version 0.9917

Object oriented versions for all Perl releases from 5.6.2 onward.  Replaces
the core version code for all Perl releases from 5.10.0 onwards.

Although this code has been fully integrated into the latest Perl release
itself (e.g. bleadperl), the CPAN release is considered upstream.  The source
code itself is available from two mirrors: (primary) (secondary)

and a bug queue here:

Patches welcomed.

IMPORTANT NOTE - 0.9906 is the last release that fully supports Perl
releases prior to 5.6.2.  It is just too much trouble to continue to
fight to maintain full backward compatibility.

There was a bug caused by objects serialized by YAML that will cause Perl
5.10.0 to segfault.  As long as some module calls 'use version', then the
replacement code will take effect and Perl will not crash.

Major Changes in 0.9917 - 2016-05-29
Fix version::regex captures, resolves:

Major Changes in 0.9916 - 2016-03-18
Incorporate changes from bleadperl (destined to be 5.24.0)

Major Changes in 0.9915 - 2016-03-05
Clarify details of Lyon Compromise:

- version comparision should be done irrespective of the presence of
  underscores in the string used to initialize the version object

- underscore should no longer be used as a tuple separator in vstrings or
  vstring-like strings; vstrings are converted to tuples by splitting into
  *characters* (not bytes) and converting to codepoints; any elements after
  the first must be in the range 0-999

- numify/normal should produce a standarized string representation without

- stringify should produce the best possible representation of the value
  used to initialize the version object; it should include underscores
  only if the initializing value was a non-vstring string.

- floating point numbers used as initializers are converted to a decimal
  string form at the precision limit of the architecture; people will be
  warned about this in the documentation

Major Changes in 0.9914 - 2016-02-18
Release non-alpha version to CPAN

Major Changes in 0.9913_01 - 2016-02-17
Apply one additional changeset from leont to handle magic v-strings

Major Changes in 0.9913 - 2016-02-16
Release non-alpha version to CPAN

Major Changes in 0.9912_03 - 2016-01-21
Apply two pull requests from bitbucket:

Major Changes in 0.9912_02 - 2016-01-03

Fix stupid mistake in locale tests, resolves:

Major Changes in 0.9912_01 - 2015-12-31

Apply patch to implement Lyon Consensus:

Also resolve the following tickets:

Major Changes in 0.9912 - 2015-01-20

Complete reverting the ill-conceived alpha->normal() code, resolves:

Skip leading zeros when parsing dotted-decimal versions after the
first element, resolves:

Minor change to report the correct URL, resolves:

Major Change in 0.9911 - 2015-01-17
Backout change to normal() and numify() because it breaks Module::Build

Major Changes in 0.9910 - 2015-01-17
Ensure that calling either normal() or numify() on an alpha version
is explicitly a lossy operation, and add a warning to that effect.  Forbid
trailing bare decimal for dotted-decimal versions.  Change heuristic in vpp
to better resolve v-string versions.  Various cleanups.


Patch from Dave Mitchell to rewrite the parser and avoid warnings
from clang.  Resolves

Major Changes in 0.9909 - 2014-08-15
Compatibility release for Perl 5.20.1.  Apply two patches from bleadperl
(one which shipped with 5.20.0 and one from bleadperl) so that a clean
release can be applied prior to 5.20.1 being shipped.  Holding back a few
other improvements, so expect 0.9910 shortly.

Major Changes in 0.9908 - 2014-02-02
More optimizations courtesy of Daniel Dragan (
Also resolves:

Major Changes in 0.9907 - 2014-01-12
Lots of optimizations of XS and C code courtesy of Daniel Dragan
(  Lots of minor tweaks as well.


Major Changes in 0.9906 - 2014-01-04
Applied C89 compatibility fix from Karl Williamson to  Added back
support for $version::LAX and $version::STRICT to resolve:

Major Changes in 0.9905 - 2014-01-04
Major rewrite of XS code to permit easier inclusion in core Perl (mostly 
written by Father Chrysostomos <>).  XS code is no longer
supported for any Perl < v5.10, although the pure Perl code still works
going back to 5.005_04.

In addition, the version::vpp class is now completely independent and can
be use'd exactly like the base version class.  It is still better to use
the base class for compatibility purposes.

Major Changes in 0.9904 - 2013-08-20
Final upstream changes from bleadperl.  Resolves RT tickets:

Major Changes in 0.9903 - 2013-08-18
Upstream test changes from bleadperl.
Include version::vpp even when installing XS version.
Subtle locale test changes.

Major Changes in 0.9902 - 2013-03-05
Upstream test changess from bleadperl.
Support env PERL_ONLY=1 as well as --perl-only.
version::new with no arguments reads past the end of the stack.

Major Changes in 0.9901 - 2012-04-26
Fix problem with short floating point alpha versions (e.g. 0.52_0).

Major Changes in 0.99 - 2012-04-26
Apply missing patch from core Perl to prevent overflow with ludicrous

Major Changes in 0.98 - 2012-04-25
Apply patch from core Perl to prevent overflow with ludicrous versions.

Major Changes in 0.97 - 2012-02-28
Minor tweak to locale test to skip if no locales are installed at all.

Major Changes in 0.96 - 2012-02-06
Merge in upstream changes from bleadperl.  Improved locale tests.

Major Changes in 0.95 - 2011-11-12
Restore compatibility in replacement UNIVERSAL::VERSION with the behavior
of Perl 5.14.x, essentially by reverting the changes in

Fix segfault error with strings that begin with 'v', especially the string
'version'.  Resolves:

Forbid all math operations on version objects in base class (this was
already the case for XS code but the pure Perl was lacking).  Resolves:

Major Changes in 0.94 - 2011-08-21
Clarify documentation on advisability of using leading 'v' (it isn't
mandatory, but it is much more likely to DTRT).  Resolves:

Use a localized DIE handler when attempting to load the XS code, in case
the caller has its own DIE handler.  Resolves:

Major Changes in 0.93 - 2011-07-27
Fix problem with UNIVERSAL::VERSION noted by Father Chrysostomos.

Major Changes in 0.92 - 2011-07-26
Forbid negative versions.  Make replacement UNIVERSAL::VERSION return the
original $VERSION scalar if called without a requested version.  Resolves

Rewrite code so that we just override all subs for Perl >= 5.9.0 (when was added to the core).

Major Changes in 0.91 - 2011-06-05
Fix compilation/linking on Strawberry Perl, resolves

Major Changes in 0.90 - 2011-06-01
Make all tests pass even with older Test::More releases.  Resolves

Major Changes in 0.89 - 2011-05-31
Change behavior of pure Perl qv/declare to match the core/XS behavior; do 
not use parent's new() class for derived classes.  This breaks
encapsulation but I can justify it because qv/declare is a very specific
thing that shouldn't be casually overridden (unless you do it directly in the

Major Changes in 0.88 - 2010-12-19
Fix Makefile.PL to make Strawberry Perl happy.  Resolves:

Major Changes in 0.87 - 2010-12-09
Remove Build.PL since there are modules in the Module::Build tool chain
that require, leading to circular dependencies.  This also allows
Module::Build itself to depend on

Major Changes in 0.86 - 2010-11-26
is_strict/is_lax were not exported correctly (which no one noticed).  Also
pull in strict/lax tests from core.

Major Changes in 0.85 - 2010-10-25
Don't include MYMETA.yml file in distro

Major Changes in 0.84 - 2010-10-24
Restore public API vcmp() broken in 0.83

Major Changes in 0.83 - 2010-10-17
Changed vverify API (David Golden).  Improved heuristic for non-magical
v-strings (Perl 5.6.0-5.8.0).  Install in proper patch post-@INC

Major Changes in 0.82 - 2010-04-13
Still more changes to sync with Perl 5.12.0-as-released.  Rewritten POD
thanks to many hands, but mostly David Golden.  Vastly improved Regex
definitions from Zephram.

Major Changes in 0.81 - 2010-02-01
Merge in changes from bleadperl that will be part of Perl 5.12.0.
Completely rewrite pure Perl code to operate exactly like the XS code,
through the creation of a character-array class called charstar.  Now
the pure Perl code and XS code can be more easily be synchronized.

Major Changes in 0.80 - 2010-01-21
No outwardly visible changes.  This release is to fix an assertion error
with certain picky/older compilers.  NOTE: this is not the version object
code that will be part of Perl 5.12.0, which will be released shortly as

Major Changes in 0.79 - 2010-01-03
No outwardly visible changes.  This release is to match the code that 
will part of Perl 5.12.0, but which doesn't affect the external API of
the CPAN release.

Major Changes in 0.78 - 2009-10-12
More changes to improve the non-magic v-string heuristics, this time 
affecting both the pure Perl and XS backends.  NOTE: these fixes only
matter if you are running Perl 5.6.x to 5.8.0 (inclusive).  Beginning
with Perl 5.8.1, v-strings are now magical and no longer has
to guess.  Resolves:

Also resolve the issue where attempting to install CPAN releases on top
of core releases (e.g. 5.10.0 and 5.10.1) would not DTRT.  Resolves:

Major Changes in 0.7702 - 2009-09-07
Add additional contraints to the code which tries to guess whether something
is a v-string or not for Perl 5.6.0 through 5.8.0 (inclusive).  Resolves:

Major Changes in 0.7701 - 2009-07-28
Special RHEL4.x/Fedora4.x Are Too Stupid to Live Release.  Those distros
have never updated beyond Perl 5.8.5/5.8.6 respectively.  Consequently,
they contain a complete broken Test::More::use_ok which doesn't load the
package into the correct namespace:

thus causing mysterious test failures.  No code was changed at
all. :(

Major Changes in 0.77 - 2009-07-26

Complete POD rewrite to document common usage in version.pod and put all
of the implementation details into version::Internals.

Resolve a number of RT tickets:
RT#48135 - Compilation failure using MS VC++ 7.0.
RT#47980 - Remove need for runtime class loading in pure Perl code
RT#46921 - locale and eval action at a distance.
RT#45241 - mistaken regex to convert large exponential numbers
to non-exponential form before scanning.

Please read the POD documentation for usage/details.  See the CHANGES file
for full details of all changes to the module behavior.


To install this module type the following:

   $ perl Makefile.PL
   $ make
   $ make test
   # make install

This release includes an optional pure Perl implementation (in case
you don't have a C-compiler or if some reason you want your code to be
much slower).  You can test it by replacing the first line above with:

   $ perl Makefile.PL --perl_only

and it will install the Perl only version.


The same C compiler used to build Perl (or not).


This module can be distributed under the same terms as Perl.

Copyright (C) 2004-2015 John Peacock