=encoding utf8

=head1 NAME

perldelta - what is new for perl v5.24.1

=head1 DESCRIPTION

This document describes differences between the 5.24.0 release and the 5.24.1
release.

If you are upgrading from an earlier release such as 5.23.0, first read
L<perl5240delta>, which describes differences between 5.23.0 and 5.24.0.

=head1 Security

=head2 B<-Di> switch is now required for PerlIO debugging output

Previously PerlIO debugging output would be sent to the file specified by the
C<PERLIO_DEBUG> environment variable if perl wasn't running setuid and the
B<-T> or B<-t> switches hadn't been parsed yet.

If perl performed output at a point where it hadn't yet parsed its switches
this could result in perl creating or overwriting the file named by
C<PERLIO_DEBUG> even when the B<-T> switch had been supplied.

Perl now requires the B<-Di> switch to produce PerlIO debugging output.  By
default this is written to C<stderr>, but can optionally be redirected to a
file by setting the C<PERLIO_DEBUG> environment variable.

If perl is running setuid or the B<-T> switch was supplied C<PERLIO_DEBUG> is
ignored and the debugging output is sent to C<stderr> as for any other B<-D>
switch.

=head1 Incompatible Changes

There are no changes intentionally incompatible with Perl 5.24.0.  If any
exist, they are bugs, and we request that you submit a report.  See
L</Reporting Bugs> below.

=head1 Modules and Pragmata

=head2 Updated Modules and Pragmata

=over 4

=item *

L<Module::CoreList> has been upgraded from version 5.20160506 to 5.20160730_24.

=back

=head1 Documentation

=head2 Changes to Existing Documentation

=head3 L<perlapio>

=over 4

=item *

The documentation of C<PERLIO_DEBUG> has been updated.

=back

=head3 L<perlrun>

=over 4

=item *

The new B<-Di> switch has been documented, and the documentation of
C<PERLIO_DEBUG> has been updated.

=back

=head1 Testing

=over 4

=item *

A new test script, F<t/run/switchDx.t>, has been added to test that the new
B<-Di> switch is working correctly.

=back

=head1 Selected Bug Fixes

=over 4

=item *

The change to hashbang redirection introduced in Perl 5.24.0, whereby perl
would redirect to another interpreter (Perl 6) if it found a hashbang path
which contains "perl" followed by "6", has been reverted because it broke in
cases such as C<#!/opt/perl64/bin/perl>.

=back

=head1 Acknowledgements

Perl 5.24.1 represents approximately 2 months of development since Perl 5.24.0
and contains approximately 5,700 lines of changes across 46 files from 11
authors.

Excluding auto-generated files, documentation and release tools, there were
approximately 590 lines of changes to 11 .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 5.24.1:

Alex Vandiver, Craig A. Berry, Father Chrysostomos, James E Keenan, Karen
Etheridge, Leon Timmermans, Matthew Horsfall, Ricardo Signes, Sawyer X, 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 F<AUTHORS> file in the Perl source distribution.

=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
L<https://rt.perl.org/> .  There may also be information at
L<http://www.perl.org/> , the Perl Home Page.

If you believe you have an unreported bug, please run the L<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.

If the bug you are reporting has security implications which make it
inappropriate to send to a publicly archived mailing list, then see
L<perlsec/SECURITY VULNERABILITY CONTACT INFORMATION> for details of how to
report the issue.

=head1 SEE ALSO

The F<Changes> file for an explanation of how to view 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.

=cut
