The isa Operator¶

A new experimental infix operator called "isa" tests whether a given object is an instance of a given class or a class derived from it:

    if( $obj isa Package::Name ) { ... }

For more detail see "Class Instance Operator" in perlop.

Unicode 13.0 is supported¶

See <https://www.unicode.org/versions/Unicode13.0.0/> for details.

Chained comparisons capability¶

Some comparison operators, as their associativity, chain with some operators of the same precedence (but never with operators of different precedence).

    if ( $x < $y <= $z ) {...}

behaves exactly like:

    if ( $x < $y && $y <= $z ) {...}

(assuming that "$y" is as simple a scalar as it looks.)

You can read more about this in perlop under "Operator Precedence and Associativity" in perlop.

New Unicode properties "Identifier_Status" and "Identifier_Type" supported¶

Unicode has revised its regular expression requirements: <https://www.unicode.org/reports/tr18/tr18-21.html>. As part of that they are wanting more properties to be exposed, ones that aren't part of the strict UCD (Unicode character database). These two are used for examining inputs for security purposes. Details on their usage is at <https://www.unicode.org/reports/tr39/>.

It is now possible to write "qr/\p{Name=...}/", or "qr!\p{na=/(SMILING|GRINNING) FACE/}!"¶

The Unicode Name property is now accessible in regular expression patterns, as an alternative to "\N{...}". A comparison of the two methods is given in "Comparison of \N{...} and \p{name=...}" in perlunicode.

The second example above shows that wildcard subpatterns are also usable in this property. See "Wildcards in Property Values" in perlunicode.

Improvement of "POSIX::mblen()", "mbtowc", and "wctomb"¶

The "POSIX::mblen()", "mbtowc", and "wctomb" functions now work on shift state locales and are thread-safe on C99 and above compilers when executed on a platform that has locale thread-safety; the length parameters are now optional.

These functions are always executed under the current C language locale. (See perllocale.) Most locales are stateless, but a few, notably the very rarely encountered ISO 2022, maintain a state between calls to these functions. Previously the state was cleared on every call, but now the state is not reset unless the appropriate parameter is "undef".

On threaded perls, the C99 functions mbrlen(3), mbrtowc(3), and wcrtomb(3), when available, are substituted for the plain functions. This makes these functions thread-safe when executing on a locale thread-safe platform.

The string length parameters in "mblen" and "mbtowc" are now optional; useful only if you wish to restrict the length parsed in the source string to less than the actual length.

Alpha assertions are no longer experimental¶

See "(*pla:pattern)" in perlre, "(*plb:pattern)" in perlre, "(*nla:pattern)" in perlre>, and "(*nlb:pattern)" in perlre. Use of these no longer generates a warning; existing code that disables the warning category "experimental::alpha_assertions" will continue to work without any changes needed. Enabling the category has no effect.

Script runs are no longer experimental¶

See "Script Runs" in perlre. Use of these no longer generates a warning; existing code that disables the warning category "experimental::script_run" will continue to work without any changes needed. Enabling the category has no effect.

Feature checks are now faster¶

Previously feature checks in the parser required a hash lookup when features were set outside of a feature bundle, this has been optimized to a bit mask check. [GH #17229 <https://github.com/Perl/perl5/issues/17229>]

Perl is now developed on GitHub¶

Perl is now developed on GitHub. You can find us at <https://github.com/Perl/perl5>.

Non-security bugs should now be reported via GitHub. Security issues should continue to be reported as documented in perlsec.

Compiled patterns can now be dumped before optimization¶

This is primarily useful for tracking down bugs in the regular expression compiler. This dump happens on "-DDEBUGGING" perls, if you specify "-Drv" on the command line; or on any perl if the pattern is compiled within the scope of "use re qw(Debug DUMP_PRE_OPTIMIZE)" or "use re qw(Debug COMPILE EXTRA)". (All but the second case display other information as well.)

[CVE-2020-10543] Buffer overflow caused by a crafted regular expression¶

A signed "size_t" integer overflow in the storage space calculations for nested regular expression quantifiers could cause a heap buffer overflow in Perl's regular expression compiler that overwrites memory allocated after the regular expression storage space with attacker supplied data.

The target system needs a sufficient amount of memory to allocate partial expansions of the nested quantifiers prior to the overflow occurring. This requirement is unlikely to be met on 64-bit systems.

Discovered by: ManhND of The Tarantula Team, VinCSS (a member of Vingroup).

[CVE-2020-10878] Integer overflow via malformed bytecode produced by a crafted regular expression¶

Integer overflows in the calculation of offsets between instructions for the regular expression engine could cause corruption of the intermediate language state of a compiled regular expression. An attacker could abuse this behaviour to insert instructions into the compiled form of a Perl regular expression.

Discovered by: Hugo van der Sanden and Slaven Rezic.

[CVE-2020-12723] Buffer overflow caused by a crafted regular expression¶

Recursive calls to "S_study_chunk()" by Perl's regular expression compiler to optimize the intermediate language representation of a regular expression could cause corruption of the intermediate language state of a compiled regular expression.

Discovered by: Sergey Aleynikov.

Additional Note¶

An application written in Perl would only be vulnerable to any of the above flaws if it evaluates regular expressions supplied by the attacker. Evaluating regular expressions in this fashion is known to be dangerous since the regular expression engine does not protect against denial of service attacks in this usage scenario.

Certain pattern matching features are now prohibited in compiling Unicode property value wildcard subpatterns¶

These few features are either inappropriate or interfere with the algorithm used to accomplish this task. The complete list is in "Wildcards in Property Values" in perlunicode.

Unused functions "POSIX::mbstowcs" and "POSIX::wcstombs" are removed¶

These functions could never have worked due to a defective interface specification. There is clearly no demand for them, given that no one has ever complained in the many years the functions were claimed to be available, hence so-called "support" for them is now dropped.

A bug fix for "(?[...])" may have caused some patterns to no longer compile¶

See "Selected Bug Fixes". The heuristics previously used may have let some constructs compile (perhaps not with the programmer's intended effect) that should have been errors. None are known, but it is possible that some erroneous constructs no longer compile.

"\p{user-defined}" properties now always override official Unicode ones¶

Previously, if and only if a user-defined property was declared prior to the compilation of the regular expression pattern that contains it, its definition was used instead of any official Unicode property with the same name. Now, it always overrides the official property. This change could break existing code that relied (likely unwittingly) on the previous behavior. Without this fix, if Unicode released a new version with a new property that happens to have the same name as the one you had long been using, your program would break when you upgraded to a perl that used that new Unicode version. See "User-Defined Character Properties" in perlunicode. [GH #17205 <https://github.com/Perl/perl5/issues/17205>]

Modifiable variables are no longer permitted in constants¶

Code like:

    my $var;
    $sub = sub () { $var };

where $var is referenced elsewhere in some sort of modifiable context now produces an exception when the sub is defined.

This error can be avoided by adding a return to the sub definition:

    $sub = sub () { return $var };

This has been deprecated since Perl 5.22. [perl #134138 <https://rt.perl.org/Ticket/Display.html?id=134138>]

Use of "vec" on strings with code points above 0xFF is forbidden¶

Such strings are represented internally in UTF-8, and "vec" is a bit-oriented operation that will likely give unexpected results on those strings. This was deprecated in perl 5.28.0.

Use of code points over 0xFF in string bitwise operators¶

Some uses of these were already illegal after a previous deprecation cycle. The remaining uses are now prohibited, having been deprecated in perl 5.28.0. See perldeprecation.

"Sys::Hostname::hostname()" does not accept arguments¶

This usage was deprecated in perl 5.28.0 and is now fatal.

Plain "0" string now treated as a number for range operator¶

Previously a range "0" .. "-1" would produce a range of numeric strings from "0" through "99"; this now produces an empty list, just as "0 .. -1" does. This also means that "0" .. "9" now produces a list of integers, where previously it would produce a list of strings.

This was due to a special case that treated strings starting with "0" as strings so ranges like "00" .. "03" produced "00", "01", "02", "03", but didn't specially handle the string "0". [perl #133695 <https://rt.perl.org/Ticket/Display.html?id=133695>]

"\K" now disallowed in look-ahead and look-behind assertions¶

This was disallowed because it causes unexpected behaviour, and no-one could define what the desired behaviour should be. [perl #124256 <https://rt.perl.org/Ticket/Display.html?id=124256>]

Updated Modules and Pragmata¶

• Archive::Tar has been upgraded from version 2.32 to 2.36.
• autodie has been upgraded from version 2.29 to 2.32.
• B has been upgraded from version 1.76 to 1.80.
• B::Deparse has been upgraded from version 1.49 to 1.54.
• Benchmark has been upgraded from version 1.22 to 1.23.
• charnames has been upgraded from version 1.45 to 1.48.
• Class::Struct has been upgraded from version 0.65 to 0.66.
• Compress::Raw::Bzip2 has been upgraded from version 2.084 to 2.093.
• Compress::Raw::Zlib has been upgraded from version 2.084 to 2.093.
• CPAN has been upgraded from version 2.22 to 2.27.
• DB_File has been upgraded from version 1.843 to 1.853.
• Devel::PPPort has been upgraded from version 3.52 to 3.57.

  The test files generated on Win32 are now identical to when they are generated on POSIX-like systems.

• diagnostics has been upgraded from version 1.36 to 1.37.
• Digest::MD5 has been upgraded from version 2.55 to 2.55_01.
• Dumpvalue has been upgraded from version 1.18 to 1.21.

  Previously, when dumping elements of an array and encountering an undefined value, the string printed would have been "empty array". This has been changed to what was apparently originally intended: "empty slot".

• DynaLoader has been upgraded from version 1.45 to 1.47.
• Encode has been upgraded from version 3.01 to 3.06.
• encoding has been upgraded from version 2.22 to 3.00.
• English has been upgraded from version 1.10 to 1.11.
• Exporter has been upgraded from version 5.73 to 5.74.
• ExtUtils::CBuilder has been upgraded from version 0.280231 to 0.280234.
• ExtUtils::MakeMaker has been upgraded from version 7.34 to 7.44.
• feature has been upgraded from version 1.54 to 1.58.

  A new "indirect" feature has been added, which is enabled by default but allows turning off indirect object syntax.

• File::Find has been upgraded from version 1.36 to 1.37.

  On Win32, the tests no longer require either a file in the drive root directory, or a writable root directory.

• File::Glob has been upgraded from version 1.32 to 1.33.
• File::stat has been upgraded from version 1.08 to 1.09.
• Filter::Simple has been upgraded from version 0.95 to 0.96.
• Getopt::Long has been upgraded from version 2.5 to 2.51.
• Hash::Util has been upgraded from version 0.22 to 0.23.

  The Synopsis has been updated as the example code stopped working with newer perls. [GH #17399 <https://github.com/Perl/perl5/issues/17399>]

• I18N::Langinfo has been upgraded from version 0.18 to 0.19.
• I18N::LangTags has been upgraded from version 0.43 to 0.44.

  Document the "IGNORE_WIN32_LOCALE" environment variable.

• IO has been upgraded from version 1.40 to 1.43.

  IO::Socket no longer caches a zero protocol value, since this indicates that the implementation will select a protocol. This means that on platforms that don't implement "SO_PROTOCOL" for a given socket type the protocol method may return "undef".

  The supplied TO is now always honoured on calls to the "send()" method. [perl #133936 <https://rt.perl.org/Ticket/Display.html?id=133936>]

• IO-Compress has been upgraded from version 2.084 to 2.093.
• IPC::Cmd has been upgraded from version 1.02 to 1.04.
• IPC::Open3 has been upgraded from version 1.20 to 1.21.
• JSON::PP has been upgraded from version 4.02 to 4.04.
• Math::BigInt has been upgraded from version 1.999816 to 1.999818.
• Math::BigInt::FastCalc has been upgraded from version 0.5008 to 0.5009.
• Module::CoreList has been upgraded from version 5.20190522 to 5.20200620.
• Module::Load::Conditional has been upgraded from version 0.68 to 0.70.
• Module::Metadata has been upgraded from version 1.000036 to 1.000037.
• mro has been upgraded from version 1.22 to 1.23.
• Net::Ping has been upgraded from version 2.71 to 2.72.
• Opcode has been upgraded from version 1.43 to 1.47.
• open has been upgraded from version 1.11 to 1.12.
• overload has been upgraded from version 1.30 to 1.31.
• parent has been upgraded from version 0.237 to 0.238.
• perlfaq has been upgraded from version 5.20190126 to 5.20200523.
• PerlIO has been upgraded from version 1.10 to 1.11.
• PerlIO::encoding has been upgraded from version 0.27 to 0.28.
• PerlIO::via has been upgraded from version 0.17 to 0.18.
• Pod::Html has been upgraded from version 1.24 to 1.25.
• Pod::Simple has been upgraded from version 3.35 to 3.40.
• podlators has been upgraded from version 4.11 to 4.14.
• POSIX has been upgraded from version 1.88 to 1.94.
• re has been upgraded from version 0.37 to 0.40.
• Safe has been upgraded from version 2.40 to 2.41.
• Scalar::Util has been upgraded from version 1.50 to 1.55.
• SelfLoader has been upgraded from version 1.25 to 1.26.
• Socket has been upgraded from version 2.027 to 2.029.
• Storable has been upgraded from version 3.15 to 3.21.

  Use of "note()" from Test::More is now optional in tests. This works around a circular dependency with Test::More when installing on very old perls from CPAN.

  Vstring magic strings over 2GB are now disallowed.

  Regular expressions objects weren't properly counted for object id purposes on retrieve. This would corrupt the resulting structure, or cause a runtime error in some cases. [perl #134179 <https://rt.perl.org/Ticket/Display.html?id=134179>]

• Sys::Hostname has been upgraded from version 1.22 to 1.23.
• Sys::Syslog has been upgraded from version 0.35 to 0.36.
• Term::ANSIColor has been upgraded from version 4.06 to 5.01.
• Test::Simple has been upgraded from version 1.302162 to 1.302175.
• Thread has been upgraded from version 3.04 to 3.05.
• Thread::Queue has been upgraded from version 3.13 to 3.14.
• threads has been upgraded from version 2.22 to 2.25.
• threads::shared has been upgraded from version 1.60 to 1.61.
• Tie::File has been upgraded from version 1.02 to 1.06.
• Tie::Hash::NamedCapture has been upgraded from version 0.10 to 0.13.
• Tie::Scalar has been upgraded from version 1.04 to 1.05.
• Tie::StdHandle has been upgraded from version 4.5 to 4.6.
• Time::HiRes has been upgraded from version 1.9760 to 1.9764.

  Removed obsolete code such as support for pre-5.6 perl and classic MacOS. [perl #134288 <https://rt.perl.org/Ticket/Display.html?id=134288>]

• Time::Piece has been upgraded from version 1.33 to 1.3401.
• Unicode::Normalize has been upgraded from version 1.26 to 1.27.
• Unicode::UCD has been upgraded from version 0.72 to 0.75.
• VMS::Stdio has been upgraded from version 2.44 to 2.45.
• warnings has been upgraded from version 1.44 to 1.47.
• Win32 has been upgraded from version 0.52 to 0.53.
• Win32API::File has been upgraded from version 0.1203 to 0.1203_01.
• XS::APItest has been upgraded from version 1.00 to 1.09.

Removed Modules and Pragmata¶

•

Pod::Parser has been removed from the core distribution. It still is available for download from CPAN. This resolves [perl #119439 <https://rt.perl.org/Ticket/Display.html?id=119439>].

Changes to Existing Documentation¶

We have attempted to update the documentation to reflect the changes listed in this document. If you find any we have missed, open an issue at <https://github.com/Perl/perl5/issues>.

Additionally, the following selected changes have been made:

perldebguts

• Simplify a few regnode definitions

  Update "BOUND" and "NBOUND" definitions.

• Add ANYOFHs regnode

  This node is like "ANYOFHb", but is used when more than one leading byte is the same in all the matched code points.

  "ANYOFHb" is used to avoid having to convert from UTF-8 to code point for something that won't match. It checks that the first byte in the UTF-8 encoded target is the desired one, thus ruling out most of the possible code points.

perlapi

• "sv_2pvbyte" updated to mention it will croak if the SV cannot be downgraded.
• "sv_setpvn" updated to mention that the UTF-8 flag will not be changed by this function, and a terminating NUL byte is guaranteed.
• Documentation for "PL_phase" has been added.
• The documentation for "grok_bin", "grok_oct", and "grok_hex" has been updated and clarified.

perldiag

•

Add documentation for experimental 'isa' operator

(S experimental::isa) This warning is emitted if you use the ("isa") operator. This operator is currently experimental and its behaviour may change in future releases of Perl.

perlfunc

"caller"

Like "__FILE__" and "__LINE__", the filename and line number returned here may be altered by the mechanism described at "Plain Old Comments (Not!)" in perlsyn.

"__FILE__"

It can be altered by the mechanism described at "Plain Old Comments (Not!)" in perlsyn.

"__LINE__"

It can be altered by the mechanism described at "Plain Old Comments (Not!)" in perlsyn.

"return"

Now mentions that you cannot return from "do BLOCK".

"open"

The "open()" section had been renovated significantly.

perlguts

• No longer suggesting using perl's "malloc". Modern system "malloc" is assumed to be much better than perl's implementation now.
• Documentation about embed.fnc flags has been removed. embed.fnc now has sufficient comments within it. Anyone changing that file will see those comments first, so entries here are now redundant.
• Updated documentation for "UTF8f"
• Added missing "=for apidoc" lines

perlhacktips

•

The differences between Perl strings and C strings are now detailed.

perlintro

•

The documentation for the repetition operator "x" have been clarified. [GH #17335 <https://github.com/Perl/perl5/issues/17335>]

perlipc

• The documentation surrounding "open" and handle usage has been modernized to prefer 3-arg open and lexical variables instead of barewords.
• Various updates and fixes including making all examples strict-safe and replacing "-w" with "use warnings".

perlop

•

'isa' operator is experimental

This is an experimental feature and is available when enabled by "use feature 'isa'". It emits a warning in the "experimental::isa" category.

perlpod

• Details of the various stacks within the perl interpreter are now explained here.
• Advice has been added regarding the usage of "Z<>".

perlport

•

Update "timegm" example to use the correct year format 1970 instead of 70. [GH #16431 <https://github.com/Perl/perl5/issues/16431>]

perlreref

•

Fix some typos.

perlvar

•

Now recommends stringifying $] and comparing it numerically.

perlapi, perlintern

•

Documentation has been added for several functions that were lacking it before.

perlxs

•

Suggest using "libffi" for simple library bindings via CPAN modules like FFI::Platypus or FFI::Raw.

POSIX

• "setlocale" warning about threaded builds updated to note it does not apply on Perl 5.28.X and later.
• "Posix::SigSet->new(...)" updated to state it throws an error if any of the supplied signals cannot be added to the set.

Additionally, the following selected changes have been made:

Updating of links

• Links to the now defunct <https://search.cpan.org> site now point at the equivalent <https://metacpan.org> URL. [GH #17393 <https://github.com/Perl/perl5/issues/17393>]
• The man page for ExtUtils::XSSymSet is now only installed on VMS, which is the only platform the module is installed on. [GH #17424 <https://github.com/Perl/perl5/issues/17424>]
• URLs have been changed to "https://" and stale links have been updated.

  Where applicable, the URLs in the documentation have been moved from using the "http://" protocol to "https://". This also affects the location of the bug tracker at <https://rt.perl.org>.

• Some links to OS/2 libraries, Address Sanitizer and other system tools had gone stale. These have been updated with working links.
• Some links to old email addresses on perl5-porters had gone stale. These have been updated with working links.

New Diagnostics¶

New Errors

• Expecting interpolated extended charclass in regex; marked by <-- HERE in m/%s/

  This is a replacement for several error messages listed under "Changes to Existing Diagnostics".

• "No digits found for %s literal"

  (F) No hexadecimal digits were found following "0x" or no binary digits were found following "0b".

New Warnings

• Code point 0x%X is not Unicode, and not portable

  This is actually not a new message, but it is now output when the warnings category "portable" is enabled.

  When raised during regular expression pattern compilation, the warning has extra text added at the end marking where precisely in the pattern it occurred.

• Non-hex character '%c' terminates \x early. Resolved as "%s"

  This replaces a warning that was much less specific, and which gave false information. This new warning parallels the similar already-existing one raised for "\o{}".

Changes to Existing Diagnostics¶

• Character following "\c" must be printable ASCII

  ...now has extra text added at the end, when raised during regular expression pattern compilation, marking where precisely in the pattern it occurred.

• Use "%s" instead of "%s"

  ...now has extra text added at the end, when raised during regular expression pattern compilation, marking where precisely in the pattern it occurred.

• Sequence "\c{" invalid

  ...now has extra text added at the end, when raised during regular expression pattern compilation, marking where precisely in the pattern it occurred.

• "\c%c" is more clearly written simply as "%s"

  ...now has extra text added at the end, when raised during regular expression pattern compilation, marking where precisely in the pattern it occurred.

• Non-octal character '%c' terminates \o early. Resolved as "%s"

  ...now includes the phrase "terminates \o early", and has extra text added at the end, when raised during regular expression pattern compilation, marking where precisely in the pattern it occurred. In some instances the text of the resolution has been clarified.

• '%s' resolved to '\o{%s}%d'

  As of Perl 5.32, this message is no longer generated. Instead, "Non-octal character '%c' terminates \o early. Resolved as "%s"" in perldiag is used instead.

• Use of code point 0x%s is not allowed; the permissible max is 0x%X

  Some instances of this message previously output the hex digits "A", "B", "C", "D", "E", and "F" in lower case. Now they are all consistently upper case.

• The following three diagnostics have been removed, and replaced by "Expecting interpolated extended charclass in regex; marked by <-- HERE in m/%s/" : "Expecting close paren for nested extended charclass in regex; marked by <-- HERE in m/%s/", "Expecting close paren for wrapper for nested extended charclass in regex; marked by <-- HERE in m/%s/", and "Expecting '(?flags:(?[...' in regex; marked by <-- HERE in m/%s/".
• The "Code point 0x%X is not Unicode, and not portable" warning removed the line "Code points above 0xFFFF_FFFF require larger than a 32 bit word." as code points that large are no longer legal on 32-bit platforms.
• Can't use global %s in %s

  This error message has been slightly reformatted from the original "Can't use global %s in "%s"", and in particular misleading error messages like "Can't use global $_ in "my"" are now rendered as "Can't use global $_ in subroutine signature".

• Constants from lexical variables potentially modified elsewhere are no longer permitted

  This error message replaces the former "Constants from lexical variables potentially modified elsewhere are deprecated. This will not be allowed in Perl 5.32" to reflect the fact that this previously deprecated usage has now been transformed into an exception. The message's classification has also been updated from D (deprecated) to F (fatal).

  See also "Incompatible Changes".

• "\N{} here is restricted to one character" is now emitted in the same circumstances where previously "\N{} in inverted character class or as a range end-point is restricted to one character" was.

  This is due to new circumstances having been added in Perl 5.30 that weren't covered by the earlier wording.

perlbug¶

•

The bug tracker homepage URL now points to GitHub.

streamzip¶

•

This is a new utility, included as part of an IO::Compress::Base upgrade.

streamzip creates a zip file from stdin. The program will read data from stdin, compress it into a zip container and, by default, write a streamed zip file to stdout.

Configure¶

• For clang++, add "#include <stdlib.h>" to Configure's probes for "futimes", "strtoll", "strtoul", "strtoull", "strtouq", otherwise the probes would fail to compile.
• Use a compile and run test for "lchown" to satisfy clang++ which should more reliably detect it.
• For C++ compilers, add "#include <stdio.h>" to Configure's probes for "getpgrp" and "setpgrp" as they use printf and C++ compilers may fail compilation instead of just warning.
• Check if the compiler can handle inline attribute.
• Check for character data alignment.
• Configure now correctly handles gcc-10. Previously it was interpreting it as gcc-1 and turned on "-fpcc-struct-return".
• Perl now no longer probes for "d_u32align", defaulting to "define" on all platforms. This check was error-prone when it was done, which was on 32-bit platforms only. [perl #133495 <https://rt.perl.org/Ticket/Display.html?id=133495>]
• Documentation and hints for building perl on Z/OS (native EBCDIC) have been updated. This is still a work in progress.
• A new probe for "malloc_usable_size" has been added.
• Improvements in Configure to detection in C++ and clang++. Work ongoing by Andy Dougherty. [perl #134171 <https://rt.perl.org/Ticket/Display.html?id=134171>]
• autodoc.pl

  This tool that regenerates perlintern and perlapi has been overhauled significantly, restoring consistency in flags used in embed.fnc and Devel::PPPort and allowing removal of many redundant "=for apidoc" entries in code.

• The "ECHO" macro is now defined. This is used in a "dtrace" rule that was originally changed for FreeBSD, and the FreeBSD make apparently predefines it. The Solaris make does not predefine "ECHO" which broke this rule on Solaris. [perl #134218 <https://rt.perl.org/Ticket/Display.html?id=134218>]
• Bison versions 3.1 through 3.4 are now supported.

Discontinued Platforms¶

Windows CE

Support for building perl on Windows CE has now been removed.

Platform-Specific Notes¶

Linux

"cc" will be used to populate "plibpth" if "cc" is "clang". [perl #134189 <https://rt.perl.org/Ticket/Display.html?id=134189>]

NetBSD 8.0

Fix compilation of Perl on NetBSD 8.0 with g++. [GH #17381 <https://github.com/Perl/perl5/issues/17381>]

Windows

Solaris

VMS

z/OS

Perl 5.32 has been tested on z/OS 2.4, with the following caveats: