text:
- Core Enhancements
- New mechanism for experimental features
- Hash overhaul
- Upgrade to Unicode 6.2
- Character name aliases may now include non-Latin1-range characters
- New DTrace probes
- Regular Expression Set Operations
- Lexical subroutines
- Computed Labels
- More CORE:: subs
- kill with negative signal names
- Security
- Incompatible Changes
- See also: hash overhaul
- An unknown character name in \N{...} is now a syntax error
- Formerly deprecated characters in \N{} character name aliases are now errors.
- \N{BELL} now refers to U+1F514 instead of U+0007
- New Restrictions in Multi-Character Case-Insensitive Matching in Regular Expression Bracketed Character Classes
- Explicit rules for variable names and identifiers
- \s in regular expressions now matches a Vertical Tab
- /(?{})/ and /(??{})/ have been heavily reworked
- Stricter parsing of substitution replacement
- given now aliases the global $_
- The smartmatch family of features are now experimental
- Lexical $_ is now experimental
- readline() with $/ = \N now reads N characters, not N bytes
- Overridden glob is now passed one argument
- Here-doc parsing
- Alphanumeric operators must now be separated from the closing delimiter of regular expressions
- qw(...) can no longer be used as parentheses
- Interaction of lexical and default warnings
- state sub and our sub
- Defined values stored in environment are forced to byte strings
- require dies for unreadable files
- gv_fetchmeth_* and SUPER
- split's first argument is more consistently interpreted
- Deprecations
- Deprecated modules
- Deprecated Utilities
- PL_sv_objcount
- Five additional characters should be escaped in patterns with /x
- User-defined charnames with surprising whitespace
- Various XS-callable functions are now deprecated
- Certain rare uses of backslashes within regexes are now deprecated
- Splitting the tokens (? and (* in regular expressions
- Pre-PerlIO IO implementations
- Future Deprecations
- Performance Enhancements
- Modules and Pragmata
- Documentation
- Utility Changes
- Configuration and Compilation
- Testing
- Platform Support
- Internal Changes
- Selected Bug Fixes
- Known Problems
- Acknowledgements
- Reporting Bugs
perldelta - what is new for perl v5.18.0
This document describes differences between the v5.16.0 release and the v5.18.0 release.
If you are upgrading from an earlier release such as v5.14.0, first read perl5160delta, which describes differences between v5.14.0 and v5.16.0.
Core Enhancements
New mechanism for experimental features
Newly-added experimental features will now require this incantation:
no warnings "experimental::feature_name";
use feature "feature_name"; # would warn without the prev line
There is a new warnings category, called "experimental", containing warnings that the feature pragma emits when enabling experimental features.
Newly-added experimental features will also be given special warning IDs, which consist of "experimental::" followed by the name of the feature. (The plan is to extend this mechanism eventually to all warnings, to allow them to be enabled or disabled individually, and not just by category.)
By saying
no warnings "experimental::feature_name";
you are taking responsibility for any breakage that future changes to, or removal of, the feature may cause.
Since some features (like
~~ or
my $_) now emit experimental warnings, and you may want to disable them in code that is also run on perls that do not recognize these warning categories, consider using the
if pragma like this:
no if $] >= 5.018, 'warnings', "experimental::feature_name";
Existing experimental features may begin emitting these warnings, too. Please consult perlexperiment for information on which features are considered experimental.
Hash overhaul
Changes to the implementation of hashes in perl v5.18.0 will be one of the most visible changes to the behavior of existing code.
By default, two distinct hash variables with identical keys and values may now provide their contents in a different order where it was previously identical.
When encountering these changes, the key to cleaning up from them is to accept that hashes are unordered collections and to act accordingly.
Hash randomization
The seed used by Perl's hash function is now random. This means that the order which keys/values will be returned from functions like
values(), and
each() will differ from run to run.
This change was introduced to make Perl's hashes more robust to algorithmic complexity attacks, and also because we discovered that it exposes hash ordering dependency bugs and makes them easier to track down.
Toolchain maintainers might want to invest in additional infrastructure to test for things like this. Running tests several times in a row and then comparing results will make it easier to spot hash order dependencies in code. Authors are strongly encouraged not to expose the key order of Perl's hashes to insecure audiences.
Further, every hash has its own iteration order, which should make it much more difficult to determine what the current hash seed is.
New hash functions
Perl v5.18 includes support for multiple hash functions, and changed the default (to ONE_AT_A_TIME_HARD), you can choose a different algorithm by defining a symbol at compile time. For a current list, consult the INSTALL document. Note that as of Perl v5.18 we can only recommend use of the default or SIPHASH. All the others are known to have security issues and are for research purposes only.
PERL_HASH_SEED environment variable now takes a hex value
PERL_HASH_SEED no longer accepts an integer as a parameter; instead the value is expected to be a binary value encoded in a hex string, such as "0xf5867c55039dc724". This is to make the infrastructure support hash seeds of arbitrary lengths, which might exceed that of an integer. (SipHash uses a 16 byte seed).
PERL_PERTURB_KEYS environment variable added
PERL_PERTURB_KEYS environment variable allows one to control the level of randomization applied to
keys and friends.
PERL_PERTURB_KEYS is 0, perl will not randomize the key order at all. The chance that
keys changes due to an insert will be the same as in previous perls, basically only when the bucket size is changed.
PERL_PERTURB_KEYS is 1, perl will randomize keys in a non-repeatable way. The chance that
keys changes due to an insert will be very high. This is the most secure and default mode.
PERL_PERTURB_KEYS is 2, perl will randomize keys in a repeatable way. Repeated runs of the same program should produce the same output every time.
PERL_HASH_SEED implies a non-default
PERL_PERTURB_KEYS setting. Setting
PERL_HASH_SEED=0 (exactly one 0) implies
PERL_PERTURB_KEYS=0 (hash key randomization disabled); settng
PERL_HASH_SEED to any other value implies
PERL_PERTURB_KEYS=2 (deterministic and repeatable hash key randomization). Specifying
PERL_PERTURB_KEYS explicitly to a different level overrides this behavior.
Hash::Util::hash_seed() now returns a string
Hash::Util::hash_seed() now returns a string instead of an integer. This is to make the infrastructure support hash seeds of arbitrary lengths which might exceed that of an integer. (SipHash uses a 16 byte seed).
Output of PERL_HASH_SEED_DEBUG has been changed
The environment variable PERL_HASH_SEED_DEBUG now makes perl show both the hash function perl was built with, and the seed, in hex, in use for that process. Code parsing this output, should it exist, must change to accommodate the new format. Example of the new format:
$ PERL_HASH_SEED_DEBUG=1 ./perl -e1
HASH_FUNCTION = MURMUR3 HASH_SEED = 0x1476bb9f
Upgrade to Unicode 6.2
Perl now supports Unicode 6.2. A list of changes from Unicode 6.1 is at http://www.unicode.org/versions/Unicode6.2.0.
Character name aliases may now include non-Latin1-range characters
It is possible to define your own names for characters for use in
charnames::vianame(), etc. These names can now be comprised of characters from the whole Unicode range. This allows for names to be in your native language, and not just English. Certain restrictions apply to the characters that may be used (you can't define a name that has punctuation in it, for example). See "CUSTOM ALIASES" in charnames.
New DTrace probes
The following new DTrace probes have been added:
This new variable provides access to the filehandle that was last read. This is the handle used by
$. and by
tell and
eof without arguments.
Regular Expression Set Operations
This is an experimental feature to allow matching against the union, intersection, etc., of sets of code points, similar to Unicode::Regex::Set. It can also be used to extend
/x processing to [bracketed] character classes, and as a replacement of user-defined properties, allowing more complex expressions than they do. See "Extended Bracketed Character Classes" in perlrecharclass.
Lexical subroutines
This new feature is still considered experimental. To enable it:
use 5.018;
no warnings "experimental::lexical_subs";
use feature "lexical_subs";
You can now declare subroutines with
state sub foo,
my sub foo, and
our sub foo. (
state sub requires that the "state" feature be enabled, unless you write it as
CORE::state sub foo.)
state sub creates a subroutine visible within the lexical scope in which it is declared. The subroutine is shared between calls to the outer sub.
my sub declares a lexical subroutine that is created each time the enclosing block is entered.
state sub is generally slightly faster than
my sub.
our sub declares a lexical alias to the package subroutine of the same name.
For more information, see "Lexical Subroutines" in perlsub.
Computed Labels
The loop controls
last and
redo, and the special
dump operator, now allow arbitrary expressions to be used to compute labels at run time. Previously, any argument that was not a constant was treated as the empty string.
More CORE:: subs
Several more built-in functions have been added as subroutines to the CORE:: namespace - namely, those non-overridable keywords that can be implemented without custom parsers:
study, and
As some of these have prototypes,
prototype('CORE::...') has been changed to not make a distinction between overridable and non-overridable keywords. This is to make
prototype('CORE::pos') consistent with
kill with negative signal names
kill has always allowed a negative signal number, which kills the process group instead of a single process. It has also allowed signal names. But it did not behave consistently, because negative signal names were treated as 0. Now negative signals names like
-INT are supported and treated the same way as -2 [perl #112990].
Storable security warning in documentation
The documentation for
Storable now includes a section which warns readers of the danger of accepting Storable documents from untrusted sources. The short version is that deserializing certain types of data can lead to loading modules and other code execution. This is documented behavior and wanted behavior, but this opens an attack vector for malicious entities.
Locale::Maketext allowed code injection via a malicious template
If users could provide a translation string to Locale::Maketext, this could be used to invoke arbitrary Perl subroutines available in the current process.
This has been fixed, but it is still possible to invoke any method provided by
Locale::Maketext itself or a subclass that you are using. One of these methods in turn will invoke the Perl core's
sprintf subroutine.
In summary, allowing users to provide translation strings without auditing them is a bad idea.
This vulnerability is documented in CVE-2012-6329.
Avoid calling memset with a negative count
Poorly written perl code that allows an attacker to specify the count to perl's
x string repeat operator can already cause a memory exhaustion denial-of-service attack. A flaw in versions of perl before v5.15.5 can escalate that into a heap buffer overrun; coupled with versions of glibc before 2.16, it possibly allows the execution of arbitrary code.
The flaw addressed to this commit has been assigned identifier CVE-2012-5195 and was researched by Tim Brown.
Incompatible Changes
See also: hash overhaul
Some of the changes in the hash overhaul are not fully compatible with previous versions of perl. Please read that section.
An unknown character name in
\N{...} is now a syntax error
Previously, it warned, and the Unicode REPLACEMENT CHARACTER was substituted. Unicode now recommends that this situation be a syntax error. Also, the previous behavior led to some confusing warnings and behaviors, and since the REPLACEMENT CHARACTER has no use other than as a stand-in for some unknown character, any code that has this problem is buggy.
Formerly deprecated characters in
\N{} character name aliases are now errors.
Since v5.12.0, it has been deprecated to use certain characters in user-defined
\N{...} character names. These now cause a syntax error. For example, it is now an error to begin a name with a digit, such as in
my $undraftable = "\N{4F}"; # Syntax error!
or to have commas anywhere in the name. See "CUSTOM ALIASES" in charnames.
\N{BELL} now refers to U+1F514 instead of U+0007
Unicode 6.0 reused the name "BELL" for a different code point than it traditionally had meant. Since Perl v5.14, use of this name still referred to U+0007, but would raise a deprecation warning. Now, "BELL" refers to U+1F514, and the name for U+0007 is "ALERT". All the functions in charnames have been correspondingly updated.
New Restrictions in Multi-Character Case-Insensitive Matching in Regular Expression Bracketed Character Classes
Unicode has now withdrawn their previous recommendation for regular expressions to automatically handle cases where a single character can match multiple characters case-insensitively, for example, the letter LATIN SMALL LETTER SHARP S and the sequence
ss. This is because it turns out to be impracticable to do this correctly in all circumstances. Because Perl has tried to do this as best it can, it will continue to do so. (We are considering an option to turn it off.) However, a new restriction is being added on such matches when they occur in [bracketed] character classes. People were specifying things such as
/[\0-\xff]/i, and being surprised that it matches the two character sequence
ss (since LATIN SMALL LETTER SHARP S occurs in this range). This behavior is also inconsistent with using a property instead of a range:
\p{Block=Latin1} also includes LATIN SMALL LETTER SHARP S, but
/[\p{Block=Latin1}]/i does not match
ss. The new rule is that for there to be a multi-character case-insensitive match within a bracketed character class, the character must be explicitly listed, and not as an end point of a range. This more closely obeys the Principle of Least Astonishment. See "Bracketed Character Classes" in perlrecharclass. Note that a bug [perl #89774], now fixed as part of this change, prevented the previous behavior from working fully.
Explicit rules for variable names and identifiers
Due to an oversight, single character variable names in v5.16 were completely unrestricted. This opened the door to several kinds of insanity. As of v5.18, these now follow the rules of other identifiers, in addition to accepting characters that match the
\p{POSIX_Punct} property.
There are no longer any differences in the parsing of identifiers specified as
$... or
${...}; previously, they were dealt with in different parts of the core, and so had slightly different behavior. For instance,
${foo:bar} was a legal variable name. Since they are now both parsed by the same code, that is no longer the case.
\s in regular expressions now matches a Vertical Tab
No one could recall why
\s didn't match
\cK, the vertical tab. Now it does. Given the extreme rarity of that character, very little breakage is expected.
/(?{})/ and
/(??{})/ have been heavily reworked
The implementation of this feature has been almost completely rewritten. Although its main intent is to fix bugs, some behaviors, especially related to the scope of lexical variables, will have changed. This is described more fully in the "Selected Bug Fixes" section.
Stricter parsing of substitution replacement
It is no longer possible to abuse the way the parser parses
s///e like this:
%_=(_,"Just another ");
$_="Perl hacker,\n";
given now aliases the global
Instead of assigning to an implicit lexical
given now makes the global
$_ an alias for its argument, just like
foreach. However, it still uses lexical
$_ if there is lexical
$_ in scope (again, just like
foreach) [perl #114020].
The smartmatch family of features are now experimental
Smart match, added in v5.10.0 and significantly revised in v5.10.1, has been a regular point of complaint. Although there are a number of ways in which it is useful, it has also proven problematic and confusing for both users and implementors of Perl. There have been a number of proposals on how to best address the problem. It is clear that smartmatch is almost certainly either going to change or go away in the future. Relying on its current behavior is not recommended.
Warnings will now be issued when the parser sees
given, or
when. To disable these warnings, you can add this line to the appropriate scope:
no if $] >= 5.018, "experimental::smartmatch";
Consider, though, replacing the use of these features, as they may change behavior again before becoming stable.
$_ is now experimental
Since it was introduced in Perl v5.10, it has caused much confusion with no obvious solution:
Various modules (e.g., List::Util) expect callback routines to use the global
use List::Util 'first'; my $_; first { $_ == 1 } @listdoes not work as one would expect.
my $_declaration earlier in the same file can cause confusing closure warnings.
The "_" subroutine prototype character allows called subroutines to access your lexical
$_, so it is not really private after all.
Nevertheless, subroutines with a "(@)" prototype and methods cannot access the caller's lexical
$_, unless they are written in XS.
But even XS routines cannot access a lexical
$_declared, not in the calling subroutine, but in an outer scope, iff that subroutine happened not to mention
$_or use any operators that default to
It is our hope that lexical
$_ can be rehabilitated, but this may cause changes in its behavior. Please use it with caution until it becomes stable.
readline() with
$/ = \N now reads N characters, not N bytes
Previously, when reading from a stream with I/O layers such as
encoding, the readline() function, otherwise known as the
<> operator, would read N bytes from the top-most layer. [perl #79960]
Now, N characters are read instead.
There is no change in behaviour when reading from streams with no extra layers, since bytes map exactly to characters.
glob is now passed one argument
glob overrides used to be passed a magical undocumented second argument that identified the caller. Nothing on CPAN was using this, and it got in the way of a bug fix, so it was removed. If you really need to identify the caller, see Devel::Callsite on CPAN.
Here-doc parsing
The body of a here-document inside a quote-like operator now always begins on the line after the "<<foo" marker. Previously, it was documented to begin on the line following the containing quote-like operator, but that was only sometimes the case [perl #114040].
Alphanumeric operators must now be separated from the closing delimiter of regular expressions
You may no longer write something like:
m/a/and 1
Instead you must write
m/a/ and 1
with whitespace separating the operator from the closing delimiter of the regular expression. Not having whitespace has resulted in a deprecation warning since Perl v5.14.0.
qw(...) can no longer be used as parentheses
qw lists used to fool the parser into thinking they were always surrounded by parentheses. This permitted some surprising constructions such as
foreach $x qw(a b c) {...}, which should really be written
foreach $x (qw(a b c)) {...}. These would sometimes get the lexer into the wrong state, so they didn't fully work, and the similar
foreach qw(a b c) {...} that one might expect to be permitted never worked at all.
This side effect of
qw has now been abolished. It has been deprecated since Perl v5.13.11. It is now necessary to use real parentheses everywhere that the grammar calls for them.
Interaction of lexical and default warnings
Turning on any lexical warnings used first to disable all default warnings if lexical warnings were not already enabled:
$*; # deprecation warning
use warnings "void";
$#; # void warning; no deprecation warning
Now, the
inplace and
malloc warnings categories are left on when turning on lexical warnings (unless they are turned off by
no warnings, of course).
This may cause deprecation warnings to occur in code that used to be free of warnings.
Those are the only categories consisting only of default warnings. Default warnings in other categories are still disabled by
use warnings "category", as we do not yet have the infrastructure for controlling individual warnings.
state sub and
our sub
Due to an accident of history,
state sub and
our sub were equivalent to a plain
sub, so one could even create an anonymous sub with
our sub { ... }. These are now disallowed outside of the "lexical_subs" feature. Under the "lexical_subs" feature they have new meanings described in "Lexical Subroutines" in perlsub.
Defined values stored in environment are forced to byte strings
A value stored in an environment variable has always been stringified. In this release, it is converted to be only a byte string. First, it is forced to be only a string. Then if the string is utf8 and the equivalent of
utf8::downgrade() works, that result is used; otherwise, the equivalent of
utf8::encode() is used, and a warning is issued about wide characters ("Diagnostics").
require dies for unreadable files
require encounters an unreadable file, it now dies. It used to ignore the file and continue searching the directories in
@INC [perl #113422].
gv_fetchmeth_* and SUPER
The various
gv_fetchmeth_* XS functions used to treat a package whose named ended with
::SUPER specially. A method lookup on the
Foo::SUPER package would be treated as a
SUPER method lookup on the
Foo package. This is no longer the case. To do a
SUPER lookup, pass the
Foo stash and the
GV_SUPER flag.
split's first argument is more consistently interpreted
After some changes earlier in v5.17,
split's behavior has been simplified: if the PATTERN argument evaluates to a literal string containing one space, it is treated the way that a literal string containing one space once was.
Deprecated modules
The following modules will be removed from the core distribution in a future release, and should be installed from CPAN instead. Distributions on CPAN which require these should add them to their prerequisites. The core versions of these modules will issue
"deprecated"-category warnings.
You can silence these deprecation warnings by installing the modules in question from CPAN.
- Archive::Extract
- B::Lint
- B::Lint::Debug
- CPANPLUS and all included
- Devel::InnerPackage
- encoding
- Log::Message
- Log::Message::Config
- Log::Message::Handlers
- Log::Message::Item
- Log::Message::Simple
- Module::Pluggable
- Module::Pluggable::Object
- Object::Accessor
- Pod::LaTeX
- Term::UI
- Term::UI::History
Deprecated Utilities
The following utilities will be removed from the core distribution in a future release as their associated modules have been deprecated. They will remain available with the applicable CPAN distribution.
- cpanp
- cpan2dist
These items are part of the
- pod2latex
This item is part of the
This interpreter-global variable used to track the total number of Perl objects in the interpreter. It is no longer maintained and will be removed altogether in Perl v5.20.
Five additional characters should be escaped in patterns with
When a regular expression pattern is compiled with
/x, Perl treats 6 characters as white space to ignore, such as SPACE and TAB. However, Unicode recommends 11 characters be treated thusly. We will conform with this in a future Perl version. In the meantime, use of any of the missing characters will raise a deprecation warning, unless turned off. The five characters are:
User-defined charnames with surprising whitespace
A user-defined character name with trailing or multiple spaces in a row is likely a typo. This now generates a warning when defined, on the assumption that uses of it will be unlikely to include the excess whitespace.
Various XS-callable functions are now deprecated
All the functions used to classify characters will be removed from a future version of Perl, and should not be used. With participating C compilers (e.g., gcc), compiling any file that uses any of these will generate a warning. These were not intended for public use; there are equivalent, faster, macros for most of them.
See "Character classes" in perlapi. The complete list is:
In addition these three functions that have never worked properly are deprecated:
to_uni_title_lc, and
Certain rare uses of backslashes within regexes are now deprecated
There are three pairs of characters that Perl recognizes as metacharacters in regular expression patterns:
[], and
(). These can be used as well to delimit patterns, as in:
Since they are metacharacters, they have special meaning to regular expression patterns, and it turns out that you can't turn off that special meaning by the normal means of preceding them with a backslash, if you use them, paired, within a pattern delimited by them. For example, in
the backslashes do not change the behavior, and this matches
"f o" followed by one to three more occurrences of
Usages like this, where they are interpreted as metacharacters, are exceedingly rare; we think there are none, for example, in all of CPAN. Hence, this deprecation should affect very little code. It does give notice, however, that any such code needs to change, which will in turn allow us to change the behavior in future Perl versions so that the backslashes do have an effect, and without fear that we are silently breaking any existing code.
Splitting the tokens
(? and
(* in regular expressions
A deprecation warning is now raised if the
( and
? are separated by white space or comments in
(?...) regular expression constructs. Similarly, if the
( and
* are separated in
(*VERB...) constructs.
Pre-PerlIO IO implementations
Perl supports being built without PerlIO proper, using a stdio or sfio wrapper instead. A perl build like this will not support IO layers and thus Unicode IO, making it rather handicapped.
PerlIO supports a
stdio layer if stdio use is desired, and similarly a sfio layer could be produced.
Future Deprecations
Platforms without support infrastructure
Both Windows CE and z/OS have been historically under-maintained, and are currently neither successfully building nor regularly being smoke tested. Efforts are underway to change this situation, but it should not be taken for granted that the platforms are safe and supported. If they do not become buildable and regularly smoked, support for them may be actively removed in future releases. If you have an interest in these platforms and you can lend your time, expertise, or hardware to help support these platforms, please let the perl development effort know by emailing
Some platforms that appear otherwise entirely dead are also on the short list for removal between now and v5.20.0:
We also think it likely that current versions of Perl will no longer build AmigaOS, DJGPP, NetWare (natively), OS/2 and Plan 9. If you are using Perl on such a platform and have an interest in ensuring Perl's future on them, please contact us.
We believe that Perl has long been unable to build on mixed endian architectures (such as PDP-11s), and intend to remove any remain support code. Similarly, code supporting the long umaintained GNU dld will be removed soon if no-one makes themselves known as an active user.
Swapping of $< and $>
For more information about this future deprecation, see the relevant RT ticket.
microperl, long broken and of unclear present purpose, will be removed.
"\Q"semantics in double-quotish strings when combined with other escapes.
There are several bugs and inconsistencies involving combinations of
\Qand escapes like
\L, etc., within a
\Q...\Epair. These need to be fixed, and doing so will necessarily change current behavior. The changes have not yet been settled.
Use of
$^, where
^stands for any actual (non-printing) C0 control character will be disallowed in a future Perl version. Use
${^}instead (where again
^stands for a control character), or better,
$^A, where
^this time is a caret (CIRCUMFLEX ACCENT), and
Astands for any of the characters listed at the end of "OPERATOR DIFFERENCES" in perlebcdic.
Performance Enhancements
Lists of lexical variable declarations (
my($x, $y)) are now optimised down to a single op and are hence faster than before.
A new C preprocessor define
NO_TAINT_SUPPORTwas added that, if set, disables Perl's taint support altogether. Using the -T or -t command line flags will cause a fatal error. Beware that both core tests as well as many a CPAN distribution's tests will fail with this change. On the upside, it provides a small performance benefit due to reduced branching.
Do not enable this unless you know exactly what you are getting yourself into.
packwith constant arguments is now constant folded in most cases [perl #113470].
Speed up in regular expression matching against Unicode properties. The largest gain is for
\X, the Unicode "extended grapheme cluster." The gain for it is about 35% - 40%. Bracketed character classes, e.g.,
[0-9\x{100}]containing code points above 255 are also now faster.
On platforms supporting it, several former macros are now implemented as static inline functions. This should speed things up slightly on non-GCC platforms.
The optimisation of hashes in boolean context has been extended to affect
%hash ? ... : ..., and
sub { %hash || ... }.
Filetest operators manage the stack in a fractionally more efficient manner.
Globs used in a numeric context are now numified directly in most cases, rather than being numified via stringification.
xrepetition operator is now folded to a single constant at compile time if called in scalar context with constant operands and no parentheses around the left operand.
Modules and Pragmata
New Modules and Pragmata
Config::Perl::V version 0.16 has been added as a dual-lifed module. It provides structured data retrieval of
perl -Voutput including information only known to the
perlbinary and not available via Config.
Updated Modules and Pragmata
For a complete list of updates, run:
$ corelist --diff 5.16.0 5.18.0
You can substitute your favorite version in place of
5.16.0, too.
Removed Modules and Pragmata
Version::Requirements has been removed from the core distribution. It is available under a different name: CPAN::Meta::Requirements.
Changes to Existing Documentation
perlcheat has been reorganized, and a few new sections were added.
Now explicitly documents the behaviour of hash initializer lists that contain duplicate keys.
The explanation of symbolic references being prevented by "strict refs" now doesn't assume that the reader knows what symbolic references are.
perlfaq has been synchronized with version 5.0150040 from CPAN.
The return value of
pipeis now documented.
Clarified documentation of
Loop control verbs (
redo) have always had the same precedence as assignment operators, but this was not documented until now.
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
Unterminated delimiter for here document
This message now occurs when a here document label has an initial quotation mark but the final quotation mark is missing.
This replaces a bogus and misleading error message about not finding the label itself [perl #114104].
panic: child pseudo-process was never scheduled
This error is thrown when a child pseudo-process in the ithreads implementation on Windows was not scheduled within the time period allowed and therefore was not able to initialize properly [perl #88840].
Group name must start with a non-digit word character in regex; marked by <-- HERE in m/%s/
This error has been added for
(?&0), which is invalid. It used to produce an incomprehensible error message [perl #101666].
Can't use an undefined value as a subroutine reference
Calling an undefined value as a subroutine now produces this error message. It used to, but was accidentally disabled, first in Perl 5.004 for non-magical variables, and then in Perl v5.14 for magical (e.g., tied) variables. It has now been restored. In the mean time, undef was treated as an empty string [perl #113576].
Experimental "%s" subs not enabled
To use lexical subs, you must first enable them:
no warnings 'experimental::lexical_subs'; use feature 'lexical_subs'; my sub foo { ... }
New Warnings
Strings with code points over 0xFF may not be mapped into in-memory file handles
'Trailing white-space in a charnames alias definition is deprecated'
'A sequence of multiple spaces in a charnames alias definition is deprecated'
Subroutine "&%s" is not available
(W closure) During compilation, an inner named subroutine or eval is attempting to capture an outer lexical subroutine that is not currently available. This can happen for one of two reasons. First, the lexical subroutine may be declared in an outer anonymous subroutine that has not yet been created. (Remember that named subs are created at compile time, while anonymous subs are created at run-time.) For example,
sub { my sub a {...} sub f { \&a } }
At the time that f is created, it can't capture the current the "a" sub, since the anonymous subroutine hasn't been created yet. Conversely, the following won't give a warning since the anonymous subroutine has by now been created and is live:
sub { my sub a {...} eval 'sub f { \&a }' }->();
The second situation is caused by an eval accessing a variable that has gone out of scope, for example,
sub f { my sub a {...} sub { eval '\&a' } } f()->();
Here, when the '\&a' in the eval is being compiled, f() is not currently being executed, so its &a is not available for capture.
"%s" subroutine &%s masks earlier declaration in same %s
(W misc) A "my" or "state" subroutine has been redeclared in the current scope or statement, effectively eliminating all access to the previous instance. This is almost always a typographical error. Note that the earlier subroutine will still exist until the end of the scope or until all closure references to it are destroyed.
The %s feature is experimental
(S experimental) This warning is emitted if you enable an experimental feature via
use feature. Simply suppress the warning if you want to use the feature, but know that in doing so you are taking the risk of using an experimental feature which may change or be removed in a future Perl version:
no warnings "experimental::lexical_subs"; use feature "lexical_subs";
(W overflow) You called
sleepwith a number that was larger than it can reliably handle and
sleepprobably slept for less time than requested.
Attempts to put wide characters into environment variables via
%ENVnow provoke this warning.
"Invalid negative number (%s) in chr"
chr()now warns when passed a negative value [perl #83048].
srand()now warns when passed a value that doesn't fit in a
UV(since the value will be truncated rather than overflowing) [perl #40605].
"-i used with no filenames on the command line, reading from STDIN"
Running perl with the
-iflag now warns if no input files are provided on the command line [perl #113410].
Changes to Existing Diagnostics
The warning that use of
$#is no longer supported is now generated for every location that references them. Previously it would fail to be generated if another variable using the same typeglob was seen first (e.g.
$*), and would not be generated for the second and subsequent uses. (It's hard to fix the failure to generate warnings at all without also generating them every time, and warning every time is consistent with the warnings that
$[used to generate.)
The warnings for
\B{were added. They are a deprecation warning which should be turned off by that category. One should not have to turn off regular regexp warnings as well to get rid of these.
Constant(%s): Call to &{$^H{%s}} did not return a defined value
Constant overloading that returns
undefresults in this error message. For numeric constants, it used to say "Constant(undef)". "undef" has been replaced with the number itself.
The error produced when a module cannot be loaded now includes a hint that the module may need to be installed: "Can't locate hopping.pm in @INC (you may need to install the hopping module) (@INC contains: ...)"
vector argument not supported with alpha versions
This warning was not suppressable, even with
no warnings. Now it is suppressible, and has been moved from the "internal" category to the "printf" category.
Can't do {n,m} with n > m in regex; marked by <-- HERE in m/%s/
This fatal error has been turned into a warning that reads:
Quantifier {n,m} with n > m can't match in regex
(W regexp) Minima should be less than or equal to maxima. If you really want your regexp to match something 0 times, just put {0}.
The "Runaway prototype" warning that occurs in bizarre cases has been removed as being unhelpful and inconsistent.
The "Not a format reference" error has been removed, as the only case in which it could be triggered was a bug.
The "Unable to create sub named %s" error has been removed for the same reason.
The 'Can't use "my %s" in sort comparison' error has been downgraded to a warning, '"my %s" used in sort comparison' (with 'state' instead of 'my' for state variables). In addition, the heuristics for guessing whether lexical $a or $b has been misused have been improved to generate fewer false positives. Lexical $a and $b are no longer disallowed if they are outside the sort block. Also, a named unary or list operator inside the sort block no longer causes the $a or $b to be ignored [perl #86136].
Utility Changes
h2xs no longer produces invalid code for empty defines. [perl #20636]
Configuration and Compilation
useversionedarchnameoption to Configure
When set, it includes 'api_versionstring' in 'archname'. E.g. x86_64-linux-5.13.6-thread-multi. It is unset by default.
This feature was requested by Tim Bunce, who observed that
INSTALL_BASEcreates a library structure that does not differentiate by perl version. Instead, it places architecture specific files in "$install_base/lib/perl5/$archname". This makes it difficult to use a common
INSTALL_BASElibrary path with multiple versions of perl.
By setting
-Duseversionedarchname, the $archname will be distinct for architecture and API version, allowing mixed use of
Add a
PERL_NO_INLINE_FUNCTIONSis defined, don't include "inline.h"
This permits test code to include the perl headers for definitions without creating a link dependency on the perl library (which may not exist yet).
Configure will honour the external
MAILDOMAINenvironment variable, if set.
installmanno longer ignores the silent option
META.jsonfiles are now included in the distribution.
Configure will now correctly detect
isblank()when compiling with a C++ compiler.
The pager detection in Configure has been improved to allow responses which specify options after the program name, e.g. /usr/bin/less -R, if the user accepts the default value. This helps perldoc when handling ANSI escapes [perl #72156].
The test suite now has a section for tests that require very large amounts of memory. These tests won't run by default; they can be enabled by setting the
PERL_TEST_MEMORYenvironment variable to the number of gibibytes of memory that may be safely used.
Platform Support
Discontinued Platforms
- BeOS
BeOS was an operating system for personal computers developed by Be Inc, initially for their BeBox hardware. The OS Haiku was written as an open source replacement for/continuation of BeOS, and its perl port is current and actively maintained.
- UTS Global
Support code relating to UTS global has been removed. UTS was a mainframe version of System V created by Amdahl, subsequently sold to UTS Global. The port has not been touched since before Perl v5.8.0, and UTS Global is now defunct.
Support for VM/ESA has been removed. The port was tested on 2.3.0, which IBM ended service on in March 2002. 2.4.0 ended service in June 2003, and was superseded by Z/VM. The current version of Z/VM is V6.2.0, and scheduled for end of service on 2015/04/30.
Support for MPE/IX has been removed.
Support code relating to EPOC has been removed. EPOC was a family of operating systems developed by Psion for mobile devices. It was the predecessor of Symbian. The port was last updated in April 2002.
- Rhapsody
Support for Rhapsody has been removed.
Platform-Specific Notes
Configure now always adds
-qlanglvl=extc99 to the CC flags on AIX when using xlC. This will make it easier to compile a number of XS-based modules that assume C99 [perl #113778].
There is now a workaround for a compiler bug that prevented compiling with clang++ since Perl v5.15.7 [perl #112786].
When compiling the Perl core as C++ (which is only semi-supported), the mathom functions are now compiled as
extern "C", to ensure proper binary compatibility. (However, binary compatibility isn't generally guaranteed anyway in the situations where this would matter.)
Stop hardcoding an alignment on 8 byte boundaries to fix builds using -Dusemorebits.
Perl should now work out of the box on Haiku R1 Alpha 4.
libc_r was removed from recent versions of MidnightBSD and older versions work better with
pthread. Threading is now enabled using
pthread which corrects build errors with threading enabled on 0.4-CURRENT.
In Configure, avoid running sed commands with flags not supported on Solaris.
Where possible, the case of filenames and command-line arguments is now preserved by enabling the CRTL features
DECC$ARGV_PARSE_STYLEat start-up time. The latter only takes effect when extended parse is enabled in the process from which Perl is run.
The character set for Extended Filename Syntax (EFS) is now enabled by default on VMS. Among other things, this provides better handling of dots in directory names, multiple dots in filenames, and spaces in filenames. To obtain the old behavior, set the logical name
Fixed linking on builds configured with
Experimental support for building Perl with the HP C++ compiler is available by configuring with
All C header files from the top-level directory of the distribution are now installed on VMS, providing consistency with a long-standing practice on other platforms. Previously only a subset were installed, which broke non-core extension builds for extensions that depended on the missing include files.
Quotes are now removed from the command verb (but not the parameters) for commands spawned via
system, backticks, or a piped
open. Previously, quotes on the verb were passed through to DCL, which would fail to recognize the command. Also, if the verb is actually a path to an image or command procedure on an ODS-5 volume, quoting it now allows the path to contain spaces.
The a2p build has been fixed for the HP C++ compiler on OpenVMS.
Perl can now be built using Microsoft's Visual C++ 2012 compiler by specifying CCTYPE=MSVC110 (or MSVC110FREE if you are using the free Express edition for Windows Desktop) in win32/Makefile.
The option to build without
USE_SOCKETS_AS_HANDLEShas been removed.
Fixed a problem where perl could crash while cleaning up threads (including the main thread) in threaded debugging builds on Win32 and possibly other platforms [perl #114496].
A rare race condition that would lead to sleep taking more time than requested, and possibly even hanging, has been fixed [perl #33096].
linkon Win32 now attempts to set
$!to more appropriate values based on the Win32 API error code. [perl #112272]
Perl no longer mangles the environment block, e.g. when launching a new sub-process, when the environment contains non-ASCII characters. Known problems still remain, however, when the environment contains characters outside of the current ANSI codepage (e.g. see the item about Unicode in
%ENVin http://perl5.git.perl.org/perl.git/blob/HEAD:/Porting/todo.pod). [perl #113536]
Building perl with some Windows compilers used to fail due to a problem with miniperl's
globoperator (which uses the
perlglobprogram) deleting the PATH environment variable [perl #113798].
A new makefile option,
USE_64_BIT_INT, has been added to the Windows makefiles. Set this to "define" when building a 32-bit perl if you want it to use 64-bit integers.
Machine code size reductions, already made to the DLLs of XS modules in Perl v5.17.2, have now been extended to the perl DLL itself.
Building with VC++ 6.0 was inadvertently broken in Perl v5.17.2 but has now been fixed again.
Building on WinCE is now possible once again, although more work is required to fully restore a clean build.
Internal Changes
Synonyms for the misleadingly named
av_len()have been created:
av_tindex. All three of these return the number of the highest index in the array, not the number of elements it contains.
SvUPGRADE() is no longer an expression. Originally this macro (and its underlying function, sv_upgrade()) were documented as boolean, although in reality they always croaked on error and never returned false. In 2005 the documentation was updated to specify a void return value, but SvUPGRADE() was left always returning 1 for backwards compatibility. This has now been removed, and SvUPGRADE() is now a statement with no return value.
So this is now a syntax error:
if (!SvUPGRADE(sv)) { croak(...); }
If you have code like that, simply replace it with
or to avoid compiler warnings with older perls, possibly
Perl has a new copy-on-write mechanism that allows any SvPOK scalar to be upgraded to a copy-on-write scalar. A reference count on the string buffer is stored in the string buffer itself. This feature is not enabled by default.
It can be enabled in a perl build by running Configure with -Accflags=-DPERL_NEW_COPY_ON_WRITE, and we would encourage XS authors to try their code with such an enabled perl, and provide feedback. Unfortunately, there is not yet a good guide to updating XS code to cope with COW. Until such a document is available, consult the perl5-porters mailing list.
It breaks a few XS modules by allowing copy-on-write scalars to go through code paths that never encountered them before.
Copy-on-write no longer uses the SvFAKE and SvREADONLY flags. Hence, SvREADONLY indicates a true read-only SV.
Use the SvIsCOW macro (as before) to identify a copy-on-write scalar.
PL_glob_indexis gone.
The private Perl_croak_no_modify has had its context parameter removed. It is now has a void prototype. Users of the public API croak_no_modify remain unaffected.
Copy-on-write (shared hash key) scalars are no longer marked read-only.
SvREADONLYreturns false on such an SV, but
SvIsCOWstill returns true.
A new op type,
OP_PADRANGEhas been introduced. The perl peephole optimiser will, where possible, substitute a single padrange op for a pushmark followed by one or more pad ops, and possibly also skipping list and nextstate ops. In addition, the op can carry out the tasks associated with the RHS of a
my(...) = @_assignment, so those ops may be optimised away too.
Case-insensitive matching inside a [bracketed] character class with a multi-character fold no longer excludes one of the possibilities in the circumstances that it used to. [perl #89774].
PL_formfeedhas been removed.
The regular expression engine no longer reads one byte past the end of the target string. While for all internally well-formed scalars this should never have been a problem, this change facilitates clever tricks with string buffers in CPAN modules. [perl #73542]
Inside a BEGIN block,
PL_compcvnow points to the currently-compiling subroutine, rather than the BEGIN block itself.
mg_lengthhas been deprecated.
sv_lennow always returns a byte count and
sv_len_utf8a character count. Previously,
sv_len_utf8were both buggy and would sometimes returns bytes and sometimes characters.
sv_len_utf8no longer assumes that its argument is in UTF-8. Neither of these creates UTF-8 caches for tied or overloaded values or for non-PVs any more.
sv_mortalcopynow copies string buffers of shared hash key scalars when called from XS modules [perl #79824].
RXf_SKIPWHITEare no longer used. They are now #defined as 0.
The new
RXf_MODIFIES_VARSflag can be set by custom regular expression engines to indicate that the execution of the regular expression may cause variables to be modified. This lets
s///know to skip certain optimisations. Perl's own regular expression engine sets this flag for the special backtracking verbs that set $REGMARK and $REGERROR.
The APIs for accessing lexical pads have changed considerably.
PADLISTs are now longer
AVs, but their own type instead.
PADLISTs now contain a
PADand a
PADNAMEs, rather than
AVs for the pad and the list of pad names.
PADNAMELISTs, and
PADNAMEs are to be accessed as such through the newly added pad API instead of the plain
SVAPIs. See perlapi for details.
In the regex API, the numbered capture callbacks are passed an index indicating what match variable is being accessed. There are special index values for the
$`, $&, $&variables. Previously the same three values were used to retrieve
${^PREMATCH}, ${^MATCH}, ${^POSTMATCH}too, but these have now been assigned three separate values. See "Numbered capture callbacks" in perlreapi.
PL_sawampersandwas previously a boolean indicating that any of
$`, $&, $&had been seen; it now contains three one-bit flags indicating the presence of each of the variables individually.
CV *typemap entry now supports
&{}overloading and typeglobs, just like
&{...}[perl #96872].
SVf_AMAGICflag to indicate overloading is now on the stash, not the object. It is now set automatically whenever a method or @ISA changes, so its meaning has changed, too. It now means "potentially overloaded". When the overload table is calculated, the flag is automatically turned off if there is no overloading, so there should be no noticeable slowdown.
The staleness of the overload tables is now checked when overload methods are invoked, rather than during
"A" magic is gone. The changes to the handling of the
SVf_AMAGICflag eliminate the need for it.
PL_amagic_generationhas been removed as no longer necessary. For XS modules, it is now a macro alias to
The fallback overload setting is now stored in a stash entry separate from overloadedness itself.
The character-processing code has been cleaned up in places. The changes should be operationally invisible.
studyfunction was made a no-op in v5.16. It was simply disabled via a
returnstatement; the code was left in place. Now the code supporting what
studyused to do has been removed.
Under threaded perls, there is no longer a separate PV allocated for every COP to store its package name (
cop->stashpv). Instead, there is an offset (
cop->stashoff) into the new
PL_stashpadarray, which holds stash pointers.
In the pluggable regex API, the
regexp_enginestruct has acquired a new field
op_comp, which is currently just for perl's internal use, and should be initialized to NULL by other regex plugin modules.
A new function
alloccopstashhas been added to the API, but is considered experimental. See perlapi.
Perl used to implement get magic in a way that would sometimes hide bugs in code that could call mg_get() too many times on magical values. This hiding of errors no longer occurs, so long-standing bugs may become visible now. If you see magic-related errors in XS code, check to make sure it, together with the Perl API functions it uses, calls mg_get() only once on SvGMAGICAL() values.
OP allocation for CVs now uses a slab allocator. This simplifies memory management for OPs allocated to a CV, so cleaning up after a compilation error is simpler and safer [perl #111462][perl #112312].
PERL_DEBUG_READONLY_OPShas been rewritten to work with the new slab allocator, allowing it to catch more violations than before.
The old slab allocator for ops, which was only enabled for
PERL_DEBUG_READONLY_OPS, has been retired.
Selected Bug Fixes
Here-doc terminators no longer require a terminating newline character when they occur at the end of a file. This was already the case at the end of a string eval [perl #65838].
-DPERL_GLOBAL_STRUCTbuilds now free the global struct after they've finished using it.
A trailing '/' on a path in @INC will no longer have an additional '/' appended.
:crlflayer now works when unread data doesn't fit into its own buffer. [perl #112244].
ungetc()now handles UTF-8 encoded data. [perl #116322].
A bug in the core typemap caused any C types that map to the T_BOOL core typemap entry to not be set, updated, or modified when the T_BOOL variable was used in an OUTPUT: section with an exception for RETVAL. T_BOOL in an INPUT: section was not affected. Using a T_BOOL return type for an XSUB (RETVAL) was not affected. A side effect of fixing this bug is, if a T_BOOL is specified in the OUTPUT: section (which previous did nothing to the SV), and a read only SV (literal) is passed to the XSUB, croaks like "Modification of a read-only value attempted" will happen. [perl #115796]
On many platforms, providing a directory name as the script name caused perl to do nothing and report success. It should now universally report an error and exit nonzero. [perl #61362]
sort {undef} ...under fatal warnings no longer crashes. It had begun crashing in Perl v5.16.
Stashes blessed into each other (
bless \%Foo::, 'Bar'; bless \%Bar::, 'Foo') no longer result in double frees. This bug started happening in Perl v5.16.
Numerous memory leaks have been fixed, mostly involving fatal warnings and syntax errors.
Some failed regular expression matches such as
'f' =~ /../gwere not resetting
pos. Also, "match-once" patterns (
m?...?g) failed to reset it, too, when invoked a second time [perl #23180].
$&after a pattern match now works if it had not been seen before the match. I.e., this applies to
no strict) and
eval '$&'. The same applies to
$`[perl #4289].
Several bugs involving
local *ISAand
local *Foo::causing stale MRO caches have been fixed.
Defining a subroutine when its typeglob has been aliased no longer results in stale method caches. This bug was introduced in Perl v5.10.
Localising a typeglob containing a subroutine when the typeglob's package has been deleted from its parent stash no longer produces an error. This bug was introduced in Perl v5.14.
Under some circumstances,
local *method=...would fail to reset method caches upon scope exit.
/[.foo.]/is no longer an error, but produces a warning (as before) and is treated as
/[.fo]/[perl #115818].
goto $tied_varnow calls FETCH before deciding what type of goto (subroutine or label) this is.
Renaming packages through glob assignment (
*Foo:: = *Bar::; *Bar:: = *Baz::) in combination with
resetno longer makes threaded builds crash.
A number of bugs related to assigning a list to hash have been fixed. Many of these involve lists with repeated keys like
(1, 1, 1, 1).
The expression
scalar(%h = (1, 1, 1, 1))now returns
4, not
The return value of
%h = (1, 1, 1)in list context was wrong. Previously this would return
(1, undef, 1), now it returns
(1, undef).
Perl now issues the same warning on
($s, %h) = (1, {})as it does for
(%h) = ({}), "Reference found where even-sized list expected".
A number of additional edge cases in list assignment to hashes were corrected. For more details see commit 23b7025ebc.
Attributes applied to lexical variables no longer leak memory. [perl #114764]
requirefollowed by a bareword (or version) and then an infix operator is no longer a syntax error. It used to be for those infix operators (like
+) that have a different meaning where a term is expected. [perl #105924]
require a::b . 1and
require a::b + 1no longer produce erroneous ambiguity warnings. [perl #107002]
Class method calls are now allowed on any string, and not just strings beginning with an alphanumeric character. [perl #105922]
An empty pattern created with
qr//used in
m///no longer triggers the "empty pattern reuses last pattern" behaviour. [perl #96230]
Tying a hash during iteration no longer results in a memory leak.
Freeing a tied hash during iteration no longer results in a memory leak.
List assignment to a tied array or hash that dies on STORE no longer results in a memory leak.
If the hint hash (
%^H) is tied, compile-time scope entry (which copies the hint hash) no longer leaks memory if FETCH dies. [perl #107000]
Constant folding no longer inappropriately triggers the special
split " "behaviour. [perl #94490]
defined scalar(@array),
defined do { &foo }, and similar constructs now treat the argument to
definedas a simple scalar. [perl #97466]
Running a custom debugging that defines no
*DB::DBglob or provides a subroutine stub for
&DB::DBno longer results in a crash, but an error instead. [perl #114990]
reset ""now matches its documentation.
resetonly resets
m?...?patterns when called with no argument. An empty string for an argument now does nothing. (It used to be treated as no argument.) [perl #97958]
printfwith an argument returning an empty list no longer reads past the end of the stack, resulting in erratic behaviour. [perl #77094]
--subnameno longer produces erroneous ambiguity warnings. [perl #77240]
v10is now allowed as a label or package name. This was inadvertently broken when v-strings were added in Perl v5.6. [perl #56880]
sprintfcould be confused by ties, overloading, references and typeglobs if the stringification of such changed the internal representation to or from UTF-8. [perl #114410]
utf8::encode now calls FETCH and STORE on tied variables. utf8::decode now calls STORE (it was already calling FETCH).
$tied =~ s/$non_utf8/$utf8/no longer loops infinitely if the tied variable returns a Latin-1 string, shared hash key scalar, or reference or typeglob that stringifies as ASCII or Latin-1. This was a regression from v5.12.
s///without /e is now better at detecting when it needs to forego certain optimisations, fixing some buggy cases:
Match variables in certain constructs (
..and others) in the replacement part; e.g.,
s/(.)/$l{$a||$1}/g. [perl #26986]
Aliases to match variables in the replacement.
$REGMARKin the replacement. [perl #49190]
An empty pattern (
s//$foo/) that causes the last-successful pattern to be used, when that pattern contains code blocks that modify the variables in the replacement.
The taintedness of the replacement string no longer affects the taintedness of the return value of
$|autoflush variable is created on-the-fly when needed. If this happened (e.g., if it was mentioned in a module or eval) when the currently-selected filehandle was a typeglob with an empty IO slot, it used to crash. [perl #115206]
Line numbers at the end of a string eval are no longer off by one. [perl #114658]
@INC filters (subroutines returned by subroutines in @INC) that set $_ to a copy-on-write scalar no longer cause the parser to modify that string buffer in place.
length($object)no longer returns the undefined value if the object has string overloading that returns undef. [perl #115260]
The use of
PL_stashcache, the stash name lookup cache for method calls, has been restored,
Commit da6b625f78f5f133 in August 2011 inadvertently broke the code that looks up values in
PL_stashcache. As it's a only cache, quite correctly everything carried on working without it.
The error "Can't localize through a reference" had disappeared in v5.16.0 when
local %$refappeared on the last line of an lvalue subroutine. This error disappeared for
\local %$refin perl v5.8.1. It has now been restored.
The parsing of here-docs has been improved significantly, fixing several parsing bugs and crashes and one memory leak, and correcting wrong subsequent line numbers under certain conditions.
Inside an eval, the error message for an unterminated here-doc no longer has a newline in the middle of it [perl #70836].
A substitution inside a substitution pattern (
s/${s|||}//) no longer confuses the parser.
It may be an odd place to allow comments, but
s//"" # hello/ehas always worked, unless there happens to be a null character before the first #. Now it works even in the presence of nulls.
An invalid range in
y///no longer results in a memory leak.
String eval no longer treats a semicolon-delimited quote-like operator at the very end (
eval 'q;;') as a syntax error.
warn {$_ => 1} + 1is no longer a syntax error. The parser used to get confused with certain list operators followed by an anonymous hash and then an infix operator that shares its form with a unary operator.
(caller $n)[6](which gives the text of the eval) used to return the actual parser buffer. Modifying it could result in crashes. Now it always returns a copy. The string returned no longer has "\n;" tacked on to the end. The returned text also includes here-doc bodies, which used to be omitted.
Reset the UTF-8 position cache when accessing magical variables to avoid the string buffer and the UTF-8 position cache getting out of sync [perl #114410].
Various cases of get magic being called twice for magical UTF-8 strings have been fixed.
This code (when not in the presence of
$_ = 'x' x 1_000_000; 1 while /(.)/;
used to skip the buffer copy for performance reasons, but suffered from
$1etc changing if the original string changed. That's now been fixed.
Perl doesn't use PerlIO anymore to report out of memory messages, as PerlIO might attempt to allocate more memory.
In a regular expression, if something is quantified with
n > m, it can't possibly match. Previously this was a fatal error, but now is merely a warning (and that something won't match). [perl #82954].
It used to be possible for formats defined in subroutines that have subsequently been undefined and redefined to close over variables in the wrong pad (the newly-defined enclosing sub), resulting in crashes or "Bizarre copy" errors.
Redefinition of XSUBs at run time could produce warnings with the wrong line number.
The %vd sprintf format does not support version objects for alpha versions. It used to output the format itself (%vd) when passed an alpha version, and also emit an "Invalid conversion in printf" warning. It no longer does, but produces the empty string in the output. It also no longer leaks memory in this case.
$obj->SUPER::methodcalls in the main package could fail if the SUPER package had already been accessed by other means.
Stash aliasing (
*foo:: = *bar::) no longer causes SUPER calls to ignore changes to methods or @ISA or use the wrong package.
Method calls on packages whose names end in ::SUPER are no longer treated as SUPER method calls, resulting in failure to find the method. Furthermore, defining subroutines in such packages no longer causes them to be found by SUPER method calls on the containing package [perl #114924].
\wnow matches the code points U+200C (ZERO WIDTH NON-JOINER) and U+200D (ZERO WIDTH JOINER).
\Wno longer matches these. This change is because Unicode corrected their definition of what
\wshould match.
dump LABELno longer leaks its label.
Constant folding no longer changes the behaviour of functions like
truncate()that can take either filenames or handles.
stat 1 ? foo : barnows treats its argument as a file name (since it is an arbitrary expression), rather than the handle "foo".
truncate FOO, $lenno longer falls back to treating "FOO" as a file name if the filehandle has been deleted. This was broken in Perl v5.16.0.
Subroutine redefinitions after sub-to-glob and glob-to-glob assignments no longer cause double frees or panic messages.
s///now turns vstrings into plain strings when performing a substitution, even if the resulting string is the same (
Prototype mismatch warnings no longer erroneously treat constant subs as having no prototype when they actually have "".
Constant subroutines and forward declarations no longer prevent prototype mismatch warnings from omitting the sub name.
undefon a subroutine now clears call checkers.
refoperator started leaking memory on blessed objects in Perl v5.16.0. This has been fixed [perl #114340].
useno longer tries to parse its arguments as a statement, making
use constant { () };a syntax error [perl #114222].
On debugging builds, "uninitialized" warnings inside formats no longer cause assertion failures.
On debugging builds, subroutines nested inside formats no longer cause assertion failures [perl #78550].
Formats and
usestatements are now permitted inside formats.
print $xand
sub { print $x }->()now always produce the same output. It was possible for the latter to refuse to close over $x if the variable was not active; e.g., if it was defined outside a currently-running named subroutine.
print $xand
print eval '$x'now produce the same output. This also allows "my $x if 0" variables to be seen in the debugger [perl #114018].
Formats called recursively no longer stomp on their own lexical variables, but each recursive call has its own set of lexicals.
Attempting to free an active format or the handle associated with it no longer results in a crash.
Format parsing no longer gets confused by braces, semicolons and low-precedence operators. It used to be possible to use braces as format delimiters (instead of
.), but only sometimes. Semicolons and low-precedence operators in format argument lines no longer confuse the parser into ignoring the line's return value. In format argument lines, braces can now be used for anonymous hashes, instead of being treated always as
Formats can now be nested inside code blocks in regular expressions and other quoted constructs (
qq/${...}/) [perl #114040].
Formats are no longer created after compilation errors.
Under debugging builds, the -DA command line option started crashing in Perl v5.16.0. It has been fixed [perl #114368].
A potential deadlock scenario involving the premature termination of a pseudo- forked child in a Windows build with ithreads enabled has been fixed. This resolves the common problem of the t/op/fork.t test hanging on Windows [perl #88840].
The code which generates errors from
require()could potentially read one or two bytes before the start of the filename for filenames less than three bytes long and ending
/\.p?\z/. This has now been fixed. Note that it could never have happened with module names given to
The handling of pathnames of modules given to
require()has been made thread-safe on VMS.
Non-blocking sockets have been fixed on VMS.
A bug in the compilation of a
/(?{})/expression which affected the TryCatch test suite has been fixed [perl #114242].
Pod can now be nested in code inside a quoted construct outside of a string eval. This used to work only within string evals [perl #114040].
goto ''now looks for an empty label, producing the "goto must have label" error message, instead of exiting the program [perl #111794].
goto "\0"now dies with "Can't find label" instead of "goto must have label".
The C function
hv_storeused to result in crashes when used on
%^H[perl #111000].
A call checker attached to a closure prototype via
cv_set_call_checkeris now copied to closures cloned from it. So
cv_set_call_checkernow works inside an attribute handler for a closure.
Writing to
$^Nused to have no effect. Now it croaks with "Modification of a read-only value" by default, but that can be overridden by a custom regular expression engine, as with
$1[perl #112184].
undefon a control character glob (
undef *^H) no longer emits an erroneous warning about ambiguity [perl #112456].
For efficiency's sake, many operators and built-in functions return the same scalar each time. Lvalue subroutines and subroutines in the CORE:: namespace were allowing this implementation detail to leak through.
print &CORE::uc("a"), &CORE::uc("b")used to print "BB". The same thing would happen with an lvalue subroutine returning the return value of
uc. Now the value is copied in such cases.
method {}syntax with an empty block or a block returning an empty list used to crash or use some random value left on the stack as its invocant. Now it produces an error.
vecnow works with extremely large offsets (>2 GB) [perl #111730].
Changes to overload settings now take effect immediately, as do changes to inheritance that affect overloading. They used to take effect only after
Objects that were created before a class had any overloading used to remain non-overloaded even if the class gained overloading through
use overloador @ISA changes, and even after
bless. This has been fixed [perl #112708].
Classes with overloading can now inherit fallback values.
Overloading was not respecting a fallback value of 0 if there were overloaded objects on both sides of an assignment operator like
+=[perl #111856].
posnow croaks with hash and array arguments, instead of producing erroneous warnings.
while(each %h)now implies
while(defined($_ = each %h)), like
Subs in the CORE:: namespace no longer crash after
undef *_when called with no argument list (
&CORE::timewith no parentheses).
unpackno longer produces the "'/' must follow a numeric type in unpack" error when it is the data that are at fault [perl #60204].
"@array"now call FETCH only once on a tied
$"[perl #8931].
Some subroutine calls generated by compiling core ops affected by a
CORE::GLOBALoverride had op checking performed twice. The checking is always idempotent for pure Perl code, but the double checking can matter when custom call checkers are involved.
A race condition used to exist around fork that could cause a signal sent to the parent to be handled by both parent and child. Signals are now blocked briefly around fork to prevent this from happening [perl #82580].
The implementation of code blocks in regular expressions, such as
(??{}), has been heavily reworked to eliminate a whole slew of bugs. The main user-visible changes are:
Code blocks within patterns are now parsed in the same pass as the surrounding code; in particular it is no longer necessary to have balanced braces: this now works:
/(?{ $x='{' })/
This means that this error message is no longer generated:
Sequence (?{...}) not terminated or not {}-balanced in regex
but a new error may be seen:
Sequence (?{...}) not terminated with ')'
In addition, literal code blocks within run-time patterns are only compiled once, at perl compile-time:
for my $p (...) { # this 'FOO' block of code is compiled once, # at the same time as the surrounding 'for' loop /$p{(?{FOO;})/; }
Lexical variables are now sane as regards scope, recursion and closure behavior. In particular,
/A(?{B})C/behaves (from a closure viewpoint) exactly like
/A/ && do { B } && /C/, while
qr/A(?{B})C/is like
sub {/A/ && do { B } && /C/}. So this code now works how you might expect, creating three regexes that match 0, 1, and 2:
for my $i (0..2) { push @r, qr/^(??{$i})$/; } "1" =~ $r[1]; # matches
use re 'eval'pragma is now only required for code blocks defined at runtime; in particular in the following, the text of the
$rpattern is still interpolated into the new pattern and recompiled, but the individual compiled code-blocks within
$rare reused rather than being recompiled, and
use re 'eval'isn't needed any more:
my $r = qr/abc(?{....})def/; /xyz$r/;
Flow control operators no longer crash. Each code block runs in a new dynamic scope, so
nextetc. will not see any enclosing loops.
returnreturns a value from the code block, not from any enclosing subroutine.
Perl normally caches the compilation of run-time patterns, and doesn't recompile if the pattern hasn't changed, but this is now disabled if required for the correct behavior of closures. For example:
my $code = '(??{$x})'; for my $x (1..3) { # recompile to see fresh value of $x each time $x =~ /$code/; }
(?msix)etc. flags are now propagated into the return value from
(??{}); this now works:
"AB" =~ /a(??{'b'})/i;
Warnings and errors will appear to come from the surrounding code (or for run-time code blocks, from an eval) rather than from an
use re 'eval'; $c = '(?{ warn "foo" })'; /$c/; /(?{ warn "foo" })/;
formerly gave:
foo at (re_eval 1) line 1. foo at (re_eval 2) line 1.
and now gives:
foo at (eval 1) line 1. foo at /some/prog line 2.
Perl now can be recompiled to use any Unicode version. In v5.16, it worked on Unicodes 6.0 and 6.1, but there were various bugs if earlier releases were used; the older the release the more problems.
vecno longer produces "uninitialized" warnings in lvalue context [perl #9423].
An optimization involving fixed strings in regular expressions could cause a severe performance penalty in edge cases. This has been fixed [perl #76546].
In certain cases, including empty subpatterns within a regular expression (such as
(?:|)) could disable some optimizations. This has been fixed.
The "Can't find an opnumber" message that
prototypeproduces when passed a string like "CORE::nonexistent_keyword" now passes UTF-8 and embedded NULs through unchanged [perl #97478].
prototypenow treats magical variables like
$1the same way as non-magical variables when checking for the CORE:: prefix, instead of treating them as subroutine names.
Under threaded perls, a runtime code block in a regular expression could corrupt the package name stored in the op tree, resulting in bad reads in
caller, and possibly crashes [perl #113060].
Referencing a closure prototype (
\&{$_[1]}in an attribute handler for a closure) no longer results in a copy of the subroutine (or assertion failures on debugging builds).
eval '__PACKAGE__'now returns the right answer on threaded builds if the current package has been assigned over (as in
*ThisPackage:: = *ThatPackage::) [perl #78742].
If a package is deleted by code that it calls, it is possible for
callerto see a stack frame belonging to that deleted package.
callercould crash if the stash's memory address was reused for a scalar and a substitution was performed on the same scalar [perl #113486].
UNIVERSAL::canno longer treats its first argument differently depending on whether it is a string or number internally.
<&for the mode checks to see whether the third argument is a number, in determining whether to treat it as a file descriptor or a handle name. Magical variables like
$1were always failing the numeric check and being treated as handle names.
warn's handling of magical variables (
$1, ties) has undergone several fixes.
FETCHis only called once now on a tied argument or a tied
$@[perl #97480]. Tied variables returning objects that stringify as "" are no longer ignored. A tied
$@that happened to return a reference the previous time it was used is no longer ignored.
warn ""now treats
$@with a number in it the same way, regardless of whether it happened via
$@="3". It used to ignore the former. Now it appends "\t...caught", as it has always done with
Numeric operators on magical variables (e.g.,
$1 + 1) used to use floating point operations even where integer operations were more appropriate, resulting in loss of accuracy on 64-bit platforms [perl #109542].
Unary negation no longer treats a string as a number if the string happened to be used as a number at some point. So, if
$xcontains the string "dogs",
-$xreturns "-dogs" even if
$y=0+$xhas happened at some point.
In Perl v5.14,
-'-10'was fixed to return "10", not "+10". But magical variables (
$1, ties) were not fixed till now [perl #57706].
Unary negation now treats strings consistently, regardless of the internal
A regression introduced in Perl v5.16.0 involving
tr/SEARCHLIST/REPLACEMENTLIST/has been fixed. Only the first instance is supposed to be meaningful if a character appears more than once in
SEARCHLIST. Under some circumstances, the final instance was overriding all earlier ones. [perl #113584]
Regular expressions like
qr/\87/previously silently inserted a NUL character, thus matching as if it had been written
qr/\00087/. Now it matches as if it had been written as
qr/87/, with a message that the sequence
"\8"is unrecognized.
__SUB__now works in special blocks (
END, etc.).
Thread creation on Windows could theoretically result in a crash if done inside a
BEGINblock. It still does not work properly, but it no longer crashes [perl #111610].
\&{''}(with the empty string) now autovivifies a stub like any other sub name, and no longer produces the "Unable to create sub" error [perl #94476].
A regression introduced in v5.14.0 has been fixed, in which some calls to the
remodule would clobber
$_[perl #113750].
do FILEnow always either sets or clears
$@, even when the file can't be read. This ensures that testing
$@first (as recommended by the documentation) always returns the correct result.
The array iterator used for the
each @arrayconstruct is now correctly reset when
@arrayis cleared [perl #75596]. This happens, for example, when the array is globally assigned to, as in
@array = (...), but not when its values are assigned to. In terms of the XS API, it means that
av_clear()will now reset the iterator.
This mirrors the behaviour of the hash iterator when the hash is cleared.
$class->isa, and
$class->DOESnow return correct results, regardless of whether that package referred to by
$classexists [perl #47113].
Arriving signals no longer clear
$@[perl #45173].
my ()declarations with an empty variable list [perl #113554].
During parsing, subs declared after errors no longer leave stubs [perl #113712].
Closures containing no string evals no longer hang on to their containing subroutines, allowing variables closed over by outer subroutines to be freed when the outer sub is freed, even if the inner sub still exists [perl #89544].
Duplication of in-memory filehandles by opening with a "<&=" or ">&=" mode stopped working properly in v5.16.0. It was causing the new handle to reference a different scalar variable. This has been fixed [perl #113764].
qr//expressions no longer crash with custom regular expression engines that do not set
offsat regular expression compilation time [perl #112962].
delete localno longer crashes with certain magical arrays and hashes [perl #112966].
localon elements of certain magical arrays and hashes used not to arrange to have the element deleted on scope exit, even if the element did not exist before
scalar(write)no longer returns multiple items [perl #73690].
String to floating point conversions no longer misparse certain strings under
use locale[perl #109318].
@INCfilters that die no longer leak memory [perl #92252].
The implementations of overloaded operations are now called in the correct context. This allows, among other things, being able to properly override
<>[perl #47119].
Specifying only the
fallbackkey when calling
use overloadnow behaves properly [perl #113010].
sub foo { my $a = 0; while ($a) { ... } }and
sub foo { while (0) { ... } }now return the same thing [perl #73618].
String negation now behaves the same under
use integer;as it does without [perl #113012].
chrnow returns the Unicode replacement character (U+FFFD) for -1, regardless of the internal representation. -1 used to wrap if the argument was tied or a string internally.
Using a
formatafter its enclosing sub was freed could crash as of perl v5.12.0, if the format referenced lexical variables from the outer sub.
Using a
formatafter its enclosing sub was undefined could crash as of perl v5.10.0, if the format referenced lexical variables from the outer sub.
Using a
formatdefined inside a closure, which format references lexical variables from outside, never really worked unless the
writecall was directly inside the closure. In v5.10.0 it even started crashing. Now the copy of that closure nearest the top of the call stack is used to find those variables.
Formats that close over variables in special blocks no longer crash if a stub exists with the same name as the special block before the special block is compiled.
The parser no longer gets confused, treating
eval foo ()as a syntax error if preceded by
print;[perl #16249].
The return value of
syscallis no longer truncated on 64-bit platforms [perl #113980].
Constant folding no longer causes
print 1 ? FOO : BARto print to the FOO handle [perl #78064].
do subnamenow calls the named subroutine and uses the file name it returns, instead of opening a file named "subname".
Subroutines looked up by rv2cv check hooks (registered by XS modules) are now taken into consideration when determining whether
foo barshould be the sub call
foo(bar)or the method call
CORE::foo::baris no longer treated specially, allowing global overrides to be called directly via
CORE::GLOBAL::uc(...)[perl #113016].
Calling an undefined sub whose typeglob has been undefined now produces the customary "Undefined subroutine called" error, instead of "Not a CODE reference".
Two bugs involving @ISA have been fixed.
*ISA = *glob_without_arrayand
undef *ISA; @{*ISA}would prevent future modifications to @ISA from updating the internal caches used to look up methods. The *glob_without_array case was a regression from Perl v5.12.
Regular expression optimisations sometimes caused
/mto produce failed or incorrect matches [perl #114068].
__SUB__now works in a
sortblock when the enclosing subroutine is predeclared with
sub foo;syntax [perl #113710].
Unicode properties only apply to Unicode code points, which leads to some subtleties when regular expressions are matched against above-Unicode code points. There is a warning generated to draw your attention to this. However, this warning was being generated inappropriately in some cases, such as when a program was being parsed. Non-Unicode matches such as
[:word;]should not generate the warning, as their definitions don't limit them to apply to only Unicode code points. Now the message is only generated when matching against
\P{}. There remains a bug, [perl #114148], for the very few properties in Unicode that match just a single code point. The warning is not generated if they are matched against an above-Unicode code point.
Uninitialized warnings mentioning hash elements would only mention the element name if it was not in the first bucket of the hash, due to an off-by-one error.
A regular expression optimizer bug could cause multiline "^" to behave incorrectly in the presence of line breaks, such that
"/\n\n" =~ m#\A(?:^/$)#imwould not match [perl #115242].
forkin list context no longer corrupts the stack.
@a = (1, 2, fork, 3)used to gobble up the 2 and assign
(1, undef, 3)if the
forkcall failed.
Numerous memory leaks have been fixed, mostly involving tied variables that die, regular expression character classes and code blocks, and syntax errors.
Assigning a regular expression (
${qr//}) to a variable that happens to hold a floating point number no longer causes assertion failures on debugging builds.
Assigning a regular expression to a scalar containing a number no longer causes subsequent numification to produce random numbers.
Assigning a regular expression to a magic variable no longer wipes away the magic. This was a regression from v5.10.
Assigning a regular expression to a blessed scalar no longer results in crashes. This was also a regression from v5.10.
Regular expression can now be assigned to tied hash and array elements with flattening into strings.
Numifying a regular expression no longer results in an uninitialized warning.
Negative array indices no longer cause EXISTS methods of tied variables to be ignored. This was a regression from v5.12.
Negative array indices no longer result in crashes on arrays tied to non-objects.
$byte_overload .= $utf8no longer results in doubly-encoded UTF-8 if the left-hand scalar happened to have produced a UTF-8 string the last time overloading was invoked.
goto &subnow uses the current value of @_, instead of using the array the subroutine was originally called with. This means
local @_ = (...); goto &subnow works [perl #43077].
If a debugger is invoked recursively, it no longer stomps on its own lexical variables. Formerly under recursion all calls would share the same set of lexical variables [perl #115742].
*_{ARRAY}returned from a subroutine no longer spontaneously becomes empty.
Known Problems
There are no known regressions. Please report any bugs you find!
Perl v5.18.0 represents approximately 12 months of development since Perl v5.16.0 and contains approximately 400,000 lines of changes across 2,100 files from 113 authors.
Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl v5.18.0:
Aaron Crane, Aaron Trevena, Abhijit Menon-Sen, Adrian M. Enache, Alan Haggai Alavi, Alexandr Ciornii, Andrew Tam, Andy Dougherty, Anton Nikishaev, Aristotle Pagaltzis, Augustina Blair, Bob Ernst, Brad Gilbert, Breno G. de Oliveira, Brian Carlson, Brian Fraser, Charlie Gonzalez, Chip Salzenberg, Chris 'BinGOs' Williams, Christian Hansen, Colin Kuskie, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, Daniel Perrett, Darin McBride, Dave Rolsky, David Golden, David Leadbeater, David Mitchell, David Nicol, Dominic Hargreaves, E. Choroba, Eric Brine, Evan Miller, Father Chrysostomos, Florian Ragwitz, François Perrad, George Greer, Goro Fuji, H.Merijn Brand, Herbert Breunung, Hugo van der Sanden, Igor Zaytsev, James E Keenan, Jan Dubois, Jasmine Ahuja, Jerry D. Hedden, Jess Robinson, Jesse Luehrs, Joaquin Ferrero, Joel Berger, John Goodyear, John Peacock, Karen Etheridge, Karl Williamson, Karthik Rajagopalan, Kent Fredric, Leon Timmermans, Lucas Holt, Lukas Mai, Marcus Holland-Moritz, Markus Jansen, Martin Hasch, Matthew Horsfall, Max Maischein, Michael G Schwern, Michael Schroeder, Moritz Lenz, Nicholas Clark, Niko Tyni, Oleg Nesterov, Patrik Hägglund, Paul Green, Paul Johnson, Paul Marquess, Peter Martini, Rafael Garcia-Suarez, Reini Urban, Renee Baecker, Rhesa Rozendaal, Ricardo Signes, Robin Barker, Ronald J. Kimball, Ruslan Zakirov, Salvador Fandiño, Sawyer X, Scott Lanning, Sergey Alekseev, Shawn M Moore, Shirakata Kentaro, Shlomi Fish, Sisyphus, Smylers, Steffen Müller, Steve Hay, Steve Peters, Steven Schubiger, Sullivan Beck, Sven Strickroth, Sébastien Aperghis-Tramoni, Thomas Sibley, Tobias Leich, Tom Wyant, Tony Cook, Vadim Konovalov, Vincent Pit, Volker Schatz, Walt Mankowski, Yves Orton, Zefram.
The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.
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@example.com 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@example.com. This points to a closed subscription unarchived mailing list, which includes all the core committers, who will be able to help assess the impact of issues, figure out a resolution, and help co-ordinate the release of patches to mitigate or fix the problem across all platforms on which Perl is supported. Please only use this address for security issues in the Perl core, not for modules independently distributed on CPAN.
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.


text:
TALLADEGA, Ala. -- Kyle Busch apologized Thursday to manufacturer Toyota Motor Corp. for his profanity-laced rant about the fuel mileage at Dover.
Busch had to make a late stop in Sunday's race that he believed cost him the win. Joe Gibbs Racing teammate Denny Hamlin also had to stop for gas, but winner Brad Keselowski in a Dodge and Jimmie Johnson in a Chevrolet got better mileage and didn't have to stop.
Busch unleashed a string of profanities directed at Toyota on his in-car radio, and did not do media interviews after the race.
In a statement issued Thursday by both JGR and Toyota, Busch said his comments were "misguided."
"I made some remarks out of frustration on my radio at the end of last weekend's race in Dover that were very misguided," Busch said. "I owe my friends at Toyota and TRD an apology. We have a great partnership with TRD and they built me a motor that helped me lead over 300 laps and nearly lap the field.
"It's just frustrating that the caution fell where it did and suddenly it became a fuel mileage race and we were set up for maximum horsepower. Obviously, that worked well for most of the day and you can't control when the cautions will fall."
Busch has suffered several engine failures this season, and he missed a spot in the Chase for the Sprint Cup championship by just three points.
Still, TRD president Lee White was not pleased with Busch's comments Sunday.
But he seemed to understand Busch's frustration in the statement released Thursday, but has pointed out that JGR chose to go with engines heavy on horsepower at the expense of fuel mileage at Dover
"Kyle's had a frustrating year with several car and engine mechanical failures which were not his responsibility, and we're working extremely hard on our end to improve our products and processes," White said. "We will continue to address these issues, but we're ready to put this behind us and move forward with the remainder of the season, including the Toyota drivers battling for the championship."
Busch had to pit for fuel with 11 laps remaining after leading 302 of the scheduled 400-lap race. Keselowski went the final 89 laps without stopping for gas.
Team owner Joe Gibbs said in Thursday's statement the organization appreciates its relationship with Toyota, and that Busch shouldn't have cursed at the manufacturer.
"Kyle recognizes that his comments and the tone of his comments were misguided. We've been able to work through this issue and I think everyone is ready to get back to the focus being on racing and Talladega," Gibbs said.

subset: commoncrawl


text:
Ginger, Coriander & Orange Braised Chicken
I teased about this awesome package that I got and asked for several testers to help out with product testing. Thank you to the 15 testers to responded! I sent each of them 1-3 samples of tsp spices, and they each cooked with the spice and gave me a short 2 sentence review.
You guys rock.
What is tsp?
tsp spices are organic spices in perfectly measured, freshly sealed, single-use packages. Each tin comes with 12 spice packets – each 1 tsp of the spice. Their products, "packets of pure adventure," make measuring spoons obsolete and also protect spices from light and air to ensure freshness and the fullest flavor. A reprieve from spice cabinet chaos, these one-teaspoon spice packets are stored in tin cans that look great displayed on the kitchen counter, which makes them a perfect gift for home cooks.
Dried spices lose their potency after 6-12 months and the more light and air that gets exposed to the spice, the shorter the shelf life. Simply put, if you've still got that ground ginger in the back of your pantry, inherited from old Aunt Martha, your food is gonna taste like…well…crusty Aunt Martha. Nasty. I love the concept of tsp, because I only open what I need. the rest stays fresh and sealed.
(photo from tsp spices)
Such fancy packaging…are they expensive?
$7-$9 a box (12 tsp per box) – which is about 30% more than I pay for non-organic supermarket spice. However, I've learned something this year. Rather than go find the best deal possible, I've decided that I want to buy less and splurge on things that are beautiful, lovely to use and good for my family. I want to really savor and enjoy the things I have in my home, especially in the kitchen. Let me tell you, these spices are gorgeous.
Actually, when I first opened the package, I said out loud to Scott, "Damn. All this packaging – so wasteful! What's the point of organic spices if you're going to waste earth's resources for the packaging?"
And of course, Scott replied, "Stop bitching. Reuse the boxes." So now my boys' matchbox cars smell like Oregano.
read on….I'm giving some tsp spice tins away!!!
What did I make with the tsp spices?
The most awesome braised chicken ever. Oranges, garlic, and a blend of tsp ginger and coriander.
Ginger, Coriander and Orange Braised Chicken
Inspired by flipping through Nigel Slater's Appetite which has been sitting on my desk for the past 2 weeks because I can't stop looking at it. I love his style of cooking – "a small handful of crabmeat per person" "ginger root – a small lump." Nigel's book teaches you how to improvise and create a dish all your own. Forget following recipes word-for-word, he gives you a template and teaches you which flavor combinations work well and when is it done.
Each recipe also has variations at the end. The "Chicken, Garlic and Herbs" recipe (this is the recipe my Ginger, Coriander and Orange Braised Chicken is based on) has options for:
- a buttery finish
- a creamy finish
- use this same recipe to cook lamb with garlic and lemon
- or even pork steaks with apple and creme
Anyways, I highly recommend this book. And hey, if Jamie Oliver says, "Nigel is a genius" then I'm totally sold.
You can substitute skin-on chicken breasts for thigh. Cut back the simmer time just a bit as the breast will cook faster than the bone-in thigh. Best to check it around the 17 minute mark, timing really will depend on how big and thick your breasts are.
6 chicken thighs, skin-on
1 oranges, cut into 8 wedges
6 cloves garlic, smashed with side of cleaver
1 tsp ground ginger
1 tsp ground coriander
2 tsp kosher salt
fresh ground pepper
1/2 cup white wine
2 1/2 tsp soy sauce
cilantro to garnish
In a small bowl, combine the ginger, coriander, salt and pepper. Season chicken on both sides with the spice mixture. Let sit at room temperature for 30 minutes or overnight in the refrigerator. In large dutch oven or deep skillet, heat 1 tbl olive oil on high heat. When hot, place the chicken, skin side down to brown for 1-2 minutes. Turn skin side up. Turn heat to low, throw in garlic and 4 orange sections (give a nice squeeze as you throw them in to get the juice in the pan). Add wine. Cover and simmer on gentle, low heat for 25 minutes or until chicken is cooked through. Remove chicken to plate, leaving the sauce in the pan. Remove and discard oranges, and add the remaining fresh orange wedges. Turn heat to medium-high and add soy sauce. Cook for 3 minutes until thickened. Pour on top of chicken, garnish with fresh cilantro.
Free tsp spices
Really! Just for you! tsp is sending me 3 twin packs. So, 3 lucky ducks will get a beautiful set of spices.
How to enter
Just comment below and tell me what is your favorite spice combination? That's it! If you want to link to one of your recipes, feel free to link away.
Contest is open until Saturday March 1st at 10pm est. I'll take entries up until then and we'll pick 3 winners using the nifty random number generator.
That's it! Good luck!
My tester's reviews
are on the next page!