perldelta - what is new for perl v5.8.7


This document describes differences between the 5.8.6 release and the 5.8.7 release.

Incompatible Changes

There are no changes incompatible with 5.8.6.

Core Enhancements

Unicode Character Database 4.1.0

The copy of the Unicode Character Database included in Perl 5.8 has been updated to 4.1.0 from 4.0.1. See for the notable changes.

suidperl less insecure

A pair of exploits in suidperl involving debugging code have been closed.

For new projects the core perl team strongly recommends that you use dedicated, single purpose security tools such as sudo in preference to suidperl.

Optional site customization script

The perl interpreter can be built to allow the use of a site customization script. By default this is not enabled, to be consistent with previous perl releases. To use this, add -Dusesitecustomize to the command line flags when running the Configure script. See also -f in the perlrun manpage. is now much smaller. is now about 3K rather than 32K, with the infrequently used code and %Config values loaded on demand. This is transparent to the programmer, but means that most code will save parsing and loading 29K of script (for example, code that uses File::Find).

Modules and Pragmata

Utility Changes

find2perl enhancements

find2perl has new options -iname, -path and -ipath.

Performance Enhancements

The internal pointer mapping hash used during ithreads cloning now uses an arena for memory allocation. In tests this reduced ithreads cloning time by about 10%.

Installation and Configuration Improvements

Selected Bug Fixes

New or Changed Diagnostics

There is a new taint error, ``%ENV is aliased to %s''. This error is thrown when taint checks are enabled and when *ENV has been aliased, so that %ENV has no env-magic anymore and hence the environment cannot be verified as taint-free.

The internals of pack and unpack have been updated. All legitimate templates should work as before, but there may be some changes in the error reported for complex failure cases. Any behaviour changes for non-error cases are bugs, and should be reported.

Changed Internals

There has been a fair amount of refactoring of the C source code, partly to make it tidier and more maintainable. The resulting object code and the perl binary may well be smaller than 5.8.6, and hopefully faster in some cases, but apart from this there should be no user-detectable changes.

${^UTF8LOCALE} has been added to give perl space access to PL_utf8locale.

The size of the arenas used to allocate SV heads and most SV bodies can now be changed at compile time. The old size was 1008 bytes, the new default size is 4080 bytes.

Known Problems

Unicode strings returned from overloaded operators can be buggy. This is a long standing bug reported since 5.8.6 was released, but we do not yet have a suitable fix for it.

Platform Specific Problems

On UNICOS, lib/Math/BigInt/t/bigintc.t hangs burning CPU. ext/B/t/bytecode.t and ext/Socket/t/socketpair.t both fail tests. These are unlikely to be resolved, as our valiant UNICOS porter's last Cray is being decommissioned.

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 There may also be information at, 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 to be analysed by the Perl porting team. You can browse and search the Perl 5 bugs at


The Changes file for 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.