=head1 NAME

perl571delta - what's new for perl v5.7.1

=head1 DESCRIPTION

This document describes differences between the 5.7.0 release and the
5.7.1 release.  

(To view the differences between the 5.6.0 release and the 5.7.0
release, see L<perl570delta>).

=head1 Incompatible Changes

=over 4

=item *

Although "you shouldn't do that", it was possible to write code that
depends on Perl's hashed key order (Data::Dumper does this).  The new
algorithm "One-at-a-Time" produces a different hashed key order.
More details are in L<perldelta/Performance Enhancements>.

=back

=head1 Core Enhancements

=over 4

=item *

Formats now support zero-padded decimal fields.

=item *
 
The printf and sprintf now support parameter reordering using the
C<%\d+\$> and C<*\d+\$> syntaxes.

=back

=head1 Performance Enhancements

=over 4

=item *

Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
(http://burtleburtle.net/bob/hash/doobs.html).
This algorithm is reasonably fast while producing a much better spread
of values.  Hash values output from the algorithm on a hash of all
3-char printable ASCII keys comes much closer to passing the DIEHARD
random number generation tests.  According to perlbench, this change
has not affected the overall speed of Perl.

=back

=head1 Installation and Configuration Improvements

=over 4

=item *

Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
when building the Perl binary. The only exception to this is SunOS 4.x,
which needs them.

=back

=head1 Selected Bug Fixes

=over 4

=item *

vec() now tries to work with characters <= 255 when possible, but it leaves
higher character values in place.  In that case, if vec() was used to modify
the string, it is no longer considered to be utf8-encoded.

=back

=head1 Known Problems

=head2 sprintf tests 129 and 130

The op/sprintf tests 129 and 130 are known to fail in some platforms.
Examples include any platform using sfio, and Tandem's NonStop-UX.
The failing platforms do not comply with the ANSI C Standard, line
19ff on page 134 of ANSI X3.159 1989 to be exact.  (They produce
something else than "1" and "-1" when formatting 0.6 and -0.6 using
the printf format "%.0f", most often they produce "0" and "-0".)

=head1 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://bugs.perl.org.  There may also be
information at http://www.perl.com/perl/, the Perl Home Page.

If you believe you have an unreported bug, please run the B<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 C<perl -V>, will be sent off to perlbug@perl.org to be
analysed by the Perl porting team.

=head1 SEE ALSO

The F<Changes> file for exhaustive details on what changed.

The F<INSTALL> file for how to build Perl.

The F<README> file for general stuff.

The F<Artistic> and F<Copying> files for copyright information.

=head1 HISTORY

Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions
from The Perl Porters and Perl Users submitting feedback and patches.

Send omissions or corrections to <F<perlbug@perl.org>>.

=cut