perl5220delta - what is new for perl v5.22.0
This document describes differences between the 5.20.0 release and the 5.22.0 release.
If you are upgrading from an earlier release such as 5.18.0, first read perl5200delta, which describes differences between 5.18.0 and 5.20.0.
A new experimental facility has been added that makes the four standard bitwise operators (& | ^ ~) treat their operands consistently as numbers, and introduces four new dotted operators (&. |. ^. ~.) that treat their operands consistently as strings. The same applies to the assignment variants (&= |= ^= &.= |.= ^.=).
To use this, enable the "bitwise" feature and disable the "experimental::bitwise" warnings category. See "Bitwise String Operators" in perlop for details. [GH #14348].
<<>> is like <> but uses three-argument open to open each file in @ARGV. This means that each element of @ARGV will be treated as an actual file name, and "|foo" won't be treated as a pipe open.
\b boundaries in regular expressionsqr/\b{gcb}/
gcb stands for Grapheme Cluster Boundary. It is a Unicode property that finds the boundary between sequences of characters that look like a single character to a native speaker of a language. Perl has long had the ability to deal with these through the \X regular escape sequence. Now, there is an alternative way of handling these. See "\b{}, \b, \B{}, \B" in perlrebackslash for details.
qr/\b{wb}/
wb stands for Word Boundary. It is a Unicode property that finds the boundary between words. This is similar to the plain \b (without braces) but is more suitable for natural language processing. It knows, for example, that apostrophes can occur in the middle of words. See "\b{}, \b, \B{}, \B" in perlrebackslash for details.
qr/\b{sb}/
sb stands for Sentence Boundary. It is a Unicode property to aid in parsing natural language sentences. See "\b{}, \b, \B{}, \B" in perlrebackslash for details.
Regular expressions now support a /n flag that disables capturing and filling in $1, $2, etc inside of groups:
"hello" =~ /(hi|hello)/n; # $1 is not set
This is equivalent to putting ?: at the beginning of every capturing group.
See "n" in perlre for more information.
use re 'strict'
This applies stricter syntax rules to regular expression patterns compiled within its scope. This will hopefully alert you to typos and other unintentional behavior that backwards-compatibility issues prevent us from reporting in normal regular expression compilations. Because the behavior of this is subject to change in future Perl releases as we gain experience, using this pragma will raise a warning of category experimental::re_strict. See 'strict' in re.
For details on what is in this release, see http://www.unicode.org/versions/Unicode7.0.0/. The version of Unicode 7.0 that comes with Perl includes a correction dealing with glyph shaping in Arabic (see http://www.unicode.org/errata/#current_errata).
use locale
It is now possible to pass a parameter to use locale
On platforms that are able to handle POSIX.1-2008, the hash returned by POSIX::localeconv() includes the international currency fields added by that version of the POSIX standard. These are int_n_cs_precedes, int_n_sep_by_space, int_n_sign_posn, int_p_cs_precedes, int_p_sep_by_space, and int_p_sign_posn.
On platforms that implement neither the C99 standard nor the POSIX 2001 standard, determining if the current locale is UTF-8 or not depends on heuristics. These are improved in this release.
Variables and subroutines can now be aliased by assigning to a reference:
\$c = \$d; \&x = \&y;
Aliasing can also be accomplished by using a backslash before a foreach iterator variable; this is perhaps the most useful idiom this feature provides:
foreach \%hash (@array_of_hash_refs) { ... }
This feature is experimental and must be enabled via use feature 'refaliasing'experimental::refaliasing warnings category is disabled.
See "Assigning to References" in perlref
prototype with no arguments
prototype() with no arguments now infers $_. [GH #14376].
:const subroutine attribute
The const attribute can be applied to an anonymous subroutine. It causes the new sub to be executed immediately whenever one is created (i.e. when the sub expression is evaluated). Its value is captured and used to create a new constant subroutine that is returned. This feature is experimental. See "Constant Functions" in perlsub.
fileno now works on directory handles
When the relevant support is available in the operating system, the fileno builtin now works on directory handles, yielding the underlying file descriptor in the same way as for filehandles. On operating systems without such support, fileno on a directory handle continues to return the undefined value, as before, but also sets $! to indicate that the operation is not supported.
Currently, this uses either a dd_fd member in the OS DIR structure, or a dirfd(3) function as specified by POSIX.1-2008.
The list form of pipe:
open my $fh, "-|", "program", @arguments;
is now implemented on Win32. It has the same limitations as system LIST on Win32, since the Win32 API doesn't accept program arguments as a list.
(...) x ... can now be used within a list that is assigned to, as long as the left-hand side is a valid lvalue. This allows (undef,undef,$foo) = that_function()((undef)x2, $foo) = that_function()
Floating point values are able to hold the special values infinity, negative infinity, and NaN (not-a-number). Now we more robustly recognize and propagate the value in computations, and on output normalize them to the strings Inf, -Inf, and NaN.
See also the POSIX enhancements.
Parsing and printing of floating point values has been improved.
As a completely new feature, hexadecimal floating point literals (like 0x1.23p-4) are now supported, and they can be output with printf "%a"
Before, when trying to pack infinity or not-a-number into a (signed) character, Perl would warn, and assumed you tried to pack 0xFF; if you gave it as an argument to chr, U+FFFD was returned.
But now, all such actions (pack, chr, and print '%c') result in a fatal error.
Perl now supports (via a C level API) retrieving the C level backtrace (similar to what symbolic debuggers like gdb do).
The backtrace returns the stack trace of the C call frames, with the symbol names (function names), the object names (like "perl"), and if it can, also the source code locations (file:line).
The supported platforms are Linux and OS X (some *BSD might work at least partly, but they have not yet been tested).
The feature needs to be enabled with Configure -Dusecbacktrace.
See "C backtrace" in perlhacktips for more information.
-fstack-protector-strong if available
Perl has been compiled with the anti-stack-smashing option -fstack-protector since 5.10.1. Now Perl uses the newer variant called -fstack-protector-strong, if available.
Critical bugfix: outside packages could be replaced. Safe has been patched to 2.38 to address this.
-D_FORTIFY_SOURCE=2 if available
The 'code hardening' option called _FORTIFY_SOURCE, available in gcc 4.*, is now always used for compiling Perl, if available.
Note that this isn't necessarily a huge step since in many platforms the step had already been taken several years ago: many Linux distributions (like Fedora) have been using this option for Perl, and OS X has enforced the same for many years.
The experimental sub signatures feature, as introduced in 5.20, parsed signatures after attributes. In this release, following feedback from users of the experimental feature, the positioning has been moved such that signatures occur after the subroutine name (if any) and before the attribute list (if any).
& and \& prototypes accepts only subs
The & prototype character now accepts only anonymous subs (sub {...}), things beginning with \&, or an explicit undef. Formerly it erroneously also allowed references to arrays, hashes, and lists. [GH #2776]. [GH #14186]. [GH #14353].
In addition, the \& prototype was allowing subroutine calls, whereas now it only allows subroutines: &foo is still permitted as an argument, while &foo() and foo() no longer are. [GH #10633].
use encoding is now lexicalThe encoding pragma's effect is now limited to lexical scope. This pragma is deprecated, but in the meantime, it could adversely affect unrelated modules that are included in the same program; this change fixes that.
List slices now return an empty list only if the original list was empty (or if there are no indices). Formerly, a list slice would return an empty list if all indices fell outside the original list; now it returns a list of undef values in that case. [GH #12335].
\N{} with a sequence of multiple spaces is now a fatal error
E.g. \N{TOO MANY SPACES}\N{TRAILING SPACE }
use UNIVERSAL '...'
Importing functions from UNIVERSAL has been deprecated since v5.12, and is now a fatal error. use UNIVERSAL
\cX, X must now be a printable ASCII characterIn prior releases, failure to do this raised a deprecation warning.
(? and (* in regular expressions is now a fatal compilation error.These had been deprecated since v5.18.
qr/foo/x now ignores all Unicode pattern white space
The /x regular expression modifier allows the pattern to contain white space and comments (both of which are ignored) for improved readability. Until now, not all the white space characters that Unicode designates for this purpose were handled. The additional ones now recognized are:
U+0085 NEXT LINE U+200E LEFT-TO-RIGHT MARK U+200F RIGHT-TO-LEFT MARK U+2028 LINE SEPARATOR U+2029 PARAGRAPH SEPARATOR
The use of these characters with /x outside bracketed character classes and when not preceded by a backslash has raised a deprecation warning since v5.18. Now they will be ignored.
(?[ ])\n
(?[ ])/x is always enabled. But there was a difference: comment lines (following a # character) were terminated by anything matching \R which includes all vertical whitespace, such as form feeds. For consistency, this is now changed to match what terminates comment lines outside (?[ ])\n (even if escaped), which is the same as what terminates a heredoc string and formats.
(?[...]) operators now follow standard Perl precedenceThis experimental feature allows set operations in regular expression patterns. Prior to this, the intersection operator had the same precedence as the other binary operators. Now it has higher precedence. This could lead to different outcomes than existing code expects (though the documentation has always noted that this change might happen, recommending fully parenthesizing the expressions). See "Extended Bracketed Character Classes" in perlrecharclass.
% and @ on hash and array names is no longer permitted
Really old Perl let you omit the @ on array names and the % on hash names in some spots. This has issued a deprecation warning since Perl 5.000, and is no longer permitted.
"$!" text is now in English outside the scope of use locale
Previously, the text, unlike almost everything else, always came out based on the current underlying locale of the program. (Also affected on some systems is "$^E".) For programs that are unprepared to handle locale differences, this can cause garbage text to be displayed. It's better to display text that is translatable via some tool than garbage text which is much harder to figure out.
"$!" text will be returned in UTF-8 when appropriate
The stringification of $! and $^E will have the UTF-8 flag set when the text is actually non-ASCII UTF-8. This will enable programs that are set up to be locale-aware to properly output messages in the user's native language. Code that needs to continue the 5.20 and earlier behavior can do the stringification within the scopes of both use bytesuse locale ":messages"$! and $^E stringification. The bytes pragma causes the UTF-8 flag to not be set, just as in previous Perl releases. This resolves [GH #12035].
?PATTERN? without explicit operator has been removed
The m?PATTERN? construct, which allows matching a regex only once, previously had an alternative form that was written directly with a question mark delimiter, omitting the explicit m operator. This usage has produced a deprecation warning since 5.14.0. It is now a syntax error, so that the question mark can be available for use in new operators.
defined(@array) and defined(%hash) are now fatal errorsThese have been deprecated since v5.6.1 and have raised deprecation warnings since v5.16.
For example, %foo->{"bar"} now causes a fatal compilation error. These have been deprecated since before v5.8, and have raised deprecation warnings since then.
* prototype
The * character in a subroutine's prototype used to allow barewords to take precedence over most, but not all, subroutine names. It was never consistent and exhibited buggy behavior.
Now it has been changed, so subroutines always take precedence over barewords, which brings it into conformity with similarly prototyped built-in functions:
sub splat(*) { ... }
sub foo { ... }
splat(foo); # now always splat(foo())
splat(bar); # still splat('bar') as before
close(foo); # close(foo())
close(bar); # close('bar')
${^ENCODING} to anything but undefThis variable allows Perl scripts to be written in an encoding other than ASCII or UTF-8. However, it affects all modules globally, leading to wrong answers and segmentation faults. New scripts should be written in UTF-8; old scripts should be converted to UTF-8, which is easily done with the piconv utility.
The syntax for single-character variable names is more lenient than for longer variable names, allowing the one-character name to be a punctuation character or even invisible (a non-graphic). Perl v5.20 deprecated the ASCII-range controls as such a name. Now, all non-graphic characters that formerly were allowed are deprecated. The practical effect of this occurs only when not under use utf8
sub () { $var } with observable side-effects
In many cases Perl makes sub () { $var }$var at the time the sub expression is evaluated. This can break the closure behavior in those cases where $var is subsequently modified, since the subroutine won't return the changed value. (Note that this all only applies to anonymous subroutines with an empty prototype (sub ()
This usage is now deprecated in those cases where the variable could be modified elsewhere. Perl detects those cases and emits a deprecation warning. Such code will likely change in the future and stop producing a constant.
If your variable is only modified in the place where it is declared, then Perl will continue to make the sub inlinable with no warnings.
sub make_constant {
my $var = shift;
return sub () { $var }; # fine
}
sub make_constant_deprecated {
my $var;
$var = shift;
return sub () { $var }; # deprecated
}
sub make_constant_deprecated2 {
my $var = shift;
log_that_value($var); # could modify $var
return sub () { $var }; # deprecated
}
In the second example above, detecting that $var is assigned to only once is too hard to detect. That it happens in a spot other than the my declaration is enough for Perl to find it suspicious.
This deprecation warning happens only for a simple variable for the body of the sub. (A BEGIN block or use statement inside the sub is ignored, because it does not become part of the sub's body.) For more complex cases, such as sub () { do_something() if 0; $var }
/x regexp modifiersIt is now deprecated to say something like any of the following:
qr/foo/xx; /(?xax:foo)/; use re qw(/amxx);
That is, now x should only occur once in any string of contiguous regular expression pattern modifiers. We do not believe there are any occurrences of this in all of CPAN. This is in preparation for a future Perl release having /xx permit white-space for readability in bracketed character classes (those enclosed in square brackets: [...]).
\N{...} is now deprecatedThis non-graphic character is essentially indistinguishable from a regular space, and so should not be allowed. See "CUSTOM ALIASES" in charnames.
"{" should now be escaped in a pattern
If you want a literal left curly bracket (also called a left brace) in a regular expression pattern, you should now escape it by either preceding it with a backslash ("\{") or enclosing it within square brackets "[{]", or by using \Q; otherwise a deprecation warning will be raised. This was first announced as forthcoming in the v5.16 release; it will allow future extensions to the language to happen.
The documentation for fatal warnings notes that use warnings FATAL => 'all' is discouraged, and provides stronger language about the risks of fatal warnings in general.
SUPER::new are parsed at compile time, to save having to parse them at run time.(...)x1, ("constant")x0 and ($scalar)x0 are now optimised in list context. If the right-hand argument is a constant 1, the repetition operator disappears. If the right-hand argument is a constant 0, the whole expression is optimised to the empty list, so long as the left-hand argument is a simple scalar or constant. (That is, (foo())x0 is not subject to this optimisation.)substr assignment is now optimised into 4-argument substr at the end of a subroutine (or as the argument to return). Previously, this optimisation only happened in void context."\L...", "\Q...", etc., the extra "stringify" op is now optimised away, making these just as fast as lcfirst, quotemeta, etc.FETCH on tied arguments on the right-hand side, whereas it used to sometimes.length is applied to a non-magical, non-tied string, and either use bytes is in scope or the string doesn't use UTF-8 internally.@array = split, the assignment can be optimized away, so that split writes directly to the array. This optimisation was happening only for package arrays other than @_, and only sometimes. Now this optimisation happens almost all the time.join is now subject to constant folding. So for example join "-", "a", "b""a-b". Moreover, join with a scalar or constant for the separator and a single-item list to join is simplified to a stringification, and the separator doesn't even get evaluated.qq(@array) is implemented using two ops: a stringify op and a join op. If the qq contains nothing but a single array, the stringification is optimized away.our $varour($s,@a,%h)our $foo;state variables.-T and -B filetests will return sooner when an empty file is detected. [GH #13686]undef are now eligible for inlining. [GH #14077]utf8::native_to_unicode() and utf8::unicode_to_native() (see utf8) are now optimized out on ASCII platforms. There is now not even a minimal performance hit in writing code portable between ASCII and EBCDIC platforms.Many of the libraries distributed with perl have been upgraded since v5.20.0. For a complete list of changes, run:
corelist --diff 5.20.0 5.22.0
You can substitute your favorite version in place of 5.20.0, too.
Some notable changes include:
Tests can now be run in parallel.
The usage of memEQs in the XS has been corrected. [GH #14072]
Avoid reading beyond the end of a buffer. [perl #122629]
It provides a new B::safename function, based on the existing B::GV->SAFENAME, that converts \cOPEN to ^OPEN.
Nulled COPs are now of class B::COP, rather than B::OP.
B::REGEXP objects now provide a qr_anoncv method for accessing the implicit CV associated with qr// things containing code blocks, and a compflags method that returns the pertinent flags originating from the qr//blahblah op.
B::PMOP now provides a pmregexp method returning a B::REGEXP object. Two new classes, B::PADNAME and B::PADNAMELIST, have been introduced.
A bug where, after an ithread creation or pseudofork, special/immortal SVs in the child ithread/pseudoprocess did not have the correct class of B::SPECIAL, has been fixed. The id and outid PADLIST methods have been added.
Null ops that are part of the execution chain are now given sequence numbers.
Private flags for nulled ops are now dumped with mnemonics as they would be for the non-nulled counterparts.
It now deparses +sub : attr { ... } correctly at the start of a statement. Without the initial +, sub would be a statement label.
BEGIN blocks are now emitted in the right place most of the time, but the change unfortunately introduced a regression, in that BEGIN blocks occurring just before the end of the enclosing block may appear below it instead.
B::Deparse no longer puts erroneous local here and there, such as for LIST = tr/a//d. [perl #119815]
Adjacent use statements are no longer accidentally nested if one contains a do block. [perl #115066]
Parenthesised arrays in lists passed to \ are now correctly deparsed with parentheses (e.g., \(@a, (@b), @c) now retains the parentheses around @b), thus preserving the flattening behavior of referenced parenthesised arrays. Formerly, it only worked for one array: \(@a).
local our is now deparsed correctly, with the our included.
for($foo; !$bar; $baz) {...} was deparsed without the ! (or not). This has been fixed.
Core keywords that conflict with lexical subroutines are now deparsed with the CORE:: prefix.
foreach state $x (...) {...} now deparses correctly with state and not my.
our @array = split(...) now deparses correctly with our in those cases where the assignment is optimized away.
It now deparses our(LIST) and typed lexical (my Dog $spot) correctly.
Deparse $#_ as that instead of as $#{_}. [GH #14545]
BEGIN blocks at the end of the enclosing scope are now deparsed in the right place. [perl #77452]
BEGIN blocks were sometimes deparsed as __ANON__, but are now always called BEGIN.
Lexical subroutines are now fully deparsed. [perl #116553]
Anything =~ y///r with /r no longer omits the left-hand operand.
The op trees that make up regexp code blocks are now deparsed for real. Formerly, the original string that made up the regular expression was used. That caused problems with qr/(?{<<heredoc})/ and multiline code blocks, which were deparsed incorrectly. [perl #123217] [perl #115256]
$; at the end of a statement no longer loses its semicolon. [perl #123357]
Some cases of subroutine declarations stored in the stash in shorthand form were being omitted.
Non-ASCII characters are now consistently escaped in strings, instead of some of the time. (There are still outstanding problems with regular expressions and identifiers that have not been fixed.)
When prototype sub calls are deparsed with & (e.g., under the -P option), scalar is now added where appropriate, to force the scalar context implied by the prototype.
require(foo()), do(foo()), goto(foo()) and similar constructs with loop controls are now deparsed correctly. The outer parentheses are not optional.
Whitespace is no longer escaped in regular expressions, because it was getting erroneously escaped within (?x:...) sections.
sub foo { foo() } is now deparsed with those mandatory parentheses.
/@array/ is now deparsed as a regular expression, and not just @array.
/@{-}/, /@{+}/ and $#{1} are now deparsed with the braces, which are mandatory in these cases.
In deparsing feature bundles, B::Deparse was emitting no feature; first instead of no feature ':all';. This has been fixed.
chdir FH is now deparsed without quotation marks.
\my @a is now deparsed without parentheses. (Parenthese would flatten the array.)
system and exec followed by a block are now deparsed correctly. Formerly there was an erroneous do before the block.
use constant QR => qr/.../flags followed by "" =~ QR is no longer without the flags.
Deparsing BEGIN { undef &foo } with the -w switch enabled started to emit 'uninitialized' warnings in Perl 5.14. This has been fixed.
Deparsing calls to subs with a (;+) prototype resulted in an infinite loop. The (;$) (_) and (;_) prototypes were given the wrong precedence, causing foo($a<$b) to be deparsed without the parentheses.
Deparse now provides a defined state sub in inner subs.
B::Op_private provides detailed information about the flags used in the op_private field of perl opcodes.
Document in CAVEATS that using strings as numbers won't always invoke the big number overloading, and how to invoke it. [rt.perl.org #123064]
Carp::Heavy now ignores version mismatches with Carp if Carp is newer than 1.12, since Carp::Heavy's guts were merged into Carp at that point. [GH #13708]
Carp now handles non-ASCII platforms better.
Off-by-one error fix for Perl < 5.14.
It now accepts fully-qualified constant names, allowing constants to be defined in packages other than the caller.
Add support for Cwd::getdcwd() and introduce workaround for a misbehavior seen on Strawberry Perl 5.20.1.
Fix chdir() after building dependencies bug.
Introduce experimental support for plugins/hooks.
Integrate the App::Cpan sources.
Do not check recursion on optional dependencies.
Sanity check META.yml to contain a hash. [cpan #95271]
Works around limitations in version::vpp detecting v-string magic and adds support for forthcoming ExtUtils::MakeMaker bootstrap version.pm for Perls older than 5.10.0.
Fixes CVE-2014-4330 by adding a configuration variable/option to limit recursion when dumping deep data structures.
Changes to resolve Coverity issues. XS dumps incorrectly stored the name of code references stored in a GLOB. [GH #13911]
Remove dl_nonlazy global if unused in Dynaloader. [perl #122926]
piconv now has better error handling when the encoding name is nonexistent, and a build breakage when upgrading Encode in perl-5.8.2 and earlier has been fixed.
Building in C++ mode on Windows now works.
Add -P to the preprocessor command-line on GCC 5. GCC added extra line directives, breaking parsing of error code definitions. [rt.perl.org #123784]
Hardcodes features for Perls older than 5.15.7.
Fixes a regression on Android. [GH #14064]
Fixes a bug with maniread()'s handling of quoted filenames and improves manifind() to follow symlinks. [GH #14003]
Only declare file unused if we actually define it. Improve generated RETVAL code generation to avoid repeated references to ST(0). [perl #123278] Broaden and document the /OBJ$/ to /REF$/ typemap optimization for the DESTROY method. [perl #123418]
Add support for the Linux pipe buffer size fcntl() commands.
find() and finddepth() will now warn if passed inappropriate or misspelled options.
Avoid SvIV() expanding to call get_sv() three times in a few places. [perl #123606]
keep_alive is now fork-safe and thread-safe.
The XS implementation has been fixed for the sake of older Perls.
Document the limitations of the connected() method. [perl #123096]
A better fix for subclassing connect(). [cpan #95983] [cpan #97050]
Implements Timeout for connect(). [cpan #92075]
Support for IPv6 and SSL to Net::FTP, Net::NNTP, Net::POP3 and Net::SMTP. Improvements in Net::SMTP authentication.
Fixed a bug in the scripts used to extract data from spreadsheets that prevented the SHP currency code from being found. [cpan #94229]
New codes have been added.
Synchronize POD changes from the CPAN release. Math::BigFloat->blog(x) would sometimes return blog(2*x) when the accuracy was greater than 70 digits. The result of Math::BigFloat->bdiv() in list context now satisfies x = quotient * divisor + remainder.
Correct handling of subclasses. [cpan #96254] [cpan #96329]
Support installations on older perls with an ExtUtils::MakeMaker earlier than 6.63_03
A redundant ref $sub check has been removed.
A warning from the gcc compiler is now avoided when building the XS.
Don't turn leading // into / on Cygwin. [perl #122635]
The debugger would cause an assertion failure. [GH #14605]
fork() in the debugger under tmux will now create a new window for the forked process. [GH #13602]
The debugger now saves the current working directory on startup and restores it when you restart your program with R or rerun. [GH #13691]
Reading from a position well past the end of the scalar now correctly returns end of file. [perl #123443]
Seeking to a negative position still fails, but no longer leaves the file position set to a negation location.
eof() on a PerlIO::scalar handle now properly returns true when the file position is past the 2GB mark on 32-bit systems.
Attempting to write at file positions impossible for the platform now fail early rather than wrapping at 4GB.
Filehandles opened for reading or writing now have :encoding(UTF-8) set. [cpan #98019]
The C99 math functions and constants (for example acosh, isinf, isnan, round, trunc; M_E, M_SQRT2, M_PI) have been added.
POSIX::tmpnam() now produces a deprecation warning. [perl #122005]
reval was not propagating void context properly.
A new module, Sub::Util, has been added, containing functions related to CODE refs, including subname (inspired by Sub::Identity) and set_subname (copied and renamed from Sub::Name). The use of GetMagic in List::Util::reduce() has also been fixed. [cpan #63211]
Simplified the build process. [perl #123413]
When pretty printing negative Time::Seconds, the "minus" is no longer lost.
Version 0.67's improved discontiguous contractions is invalidated by default and is supported as a parameter long_contraction.
The XSUB implementation has been removed in favor of pure Perl.
A new function property_values() has been added to return a given property's possible values.
A new function charprop() has been added to return the value of a given property for a given code point.
A new function charprops_all() has been added to return the values of all Unicode properties for a given code point.
A bug has been fixed so that propaliases() returns the correct short and long names for the Perl extensions where it was incorrect.
A bug has been fixed so that prop_value_aliases() returns undef instead of a wrong result for properties that are Perl extensions.
This module now works on EBCDIC platforms.
A mismatch between the documentation and the code in utf8::downgrade() was fixed in favor of the documentation. The optional second argument is now correctly treated as a perl boolean (true/false semantics) and not as an integer.
Numerous changes. See the Changes file in the CPAN distribution for details.
GetOSName() now supports Windows 8.1, and building in C++ mode now works.
Building in C++ mode now works.
Allow XSLoader to load modules from a different namespace. [perl #122455]
The following modules (and associated modules) have been removed from the core perl distribution:
This document, by Tom Christiansen, provides examples of handling Unicode in Perl.
SvSetSV doesn't do set magic.sv_usepvn_flags - fix documentation to mention the use of Newx instead of malloc.NUL may be embedded or is required to terminate a string.study() is currently a no-op.delete or exists on array values is now described as "strongly discouraged" rather than "deprecated".our.-l now notes that it will return false if symlinks aren't supported by the file system. [GH #13695]exec LIST and system LIST may fall back to the shell on Win32. Only the indirect-object syntax exec PROGRAM LIST and system PROGRAM LIST will reliably avoid using the shell.This has also been noted in perlport.
tmpfile, atoi, strtol, and strtoul are now recommended.test.valgrind make target. [GH #13658]/x modifier has been clarified to note that comments cannot be continued onto the next line by escaping them; and there is now a list of all the characters that are considered whitespace by this modifier./n modifier is described.\b{sb}, \b{wb}, \b{gcb}, and \b{g}.[A-Z], [a-z], [0-9] and any subranges thereof in regular expression bracketed character classes are guaranteed to match exactly what a naive English speaker would expect them to match, even on platforms (such as EBCDIC) where perl has to do extra work to accomplish this.qr/[\N{named sequence}]/ (see under "Selected Bug Fixes").... statement has been corrected. [GH #14054]for and while is now documented in perlsyn.$] is no longer listed as being deprecated. Instead, discussion has been added on the advantages and disadvantages of using it versus $^V. $OLD_PERL_VERSION was re-added to the documentation as the long form of $].${^ENCODING} is now marked as deprecated.%^H has been clarified to indicate it can only handle simple values.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.
(P) An internal request asked to add a scalar entry to something that wasn't a symbol table entry.
(F) You tried to use a hash as a reference, as in %foo->{"bar"} or %$ref->{"hello"}. Versions of perl <= 5.6.1 used to allow this syntax, but shouldn't have.
(F) You tried to use an array as a reference, as in @foo->[23] or @$ref->[99]. Versions of perl <= 5.6.1 used to allow this syntax, but shouldn't have.
(F) defined() is not useful on arrays because it checks for an undefined scalar value. If you want to see if the array is empty, just use if (@array) { # not empty }
(F) defined() is not usually right on hashes.
Although defined %hashundef %hashdefined %hash
If a check for non-empty is what you wanted then just put it in boolean context (see "Scalar values" in perldata):
if (%hash) {
# not empty
}
If you had defined %Foo::Bar::QUUX
(F) You passed an invalid number (like an infinity or not-a-number) to chr.
(F) You tried converting an infinity or not-a-number to an unsigned character, which makes no sense.
(F) You tried converting an infinity or not-a-number to a character, which makes no sense.
(F) You tried printing an infinity or not-a-number as a character (%c), which makes no sense. Maybe you meant '%s', or just stringifying it?
(F) You defined a character name which had multiple space characters in a row. Change them to single spaces. Usually these names are defined in the :alias import argument to use charnames, but they could be defined by a translator installed into $^H{charnames}. See "CUSTOM ALIASES" in charnames.
(F) You defined a character name which ended in a space character. Remove the trailing space(s). Usually these names are defined in the :alias import argument to use charnames, but they could be defined by a translator installed into $^H{charnames}. See "CUSTOM ALIASES" in charnames.
(F) The const attribute causes an anonymous subroutine to be run and its value captured at the time that it is cloned. Named subroutines are not cloned like this, so the attribute does not make sense on them.
(F) Something went horribly bad in hexadecimal float handling.
(F) You have configured Perl to use long doubles but the internals of the long double format are unknown, therefore the hexadecimal float output is impossible.
(F) The script run under suidperl was somehow illegal.
<-- HERE in m/%s/
(F) The two-character sequence "(?" in this context in a regular expression pattern should be an indivisible token, with nothing intervening between the "(" and the "?", but you separated them.
<-- HERE in m/%s/
(F) The two-character sequence "(*" in this context in a regular expression pattern should be an indivisible token, with nothing intervening between the "(" and the "*", but you separated them.
(F) The pattern looks like a {min,max} quantifier, but the min or max could not be parsed as a valid number: either it has leading zeroes, or it represents too big a number to cope with. The <-- HERE shows where in the regular expression the problem was discovered. See perlre.
(F) You used \b{...} or \B{...} and the ... is not known to Perl. The current valid ones are given in "\b{}, \b, \B{}, \B" in perlrebackslash.
(F) You tried to call require with no argument or with an undefined value as an argument. require expects either a package name or a file-specification as an argument. See "require" in perlfunc.
Formerly, require with no argument or undef warned about a Null filename.
(D deprecated) The /\C/ character class was deprecated in v5.20, and now emits a warning. It is intended that it will become an error in v5.24. This character class matches a single byte even if it appears within a multi-byte character, breaks encapsulation, and can corrupt UTF-8 strings.
(W regexp) (only under use re 'strict'(?[...]))
You specified a character that has the given plainer way of writing it, and which is also portable to platforms running with different character sets.
(W numeric) The indicated string was fed as an argument to the ++ operator which expects either a number or a string matching /^[a-zA-Z]*[0-9]*\z/. See "Auto-increment and Auto-decrement" in perlop for details.
(W regexp) (only under use re 'strict'(?[...]))
In a bracketed character class in a regular expression pattern, you had a range which has exactly one end of it specified using \N{}, and the other end is specified using a non-portable mechanism. Perl treats the range as a Unicode range, that is, all the characters in it are considered to be the Unicode characters, and which may be different code points on some platforms Perl runs on. For example, [\N{U+06}-\x08] is treated as if you had instead said [\N{U+06}-\N{U+08}], that is it matches the characters whose code points in Unicode are 6, 7, and 8. But that \x08 might indicate that you meant something different, so the warning gets raised.
(W locale) You are 1) running under "use locale"; 2) the current locale is not a UTF-8 one; 3) you tried to do the designated case-change operation on the specified Unicode character; and 4) the result of this operation would mix Unicode and locale rules, which likely conflict.
The warnings category locale is new.
(S experimental::const_attr) The const attribute is experimental. If you want to use the feature, disable the warning with no warnings 'experimental::const_attr', but know that in doing so you are taking the risk that your code may break in a future Perl version.
(W overflow) You called gmtime with a number that it could not handle: too large, too small, or NaN. The returned value is undef.
(W overflow) The hexadecimal floating point has larger exponent than the floating point supports.
(W overflow) The hexadecimal floating point has smaller exponent than the floating point supports.
(W overflow) The hexadecimal floating point literal had more bits in the mantissa (the part between the 0x and the exponent, also known as the fraction or the significand) than the floating point supports.
(W overflow) The hexadecimal floating point had internally more digits than could be output. This can be caused by unsupported long double formats, or by 64-bit integers not being available (needed to retrieve the digits under some configurations).
(W locale) You are using the named locale, which is a non-UTF-8 one, and which perl has determined is not fully compatible with what it can handle. The second %s gives a reason.
The warnings category locale is new.
(W overflow) You called localtime with a number that it could not handle: too large, too small, or NaN. The returned value is undef.
(W numeric) You tried to execute the x repetition operator fewer than 0 times, which doesn't make sense.
(D deprecated) You defined a character name which contained a no-break space character. Change it to a regular space. Usually these names are defined in the :alias import argument to use charnames, but they could be defined by a translator installed into $^H{charnames}. See "CUSTOM ALIASES" in charnames.
(W numeric) You tried to execute the x repetition operator Inf (or -Inf) or NaN times, which doesn't make sense.
(S experimental::win32_perlio) The :win32 PerlIO layer is experimental. If you want to take the risk of using this layer, simply disable this warning:
no warnings "experimental::win32_perlio";
(W regexp) (only under use re 'strict'(?[...]))
Stricter rules help to find typos and other errors. Perhaps you didn't even intend a range here, if the "-" was meant to be some other character, or should have been escaped (like "\-"). If you did intend a range, the one that was used is not portable between ASCII and EBCDIC platforms, and doesn't have an obvious meaning to a casual reader.
[3-7] # OK; Obvious and portable [d-g] # OK; Obvious and portable [A-Y] # OK; Obvious and portable [A-z] # WRONG; Not portable; not clear what is meant [a-Z] # WRONG; Not portable; not clear what is meant [%-.] # WRONG; Not portable; not clear what is meant [\x41-Z] # WRONG; Not portable; not obvious to non-geek
(You can force portability by specifying a Unicode range, which means that the endpoints are specified by \N{...}, but the meaning may still not be obvious.) The stricter rules require that ranges that start or stop with an ASCII character that is not a control have all their endpoints be a literal character, and not some escape sequence (like "\x41"), and the ranges must be all digits, or all uppercase letters, or all lowercase letters.
(W regexp) (only under use re 'strict'(?[...]))
Stricter rules help to find typos and other errors. You included a range, and at least one of the end points is a decimal digit. Under the stricter rules, when this happens, both end points should be digits in the same group of 10 consecutive digits.
(W redundant) You called a function with more arguments than were needed, as indicated by information within other arguments you supplied (e.g. a printf format). Currently only emitted when a printf-type format required fewer arguments than were supplied, but might be used in the future for e.g. "pack" in perlfunc.
The warnings category redundant is new. See also [GH #13534].
This is not a new diagnostic, but in earlier releases was accidentally not displayed if the transliteration contained wide characters. This is now fixed, so that you may see this diagnostic in places where you previously didn't (but should have).
(W locale) You are matching a regular expression using locale rules, and a Unicode boundary is being matched, but the locale is not a Unicode one. This doesn't make sense. Perl will continue, assuming a Unicode (UTF-8) locale, but the results could well be wrong except if the locale happens to be ISO-8859-1 (Latin1) where this message is spurious and can be ignored.
The warnings category locale is new.
(W regexp) You used a Unicode boundary (\b{...} or \B{...}) in a portion of a regular expression where the character set modifiers /a or /aa are in effect. These two modifiers indicate an ASCII interpretation, and this doesn't make sense for a Unicode definition. The generated regular expression will compile so that the boundary uses all of Unicode. No other portion of the regular expression is affected.
(S experimental::bitwise) This warning is emitted if you use bitwise operators (& | ^ ~ &. |. ^. ~.) with the "bitwise" feature enabled. 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::bitwise"; use feature "bitwise"; $x |.= $y;
(D deprecated, regexp) You used a literal "{" character in a regular expression pattern. You should change to use "\{" instead, because a future version of Perl (tentatively v5.26) will consider this to be a syntax error. If the pattern delimiters are also braces, any matching right brace ("}") should also be escaped to avoid confusing the parser, for example,
qr{abc\{def\}ghi}
(D deprecated) Using literal non-graphic (including control) characters in the source to refer to the ^FOO variables, like $^X and ${^GLOBAL_PHASE} is now deprecated.
(W misc) The const attribute has no effect except on anonymous closure prototypes. You applied it to a subroutine via attributes.pm. This is only useful inside an attribute handler for an anonymous subroutine.
This is not a new diagnostic, but in earlier releases was accidentally not displayed if the transliteration contained wide characters. This is now fixed, so that you may see this diagnostic in places where you previously didn't (but should have).
(S experimental::re_strict) The things that are different when a regular expression pattern is compiled under 'strict' are subject to change in future Perl releases in incompatible ways; there are also proposals to change how to enable strict checking instead of using this subpragma. This means that a pattern that compiles today may not in a future Perl release. This warning is to alert you to that risk.
Warning: unable to close filehandle %s properly: %s
(S io) Previously, perl silently ignored any errors when doing an implicit close of a filehandle, i.e. where the reference count of the filehandle reached zero and the user's code hadn't already called close(); e.g.
{
open my $fh, '>', $file or die "open: '$file': $!\n";
print $fh, $data or die;
} # implicit close here
In a situation such as disk full, due to buffering, the error may only be detected during the final close, so not checking the result of the close is dangerous.
So perl now warns in such situations.
(W locale) While in a single-byte locale (i.e., a non-UTF-8 one), a multi-byte character was encountered. Perl considers this character to be the specified Unicode code point. Combining non-UTF-8 locales and Unicode is dangerous. Almost certainly some characters will have two different representations. For example, in the ISO 8859-7 (Greek) locale, the code point 0xC3 represents a Capital Gamma. But so also does 0x393. This will make string comparisons unreliable.
You likely need to figure out how this multi-byte character got mixed up with your single-byte locale (or perhaps you thought you had a UTF-8 locale, but Perl disagrees).
The warnings category locale is new.
This warning has been changed to <> at require-statement should be quotes to make the issue more identifiable.
The perldiag entry for this warning has added this clarifying note:
Note that for the Inf and NaN (infinity and not-a-number) the definition of "numeric" is somewhat unusual: the strings themselves (like "Inf") are considered numeric, and anything following them is considered non-numeric.
This message has had '(did you forget to declare "my %s"?)' appended to it, to make it more helpful to new Perl programmers. [GH #13732]
<-- HERE in m/%s/
This message has had character class changed to inverted character class or as a range end-point is to reflect improvements in qr/[\N{named sequence}]/ (see under "Selected Bug Fixes").
This message has had ': %f' appended to it, to show what the offending floating point number is.
This warning is now only produced when the newline is at the end of the filename.
%s will not stay shared" has been changed to say "Subroutine" when it is actually a lexical sub that will not stay shared.The perldiag entry for this warning has had information about Unicode behavior added.
There is actually no ambiguity here, and this impedes the use of negated constants; e.g., -Inf.
Compile-time checking of constant dereferencing (e.g., my_constant->()) has been removed, since it was not taking overloading into account. [GH #9891] [GH #14044]
This removes find2perl, s2p and a2p. They have all been released to CPAN as separate distributions (App::find2perl, App::s2p, App::a2p).
$Config{cppsymbols}. [GH #14491].lrintl(), lroundl(), llrintl(), and llroundl().-Dmksymlinks should now be faster. [GH #13890].pthreads and cl libraries will be linked by default if present. This allows XS modules that require threading to work on non-threaded perls. Note that you must still pass -Dusethreads if you want a threaded perl.make test.valgrind now supports parallel testing.For example:
TEST_JOBS=9 make test.valgrind
See "valgrind" in perlhacktips for more information.
This was an unmaintained attempt at preserving the Perl parse tree more faithfully so that automatic conversion of Perl 5 to Perl 6 would have been easier.
This build-time configuration option had been unmaintained for years, and had probably seriously diverged on both Perl 5 and Perl 6 sides.
-DPERL_OP_PARENT is available. For details, see the discussion below at "Internal Changes".$1..$n capture vars that Perl_save_re_context() is hard-coded to localize, because that function has no efficient way of determining at runtime what vars to localize.watchdog().test.pl now allows plan skip_all => $reason, to make it more compatible with Test::More.
Some make test failures remain: [GH #14557] and [GH #14727] for IRIX; [GH #14629], [cpan #99605], and [cpan #104836] for Tru64.
Core perl now works on this EBCDIC platform. Earlier perls also worked, but, even though support wasn't officially withdrawn, recent perls would not compile and run well. Perl 5.20 would work, but had many bugs which have now been fixed. Many CPAN modules that ship with Perl still fail tests, including Pod::Simple. However the version of Pod::Simple currently on CPAN should work; it was fixed too late to include in Perl 5.22. Work is under way to fix many of the still-broken CPAN modules, which likely will be installed on CPAN when completed, so that you may not have to wait until Perl 5.24 to get a working version.
NeXTSTEP was a proprietary operating system bundled with NeXT's workstations in the early to mid 90s; OPENSTEP was an API specification that provided a NeXTSTEP-like environment on a non-NeXTSTEP system. Both are now long dead, so support for building Perl on them has been removed.
Special handling is required of the perl interpreter on EBCDIC platforms to get qr/[i-j]/ to match only "i" and "j", since there are 7 characters between the code points for "i" and "j". This special handling had only been invoked when both ends of the range are literals. Now it is also invoked if any of the \N{...} forms for specifying a character by name or Unicode code point is used instead of a literal. See "Character Ranges" in perlrecharclass.
The archname now distinguishes use64bitint from use64bitall.
Build support has been improved for cross-compiling in general and for Android in particular.
finite, finitel, and isfinite detection has been added to configure.com, environment handling has had some minor changes, and a fix for legacy feature checking status.-fno-strict-aliasing, allowing 64-bit builds to complete on GCC 4.8. [GH #14556]nmake minitest now works on Win32. Due to dependency issues you need to build nmake test-prep first, and a small number of the tests fail. [GH #14318]USE_CPLUSPLUS to the value "define".system LIST this does not fall back to the shell. [GH #13574]DebugSymbols and DebugFull configuration options added to Windows makefiles.@INC.%I64d is now being used instead of %lld for MinGW.:win32 layer, a crash in open was fixed. Also opening /dev/null (which works under Win32 Perl's default :unix layer) was implemented for :win32. [GH #13968]USE_LONG_DOUBLE, has been added to the Windows dmake makefile for gcc builds only. Set this to "define" if you want perl to use long doubles to give more accuracy and range for floating point numbers.
On OpenBSD, Perl will now default to using the system malloc due to the security features it provides. Perl's own malloc wrapper has been in use since v5.14 due to performance reasons, but the OpenBSD project believes the tradeoff is worth it and would prefer that users who need the speed specifically ask for it.
-Dusedtrace would fail early since make didn't follow implied dependencies to build perldtrace.h. Added an explicit dependency to depend. [GH #13334]solstudio as well as SUNWspro; and support for native setenv has been added.-DPERL_OP_PARENT. It is envisaged that this will eventually become enabled by default, so XS code which directly accesses the op_sibling field of ops should be updated to be future-proofed.
On PERL_OP_PARENT builds, the op_sibling field has been renamed op_sibparent and a new flag, op_moresib, added. On the last op in a sibling chain, op_moresib is false and op_sibparent points to the parent (if any) rather than being NULL.
To make existing code work transparently whether using PERL_OP_PARENT or not, a number of new macros and functions have been added that should be used, rather than directly manipulating op_sibling.
For the case of just reading op_sibling to determine the next sibling, two new macros have been added. A simple scan through a sibling chain like this:
for (; kid->op_sibling; kid = kid->op_sibling) { ... }
should now be written as:
for (; OpHAS_SIBLING(kid); kid = OpSIBLING(kid)) { ... }
For altering optrees, a general-purpose function op_sibling_splice() has been added, which allows for manipulation of a chain of sibling ops. By analogy with the Perl function splice(), it allows you to cut out zero or more ops from a sibling chain and replace them with zero or more new ops. It transparently handles all the updating of sibling, parent, op_last pointers etc.
If you need to manipulate ops at a lower level, then three new macros, OpMORESIB_set, OpLASTSIB_set and OpMAYBESIB_set are intended to be a low-level portable way to set op_sibling / op_sibparent while also updating op_moresib. The first sets the sibling pointer to a new sibling, the second makes the op the last sibling, and the third conditionally does the first or second action. Note that unlike op_sibling_splice() these macros won't maintain consistency in the parent at the same time (e.g. by updating op_first and op_last where appropriate).
A C-level Perl_op_parent() function and a Perl-level B::OP::parent() method have been added. The C function only exists under PERL_OP_PARENT builds (using it is build-time error on vanilla perls). B::OP::parent() exists always, but on a vanilla build it always returns NULL. Under PERL_OP_PARENT, they return the parent of the current op, if any. The variable $B::OP::does_parent allows you to determine whether B supports retrieving an op's parent.
PERL_OP_PARENT was introduced in 5.21.2, but the interface was changed considerably in 5.21.11. If you updated your code before the 5.21.11 changes, it may require further revision. The main changes after 5.21.2 were:
OP_SIBLING and OP_HAS_SIBLING macros have been renamed OpSIBLING and OpHAS_SIBLING for consistency with other op-manipulating macros.op_lastsib field has been renamed op_moresib, and its meaning inverted.OpSIBLING_set has been removed, and has been superseded by OpMORESIB_set et al.op_sibling_splice() function now accepts a null parent argument where the splicing doesn't affect the first or last ops in the sibling chainLC_NUMERIC. See "Locale-related functions and macros" in perlapi.atoi et al replacement function, grok_atou, has now been superseded by grok_atoUV. See perlclib for details.Perl_sv_get_backrefs(), has been added which allows you retrieve the weak references, if any, which point at an SV.screaminstr() function has been removed. Although marked as public API, it was undocumented and had no usage in CPAN modules. Calling it has been fatal since 5.17.0.newDEFSVOP(), block_start(), block_end() and intro_my() functions have been added to the API.convert function in op.c has been renamed op_convert_list and added to the API.sv_magic() function no longer forbids "ext" magic on read-only values. After all, perl can't know whether the custom magic will modify the SV or not. [GH #14202].
The CvPADLIST field has been reused for a different internal purpose for XSUBs. So in particular, you can no longer rely on it being NULL as a test of whether a CV is an XSUB. Use CvISXSUB() instead.
SVt_NV are now sometimes bodiless when the build configuration and platform allow it: specifically, when sizeof(NV) <= sizeof(IV). "Bodiless" means that the NV value is stored directly in the head of an SV, without requiring a separate body to be allocated. This trick has already been used for IVs since 5.9.2 (though in the case of IVs, it is always used, regardless of platform and build configuration).$DB::single, $DB::signal and $DB::trace variables now have set- and get-magic that stores their values as IVs, and those IVs are used when testing their values in pp_dbstate(). This prevents perl from recursing infinitely if an overloaded object is assigned to any of those variables. [GH #14013].Perl_tmps_grow(), which is marked as public API but is undocumented, has been removed from the public API. This change does not affect XS code that uses the EXTEND_MORTAL macro to pre-extend the mortal stack.SVs_PADMY flag. SvPADMY() now returns a true value for anything not marked PADTMP and SVs_PADMY is now defined as 0.SETsv and SETsvUN have been removed. They were no longer used in the core since commit 6f1401dc2a five years ago, and have not been found present on CPAN.SvFAKE bit (unused on HVs) got informally reserved by David Mitchell for future work on vtables.sv_catpvn_flags() function accepts SV_CATBYTES and SV_CATUTF8 flags, which specify whether the appended string is bytes or UTF-8, respectively. (These flags have in fact been present since 5.16.0, but were formerly not regarded as part of the API.)METHOP, has been introduced. It holds information used at runtime to improve the performance of class/object method calls.
OP_METHOD and OP_METHOD_NAMED have changed from being UNOP/SVOP to being METHOP.
cv_name() is a new API function that can be passed a CV or GV. It returns an SV containing the name of the subroutine, for use in diagnostics.cv_set_call_checker_flags() is a new API function that works like cv_set_call_checker(), except that it allows the caller to specify whether the call checker requires a full GV for reporting the subroutine's name, or whether it could be passed a CV instead. Whatever value is passed will be acceptable to cv_name(). cv_set_call_checker() guarantees there will be a GV, but it may have to create one on the fly, which is inefficient. [GH #12767]CvGV (which is not part of the API) is now a more complex macro, which may call a function and reify a GV. For those cases where it has been used as a boolean, CvHASGV has been added, which will return true for CVs that notionally have GVs, but without reifying the GV. CvGV also returns a GV now for lexical subs. [GH #13392]Gtk. When this happens, Perl needs to be told that the locale has changed. Use this function to do so, before returning to Perl.op_private field of OPs are now auto-generated from data in regen/op_private. The noticeable effect of this is that some of the flag output of Concise might differ slightly, and the flag output of perl -Dxop_free() to ensure that the op doesn't have any unrecognized flags set in op_private.PL_sv_objcount has been removed.LC_NUMERIC set to "C" except around operations that need it to be set to the program's underlying locale. This protects the many XS modules that cannot cope with the decimal radix character not being a dot. Prior to this release, Perl initialized this category to "C", but a call to POSIX::setlocale() would change it. Now such a call will change the underlying locale of the LC_NUMERIC category for the program, but the locale exposed to XS code will remain "C". There are new macros to manipulate the LC_NUMERIC locale, including STORE_LC_NUMERIC_SET_TO_NEEDED and STORE_LC_NUMERIC_FORCE_TO_UNDERLYING. See "Locale-related functions and macros" in perlapi.isUTF8_CHAR has been written which efficiently determines if the string given by its parameters begins with a well-formed UTF-8 encoded character.Perl_cast_ulong, Perl_cast_i32, Perl_cast_iv, Perl_cast_uv, Perl_cv_const_sv, Perl_mg_find, Perl_mg_findext, Perl_mg_magical, Perl_mini_mktime, Perl_my_dirfd, Perl_sv_backoff, Perl_utf8_hop.
Note that the prefix-less versions of those functions that are part of the public API, such as cast_i32(), remain unaffected.
PADNAME and PADNAMELIST types are now separate types, and no longer simply aliases for SV and AV. [GH #14250].PadnameUTF8 macro always returns true. Previously, this was effectively the case already, but any support for two different internal representations of pad names has now been removed.UNOP_AUX, has been added. This is a subclass of UNOP with an op_aux field added, which points to an array of unions of UV, SV* etc. It is intended for where an op needs to store more data than a simple op_sv or whatever. Currently the only op of this type is OP_MULTIDEREF (see next item).OP_MULTIDEREF, which performs one or more nested array and hash lookups where the key is a constant or simple variable. For example the expression $a[0]{$k}[$i], which previously involved ten rv2Xv, Xelem, gvsv and const ops is now performed by a single multideref op. It can also handle local, exists and delete. A non-simple index expression, such as [$i+1] is still done using aelem/helem, and single-level array lookup with a small constant index is still done using aelemfast.close now sets $!
When an I/O error occurs, the fact that there has been an error is recorded in the handle. close returns false for such a handle. Previously, the value of $! would be untouched by close, so the common convention of writing close $fh or die $!$!, too, and close restores it.
no re now can turn off everything that use re enables
Previously, running no re would turn off only a few things. Now it can turn off all the enabled things. For example, the only way to stop debugging, once enabled, was to exit the enclosing block; that is now fixed.
pack("D", $x) and pack("F", $x) now zero the padding on x86 long double builds. Under some build options on GCC 4.8 and later, they used to either overwrite the zero-initialized padding, or bypass the initialized buffer entirely. This caused op/pack.t to fail. [GH #14554]*x=<y> has been fixed. [GH #14493]split in the scope of lexical $_ has been fixed not to fail assertions. [GH #14483]my $x : attr syntax inside various list operators no longer fails assertions. [GH #14500]@ sign in quotes followed by a non-ASCII digit (which is not a valid identifier) would cause the parser to crash, instead of simply trying the @ as literal. This has been fixed. [GH #14553]*bar::=*foo::=*glob_with_hash has been crashing since Perl 5.14, but no longer does. [GH #14512]foreach in scalar context was not pushing an item on to the stack, resulting in bugs. (print 4, scalar do { foreach(@x){} } + 1undef. [GH #14569]/.*..../ matched against long strings have been slow since v5.8, and some of the form /.*..../i have been slow since v5.18. They are now all fast again. [GH #14475].$/ is now preserved when it is set to an invalid value. Previously if you set $/ to a reference to an array, for example, perl would produce a runtime error and not set PL_rs, but Perl code that checked $/ would see the array reference. [GH #14245].[:ascii:], must be inside a bracketed character class, like qr/[[:ascii:]]/. A warning is issued when something looking like a POSIX class is not inside a bracketed class. That warning wasn't getting generated when the POSIX class was negated: [:^ascii:]. This is now fixed.eval { LABEL: }/$a[/ used to read the next line of input and treat it as though it came immediately after the opening bracket. Some invalid code consequently would parse and run, but some code caused crashes, so this is now disallowed. [GH #14462].pack. [GH #14525].\x{}. Now \x{} is equivalent to \x{0} instead of faulting.stat -t is now no longer treated as stackable, just like -t stat. [GH #14499].qr{x+(y(?0))*}./i while taking into account the current POSIX locale (which usually means they have to be compiled within the scope of use locales///g now works on very long strings (where there are more than 2 billion iterations) instead of dying with 'Substitution loop'. [GH #11742]. [GH #14190].gmtime no longer crashes with not-a-number values. [GH #14365].\() (a reference to an empty list), and y/// with lexical $_ in scope, could both do a bad write past the end of the stack. They have both been fixed to extend the stack first.prototype() with no arguments used to read the previous item on the stack, so print "foo", prototype()$_ instead. [GH #14376].s/${<>{})//, would crash, and had done so since Perl 5.10. (In some cases the crash did not start happening till 5.16.) The crash has, of course, been fixed. [GH #14391].33 x ~3SvGROW(). An expression like this now properly produces a memory wrap panic. [GH #14401].formline("@...", "a"); would crash. The FF_CHECKNL case in pp_formline() didn't set the pointer used to mark the chop position, which led to the FF_MORE case crashing with a segmentation fault. This has been fixed. [GH #14388].fchmod() and futimes() now set $! when they fail due to being passed a closed file handle. [GH #14073].op_free() and scalarvoid() no longer crash due to a stack overflow when freeing a deeply recursive op tree. [GH #11866].$^N accidentally had the internal UTF-8 flag turned off if accessed from a code block within a regular expression, effectively UTF-8-encoding the value. This has been fixed. [GH #14211].semctl call no longer overwrites existing items on the stack, which means that (semctl(-1,0,0,0))[0] no longer gives an "uninitialized" warning.else{foo()} with no space before foo is now better at assigning the right line number to that statement. [GH #14070].@array = split gets optimised so that split itself writes directly to the array. This caused a bug, preventing this assignment from being used in lvalue context. So (@a=split//,"foo")=bar() was an error. (This bug probably goes back to Perl 3, when the optimisation was added.) It has now been fixed. [GH #14183]... and ... in scalar context) used to maintain a separate state for each recursion level (the number of times the enclosing sub was called recursively), contrary to the documentation. Now each closure has one internal state for each flip-flop. [GH #14110]... in scalar context) would return the same scalar each time, unless the containing subroutine was called recursively. Now it always returns a new scalar. [GH #14110].use, no, statement labels, special blocks (BEGIN) and pod are now permitted as the first thing in a map or grep block, the block after print or say (or other functions) returning a handle, and within ${...}, @{...}, etc. [GH #14088].x now propagates lvalue context to its left-hand argument when used in contexts like foreach. That allows for(($#that_array)x2) { ... }$_.(...) x ... in scalar context used to corrupt the stack if one operand was an object with "x" overloading, causing erratic behavior. [GH #13811].my $x; $x = $y + $z, the assign operator is optimised away and the add operator writes its result directly to $x. Various bugs related to this optimisation have been fixed. Certain operators on the right-hand side would sometimes fail to assign the value at all or assign the wrong value, or would call STORE twice or not at all on tied variables. The operators affected were $foo++, $foo--, and -$foo under use integer, chomp, chr and setpgrp.tied, values or each. The result would be the wrong value getting assigned.setpgrp($nonzero) (with one argument) was accidentally changed in 5.16 to mean setpgrp(0). This has been fixed.__SUB__ could return the wrong value or even corrupt memory under the debugger (the -d switch) and in subs containing eval $string.sub () { $var }my sub f () { $var }sub () : attr { $var }:method attribute, which does nothing much.eval or state declaration or closing over an outer lexical variable (or any anonymous sub under the debugger). Now any sub that gets folded to a single constant after statements have been optimised away is eligible for inlining. This applies to things like sub () { jabber() if DEBUG; 42 }.
Some subroutines with an explicit return were being made inlinable, contrary to the documentation, Now return always prevents inlining.
crypt can return a non-ASCII string. If a scalar assigned to had contained a UTF-8 string previously, then crypt would not turn off the UTF-8 flag, thus corrupting the return value. This would happen with $lexical = crypt ...crypt no longer calls FETCH twice on a tied first argument.qq[${ <<END }], /(?{ <<END })/) no longer causes a double free. It started doing so in 5.18.index() and rindex() no longer crash when used on strings over 2GB in size. [GH #13700].PERL_SYS_INIT/PERL_SYS_INIT3 on Win32 builds was fixed. This might affect embedders who repeatedly create and destroy perl engines within the same process.POSIX::localeconv() now returns the data for the program's underlying locale even when called from outside the scope of use localePOSIX::localeconv() now works properly on platforms which don't have LC_NUMERIC and/or LC_MONETARY, or for which Perl has been compiled to disregard either or both of these locale categories. In such circumstances, there are now no entries for the corresponding values in the hash returned by localeconv().POSIX::localeconv() now marks appropriately the values it returns as UTF-8 or not. Previously they were always returned as bytes, even if they were supposed to be encoded as UTF-8.use locale[[:alnum:]], [[:alpha:]], [[:blank:]], [[:digit:]], [[:graph:]], [[:lower:]], [[:print:]], [[:punct:]], [[:upper:]], [[:word:]], and [[:xdigit:]]. This was because the underlying Microsoft implementation does not follow the standard. Perl now takes special precautions to correct for this.system() and friends should now work properly on more Android builds.
Due to an oversight, the value specified through -Dtargetsh to Configure would end up being ignored by some of the build process. This caused perls cross-compiled for Android to end up with defective versions of system(), exec() and backticks: the commands would end up looking for /bin/sh instead of /system/bin/sh, and so would fail for the vast majority of devices, leaving $! as ENOENT.
qr(...\(...\)...), qr[...\[...\]...], and qr{...\{...\}...} now work. Previously it was impossible to escape these three left-characters with a backslash within a regular expression pattern where otherwise they would be considered metacharacters, and the pattern opening delimiter was the character, and the closing delimiter was its mirror character.s///e on tainted UTF-8 strings corrupted pos(). This bug, introduced in 5.20, is now fixed. [GH #13948].\B) did not always match the end of the string; in particular q{} =~ /\B/ did not match. This bug, introduced in perl 5.14, is now fixed. [GH #13917]." P" =~ /(?=.*P)P/ should match, but did not. This is now fixed. [GH #13954].use Foo in an eval could leave a spurious BEGIN subroutine definition, which would produce a "Subroutine BEGIN redefined" warning on the next use of use, or other BEGIN block. [GH #13926].method { BLOCK } ARGS syntax now correctly parses the arguments if they begin with an opening brace. [GH #9085].pos to see an incorrect value. [GH #14016].$ @ % &) followed by braces, the parser no longer tries to guess whether it is a block or a hash constructor (causing a syntax error when it guesses the latter), since it can only be a block.undef $referencesub () { 3 }) no longer deletes any subroutine named __ANON__ in the current package. Not only was *__ANON__{CODE} cleared, but there was a memory leak, too. This bug goes back to Perl 5.8.0.sub f; and sub f (); no longer wipe out constants of the same name declared by use constant. This bug was introduced in Perl 5.10.0.qr/[\N{named sequence}]/ now works properly in many instances.
Some names known to \N{...} refer to a sequence of multiple characters, instead of the usual single character. Bracketed character classes generally only match single characters, but now special handling has been added so that they can match named sequences, but not if the class is inverted or the sequence is specified as the beginning or end of a range. In these cases, the only behavior change from before is a slight rewording of the fatal error message given when this class is part of a ?[...]) construct. When the [...] stands alone, the same non-fatal warning as before is raised, and only the first character in the sequence is used, again just as before.
open $$fh, ..."main::_GEN_0", was not giving the handle the right reference count, so a double free could happen.our sub with the same name existed, and look up the method in the package of the our sub, instead of the package of the invocant.\U= within a double-quoted string. It used to produce a syntax error, but now compiles it correctly. [GH #10882]-B and -T file test operators to treat UTF-8 encoded files as text. (perlfunc has been updated to say this.) Previously, it was possible for some files to be considered UTF-8 that actually weren't valid UTF-8. This is now fixed. The operators now work on EBCDIC platforms as well.use warnings or no warnings) were not in effect and $^W were false at compile time and true at run time.$SomePackage::{__ANON__} and then undefining an anonymous subroutine could corrupt things internally, resulting in Devel::Peek crashing or B.pm giving nonsensical data. This has been fixed.(caller $n)[3]"(unknown)".sort subname LIST now supports using a lexical sub as the comparison routine.*x = *ysplit to treat split /^/split /^/msplit /\A/split /^/msplit /^x/split /^x/mmy Class $varuse utf8 if Class were a constant whose value contained Latin-1 characters.Internals::SvREADONLY no longer has any effect on values that were read-only to begin with. Previously, unlocking such values could result in crashes, hangs or other erratic behavior.(?(...)...) constructs in regular expressions would either crash or give erroneous error messages. /(?(1)/ is one such example.pack "w", $tied($x, $z) = (1, $y)$x and $y have been aliased by foreach./ (?{(^{})/sort with debugging enabled has been fixed. [GH #14087].*a = *b; @a = split //, $b[1]() = @array = split() =make distclean to incorrectly leave some files behind. [GH #14108].getsockopt correctly. [GH #13484]. [cpan #91183]. [cpan #85570].while(1) within a sublist, e.g.
sub foo { () = ($a, my $b, ($c, do { while(1) {} })) }
The bug was introduced in 5.20.0 [GH #14165].
local-ized in a pseudo-process that later forked, restoring the original value in the child pseudo-process caused memory corruption and a crash in the child pseudo-process (and therefore the OS process). [GH #8641].write on a format with a ^** field could produce a panic in sv_chop() if there were insufficient arguments or if the variable used to fill the field was empty. [GH #14255].\@ subroutine prototype no longer flattens parenthesized arrays (taking a reference to each element), but takes a reference to the array itself. [GH #9111].for loop could corrupt the stack, causing lists outside the block to lose elements or have elements overwritten. This could happen with map { for(...){...} } ... and with lists containing do { for(...){...} }. [GH #14269].scalar() now propagates lvalue context, so that for(scalar($#foo)) { ... }$#foo through $_.qr/@array(?{block})/ no longer dies with "Bizarre copy of ARRAY". [GH #14292].eval '$variable'sort CORE::fake where 'fake' is anything other than a keyword, started chopping off the last 6 characters and treating the result as a sort sub name. The previous behavior of treating CORE::fake as a sort sub name has been restored. [GH #14323].use utf8, a single-character Latin-1 lexical variable is disallowed. The error message for it, "Can't use global $foo...", was giving garbage instead of the variable name.readline on a nonexistent handle was causing ${^LAST_FH} to produce a reference to an undefined scalar (or fail an assertion). Now ${^LAST_FH} ends up undefined.(...) x ... in void context now applies scalar context to the left-hand argument, instead of the context the current sub was called in. [GH #14174].pack-ing a NaN on a perl compiled with Visual C 6 does not behave properly, leading to a test failure in t/op/infnan.t. [GH #14705]cmp (and hence sort) operators do not necessarily give the correct results when both operands are UTF-EBCDIC encoded strings and there is a mixture of ASCII and/or control characters, along with other characters.\N{...} in the tr/// (and y///) transliteration operators are treated differently than the equivalent ranges in regular expression patterns. They should, but don't, cause the values in the ranges to all be treated as Unicode code points, and not native ones. ("Version 8 Regular Expressions" in perlre gives details as to how it should work.)pack/unpack with "U0" format may not work properly.Brian McCauley died on May 8, 2015. He was a frequent poster to Usenet, Perl Monks, and other Perl forums, and made several CPAN contributions under the nick NOBULL, including to the Perl FAQ. He attended almost every YAPC::Europe, and indeed, helped organise YAPC::Europe 2006 and the QA Hackathon 2009. His wit and his delight in intricate systems were particularly apparent in his love of board games; many Perl mongers will have fond memories of playing Fluxx and other games with Brian. He will be missed.
Perl 5.22.0 represents approximately 12 months of development since Perl 5.20.0 and contains approximately 590,000 lines of changes across 2,400 files from 94 authors.
Excluding auto-generated files, documentation and release tools, there were approximately 370,000 lines of changes to 1,500 .pm, .t, .c and .h files.
Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.22.0:
Aaron Crane, Abhijit Menon-Sen, Abigail, Alberto Simões, Alex Solovey, Alex Vandiver, Alexandr Ciornii, Alexandre (Midnite) Jousset, Andreas König, Andreas Voegele, Andrew Fresh, Andy Dougherty, Anthony Heading, Aristotle Pagaltzis, brian d foy, Brian Fraser, Chad Granum, Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari Mannsåker, Daniel Dragan, Darin McBride, Dave Rolsky, David Golden, David Mitchell, David Wheeler, Dmitri Tikhonov, Doug Bell, E. Choroba, Ed J, Eric Herman, Father Chrysostomos, George Greer, Glenn D. Golden, Graham Knop, H.Merijn Brand, Herbert Breunung, Hugo van der Sanden, James E Keenan, James McCoy, James Raspass, Jan Dubois, Jarkko Hietaniemi, Jasmine Ngan, Jerry D. Hedden, Jim Cromie, John Goodyear, kafka, Karen Etheridge, Karl Williamson, Kent Fredric, kmx, Lajos Veres, Leon Timmermans, Lukas Mai, Mathieu Arnold, Matthew Horsfall, Max Maischein, Michael Bunk, Nicholas Clark, Niels Thykier, Niko Tyni, Norman Koch, Olivier Mengué, Peter John Acklam, Peter Martini, Petr Písař, Philippe Bruhat (BooK), Pierre Bogossian, Rafael Garcia-Suarez, Randy Stauner, Reini Urban, Ricardo Signes, Rob Hoelz, Rostislav Skudnov, Sawyer X, Shirakata Kentaro, Shlomi Fish, Sisyphus, Slaven Rezic, Smylers, Steffen Müller, Steve Hay, Sullivan Beck, syber, Tadeusz Sośnierz, Thomas Sibley, Todd Rinaldo, Tony Cook, Vincent Pit, Vladimir Marek, Yaroslav Kuzmin, Yves Orton, Ævar Arnfjörð Bjarmason.
The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.
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 https://rt.perl.org/. 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 perlbug@perl.org to be analysed by the Perl porting team.
If the bug you are reporting has security implications, which make it inappropriate to send to a publicly archived mailing list, then please send it to perl5-security-report@perl.org. This points to a closed subscription unarchived mailing list, which includes all 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.