=encoding utf8
=head1 NAME
perl5160delta - what is new for perl v5.16.0
=head1 DESCRIPTION
This document describes differences between the 5.14.0 release and
the 5.16.0 release.
If you are upgrading from an earlier release such as 5.12.0, first read
L<perl5140delta>, which describes differences between 5.12.0 and
5.14.0.
Some bug fixes in this release have been backported to later
releases of 5.14.x. Those are indicated with the 5.14.x version in
parentheses.
=head1 Notice
With the release of Perl 5.16.0, the 5.12.x series of releases is now out of
its support period. There may be future 5.12.x releases, but only in the
event of a critical security issue. Users of Perl 5.12 or earlier should
consider upgrading to a more recent release of Perl.
This policy is described in greater detail in
L<perlpolicy|perlpolicy/MAINTENANCE AND SUPPORT>.
=head1 Core Enhancements
=head2 C<use I<VERSION>>
As of this release, version declarations like C<use v5.16> now disable
all features before enabling the new feature bundle. This means that
the following holds true:
use 5.016;
# only 5.16 features enabled here
use 5.014;
# only 5.14 features enabled here (not 5.16)
C<use v5.12> and higher continue to enable strict, but explicit C<use
strict> and C<no strict> now override the version declaration, even
when they come first:
no strict;
use 5.012;
# no strict here
There is a new ":default" feature bundle that represents the set of
features enabled before any version declaration or C<use feature> has
been seen. Version declarations below 5.10 now enable the ":default"
feature set. This does not actually change the behavior of C<use
v5.8>, because features added to the ":default" set are those that were
traditionally enabled by default, before they could be turned off.
C<< no feature >> now resets to the default feature set. To disable all
features (which is likely to be a pretty special-purpose request, since
it presumably won't match any named set of semantics) you can now
write C<< no feature ':all' >>.
C<$[> is now disabled under C<use v5.16>. It is part of the default
feature set and can be turned on or off explicitly with C<use feature
'array_base'>.
=head2 C<__SUB__>
The new C<__SUB__> token, available under the C<current_sub> feature
(see L<feature>) or C<use v5.16>, returns a reference to the current
subroutine, making it easier to write recursive closures.
=head2 New and Improved Built-ins
=head3 More consistent C<eval>
The C<eval> operator sometimes treats a string argument as a sequence of
characters and sometimes as a sequence of bytes, depending on the
internal encoding. The internal encoding is not supposed to make any
difference, but there is code that relies on this inconsistency.
The new C<unicode_eval> and C<evalbytes> features (enabled under C<use
5.16.0>) resolve this. The C<unicode_eval> feature causes C<eval
$string> to treat the string always as Unicode. The C<evalbytes>
features provides a function, itself called C<evalbytes>, which
evaluates its argument always as a string of bytes.
These features also fix oddities with source filters leaking to outer
dynamic scopes.
See L<feature> for more detail.
=head3 C<substr> lvalue revamp
=for comment Does this belong here, or under Incompatible Changes?
When C<substr> is called in lvalue or potential lvalue context with two
or three arguments, a special lvalue scalar is returned that modifies
the original string (the first argument) when assigned to.
Previously, the offsets (the second and third arguments) passed to
C<substr> would be converted immediately to match the string, negative
offsets being translated to positive and offsets beyond the end of the
string being truncated.
Now, the offsets are recorded without modification in the special
lvalue scalar that is returned, and the original string is not even
looked at by C<substr> itself, but only when the returned lvalue is
read or modified.
These changes result in an incompatible change:
If the original string changes length after the call to C<substr> but
before assignment to its return value, negative offsets will remember
their position from the end of the string, affecting code like this:
my $string = "string";
my $lvalue = \substr $string, -4, 2;
print $$lvalue, "\n"; # prints "ri"
$string = "bailing twine";
print $$lvalue, "\n"; # prints "wi"; used to print "il"
The same thing happens with an omitted third argument. The returned
lvalue will always extend to the end of the string, even if the string
becomes longer.
Since this change also allowed many bugs to be fixed (see
L</The C<substr> operator>), and since the behavior
of negative offsets has never been specified, the
change was deemed acceptable.
=head3 Return value of C<tied>
The value returned by C<tied> on a tied variable is now the actual
scalar that holds the object to which the variable is tied. This
lets ties be weakened with C<Scalar::Util::weaken(tied
$tied_variable)>.
=head2 Unicode Support
=head3 Supports (I<almost>) Unicode 6.1
Besides the addition of whole new scripts, and new characters in
existing scripts, this new version of Unicode, as always, makes some
changes to existing characters. One change that may trip up some
applications is that the General Category of two characters in the
Latin-1 range, PILCROW SIGN and SECTION SIGN, has been changed from
Other_Symbol to Other_Punctuation. The same change has been made for
a character in each of Tibetan, Ethiopic, and Aegean.
The code points U+3248..U+324F (CIRCLED NUMBER TEN ON BLACK SQUARE
through CIRCLED NUMBER EIGHTY ON BLACK SQUARE) have had their General
Category changed from Other_Symbol to Other_Numeric. The Line Break
property has changes for Hebrew and Japanese; and because of
other changes in 6.1, the Perl regular expression construct C<\X> now
works differently for some characters in Thai and Lao.
New aliases (synonyms) have been defined for many property values;
these, along with the previously existing ones, are all cross-indexed in
L<perluniprops>.
The return value of C<charnames::viacode()> is affected by other
changes:
Code point Old Name New Name
U+000A LINE FEED (LF) LINE FEED
U+000C FORM FEED (FF) FORM FEED
U+000D CARRIAGE RETURN (CR) CARRIAGE RETURN
U+0085 NEXT LINE (NEL) NEXT LINE
U+008E SINGLE-SHIFT 2 SINGLE-SHIFT-2
U+008F SINGLE-SHIFT 3 SINGLE-SHIFT-3
U+0091 PRIVATE USE 1 PRIVATE USE-1
U+0092 PRIVATE USE 2 PRIVATE USE-2
U+2118 SCRIPT CAPITAL P WEIERSTRASS ELLIPTIC FUNCTION
Perl will accept any of these names as input, but
C<charnames::viacode()> now returns the new name of each pair. The
change for U+2118 is considered by Unicode to be a correction, that is
the original name was a mistake (but again, it will remain forever valid
to use it to refer to U+2118). But most of these changes are the
fallout of the mistake Unicode 6.0 made in naming a character used in
Japanese cell phones to be "BELL", which conflicts with the longstanding
industry use of (and Unicode's recommendation to use) that name
to mean the ASCII control character at U+0007. Therefore, that name
has been deprecated in Perl since v5.14, and any use of it will raise a
warning message (unless turned off). The name "ALERT" is now the
preferred name for this code point, with "BEL" an acceptable short
form. The name for the new cell phone character, at code point U+1F514,
remains undefined in this version of Perl (hence we don't
implement quite all of Unicode 6.1), but starting in v5.18, BELL will mean
this character, and not U+0007.
Unicode has taken steps to make sure that this sort of mistake does not
happen again. The Standard now includes all generally accepted
names and abbreviations for control characters, whereas previously it
didn't (though there were recommended names for most of them, which Perl
used). This means that most of those recommended names are now
officially in the Standard. Unicode did not recommend names for the
four code points listed above between U+008E and U+008F, and in
standardizing them Unicode subtly changed the names that Perl had
previously given them, by replacing the final blank in each name by a
hyphen. Unicode also officially accepts names that Perl had deprecated,
such as FILE SEPARATOR. Now the only deprecated name is BELL.
Finally, Perl now uses the new official names instead of the old
(now considered obsolete) names for the first four code points in the
list above (the ones which have the parentheses in them).
Now that the names have been placed in the Unicode standard, these kinds
of changes should not happen again, though corrections, such as to
U+2118, are still possible.
Unicode also added some name abbreviations, which Perl now accepts:
SP for SPACE;
TAB for CHARACTER TABULATION;
NEW LINE, END OF LINE, NL, and EOL for LINE FEED;
LOCKING-SHIFT ONE for SHIFT OUT;
LOCKING-SHIFT ZERO for SHIFT IN;
and ZWNBSP for ZERO WIDTH NO-BREAK SPACE.
More details on this version of Unicode are provided in
L<http://www.unicode.org/versions/Unicode6.1.0/>.
=head3 C<use charnames> is no longer needed for C<\N{I<name>}>
When C<\N{I<name>}> is encountered, the C<charnames> module is now
automatically loaded when needed as if the C<:full> and C<:short>
options had been specified. See L<charnames> for more information.
=head3 C<\N{...}> can now have Unicode loose name matching
This is described in the C<charnames> item in
L</Updated Modules and Pragmata> below.
=head3 Unicode Symbol Names
Perl now has proper support for Unicode in symbol names. It used to be
that C<*{$foo}> would ignore the internal UTF8 flag and use the bytes of
the underlying representation to look up the symbol. That meant that
C<*{"\x{100}"}> and C<*{"\xc4\x80"}> would return the same thing. All
these parts of Perl have been fixed to account for Unicode:
=over
=item *
Method names (including those passed to C<use overload>)
=item *
Typeglob names (including names of variables, subroutines, and filehandles)
=item *
Package names
=item *
C<goto>
=item *
Symbolic dereferencing
=item *
Second argument to C<bless()> and C<tie()>
=item *
Return value of C<ref()>
=item *
Subroutine prototypes
=item *
Attributes
=item *
Various warnings and error messages that mention variable names or values,
methods, etc.
=back
In addition, a parsing bug has been fixed that prevented C<*{é}> from
implicitly quoting the name, but instead interpreted it as C<*{+é}>, which
would cause a strict violation.
C<*{"*a::b"}> automatically strips off the * if it is followed by an ASCII
letter. That has been extended to all Unicode identifier characters.
One-character non-ASCII non-punctuation variables (like C<$é>) are now
subject to "Used only once" warnings. They used to be exempt, as they
were treated as punctuation variables.
Also, single-character Unicode punctuation variables (like C<$‰>) are now
supported [perl #69032].
=head3 Improved ability to mix locales and Unicode, including UTF-8 locales
An optional parameter has been added to C<use locale>
use locale ':not_characters';
which tells Perl to use all but the C<LC_CTYPE> and C<LC_COLLATE>
portions of the current locale. Instead, the character set is assumed
to be Unicode. This lets locales and Unicode be seamlessly mixed,
including the increasingly frequent UTF-8 locales. When using this
hybrid form of locales, the C<:locale> layer to the L<open> pragma can
be used to interface with the file system, and there are CPAN modules
available for ARGV and environment variable conversions.
Full details are in L<perllocale>.
=head3 New function C<fc> and corresponding escape sequence C<\F> for Unicode foldcase
Unicode foldcase is an extension to lowercase that gives better results
when comparing two strings case-insensitively. It has long been used
internally in regular expression C</i> matching. Now it is available
explicitly through the new C<fc> function call (enabled by
S<C<"use feature 'fc'">>, or C<use v5.16>, or explicitly callable via
C<CORE::fc>) or through the new C<\F> sequence in double-quotish
strings.
Full details are in L<perlfunc/fc>.
=head3 The Unicode C<Script_Extensions> property is now supported.
New in Unicode 6.0, this is an improved C<Script> property. Details
are in L<perlunicode/Scripts>.
=head2 XS Changes
=head3 Improved typemaps for Some Builtin Types
Most XS authors will know there is a longstanding bug in the
OUTPUT typemap for T_AVREF (C<AV*>), T_HVREF (C<HV*>), T_CVREF (C<CV*>),
and T_SVREF (C<SVREF> or C<\$foo>) that requires manually decrementing
the reference count of the return value instead of the typemap taking
care of this. For backwards-compatibility, this cannot be changed in the
default typemaps. But we now provide additional typemaps
C<T_AVREF_REFCOUNT_FIXED>, etc. that do not exhibit this bug. Using
them in your extension is as simple as having one line in your
C<TYPEMAP> section:
HV* T_HVREF_REFCOUNT_FIXED
=head3 C<is_utf8_char()>
The XS-callable function C<is_utf8_char()>, when presented with
malformed UTF-8 input, can read up to 12 bytes beyond the end of the
string. This cannot be fixed without changing its API, and so its
use is now deprecated. Use C<is_utf8_char_buf()> (described just below)
instead.
=head3 Added C<is_utf8_char_buf()>
This function is designed to replace the deprecated L</is_utf8_char()>
function. It includes an extra parameter to make sure it doesn't read
past the end of the input buffer.
=head3 Other C<is_utf8_foo()> functions, as well as C<utf8_to_foo()>, etc.
Most other XS-callable functions that take UTF-8 encoded input
implicitly assume that the UTF-8 is valid (not malformed) with respect to
buffer length. Do not do things such as change a character's case or
see if it is alphanumeric without first being sure that it is valid
UTF-8. This can be safely done for a whole string by using one of the
functions C<is_utf8_string()>, C<is_utf8_string_loc()>, and
C<is_utf8_string_loclen()>.
=head3 New Pad API
Many new functions have been added to the API for manipulating lexical
pads. See L<perlapi/Pad Data Structures> for more information.
=head2 Changes to Special Variables
=head3 C<$$> can be assigned to
C<$$> was made read-only in Perl 5.8.0. But only sometimes: C<local $$>
would make it writable again. Some CPAN modules were using C<local $$> or
XS code to bypass the read-only check, so there is no reason to keep C<$$>
read-only. (This change also allowed a bug to be fixed while maintaining
backward compatibility.)
=head3 C<$^X> converted to an absolute path on FreeBSD, OS X and Solaris
C<$^X> is now converted to an absolute path on OS X, FreeBSD (without
needing F</proc> mounted) and Solaris 10 and 11. This augments the
previous approach of using F</proc> on Linux, FreeBSD, and NetBSD
(in all cases, where mounted).
This makes relocatable perl installations more useful on these platforms.
(See "Relocatable @INC" in F<INSTALL>)
=head2 Debugger Changes
=head3 Features inside the debugger
The current Perl's L<feature> bundle is now enabled for commands entered
in the interactive debugger.
=head3 New option for the debugger's B<t> command
The B<t> command in the debugger, which toggles tracing mode, now
accepts a numeric argument that determines how many levels of subroutine
calls to trace.
=head3 C<enable> and C<disable>
The debugger now has C<disable> and C<enable> commands for disabling
existing breakpoints and re-enabling them. See L<perldebug>.
=head3 Breakpoints with file names
The debugger's "b" command for setting breakpoints now lets a line
number be prefixed with a file name. See
L<perldebug/"b [file]:[line] [condition]">.
=head2 The C<CORE> Namespace
=head3 The C<CORE::> prefix
The C<CORE::> prefix can now be used on keywords enabled by
L<feature.pm|feature>, even outside the scope of C<use feature>.
=head3 Subroutines in the C<CORE> namespace
Many Perl keywords are now available as subroutines in the CORE namespace.
This lets them be aliased:
BEGIN { *entangle = \&CORE::tie }
entangle $variable, $package, @args;
And for prototypes to be bypassed:
sub mytie(\[%$*@]$@) {
my ($ref, $pack, @args) = @_;
... do something ...
goto &CORE::tie;
}
Some of these cannot be called through references or via C<&foo> syntax,
but must be called as barewords.
See L<CORE> for details.
=head2 Other Changes
=head3 Anonymous handles
Automatically generated file handles are now named __ANONIO__ when the
variable name cannot be determined, rather than $__ANONIO__.
=head3 Autoloaded sort Subroutines
Custom sort subroutines can now be autoloaded [perl #30661]:
sub AUTOLOAD { ... }
@sorted = sort foo @list; # uses AUTOLOAD
=head3 C<continue> no longer requires the "switch" feature
The C<continue> keyword has two meanings. It can introduce a C<continue>
block after a loop, or it can exit the current C<when> block. Up to now,
the latter meaning was valid only with the "switch" feature enabled, and
was a syntax error otherwise. Since the main purpose of feature.pm is to
avoid conflicts with user-defined subroutines, there is no reason for
C<continue> to depend on it.
=head3 DTrace probes for interpreter phase change
The C<phase-change> probes will fire when the interpreter's phase
changes, which tracks the C<${^GLOBAL_PHASE}> variable. C<arg0> is
the new phase name; C<arg1> is the old one. This is useful
for limiting your instrumentation to one or more of: compile time,
run time, or destruct time.
=head3 C<__FILE__()> Syntax
The C<__FILE__>, C<__LINE__> and C<__PACKAGE__> tokens can now be written
with an empty pair of parentheses after them. This makes them parse the
same way as C<time>, C<fork> and other built-in functions.
=head3 The C<\$> prototype accepts any scalar lvalue
The C<\$> and C<\[$]> subroutine prototypes now accept any scalar lvalue
argument. Previously they accepted only scalars beginning with C<$> and
hash and array elements. This change makes them consistent with the way
the built-in C<read> and C<recv> functions (among others) parse their
arguments. This means that one can override the built-in functions with
custom subroutines that parse their arguments the same way.
=head3 C<_> in subroutine prototypes
The C<_> character in subroutine prototypes is now allowed before C<@> or
C<%>.
=head1 Security
=head2 Use C<is_utf8_char_buf()> and not C<is_utf8_char()>
The latter function is now deprecated because its API is insufficient to
guarantee that it doesn't read (up to 12 bytes in the worst case) beyond
the end of its input string. See
L<is_utf8_char_buf()|/Added is_utf8_char_buf()>.
=head2 Malformed UTF-8 input could cause attempts to read beyond the end of the buffer
Two new XS-accessible functions, C<utf8_to_uvchr_buf()> and
C<utf8_to_uvuni_buf()> are now available to prevent this, and the Perl
core has been converted to use them.
See L</Internal Changes>.
=head2 C<File::Glob::bsd_glob()> memory error with GLOB_ALTDIRFUNC (CVE-2011-2728).
Calling C<File::Glob::bsd_glob> with the unsupported flag
GLOB_ALTDIRFUNC would cause an access violation / segfault. A Perl
program that accepts a flags value from an external source could expose
itself to denial of service or arbitrary code execution attacks. There
are no known exploits in the wild. The problem has been corrected by
explicitly disabling all unsupported flags and setting unused function
pointers to null. Bug reported by Clément Lecigne. (5.14.2)
=head2 Privileges are now set correctly when assigning to C<$(>
A hypothetical bug (probably unexploitable in practice) because the
incorrect setting of the effective group ID while setting C<$(> has been
fixed. The bug would have affected only systems that have C<setresgid()>
but not C<setregid()>, but no such systems are known to exist.
=head1 Deprecations
=head2 Don't read the Unicode data base files in F<lib/unicore>
It is now deprecated to directly read the Unicode data base files.
These are stored in the F<lib/unicore> directory. Instead, you should
use the new functions in L<Unicode::UCD>. These provide a stable API,
and give complete information.
Perl may at some point in the future change or remove these files. The
file which applications were most likely to have used is
F<lib/unicore/ToDigit.pl>. L<Unicode::UCD/prop_invmap()> can be used to
get at its data instead.
=head2 XS functions C<is_utf8_char()>, C<utf8_to_uvchr()> and
C<utf8_to_uvuni()>
This function is deprecated because it could read beyond the end of the
input string. Use the new L<is_utf8_char_buf()|/Added is_utf8_char_buf()>,
C<utf8_to_uvchr_buf()> and C<utf8_to_uvuni_buf()> instead.
=head1 Future Deprecations
This section serves as a notice of features that are I<likely> to be
removed or L<deprecated|perlpolicy/deprecated> in the next release of
perl (5.18.0). If your code depends on these features, you should
contact the Perl 5 Porters via the L<mailing
list|http://lists.perl.org/list/perl5-porters.html> or L<perlbug> to
explain your use case and inform the deprecation process.
=head2 Core Modules
These modules may be marked as deprecated I<from the core>. This only
means that they will no longer be installed by default with the core
distribution, but will remain available on the CPAN.
=over
=item *
CPANPLUS
=item *
Filter::Simple
=item *
PerlIO::mmap
=item *
Pod::LaTeX
=item *
Pod::Parser
=item *
SelfLoader
=item *
Text::Soundex
=item *
Thread.pm
=back
=head2 Platforms with no supporting programmers
These platforms will probably have their
special build support removed during the
5.17.0 development series.
=over
=item *
BeOS
=item *
djgpp
=item *
dgux
=item *
EPOC
=item *
MPE/iX
=item *
Rhapsody
=item *
UTS
=item *
VM/ESA
=back
=head2 Other Future Deprecations
=over
=item *
Swapping of $< and $>
For more information about this future deprecation, see L<the relevant RT
ticket|https://rt.perl.org/rt3/Ticket/Display.html?id=96212>.
=item *
sfio, stdio
Perl supports being built without PerlIO proper, using a stdio or sfio
wrapper instead. A perl build like this will not support IO layers and
thus Unicode IO, making it rather handicapped.
PerlIO supports a C<stdio> layer if stdio use is desired, and similarly a
sfio layer could be produced.
=item *
Unescaped literal C<< "{" >> in regular expressions.
Starting with v5.20, it is planned to require a literal C<"{"> to be
escaped, for example by preceding it with a backslash. In v5.18, a
deprecated warning message will be emitted for all such uses.
This affects only patterns that are to match a literal C<"{">. Other
uses of this character, such as part of a quantifier or sequence as in
those below, are completely unaffected:
/foo{3,5}/
/\p{Alphabetic}/
/\N{DIGIT ZERO}
Removing this will permit extensions to Perl's pattern syntax and better
error checking for existing syntax. See L<perlre/Quantifiers> for an
example.
=item *
Revamping C<< "\Q" >> semantics in double-quotish strings when combined with other escapes.
There are several bugs and inconsistencies involving combinations
of C<\Q> and escapes like C<\x>, C<\L>, etc., within a C<\Q...\E> pair.
These need to be fixed, and doing so will necessarily change current
behavior. The changes have not yet been settled.
=back
=head1 Incompatible Changes
=head2 Special blocks called in void context
Special blocks (C<BEGIN>, C<CHECK>, C<INIT>, C<UNITCHECK>, C<END>) are now
called in void context. This avoids wasteful copying of the result of the
last statement [perl #108794].
=head2 The C<overloading> pragma and regexp objects
With C<no overloading>, regular expression objects returned by C<qr
now stringified as "Regexp=REGEXP(0xbe600d)" instead of the regular
expression itself [perl #108780].
=head2 Two XS typemap Entries removed
Two presumably unused XS typemap entries have been removed from the
core typemap: T_DATAUNIT and T_CALLBACK. If you are, against all odds,
a user of these, please see the instructions on how to restore them
in L<perlxstypemap>.
=head2 Unicode 6.1 has incompatibilities with Unicode 6.0
These are detailed in L</Supports (almost) Unicode 6.1> above.
You can compile this version of Perl to use Unicode 6.0. See
L<perlunicode/Hacking Perl to work on earlier Unicode versions (for very serious hackers only)>.
=head2 Borland compiler
All support for the Borland compiler has been dropped. The code had not
worked for a long time anyway.
=head2 Certain deprecated Unicode properties are no longer supported by default
Perl should never have exposed certain Unicode properties that are used
by Unicode internally and not meant to be publicly available. Use of
these has generated deprecated warning messages since Perl 5.12. The
removed properties are Other_Alphabetic,
Other_Default_Ignorable_Code_Point, Other_Grapheme_Extend,
Other_ID_Continue, Other_ID_Start, Other_Lowercase, Other_Math, and
Other_Uppercase.
Perl may be recompiled to include any or all of them; instructions are
given in
L<perluniprops/Unicode character properties that are NOT accepted by Perl>.
=head2 Dereferencing IO thingies as typeglobs
The C<*{...}> operator, when passed a reference to an IO thingy (as in
C<*{*STDIN{IO}}>), creates a new typeglob containing just that IO object.
Previously, it would stringify as an empty string, but some operators would
treat it as undefined, producing an "uninitialized" warning.
Now it stringifies as __ANONIO__ [perl #96326].
=head2 User-defined case-changing operations
This feature was deprecated in Perl 5.14, and has now been removed.
The CPAN module L<Unicode::Casing> provides better functionality without
the drawbacks that this feature had, as are detailed in the 5.14
documentation:
L<http://perldoc.perl.org/5.14.0/perlunicode.html#User-Defined-Case-Mappings-%28for-serious-hackers-only%29>
=head2 XSUBs are now 'static'
XSUB C functions are now 'static', that is, they are not visible from
outside the compilation unit. Users can use the new C<XS_EXTERNAL(name)>
and C<XS_INTERNAL(name)> macros to pick the desired linking behavior.
The ordinary C<XS(name)> declaration for XSUBs will continue to declare
non-'static' XSUBs for compatibility, but the XS compiler,
L<ExtUtils::ParseXS> (C<xsubpp>) will emit 'static' XSUBs by default.
L<ExtUtils::ParseXS>'s behavior can be reconfigured from XS using the
C<EXPORT_XSUB_SYMBOLS> keyword. See L<perlxs> for details.
=head2 Weakening read-only references
Weakening read-only references is no longer permitted. It should never
have worked anyway, and could sometimes result in crashes.
=head2 Tying scalars that hold typeglobs
Attempting to tie a scalar after a typeglob was assigned to it would
instead tie the handle in the typeglob's IO slot. This meant that it was
impossible to tie the scalar itself. Similar problems affected C<tied> and
C<untie>: C<tied $scalar> would return false on a tied scalar if the last
thing returned was a typeglob, and C<untie $scalar> on such a tied scalar
would do nothing.
We fixed this problem before Perl 5.14.0, but it caused problems with some
CPAN modules, so we put in a deprecation cycle instead.
Now the deprecation has been removed and this bug has been fixed. So
C<tie $scalar> will always tie the scalar, not the handle it holds. To tie
the handle, use C<tie *$scalar> (with an explicit asterisk). The same
applies to C<tied *$scalar> and C<untie *$scalar>.
=head2 IPC::Open3 no longer provides C<xfork()>, C<xclose_on_exec()>
and C<xpipe_anon()>
All three functions were private, undocumented, and unexported. They do
not appear to be used by any code on CPAN. Two have been inlined and one
deleted entirely.
=head2 C<$$> no longer caches PID
Previously, if one called fork(3) from C, Perl's
notion of C<$$> could go out of sync with what getpid() returns. By always
fetching the value of C<$$> via getpid(), this potential bug is eliminated.
Code that depends on the caching behavior will break. As described in
L<Core Enhancements|/C<$$> can be assigned to>,
C<$$> is now writable, but it will be reset during a
fork.
=head2 C<$$> and C<getppid()> no longer emulate POSIX semantics under LinuxThreads
The POSIX emulation of C<$$> and C<getppid()> under the obsolete
LinuxThreads implementation has been removed.
This only impacts users of Linux 2.4 and
users of Debian GNU/kFreeBSD up to and including 6.0, not the vast
majority of Linux installations that use NPTL threads.
This means that C<getppid()>, like C<$$>, is now always guaranteed to
return the OS's idea of the current state of the process, not perl's
cached version of it.
See the documentation for L<$$|perlvar/$$> for details.
=head2 C<< $< >>, C<< $> >>, C<$(> and C<$)> are no longer cached
Similarly to the changes to C<$$> and C<getppid()>, the internal
caching of C<< $< >>, C<< $> >>, C<$(> and C<$)> has been removed.
When we cached these values our idea of what they were would drift out
of sync with reality if someone (e.g., someone embedding perl) called
C<sete?[ug]id()> without updating C<PL_e?[ug]id>. Having to deal with
this complexity wasn't worth it given how cheap the C<gete?[ug]id()>
system call is.
This change will break a handful of CPAN modules that use the XS-level
C<PL_uid>, C<PL_gid>, C<PL_euid> or C<PL_egid> variables.
The fix for those breakages is to use C<PerlProc_gete?[ug]id()> to
retrieve them (e.g., C<PerlProc_getuid()>), and not to assign to
C<PL_e?[ug]id> if you change the UID/GID/EUID/EGID. There is no longer
any need to do so since perl will always retrieve the up-to-date
version of those values from the OS.
=head2 Which Non-ASCII characters get quoted by C<quotemeta> and C<\Q> has changed
This is unlikely to result in a real problem, as Perl does not attach
special meaning to any non-ASCII character, so it is currently
irrelevant which are quoted or not. This change fixes bug [perl #77654] and
brings Perl's behavior more into line with Unicode's recommendations.
See L<perlfunc/quotemeta>.
=head1 Performance Enhancements
=over
=item *
Improved performance for Unicode properties in regular expressions
=for comment Can this be compacted some? -- rjbs, 2012-02-20
Matching a code point against a Unicode property is now done via a
binary search instead of linear. This means for example that the worst
case for a 1000 item property is 10 probes instead of 1000. This
inefficiency has been compensated for in the past by permanently storing
in a hash the results of a given probe plus the results for the adjacent
64 code points, under the theory that near-by code points are likely to
be searched for. A separate hash was used for each mention of a Unicode
property in each regular expression. Thus, C<qr/\p{foo}abc\p{foo}/>
would generate two hashes. Any probes in one instance would be unknown
to the other, and the hashes could expand separately to be quite large
if the regular expression were used on many different widely-separated
code points.
Now, however, there is just one hash shared by all instances of a given
property. This means that if C<\p{foo}> is matched against "A" in one
regular expression in a thread, the result will be known immediately to
all regular expressions, and the relentless march of using up memory is
slowed considerably.
=item *
Version declarations with the C<use> keyword (e.g., C<use 5.012>) are now
faster, as they enable features without loading F<feature.pm>.
=item *
C<local $_> is faster now, as it no longer iterates through magic that it
is not going to copy anyway.
=item *
Perl 5.12.0 sped up the destruction of objects whose classes define
empty C<DESTROY> methods (to prevent autoloading), by simply not
calling such empty methods. This release takes this optimization a
step further, by not calling any C<DESTROY> method that begins with a
C<return> statement. This can be useful for destructors that are only
used for debugging:
use constant DEBUG => 1;
sub DESTROY { return unless DEBUG; ... }
Constant-folding will reduce the first statement to C<return;> if DEBUG
is set to 0, triggering this optimization.
=item *
Assigning to a variable that holds a typeglob or copy-on-write scalar
is now much faster. Previously the typeglob would be stringified or
the copy-on-write scalar would be copied before being clobbered.
=item *
Assignment to C<substr> in void context is now more than twice its
previous speed. Instead of creating and returning a special lvalue
scalar that is then assigned to, C<substr> modifies the original string
itself.
=item *
C<substr> no longer calculates a value to return when called in void
context.
=item *
Due to changes in L<File::Glob>, Perl's C<glob> function and its C<<
<...> >> equivalent are now much faster. The splitting of the pattern
into words has been rewritten in C, resulting in speed-ups of 20% for
some cases.
This does not affect C<glob> on VMS, as it does not use File::Glob.
=item *
The short-circuiting operators C<&&>, C<||>, and C<
(such as C<$a || $b || $c>), are now considerably faster to short-circuit,
due to reduced optree traversal.
=item *
The implementation of C<s
=item *
Recursive calls to lvalue subroutines in lvalue scalar context use less
memory.
=back
=head1 Modules and Pragmata
=head2 Deprecated Modules
=over
=item L<Version::Requirements>
Version::Requirements is now DEPRECATED, use L<CPAN::Meta::Requirements>,
which is a drop-in replacement. It will be deleted from perl.git blead
in v5.17.0.
=back
=head2 New Modules and Pragmata
=over 4
=item *
L<arybase> -- this new module implements the C<$[> variable.
=item *
L<PerlIO::mmap> 0.010 has been added to the Perl core.
The C<mmap> PerlIO layer is no longer implemented by perl itself, but has
been moved out into the new L<PerlIO::mmap> module.
=back
=head2 Updated Modules and Pragmata
This is only an overview of selected module updates. For a complete list of
updates, run:
$ corelist --diff 5.14.0 5.16.0
You can substitute your favorite version in place of 5.14.0, too.
=over 4
=item *
L<Archive::Extract> has been upgraded from version 0.48 to 0.58.
Includes a fix for FreeBSD to only use C<unzip> if it is located in
C</usr/local/bin>, as FreeBSD 9.0 will ship with a limited C<unzip> in
C</usr/bin>.
=item *
L<Archive::Tar> has been upgraded from version 1.76 to 1.82.
Adjustments to handle files >8gb (>0777777777777 octal) and a feature
to return the MD5SUM of files in the archive.
=item *
L<base> has been upgraded from version 2.16 to 2.18.
C<base> no longer sets a module's C<$VERSION> to "-1" when a module it
loads does not define a C<$VERSION>. This change has been made because
"-1" is not a valid version number under the new "lax" criteria used
internally by C<UNIVERSAL::VERSION>. (See L<version> for more on "lax"
version criteria.)
C<base> no longer internally skips loading modules it has already loaded
and instead relies on C<require> to inspect C<%INC>. This fixes a bug
when C<base> is used with code that clear C<%INC> to force a module to
be reloaded.
=item *
L<Carp> has been upgraded from version 1.20 to 1.26.
It now includes last read filehandle info and puts a dot after the file
and line number, just like errors from C<die> [perl #106538].
=item *
L<charnames> has been updated from version 1.18 to 1.30.
C<charnames> can now be invoked with a new option, C<:loose>,
which is like the existing C<:full> option, but enables Unicode loose
name matching. Details are in L<charnames/LOOSE MATCHES>.
=item *
L<B::Deparse> has been upgraded from version 1.03 to 1.14. This fixes
numerous deparsing bugs.
=item *
L<CGI> has been upgraded from version 3.52 to 3.59.
It uses the public and documented FCGI.pm API in CGI::Fast. CGI::Fast was
using an FCGI API that was deprecated and removed from documentation
more than ten years ago. Usage of this deprecated API with FCGI E<gt>=
0.70 or FCGI E<lt>= 0.73 introduces a security issue.
L<https://rt.cpan.org/Public/Bug/Display.html?id=68380>
L<http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2011-2766>
Things that may break your code:
C<url()> was fixed to return C<PATH_INFO> when it is explicitly requested
with either the C<path=E<gt>1> or C<path_info=E<gt>1> flag.
If your code is running under mod_rewrite (or compatible) and you are
calling C<self_url()> or you are calling C<url()> and passing
C<path_info=E<gt>1>, these methods will actually be returning
C<PATH_INFO> now, as you have explicitly requested or C<self_url()>
has requested on your behalf.
The C<PATH_INFO> has been omitted in such URLs since the issue was
introduced in the 3.12 release in December, 2005.
This bug is so old your application may have come to depend on it or
workaround it. Check for application before upgrading to this release.
Examples of affected method calls:
$q->url(-absolute => 1, -query => 1, -path_info => 1);
$q->url(-path=>1);
$q->url(-full=>1,-path=>1);
$q->url(-rewrite=>1,-path=>1);
$q->self_url();
We no longer read from STDIN when the Content-Length is not set,
preventing requests with no Content-Length from sometimes freezing.
This is consistent with the CGI RFC 3875, and is also consistent with
CGI::Simple. However, the old behavior may have been expected by some
command-line uses of CGI.pm.
In addition, the DELETE HTTP verb is now supported.
=item *
L<Compress::Zlib> has been upgraded from version 2.035 to 2.048.
IO::Compress::Zip and IO::Uncompress::Unzip now have support for LZMA
(method 14). There is a fix for a CRC issue in IO::Compress::Unzip and
it supports Streamed Stored context now. And fixed a Zip64 issue in
IO::Compress::Zip when the content size was exactly 0xFFFFFFFF.
=item *
L<Digest::SHA> has been upgraded from version 5.61 to 5.71.
Added BITS mode to the addfile method and shasum. This makes
partial-byte inputs possible via files/STDIN and lets shasum check
all 8074 NIST Msg vectors, where previously special programming was
required to do this.
=item *
L<Encode> has been upgraded from version 2.42 to 2.44.
Missing aliases added, a deep recursion error fixed and various
documentation updates.
Addressed 'decode_xs n-byte heap-overflow' security bug in Unicode.xs
(CVE-2011-2939). (5.14.2)
=item *
L<ExtUtils::CBuilder> updated from version 0.280203 to 0.280206.
The new version appends CFLAGS and LDFLAGS to their Config.pm
counterparts.
=item *
L<ExtUtils::ParseXS> has been upgraded from version 2.2210 to 3.16.
Much of L<ExtUtils::ParseXS>, the module behind the XS compiler C<xsubpp>,
was rewritten and cleaned up. It has been made somewhat more extensible
and now finally uses strictures.
The typemap logic has been moved into a separate module,
L<ExtUtils::Typemaps>. See L</New Modules and Pragmata>, above.
For a complete set of changes, please see the ExtUtils::ParseXS
changelog, available on the CPAN.
=item *
L<File::Glob> has been upgraded from version 1.12 to 1.17.
On Windows, tilde (~) expansion now checks the C<USERPROFILE> environment
variable, after checking C<HOME>.
It has a new C<:bsd_glob> export tag, intended to replace C<:glob>. Like
C<:glob> it overrides C<glob> with a function that does not split the glob
pattern into words, but, unlike C<:glob>, it iterates properly in scalar
context, instead of returning the last file.
There are other changes affecting Perl's own C<glob> operator (which uses
File::Glob internally, except on VMS). See L</Performance Enhancements>
and L</Selected Bug Fixes>.
=item *
L<FindBin> updated from version 1.50 to 1.51.
It no longer returns a wrong result if a script of the same name as the
current one exists in the path and is executable.
=item *
L<HTTP::Tiny> has been upgraded from version 0.012 to 0.017.
Added support for using C<$ENV{http_proxy}> to set the default proxy host.
Adds additional shorthand methods for all common HTTP verbs,
a C<post_form()> method for POST-ing x-www-form-urlencoded data and
a C<www_form_urlencode()> utility method.
=item *
L<IO> has been upgraded from version 1.25_04 to 1.25_06, and L<IO::Handle>
from version 1.31 to 1.33.
Together, these upgrades fix a problem with IO::Handle's C<getline> and
C<getlines> methods. When these methods are called on the special ARGV
handle, the next file is automatically opened, as happens with the built-in
C<E<lt>E<gt>> and C<readline> functions. But, unlike the built-ins, these
methods were not respecting the caller's use of the L<open> pragma and
applying the appropriate I/O layers to the newly-opened file
[rt.cpan.org #66474].
=item *
L<IPC::Cmd> has been upgraded from version 0.70 to 0.76.
Capturing of command output (both C<STDOUT> and C<STDERR>) is now supported
using L<IPC::Open3> on MSWin32 without requiring L<IPC::Run>.
=item *
L<IPC::Open3> has been upgraded from version 1.09 to 1.12.
Fixes a bug which prevented use of C<open3> on Windows when C<*STDIN>,
C<*STDOUT> or C<*STDERR> had been localized.
Fixes a bug which prevented duplicating numeric file descriptors on Windows.
C<open3> with "-" for the program name works once more. This was broken in
version 1.06 (and hence in Perl 5.14.0) [perl #95748].
=item *
L<Locale::Codes> has been upgraded from version 3.16 to 3.21.
Added Language Extension codes (langext) and Language Variation codes (langvar)
as defined in the IANA language registry.
Added language codes from ISO 639-5
Added language/script codes from the IANA language subtag registry
Fixed an uninitialized value warning [rt.cpan.org #67438].
Fixed the return value for the all_XXX_codes and all_XXX_names functions
[rt.cpan.org #69100].
Reorganized modules to move Locale::MODULE to Locale::Codes::MODULE to allow
for cleaner future additions. The original four modules (Locale::Language,
Locale::Currency, Locale::Country, Locale::Script) will continue to work, but
all new sets of codes will be added in the Locale::Codes namespace.
The code2XXX, XXX2code, all_XXX_codes, and all_XXX_names functions now
support retired codes. All codesets may be specified by a constant or
by their name now. Previously, they were specified only by a constant.
The alias_code function exists for backward compatibility. It has been
replaced by rename_country_code. The alias_code function will be
removed some time after September, 2013.
All work is now done in the central module (Locale::Codes). Previously,
some was still done in the wrapper modules (Locale::Codes::*). Added
Language Family codes (langfam) as defined in ISO 639-5.
=item *
L<Math::BigFloat> has been upgraded from version 1.993 to 1.997.
The C<numify> method has been corrected to return a normalized Perl number
(the result of C<0 + $thing>), instead of a string [rt.cpan.org #66732].
=item *
L<Math::BigInt> has been upgraded from version 1.994 to 1.998.
It provides a new C<bsgn> method that complements the C<babs> method.
It fixes the internal C<objectify> function's handling of "foreign objects"
so they are converted to the appropriate class (Math::BigInt or
Math::BigFloat).
=item *
L<Math::BigRat> has been upgraded from version 0.2602 to 0.2603.
C<int()> on a Math::BigRat object containing -1/2 now creates a
Math::BigInt containing 0, rather than -0. L<Math::BigInt> does not even
support negative zero, so the resulting object was actually malformed
[perl #95530].
=item *
L<Math::Complex> has been upgraded from version 1.56 to 1.59
and L<Math::Trig> from version 1.2 to 1.22.
Fixes include: correct copy constructor usage; fix polarwise formatting with
numeric format specifier; and more stable C<great_circle_direction> algorithm.
=item *
L<Module::CoreList> has been upgraded from version 2.51 to 2.66.
The C<corelist> utility now understands the C<-r> option for displaying
Perl release dates and the C<--diff> option to print the set of modlib
changes between two perl distributions.
=item *
L<Module::Metadata> has been upgraded from version 1.000004 to 1.000009.
Adds C<provides> method to generate a CPAN META provides data structure
correctly; use of C<package_versions_from_directory> is discouraged.
=item *
L<ODBM_File> has been upgraded from version 1.10 to 1.12.
The XS code is now compiled with C<PERL_NO_GET_CONTEXT>, which will aid
performance under ithreads.
=item *
L<open> has been upgraded from version 1.08 to 1.10.
It no longer turns off layers on standard handles when invoked without the
":std" directive. Similarly, when invoked I<with> the ":std" directive, it
now clears layers on STDERR before applying the new ones, and not just on
STDIN and STDOUT [perl #92728].
=item *
L<overload> has been upgraded from version 1.13 to 1.18.
C<overload::Overloaded> no longer calls C<can> on the class, but uses
another means to determine whether the object has overloading. It was
never correct for it to call C<can>, as overloading does not respect
AUTOLOAD. So classes that autoload methods and implement C<can> no longer
have to account for overloading [perl #40333].
A warning is now produced for invalid arguments. See L</New Diagnostics>.
=item *
L<PerlIO::scalar> has been upgraded from version 0.11 to 0.14.
(This is the module that implements C<< open $fh, '>', \$scalar >>.)
It fixes a problem with C<< open my $fh, ">", \$scalar >> not working if
C<$scalar> is a copy-on-write scalar. (5.14.2)
It also fixes a hang that occurs with C<readline> or C<< <$fh> >> if a
typeglob has been assigned to $scalar [perl #92258].
It no longer assumes during C<seek> that $scalar is a string internally.
If it didn't crash, it was close to doing so [perl #92706]. Also, the
internal print routine no longer assumes that the position set by C<seek>
is valid, but extends the string to that position, filling the intervening
bytes (between the old length and the seek position) with nulls
[perl #78980].
Printing to an in-memory handle now works if the $scalar holds a reference,
stringifying the reference before modifying it. References used to be
treated as empty strings.
Printing to an in-memory handle no longer crashes if the $scalar happens to
hold a number internally, but no string buffer.
Printing to an in-memory handle no longer creates scalars that confuse
the regular expression engine [perl #108398].
=item *
L<Pod::Functions> has been upgraded from version 1.04 to 1.05.
F<Functions.pm> is now generated at perl build time from annotations in
F<perlfunc.pod>. This will ensure that L<Pod::Functions> and L<perlfunc>
remain in synchronisation.
=item *
L<Pod::Html> has been upgraded from version 1.11 to 1.1502.
This is an extensive rewrite of Pod::Html to use L<Pod::Simple> under
the hood. The output has changed significantly.
=item *
L<Pod::Perldoc> has been upgraded from version 3.15_03 to 3.17.
It corrects the search paths on VMS [perl #90640]. (5.14.1)
The B<-v> option now fetches the right section for C<$0>.
This upgrade has numerous significant fixes. Consult its changelog on
the CPAN for more information.
=item *
L<POSIX> has been upgraded from version 1.24 to 1.30.
L<POSIX> no longer uses L<AutoLoader>. Any code which was relying on this
implementation detail was buggy, and may fail because of this change.
The module's Perl code has been considerably simplified, roughly halving
the number of lines, with no change in functionality. The XS code has
been refactored to reduce the size of the shared object by about 12%,
with no change in functionality. More POSIX functions now have tests.
C<sigsuspend> and C<pause> now run signal handlers before returning, as the
whole point of these two functions is to wait until a signal has
arrived, and then return I<after> it has been triggered. Delayed, or
"safe", signals were preventing that from happening, possibly resulting in
race conditions [perl #107216].
C<POSIX::sleep> is now a direct call into the underlying OS C<sleep>
function, instead of being a Perl wrapper on C<CORE::sleep>.
C<POSIX::dup2> now returns the correct value on Win32 (I<i.e.>, the file
descriptor). C<POSIX::SigSet> C<sigsuspend> and C<sigpending> and
C<POSIX::pause> now dispatch safe signals immediately before returning to
their caller.
C<POSIX::Termios::setattr> now defaults the third argument to C<TCSANOW>,
instead of 0. On most platforms C<TCSANOW> is defined to be 0, but on some
0 is not a valid parameter, which caused a call with defaults to fail.
=item *
L<Socket> has been upgraded from version 1.94 to 2.001.
It has new functions and constants for handling IPv6 sockets:
pack_ipv6_mreq
unpack_ipv6_mreq
IPV6_ADD_MEMBERSHIP
IPV6_DROP_MEMBERSHIP
IPV6_MTU
IPV6_MTU_DISCOVER
IPV6_MULTICAST_HOPS
IPV6_MULTICAST_IF
IPV6_MULTICAST_LOOP
IPV6_UNICAST_HOPS
IPV6_V6ONLY
=item *
L<Storable> has been upgraded from version 2.27 to 2.34.
It no longer turns copy-on-write scalars into read-only scalars when
freezing and thawing.
=item *
L<Sys::Syslog> has been upgraded from version 0.27 to 0.29.
This upgrade closes many outstanding bugs.
=item *
L<Term::ANSIColor> has been upgraded from version 3.00 to 3.01.
Only interpret an initial array reference as a list of colors, not any initial
reference, allowing the colored function to work properly on objects with
stringification defined.
=item *
L<Term::ReadLine> has been upgraded from version 1.07 to 1.09.
Term::ReadLine now supports any event loop, including unpublished ones and
simple L<IO::Select>, loops without the need to rewrite existing code for
any particular framework [perl #108470].
=item *
L<threads::shared> has been upgraded from version 1.37 to 1.40.
Destructors on shared objects used to be ignored sometimes if the objects
were referenced only by shared data structures. This has been mostly
fixed, but destructors may still be ignored if the objects still exist at
global destruction time [perl #98204].
=item *
L<Unicode::Collate> has been upgraded from version 0.73 to 0.89.
Updated to CLDR 1.9.1
Locales updated to CLDR 2.0: mk, mt, nb, nn, ro, ru, sk, sr, sv, uk,
zh__pinyin, zh__stroke
Newly supported locales: bn, fa, ml, mr, or, pa, sa, si, si__dictionary,
sr_Latn, sv__reformed, ta, te, th, ur, wae.
Tailored compatibility ideographs as well as unified ideographs for the
locales: ja, ko, zh__big5han, zh__gb2312han, zh__pinyin, zh__stroke.
Localeg> would sometimes refuse to match at the end of a string that ends
with "\n". This has been fixed [perl #109206].
=item *
Starting with 5.12.0, Perl used to get its internal bookkeeping muddled up
after assigning C<${ qr
L<Hash::Util>. This could result in double frees, crashes, or erratic
behavior.
=item *
The new (in 5.14.0) regular expression modifier C</a> when repeated like
C</aa> forbids the characters outside the ASCII range that match
characters inside that range from matching under C</i>. This did not
work under some circumstances, all involving alternation, such as:
"\N{KELVIN SIGN}" =~ /k|foo/iaa;
succeeded inappropriately. This is now fixed.
=item *
5.14.0 introduced some memory leaks in regular expression character
classes such as C<[\w\s]>, which have now been fixed. (5.14.1)
=item *
An edge case in regular expression matching could potentially loop.
This happened only under C</i> in bracketed character classes that have
characters with multi-character folds, and the target string to match
against includes the first portion of the fold, followed by another
character that has a multi-character fold that begins with the remaining
portion of the fold, plus some more.
"s\N{U+DF}" =~ /[\x{DF}foo]/i
is one such case. C<\xDF> folds to C<"ss">. (5.14.1)
=item *
A few characters in regular expression pattern matches did not
match correctly in some circumstances, all involving C</i>. The
affected characters are:
COMBINING GREEK YPOGEGRAMMENI,
GREEK CAPITAL LETTER IOTA,
GREEK CAPITAL LETTER UPSILON,
GREEK PROSGEGRAMMENI,
GREEK SMALL LETTER IOTA WITH DIALYTIKA AND OXIA,
GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS,
GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND OXIA,
GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS,
LATIN SMALL LETTER LONG S,
LATIN SMALL LIGATURE LONG S T,
and
LATIN SMALL LIGATURE ST.
=item *
A memory leak regression in regular expression compilation
under threading has been fixed.
=item *
A regression introduced in 5.14.0 has
been fixed. This involved an inverted
bracketed character class in a regular expression that consisted solely
of a Unicode property. That property wasn't getting inverted outside the
Latin1 range.
=item *
Three problematic Unicode characters now work better in regex pattern matching under C</i>.
In the past, three Unicode characters:
LATIN SMALL LETTER SHARP S,
GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS,
and
GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS,
along with the sequences that they fold to
(including "ss" for LATIN SMALL LETTER SHARP S),
did not properly match under C</i>. 5.14.0 fixed some of these cases,
but introduced others, including a panic when one of the characters or
sequences was used in the C<(?(DEFINE)> regular expression predicate.
The known bugs that were introduced in 5.14 have now been fixed; as well
as some other edge cases that have never worked until now. These all
involve using the characters and sequences outside bracketed character
classes under C</i>. This closes [perl #98546].
There remain known problems when using certain characters with
multi-character folds inside bracketed character classes, including such
constructs as C<qr/[\N{LATIN SMALL LETTER SHARP}a-z]/i>. These
remaining bugs are addressed in [perl #89774].
=item *
RT #78266: The regex engine has been leaking memory when accessing
named captures that weren't matched as part of a regex ever since 5.10
when they were introduced; e.g., this would consume over a hundred MB of
memory:
for (1..10_000_000) {
if ("foo" =~ /(foo|(?<capture>bar))?/) {
my $capture = $+{capture}
}
}
system "ps -o rss $$"'
=item *
In 5.14, C</[[:lower:]]/i> and C</[[:upper:]]/i> no longer matched the
opposite case. This has been fixed [perl #101970].
=item *
A regular expression match with an overloaded object on the right-hand side
would sometimes stringify the object too many times.
=item *
A regression has been fixed that was introduced in 5.14, in C</i>
regular expression matching, in which a match improperly fails if the
pattern is in UTF-8, the target string is not, and a Latin-1 character
precedes a character in the string that should match the pattern.
[perl #101710]
=item *
In case-insensitive regular expression pattern matching, no longer on
UTF-8 encoded strings does the scan for the start of match look only at
the first possible position. This caused matches such as
C<"f\x{FB00}" =~ /ff/i> to fail.
=item *
The regexp optimizer no longer crashes on debugging builds when merging
fixed-string nodes with inconvenient contents.
=item *
A panic involving the combination of the regular expression modifiers
C</aa> and the C<\b> escape sequence introduced in 5.14.0 has been
fixed [perl #95964]. (5.14.2)
=item *
The combination of the regular expression modifiers C</aa> and the C<\b>
and C<\B> escape sequences did not work properly on UTF-8 encoded
strings. All non-ASCII characters under C</aa> should be treated as
non-word characters, but what was happening was that Unicode rules were
used to determine wordness/non-wordness for non-ASCII characters. This
is now fixed [perl #95968].
=item *
C<< (?foo: ...) >> no longer loses passed in character set.
=item *
The trie optimization used to have problems with alternations containing
an empty C<(?:)>, causing C<< "x" =~ /\A(?>(?:(?:)A|B|C?x))\z/ >> not to
match, whereas it should [perl #111842].
=item *
Use of lexical (C<my>) variables in code blocks embedded in regular
expressions will no longer result in memory corruption or crashes.
Nevertheless, these code blocks are still experimental, as there are still
problems with the wrong variables being closed over (in loops for instance)
and with abnormal exiting (e.g., C<die>) causing memory corruption.
=item *
The C<\h>, C<\H>, C<\v> and C<\V> regular expression metacharacters used to
cause a panic error message when trying to match at the end of the
string [perl #96354].
=item *
The abbreviations for four C1 control characters C<MW> C<PM>, C<RI>, and
C<ST> were previously unrecognized by C<\N{}>, vianame(), and
string_vianame().
=item *
Mentioning a variable named "&" other than C<$&> (i.e., C<@&> or C<%&>) no
longer stops C<$&> from working. The same applies to variables named "'"
and "`" [perl #24237].
=item *
Creating a C<UNIVERSAL::AUTOLOAD> sub no longer stops C<%+>, C<%-> and
C<%!> from working some of the time [perl #105024].
=back
=head2 Smartmatching
=over
=item *
C<~~> now correctly handles the precedence of Any~~Object, and is not tricked
by an overloaded object on the left-hand side.
=item *
In Perl 5.14.0, C<$tainted ~~ @array> stopped working properly. Sometimes
it would erroneously fail (when C<$tainted> contained a string that occurs
in the array I<after> the first element) or erroneously succeed (when
C<undef> occurred after the first element) [perl #93590].
=back
=head2 The C<sort> operator
=over
=item *
C<sort> was not treating C<sub {}> and C<sub {()}> as equivalent when
such a sub was provided as the comparison routine. It used to croak on
C<sub {()}>.
=item *
C<sort> now works once more with custom sort routines that are XSUBs. It
stopped working in 5.10.0.
=item *
C<sort> with a constant for a custom sort routine, although it produces
unsorted results, no longer crashes. It started crashing in 5.10.0.
=item *
Warnings emitted by C<sort> when a custom comparison routine returns a
non-numeric value now contain "in sort" and show the line number of the
C<sort> operator, rather than the last line of the comparison routine. The
warnings also now occur only if warnings are enabled in the scope where
C<sort> occurs. Previously the warnings would occur if enabled in the
comparison routine's scope.
=item *
C<< sort { $a <=> $b } >>, which is optimized internally, now produces
"uninitialized" warnings for NaNs (not-a-number values), since C<< <=> >>
returns C<undef> for those. This brings it in line with
S<C<< sort { 1; $a <=> $b } >>> and other more complex cases, which are not
optimized [perl #94390].
=back
=head2 The C<substr> operator
=over
=item *
Tied (and otherwise magical) variables are no longer exempt from the
"Attempt to use reference as lvalue in substr" warning.
=item *
That warning now occurs when the returned lvalue is assigned to, not
when C<substr> itself is called. This makes a difference only if the
return value of C<substr> is referenced and later assigned to.
=item *
Passing a substring of a read-only value or a typeglob to a function
(potential lvalue context) no longer causes an immediate "Can't coerce"
or "Modification of a read-only value" error. That error occurs only
if the passed value is assigned to.
The same thing happens with the "substr outside of string" error. If
the lvalue is only read from, not written to, it is now just a warning, as
with rvalue C<substr>.
=item *
C<substr> assignments no longer call FETCH twice if the first argument
is a tied variable, just once.
=back
=head2 Support for embedded nulls
Some parts of Perl did not work correctly with nulls (C<chr 0>) embedded in
strings. That meant that, for instance, C<< $m = "a\0b"; foo->$m >> would
call the "a" method, instead of the actual method name contained in $m.
These parts of perl have been fixed to support nulls:
=over
=item *
Method names
=item *
Typeglob names (including filehandle and subroutine names)
=item *
Package names, including the return value of C<ref()>
=item *
Typeglob elements (C<*foo{"THING\0stuff"}>)
=item *
Signal names
=item *
Various warnings and error messages that mention variable names or values,
methods, etc.
=back
One side effect of these changes is that blessing into "\0" no longer
causes C<ref()> to return false.
=head2 Threading bugs
=over
=item *
Typeglobs returned from threads are no longer cloned if the parent thread
already has a glob with the same name. This means that returned
subroutines will now assign to the right package variables [perl #107366].
=item *
Some cases of threads crashing due to memory allocation during cloning have
been fixed [perl #90006].
=item *
Thread joining would sometimes emit "Attempt to free unreferenced scalar"
warnings if C<caller> had been used from the C<DB> package before thread
creation [perl #98092].
=item *
Locking a subroutine (via C<lock &sub>) is no longer a compile-time error
for regular subs. For lvalue subroutines, it no longer tries to return the
sub as a scalar, resulting in strange side effects like C<ref \$_>
returning "CODE" in some instances.
C<lock &sub> is now a run-time error if L<threads::shared> is loaded (a
no-op otherwise), but that may be rectified in a future version.
=back
=head2 Tied variables
=over
=item *
Various cases in which FETCH was being ignored or called too many times
have been fixed:
=over
=item *
C<PerlIO::get_layers> [perl #97956]
=item *
C<$tied =~ y/a/b/>, C<chop $tied> and C<chomp $tied> when $tied holds a
reference.
=item *
When calling C<local $_> [perl #105912]
=item *
Four-argument C<select>
=item *
A tied buffer passed to C<sysread>
=item *
C<< $tied .= <> >>
=item *
Three-argument C<open>, the third being a tied file handle
(as in C<< open $fh, ">&", $tied >>)
=item *
C<sort> with a reference to a tied glob for the comparison routine.
=item *
C<..> and C<...> in list context [perl #53554].
=item *
C<${$tied}>, C<@{$tied}>, C<%{$tied}> and C<*{$tied}> where the tied
variable returns a string (C<&{}> was unaffected)
=item *
C<defined ${ $tied_variable }>
=item *
Various functions that take a filehandle argument in rvalue context
(C<close>, C<readline>, etc.) [perl #97482]
=item *
Some cases of dereferencing a complex expression, such as
C<${ (), $tied } = 1>, used to call C<FETCH> multiple times, but now call
it once.
=item *
C<$tied-E<gt>method> where $tied returns a package name--even resulting in
a failure to call the method, due to memory corruption
=item *
Assignments like C<*$tied = \&{"..."}> and C<*glob = $tied>
=item *
C<chdir>, C<chmod>, C<chown>, C<utime>, C<truncate>, C<stat>, C<lstat> and
the filetest ops (C<-r>, C<-x>, etc.)
=back
=item *
C<caller> sets C<@DB::args> to the subroutine arguments when called from
the DB package. It used to crash when doing so if C<@DB::args> happened to
be tied. Now it croaks instead.
=item *
Tying an element of %ENV or C<%^H> and then deleting that element would
result in a call to the tie object's DELETE method, even though tying the
element itself is supposed to be equivalent to tying a scalar (the element
is, of course, a scalar) [perl #67490].
=item *
When Perl autovivifies an element of a tied array or hash (which entails
calling STORE with a new reference), it now calls FETCH immediately after
the STORE, instead of assuming that FETCH would have returned the same
reference. This can make it easier to implement tied objects [perl #35865, #43011].
=item *
Four-argument C<select> no longer produces its "Non-string passed as
bitmask" warning on tied or tainted variables that are strings.
=item *
Localizing a tied scalar that returns a typeglob no longer stops it from
being tied till the end of the scope.
=item *
Attempting to C<goto> out of a tied handle method used to cause memory
corruption or crashes. Now it produces an error message instead
[perl #8611].
=item *
A bug has been fixed that occurs when a tied variable is used as a
subroutine reference: if the last thing assigned to or returned from the
variable was a reference or typeglob, the C<\&$tied> could either crash or
return the wrong subroutine. The reference case is a regression introduced
in Perl 5.10.0. For typeglobs, it has probably never worked till now.
=back
=head2 Version objects and vstrings
=over
=item *
The bitwise complement operator (and possibly other operators, too) when
passed a vstring would leave vstring magic attached to the return value,
even though the string had changed. This meant that
C<< version->new(~v1.2.3) >> would create a version looking like "v1.2.3"
even though the string passed to C<< version->new >> was actually
"\376\375\374". This also caused L<B::Deparse> to deparse C<~v1.2.3>
incorrectly, without the C<~> [perl #29070].
=item *
Assigning a vstring to a magic (e.g., tied, C<$!>) variable and then
assigning something else used to blow away all magic. This meant that
tied variables would come undone, C<$!> would stop getting updated on
failed system calls, C<$|> would stop setting autoflush, and other
mischief would take place. This has been fixed.
=item *
C<< version->new("version") >> and C<printf "%vd", "version"> no longer
crash [perl #102586].
=item *
Version comparisons, such as those that happen implicitly with C<use
v5.43>, no longer cause locale settings to change [perl #105784].
=item *
Version objects no longer cause memory leaks in boolean context
[perl #109762].
=back
=head2 Warnings, redefinition
=over
=item *
Subroutines from the C<autouse> namespace are once more exempt from
redefinition warnings. This used to work in 5.005, but was broken in
5.6 for most subroutines. For subs created via XS that redefine
subroutines from the C<autouse> package, this stopped working in 5.10.
=item *
New XSUBs now produce redefinition warnings if they overwrite existing
subs, as they did in 5.8.x. (The C<autouse> logic was reversed in
5.10-14. Only subroutines from the C<autouse> namespace would warn
when clobbered.)
=item *
C<newCONSTSUB> used to use compile-time warning hints, instead of
run-time hints. The following code should never produce a redefinition
warning, but it used to, if C<newCONSTSUB> redefined an existing
subroutine:
use warnings;
BEGIN {
no warnings;
some_XS_function_that_calls_new_CONSTSUB();
}
=item *
Redefinition warnings for constant subroutines are on by default (what
are known as severe warnings in L<perldiag>). This occurred only
when it was a glob assignment or declaration of a Perl subroutine that
caused the warning. If the creation of XSUBs triggered the warning, it
was not a default warning. This has been corrected.
=item *
The internal check to see whether a redefinition warning should occur
used to emit "uninitialized" warnings in cases like this:
use warnings "uninitialized";
use constant {u => undef, v => undef};
sub foo(){u}
sub foo(){v}
=back
=head2 Warnings, "Uninitialized"
=over
=item *
Various functions that take a filehandle argument in rvalue context
(C<close>, C<readline>, etc.) used to warn twice for an undefined handle
[perl #97482].
=item *
C<dbmopen> now only warns once, rather than three times, if the mode
argument is C<undef> [perl #90064].
=item *
The C<+=> operator does not usually warn when the left-hand side is
C<undef>, but it was doing so for tied variables. This has been fixed
[perl #44895].
=item *
A bug fix in Perl 5.14 introduced a new bug, causing "uninitialized"
warnings to report the wrong variable if the operator in question had
two operands and one was C<%{...}> or C<@{...}>. This has been fixed
[perl #103766].
=item *
C<..> and C<...> in list context now mention the name of the variable in
"uninitialized" warnings for string (as opposed to numeric) ranges.
=back
=head2 Weak references
=over
=item *
Weakening the first argument to an automatically-invoked C<DESTROY> method
could result in erroneous "DESTROY created new reference" errors or
crashes. Now it is an error to weaken a read-only reference.
=item *
Weak references to lexical hashes going out of scope were not going stale
(becoming undefined), but continued to point to the hash.
=item *
Weak references to lexical variables going out of scope are now broken
before any magical methods (e.g., DESTROY on a tie object) are called.
This prevents such methods from modifying the variable that will be seen
the next time the scope is entered.
=item *
Creating a weak reference to an @ISA array or accessing the array index
(C<$#ISA>) could result in confused internal bookkeeping for elements
later added to the @ISA array. For instance, creating a weak
reference to the element itself could push that weak reference on to @ISA;
and elements added after use of C<$#ISA> would be ignored by method lookup
[perl #85670].
=back
=head2 Other notable fixes
=over
=item *
C<quotemeta> now quotes consistently the same non-ASCII characters under
C<use feature 'unicode_strings'>, regardless of whether the string is
encoded in UTF-8 or not, hence fixing the last vestiges (we hope) of the
notorious L<perlunicode/The "Unicode Bug">. [perl #77654].
Which of these code points is quoted has changed, based on Unicode's
recommendations. See L<perlfunc/quotemeta> for details.
=item *
C<study> is now a no-op, presumably fixing all outstanding bugs related to
study causing regex matches to behave incorrectly!
=item *
When one writes C<open foo || die>, which used to work in Perl 4, a
"Precedence problem" warning is produced. This warning used erroneously to
apply to fully-qualified bareword handle names not followed by C<||>. This
has been corrected.
=item *
After package aliasing (C<*foo:: = *bar::>), C<select> with 0 or 1 argument
would sometimes return a name that could not be used to refer to the
filehandle, or sometimes it would return C<undef> even when a filehandle
was selected. Now it returns a typeglob reference in such cases.
=item *
C<PerlIO::get_layers> no longer ignores some arguments that it thinks are
numeric, while treating others as filehandle names. It is now consistent
for flat scalars (i.e., not references).
=item *
Unrecognized switches on C<#!> line
If a switch, such as B<-x>, that cannot occur on the C<#!> line is used
there, perl dies with "Can't emulate...".
It used to produce the same message for switches that perl did not
recognize at all, whether on the command line or the C<#!> line.
Now it produces the "Unrecognized switch" error message [perl #104288].
=item *
C<system> now temporarily blocks the SIGCHLD signal handler, to prevent the
signal handler from stealing the exit status [perl #105700].
=item *
The %n formatting code for C<printf> and C<sprintf>, which causes the number
of characters to be assigned to the next argument, now actually
assigns the number of characters, instead of the number of bytes.
It also works now with special lvalue functions like C<substr> and with
nonexistent hash and array elements [perl #3471, #103492].
=item *
Perl skips copying values returned from a subroutine, for the sake of
speed, if doing so would make no observable difference. Because of faulty
logic, this would happen with the
result of C<delete>, C<shift> or C<splice>, even if the result was
referenced elsewhere. It also did so with tied variables about to be freed
[perl #91844, #95548].
=item *
C<utf8::decode> now refuses to modify read-only scalars [perl #91850].
=item *
Freeing $_ inside a C<grep> or C<map> block, a code block embedded in a
regular expression, or an @INC filter (a subroutine returned by a
subroutine in @INC) used to result in double frees or crashes
[perl #91880, #92254, #92256].
=item *
C<eval> returns C<undef> in scalar context or an empty list in list
context when there is a run-time error. When C<eval> was passed a
string in list context and a syntax error occurred, it used to return a
list containing a single undefined element. Now it returns an empty
list in list context for all errors [perl #80630].
=item *
C<goto &func> no longer crashes, but produces an error message, when
the unwinding of the current subroutine's scope fires a destructor that
undefines the subroutine being "goneto" [perl #99850].
=item *
Perl now holds an extra reference count on the package that code is
currently compiling in. This means that the following code no longer
crashes [perl #101486]:
package Foo;
BEGIN {*Foo:: = *Bar::}
sub foo;
=item *
The C<x> repetition operator no longer crashes on 64-bit builds with large
repeat counts [perl #94560].
=item *
Calling C<require> on an implicit C<$_> when C<*CORE::GLOBAL::require> has
been overridden does not segfault anymore, and C<$_> is now passed to the
overriding subroutine [perl #78260].
=item *
C<use> and C<require> are no longer affected by the I/O layers active in
the caller's scope (enabled by L<open.pm|open>) [perl #96008].
=item *
C<our $::é; $é> (which is invalid) no longer produces the "Compilation
error at lib/utf8_heavy.pl..." error message, which it started emitting in
5.10.0 [perl #99984].
=item *
On 64-bit systems, C<read()> now understands large string offsets beyond
the 32-bit range.
=item *
Errors that occur when processing subroutine attributes no longer cause the
subroutine's op tree to leak.
=item *
Passing the same constant subroutine to both C<index> and C<formline> no
longer causes one or the other to fail [perl #89218]. (5.14.1)
=item *
List assignment to lexical variables declared with attributes in the same
statement (C<my ($x,@y) : blimp = (72,94)>) stopped working in Perl 5.8.0.
It has now been fixed.
=item *
Perl 5.10.0 introduced some faulty logic that made "U*" in the middle of
a pack template equivalent to "U0" if the input string was empty. This has
been fixed [perl #90160]. (5.14.2)
=item *
Destructors on objects were not called during global destruction on objects
that were not referenced by any scalars. This could happen if an array
element were blessed (e.g., C<bless \$a[0]>) or if a closure referenced a
blessed variable (C<bless \my @a; sub foo { @a }>).
Now there is an extra pass during global destruction to fire destructors on
any objects that might be left after the usual passes that check for
objects referenced by scalars [perl #36347].
=item *
Fixed a case where it was possible that a freed buffer may have been read
from when parsing a here document [perl #90128]. (5.14.1)
=item *
C<each(I<ARRAY>)> is now wrapped in C<defined(...)>, like C<each(I<HASH>)>,
inside a C<while> condition [perl #90888].
=item *
A problem with context propagation when a C<do> block is an argument to
C<return> has been fixed. It used to cause C<undef> to be returned in
certain cases of a C<return> inside an C<if> block which itself is followed by
another C<return>.
=item *
Calling C<index> with a tainted constant no longer causes constants in
subsequently compiled code to become tainted [perl #64804].
=item *
Infinite loops like C<1 while 1> used to stop C<strict 'subs'> mode from
working for the rest of the block.
=item *
For list assignments like C<($a,$b) = ($b,$a)>, Perl has to make a copy of
the items on the right-hand side before assignment them to the left. For
efficiency's sake, it assigns the values on the right straight to the items
on the left if no one variable is mentioned on both sides, as in C<($a,$b) =
($c,$d)>. The logic for determining when it can cheat was faulty, in that
C<&&> and C<||> on the right-hand side could fool it. So C<($a,$b) =
$some_true_value && ($b,$a)> would end up assigning the value of C<$b> to
both scalars.
=item *
Perl no longer tries to apply lvalue context to the string in
C<("string", $variable) ||= 1> (which used to be an error). Since the
left-hand side of C<||=> is evaluated in scalar context, that's a scalar
comma operator, which gives all but the last item void context. There is
no such thing as void lvalue context, so it was a mistake for Perl to try
to force it [perl #96942].
=item *
C<caller> no longer leaks memory when called from the DB package if
C<@DB::args> was assigned to after the first call to C<caller>. L<Carp>
was triggering this bug [perl #97010]. (5.14.2)
=item *
C<close> and similar filehandle functions, when called on built-in global
variables (like C<$+>), used to die if the variable happened to hold the
undefined value, instead of producing the usual "Use of uninitialized
value" warning.
=item *
When autovivified file handles were introduced in Perl 5.6.0, C<readline>
was inadvertently made to autovivify when called as C<readline($foo)> (but
not as C<E<lt>$fooE<gt>>). It has now been fixed never to autovivify.
=item *
Calling an undefined anonymous subroutine (e.g., what $x holds after
C<undef &{$x = sub{}}>) used to cause a "Not a CODE reference" error, which
has been corrected to "Undefined subroutine called" [perl #71154].
=item *
Causing C<@DB::args> to be freed between uses of C<caller> no longer
results in a crash [perl #93320].
=item *
C<setpgrp($foo)> used to be equivalent to C<($foo, setpgrp)>, because
C<setpgrp> was ignoring its argument if there was just one. Now it is
equivalent to C<setpgrp($foo,0)>.
=item *
C<shmread> was not setting the scalar flags correctly when reading from
shared memory, causing the existing cached numeric representation in the
scalar to persist [perl #98480].
=item *
C<++> and C<--> now work on copies of globs, instead of dying.
=item *
C<splice()> doesn't warn when truncating
You can now limit the size of an array using C<splice(@a,MAX_LEN)> without
worrying about warnings.
=item *
C<< $$ >> is no longer tainted. Since this value comes directly from
C<< getpid() >>, it is always safe.
=item *
The parser no longer leaks a filehandle if STDIN was closed before parsing
started [perl #37033].
=item *
C<< die; >> with a non-reference, non-string, or magical (e.g., tainted)
value in $@ now properly propagates that value [perl #111654].
=back
=head1 Known Problems
=over 4
=item *
On Solaris, we have two kinds of failure.
If F<make> is Sun's F<make>, we get an error about a badly formed macro
assignment in the F<Makefile>. That happens when F<./Configure> tries to
make depends. F<Configure> then exits 0, but further F<make>-ing fails.
If F<make> is F<gmake>, F<Configure> completes, then we get errors related
to F</usr/include/stdbool.h>
=item *
On Win32, a number of tests hang unless STDERR is redirected. The cause of
this is still under investigation.
=item *
When building as root with a umask that prevents files from being
other-readable, F<t/op/filetest.t> will fail. This is a test bug, not a
bug in perl's behavior.
=item *
Configuring with a recent gcc and link-time-optimization, such as
C<Configure -Doptimize='-O2 -flto'> fails
because the optimizer optimizes away some of Configure's tests. A
workaround is to omit the C<-flto> flag when running Configure, but add
it back in while actually building, something like
sh Configure -Doptimize=-O2
make OPTIMIZE='-O2 -flto'
=item *
The following CPAN modules have test failures with perl 5.16. Patches have
been submitted for all of these, so hopefully there will be new releases
soon:
=over
=item *
L<Date::Pcalc> version 6.1
=item *
L<Module::CPANTS::Analyse> version 0.85
This fails due to problems in L<Module::Find> 0.10 and L<File::MMagic>
1.27.
=item *
L<PerlIO::Util> version 0.72
=back
=back
=head1 Acknowledgements
Perl 5.16.0 represents approximately 12 months of development since Perl
5.14.0 and contains approximately 590,000 lines of changes across 2,500
files from 139 authors.
Perl continues to flourish into its third decade thanks to a vibrant
community of users and developers. The following people are known to
have contributed the improvements that became Perl 5.16.0:
Aaron Crane, Abhijit Menon-Sen, Abigail, Alan Haggai Alavi, Alberto
Simões, Alexandr Ciornii, Andreas König, Andy Dougherty, Aristotle
Pagaltzis, Bo Johansson, Bo Lindbergh, Breno G. de Oliveira, brian d
foy, Brian Fraser, Brian Greenfield, Carl Hayter, Chas. Owens,
Chia-liang Kao, Chip Salzenberg, Chris 'BinGOs' Williams, Christian
Hansen, Christopher J. Madsen, chromatic, Claes Jacobsson, Claudio
Ramirez, Craig A. Berry, Damian Conway, Daniel Kahn Gillmor, Darin
McBride, Dave Rolsky, David Cantrell, David Golden, David Leadbeater,
David Mitchell, Dee Newcum, Dennis Kaarsemaker, Dominic Hargreaves,
Douglas Christopher Wilson, Eric Brine, Father Chrysostomos, Florian
Ragwitz, Frederic Briere, George Greer, Gerard Goossen, Gisle Aas,
H.Merijn Brand, Hojung Youn, Ian Goodacre, James E Keenan, Jan Dubois,
Jerry D. Hedden, Jesse Luehrs, Jesse Vincent, Jilles Tjoelker, Jim
Cromie, Jim Meyering, Joel Berger, Johan Vromans, Johannes Plunien, John
Hawkinson, John P. Linderman, John Peacock, Joshua ben Jore, Juerd
Waalboer, Karl Williamson, Karthik Rajagopalan, Keith Thompson, Kevin J.
Woolley, Kevin Ryde, Laurent Dami, Leo Lapworth, Leon Brocard, Leon
Timmermans, Louis Strous, Lukas Mai, Marc Green, Marcel Grünauer, Mark
A. Stratman, Mark Dootson, Mark Jason Dominus, Martin Hasch, Matthew
Horsfall, Max Maischein, Michael G Schwern, Michael Witten, Mike
Sheldrake, Moritz Lenz, Nicholas Clark, Niko Tyni, Nuno Carvalho, Pau
Amma, Paul Evans, Paul Green, Paul Johnson, Perlover, Peter John Acklam,
Peter Martini, Peter Scott, Phil Monsen, Pino Toscano, Rafael
Garcia-Suarez, Rainer Tammer, Reini Urban, Ricardo Signes, Robin Barker,
Rodolfo Carvalho, Salvador Fandiño, Sam Kimbrel, Samuel Thibault, Shawn
M Moore, Shigeya Suzuki, Shirakata Kentaro, Shlomi Fish, Sisyphus,
Slaven Rezic, Spiros Denaxas, Steffen Müller, Steffen Schwigon, Stephen
Bennett, Stephen Oberholtzer, Stevan Little, Steve Hay, Steve Peters,
Thomas Sibley, Thorsten Glaser, Timothe Litt, Todd Rinaldo, Tom
Christiansen, Tom Hukins, Tony Cook, Vadim Konovalov, Vincent Pit,
Vladimir Timofeev, Walt Mankowski, Yves Orton, Zefram, Zsbán Ambrus,
Ævar Arnfjörð Bjarmason.
The list above is almost certainly incomplete as it is automatically
generated from version control history. In particular, it does not
include the names of the (very much appreciated) contributors who
reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the CPAN
modules included in Perl's core. We're grateful to the entire CPAN
community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors,
please see the F<AUTHORS> file in the Perl source distribution.
=head1 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 L<http://rt.perl.org/perlbug/>. There may also be
information at L<http://www.perl.org/>, the Perl Home Page.
If you believe you have an unreported bug, please run the L<perlbug>
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 C<perl -V>, will be sent off to perlbug@perl.org to be
analysed by the Perl porting team.
If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please
send it to perl5-security-report@perl.org. This points to a closed
subscription unarchived mailing list, which includes all core
committers, who will be able to help assess the impact of issues, figure
out a resolution, and help co-ordinate the release of patches to
mitigate or fix the problem across all platforms on which Perl is
supported. Please use this address only for security issues in the Perl
core, not for modules independently distributed on CPAN.
=head1 SEE ALSO
The F<Changes> file for an explanation of how to view exhaustive details
on what changed.
The F<INSTALL> file for how to build Perl.
The F<README> file for general stuff.
The F<Artistic> and F<Copying> files for copyright information.
=cut