PERL5231DELTA(1) Perl Programmers Reference Guide PERL5231DELTA(1)NAMEperl5231delta - what is new for perl v5.23.1
DESCRIPTION
This document describes differences between the 5.23.0 release and the
5.23.1 release.
If you are upgrading from an earlier release such as 5.22.0, first read
perl5230delta, which describes differences between 5.22.0 and 5.23.0.
Core Enhancements
Integer shift ("<<" and ">>") now more explicitly defined
Negative shifts are reverse shifts: left shift becomes right shift, and
right shift becomes left shift.
Shifting by the number of bits in a native integer (or more) is zero,
except when the "overshift" is right shifting a negative value under
"use integer", in which case the result is -1 (arithmetic shift).
Until now negative shifting and overshifting have been undefined
because they have relied on whatever the C implementation happens to
do. For example, for the overshift a common C behavior is "modulo
shift":
1 >> 64 == 1 >> (64 % 64) == 1 >> 0 == 1 # Common C behavior.
# And the same for <<, while Perl now produces 0 for both.
Now these behaviors are well-defined under Perl, regardless of what the
underlying C implementation does. Note, however, that you cannot
escape the native integer width, you need to know how far left you can
go. You can use for example:
use Config;
my $wordbits = $Config{uvsize} * 8; # Or $Config{uvsize} << 3.
If you need a more bits on the left shift, you can use for example the
"bigint" pragma, or the "Bit::Vector" module from CPAN.
Postfix dereferencing is no longer experimental
Using the "postderef" and "postderef_qq" features no longer emits a
warning. Existing code that disables the "experimental::postderef"
warning category that they previously used will continue to work. The
"postderef" feature has no effect; all Perl code can use postfix
dereferencing, regardless of what feature declarations are in scope.
The 5.24 feature bundle now includes the "postderef_qq" feature.
printf and sprintf now allow reordered precision arguments
That is, "sprintf '|%.*2$|', 2, 3" now returns "|002|". This extends
the existing reordering mechanism (which allows reordering for
arguments that are used as format fields, widths, and vector
separators).
Incompatible Changes
ASCII characters in variable names must now be all visible
It was legal until now on ASCII platforms for variable names to contain
non-graphical ASCII control characters (ordinals 0 through 31, and 127,
which are the C0 controls and "DELETE"). This usage has been
deprecated since v5.20, and as of now causes a syntax error. The
variables these names referred to are special, reserved by Perl for
whatever use it may choose, now, or in the future. Each such variable
has an alternative way of spelling it. Instead of the single non-
graphic control character, a two character sequence beginning with a
caret is used, like $^] and "${^GLOBAL_PHASE}". Details are at
perlvar. It remains legal, though unwise and deprecated (raising a
deprecation warning), to use certain non-graphic non-ASCII characters
in variables names when not under "use utf8". No code should do this,
as all such variables are reserved by Perl, and Perl doesn't currently
define any of them (but could at any time, without notice).
The "autoderef" feature has been removed
The experimental "autoderef" feature (which allowed calling "push",
"pop", "shift", "unshift", "splice", "keys", "values", and "each" on a
scalar argument) has been deemed unsuccessful. It has now been removed;
trying to use the feature (or to disable the "experimental::autoderef"
warning it previously triggered) now yields an exception.
Modules and Pragmata
Updated Modules and Pragmata
· The libnet distribution has been upgraded from version 3.06 to
3.07.
· autodie has been upgraded from version 2.27 to 2.29.
· DynaLoader has been upgraded from version 1.32 to 1.33.
· Encode has been upgraded from version 2.73 to 2.75.
· encoding has been upgraded from version 2.15 to 2.16.
· feature has been upgraded from version 1.41 to 1.42.
· File::Path has been upgraded from version 2.09 to 2.11.
· Getopt::Long has been upgraded from version 2.46 to 2.47.
· I18N::Langinfo has been upgraded from version 0.12 to 0.13.
· IPC::Open3 has been upgraded from version 1.18 to 1.19.
If a Perl exception was thrown from inside this module, the
exception "IPC::Open3" threw to the callers of "open3" would have
an irrelevant message derived from $! which was in an undefined
state, instead of the $@ message which triggers the failure path
inside "open3".
· Module::CoreList has been upgraded from version 5.20150620 to
5.20150720.
· Opcode has been upgraded from version 1.32 to 1.33.
· PerlIO::scalar has been upgraded from version 0.22 to 0.23.
· POSIX has been upgraded from version 1.54 to 1.55.
· Socket has been upgraded from version 2.019 to 2.020.
· Storable has been upgraded from version 2.53 to 2.54.
· Unicode::Collate has been upgraded from version 1.12 to 1.14.
· Unicode::Normalize has been upgraded from version 1.18 to 1.19.
· warnings has been upgraded from version 1.32 to 1.33.
· XS::Typemap has been upgraded from version 0.13 to 0.14.
Diagnostics
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.
Changes to Existing Diagnostics
· The "printf" and "sprintf" builtins are now more careful about the
warnings they emit: argument reordering now disables the "redundant
argument" warning in all cases; and invalid format strings are no
longer treated as absorbing arguments (so "redundant argument"
warnings can correctly be emitted by such code).
Platform Support
Platform-Specific Notes
VMS
· The minimum supported version of VMS is now v7.3-2, released in
2003. As a side effect of this change, VAX is no longer
supported as the terminal release of OpenVMS VAX was v7.3 in
2001.
Internal Changes
· "sv_catpvf" and related functions (including "sv_vcatpvfn_flags"
when called with a "va_list" rather than an array of SV pointers)
have never handled argument reordering. Attempts to reorder
arguments now yield an exception, rather than being silently
ignored.
Selected Bug Fixes
· A leak in the XS typemap caused one scalar to be leaked each time a
"FILE *" or a "PerlIO *" was "OUTPUT:"ed or imported to Perl, since
perl 5.000. These particular typemap entries are thought to be
extremely rarely used by XS modules. [perl #124181]
· "alarm()" and "sleep()" will now warn if the argument is a negative
number and return undef. Previously they would pass the negative
value to the underlying C function which may have set up a timer
with a surprising value.
Acknowledgements
Perl 5.23.1 represents approximately 4 weeks of development since Perl
5.23.0 and contains approximately 8,400 lines of changes across 320
files from 22 authors.
Excluding auto-generated files, documentation and release tools, there
were approximately 5,000 lines of changes to 140 .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 5.23.1:
Aaron Crane, Aristotle Pagaltzis, Chas. Owens, Chris 'BinGOs' Williams,
Craig A. Berry, Daniel Dragan, David Mitchell, Father Chrysostomos,
Herbert Breunung, H.Merijn Brand, James E Keenan, Jarkko Hietaniemi,
Karen Etheridge, Karl Williamson, Leon Timmermans, Matthew Horsfall,
Max Maischein, Rafael Garcia-Suarez, Ricardo Signes, Stanislaw Pusep,
Steve Hay, 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 <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.
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 v5.23.3 2015-09-08 PERL5231DELTA(1)
