PERL5140DELTA(1) Perl Programmers Reference Guide PERL5140DELTA(1)
NAME
perl5140delta - what is new for perl v5.14.0
DESCRIPTION
This document describes differences between the 5.12.0 release and the 5.14.0 release.
If you are upgrading from an earlier release such as 5.10.0, first read perl5120delta, which describes
differences between 5.10.0 and 5.12.0.
Some of the bug fixes in this release have been backported to subsequent releases of 5.12.x. Those are
indicated with the 5.12.x version in parentheses.
Notice
As described in perlpolicy, the release of Perl 5.14.0 marks the official end of support for Perl 5.10. Users
of Perl 5.10 or earlier should consider upgrading to a more recent release of Perl.
Core Enhancements
Unicode
Unicode Version 6.0 is now supported (mostly)
Perl comes with the Unicode 6.0 data base updated with Corrigendum #8
<http://www.unicode.org/versions/corrigendum8.html>, with one exception noted below. See
<http://unicode.org/versions/Unicode6.0.0/> for details on the new release. Perl does not support any Unicode
provisional properties, including the new ones for this release.
Unicode 6.0 has chosen to use the name "BELL" for the character at U+1F514, which is a symbol that looks like
a bell, and is used in Japanese cell phones. This conflicts with the long-standing Perl usage of having
"BELL" mean the ASCII "BEL" character, U+0007. In Perl 5.14, "\N{BELL}" continues to mean U+0007, but its use
generates a deprecation warning message unless such warnings are turned off. The new name for U+0007 in Perl
is "ALERT", which corresponds nicely with the existing shorthand sequence for it, "\a". "\N{BEL}" means
U+0007, with no warning given. The character at U+1F514 has no name in 5.14, but can be referred to by
"\N{U+1F514}". In Perl 5.16, "\N{BELL}" will refer to U+1F514; all code that uses "\N{BELL}" should be
converted to use "\N{ALERT}", "\N{BEL}", or "\a" before upgrading.
Full functionality for "use feature 'unicode_strings'"
This release provides full functionality for "use feature 'unicode_strings'". Under its scope, all string
operations executed and regular expressions compiled (even if executed outside its scope) have Unicode
semantics. See "the 'unicode_strings' feature" in feature. However, see "Inverted bracketed character
classes and multi-character folds", below.
This feature avoids most forms of the "Unicode Bug" (see "The "Unicode Bug"" in perlunicode for details). If
there is any possibility that your code will process Unicode strings, you are strongly encouraged to use this
subpragma to avoid nasty surprises.
"\N{NAME}" and "charnames" enhancements
· "\N{NAME}" and "charnames::vianame" now know about the abbreviated character names listed by Unicode, such
as NBSP, SHY, LRO, ZWJ, etc.; all customary abbreviations for the C0 and C1 control characters (such as
ACK, BEL, CAN, etc.); and a few new variants of some C1 full names that are in common usage.
· Unicode has several named character sequences, in which particular sequences of code points are given
names. "\N{NAME}" now recognizes these.
· "\N{NAME}", "charnames::vianame", and "charnames::viacode" now know about every character in Unicode. In
earlier releases of Perl, they didn't know about the Hangul syllables nor several CJK
See charnames for details on all these changes.
New warnings categories for problematic (non-)Unicode code points.
Three new warnings subcategories of "utf8" have been added. These allow you to turn off some "utf8" warnings,
while allowing other warnings to remain on. The three categories are: "surrogate" when UTF-16 surrogates are
encountered; "nonchar" when Unicode non-character code points are encountered; and "non_unicode" when code
points above the legal Unicode maximum of 0x10FFFF are encountered.
Any unsigned value can be encoded as a character
With this release, Perl is adopting a model that any unsigned value can be treated as a code point and encoded
internally (as utf8) without warnings, not just the code points that are legal in Unicode. However, unless
utf8 or the corresponding sub-category (see previous item) of lexical warnings have been explicitly turned
off, outputting or executing a Unicode-defined operation such as upper-casing on such a code point generates a
warning. Attempting to input these using strict rules (such as with the ":encoding(UTF-8)" layer) will
continue to fail. Prior to this release, handling was inconsistent and in places, incorrect.
Unicode non-characters, some of which previously were erroneously considered illegal in places by Perl,
contrary to the Unicode Standard, are now always legal internally. Inputting or outputting them works the
same as with the non-legal Unicode code points, because the Unicode Standard says they are (only) illegal for
"open interchange".
Unicode database files not installed
The Unicode database files are no longer installed with Perl. This doesn't affect any functionality in Perl
and saves significant disk space. If you need these files, you can download them from
<http://www.unicode.org/Public/zipped/6.0.0/>.
Regular Expressions
"(?^...)" construct signifies default modifiers
An ASCII caret "^" immediately following a "(?" in a regular expression now means that the subexpression does
not inherit surrounding modifiers such as "/i", but reverts to the Perl defaults. Any modifiers following the
caret override the defaults.
Stringification of regular expressions now uses this notation. For example, "qr/hlagh/i" would previously be
stringified as "(?i-xsm:hlagh)", but now it's stringified as "(?^i:hlagh)".
The main purpose of this change is to allow tests that rely on the stringification not to have to change
whenever new modifiers are added. See "Extended Patterns" in perlre.
This change is likely to break code that compares stringified regular expressions with fixed strings
containing "?-xism".
"/d", "/l", "/u", and "/a" modifiers
Four new regular expression modifiers have been added. These are mutually exclusive: one only can be turned
on at a time.
· The "/l" modifier says to compile the regular expression as if it were in the scope of "use locale", even
if it is not.
"k" =~ /\N{KELVIN SIGN}/ai
"\xDF" =~ /ss/ai
match but
"k" =~ /\N{KELVIN SIGN}/aai
"\xDF" =~ /ss/aai
do not match.
See "Modifiers" in perlre for more detail.
Non-destructive substitution
The substitution ("s///") and transliteration ("y///") operators now support an "/r" option that copies the
input variable, carries out the substitution on the copy, and returns the result. The original remains
unmodified.
my $old = "cat";
my $new = $old =~ s/cat/dog/r;
# $old is "cat" and $new is "dog"
This is particularly useful with "map". See perlop for more examples.
Re-entrant regular expression engine
It is now safe to use regular expressions within "(?{...})" and "(??{...})" code blocks inside regular
expressions.
These blocks are still experimental, however, and still have problems with lexical ("my") variables and
abnormal exiting.
"use re '/flags'"
The "re" pragma now has the ability to turn on regular expression flags till the end of the lexical scope:
use re "/x";
"foo" =~ / (.+) /; # /x implied
See "'/flags' mode" in re for details.
\o{...} for octals
There is a new octal escape sequence, "\o", in doublequote-like contexts. This construct allows large octal
ordinals beyond the current max of 0777 to be represented. It also allows you to specify a character in octal
which can safely be concatenated with other regex snippets and which won't be confused with being a
backreference to a regex capture group. See "Capture groups" in perlre.
Add "\p{Titlecase}" as a synonym for "\p{Title}"
This synonym is added for symmetry with the Unicode property names "\p{Uppercase}" and "\p{Lowercase}".
Regular expression debugging output improvement
Perl.
All builtin functions that operate directly on array or hash containers now also accept unblessed hard
references to arrays or hashes:
|----------------------------+---------------------------|
| Traditional syntax | Terse syntax |
|----------------------------+---------------------------|
| push @$arrayref, @stuff | push $arrayref, @stuff |
| unshift @$arrayref, @stuff | unshift $arrayref, @stuff |
| pop @$arrayref | pop $arrayref |
| shift @$arrayref | shift $arrayref |
| splice @$arrayref, 0, 2 | splice $arrayref, 0, 2 |
| keys %$hashref | keys $hashref |
| keys @$arrayref | keys $arrayref |
| values %$hashref | values $hashref |
| values @$arrayref | values $arrayref |
| ($k,$v) = each %$hashref | ($k,$v) = each $hashref |
| ($k,$v) = each @$arrayref | ($k,$v) = each $arrayref |
|----------------------------+---------------------------|
This allows these builtin functions to act on long dereferencing chains or on the return value of subroutines
without needing to wrap them in "@{}" or "%{}":
push @{$obj->tags}, $new_tag; # old way
push $obj->tags, $new_tag; # new way
for ( keys %{$hoh->{genres}{artists}} ) {...} # old way
for ( keys $hoh->{genres}{artists} ) {...} # new way
Single term prototype
The "+" prototype is a special alternative to "$" that acts like "\[@%]" when given a literal array or hash
variable, but will otherwise force scalar context on the argument. See "Prototypes" in perlsub.
"package" block syntax
A package declaration can now contain a code block, in which case the declaration is in scope inside that
block only. So "package Foo { ... }" is precisely equivalent to "{ package Foo; ... }". It also works with a
version number in the declaration, as in "package Foo 1.2 { ... }", which is its most attractive feature. See
perlfunc.
Statement labels can appear in more places
Statement labels can now occur before any type of statement or declaration, such as "package".
Stacked labels
Multiple statement labels can now appear before a single statement.
Uppercase X/B allowed in hexadecimal/binary literals
Literals may now use either upper case "0X..." or "0B..." prefixes, in addition to the already supported
"0x..." and "0b..." syntax [perl #76296].
destructor code running during unwinding. Previously, the exception was written into $@ early in the
throwing process, and would be overwritten if "eval" was used internally in the destructor for an object
that had to be freed while exiting from the outer "eval". Now the exception is written into $@ last thing
before exiting the outer "eval", so the code running immediately thereafter can rely on the value in $@
correctly corresponding to that "eval". ($@ is still also set before exiting the "eval", for the sake of
destructors that rely on this.)
Likewise, a "local $@" inside an "eval" no longer clobbers any exception thrown in its scope. Previously,
the restoration of $@ upon unwinding would overwrite any exception being thrown. Now the exception gets
to the "eval" anyway. So "local $@" is safe before a "die".
Exceptions thrown from object destructors no longer modify the $@ of the surrounding context. (If the
surrounding context was exception unwinding, this used to be another way to clobber the exception being
thrown.) Previously such an exception was sometimes emitted as a warning, and then either was string-
appended to the surrounding $@ or completely replaced the surrounding $@, depending on whether that
exception and the surrounding $@ were strings or objects. Now, an exception in this situation is always
emitted as a warning, leaving the surrounding $@ untouched. In addition to object destructors, this also
affects any function call run by XS code using the "G_KEEPERR" flag.
· Warnings for "warn" can now be objects in the same way as exceptions for "die". If an object-based
warning gets the default handling of writing to standard error, it is stringified as before with the
filename and line number appended. But a $SIG{__WARN__} handler now receives an object-based warning as
an object, where previously it was passed the result of stringifying the object.
Other Enhancements
Assignment to $0 sets the legacy process name with prctl() on Linux
On Linux the legacy process name is now set with prctl(2), in addition to altering the POSIX name via
"argv[0]", as Perl has done since version 4.000. Now system utilities that read the legacy process name such
as ps, top, and killall recognize the name you set when assigning to $0. The string you supply is truncated
at 16 bytes; this limitation is imposed by Linux.
srand() now returns the seed
This allows programs that need to have repeatable results not to have to come up with their own seed-
generating mechanism. Instead, they can use srand() and stash the return value for future use. One example
is a test program with too many combinations to test comprehensively in the time available for each run. It
can test a random subset each time and, should there be a failure, log the seed used for that run so this can
later be used to produce the same results.
printf-like functions understand post-1980 size modifiers
Perl's printf and sprintf operators, and Perl's internal printf replacement function, now understand the C90
size modifiers "hh" ("char"), "z" ("size_t"), and "t" ("ptrdiff_t"). Also, when compiled with a C99 compiler,
Perl now understands the size modifier "j" ("intmax_t") (but this is not portable).
So, for example, on any modern machine, "sprintf("%hhd", 257)" returns "1".
New global variable "${^GLOBAL_PHASE}"
A new global variable, "${^GLOBAL_PHASE}", has been added to allow introspection of the current phase of the
Perl interpreter. It's explained in detail in "${^GLOBAL_PHASE}" in perlvar and in "BEGIN, UNITCHECK, CHECK,
INIT and END" in perlmod.
if that method exists.
This is particularly useful for suppressing the default actions of a "Devel::*" module's "import" method
whilst still loading it for debugging.
Filehandle method calls load IO::File on demand
When a method call on a filehandle would die because the method cannot be resolved and IO::File has not been
loaded, Perl now loads IO::File via "require" and attempts method resolution again:
open my $fh, ">", $file;
$fh->binmode(":raw"); # loads IO::File and succeeds
This also works for globs like "STDOUT", "STDERR", and "STDIN":
STDOUT->autoflush(1);
Because this on-demand load happens only if method resolution fails, the legacy approach of manually loading
an IO::File parent class for partial method support still works as expected:
use IO::Handle;
open my $fh, ">", $file;
$fh->autoflush(1); # IO::File not loaded
Improved IPv6 support
The "Socket" module provides new affordances for IPv6, including implementations of the
"Socket::getaddrinfo()" and "Socket::getnameinfo()" functions, along with related constants and a handful of
new functions. See Socket.
DTrace probes now include package name
The "DTrace" probes now include an additional argument, "arg3", which contains the package the subroutine
being entered or left was compiled in.
For example, using the following DTrace script:
perl$target:::sub-entry
{
printf("%s::%s\n", copyinstr(arg0), copyinstr(arg3));
}
and then running:
$ perl -e 'sub test { }; test'
"DTrace" will print:
main::test
New C APIs
See "Internal Changes".
Security
In addition to the sections that follow, see "C API Changes".
Regular Expressions and String Escapes
Inverted bracketed character classes and multi-character folds
Some characters match a sequence of two or three characters in "/i" regular expression matching under Unicode
rules. One example is "LATIN SMALL LETTER SHARP S" which matches the sequence "ss".
'ss' =~ /\A[\N{LATIN SMALL LETTER SHARP S}]\z/i # Matches
This, however, can lead to very counter-intuitive results, especially when inverted. Because of this, Perl
5.14 does not use multi-character "/i" matching in inverted character classes.
'ss' =~ /\A[^\N{LATIN SMALL LETTER SHARP S}]+\z/i # ???
This should match any sequences of characters that aren't the "SHARP S" nor what "SHARP S" matches under "/i".
"s" isn't "SHARP S", but Unicode says that "ss" is what "SHARP S" matches under "/i". So which one "wins"? Do
you fail the match because the string has "ss" or accept it because it has an "s" followed by another "s"?
Earlier releases of Perl did allow this multi-character matching, but due to bugs, it mostly did not work.
\400-\777
In certain circumstances, "\400"-"\777" in regexes have behaved differently than they behave in all other
doublequote-like contexts. Since 5.10.1, Perl has issued a deprecation warning when this happens. Now, these
literals behave the same in all doublequote-like contexts, namely to be equivalent to "\x{100}"-"\x{1FF}",
with no deprecation warning.
Use of "\400"-"\777" in the command-line option -0 retain their conventional meaning. They slurp whole input
files; previously, this was documented only for -0777.
Because of various ambiguities, you should use the new "\o{...}" construct to represent characters in octal
instead.
Most "\p{}" properties are now immune to case-insensitive matching
For most Unicode properties, it doesn't make sense to have them match differently under "/i" case-insensitive
matching. Doing so can lead to unexpected results and potential security holes. For example
m/\p{ASCII_Hex_Digit}+/i
could previously match non-ASCII characters because of the Unicode matching rules (although there were several
bugs with this). Now matching under "/i" gives the same results as non-"/i" matching except for those few
properties where people have come to expect differences, namely the ones where casing is an integral part of
their meaning, such as "m/\p{Uppercase}/i" and "m/\p{Lowercase}/i", both of which match the same code points
as matched by "m/\p{Cased}/i". Details are in "Unicode Properties" in perlrecharclass.
User-defined property handlers that need to match differently under "/i" must be changed to read the new
boolean parameter passed to them, which is non-zero if case-insensitive matching is in effect and 0 otherwise.
See "User-Defined Character Properties" in perlunicode.
\p{} implies Unicode semantics
Specifying a Unicode property in the pattern indicates that the pattern is meant for matching according to
Default regular expression modifiers are now notated using "(?^...)". Code relying on the old stringification
will fail. This is so that when new modifiers are added, such code won't have to keep changing each time this
happens, because the stringification will automatically incorporate the new modifiers.
Code that needs to work properly with both old- and new-style regexes can avoid the whole issue by using (for
perls since 5.9.5; see re):
use re qw(regexp_pattern);
my ($pat, $mods) = regexp_pattern($re_ref);
If the actual stringification is important or older Perls need to be supported, you can use something like the
following:
# Accept both old and new-style stringification
my $modifiers = (qr/foobar/ =~ /\Q(?^/) ? "^" : "-xism";
And then use $modifiers instead of "-xism".
Run-time code blocks in regular expressions inherit pragmata
Code blocks in regular expressions ("(?{...})" and "(??{...})") previously did not inherit pragmata (strict,
warnings, etc.) if the regular expression was compiled at run time as happens in cases like these two:
use re "eval";
$foo =~ $bar; # when $bar contains (?{...})
$foo =~ /$bar(?{ $finished = 1 })/;
This bug has now been fixed, but code that relied on the buggy behaviour may need to be fixed to account for
the correct behaviour.
Stashes and Package Variables
Localised tied hashes and arrays are no longed tied
In the following:
tie @a, ...;
{
local @a;
# here, @a is a now a new, untied array
}
# here, @a refers again to the old, tied array
Earlier versions of Perl incorrectly tied the new local array. This has now been fixed. This fix could
however potentially cause a change in behaviour of some code.
Stashes are now always defined
"defined %Foo::" now always returns true, even when no symbols have yet been defined in that package.
This is a side-effect of removing a special-case kludge in the tokeniser, added for 5.10.0, to hide side-
effects of changes to the internal storage of hashes. The fix drastically reduces hashes' memory overhead.
Calling defined on a stash has been deprecated since 5.6.0, warned on lexicals since 5.6.0, and warned for
Dereferencing typeglobs
If you assign a typeglob to a scalar variable:
$glob = *foo;
the glob that is copied to $glob is marked with a special flag indicating that the glob is just a copy. This
allows subsequent assignments to $glob to overwrite the glob. The original glob, however, is immutable.
Some Perl operators did not distinguish between these two types of globs. This would result in strange
behaviour in edge cases: "untie $scalar" would not untie the scalar if the last thing assigned to it was a
glob (because it treated it as "untie *$scalar", which unties a handle). Assignment to a glob slot (such as
"*$glob = \@some_array") would simply assign "\@some_array" to $glob.
To fix this, the "*{}" operator (including its *foo and *$foo forms) has been modified to make a new immutable
glob if its operand is a glob copy. This allows operators that make a distinction between globs and scalars
to be modified to treat only immutable globs as globs. ("tie", "tied" and "untie" have been left as they are
for compatibility's sake, but will warn. See "Deprecations".)
This causes an incompatible change in code that assigns a glob to the return value of "*{}" when that operator
was passed a glob copy. Take the following code, for instance:
$glob = *foo;
*$glob = *bar;
The *$glob on the second line returns a new immutable glob. That new glob is made an alias to *bar. Then it
is discarded. So the second assignment has no effect.
See <http://rt.perl.org/rt3/Public/Bug/Display.html?id=77810> for more detail.
Magic variables outside the main package
In previous versions of Perl, magic variables like $!, %SIG, etc. would "leak" into other packages. So
%foo::SIG could be used to access signals, "${"foo::!"}" (with strict mode off) to access C's "errno", etc.
This was a bug, or an "unintentional" feature, which caused various ill effects, such as signal handlers being
wiped when modules were loaded, etc.
This has been fixed (or the feature has been removed, depending on how you see it).
local($_) strips all magic from $_
local() on scalar variables gives them a new value but keeps all their magic intact. This has proven
problematic for the default scalar variable $_, where perlsub recommends that any subroutine that assigns to
$_ should first localize it. This would throw an exception if $_ is aliased to a read-only variable, and
could in general have various unintentional side-effects.
Therefore, as an exception to the general rule, local($_) will not only assign a new value to $_, but also
remove all existing magic from it as well.
Parsing of package and variable names
Parsing the names of packages and package variables has changed: multiple adjacent pairs of colons, as in
"foo::::bar", are now all treated as package separators.
break when undef;
"integer" when /^[+-]?[0-9]+$/;
"float" when /^[+-]?[0-9]+(?:\.[0-9]+)?$/;
"unknown";
}
};
See "Return value" in perlsyn for details.
Change in parsing of certain prototypes
Functions declared with the following prototypes now behave correctly as unary functions:
*
\$ \% \@ \* \&
\[...]
;$ ;*
;\$ ;\% etc.
;\[...]
Due to this bug fix [perl #75904], functions using the "(*)", "(;$)" and "(;*)" prototypes are parsed with
higher precedence than before. So in the following example:
sub foo(;$);
foo $a < $b;
the second line is now parsed correctly as "foo($a) < $b", rather than "foo($a < $b)". This happens when one
of these operators is used in an unparenthesised argument:
< > <= >= lt gt le ge
== != <=> eq ne cmp ~~
&
| ^
&&
|| //
.. ...
?:
= += -= *= etc.
, =>
Smart-matching against array slices
Previously, the following code resulted in a successful match:
my @a = qw(a y0 z);
my @b = qw(a x0 z);
@a[0 .. $#b] ~~ @b;
This odd behaviour has now been fixed [perl #77468].
Negation treats strings differently from before
The unary negation operator, "-", now treats strings that look like numbers as numbers [perl #57706].
a syntax error. This allows future use of ":=" as a new token.
Outside the core's tests for it, we find no Perl 5 code on CPAN using this construction, so we believe that
this change will have little impact on real-world codebases.
If it is absolutely necessary to have empty attribute lists (for example, because of a code generator), simply
avoid the error by adding a space before the "=".
Change in the parsing of identifiers
Characters outside the Unicode "XIDStart" set are no longer allowed at the beginning of an identifier. This
means that certain accents and marks that normally follow an alphabetic character may no longer be the first
character of an identifier.
Threads and Processes
Directory handles not copied to threads
On systems other than Windows that do not have a "fchdir" function, newly-created threads no longer inherit
directory handles from their parent threads. Such programs would usually have crashed anyway [perl #75154].
"close" on shared pipes
To avoid deadlocks, the "close" function no longer waits for the child process to exit if the underlying file
descriptor is still in use by another thread. It returns true in such cases.
fork() emulation will not wait for signalled children
On Windows parent processes would not terminate until all forked children had terminated first. However,
"kill("KILL", ...)" is inherently unstable on pseudo-processes, and "kill("TERM", ...)" might not get
delivered if the child is blocked in a system call.
To avoid the deadlock and still provide a safe mechanism to terminate the hosting process, Perl now no longer
waits for children that have been sent a SIGTERM signal. It is up to the parent process to waitpid() for
these children if child-cleanup processing must be allowed to finish. However, it is also then the
responsibility of the parent to avoid the deadlock by making sure the child process can't be blocked on I/O.
See perlfork for more information about the fork() emulation on Windows.
Configuration
Naming fixes in Policy_sh.SH may invalidate Policy.sh
Several long-standing typos and naming confusions in Policy_sh.SH have been fixed, standardizing on the
variable names used in config.sh.
This will change the behaviour of Policy.sh if you happen to have been accidentally relying on its incorrect
behaviour.
Perl source code is read in text mode on Windows
Perl scripts used to be read in binary mode on Windows for the benefit of the ByteLoader module (which is no
longer part of core Perl). This had the side-effect of breaking various operations on the "DATA" filehandle,
including seek()/tell(), and even simply reading from "DATA" after filehandles have been flushed by a call to
system(), backticks, fork() etc.
The backslash-c construct was designed as a way of specifying non-printable characters, but there were no
restrictions (on ASCII platforms) on what the character following the "c" could be. Now, a deprecation
warning is raised if that character isn't an ASCII character. Also, a deprecation warning is raised for "\c{"
(which is the same as simply saying ";").
"\b{" and "\B{"
In regular expressions, a literal "{" immediately following a "\b" (not in a bracketed character class) or a
"\B{" is now deprecated to allow for its future use by Perl itself.
Perl 4-era .pl libraries
Perl bundles a handful of library files that predate Perl 5. This bundling is now deprecated for most of
these files, which are now available from CPAN. The affected files now warn when run, if they were installed
as part of the core.
This is a mandatory warning, not obeying -X or lexical warning bits. The warning is modelled on that supplied
by deprecate.pm for deprecated-in-core .pm libraries. It points to the specific CPAN distribution that
contains the .pl libraries. The CPAN versions, of course, do not generate the warning.
List assignment to $[
Assignment to $[ was deprecated and started to give warnings in Perl version 5.12.0. This version of Perl
(5.14) now also emits a warning when assigning to $[ in list context. This fixes an oversight in 5.12.0.
Use of qw(...) as parentheses
Historically the parser fooled itself into thinking that "qw(...)" literals were always enclosed in
parentheses, and as a result you could sometimes omit parentheses around them:
for $x qw(a b c) { ... }
The parser no longer lies to itself in this way. Wrap the list literal in parentheses like this:
for $x (qw(a b c)) { ... }
This is being deprecated because the parentheses in "for $i (1,2,3) { ... }" are not part of expression
syntax. They are part of the statement syntax, with the "for" statement wanting literal parentheses. The
synthetic parentheses that a "qw" expression acquired were only intended to be treated as part of expression
syntax.
Note that this does not change the behaviour of cases like:
use POSIX qw(setlocale localeconv);
our @EXPORT = qw(foo bar baz);
where parentheses were never required around the expression.
"\N{BELL}"
This is because Unicode is using that name for a different character. See "Unicode Version 6.0 is now
supported (mostly)" for more explanation.
"?PATTERN?"
"?PATTERN?" (without the initial "m") has been deprecated and now produces a warning. This is to allow future
use of "?" in new operators. The match-once functionality is still available as "m?PATTERN?".
Tie functions on scalars holding typeglobs
Calling a tie function ("tie", "tied", "untie") with a scalar argument acts on a filehandle if the scalar
Deprecated modules
The following module will be removed from the core distribution in a future release, and should be installed
from CPAN instead. Distributions on CPAN that require this should add it to their prerequisites. The core
version of these module now issues a deprecation warning.
If you ship a packaged version of Perl, either alone or as part of a larger system, then you should carefully
consider the repercussions of core module deprecations. You may want to consider shipping your default build
of Perl with a package for the deprecated module that installs into "vendor" or "site" Perl library
directories. This will inhibit the deprecation warnings.
Alternatively, you may want to consider patching lib/deprecate.pm to provide deprecation warnings specific to
your packaging system or distribution of Perl, consistent with how your packaging system or distribution
manages a staged transition from a release where the installation of a single package provides the given
functionality, to a later release where the system administrator needs to know to install multiple packages to
get that same functionality.
You can silence these deprecation warnings by installing the module in question from CPAN. To install the
latest version of it by role rather than by name, just install "Task::Deprecations::5_14".
Devel::DProf
We strongly recommend that you install and use Devel::NYTProf instead of Devel::DProf, as Devel::NYTProf
offers significantly improved profiling and reporting.
Performance Enhancements
"Safe signals" optimisation
Signal dispatch has been moved from the runloop into control ops. This should give a few percent speed
increase, and eliminates nearly all the speed penalty caused by the introduction of "safe signals" in 5.8.0.
Signals should still be dispatched within the same statement as they were previously. If this does not
happen, or if you find it possible to create uninterruptible loops, this is a bug, and reports are encouraged
of how to recreate such issues.
Optimisation of shift() and pop() calls without arguments
Two fewer OPs are used for shift() and pop() calls with no argument (with implicit @_). This change makes
shift() 5% faster than "shift @_" on non-threaded perls, and 25% faster on threaded ones.
Optimisation of regexp engine string comparison work
The "foldEQ_utf8" API function for case-insensitive comparison of strings (which is used heavily by the regexp
engine) was substantially refactored and optimised -- and its documentation much improved as a free bonus.
Regular expression compilation speed-up
Compiling regular expressions has been made faster when upgrading the regex to utf8 is necessary but this
isn't known when the compilation begins.
String appending is 100 times faster
When doing a lot of string appending, perls built to use the system's "malloc" could end up allocating a lot
more memory than needed in a inefficient way.
"sv_grow", the function used to allocate more memory if necessary when appending to a string, has been taught
to round up the memory it requests to a certain geometric progression, making it much faster on certain
platforms and configurations. On Win32, it's now about 100 times faster.
Eliminate "PL_*" accessor functions under ithreads
When "MULTIPLICITY" was first developed, and interpreter state moved into an interpreter struct, thread- and
interpreter-local "PL_*" variables were defined as macros that called accessor functions (returning the
disabled in Perl 5.12.0.
Now we have found another way to speed up these assignments [perl #82110].
@_ uses less memory
Previously, @_ was allocated for every subroutine at compile time with enough space for four entries. Now
this allocation is done on demand when the subroutine is called [perl #72416].
Size optimisations to SV and HV structures
"xhv_fill" has been eliminated from "struct xpvhv", saving 1 IV per hash and on some systems will cause
"struct xpvhv" to become cache-aligned. To avoid this memory saving causing a slowdown elsewhere, boolean use
of "HvFILL" now calls "HvTOTALKEYS" instead (which is equivalent), so while the fill data when actually
required are now calculated on demand, cases when this needs to be done should be rare.
The order of structure elements in SV bodies has changed. Effectively, the NV slot has swapped location with
STASH and MAGIC. As all access to SV members is via macros, this should be completely transparent. This
change allows the space saving for PVHVs documented above, and may reduce the memory allocation needed for
PVIVs on some architectures.
"XPV", "XPVIV", and "XPVNV" now allocate only the parts of the "SV" body they actually use, saving some space.
Scalars containing regular expressions now allocate only the part of the "SV" body they actually use, saving
some space.
Memory consumption improvements to Exporter
The @EXPORT_FAIL AV is no longer created unless needed, hence neither is the typeglob backing it. This saves
about 200 bytes for every package that uses Exporter but doesn't use this functionality.
Memory savings for weak references
For weak references, the common case of just a single weak reference per referent has been optimised to reduce
the storage required. In this case it saves the equivalent of one small Perl array per referent.
"%+" and "%-" use less memory
The bulk of the "Tie::Hash::NamedCapture" module used to be in the Perl core. It has now been moved to an XS
module to reduce overhead for programs that do not use "%+" or "%-".
Multiple small improvements to threads
The internal structures of threading now make fewer API calls and fewer allocations, resulting in noticeably
smaller object code. Additionally, many thread context checks have been deferred so they're done only as
needed (although this is only possible for non-debugging builds).
Adjacent pairs of nextstate opcodes are now optimized away
Previously, in code such as
use constant DEBUG => 0;
sub GAK {
warn if DEBUG;
print "stuff\n";
}
the ops for "warn if DEBUG" would be folded to a "null" op ("ex-const"), but the "nextstate" op would remain,
resulting in a runtime op dispatch of "nextstate", "nextstate", etc.
· CPAN::Meta version 2.110440 has been added as a dual-life module. It provides a standard library to read,
interpret and write CPAN distribution metadata files (like META.json and META.yml) that describe a
distribution, its contents, and the requirements for building it and installing it. The latest CPAN
distribution metadata specification is included as CPAN::Meta::Spec and notes on changes in the
specification over time are given in CPAN::Meta::History.
· HTTP::Tiny 0.012 has been added as a dual-life module. It is a very small, simple HTTP/1.1 client
designed for simple GET requests and file mirroring. It has been added so that CPAN.pm and CPANPLUS can
"bootstrap" HTTP access to CPAN using pure Perl without relying on external binaries like curl(1) or
wget(1).
· JSON::PP 2.27105 has been added as a dual-life module to allow CPAN clients to read META.json files in
CPAN distributions.
· Module::Metadata 1.000004 has been added as a dual-life module. It gathers package and POD information
from Perl module files. It is a standalone module based on Module::Build::ModuleInfo for use by other
module installation toolchain components. Module::Build::ModuleInfo has been deprecated in favor of this
module instead.
· Perl::OSType 1.002 has been added as a dual-life module. It maps Perl operating system names (like
"dragonfly" or "MSWin32") to more generic types with standardized names (like "Unix" or "Windows"). It
has been refactored out of Module::Build and ExtUtils::CBuilder and consolidates such mappings into a
single location for easier maintenance.
· The following modules were added by the Unicode::Collate upgrade. See below for details.
Unicode::Collate::CJK::Big5
Unicode::Collate::CJK::GB2312
Unicode::Collate::CJK::JISX0208
Unicode::Collate::CJK::Korean
Unicode::Collate::CJK::Pinyin
Unicode::Collate::CJK::Stroke
· Version::Requirements version 0.101020 has been added as a dual-life module. It provides a standard
library to model and manipulates module prerequisites and version constraints defined in CPAN::Meta::Spec.
Updated Modules and Pragma
· attributes has been upgraded from version 0.12 to 0.14.
· Archive::Extract has been upgraded from version 0.38 to 0.48.
Updates since 0.38 include: a safe print method that guards Archive::Extract from changes to "$\"; a fix
to the tests when run in core Perl; support for TZ files; a modification for the lzma logic to favour
IO::Uncompress::Unlzma; and a fix for an issue with NetBSD-current and its new unzip(1) executable.
· Archive::Tar has been upgraded from version 1.54 to 1.76.
Important changes since 1.54 include the following:
· pax extended headers are now skipped.
· Attribute::Handlers has been upgraded from version 0.87 to 0.89.
· autodie has been upgraded from version 2.06_01 to 2.1001.
· AutoLoader has been upgraded from version 5.70 to 5.71.
· The B module has been upgraded from version 1.23 to 1.29.
It no longer crashes when taking apart a "y///" containing characters outside the octet range or compiled
in a "use utf8" scope.
The size of the shared object has been reduced by about 40%, with no reduction in functionality.
· B::Concise has been upgraded from version 0.78 to 0.83.
B::Concise marks rv2sv(), rv2av(), and rv2hv() ops with the new "OPpDEREF" flag as "DREFed".
It no longer produces mangled output with the -tree option [perl #80632].
· B::Debug has been upgraded from version 1.12 to 1.16.
· B::Deparse has been upgraded from version 0.96 to 1.03.
The deparsing of a "nextstate" op has changed when it has both a change of package relative to the
previous nextstate, or a change of "%^H" or other state and a label. The label was previously emitted
first, but is now emitted last (5.12.1).
The "no 5.13.2" or similar form is now correctly handled by B::Deparse (5.12.3).
B::Deparse now properly handles the code that applies a conditional pattern match against implicit $_ as
it was fixed in [perl #20444].
Deparsing of "our" followed by a variable with funny characters (as permitted under the "use utf8" pragma)
has also been fixed [perl #33752].
· B::Lint has been upgraded from version 1.11_01 to 1.13.
· base has been upgraded from version 2.15 to 2.16.
· Benchmark has been upgraded from version 1.11 to 1.12.
· bignum has been upgraded from version 0.23 to 0.27.
· Carp has been upgraded from version 1.15 to 1.20.
Carp now detects incomplete caller() overrides and avoids using bogus @DB::args. To provide backtraces,
Carp relies on particular behaviour of the caller() builtin. Carp now detects if other code has
overridden this with an incomplete implementation, and modifies its backtrace accordingly. Previously
incomplete overrides would cause incorrect values in backtraces (best case), or obscure fatal errors
(worst case).
This fixes certain cases of "Bizarre copy of ARRAY" caused by modules overriding caller() incorrectly
It has been updated to use bzip2(1) 1.0.6.
· Compress::Raw::Zlib has been upgraded from version 2.024 to 2.033.
· constant has been upgraded from version 1.20 to 1.21.
Unicode constants work once more. They have been broken since Perl 5.10.0 [CPAN RT #67525].
· CPAN has been upgraded from version 1.94_56 to 1.9600.
Major highlights:
· much less configuration dialog hassle
· support for META/MYMETA.json
· support for local::lib
· support for HTTP::Tiny to reduce the dependency on FTP sites
· automatic mirror selection
· iron out all known bugs in configure_requires
· support for distributions compressed with bzip2(1)
· allow Foo/Bar.pm on the command line to mean "Foo::Bar"
· CPANPLUS has been upgraded from version 0.90 to 0.9103.
A change to cpanp-run-perl resolves RT #55964 <http://rt.cpan.org/Public/Bug/Display.html?id=55964> and RT
#57106 <http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both of which related to failures to install
distributions that use "Module::Install::DSL" (5.12.2).
A dependency on Config was not recognised as a core module dependency. This has been fixed.
CPANPLUS now includes support for META.json and MYMETA.json.
· CPANPLUS::Dist::Build has been upgraded from version 0.46 to 0.54.
· Data::Dumper has been upgraded from version 2.125 to 2.130_02.
The indentation used to be off when $Data::Dumper::Terse was set. This has been fixed [perl #73604].
This upgrade also fixes a crash when using custom sort functions that might cause the stack to change
[perl #74170].
Dumpxs no longer crashes with globs returned by *$io_ref [perl #72332].
· DB_File has been upgraded from version 1.820 to 1.821.
· DBM_Filter has been upgraded from version 0.03 to 0.04.
· Devel::DProf has been upgraded from version 20080331.00 to 20110228.00.
· diagnostics has been upgraded from version 1.19 to 1.22.
It now renders pod links slightly better, and has been taught to find descriptions for messages that share
their descriptions with other messages.
· Digest::MD5 has been upgraded from version 2.39 to 2.51.
It is now safe to use this module in combination with threads.
· Digest::SHA has been upgraded from version 5.47 to 5.61.
"shasum" now more closely mimics sha1sum(1)/md5sum(1).
"addfile" accepts all POSIX filenames.
New SHA-512/224 and SHA-512/256 transforms (ref. NIST Draft FIPS 180-4 [February 2011])
· DirHandle has been upgraded from version 1.03 to 1.04.
· Dumpvalue has been upgraded from version 1.13 to 1.16.
· DynaLoader has been upgraded from version 1.10 to 1.13.
It fixes a buffer overflow when passed a very long file name.
It no longer inherits from AutoLoader; hence it no longer produces weird error messages for unsuccessful
method calls on classes that inherit from DynaLoader [perl #84358].
· Encode has been upgraded from version 2.39 to 2.42.
Now, all 66 Unicode non-characters are treated the same way U+FFFF has always been treated: in cases when
it was disallowed, all 66 are disallowed, and in cases where it warned, all 66 warn.
· Env has been upgraded from version 1.01 to 1.02.
· Errno has been upgraded from version 1.11 to 1.13.
The implementation of Errno has been refactored to use about 55% less memory.
On some platforms with unusual header files, like Win32 gcc(1) using "mingw64" headers, some constants
that weren't actually error numbers have been exposed by Errno. This has been fixed [perl #77416].
· Exporter has been upgraded from version 5.64_01 to 5.64_03.
Exporter no longer overrides $SIG{__WARN__} [perl #74472]
· ExtUtils::CBuilder has been upgraded from version 0.27 to 0.280203.
· ExtUtils::Command has been upgraded from version 1.16 to 1.17.
· ExtUtils::Constant has been upgraded from 0.22 to 0.23.
The AUTOLOAD helper code generated by "ExtUtils::Constant::ProxySubs" can now croak() for missing
constants, or generate a complete "AUTOLOAD" subroutine in XS, allowing simplification of many modules
· Fcntl has been upgraded from version 1.06 to 1.11.
· File::Basename has been upgraded from version 2.78 to 2.82.
· File::CheckTree has been upgraded from version 4.4 to 4.41.
· File::Copy has been upgraded from version 2.17 to 2.21.
· File::DosGlob has been upgraded from version 1.01 to 1.04.
It allows patterns containing literal parentheses: they no longer need to be escaped. On Windows, it no
longer adds an extra ./ to file names returned when the pattern is a relative glob with a drive
specification, like C:*.pl [perl #71712].
· File::Fetch has been upgraded from version 0.24 to 0.32.
HTTP::Lite is now supported for the "http" scheme.
The fetch(1) utility is supported on FreeBSD, NetBSD, and Dragonfly BSD for the "http" and "ftp" schemes.
· File::Find has been upgraded from version 1.15 to 1.19.
It improves handling of backslashes on Windows, so that paths like C:\dir\/file are no longer generated
[perl #71710].
· File::Glob has been upgraded from version 1.07 to 1.12.
· File::Spec has been upgraded from version 3.31 to 3.33.
Several portability fixes were made in File::Spec::VMS: a colon is now recognized as a delimiter in native
filespecs; caret-escaped delimiters are recognized for better handling of extended filespecs; catpath()
returns an empty directory rather than the current directory if the input directory name is empty; and
abs2rel() properly handles Unix-style input (5.12.2).
· File::stat has been upgraded from 1.02 to 1.05.
The "-x" and "-X" file test operators now work correctly when run by the superuser.
· Filter::Simple has been upgraded from version 0.84 to 0.86.
· GDBM_File has been upgraded from 1.10 to 1.14.
This fixes a memory leak when DBM filters are used.
· Hash::Util has been upgraded from 0.07 to 0.11.
Hash::Util no longer emits spurious "uninitialized" warnings when recursively locking hashes that have
undefined values [perl #74280].
· Hash::Util::FieldHash has been upgraded from version 1.04 to 1.09.
· I18N::Collate has been upgraded from version 1.01 to 1.02.
classes) to be removed from an IO::Select set even if the underlying file descriptor is closed or invalid.
· IPC::Cmd has been upgraded from version 0.54 to 0.70.
Resolves an issue with splitting Win32 command lines. An argument consisting of the single character "0"
used to be omitted (CPAN RT #62961).
· IPC::Open3 has been upgraded from 1.05 to 1.09.
open3() now produces an error if the "exec" call fails, allowing this condition to be distinguished from a
child process that exited with a non-zero status [perl #72016].
The internal xclose() routine now knows how to handle file descriptors as documented, so duplicating
"STDIN" in a child process using its file descriptor now works [perl #76474].
· IPC::SysV has been upgraded from version 2.01 to 2.03.
· lib has been upgraded from version 0.62 to 0.63.
· Locale::Maketext has been upgraded from version 1.14 to 1.19.
Locale::Maketext now supports external caches.
This upgrade also fixes an infinite loop in "Locale::Maketext::Guts::_compile()" when working with tainted
values (CPAN RT #40727).
"->maketext" calls now back up and restore $@ so error messages are not suppressed (CPAN RT #34182).
· Log::Message has been upgraded from version 0.02 to 0.04.
· Log::Message::Simple has been upgraded from version 0.06 to 0.08.
· Math::BigInt has been upgraded from version 1.89_01 to 1.994.
This fixes, among other things, incorrect results when computing binomial coefficients [perl #77640].
It also prevents "sqrt($int)" from crashing under "use bigrat". [perl #73534].
· Math::BigInt::FastCalc has been upgraded from version 0.19 to 0.28.
· Math::BigRat has been upgraded from version 0.24 to 0.26_02.
· Memoize has been upgraded from version 1.01_03 to 1.02.
· MIME::Base64 has been upgraded from 3.08 to 3.13.
Includes new functions to calculate the length of encoded and decoded base64 strings.
Now provides encode_base64url() and decode_base64url() functions to process the base64 scheme for "URL
applications".
· Module::Build has been upgraded from version 0.3603 to 0.3800.
A notable change is the deprecation of several modules. Module::Build::Version has been deprecated and
VMS::Filespec, which actually is a core module as of Perl 5.8.7.
· Module::Load has been upgraded from version 0.16 to 0.18.
· Module::Load::Conditional has been upgraded from version 0.34 to 0.44.
· The mro pragma has been upgraded from version 1.02 to 1.07.
· NDBM_File has been upgraded from version 1.08 to 1.12.
This fixes a memory leak when DBM filters are used.
· Net::Ping has been upgraded from version 2.36 to 2.38.
· NEXT has been upgraded from version 0.64 to 0.65.
· Object::Accessor has been upgraded from version 0.36 to 0.38.
· ODBM_File has been upgraded from version 1.07 to 1.10.
This fixes a memory leak when DBM filters are used.
· Opcode has been upgraded from version 1.15 to 1.18.
· The overload pragma has been upgraded from 1.10 to 1.13.
"overload::Method" can now handle subroutines that are themselves blessed into overloaded classes [perl
#71998].
The documentation has greatly improved. See "Documentation" below.
· Params::Check has been upgraded from version 0.26 to 0.28.
· The parent pragma has been upgraded from version 0.223 to 0.225.
· Parse::CPAN::Meta has been upgraded from version 1.40 to 1.4401.
The latest Parse::CPAN::Meta can now read YAML and JSON files using CPAN::Meta::YAML and JSON::PP, which
are now part of the Perl core.
· PerlIO::encoding has been upgraded from version 0.12 to 0.14.
· PerlIO::scalar has been upgraded from 0.07 to 0.11.
A read() after a seek() beyond the end of the string no longer thinks it has data to read [perl #78716].
· PerlIO::via has been upgraded from version 0.09 to 0.11.
· Pod::Html has been upgraded from version 1.09 to 1.11.
· Pod::LaTeX has been upgraded from version 0.58 to 0.59.
· Pod::Perldoc has been upgraded from version 3.15_02 to 3.15_03.
regmust() no longer leaks memory.
· Safe has been upgraded from version 2.25 to 2.29.
Coderefs returned by reval() and rdo() are now wrapped via wrap_code_refs() (5.12.1).
This fixes a possible infinite loop when looking for coderefs.
It adds several "version::vxs::*" routines to the default share.
· SDBM_File has been upgraded from version 1.06 to 1.09.
· SelfLoader has been upgraded from 1.17 to 1.18.
It now works in taint mode [perl #72062].
· The sigtrap pragma has been upgraded from version 1.04 to 1.05.
It no longer tries to modify read-only arguments when generating a backtrace [perl #72340].
· Socket has been upgraded from version 1.87 to 1.94.
See "Improved IPv6 support" above.
· Storable has been upgraded from version 2.22 to 2.27.
Includes performance improvement for overloaded classes.
This adds support for serialising code references that contain UTF-8 strings correctly. The Storable
minor version number changed as a result, meaning that Storable users who set
$Storable::accept_future_minor to a "FALSE" value will see errors (see "FORWARD COMPATIBILITY" in Storable
for more details).
Freezing no longer gets confused if the Perl stack gets reallocated during freezing [perl #80074].
· Sys::Hostname has been upgraded from version 1.11 to 1.16.
· Term::ANSIColor has been upgraded from version 2.02 to 3.00.
· Term::UI has been upgraded from version 0.20 to 0.26.
· Test::Harness has been upgraded from version 3.17 to 3.23.
· Test::Simple has been upgraded from version 0.94 to 0.98.
Among many other things, subtests without a "plan" or "no_plan" now have an implicit done_testing() added
to them.
· Thread::Semaphore has been upgraded from version 2.09 to 2.12.
It provides two new methods that give more control over the decrementing of semaphores: "down_nb" and
"down_force".
· Tie::RefHash has been upgraded from version 1.38 to 1.39.
· Time::HiRes has been upgraded from version 1.9719 to 1.9721_01.
· Time::Local has been upgraded from version 1.1901_01 to 1.2000.
· Time::Piece has been upgraded from version 1.15_01 to 1.20_01.
· Unicode::Collate has been upgraded from version 0.52_01 to 0.73.
Unicode::Collate has been updated to use Unicode 6.0.0.
Unicode::Collate::Locale now supports a plethora of new locales: ar, be, bg, de__phonebook, hu, hy, kk,
mk, nso, om, tn, vi, hr, ig, ja, ko, ru, sq, se, sr, to, uk, zh, zh__big5han, zh__gb2312han, zh__pinyin,
and zh__stroke.
The following modules have been added:
Unicode::Collate::CJK::Big5 for "zh__big5han" which makes tailoring of CJK Unified Ideographs in the order
of CLDR's big5han ordering.
Unicode::Collate::CJK::GB2312 for "zh__gb2312han" which makes tailoring of CJK Unified Ideographs in the
order of CLDR's gb2312han ordering.
Unicode::Collate::CJK::JISX0208 which makes tailoring of 6355 kanji (CJK Unified Ideographs) in the JIS X
0208 order.
Unicode::Collate::CJK::Korean which makes tailoring of CJK Unified Ideographs in the order of CLDR's
Korean ordering.
Unicode::Collate::CJK::Pinyin for "zh__pinyin" which makes tailoring of CJK Unified Ideographs in the
order of CLDR's pinyin ordering.
Unicode::Collate::CJK::Stroke for "zh__stroke" which makes tailoring of CJK Unified Ideographs in the
order of CLDR's stroke ordering.
This also sees the switch from using the pure-Perl version of this module to the XS version.
· Unicode::Normalize has been upgraded from version 1.03 to 1.10.
· Unicode::UCD has been upgraded from version 0.27 to 0.32.
A new function, Unicode::UCD::num(), has been added. This function returns the numeric value of the
string passed it or "undef" if the string in its entirety has no "safe" numeric value. (For more detail,
and for the definition of "safe", see "num()" in Unicode::UCD.)
This upgrade also includes several bug fixes:
charinfo()
· It is now updated to Unicode Version 6.0.0 with Corrigendum #8, excepting that, just as with Perl
5.14, the code point at U+1F514 has no name.
· Hangul syllable code points have the correct names, and their decompositions are always output
without requiring Lingua::KO::Hangul::Util to be installed.
charblock()
This now correctly returns "No_Block" instead of "undef" for the block of a code point that hasn't
been assigned to another one.
· The version pragma has been upgraded from 0.82 to 0.88.
Because of a bug, now fixed, the is_strict() and is_lax() functions did not work when exported (5.12.1).
· The warnings pragma has been upgraded from version 1.09 to 1.12.
Calling "use warnings" without arguments is now significantly more efficient.
· The warnings::register pragma has been upgraded from version 1.01 to 1.02.
It is now possible to register warning categories other than the names of packages using
warnings::register. See perllexwarn(1) for more information.
· XSLoader has been upgraded from version 0.10 to 0.13.
· VMS::DCLsym has been upgraded from version 1.03 to 1.05.
Two bugs have been fixed [perl #84086]:
The symbol table name was lost when tying a hash, due to a thinko in "TIEHASH". The result was that all
tied hashes interacted with the local symbol table.
Unless a symbol table name had been explicitly specified in the call to the constructor, querying the
special key ":LOCAL" failed to identify objects connected to the local symbol table.
· The Win32 module has been upgraded from version 0.39 to 0.44.
This release has several new functions: Win32::GetSystemMetrics(), Win32::GetProductInfo(),
Win32::GetOSDisplayName().
The names returned by Win32::GetOSName() and Win32::GetOSDisplayName() have been corrected.
· XS::Typemap has been upgraded from version 0.03 to 0.05.
Removed Modules and Pragmata
As promised in Perl 5.12.0's release notes, the following modules have been removed from the core
distribution, and if needed should be installed from CPAN instead.
· Class::ISA has been removed from the Perl core. Prior version was 0.36.
· Pod::Plainer has been removed from the Perl core. Prior version was 1.02.
· Switch has been removed from the Perl core. Prior version was 2.16.
The removal of Shell has been deferred until after 5.14, as the implementation of Shell shipped with 5.12.0
did not correctly issue the warning that it was to be removed from core.
Documentation
New Documentation
perlgpl
perlsource, perlinterp, perlhacktut, and perlhacktips
See "perlhack and perlrepository revamp", below.
Changes to Existing Documentation
perlmodlib is now complete
The perlmodlib manpage that came with Perl 5.12.0 was missing several modules due to a bug in the script that
generates the list. This has been fixed [perl #74332] (5.12.1).
Replace incorrect tr/// table in perlebcdic
perlebcdic contains a helpful table to use in "tr///" to convert between EBCDIC and Latin1/ASCII. The table
was the inverse of the one it describes, though the code that used the table worked correctly for the specific
example given.
The table has been corrected and the sample code changed to correspond.
The table has also been changed to hex from octal, and the recipes in the pod have been altered to print out
leading zeros to make all values the same length.
Tricks for user-defined casing
perlunicode now contains an explanation of how to override, mangle and otherwise tweak the way Perl handles
upper-, lower- and other-case conversions on Unicode data, and how to provide scoped changes to alter one's
own code's behaviour without stomping on anybody else's.
INSTALL explicitly states that Perl requires a C89 compiler
This was already true, but it's now Officially Stated For The Record (5.12.2).
Explanation of "\xHH" and "\oOOO" escapes
perlop has been updated with more detailed explanation of these two character escapes.
-0NNN switch
In perlrun, the behaviour of the -0NNN switch for -0400 or higher has been clarified (5.12.2).
Maintenance policy
perlpolicy now contains the policy on what patches are acceptable for maintenance branches (5.12.1).
Deprecation policy
perlpolicy now contains the policy on compatibility and deprecation along with definitions of terms like
"deprecation" (5.12.2).
New descriptions in perldiag
The following existing diagnostics are now documented:
· Ambiguous use of %c resolved as operator %c
· Invalid version object
perlbook
perlbook has been expanded to cover many more popular books.
"SvTRUE" macro
The documentation for the "SvTRUE" macro in perlapi was simply wrong in stating that get-magic is not
processed. It has been corrected.
op manipulation functions
Several API functions that process optrees have been newly documented.
perlvar revamp
perlvar reorders the variables and groups them by topic. Each variable introduced after Perl 5.000 notes the
first version in which it is available. perlvar also has a new section for deprecated variables to note when
they were removed.
Array and hash slices in scalar context
These are now documented in perldata.
"use locale" and formats
perlform and perllocale have been corrected to state that "use locale" affects formats.
overload
overload's documentation has practically undergone a rewrite. It is now much more straightforward and clear.
perlhack and perlrepository revamp
The perlhack document is now much shorter, and focuses on the Perl 5 development process and submitting
patches to Perl. The technical content has been moved to several new documents, perlsource, perlinterp,
perlhacktut, and perlhacktips. This technical content has been only lightly edited.
The perlrepository document has been renamed to perlgit. This new document is just a how-to on using git with
the Perl source code. Any other content that used to be in perlrepository has been moved to perlhack.
Time::Piece examples
Examples in perlfaq4 have been updated to show the use of Time::Piece.
Diagnostics
The following additions or changes have been made to diagnostic output, including warnings and fatal error
messages. For the complete list of diagnostic messages, see perldiag.
New Diagnostics
New Errors
etc.
Parsing code internal error (%s)
This new fatal error is produced when parsing code supplied by an extension violates the parser's API in a
detectable way.
refcnt: fd %d%s
This new error only occurs if a internal consistency check fails when a pipe is about to be closed.
Regexp modifier "/%c" may not appear twice
The regular expression pattern has one of the mutually exclusive modifiers repeated.
Regexp modifiers "/%c" and "/%c" are mutually exclusive
The regular expression pattern has more than one of the mutually exclusive modifiers.
Using !~ with %s doesn't make sense
This error occurs when "!~" is used with "s///r" or "y///r".
New Warnings
"\b{" is deprecated; use "\b\{" instead
"\B{" is deprecated; use "\B\{" instead
Use of an unescaped "{" immediately following a "\b" or "\B" is now deprecated in order to reserve its use
for Perl itself in a future release.
Operation "%s" returns its argument for ...
Performing an operation requiring Unicode semantics (such as case-folding) on a Unicode surrogate or a
non-Unicode character now triggers this warning.
Use of qw(...) as parentheses is deprecated
See "Use of qw(...) as parentheses", above, for details.
Changes to Existing Diagnostics
· The "Variable $foo is not imported" warning that precedes a "strict 'vars'" error has now been assigned
the "misc" category, so that "no warnings" will suppress it [perl #73712].
· warn() and die() now produce "Wide character" warnings when fed a character outside the byte range if
"STDERR" is a byte-sized handle.
· The "Layer does not match this perl" error message has been replaced with these more helpful messages
[perl #73754]:
· PerlIO layer function table size (%d) does not match size expected by this perl (%d)
· PerlIO layer instance size (%d) does not match size expected by this perl (%d)
· The "Found = in conditional" warning that is emitted when a constant is assigned to a variable in a
condition is now withheld if the constant is actually a subroutine or one generated by "use constant",
since the value of the constant may not be known at the time the program is written [perl #77762].
· Previously, if none of the gethostbyaddr(), gethostbyname() and gethostent() functions were implemented on
a given platform, they would all die with the message "Unsupported socket function 'gethostent' called",
with analogous messages for getnet*() and getserv*(). This has been corrected.
· The user's address is now used as the Return-Path.
Many systems these days don't have a valid Internet domain name, and [email protected] does not accept
email with a return-path that does not resolve. So the user's address is now passed to sendmail so it's
less likely to get stuck in a mail queue somewhere [perl #82996].
· perlbug now always gives the reporter a chance to change the email address it guesses for them (5.12.2).
· perlbug should no longer warn about uninitialized values when using the -d and -v options (5.12.2).
perl5db.pl
· The remote terminal works after forking and spawns new sessions, one per forked process.
ptargrep
· ptargrep is a new utility to apply pattern matching to the contents of files in a tar archive. It comes
with "Archive::Tar".
Configuration and Compilation
See also "Naming fixes in Policy_sh.SH may invalidate Policy.sh", above.
· CCINCDIR and CCLIBDIR for the mingw64 cross-compiler are now correctly under $(CCHOME)\mingw\include and
\lib rather than immediately below $(CCHOME).
This means the "incpath", "libpth", "ldflags", "lddlflags" and "ldflags_nolargefiles" values in Config.pm
and Config_heavy.pl are now set correctly.
· "make test.valgrind" has been adjusted to account for cpan/dist/ext separation.
· On compilers that support it, -Wwrite-strings is now added to cflags by default.
· The Encode module can now (once again) be included in a static Perl build. The special-case handling for
this situation got broken in Perl 5.11.0, and has now been repaired.
· The previous default size of a PerlIO buffer (4096 bytes) has been increased to the larger of 8192 bytes
and your local BUFSIZ. Benchmarks show that doubling this decade-old default increases read and write
performance by around 25% to 50% when using the default layers of perlio on top of unix. To choose a non-
default size, such as to get back the old value or to obtain an even larger value, configure with:
./Configure -Accflags=-DPERLIOBUF_DEFAULT_BUFSIZ=N
where N is the desired size in bytes; it should probably be a multiple of your page size.
· An "incompatible operand types" error in ternary expressions when building with "clang" has been fixed
(5.12.2).
· Perl now skips setuid File::Copy tests on partitions it detects mounted as "nosuid" (5.12.2).
Platform Support
New Platforms
AIX Perl now builds on AIX 4.2 (5.12.1).
· README.aix has been updated with information about the XL C/C++ V11 compiler suite (5.12.2).
ARM
· The "d_u32align" configuration probe on ARM has been fixed (5.12.2).
Cygwin
· MakeMaker has been updated to build manpages on cygwin.
· Improved rebase behaviour
If a DLL is updated on cygwin the old imagebase address is reused. This solves most rebase errors,
especially when updating on core DLL's. See
http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README
<http://www.tishler.net/jason/software/rebase/rebase-2.4.2.README> for more information.
· Support for the standard cygwin dll prefix (needed for FFIs)
· Updated build hints file
FreeBSD 7
· FreeBSD 7 no longer contains /usr/bin/objformat. At build time, Perl now skips the objformat check for
versions 7 and higher and assumes ELF (5.12.1).
HP-UX
· Perl now allows -Duse64bitint without promoting to "use64bitall" on HP-UX (5.12.1).
IRIX
· Conversion of strings to floating-point numbers is now more accurate on IRIX systems [perl #32380].
Mac OS X
· Early versions of Mac OS X (Darwin) had buggy implementations of the setregid(), setreuid(), setrgid(,)
and setruid() functions, so Perl would pretend they did not exist.
These functions are now recognised on Mac OS 10.5 (Leopard; Darwin 9) and higher, as they have been fixed
[perl #72990].
MirBSD
· Previously if you built Perl with a shared libperl.so on MirBSD (the default config), it would work up to
the installation; however, once installed, it would be unable to find libperl. Path handling is now
treated as in the other BSD dialects.
NetBSD
· The NetBSD hints file has been changed to make the system malloc the default.
OpenBSD
VMS
· Extension building on older (pre 7.3-2) VMS systems was broken because configure.com hit the DCL symbol
length limit of 1K. We now work within this limit when assembling the list of extensions in the core
build (5.12.1).
· We fixed configuring and building Perl with -Uuseperlio (5.12.1).
· "PerlIOUnix_open" now honours the default permissions on VMS.
When "perlio" became the default and "unix" became the default bottom layer, the most common path for
creating files from Perl became "PerlIOUnix_open", which has always explicitly used 0666 as the permission
mask. This prevents inheriting permissions from RMS defaults and ACLs, so to avoid that problem, we now
pass 0777 to open(). In the VMS CRTL, 0777 has a special meaning over and above intersecting with the
current umask; specifically, it allows Unix syscalls to preserve native default permissions (5.12.3).
· The shortening of symbols longer than 31 characters in the core C sources and in extensions is now by
default done by the C compiler rather than by xsubpp (which could only do so for generated symbols in XS
code). You can reenable xsubpp's symbol shortening by configuring with -Uuseshortenedsymbols, but you'll
have some work to do to get the core sources to compile.
· Record-oriented files (record format variable or variable with fixed control) opened for write by the
"perlio" layer will now be line-buffered to prevent the introduction of spurious line breaks whenever the
perlio buffer fills up.
· git_version.h is now installed on VMS. This was an oversight in v5.12.0 which caused some extensions to
fail to build (5.12.2).
· Several memory leaks in stat() have been fixed (5.12.2).
· A memory leak in Perl_rename() due to a double allocation has been fixed (5.12.2).
· A memory leak in vms_fid_to_name() (used by realpath() and realname()> has been fixed (5.12.2).
Windows
See also "fork() emulation will not wait for signalled children" and "Perl source code is read in text mode on
Windows", above.
· Fixed build process for SDK2003SP1 compilers.
· Compilation with Visual Studio 2010 is now supported.
· When using old 32-bit compilers, the define "_USE_32BIT_TIME_T" is now set in $Config{ccflags}. This
improves portability when compiling XS extensions using new compilers, but for a Perl compiled with old
32-bit compilers.
· $Config{gccversion} is now set correctly when Perl is built using the mingw64 compiler from
<http://mingw64.org> [perl #73754].
· When building Perl with the mingw64 x64 cross-compiler "incpath", "libpth", "ldflags", "lddlflags" and
"ldflags_nolargefiles" values in Config.pm and Config_heavy.pl were not previously being set correctly
because, with that compiler, the include and lib directories are not immediately below "$(CCHOME)"
Internal Changes
New APIs
CLONE_PARAMS structure added to ease correct thread creation
Modules that create threads should now create "CLONE_PARAMS" structures by calling the new function
Perl_clone_params_new(), and free them with Perl_clone_params_del(). This will ensure compatibility with any
future changes to the internals of the "CLONE_PARAMS" structure layout, and that it is correctly allocated and
initialised.
New parsing functions
Several functions have been added for parsing Perl statements and expressions. These functions are meant to
be used by XS code invoked during Perl parsing, in a recursive-descent manner, to allow modules to augment the
standard Perl syntax.
· parse_stmtseq() parses a sequence of statements, up to closing brace or EOF.
· parse_fullstmt() parses a complete Perl statement, including optional label.
· parse_barestmt() parses a statement without a label.
· parse_block() parses a code block.
· parse_label() parses a statement label, separate from statements.
· "parse_fullexpr()", "parse_listexpr()", "parse_termexpr()", and "parse_arithexpr()" parse expressions at
various precedence levels.
Hints hash API
A new C API for introspecting the hinthash "%^H" at runtime has been added. See "cop_hints_2hv",
"cop_hints_fetchpvn", "cop_hints_fetchpvs", "cop_hints_fetchsv", and "hv_copy_hints_hv" in perlapi for
details.
A new, experimental API has been added for accessing the internal structure that Perl uses for "%^H". See the
functions beginning with "cophh_" in perlapi.
C interface to caller()
The "caller_cx" function has been added as an XSUB-writer's equivalent of caller(). See perlapi for details.
Custom per-subroutine check hooks
XS code in an extension module can now annotate a subroutine (whether implemented in XS or in Perl) so that
nominated XS code will be called at compile time (specifically as part of op checking) to change the op tree
of that subroutine. The compile-time check function (supplied by the extension module) can implement argument
processing that can't be expressed as a prototype, generate customised compile-time warnings, perform constant
folding for a pure function, inline a subroutine consisting of sufficiently simple ops, replace the whole call
with a custom op, and so on. This was previously all possible by hooking the "entersub" op checker, but the
new mechanism makes it easy to tie the hook to a specific subroutine. See "cv_set_call_checker" in perlapi.
To help in writing custom check hooks, several subtasks within standard "entersub" op checking have been
separated out and exposed in the API.
The old "PL_custom_op_names"/"PL_custom_op_descs" interface is still supported but discouraged.
Scope hooks
It is now possible for XS code to hook into Perl's lexical scope mechanism at compile time, using the new
"Perl_blockhook_register" function. See "Compile-time scope hooks" in perlguts.
The recursive part of the peephole optimizer is now hookable
In addition to "PL_peepp", for hooking into the toplevel peephole optimizer, a "PL_rpeepp" is now available to
hook into the optimizer recursing into side-chains of the optree.
New non-magical variants of existing functions
The following functions/macros have been added to the API. The *_nomg macros are equivalent to their
non-"_nomg" variants, except that they ignore get-magic. Those ending in "_flags" allow one to specify
whether get-magic is processed.
sv_2bool_flags
SvTRUE_nomg
sv_2nv_flags
SvNV_nomg
sv_cmp_flags
sv_cmp_locale_flags
sv_eq_flags
sv_collxfrm_flags
In some of these cases, the non-"_flags" functions have been replaced with wrappers around the new functions.
pv/pvs/sv versions of existing functions
Many functions ending with pvn now have equivalent "pv/pvs/sv" versions.
List op-building functions
List op-building functions have been added to the API. See op_append_elem, op_append_list, and
op_prepend_elem in perlapi.
"LINKLIST"
The LINKLIST macro, part of op building that constructs the execution-order op chain, has been added to the
API.
Localisation functions
The "save_freeop", "save_op", "save_pushi32ptr" and "save_pushptrptr" functions have been added to the API.
Stash names
A stash can now have a list of effective names in addition to its usual name. The first effective name can be
accessed via the "HvENAME" macro, which is now the recommended name to use in MRO linearisations ("HvNAME"
being a fallback if there is no "HvENAME").
These names are added and deleted via "hv_ename_add" and "hv_ename_delete". These two functions are not part
This function returns the SV representing $_, whether it's lexical or dynamic.
"Perl_croak_no_modify"
Perl_croak_no_modify() is short-hand for "Perl_croak("%s", PL_no_modify)".
"PERL_STATIC_INLINE" define
The "PERL_STATIC_INLINE" define has been added to provide the best-guess incantation to use for static inline
functions, if the C compiler supports C99-style static inline. If it doesn't, it'll give a plain "static".
"HAS_STATIC_INLINE" can be used to check if the compiler actually supports inline functions.
New "pv_escape" option for hexadecimal escapes
A new option, "PERL_PV_ESCAPE_NONASCII", has been added to "pv_escape" to dump all characters above ASCII in
hexadecimal. Before, one could get all characters as hexadecimal or the Latin1 non-ASCII as octal.
"lex_start"
"lex_start" has been added to the API, but is considered experimental.
op_scope() and op_lvalue()
The op_scope() and op_lvalue() functions have been added to the API, but are considered experimental.
C API Changes
"PERL_POLLUTE" has been removed
The option to define "PERL_POLLUTE" to expose older 5.005 symbols for backwards compatibility has been
removed. Its use was always discouraged, and MakeMaker contains a more specific escape hatch:
perl Makefile.PL POLLUTE=1
This can be used for modules that have not been upgraded to 5.6 naming conventions (and really should be
completely obsolete by now).
Check API compatibility when loading XS modules
When Perl's API changes in incompatible ways (which usually happens between major releases), XS modules
compiled for previous versions of Perl will no longer work. They need to be recompiled against the new Perl.
The "XS_APIVERSION_BOOTCHECK" macro has been added to ensure that modules are recompiled and to prevent users
from accidentally loading modules compiled for old perls into newer perls. That macro, which is called when
loading every newly compiled extension, compares the API version of the running perl with the version a module
has been compiled for and raises an exception if they don't match.
Perl_fetch_cop_label
The first argument of the C API function "Perl_fetch_cop_label" has changed from "struct refcounted_he *" to
"COP *", to insulate the user from implementation details.
This API function was marked as "may change", and likely isn't in use outside the core. (Neither an unpacked
CPAN nor Google's codesearch finds any other references to it.)
"CvGV_set(cv,gv)" has been introduced to run this operation safely. Note that modification of this field is
not part of the public API, regardless of this new macro (and despite its being listed in this section).
CvSTASH() is no longer an lvalue
The CvSTASH() macro can now only be used as an rvalue. CvSTASH_set() has been added to replace assignment to
CvSTASH(). This is to ensure that backreferences are handled properly. These macros are not part of the API.
Calling conventions for "newFOROP" and "newWHILEOP"
The way the parser handles labels has been cleaned up and refactored. As a result, the newFOROP() constructor
function no longer takes a parameter stating what label is to go in the state op.
The newWHILEOP() and newFOROP() functions no longer accept a line number as a parameter.
Flags passed to "uvuni_to_utf8_flags" and "utf8n_to_uvuni"
Some of the flags parameters to uvuni_to_utf8_flags() and utf8n_to_uvuni() have changed. This is a result of
Perl's now allowing internal storage and manipulation of code points that are problematic in some situations.
Hence, the default actions for these functions has been complemented to allow these code points. The new
flags are documented in perlapi. Code that requires the problematic code points to be rejected needs to
change to use the new flags. Some flag names are retained for backward source compatibility, though they do
nothing, as they are now the default. However the flags "UNICODE_ALLOW_FDD0", "UNICODE_ALLOW_FFFF",
"UNICODE_ILLEGAL", and "UNICODE_IS_ILLEGAL" have been removed, as they stem from a fundamentally broken model
of how the Unicode non-character code points should be handled, which is now described in "Non-character code
points" in perlunicode. See also the Unicode section under "Selected Bug Fixes".
Deprecated C APIs
"Perl_ptr_table_clear"
"Perl_ptr_table_clear" is no longer part of Perl's public API. Calling it now generates a deprecation
warning, and it will be removed in a future release.
"sv_compile_2op"
The sv_compile_2op() API function is now deprecated. Searches suggest that nothing on CPAN is using it,
so this should have zero impact.
It attempted to provide an API to compile code down to an optree, but failed to bind correctly to lexicals
in the enclosing scope. It's not possible to fix this problem within the constraints of its parameters
and return value.
"find_rundefsvoffset"
The "find_rundefsvoffset" function has been deprecated. It appeared that its design was insufficient for
reliably getting the lexical $_ at run-time.
Use the new "find_rundefsv" function or the "UNDERBAR" macro instead. They directly return the right SV
representing $_, whether it's lexical or dynamic.
"CALL_FPTR" and "CPERLscope"
Those are left from an old implementation of "MULTIPLICITY" using C++ objects, which was removed in Perl
5.8. Nowadays these macros do exactly nothing, so they shouldn't be used anymore.
For compatibility, they are still defined for external "XS" code. Only extensions defining "PERL_CORE"
must be updated now.
10%. In particular, the memory used by the scope stack to record each active lexical variable has been
halved.
Memory allocation for pointer tables
Memory allocation for pointer tables has been changed. Previously "Perl_ptr_table_store" allocated memory
from the same arena system as "SV" bodies and "HE"s, with freed memory remaining bound to those arenas until
interpreter exit. Now it allocates memory from arenas private to the specific pointer table, and that memory
is returned to the system when "Perl_ptr_table_free" is called. Additionally, allocation and release are both
less CPU intensive.
"UNDERBAR"
The "UNDERBAR" macro now calls "find_rundefsv". "dUNDERBAR" is now a noop but should still be used to ensure
past and future compatibility.
String comparison routines renamed
The "ibcmp_*" functions have been renamed and are now called "foldEQ", "foldEQ_locale", and "foldEQ_utf8".
The old names are still available as macros.
"chop" and "chomp" implementations merged
The opcode bodies for "chop" and "chomp" and for "schop" and "schomp" have been merged. The implementation
functions Perl_do_chop() and Perl_do_chomp(), never part of the public API, have been merged and moved to a
static function in pp.c. This shrinks the Perl binary slightly, and should not affect any code outside the
core (unless it is relying on the order of side-effects when "chomp" is passed a list of values).
Selected Bug Fixes
I/O
· Perl no longer produces this warning:
$ perl -we 'open(my $f, ">", \my $x); binmode($f, "scalar")'
Use of uninitialized value in binmode at -e line 1.
· Opening a glob reference via "open($fh, ">", \*glob)" no longer causes the glob to be corrupted when the
filehandle is printed to. This would cause Perl to crash whenever the glob's contents were accessed [perl
#77492].
· PerlIO no longer crashes when called recursively, such as from a signal handler. Now it just leaks memory
[perl #75556].
· Most I/O functions were not warning for unopened handles unless the "closed" and "unopened" warnings
categories were both enabled. Now only "use warnings 'unopened'" is necessary to trigger these warnings,
as had always been the intention.
· There have been several fixes to PerlIO layers:
When "binmode(FH, ":crlf")" pushes the ":crlf" layer on top of the stack, it no longer enables crlf layers
lower in the stack so as to avoid unexpected results [perl #38456].
Opening a file in ":raw" mode now does what it advertises to do (first open the file, then "binmode" it),
instead of simply leaving off the top layer [perl #80764].
· Syntax errors in "(?{...})" blocks no longer cause panic messages [perl #2353].
· A pattern like "(?:(o){2})?" no longer causes a "panic" error [perl #39233].
· A fatal error in regular expressions containing "(.*?)" when processing UTF-8 data has been fixed [perl
#75680] (5.12.2).
· An erroneous regular expression engine optimisation that caused regex verbs like *COMMIT sometimes to be
ignored has been removed.
· The regular expression bracketed character class "[\8\9]" was effectively the same as "[89\000]",
incorrectly matching a NULL character. It also gave incorrect warnings that the 8 and 9 were ignored.
Now "[\8\9]" is the same as "[89]" and gives legitimate warnings that "\8" and "\9" are unrecognized
escape sequences, passed-through.
· A regular expression match in the right-hand side of a global substitution ("s///g") that is in the same
scope will no longer cause match variables to have the wrong values on subsequent iterations. This can
happen when an array or hash subscript is interpolated in the right-hand side, as in "s|(.)|@a{ print($1),
/./ }|g" [perl #19078].
· Several cases in which characters in the Latin-1 non-ASCII range (0x80 to 0xFF) used not to match
themselves, or used to match both a character class and its complement, have been fixed. For instance,
U+00E2 could match both "\w" and "\W" [perl #78464] [perl #18281] [perl #60156].
· Matching a Unicode character against an alternation containing characters that happened to match
continuation bytes in the former's UTF8 representation (like "qq{\x{30ab}} =~ /\xab|\xa9/") would cause
erroneous warnings [perl #70998].
· The trie optimisation was not taking empty groups into account, preventing "foo" from matching
"/\A(?:(?:)foo|bar|zot)\z/" [perl #78356].
· A pattern containing a "+" inside a lookahead would sometimes cause an incorrect match failure in a global
match (for example, "/(?=(\S+))/g") [perl #68564].
· A regular expression optimisation would sometimes cause a match with a "{n,m}" quantifier to fail when it
should have matched [perl #79152].
· Case-insensitive matching in regular expressions compiled under "use locale" now works much more sanely
when the pattern or target string is internally encoded in UTF8. Previously, under these conditions the
localeness was completely lost. Now, code points above 255 are treated as Unicode, but code points
between 0 and 255 are treated using the current locale rules, regardless of whether the pattern or the
string is encoded in UTF8. The few case-insensitive matches that cross the 255/256 boundary are not
allowed. For example, 0xFF does not caselessly match the character at 0x178, LATIN CAPITAL LETTER Y WITH
DIAERESIS, because 0xFF may not be LATIN SMALL LETTER Y in the current locale, and Perl has no way of
knowing if that character even exists in the locale, much less what code point it is.
· The "(?|...)" regular expression construct no longer crashes if the final branch has more sets of
capturing parentheses than any other branch. This was fixed in Perl 5.10.1 for the case of a single
branch, but that fix did not take multiple branches into account [perl #84746].
· A bug has been fixed in the implementation of "{...}" quantifiers in regular expressions that prevented
the code block in "/((\w+)(?{ print $2 })){2}/" from seeing the $2 sometimes [perl #84294].
· A regression introduced in Perl 5.12.0, making "my $x = 3; $x = length(undef)" result in $x set to 3 has
been fixed. $x will now be "undef" [perl #85508] (5.12.2).
· When strict "refs" mode is off, "%{...}" in rvalue context returns "undef" if its argument is undefined.
An optimisation introduced in Perl 5.12.0 to make "keys %{...}" faster when used as a boolean did not take
this into account, causing "keys %{+undef}" (and "keys %$foo" when $foo is undefined) to be an error,
which it should be so in strict mode only [perl #81750].
· Constant-folding used to cause
$text =~ ( 1 ? /phoo/ : /bear/)
to turn into
$text =~ /phoo/
at compile time. Now it correctly matches against $_ [perl #20444].
· Parsing Perl code (either with string "eval" or by loading modules) from within a "UNITCHECK" block no
longer causes the interpreter to crash [perl #70614].
· String "eval"s no longer fail after 2 billion scopes have been compiled [perl #83364].
· The parser no longer hangs when encountering certain Unicode characters, such as U+387 [perl #74022].
· Defining a constant with the same name as one of Perl's special blocks (like "INIT") stopped working in
5.12.0, but has now been fixed [perl #78634].
· A reference to a literal value used as a hash key ($hash{\"foo"}) used to be stringified, even if the hash
was tied [perl #79178].
· A closure containing an "if" statement followed by a constant or variable is no longer treated as a
constant [perl #63540].
· "state" can now be used with attributes. It used to mean the same thing as "my" if any attributes were
present [perl #68658].
· Expressions like "@$a > 3" no longer cause $a to be mentioned in the "Use of uninitialized value in
numeric gt" warning when $a is undefined (since it is not part of the ">" expression, but the operand of
the "@") [perl #72090].
· Accessing an element of a package array with a hard-coded number (as opposed to an arbitrary expression)
would crash if the array did not exist. Usually the array would be autovivified during compilation, but
typeglob manipulation could remove it, as in these two cases which used to crash:
*d = *a; print $d[0];
undef *d; print $d[0];
· The -C command-line option, when used on the shebang line, can now be followed by other options [perl
#72434].
· The "B" module was returning "B::OP"s instead of "B::LOGOP"s for "entertry" [perl #80622]. This was due
to a bug in the Perl core, not in "B" itself.
Undefining the glob containing a package ("undef *Foo::")
Undefining an ISA glob ("undef *Foo::ISA")
Deleting an ISA stash element ("delete $Foo::{ISA}")
Sharing @ISA arrays between classes (via "*Foo::ISA = \@Bar::ISA" or "*Foo::ISA = *Bar::ISA") [perl
#77238]
"undef *Foo::ISA" would even stop a new @Foo::ISA array from updating caches.
· Typeglob assignments would crash if the glob's stash no longer existed, so long as the glob assigned to
were named "ISA" or the glob on either side of the assignment contained a subroutine.
· "PL_isarev", which is accessible to Perl via "mro::get_isarev" is now updated properly when packages are
deleted or removed from the @ISA of other classes. This allows many packages to be created and deleted
without causing a memory leak [perl #75176].
In addition, various other bugs related to typeglobs and stashes have been fixed:
· Some work has been done on the internal pointers that link between symbol tables (stashes), typeglobs, and
subroutines. This has the effect that various edge cases related to deleting stashes or stash entries
(for example, <%FOO:: = ()>), and complex typeglob or code-reference aliasing, will no longer crash the
interpreter.
· Assigning a reference to a glob copy now assigns to a glob slot instead of overwriting the glob with a
scalar [perl #1804] [perl #77508].
· A bug when replacing the glob of a loop variable within the loop has been fixed [perl #21469]. This means
the following code will no longer crash:
for $x (...) {
*x = *y;
}
· Assigning a glob to a PVLV used to convert it to a plain string. Now it works correctly, and a PVLV can
hold a glob. This would happen when a nonexistent hash or array element was passed to a subroutine:
sub { $_[0] = *foo }->($hash{key});
# $_[0] would have been the string "*main::foo"
It also happened when a glob was assigned to, or returned from, an element of a tied array or hash [perl
#36051].
· When trying to report "Use of uninitialized value $Foo::BAR", crashes could occur if the glob holding the
global variable in question had been detached from its original stash by, for example, "delete
$::{"Foo::"}". This has been fixed by disabling the reporting of variable names in those cases.
· During the restoration of a localised typeglob on scope exit, any destructors called as a result would be
able to see the typeglob in an inconsistent state, containing freed entries, which could result in a
crash. This would affect code like this:
local *@;
eval { die bless [] }; # puts an object in $@
sub DESTROY {
local $@; # boom
}
· Subroutines and package variables inside a package whose name ends with "::" can now be accessed with a
fully qualified name.
Unicode
· What has become known as "the Unicode Bug" is almost completely resolved in this release. Under "use
feature 'unicode_strings'" (which is automatically selected by "use 5.012" and above), the internal
storage format of a string no longer affects the external semantics. [perl #58182].
There are two known exceptions:
1. The now-deprecated, user-defined case-changing functions require utf8-encoded strings to operate. The
CPAN module Unicode::Casing has been written to replace this feature without its drawbacks, and the
feature is scheduled to be removed in 5.16.
2. quotemeta() (and its in-line equivalent "\Q") can also give different results depending on whether a
string is encoded in UTF-8. See "The "Unicode Bug"" in perlunicode.
· Handling of Unicode non-character code points has changed. Previously they were mostly considered
illegal, except that in some place only one of the 66 of them was known. The Unicode Standard considers
them all legal, but forbids their "open interchange". This is part of the change to allow internal use of
any code point (see "Core Enhancements"). Together, these changes resolve [perl #38722], [perl #51918],
[perl #51936], and [perl #63446].
· Case-insensitive "/i" regular expression matching of Unicode characters that match multiple characters now
works much more as intended. For example
"\N{LATIN SMALL LIGATURE FFI}" =~ /ffi/ui
and
"ffi" =~ /\N{LATIN SMALL LIGATURE FFI}/ui
are both true. Previously, there were many bugs with this feature. What hasn't been fixed are the places
where the pattern contains the multiple characters, but the characters are split up by other things, such
as in
"\N{LATIN SMALL LIGATURE FFI}" =~ /(f)(f)i/ui
or
"\N{LATIN SMALL LIGATURE FFI}" =~ /ffi*/ui
or
"\N{LATIN SMALL LIGATURE FFI}" =~ /[a-f][f-m][g-z]/ui
None of these match.
Also, this matching doesn't fully conform to the current Unicode Standard, which asks that the matching be
made upon the NFD (Normalization Form Decomposed) of the text. However, as of this writing (April 2010),
the Unicode Standard is currently in flux about what they will recommend doing with regard in such
scenarios. It may be that they will throw out the whole concept of multi-character matches. [perl
#71736].
· Sometimes the UTF8 length cache would not be reset on a value returned by substr, causing
"length(substr($uni_string, ...))" to give wrong answers. With "${^UTF8CACHE}" set to -1, it would also
produce a "panic" error message [perl #77692].
Ties, Overloading and Other Magic
· Overloading now works properly in conjunction with tied variables. What formerly happened was that most
ops checked their arguments for overloading before checking for magic, so for example an overloaded object
returned by a tied array access would usually be treated as not overloaded [RT #57012].
· Various instances of magic (like tie methods) being called on tied variables too many or too few times
have been fixed:
· "$tied->()" did not always call FETCH [perl #8438].
· Filetest operators and "y///" and "tr///" were calling FETCH too many times.
· The "=" operator used to ignore magic on its right-hand side if the scalar happened to hold a typeglob
(if a typeglob was the last thing returned from or assigned to a tied scalar) [perl #77498].
· Dereference operators used to ignore magic if the argument was a reference already (such as from a
previous FETCH) [perl #72144].
· "splice" now calls set-magic (so changes made by "splice @ISA" are respected by method calls) [perl
#78400].
· In-memory files created by "open($fh, ">", \$buffer)" were not calling FETCH/STORE at all [perl
#43789] (5.12.2).
· utf8::is_utf8() now respects get-magic (like $1) (5.12.1).
· Non-commutative binary operators used to swap their operands if the same tied scalar was used for both
operands and returned a different value for each FETCH. For instance, if $t returned 2 the first time and
3 the second, then "$t/$t" would evaluate to 1.5. This has been fixed [perl #87708].
· String "eval" now detects taintedness of overloaded or tied arguments [perl #75716].
· String "eval" and regular expression matches against objects with string overloading no longer cause
memory corruption or crashes [perl #77084].
· readline now honors "<>" overloading on tied arguments.
· "<expr>" always respects overloading now if the expression is overloaded.
Because "<> as glob" was parsed differently from "<> as filehandle" from 5.6 onwards, something like
"<$foo[0]>" did not handle overloading, even if $foo[0] was an overloaded object. This was contrary to
the documentation for overload, and meant that "<>" could not be used as a general overloaded iterator
operator.
· The fallback behaviour of overloading on binary operators was asymmetric [perl #71286].
· Magic applied to variables in the main package no longer affects other packages. See "Magic variables
outside the main package" above [perl #76138].
· Sometimes magic (ties, taintedness, etc.) attached to variables could cause an object to last longer than
expressions, but not for simple scalars [perl #82250].
· "lc", "uc", "lcfirst", and "ucfirst" no longer return untainted strings when the argument is tainted.
This has been broken since perl 5.8.9 [perl #87336].
The Debugger
· The Perl debugger now also works in taint mode [perl #76872].
· Subroutine redefinition works once more in the debugger [perl #48332].
· When -d is used on the shebang ("#!") line, the debugger now has access to the lines of the main program.
In the past, this sometimes worked and sometimes did not, depending on the order in which things happened
to be arranged in memory [perl #71806].
· A possible memory leak when using caller() to set @DB::args has been fixed (5.12.2).
· Perl no longer stomps on $DB::single, $DB::trace, and $DB::signal if these variables already have values
when $^P is assigned to [perl #72422].
· "#line" directives in string evals were not properly updating the arrays of lines of code ("@{"_< ..."}")
that the debugger (or any debugging or profiling module) uses. In threaded builds, they were not being
updated at all. In non-threaded builds, the line number was ignored, so any change to the existing line
number would cause the lines to be misnumbered [perl #79442].
Threads
· Perl no longer accidentally clones lexicals in scope within active stack frames in the parent when
creating a child thread [perl #73086].
· Several memory leaks in cloning and freeing threaded Perl interpreters have been fixed [perl #77352].
· Creating a new thread when directory handles were open used to cause a crash, because the handles were not
cloned, but simply passed to the new thread, resulting in a double free.
Now directory handles are cloned properly on Windows and on systems that have a "fchdir" function. On
other systems, new threads simply do not inherit directory handles from their parent threads [perl
#75154].
· The typeglob "*,", which holds the scalar variable $, (output field separator), had the wrong reference
count in child threads.
· [perl #78494] When pipes are shared between threads, the "close" function (and any implicit close, such as
on thread exit) no longer blocks.
· Perl now does a timely cleanup of SVs that are cloned into a new thread but then discovered to be orphaned
(that is, their owners are not cloned). This eliminates several "scalars leaked" warnings when joining
threads.
Scoping and Subroutines
· Lvalue subroutines are again able to return copy-on-write scalars. This had been broken since version
5.10.0 [perl #75656] (5.12.3).
· "require" no longer causes "caller" to return the wrong file name for the scope that called "require" and
other scopes higher up that had the same file name [perl #68712].
· Mentioning a read-only lexical variable from the enclosing scope in a string "eval" no longer causes the
variable to become writable [perl #19135].
Signals
· Within signal handlers, $! is now implicitly localized.
· CHLD signals are no longer unblocked after a signal handler is called if they were blocked before by
"POSIX::sigprocmask" [perl #82040].
· A signal handler called within a signal handler could cause leaks or double-frees. Now fixed [perl
#76248].
Miscellaneous Memory Leaks
· Several memory leaks when loading XS modules were fixed (5.12.2).
· substr(), pos(), keys(), and vec() could, when used in combination with lvalues, result in leaking the
scalar value they operate on, and cause its destruction to happen too late. This has now been fixed.
· The postincrement and postdecrement operators, "++" and "--", used to cause leaks when used on references.
This has now been fixed.
· Nested "map" and "grep" blocks no longer leak memory when processing large lists [perl #48004].
· "use VERSION" and "no VERSION" no longer leak memory [perl #78436] [perl #69050].
· ".=" followed by "<>" or "readline" would leak memory if $/ contained characters beyond the octet range
and the scalar assigned to happened to be encoded as UTF8 internally [perl #72246].
· "eval 'BEGIN{die}'" no longer leaks memory on non-threaded builds.
Memory Corruption and Crashes
· glob() no longer crashes when %File::Glob:: is empty and "CORE::GLOBAL::glob" isn't present [perl #75464]
(5.12.2).
· readline() has been fixed when interrupted by signals so it no longer returns the "same thing" as before
or random memory.
· When assigning a list with duplicated keys to a hash, the assignment used to return garbage and/or freed
values:
@a = %h = (list with some duplicate keys);
This has now been fixed [perl #31865].
· The mechanism for freeing objects in globs used to leave dangling pointers to freed SVs, meaning Perl
users could see corrupted state during destruction.
Perl now frees only the affected slots of the GV, rather than freeing the GV itself. This makes sure that
there are no dangling refs or corrupted state during destruction.
· The interpreter no longer crashes when freeing deeply-nested arrays of arrays. Hashes have not been fixed
yet [perl #44225].
· Concatenating long strings under "use encoding" no longer causes Perl to crash [perl #78674].
· A bug in how we process filetest operations could cause a segfault. Filetests don't always expect an op
on the stack, so we now use TOPs only if we're sure that we're not "stat"ing the "_" filehandle. This is
indicated by "OPf_KIDS" (as checked in ck_ftst) [perl #74542] (5.12.1).
· unpack() now handles scalar context correctly for %32H and %32u, fixing a potential crash. split() would
crash because the third item on the stack wasn't the regular expression it expected. "unpack("%2H", ...)"
would return both the unpacked result and the checksum on the stack, as would "unpack("%2u", ...)" [perl
#73814] (5.12.2).
Fixes to Various Perl Operators
· The "&", "|", and "^" bitwise operators no longer coerce read-only arguments [perl #20661].
· Stringifying a scalar containing "-0.0" no longer has the effect of turning false into true [perl #45133].
· Some numeric operators were converting integers to floating point, resulting in loss of precision on
64-bit platforms [perl #77456].
· sprintf() was ignoring locales when called with constant arguments [perl #78632].
· Combining the vector (%v) flag and dynamic precision would cause "sprintf" to confuse the order of its
arguments, making it treat the string as the precision and vice-versa [perl #83194].
Bugs Relating to the C API
· The C-level "lex_stuff_pvn" function would sometimes cause a spurious syntax error on the last line of the
file if it lacked a final semicolon [perl #74006] (5.12.1).
· The "eval_sv" and "eval_pv" C functions now set $@ correctly when there is a syntax error and no
"G_KEEPERR" flag, and never set it if the "G_KEEPERR" flag is present [perl #3719].
· The XS multicall API no longer causes subroutines to lose reference counts if called via the multicall
interface from within those very subroutines. This affects modules like List::Util. Calling one of its
functions with an active subroutine as the first argument could cause a crash [perl #78070].
· The "SvPVbyte" function available to XS modules now calls magic before downgrading the SV, to avoid
warnings about wide characters [perl #72398].
· The ref types in the typemap for XS bindings now support magical variables [perl #72684].
· "sv_catsv_flags" no longer calls "mg_get" on its second argument (the source string) if the flags passed
to it do not include SV_GMAGIC. So it now matches the documentation.
· "my_strftime" no longer leaks memory. This fixes a memory leak in "POSIX::strftime" [perl #73520].
· XSUB.h now correctly redefines fgets under PERL_IMPLICIT_SYS [perl #55049] (5.12.1).
· XS code using fputc() or fputs() on Windows could cause an error due to their arguments being swapped
[perl #72704] (5.12.1).
· A possible segfault in the "T_PTROBJ" default typemap has been fixed (5.12.2).
· A bug that could cause "Unknown error" messages when "call_sv(code, G_EVAL)" is called from an XS
destructor has been fixed (5.12.2).
See also: <http://rt.perl.org/rt3/Public/Bug/Display.html?id=67694>
· readline() returns an empty string instead of a cached previous value when it is interrupted by a signal
· The changes in prototype handling break Switch. A patch has been sent upstream and will hopefully appear
on CPAN soon.
· The upgrade to ExtUtils-MakeMaker-6.57_05 has caused some tests in the Module-Install distribution on CPAN
to fail. (Specifically, 02_mymeta.t tests 5 and 21; 18_all_from.t tests 6 and 15; 19_authors.t tests 5,
13, 21, and 29; and 20_authors_with_special_characters.t tests 6, 15, and 23 in version 1.00 of that
distribution now fail.)
· On VMS, "Time::HiRes" tests will fail due to a bug in the CRTL's implementation of "setitimer": previous
timer values would be cleared if a timer expired but not if the timer was reset before expiring. HP
OpenVMS Engineering have corrected the problem and will release a patch in due course (Quix case #
QXCM1001115136).
· On VMS, there were a handful of "Module::Build" test failures we didn't get to before the release; please
watch CPAN for updates.
Errata
keys(), values(), and each() work on arrays
You can now use the keys(), values(), and each() builtins on arrays; previously you could use them only on
hashes. See perlfunc for details. This is actually a change introduced in perl 5.12.0, but it was missed
from that release's perl5120delta.
split() and @_
split() no longer modifies @_ when called in scalar or void context. In void context it now produces a
"Useless use of split" warning. This was also a perl 5.12.0 change that missed the perldelta.
Obituary
Randy Kobes, creator of http://kobesearch.cpan.org/ and contributor/maintainer to several core Perl toolchain
modules, passed away on September 18, 2010 after a battle with lung cancer. The community was richer for his
involvement. He will be missed.
Acknowledgements
Perl 5.14.0 represents one year of development since Perl 5.12.0 and contains nearly 550,000 lines of changes
across nearly 3,000 files from 150 authors and committers.
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 5.14.0:
Aaron Crane, Abhijit Menon-Sen, Abigail, var Arnfjoer` Bjarmason, Alastair Douglas, Alexander Alekseev,
Alexander Hartmaier, Alexandr Ciornii, Alex Davies, Alex Vandiver, Ali Polatel, Allen Smith, Andreas Koenig,
Andrew Rodland, Andy Armstrong, Andy Dougherty, Aristotle Pagaltzis, Arkturuz, Arvan, A. Sinan Unur, Ben
Morrow, Bo Lindbergh, Boris Ratner, Brad Gilbert, Bram, brian d foy, Brian Phillips, Casey West, Charles
Bailey, Chas. Owens, Chip Salzenberg, Chris 'BinGOs' Williams, chromatic, Craig A. Berry, Curtis Jewell,
Dagfinn Ilmari Mannsaaker, Dan Dascalescu, Dave Rolsky, David Caldwell, David Cantrell, David Golden, David
Leadbeater, David Mitchell, David Wheeler, Eric Brine, Father Chrysostomos, Fingle Nark, Florian Ragwitz,
Frank Wiegand, Franz Fasching, Gene Sullivan, George Greer, Gerard Goossen, Gisle Aas, Goro Fuji, Grant
McLean, gregor herrmann, H.Merijn Brand, Hongwen Qiu, Hugo van der Sanden, Ian Goodacre, James E Keenan, James
Mastros, Jan Dubois, Jay Hannah, Jerry D. Hedden, Jesse Vincent, Jim Cromie, Jirka HruXka, John Peacock,
Joshua ben Jore, Joshua Pritikin, Karl Williamson, Kevin Ryde, kmx, Lars DXXXXXX XXX, Larwan Berke, Leon
doesn't include the names of the (very much appreciated) contributors who reported issues in previous versions
of Perl that helped make Perl 5.14.0 better. For a more complete list of all of Perl's historical
contributors, please see the "AUTHORS" file in the Perl 5.14.0 distribution.
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.
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://rt.perl.org/perlbug/ . There may also be information at
http://www.perl.org/ , the Perl Home Page.
If you believe you have an unreported bug, please run the 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 "perl
-V", will be sent off to [email protected] 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 [email protected]. This points to a closed
subscription unarchived mailing list, which includes all the core committers, who are 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 for security issues in the
Perl core only, not for modules independently distributed on CPAN.
SEE ALSO
The Changes file for an explanation of how to view exhaustive details on what changed.
The INSTALL file for how to build Perl.
The README file for general stuff.
The Artistic and Copying files for copyright information.
perl v5.16.3 2013-03-04 PERL5140DELTA(1)
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