[p5sagit/p5-mst-13.2.git] / pod / perl571delta.pod

=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
Commit	Line	Data
d468ca04	1	=head1 NAME
	2
	3	perl571delta - what's new for perl v5.7.1
	4
	5	=head1 DESCRIPTION
	6
	7	This document describes differences between the 5.7.0 release and the
	8	5.7.1 release.
	9
	10	(To view the differences between the 5.6.0 release and the 5.7.0
	11	release, see L<perl570delta>).
	12
	13	=head1 Incompatible Changes
	14
	15	=over 4
	16
	17	=item *
	18
	19	Although "you shouldn't do that", it was possible to write code that
	20	depends on Perl's hashed key order (Data::Dumper does this). The new
	21	algorithm "One-at-a-Time" produces a different hashed key order.
	22	More details are in L<perldelta/Performance Enhancements>.
	23
	24	=back
	25
	26	=head1 Core Enhancements
	27
	28	=over 4
	29
	30	=item *
	31
	32	Formats now support zero-padded decimal fields.
	33
	34	=item *
	35
	36	The printf and sprintf now support parameter reordering using the
	37	C<%\d+\$> and C<*\d+\$> syntaxes.
	38
	39	=back
	40
	41	=head1 Performance Enhancements
	42
	43	=over 4
	44
	45	=item *
	46
	47	Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm
	48	(http://burtleburtle.net/bob/hash/doobs.html).
	49	This algorithm is reasonably fast while producing a much better spread
	50	of values. Hash values output from the algorithm on a hash of all
	51	3-char printable ASCII keys comes much closer to passing the DIEHARD
	52	random number generation tests. According to perlbench, this change
	53	has not affected the overall speed of Perl.
	54
	55	=back
	56
	57	=head1 Installation and Configuration Improvements
	58
	59	=over 4
	60
	61	=item *
	62
	63	Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm)
	64	when building the Perl binary. The only exception to this is SunOS 4.x,
65	which needs them.
66
67	=back
68
69	=head1 Selected Bug Fixes
70
71	=over 4
72
73	=item *
74
75	vec() now tries to work with characters <= 255 when possible, but it leaves
76	higher character values in place. In that case, if vec() was used to modify
77	the string, it is no longer considered to be utf8-encoded.
78
79	=back
80
81	=head1 Known Problems
82
83	=head2 sprintf tests 129 and 130
84
85	The op/sprintf tests 129 and 130 are known to fail in some platforms.
86	Examples include any platform using sfio, and Tandem's NonStop-UX.
87	The failing platforms do not comply with the ANSI C Standard, line
88	19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce
89	something else than "1" and "-1" when formatting 0.6 and -0.6 using
90	the printf format "%.0f", most often they produce "0" and "-0".)
91
92	=head1 Reporting Bugs
93
94	If you find what you think is a bug, you might check the articles
95	recently posted to the comp.lang.perl.misc newsgroup and the perl
96	bug database at http://bugs.perl.org. There may also be
97	information at http://www.perl.com/perl/, the Perl Home Page.
98
99	If you believe you have an unreported bug, please run the B<perlbug>
100	program included with your release. Be sure to trim your bug down
101	to a tiny but sufficient test case. Your bug report, along with the
102	output of C<perl -V>, will be sent off to perlbug@perl.org to be
103	analysed by the Perl porting team.
104
105	=head1 SEE ALSO
106
107	The F<Changes> file for exhaustive details on what changed.
108
109	The F<INSTALL> file for how to build Perl.
110
111	The F<README> file for general stuff.
112
113	The F<Artistic> and F<Copying> files for copyright information.
114
115	=head1 HISTORY
116
117	Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions
118	from The Perl Porters and Perl Users submitting feedback and patches.
119
120	Send omissions or corrections to <F<perlbug@perl.org>>.
121
122	=cut