| PERL5200DELTA(1) | Perl Programmers Reference Guide | PERL5200DELTA(1) |
perl5200delta - what is new for perl v5.20.0
This document describes differences between the 5.18.0 release and the 5.20.0 release.
If you are upgrading from an earlier release such as 5.16.0, first read perl5180delta, which describes differences between 5.16.0 and 5.18.0.
Declarative syntax to unwrap argument list into lexical variables. "sub foo ($a,$b) {...}" checks the number of arguments and puts the arguments into lexical variables. Signatures are not equivalent to the existing idiom of "sub foo { my($a,$b) = @_; ... }". Signatures are only available by enabling a non-default feature, and generate warnings about being experimental. The syntactic clash with prototypes is managed by disabling the short prototype syntax when signatures are enabled.
See "Signatures" in perlsub for details.
When declaring or defining a "sub", the prototype can now be specified inside of a "prototype" attribute instead of in parens following the name.
For example, "sub foo($$){}" could be rewritten as "sub foo : prototype($$){}".
Multiple semicolons in subroutine prototypes have long been tolerated and treated as a single semicolon. There was one case where this did not happen. A subroutine whose prototype begins with "*" or ";*" can affect whether a bareword is considered a method name or sub call. This now applies also to ";;;*".
Whitespace has long been allowed inside subroutine prototypes, so "sub( $ $ )" is equivalent to "sub($$)", but until now it was stripped when the subroutine was parsed. Hence, whitespace was not allowed in prototypes set by "Scalar::Util::set_prototype". Now it is permitted, and the parser no longer strips whitespace. This means "prototype &mysub" returns the original prototype, whitespace and all.
Previously perl would use a platform specific random number generator, varying between the libc rand(), random() or drand48().
This meant that the quality of perl's random numbers would vary from platform to platform, from the 15 bits of rand() on Windows to 48-bits on POSIX platforms such as Linux with drand48().
Perl now uses its own internal drand48() implementation on all platforms. This does not make perl's "rand" cryptographically secure. [perl #115928]
The new %hash{...} and %array[...] syntax returns a list of key/value (or index/value) pairs. See "Key/Value Hash Slices" in perldata.
When the "postderef" feature is in effect, the following syntactical equivalencies are set up:
$sref->$*; # same as ${ $sref } # interpolates
$aref->@*; # same as @{ $aref } # interpolates
$href->%*; # same as %{ $href }
$cref->&*; # same as &{ $cref }
$gref->**; # same as *{ $gref }
$aref->$#*; # same as $#{ $aref }
$gref->*{ $slot }; # same as *{ $gref }{ $slot }
$aref->@[ ... ]; # same as @$aref[ ... ] # interpolates
$href->@{ ... }; # same as @$href{ ... } # interpolates
$aref->%[ ... ]; # same as %$aref[ ... ]
$href->%{ ... }; # same as %$href{ ... }
Those marked as interpolating only interpolate if the associated "postderef_qq" feature is also enabled. This feature is experimental and will trigger "experimental::postderef"-category warnings when used, unless they are suppressed.
For more information, consult the Postfix Dereference Syntax section of perlref.
Perl now supports and is shipped with Unicode 6.3 (though Perl may be recompiled with any previous Unicode release as well). A detailed list of Unicode 6.3 changes is at <http://www.unicode.org/versions/Unicode6.3.0/>.
This is a synonym for "\p{Any}" and matches the set of Unicode-defined code points 0 - 0x10FFFF.
On 64-bit platforms, the internal array functions now use 64-bit offsets, allowing Perl arrays to hold more than 2**31 elements, if you have the memory available.
The regular expression engine now supports strings longer than 2**31 characters. [perl #112790, #116907]
The functions PerlIO_get_bufsiz, PerlIO_get_cnt, PerlIO_set_cnt and PerlIO_set_ptrcnt now have SSize_t, rather than int, return values and parameters.
Until this release, only single-byte locales, such as the ISO 8859 series were supported. Now, the increasingly common multi-byte UTF-8 locales are also supported. A UTF-8 locale is one in which the character set is Unicode and the encoding is UTF-8. The POSIX "LC_CTYPE" category operations (case changing (like "lc()", "\U"), and character classification ("\w", "\D", "qr/[[:punct:]]/")) under such a locale work just as if not under locale, but instead as if under "use feature 'unicode_strings'", except taint rules are followed. Sorting remains by code point order in this release. [perl #56820].
Previously doing this caused the program to not compile. Within its scope the program behaves as if in the "C" locale. Thus programs written for platforms that support locales can run on locale-less platforms without change. Attempts to change the locale away from the "C" locale will, of course, fail.
If there was an error with locales during Perl start-up, it immediately gave up and tried to use the "C" locale. Now it first tries using other locales given by the environment variables, as detailed in "ENVIRONMENT" in perllocale. For example, if "LC_ALL" and "LANG" are both set, and using the "LC_ALL" locale fails, Perl will now try the "LANG" locale, and only if that fails, will it fall back to "C". On Windows machines, Perl will try, ahead of using "C", the system default locale if all the locales given by environment variables fail.
This is designed for Perl core developers to aid in field debugging bugs regarding locales.
Previously -F without -a was a no-op, and -a without -n or -p was a no-op, with this change, if you supply -F then both -a and -n are implied and if you supply -a then -n is implied.
You can still use -p for its extra behaviour. [perl #116190]
The special variables $a and $b, used in "sort", are now exempt from "used once" warnings, even where "sort" is not used. This makes it easier for CPAN modules to provide functions using $a and $b for similar purposes. [perl #120462]
It was possible that free()d memory could be read during parsing in the unusual circumstance of the Perl program ending with a heredoc and the last line of the file on disk having no terminating newline character. This has now been fixed.
The "do SUBROUTINE(LIST)" form has resulted in a deprecation warning since Perl v5.0.0, and is now a syntax error.
The character after "\c" in a double-quoted string ("..." or qq(...)) or regular expression must now be a printable character and may not be "{".
A literal "{" after "\B" or "\b" is now fatal.
These were deprecated in perl v5.14.0.
This affects regular expression matching and changing the case of a string ("lc", "\U", etc.) within the scope of "use locale". The result is now tainted based on the operation, no matter what the contents of the string were, as the documentation (perlsec, "SECURITY" in perllocale) indicates it should. Previously, for the case change operation, if the string contained no characters whose case change could be affected by the locale, the result would not be tainted. For example, the result of "uc()" on an empty string or one containing only above-Latin1 code points is now tainted, and wasn't before. This leads to more consistent tainting results. Regular expression patterns taint their non-binary results (like $&, $2) if and only if the pattern contains elements whose matching depends on the current (potentially tainted) locale. Like the case changing functions, the actual contents of the string being matched now do not matter, whereas formerly it did. For example, if the pattern contains a "\w", the results will be tainted even if the match did not have to use that portion of the pattern to succeed or fail, because what a "\w" matches depends on locale. However, for example, a "." in a pattern will not enable tainting, because the dot matches any single character, and what the current locale is doesn't change in any way what matches and what doesn't.
"\p{}" and "\P{}" are defined by Unicode only on Unicode-defined code points ("U+0000" through "U+10FFFF"). Their behavior on matching these legal Unicode code points is unchanged, but there are changes for code points 0x110000 and above. Previously, Perl treated the result of matching "\p{}" and "\P{}" against these as "undef", which translates into "false". For "\P{}", this was then complemented into "true". A warning was supposed to be raised when this happened. However, various optimizations could prevent the warning, and the results were often counter-intuitive, with both a match and its seeming complement being false. Now all non-Unicode code points are treated as typical unassigned Unicode code points. This generally is more Do-What-I-Mean. A warning is raised only if the results are arguably different from a strict Unicode approach, and from what Perl used to do. Code that needs to be strictly Unicode compliant can make this warning fatal, and then Perl always raises the warning.
Details are in "Beyond Unicode code points" in perlunicode.
The Perl-defined regular expression pattern element "\p{All}", unused on CPAN, used to match just the Unicode code points; now it matches all possible code points; that is, it is equivalent to "qr/./s". Thus "\p{All}" is no longer synonymous with "\p{Any}", which continues to match just the Unicode code points, as Unicode says it should.
Depending on the data structures dumped and the settings set for Data::Dumper, the dumped output may have changed from previous versions.
If you have tests that depend on the exact output of Data::Dumper, they may fail.
To avoid this problem in your code, test against the data structure from evaluating the dumped structure, instead of the dump itself.
This is actually a bug fix, but some code has come to rely on the bug being present, so this change is listed here. The current locale that the program is running under is not supposed to be visible to Perl code except within the scope of a "use locale". However, until now under certain circumstances, the character used for a decimal point (often a comma) leaked outside the scope. If your code is affected by this change, simply add a "use locale".
In previous versions of Perl, Windows sockets error codes as returned by WSAGetLastError() were assigned to $!, and some constants such as ECONNABORTED, not in errno.h in VC++ (or the various Windows ports of gcc) were defined to corresponding WSAE* values to allow $! to be tested against the E* constants exported by Errno and POSIX.
This worked well until VC++ 2010 and later, which introduced new E* constants with values > 100 into errno.h, including some being (re)defined by perl to WSAE* values. That caused problems when linking XS code against other libraries which used the original definitions of errno.h constants.
To avoid this incompatibility, perl now maps WSAE* error codes to E* values where possible, and assigns those values to $!. The E* constants exported by Errno and POSIX are updated to match so that testing $! against them, wherever previously possible, will continue to work as expected, and all E* constants found in errno.h are now exported from those modules with their original errno.h values.
In order to avoid breakage in existing Perl code which assigns WSAE* values to $!, perl now intercepts the assignment and performs the same mapping to E* values as it uses internally when assigning to $! itself.
However, one backwards-incompatibility remains: existing Perl code which compares $! against the numeric values of the WSAE* error codes that were previously assigned to $! will now be broken in those cases where a corresponding E* value has been assigned instead. This is only an issue for those E* values < 100, which were always exported from Errno and POSIX with their original errno.h values, and therefore could not be used for WSAE* error code tests (e.g. WSAEINVAL is 10022, but the corresponding EINVAL is 22). (E* values > 100, if present, were redefined to WSAE* values anyway, so compatibility can be achieved by using the E* constants, which will work both before and after this change, albeit using different numeric values under the hood.)
These two functions, undocumented, unused in CPAN, and problematic, have been removed.
The "/\C/" regular expression character class is deprecated. From perl 5.22 onwards it will generate a warning, and from perl 5.24 onwards it will be a regular expression compiler error. If you need to examine the individual bytes that make up a UTF8-encoded character, then use "utf8::encode()" on the string (or a copy) first.
This deprecation affects things like $\cT, where \cT is a literal control (such as a "NAK" or "NEGATIVE ACKNOWLEDGE" character) in the source code. Surprisingly, it appears that originally this was intended as the canonical way of accessing variables like $^T, with the caret form only being added as an alternative.
The literal control form is being deprecated for two main reasons. It has what are likely unfixable bugs, such as $\cI not working as an alias for $^I, and their usage not being portable to non-ASCII platforms: While $^T will work everywhere, \cT is whitespace in EBCDIC. [perl #119123]
Setting $/ to a reference to zero or a reference to a negative integer is now deprecated, and will behave exactly as though it was set to "undef". If you want slurp behavior set $/ to "undef" explicitly.
Setting $/ to a reference to a non integer is now forbidden and will throw an error. Perl has never documented what would happen in this context and while it used to behave the same as setting $/ to the address of the references in future it may behave differently, so we have forbidden this usage.
Use of any of these functions in the "POSIX" module is now deprecated: "isalnum", "isalpha", "iscntrl", "isdigit", "isgraph", "islower", "isprint", "ispunct", "isspace", "isupper", and "isxdigit". The functions are buggy and don't work on UTF-8 encoded strings. See their entries in POSIX for more information.
A warning is raised on the first call to any of them from each place in the code that they are called. (Hence a repeated statement in a loop will raise just the one warning.)
The "interpreter-based threads" provided by Perl are not the fast, lightweight system for multitasking that one might expect or hope for. Threads are implemented in a way that make them easy to misuse. Few people know how to use them correctly or will be able to provide help.
The use of interpreter-based threads in perl is officially discouraged.
The following modules will be removed from the core distribution in a future release, and will at that time need to be installed from CPAN. Distributions on CPAN which require these modules will need to list them as prerequisites.
The core versions of these modules will now issue "deprecated"-category warnings to alert you to this fact. To silence these deprecation warnings, install the modules in question from CPAN.
Note that the planned removal of these modules from core does not reflect a judgement about the quality of the code and should not be taken as a suggestion that their use be halted. Their disinclusion from core primarily hinges on their necessity to bootstrapping a fully functional, CPAN-capable Perl installation, not on concerns over their design.
The following utilities will be removed from the core distribution in a future release, and will at that time need to be installed from CPAN.
This feature was already available in 5.18.0, but wasn't enabled by default. It is the default now, and so you no longer need build perl with the Configure argument:
-Accflags=-DPERL_NEW_COPY_ON_WRITE
It can be disabled (for now) in a perl build with:
-Accflags=-DPERL_NO_COW
On some operating systems Perl can be compiled in such a way that any attempt to modify string buffers shared by multiple SVs will crash. This way XS authors can test that their modules handle copy-on-write scalars correctly. See "Copy on Write" in perlguts for detail.
sub baz { return $cat; }
will now behave like:
sub baz { $cat; }
which is notably faster.
[perl #120765]
my $x; # or @x, %x
my $y;
is now optimized to:
my ($x, $y);
In combination with the padrange optimization introduced in v5.18.0, this means longer uninitialized my variable statements are also optimized, so:
my $x; my @y; my %z;
becomes:
my ($x, @y, %z);
[perl #121077]
$OLD_PERL_VERSION was added as an alias of $].
perlrepository
This document was removed (actually, renamed perlgit and given a major overhaul) in Perl v5.14, causing Perl documentation websites to show the now out of date version in Perl v5.12 as the latest version. It has now been restored in stub form, directing readers to current information.
perldata
perldebguts
perlexperiment
perlfunc
perlguts
perlhack
perlhacktips
perllexwarn
perllocale
perlop
perlopentut
perlre
perlreguts
perlsub
perltrap
perlunicode
perlvar
(Actually, "OLD_PERL_VERSION" does exist, starting with this revision, but remained undocumented until perl 5.22.0.)
perlxs
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 Errors
(F) You used index/value array slice syntax (%array[...]) as the argument to "delete". You probably meant @array[...] with an @ symbol instead.
(F) You used key/value hash slice syntax (%hash{...}) as the argument to "delete". You probably meant @hash{...} with an @ symbol instead.
(F) You assigned a magical array to a stash element, and then tried to use the subroutine from the same slot. You are asking Perl to do something it cannot do, details subject to change between Perl versions.
New Warnings
The "auto-deref" feature is experimental.
Starting in v5.14.0, it was possible to use push, pop, keys, and other built-in functions not only on aggregate types, but on references to them. The feature was not deployed to its original intended specification, and now may become redundant to postfix dereferencing. It has always been categorized as an experimental feature, and in v5.20.0 is carries a warning as such.
Warnings will now be issued at compile time when these operations are detected.
no if $] >= 5.01908, warnings => "experimental::autoderef";
Consider, though, replacing the use of these features, as they may change behavior again before becoming stable.
Trailing white-space in a charnames alias definition is deprecated
These two deprecation warnings involving "\N{...}" were incorrectly implemented. They did not warn by default (now they do) and could not be made fatal via "use warnings FATAL => 'deprecated'" (now they can).
(W misc) A sub was declared as "sub foo : prototype(A) : prototype(B) {}", for example. Since each sub can only have one prototype, the earlier declaration(s) are discarded while the last one is applied.
(W syscalls) Embedded \0 characters in pathnames or other system call arguments produce a warning as of 5.20. The parts after the \0 were formerly ignored by system calls.
This replaces the message "Code point 0x%X is not Unicode, all \p{} matches fail; all \P{} matches succeed".
(W illegalproto) A grouping was started with "[" but never closed with "]".
(W syntax) There is a possible problem with the mixing of a control flow operator (e.g. "return") and a low-precedence operator like "or". Consider:
sub { return $a or $b; }
This is parsed as:
sub { (return $a) or $b; }
Which is effectively just:
sub { return $a; }
Either use parentheses or the high-precedence variant of the operator.
Note this may be also triggered for constructs like:
sub { 1 if die; }
(S experimental::postderef) This warning is emitted if you use the experimental postfix dereference syntax. 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::postderef";
use feature "postderef", "postderef_qq";
$ref->$*;
$aref->@*;
$aref->@[@indices];
... etc ...
(W prototype) A prototype was declared in both the parentheses after the sub name and via the prototype attribute. The prototype in parentheses is useless, since it will be replaced by the prototype from the attribute before it's ever used.
(W syntax) In scalar context, you've used an array index/value slice (indicated by %) to select a single element of an array. Generally it's better to ask for a scalar value (indicated by $). The difference is that $foo[&bar] always behaves like a scalar, both in the value it returns and when evaluating its argument, while %foo[&bar] provides a list context to its subscript, which can do weird things if you're expecting only one subscript. When called in list context, it also returns the index (what &bar returns) in addition to the value.
(W syntax) In scalar context, you've used a hash key/value slice (indicated by %) to select a single element of a hash. Generally it's better to ask for a scalar value (indicated by $). The difference is that $foo{&bar} always behaves like a scalar, both in the value it returns and when evaluating its argument, while @foo{&bar} and provides a list context to its subscript, which can do weird things if you're expecting only one subscript. When called in list context, it also returns the key in addition to the value.
(S) exit() was called or the script otherwise finished gracefully when "PERL_EXIT_WARN" was set in "PL_exit_flags".
(S) An uncaught die() was called when "PERL_EXIT_WARN" was set in "PL_exit_flags".
(D deprecated) Using literal control characters in the source to refer to the ^FOO variables, like $^X and ${^GLOBAL_PHASE} is now deprecated. This only affects code like $\cT, where \cT is a control (like a "SOH") in the source code: ${"\cT"} and $^T remain valid.
This fixes [Perl #42957].
Unknown switch condition (?(%s in regex;
But what %s could be was mostly up to luck. For "(?(foobar))", you might have seen "fo" or "f". For Unicode characters, you would generally get a corrupted string. The message has been changed to read:
Unknown switch condition (?(...)) in regex;
Additionally, the '<-- HERE' marker in the error will now point to the correct spot in the regex.
This message is now only in the regexp category, and not in the deprecated category. It is still a default (i.e., severe) warning [perl #89648].
This warning now occurs for any %array[$index] or %hash{key} known to be in scalar context at compile time. Previously it was worded "Scalar value %%s[%s] better written as $%s[%s]".
The description for this diagnostic has been extended to cover all cases where the warning may occur. Issues with the positioning of the arrow indicator have also been resolved.
a2p
bisect.pl
The git bisection tool Porting/bisect.pl has had many enhancements.
It is provided as part of the source distribution but not installed because it is not self-contained as it relies on being run from within a git checkout. Note also that it makes no attempt to fix tests, correct runtime bugs or make something useful to install - its purpose is to make minimal changes to get any historical revision of interest to build and run as close as possible to "as-was", and thereby make "git bisect" easy to use.
find2perl
perlbug
The behaviour for all valid documented invocations is unchanged.
When compiling perl with this option, the library files for XS modules are named something "unique" -- for example, Hash/Util/Util.so becomes Hash/Util/PL_Hash__Util.so. This behavior is similar to what currently happens on VMS, and serves as groundwork for the Android port.
When building with this option set, both Configure and the compilers search for all headers and libraries under this new sysroot, instead of /.
This is a huge time saver if cross-compiling, but can also help on native builds if your toolchain's files have non-standard locations.
We now build binaries for miniperl and generate_uudmap to be used on the host, rather than running every miniperl call on the target; this means that, short of 'make test', we no longer need access to the target system once Configure is done. You can provide already-built binaries through the "hostperl" and "hostgenerate" options to Configure.
Additionally, if targeting an EBCDIC platform from an ASCII host, or viceversa, you'll need to run Configure with "-Uhostgenerate", to indicate that generate_uudmap should be run on the target.
Finally, there's also a way of having Configure end early, right after building the host binaries, by cross-compiling without specifying a "targethost".
The incompatible changes include no longer using xconfig.h, xlib, or Cross.pm, so canned config files and Makefiles will have to be updated.
For example, Android has its sh in /system/bin/sh, so if cross-compiling from a more normal Unixy system with sh in /bin/sh, "targetsh" would end up as /system/bin/sh, and "sh" as /bin/sh.
Perl 5.004 added support to use the native API of "sfio", AT&T's Safe/Fast I/O library. This code still built with v5.8.0, albeit with many regression tests failing, but was inadvertently broken before the v5.8.1 release, meaning that it has not worked on any version of Perl released since then. In over a decade we have received no bug reports about this, hence it is clear that no-one is using this functionality on any version of Perl that is still supported to any degree.
Tests now handle the errors that occur when "cygserver" isn't running.
The ALL_STATIC option has also been improved to include the Encode and Win32 extensions (for both VC++ and MinGW builds).
Support for building with EVC (Embedded Visual C++) 4 has been restored. Perl can also be built using Smart Devices for Visual C++ 2005 or 2008.
Starting in this release, almost never does application code need to distinguish between the platform's character set and Latin1, on which the lowest 256 characters of Unicode are based. New code should not use "utf8n_to_uvuni" (use "utf8_to_uvchr_buf" instead), nor "uvuni_to_utf8" (use "uvchr_to_utf8" instead),
check.third check.utf16 check.utf8 coretest minitest.prep
minitest.utf16 perl.config.dashg perl.config.dashpg
perl.config.gcov perl.gcov perl.gprof perl.gprof.config
perl.pixie perl.pixie.atom perl.pixie.config perl.pixie.irix
perl.third perl.third.config perl.valgrind.config purecovperl
pureperl quantperl test.deparse test.taintwarn test.third
test.torture test.utf16 test.utf8 test_notty.deparse
test_notty.third test_notty.valgrind test_prep.third
test_prep.valgrind torturetest ucheck ucheck.third ucheck.utf16
ucheck.valgrind utest utest.third utest.utf16 utest.valgrind
It's still possible to run the relevant commands by "hand" - no underlying functionality has been removed.
For example:
$ perl -MDevel::Peek -e'$a="abc"; $b = $a; Dump $a; Dump $b'
SV = PV(0x260cd80) at 0x2620ad8
REFCNT = 1
FLAGS = (POK,IsCOW,pPOK)
PV = 0x2619bc0 "abc"\0
CUR = 3
LEN = 16
COW_REFCNT = 1
SV = PV(0x260ce30) at 0x2620b20
REFCNT = 1
FLAGS = (POK,IsCOW,pPOK)
PV = 0x2619bc0 "abc"\0
CUR = 3
LEN = 16
COW_REFCNT = 1
Note that both scalars share the same PV buffer and have a COW_REFCNT greater than zero.
This means that XS code which wishes to modify the "SvPVX()" buffer of an SV should call "SvPV_force()" or similar first, to ensure a valid (and unshared) buffer, and to call "SvSETMAGIC()" afterwards. This in fact has always been the case (for example hash keys were already copy-on-write); this change just spreads the COW behaviour to a wider variety of SVs.
One important difference is that before 5.18.0, shared hash-key scalars used to have the "SvREADONLY" flag set; this is no longer the case.
This new behaviour can still be disabled by running Configure with -Accflags=-DPERL_NO_COW. This option will probably be removed in Perl 5.22.
The previous behaviour can still be enabled by running Configure with -Accflags=-DPERL_SAWAMPERSAND.
The only way a NULL "sv" can be passed to sv_2*v* functions is if XS code directly calls sv_2*v*. This is unlikely as XS code uses Sv*V* macros to get the underlying value out of the SV. One possible situation which leads to a NULL "sv" being passed to sv_2*v* functions, is if XS code defines its own getter type Sv*V* macros, which check for NULL before dereferencing and checking the SV's flags through public API Sv*OK* macros or directly using private API "SvFLAGS", and if "sv" is NULL, then calling the sv_2*v functions with a NULL litteral or passing the "sv" containing a NULL value.
The public API newATTRSUB was previously a macro to the private function Perl_newATTRSUB. Function Perl_newATTRSUB has been removed. newATTRSUB is now macro to a different internal function.
This bottom level function decodes the first character of a UTF-8 string into a code point. It is accessible to "XS" level code, but it's discouraged from using it directly. There are higher level functions that call this that should be used instead, such as "utf8_to_uvchr_buf" in perlapi. For completeness though, this documents some changes to it. Now, tests for malformations are done before any tests for other potential issues. One of those issues involves code points so large that they have never appeared in any official standard (the current standard has scaled back the highest acceptable code point from earlier versions). It is possible (though not done in CPAN) to warn and/or forbid these code points, while accepting smaller code points that are still above the legal Unicode maximum. The warning message for this now includes the code point if representable on the machine. Previously it always displayed raw bytes, which is what it still does for non-representable code points.
Many flags that used to be exposed via regexp.h and used to populate the extflags member of struct regexp have been removed. These fields were technically private to Perl's own regexp engine and should not have been exposed there in the first place.
The affected flags are:
RXf_NOSCAN
RXf_CANY_SEEN
RXf_GPOS_SEEN
RXf_GPOS_FLOAT
RXf_ANCH_BOL
RXf_ANCH_MBOL
RXf_ANCH_SBOL
RXf_ANCH_GPOS
As well as the follow flag masks:
RXf_ANCH_SINGLE
RXf_ANCH
All have been renamed to PREGf_ equivalents and moved to regcomp.h.
The behavior previously achieved by setting one or more of the RXf_ANCH_ flags (via the RXf_ANCH mask) have now been replaced by a *single* flag bit in extflags:
RXf_IS_ANCHORED
pluggable regex engines which previously used to set these flags should now set this flag ALONE.
utf8::upgrade( my $u = "\x{e5}");
utf8::downgrade(my $d = "\x{e5}");
/$u$d/
[RT #118297]
This could occur for pseudo-forked processes too, as Win32's pseudo-fork is implemented in terms of threads. [perl #77672]
Diana Rosa, 27, of Rio de Janeiro, went to her long rest on May 10, 2014, along with the plush camel she kept hanging on her computer screen all the time. She was a passionate Perl hacker who loved the language and its community, and who never missed a Rio.pm event. She was a true artist, an enthusiast about writing code, singing arias and graffiting walls. We'll never forget you.
Greg McCarroll died on August 28, 2013.
Greg was well known for many good reasons. He was one of the organisers of the first YAPC::Europe, which concluded with an unscheduled auction where he frantically tried to raise extra money to avoid the conference making a loss. It was Greg who mistakenly arrived for a london.pm meeting a week late; some years later he was the one who sold the choice of official meeting date at a YAPC::Europe auction, and eventually as glorious leader of london.pm he got to inherit the irreverent confusion that he had created.
Always helpful, friendly and cheerfully optimistic, you will be missed, but never forgotten.
Perl 5.20.0 represents approximately 12 months of development since Perl 5.18.0 and contains approximately 470,000 lines of changes across 2,900 files from 124 authors.
Excluding auto-generated files, documentation and release tools, there were approximately 280,000 lines of changes to 1,800 .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 5.20.0:
Aaron Crane, Abhijit Menon-Sen, Abigail, Abir Viqar, Alan Haggai Alavi, Alan Hourihane, Alexander Voronov, Alexandr Ciornii, Andy Dougherty, Anno Siegel, Aristotle Pagaltzis, Arthur Axel 'fREW' Schmidt, Brad Gilbert, Brendan Byrd, Brian Childs, Brian Fraser, Brian Gottreu, Chris 'BinGOs' Williams, Christian Millour, Colin Kuskie, Craig A. Berry, Dabrien 'Dabe' Murphy, Dagfinn Ilmari Mannsåker, Daniel Dragan, Darin McBride, David Golden, David Leadbeater, David Mitchell, David Nicol, David Steinbrunner, Dennis Kaarsemaker, Dominic Hargreaves, Ed Avis, Eric Brine, Evan Zacks, Father Chrysostomos, Florian Ragwitz, François Perrad, Gavin Shelley, Gideon Israel Dsouza, Gisle Aas, Graham Knop, H.Merijn Brand, Hauke D, Heiko Eissfeldt, Hiroo Hayashi, Hojung Youn, James E Keenan, Jarkko Hietaniemi, Jerry D. Hedden, Jess Robinson, Jesse Luehrs, Johan Vromans, John Gardiner Myers, John Goodyear, John P. Linderman, John Peacock, kafka, Kang-min Liu, Karen Etheridge, Karl Williamson, Keedi Kim, Kent Fredric, kevin dawson, Kevin Falcone, Kevin Ryde, Leon Timmermans, Lukas Mai, Marc Simpson, Marcel Grünauer, Marco Peereboom, Marcus Holland-Moritz, Mark Jason Dominus, Martin McGrath, Matthew Horsfall, Max Maischein, Mike Doherty, Moritz Lenz, Nathan Glenn, Nathan Trapuzzano, Neil Bowers, Neil Williams, Nicholas Clark, Niels Thykier, Niko Tyni, Olivier Mengué, Owain G. Ainsworth, Paul Green, Paul Johnson, Peter John Acklam, Peter Martini, Peter Rabbitson, Petr Písař, Philip Boulain, Philip Guenther, Piotr Roszatycki, Rafael Garcia-Suarez, Reini Urban, Reuben Thomas, Ricardo Signes, Ruslan Zakirov, Sergey Alekseev, Shirakata Kentaro, Shlomi Fish, Slaven Rezic, Smylers, Steffen Müller, Steve Hay, Sullivan Beck, Thomas Sibley, Tobias Leich, Toby Inkster, Tokuhiro Matsuno, Tom Christiansen, Tom Hukins, Tony Cook, Victor Efimov, Viktor Turskyi, Vladimir Timofeev, YAMASHINA Hio, Yves Orton, Zefram, Zsbán Ambrus, Ævar Arnfjörð Bjarmason.
The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.
Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.
For a more complete list of all of Perl's historical contributors, please see the 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 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 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.
| 2020-07-21 | perl v5.28.1 |