \(bu 4
+In AIX 4.2, Perl extensions that use C++ functions that use statics
+may have problems in that the statics are not getting initialized.
+In newer AIX releases, this has been solved by linking Perl with
+the libC_r library, but unfortunately in AIX 4.2 the said library
+has an obscure bug where the various functions related to time
+(such as \fBtime()\fR and \fBgettimeofday()\fR) return broken values, and
+therefore in AIX 4.2 Perl is not linked against libC_r.
+.IP \(bu 4
+vac 5.0.0.0 May Produce Buggy Code For Perl
+.Sp
+The AIX C compiler vac version 5.0.0.0 may produce buggy code,
+resulting in a few random tests failing when run as part of "make
+test", but when the failing tests are run by hand, they succeed.
+We suggest upgrading to at least vac version 5.0.1.0, that has been
+known to compile Perl correctly.  "lslpp \-L|grep vac.C" will tell
+you the vac version.  See README.aix.
+.IP \(bu 4
+If building threaded Perl, you may get compilation warning from pp_sys.c:
+.Sp
+.Vb 1
+\&  "pp_sys.c", line 4651.39: 1506\-280 (W) Function argument assignment between types "unsigned char*" and "const void*" is not allowed.
+.Ve
+.Sp
+This is harmless; it is caused by the \fBgetnetbyaddr()\fR and \fBgetnetbyaddr_r()\fR
+having slightly different types for their first argument.
+.SS "Alpha systems with old gccs fail several tests"
+.IX Subsection "Alpha systems with old gccs fail several tests"
+If you see op/pack, op/pat, op/regexp, or ext/Storable tests failing
+in a Linux/alpha or *BSD/Alpha, it's probably time to upgrade your gcc.
+gccs prior to 2.95.3 are definitely not good enough, and gcc 3.1 may
+be even better.  (RedHat Linux/alpha with gcc 3.1 reported no problems,
+as did Linux 2.4.18 with gcc 2.95.4.)  (In Tru64, it is preferable to
+use the bundled C compiler.)
+.SS AmigaOS
+.IX Subsection "AmigaOS"
+Perl 5.8.0 doesn't build in AmigaOS.  It broke at some point during
+the ithreads work and we could not find Amiga experts to unbreak the
+problems.  Perl 5.6.1 still works for AmigaOS (as does the 5.7.2
+development release).
+.SS BeOS
+.IX Subsection "BeOS"
+The following tests fail on 5.8.0 Perl in BeOS Personal 5.03:
+.PP
+.Vb 6
+\& t/op/lfs............................FAILED at test 17
+\& t/op/magic..........................FAILED at test 24
+\& ext/Fcntl/t/syslfs..................FAILED at test 17
+\& ext/File/Glob/t/basic...............FAILED at test 3
+\& ext/POSIX/t/sigaction...............FAILED at test 13
+\& ext/POSIX/t/waitpid.................FAILED at test 1
+.Ve
+.PP
+(\fBNote:\fR more information was available in \fIREADME.beos\fR until support for
+BeOS was removed in Perl v5.18.0)
+.SS "Cygwin ""unable to remap"""
+.IX Subsection "Cygwin ""unable to remap"""
+For example when building the Tk extension for Cygwin,
+you may get an error message saying "unable to remap".
+This is known problem with Cygwin, and a workaround is
+detailed in here: http://sources.redhat.com/ml/cygwin/2001\-12/msg00894.html
+.SS "Cygwin ndbm tests fail on FAT"
+.IX Subsection "Cygwin ndbm tests fail on FAT"
+One can build but not install (or test the build of) the NDBM_File
+on FAT filesystems.  Installation (or build) on NTFS works fine.
+If one attempts the test on a FAT install (or build) the following
+failures are expected:
+.PP
+.Vb 6
+\& ../ext/NDBM_File/ndbm.t       13  3328    71   59  83.10%  1\-2 4 16\-71
+\& ../ext/ODBM_File/odbm.t      255 65280    ??   ??       %  ??
+\& ../lib/AnyDBM_File.t           2   512    12    2  16.67%  1 4
+\& ../lib/Memoize/t/errors.t      0   139    11    5  45.45%  7\-11
+\& ../lib/Memoize/t/tie_ndbm.t   13  3328     4    4 100.00%  1\-4
+\& run/fresh_perl.t                          97    1   1.03%  91
+.Ve
+.PP
+NDBM_File fails and ODBM_File just coredumps.
+.PP
+If you intend to run only on FAT (or if using AnyDBM_File on FAT),
+run Configure with the \-Ui_ndbm and \-Ui_dbm options to prevent
+NDBM_File and ODBM_File being built.
+.SS "DJGPP Failures"
+.IX Subsection "DJGPP Failures"
+.Vb 8
+\& t/op/stat............................FAILED at test 29
+\& lib/File/Find/t/find.................FAILED at test 1
+\& lib/File/Find/t/taint................FAILED at test 1
+\& lib/h2xs.............................FAILED at test 15
+\& lib/Pod/t/eol........................FAILED at test 1
+\& lib/Test/Harness/t/strap\-analyze.....FAILED at test 8
+\& lib/Test/Harness/t/test\-harness......FAILED at test 23
+\& lib/Test/Simple/t/exit...............FAILED at test 1
+.Ve
+.PP
+The above failures are known as of 5.8.0 with native builds with long
+filenames, but there are a few more if running under dosemu because of
+limitations (and maybe bugs) of dosemu:
+.PP
+.Vb 2
+\& t/comp/cpp...........................FAILED at test 3
+\& t/op/inccode.........................(crash)
+.Ve
+.PP
+and a few lib/ExtUtils tests, and several hundred Encode/t/Aliases.t
+failures that work fine with long filenames.  So you really might
+prefer native builds and long filenames.
+.SS "FreeBSD built with ithreads coredumps reading large directories"
+.IX Subsection "FreeBSD built with ithreads coredumps reading large directories"
+This is a known bug in FreeBSD 4.5's \fBreaddir_r()\fR, it has been fixed in
+FreeBSD 4.6 (see perlfreebsd (README.freebsd)).
+.SS "FreeBSD Failing locale Test 117 For ISO 8859\-15 Locales"
+.IX Subsection "FreeBSD Failing locale Test 117 For ISO 8859-15 Locales"
+The ISO 8859\-15 locales may fail the locale test 117 in FreeBSD.
+This is caused by the characters \exFF (y with diaeresis) and \exBE
+(Y with diaeresis) not behaving correctly when being matched
+case-insensitively.  Apparently this problem has been fixed in
+the latest FreeBSD releases.
+( http://www.freebsd.org/cgi/query\-pr.cgi?pr=34308 )
+.SS "IRIX fails ext/List/Util/t/shuffle.t or Digest::MD5"
+.IX Subsection "IRIX fails ext/List/Util/t/shuffle.t or Digest::MD5"
+IRIX with MIPSpro 7.3.1.2m or 7.3.1.3m compiler may fail the List::Util
+test ext/List/Util/t/shuffle.t by dumping core.  This seems to be
+a compiler error since if compiled with gcc no core dump ensues, and
+no failures have been seen on the said test on any other platform.
+.PP
+Similarly, building the Digest::MD5 extension has been
+known to fail with "*** Termination code 139 (bu21)".
+.PP
+The cure is to drop optimization level (Configure \-Doptimize=\-O2).
+.SS "HP-UX lib/posix Subtest 9 Fails When LP64\-Configured"
+.IX Subsection "HP-UX lib/posix Subtest 9 Fails When LP64-Configured"
+If perl is configured with \-Duse64bitall, the successful result of the
+subtest 10 of lib/posix may arrive before the successful result of the
+subtest 9, which confuses the test harness so much that it thinks the
+subtest 9 failed.
+.SS "Linux with glibc 2.2.5 fails t/op/int subtest #6 with \-Duse64bitint"
+.IX Subsection "Linux with glibc 2.2.5 fails t/op/int subtest #6 with -Duse64bitint"
+This is a known bug in the glibc 2.2.5 with long long integers.
+( http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=65612 )
+.SS "Linux With Sfio Fails op/misc Test 48"
+.IX Subsection "Linux With Sfio Fails op/misc Test 48"
+No known fix.
+.SS "Mac OS X"
+.IX Subsection "Mac OS X"
+Please remember to set your environment variable LC_ALL to "C"
+(setenv LC_ALL C) before running "make test" to avoid a lot of
+warnings about the broken locales of Mac OS X.
+.PP
+The following tests are known to fail in Mac OS X 10.1.5 because of
+buggy (old) implementations of Berkeley DB included in Mac OS X:
+.PP
+.Vb 4
+\& Failed Test                 Stat Wstat Total Fail  Failed  List of Failed
+\& \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
+\& ../ext/DB_File/t/db\-btree.t    0    11    ??   ??       %  ??
+\& ../ext/DB_File/t/db\-recno.t              149    3   2.01%  61 63 65
+.Ve
+.PP
+If you are building on a UFS partition, you will also probably see
+t/op/stat.t subtest #9 fail.  This is caused by Darwin's UFS not
+supporting inode change time.
+.PP
+Also the ext/POSIX/t/posix.t subtest #10 fails but it is skipped for
+now because the failure is Apple's fault, not Perl's (blocked signals
+are lost).
+.PP
+If you Configure with ithreads, ext/threads/t/libc.t will fail. Again,
+this is not Perl's fault\-\- the libc of Mac OS X is not threadsafe
+(in this particular test, the \fBlocaltime()\fR call is found to be
+threadunsafe.)
+.SS "Mac OS X dyld undefined symbols"
+.IX Subsection "Mac OS X dyld undefined symbols"
+If after installing Perl 5.8.0 you are getting warnings about missing
+symbols, for example
+.PP
+.Vb 3
+\&    dyld: perl Undefined symbols
+\&    _perl_sv_2pv
+\&    _perl_get_sv
+.Ve
+.PP
+you probably have an old pre\-Perl\-5.8.0 installation (or parts of one)
+in /Library/Perl (the undefined symbols used to exist in pre\-5.8.0 Perls).
+It seems that for some reason "make install" doesn't always completely
+overwrite the files in /Library/Perl.  You can move the old Perl
+shared library out of the way like this:
+.PP
+.Vb 2
+\&    cd /Library/Perl/darwin/CORE
+\&    mv libperl.dylib libperlold.dylib
+.Ve
+.PP
+and then reissue "make install".  Note that the above of course is
+extremely disruptive for anything using the /usr/local/bin/perl.
+If that doesn't help, you may have to try removing all the .bundle
+files from beneath /Library/Perl, and again "make install"\-ing.
+.SS "OS/2 Test Failures"
+.IX Subsection "OS/2 Test Failures"
+The following tests are known to fail on OS/2 (for clarity
+only the failures are shown, not the full error messages):
+.PP
+.Vb 6
+\& ../lib/ExtUtils/t/Mkbootstrap.t    1   256    18    1   5.56%  8
+\& ../lib/ExtUtils/t/Packlist.t       1   256    34    1   2.94%  17
+\& ../lib/ExtUtils/t/basic.t          1   256    17    1   5.88%  14
+\& lib/os2_process.t                  2   512   227    2   0.88%  174 209
+\& lib/os2_process_kid.t                        227    2   0.88%  174 209
+\& lib/rx_cmprt.t                   255 65280    18    3  16.67%  16\-18
+.Ve
+.SS "op/sprintf tests 91, 129, and 130"
+.IX Subsection "op/sprintf tests 91, 129, and 130"
+The op/sprintf tests 91, 129, and 130 are known to fail on some platforms.
+Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX.
+.PP
+Test 91 is known to fail on QNX6 (nto), because \f(CW\*(C`sprintf \*(Aq%e\*(Aq,0\*(C'\fR
+incorrectly produces \f(CW0.000000e+0\fR instead of \f(CW0.000000e+00\fR.
+.PP
+For tests 129 and 130, the failing platforms do not comply with
+the ANSI C Standard: lines 19ff on page 134 of ANSI X3.159 1989, to
+be exact.  (They produce something other than "1" and "\-1" when
+formatting 0.6 and \-0.6 using the printf format "%.0f"; most often,
+they produce "0" and "\-0".)
+.SS SCO
+.IX Subsection "SCO"
+The socketpair tests are known to be unhappy in SCO 3.2v5.0.4:
+.PP
+.Vb 1
+\& ext/Socket/socketpair.t...............FAILED tests 15\-45
+.Ve
+.SS "Solaris 2.5"
+.IX Subsection "Solaris 2.5"
+In case you are still using Solaris 2.5 (aka SunOS 5.5), you may
+experience failures (the test core dumping) in lib/locale.t.
+The suggested cure is to upgrade your Solaris.
+.SS "Solaris x86 Fails Tests With \-Duse64bitint"
+.IX Subsection "Solaris x86 Fails Tests With -Duse64bitint"
+The following tests are known to fail in Solaris x86 with Perl
+configured to use 64 bit integers:
+.PP
+.Vb 2
+\& ext/Data/Dumper/t/dumper.............FAILED at test 268
+\& ext/Devel/Peek/Peek..................FAILED at test 7
+.Ve
+.SS "SUPER-UX (NEC SX)"
+.IX Subsection "SUPER-UX (NEC SX)"
+The following tests are known to fail on SUPER-UX:
+.PP
+.Vb 11
+\& op/64bitint...........................FAILED tests 29\-30, 32\-33, 35\-36
+\& op/arith..............................FAILED tests 128\-130
+\& op/pack...............................FAILED tests 25\-5625
+\& op/pow................................
+\& op/taint..............................# msgsnd failed
+\& ../ext/IO/lib/IO/t/io_poll............FAILED tests 3\-4
+\& ../ext/IPC/SysV/ipcsysv...............FAILED tests 2, 5\-6
+\& ../ext/IPC/SysV/t/msg.................FAILED tests 2, 4\-6
+\& ../ext/Socket/socketpair..............FAILED tests 12
+\& ../lib/IPC/SysV.......................FAILED tests 2, 5\-6
+\& ../lib/warnings.......................FAILED tests 115\-116, 118\-119
+.Ve
+.PP
+The op/pack failure ("Cannot compress negative numbers at op/pack.t line 126")
+is serious but as of yet unsolved.  It points at some problems with the
+signedness handling of the C compiler, as do the 64bitint, arith, and pow
+failures.  Most of the rest point at problems with SysV IPC.
+.SS "Term::ReadKey not working on Win32"
+.IX Subsection "Term::ReadKey not working on Win32"
+Use Term::ReadKey 2.20 or later.
+.SS UNICOS/mk
+.IX Subsection "UNICOS/mk"
+.IP \(bu 4
+During Configure, the test
+.Sp
+.Vb 1
+\&    Guessing which symbols your C compiler and preprocessor define...
+.Ve
+.Sp
+will probably fail with error messages like
+.Sp
+.Vb 2
+\&    CC\-20 cc: ERROR File = try.c, Line = 3
+\&      The identifier "bad" is undefined.
+\&
+\&      bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
+\&      ^
+\&
+\&    CC\-65 cc: ERROR File = try.c, Line = 3
+\&      A semicolon is expected at this point.
+.Ve
+.Sp
+This is caused by a bug in the awk utility of UNICOS/mk.  You can ignore
+the error, but it does cause a slight problem: you cannot fully
+benefit from the h2ph utility (see h2ph) that can be used to
+convert C headers to Perl libraries, mainly used to be able to access
+from Perl the constants defined using C preprocessor, cpp.  Because of
+the above error, parts of the converted headers will be invisible.
+Luckily, these days the need for h2ph is rare.
+.IP \(bu 4
+If building Perl with interpreter threads (ithreads), the
+\&\fBgetgrent()\fR, \fBgetgrnam()\fR, and \fBgetgrgid()\fR functions cannot return the
+list of the group members due to a bug in the multithreaded support of
+UNICOS/mk.  What this means is that in list context the functions will
+return only three values, not four.
+.SS UTS
+.IX Subsection "UTS"
+There are a few known test failures.  (\fBNote:\fR the relevant information was
+available in \fIREADME.uts\fR until support for UTS was removed in Perl
+v5.18.0)
+.SS "VOS (Stratus)"
+.IX Subsection "VOS (Stratus)"
+When Perl is built using the native build process on VOS Release
+14.5.0 and GNU C++/GNU Tools 2.0.1, all attempted tests either
+pass or result in TODO (ignored) failures.
+.SS VMS
+.IX Subsection "VMS"
+There should be no reported test failures with a default configuration,
+though there are a number of tests marked TODO that point to areas
+needing further debugging and/or porting work.
+.SS Win32
+.IX Subsection "Win32"
+In multi-CPU boxes, there are some problems with the I/O buffering:
+some output may appear twice.
+.SS "XML::Parser not working"
+.IX Subsection "XML::Parser not working"
+Use XML::Parser 2.31 or later.
+.SS "z/OS (OS/390)"
+.IX Subsection "z/OS (OS/390)"
+z/OS has rather many test failures but the situation is actually much
+better than it was in 5.6.0; it's just that so many new modules and
+tests have been added.
+.PP
+.Vb 10
+\& Failed Test                   Stat Wstat Total Fail  Failed  List of Failed
+\& \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
+\& ../ext/Data/Dumper/t/dumper.t              357    8   2.24%  311 314 325 327
+\&                                                              331 333 337 339
+\& ../ext/IO/lib/IO/t/io_unix.t                 5    4  80.00%  2\-5
+\& ../ext/Storable/t/downgrade.t   12  3072   169   12   7.10%  14\-15 46\-47 78\-79
+\&                                                              110\-111 150 161
+\& ../lib/ExtUtils/t/Constant.t   121 30976    48   48 100.00%  1\-48
+\& ../lib/ExtUtils/t/Embed.t                    9    9 100.00%  1\-9
+\& op/pat.t                                   922    7   0.76%  665 776 785 832\-
+\&                                                              834 845
+\& op/sprintf.t                               224    3   1.34%  98 100 136
+\& op/tr.t                                     97    5   5.15%  63 71\-74
+\& uni/fold.t                                 780    6   0.77%  61 169 196 661
+\&                                                              710\-711
+.Ve
+.PP
+The failures in dumper.t and downgrade.t are problems in the tests,
+those in io_unix and sprintf are problems in the USS (UDP sockets and
+printf formats).  The pat, tr, and fold failures are genuine Perl
+problems caused by EBCDIC (and in the pat and fold cases, combining
+that with Unicode).  The Constant and Embed are probably problems in
+the tests (since they test Perl's ability to build extensions, and
+that seems to be working reasonably well.)
+.SS "Unicode Support on EBCDIC Still Spotty"
+.IX Subsection "Unicode Support on EBCDIC Still Spotty"
+Though mostly working, Unicode support still has problem spots on
+EBCDIC platforms.  One such known spot are the \f(CW\*(C`\ep{}\*(C'\fR and \f(CW\*(C`\eP{}\*(C'\fR
+regular expression constructs for code points less than 256: the
+\&\f(CW\*(C`pP\*(C'\fR are testing for Unicode code points, not knowing about EBCDIC.
+.SS "Seen In Perl 5.7 But Gone Now"
+.IX Subsection "Seen In Perl 5.7 But Gone Now"
+\&\f(CW\*(C`Time::Piece\*(C'\fR (previously known as \f(CW\*(C`Time::Object\*(C'\fR) was removed
+because it was felt that it didn't have enough value in it to be a
+core module.  It is still a useful module, though, and is available
+from the CPAN.
+.PP
+Perl 5.8 unfortunately does not build anymore on AmigaOS; this broke
+accidentally at some point.  Since there are not that many Amiga
+developers available, we could not get this fixed and tested in time
+for 5.8.0.  Perl 5.6.1 still works for AmigaOS (as does the 5.7.2
+development release).
+.PP
+The \f(CW\*(C`PerlIO::Scalar\*(C'\fR and \f(CW\*(C`PerlIO::Via\*(C'\fR (capitalised) were renamed as
+\&\f(CW\*(C`PerlIO::scalar\*(C'\fR and \f(CW\*(C`PerlIO::via\*(C'\fR (all lowercase) just before 5.8.0.
+The main rationale was to have all core PerlIO layers to have all
+lowercase names.  The "plugins" are named as usual, for example
+\&\f(CW\*(C`PerlIO::via::QuotedPrint\*(C'\fR.
+.PP
+The \f(CW\*(C`threads::shared::queue\*(C'\fR and \f(CW\*(C`threads::shared::semaphore\*(C'\fR were
+renamed as \f(CW\*(C`Thread::Queue\*(C'\fR and \f(CW\*(C`Thread::Semaphore\*(C'\fR just before 5.8.0.
+The main rationale was to have thread modules to obey normal naming,
+\&\f(CW\*(C`Thread::\*(C'\fR (the \f(CW\*(C`threads\*(C'\fR and \f(CW\*(C`threads::shared\*(C'\fR themselves are
+more pragma-like, they affect compile-time, so they stay lowercase).
+.SH "Reporting Bugs"
+.IX Header "Reporting Bugs"
+If you find what you think is a bug, you might check the articles
+recently posted to the comp.lang.perl.misc newsgroup and the perl
+bug database at http://bugs.perl.org/ .  There may also be
+information at http://www.perl.com/ , the Perl Home Page.
+.PP
+If you believe you have an unreported bug, please run the \fBperlbug\fR
+program included with your release.  Be sure to trim your bug down
+to a tiny but sufficient test case.  Your bug report, along with the
+output of \f(CW\*(C`perl \-V\*(C'\fR, will be sent off to perlbug@perl.org to be
+analysed by the Perl porting team.
+.SH "SEE ALSO"
+.IX Header "SEE ALSO"
+The \fIChanges\fR file for exhaustive details on what changed.
+.PP
+The \fIINSTALL\fR file for how to build Perl.
+.PP
+The \fIREADME\fR file for general stuff.
+.PP
+The \fIArtistic\fR and \fICopying\fR files for copyright information.
+.SH HISTORY
+.IX Header "HISTORY"
+Written by Jarkko Hietaniemi <\fIjhi@iki.fi\fR>.