man > perl5181delta(1)

PERL5181DELTA(1)                  Perl Programmers Reference Guide                  PERL5181DELTA(1)

NAME
       perl5181delta - what is new for perl v5.18.1

DESCRIPTION
       This document describes differences between the 5.18.0 release and the 5.18.1 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.

Incompatible Changes
       There are no changes intentionally incompatible with 5.18.0 If any exist, they are bugs, and
       we request that you submit a report.  See "Reporting Bugs" below.

Modules and Pragmata
   Updated Modules and Pragmata
       •   B has been upgraded from 1.42 to 1.42_01, fixing bugs related to lexical subroutines.

       •   Digest::SHA has been upgraded from 5.84 to 5.84_01, fixing a crashing bug.  [RT #118649]

       •   Module::CoreList has been upgraded from 2.89 to 2.96.

Platform Support
   Platform-Specific Notes
       AIX A rarely-encountered configuration bug in the AIX hints file has been corrected.

       MidnightBSD
           After  a patch to the relevant hints file, perl should now build correctly on MidnightBSD
           0.4-RELEASE.

Selected Bug Fixes
       •   Starting in v5.18.0, a construct  like  "/[#](?{})/x"  would  have  its  "#"  incorrectly
           interpreted  as  a  comment.   The  code block would be skipped, unparsed.  This has been
           corrected.

       •   A number of memory leaks related to the  new,  experimental  regexp  bracketed  character
           class feature have been plugged.

       •   The  OP  allocation  code  now  returns correctly aligned memory in all cases for "struct
           pmop". Previously it could return memory only aligned to a 4-byte boundary, which is  not
           correct  for  an  ithreads  build with 64 bit IVs on some 32 bit platforms. Notably, this
           caused the build to fail completely on sparc GNU/Linux. [RT #118055]

       •   The debugger's "man" command been fixed. It was broken in the v5.18.0 release. The  "man"
           command is aliased to the names "doc" and "perldoc" - all now work again.

       •   @_  is now correctly visible in the debugger, fixing a regression introduced in v5.18.0's
           debugger. [RT #118169]

       •   Fixed a small number of regexp constructions that could either fail  to  match  or  crash
           perl  when  the  string  being matched against was allocated above the 2GB line on 32-bit
           systems. [RT #118175]

       •   Perl v5.16 inadvertently introduced a bug whereby calls to XSUBs that were not visible at
           compile time were treated as lvalues and could be assigned to, even when  the  subroutine
           was not an lvalue sub.  This has been fixed.  [perl #117947]

       •   Perl  v5.18  inadvertently  introduced a bug whereby dual-vars (i.e.  variables with both
           string and numeric values, such  as  $!  )  where  the  truthness  of  the  variable  was
           determined by the numeric value rather than the string value. [RT #118159]

       •   Perl v5.18 inadvertently introduced a bug whereby interpolating mixed up- and down-graded
           UTF-8  strings in a regex could result in malformed UTF-8 in the pattern: specifically if
           a downgraded character in the range "\x80..\xff" followed a UTF-8 string, e.g.

               utf8::upgrade(  my $u = "\x{e5}");
               utf8::downgrade(my $d = "\x{e5}");
               /$u$d/

           [perl #118297].

       •   Lexical constants ("my sub a() { 42 }") no longer crash when inlined.

       •   Parameter prototypes attached to lexical subroutines are now respected when compiling sub
           calls without parentheses.  Previously, the prototypes were honoured only for calls  with
           parentheses. [RT #116735]

       •   Syntax errors in lexical subroutines in combination with calls to the same subroutines no
           longer cause crashes at compile time.

       •   The  dtrace  sub-entry  probe  now  works  with  lexical  subs, instead of crashing [perl
           #118305].

       •   Undefining an inlinable lexical subroutine (my sub foo() { 42 } undef &foo) would  result
           in a crash if warnings were turned on.

       •   Deep recursion warnings no longer crash lexical subroutines. [RT #118521]

Acknowledgements
       Perl  5.18.1  represents approximately 2 months of development since Perl 5.18.0 and contains
       approximately 8,400 lines of changes across 60 files from 12 authors.

       Perl continues to flourish into its third decade thanks to a vibrant community of  users  and
       developers.  The  following people are known to have contributed the improvements that became
       Perl 5.18.1:

       Chris 'BinGOs' Williams, Craig A. Berry, Dagfinn Ilmari  Mannsåker,  David  Mitchell,  Father
       Chrysostomos,  Karl  Williamson,  Lukas  Mai,  Nicholas Clark, Peter Martini, Ricardo Signes,
       Shlomi Fish, Tony Cook.

       The list above is almost certainly incomplete as it is automatically generated  from  version
       control  history. In particular, it does not include the names of the (very much appreciated)
       contributors who reported issues to the Perl bug tracker.

       Many of the changes included in this version originated  in  the  CPAN  modules  included  in
       Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.

       For  a  more  complete  list of all of Perl's historical contributors, please see the AUTHORS
       file in the Perl source distribution.

Reporting Bugs
       If you find what you think is a bug, you might check the  articles  recently  posted  to  the
       comp.lang.perl.misc  newsgroup  and  the  perl  bug database at http://rt.perl.org/perlbug/ .
       There may also be information at http://www.perl.org/ , the Perl Home Page.

       If you believe you have an unreported bug, please run the perlbug program included with  your
       release.  Be sure to trim your bug down to a tiny but sufficient test case.  Your bug report,
       along  with  the  output of "perl -V", will be sent off to perlbug AT 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 AT 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.

SEE ALSO
       The Changes file for an explanation of how to view exhaustive details on what changed.

       The INSTALL file for how to build Perl.

       The README file for general stuff.

       The Artistic and Copying files for copyright information.

perl v5.38.2                                 2026-06-12                             PERL5181DELTA(1)