This document describes differences between the 5.12.1 release and the
If you are upgrading from an earlier major version, such as 5.10.1,
first read perl5120delta, which describes differences between 5.10.1
and 5.12.0, as well as perl5121delta, which describes earlier changes
in the 5.12 stable release series.
There are no changes intentionally incompatible with 5.12.1. If any
exist, they are bugs and reports are welcome.
Other than the bug fixes listed below, there should be no user-visible
changes to the core language in this release.
Modules and Pragmata
New Modules and Pragmata
This release does not introduce any new modules or pragmata.
In the previous release, "no VERSION;" statements triggered a bug which
could cause feature bundles to be loaded and strict mode to be enabled
Upgraded from version 1.16 to 1.17.
Carp now detects incomplete caller() overrides and avoids using
bogus @DB::args. To provide backtraces, Carp relies on particular
behaviour of the caller built-in. Carp now detects if other code
has overridden this with an incomplete implementation, and modifies
its backtrace accordingly. Previously incomplete overrides would
cause incorrect values in backtraces (best case), or obscure fatal
errors (worst case)
This fixes certain cases of "Bizarre copy of ARRAY" caused by
modules overriding "caller()" incorrectly.
A patch to cpanp-run-perl has been backported from CPANPLUS 0.9004.
This resolves RT #55964
<http://rt.cpan.org/Public/Bug/Display.html?id=55964> and RT #57106
<http://rt.cpan.org/Public/Bug/Display.html?id=57106>, both of
which related to failures to install distributions that use
A regression which caused a failure to find "CORE::GLOBAL::glob"
after loading "File::Glob" to crash has been fixed. Now, it
correctly falls back to external globbing via "pp_glob".
properly handles Unix-style input.
o perlbug now always gives the reporter a chance to change the email
address it guesses for them.
o perlbug should no longer warn about uninitialized values when using
the "-d" and "-v" options.
Changes to Existing Documentation
o The existing policy on backward-compatibility and deprecation has
been added to perlpolicy, along with definitions of terms like
o "srand" in perlfunc's usage has been clarified.
o The entry for "die" in perlfunc was reorganized to emphasize its
role in the exception mechanism.
o Perl's INSTALL file has been clarified to explicitly state that
Perl requires a C89 compliant ANSI C Compiler.
o IO::Socket's "getsockopt()" and "setsockopt()" have been
o alarm()'s inability to interrupt blocking IO on Windows has been
o Math::TrulyRandom hasn't been updated since 1996 and has been
removed as a recommended solution for random number generation.
o perlrun has been updated to clarify the behaviour of octal flags to
o To ease user confusion, $# and $*, two special variables that were
removed in earlier versions of Perl have been documented.
o The version of perlfaq shipped with the Perl core has been updated
from the official FAQ version, which is now maintained in the
"briandfoy/perlfaq" branch of the Perl repository at
Installation and Configuration Improvements
o The "d_u32align" configuration probe on ARM has been fixed.
o An ""incompatible operand types"" error in ternary expressions when
building with "clang" has been fixed.
o Perl now skips setuid "File::Copy" tests on partitions it detects
to be mounted as "nosuid".
Selected Bug Fixes
checksum on the stack, as would "unpack("%2u", ...)". [perl
o Perl now avoids using memory after calling "free()" in pp_require
when there are CODEREFs in @INC.
o A bug that could cause ""Unknown error"" messages when
""call_sv(code, G_EVAL)"" is called from an XS destructor has been
o The implementation of the "open $fh, '>' \$buffer" feature now
supports get/set magic and thus tied buffers correctly.
o The "pp_getc", "pp_tell", and "pp_eof" opcodes now make room on the
stack for their return values in cases where no argument was passed
o When matching unicode strings under some conditions inappropriate
backtracking would result in a "Malformed UTF-8 character (fatal)"
error. This should no longer occur. See [perl #75680]
Platform Specific Notes
o README.aix has been updated with information about the XL C/C++ V11
o When building Perl with the mingw64 x64 cross-compiler "incpath",
"libpth", "ldflags", "lddlflags" and "ldflags_nolargefiles" values
in Config.pm and Config_heavy.pl were not previously being set
correctly because, with that compiler, the include and lib
directories are not immediately below "$(CCHOME)".
o git_version.h is now installed on VMS. This was an oversight in
v5.12.0 which caused some extensions to fail to build.
o Several memory leaks in stat() have been fixed.
o A memory leak in "Perl_rename()" due to a double allocation has
o A memory leak in "vms_fid_to_name()" (used by "realpath()" and
"realname()") has been fixed.
Perl 5.12.2 represents approximately three months of development since
Perl 5.12.1 and contains approximately 2,000 lines of changes across
100 files from 36 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 5.12.2:
If you find what you think is a bug, you might check the articles
recently posted to the comp.lang.perl.misc newsgroup and the perl bug
database at http://rt.perl.org/perlbug/ . There may also be
information at http://www.perl.org/ , the Perl Home Page.
If you believe you have an unreported bug, please run the perlbug
program included with your release. Be sure to trim your bug down to a
tiny but sufficient test case. Your bug report, along with the output
of "perl -V", will be sent off to email@example.com to be analysed by
the Perl porting team.
If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please
send it to firstname.lastname@example.org. This points to a closed
subscription unarchived mailing list, which includes all the core
committers, who 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.
perl v5.14.2 2011-09-26 PERL5122DELTA(1)
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