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            <h1>perl5101delta</h1>


  <!--    -->
<ul><li><a href="#NAME">NAME</a><li><a href="#DESCRIPTION">DESCRIPTION</a><li><a href="#Incompatible-Changes">Incompatible Changes</a><ul><li><a href="#Switch-statement-changes">Switch statement changes</a><li><a href="#Smart-match-changes">Smart match changes</a><li><a href="#Other-incompatible-changes">Other incompatible changes</a></ul><li><a href="#Core-Enhancements">Core Enhancements</a><ul><li><a href="#Unicode-Character-Database-5.1.0">Unicode Character Database 5.1.0</a><li><a href="#A-proper-interface-for-pluggable-Method-Resolution-Orders">A proper interface for pluggable Method Resolution Orders</a><li><a href="#The-overloading-pragma">The overloading pragma</a><li><a href="#Parallel-tests">Parallel tests</a><li><a href="#DTrace-support">DTrace support</a><li><a href="#Support-for-configure_requires-in-CPAN-module-metadata">Support for configure_requires in CPAN module metadata</a></ul><li><a href="#Modules-and-Pragmata">Modules and Pragmata</a><ul><li><a href="#New-Modules-and-Pragmata">New Modules and Pragmata</a><li><a href="#Pragmata-Changes">Pragmata Changes</a><li><a href="#Updated-Modules">Updated Modules</a></ul><li><a href="#Utility-Changes">Utility Changes</a><li><a href="#New-Documentation">New Documentation</a><li><a href="#Changes-to-Existing-Documentation">Changes to Existing Documentation</a><li><a href="#Performance-Enhancements">Performance Enhancements</a><li><a href="#Installation-and-Configuration-Improvements">Installation and Configuration Improvements</a><ul><li><a href="#_ext%2f_-reorganisation">_ext/_ reorganisation</a><li><a href="#Configuration-improvements">Configuration improvements</a><li><a href="#Compilation-improvements">Compilation improvements</a><li><a href="#Platform-Specific-Changes">Platform Specific Changes</a></ul><li><a href="#Selected-Bug-Fixes">Selected Bug Fixes</a><li><a href="#New-or-Changed-Diagnostics">New or Changed Diagnostics</a><li><a href="#Changed-Internals">Changed Internals</a><li><a href="#New-Tests">New Tests</a><li><a href="#Known-Problems">Known Problems</a><li><a href="#Deprecations">Deprecations</a><li><a href="#Acknowledgements">Acknowledgements</a><li><a href="#Reporting-Bugs">Reporting Bugs</a><li><a href="#SEE-ALSO">SEE ALSO</a></ul><a name="NAME"></a><h1>NAME</h1>
<p>perl5101delta - what is new for perl v5.10.1</p>
<a name="DESCRIPTION"></a><h1>DESCRIPTION</h1>
<p>This document describes differences between the 5.10.0 release and
the 5.10.1 release.</p>
<p>If you are upgrading from an earlier release such as 5.8.8, first read
the <a href="perl5100delta.html">perl5100delta</a>, which describes differences between 5.8.8 and
5.10.0</p>
<a name="Incompatible-Changes"></a><h1>Incompatible Changes</h1>
<a name="Switch-statement-changes"></a><h2>Switch statement changes</h2>
<p>The handling of complex expressions by the <code class="inline">given</code>
/<code class="inline">when</code>
 switch
statement has been enhanced. There are two new cases where <code class="inline">when</code>
 now
interprets its argument as a boolean, instead of an expression to be used
in a smart match:</p>
<ul>
<li><a name="flip-flop-operators"></a><b>flip-flop operators</b>
<p>The <code class="inline">..</code>
 and <code class="inline">...</code>
 flip-flop operators are now evaluated in boolean
context, following their usual semantics; see <a href="perlop.html#Range-Operators">Range Operators in perlop</a>.</p>
<p>Note that, as in perl 5.10.0, <code class="inline">when <span class="s">(</span><span class="n">1</span>..<span class="n">10</span><span class="s">)</span></code>
 will not work to test
whether a given value is an integer between 1 and 10; you should use
<code class="inline">when <span class="s">(</span><span class="s">[</span><span class="n">1</span>..<span class="n">10</span><span class="s">]</span><span class="s">)</span></code>
 instead (note the array reference).</p>
<p>However, contrary to 5.10.0, evaluating the flip-flop operators in boolean
context ensures it can now be useful in a <code class="inline">when<span class="s">(</span><span class="s">)</span></code>
, notably for
implementing bistable conditions, like in:</p>
<pre class="verbatim"><ol><li>    when <span class="s">(</span><span class="q">/^=begin/</span> .. <span class="q">/^=end/</span><span class="s">)</span> <span class="s">{</span></li><li>      <span class="c"># do something</span></li><li>    <span class="s">}</span></li></ol></pre></li>
<li><a name="defined-or-operator"></a><b>defined-or operator</b>
<p>A compound expression involving the defined-or operator, as in
<code class="inline">when (expr1 // expr2)</code>, will be treated as boolean if the first
expression is boolean. (This just extends the existing rule that applies
to the regular or operator, as in <code class="inline">when <span class="s">(</span><span class="w">expr1</span> || <span class="w">expr2</span><span class="s">)</span></code>
.)</p>
</li>
</ul>
<p>The next section details more changes brought to the semantics to
the smart match operator, that naturally also modify the behaviour
of the switch statements where smart matching is implicitly used.</p>
<a name="Smart-match-changes"></a><h2>Smart match changes</h2>
<a name="Changes-to-type-based-dispatch"></a><h3>Changes to type-based dispatch</h3>
<p>The smart match operator <code class="inline">~~</code>
 is no longer commutative. The behaviour of
a smart match now depends primarily on the type of its right hand
argument. Moreover, its semantics have been adjusted for greater
consistency or usefulness in several cases. While the general backwards
compatibility is maintained, several changes must be noted:</p>
<ul>
<li>
<p>Code references with an empty prototype are no longer treated specially.
They are passed an argument like the other code references (even if they
choose to ignore it).</p>
</li>
<li>
<p><code class="inline"><span class="i">%hash</span> ~~ <a class="l_k" href="functions/sub.html">sub</a> <span class="s">{</span><span class="s">}</span></code>
 and <code class="inline"><span class="i">@array</span> ~~ <a class="l_k" href="functions/sub.html">sub</a> <span class="s">{</span><span class="s">}</span></code>
 now test that the subroutine
returns a true value for each key of the hash (or element of the
array), instead of passing the whole hash or array as a reference to
the subroutine.</p>
</li>
<li>
<p>Due to the commutativity breakage, code references are no longer
treated specially when appearing on the left of the <code class="inline">~~</code>
 operator,
but like any vulgar scalar.</p>
</li>
<li>
<p><code class="inline"><a class="l_k" href="functions/undef.html">undef</a> ~~ <span class="i">%hash</span></code>
 is always false (since <code class="inline"><a class="l_k" href="functions/undef.html">undef</a></code> can't be a key in a
hash). No implicit conversion to <code class="inline"><span class="q">&quot;&quot;</span></code>
 is done (as was the case in perl
5.10.0).</p>
</li>
<li>
<p><code class="inline"><span class="i">$scalar</span> ~~ <span class="i">@array</span></code>
 now always distributes the smart match across the
elements of the array. It's true if one element in @array verifies
<code class="inline"><span class="i">$scalar</span> ~~ <span class="i">$element</span></code>
. This is a generalization of the old behaviour
that tested whether the array contained the scalar.</p>
</li>
</ul>
<p>The full dispatch table for the smart match operator is given in
<a href="perlsyn.html#Smart-matching-in-detail">Smart matching in detail in perlsyn</a>.</p>
<a name="Smart-match-and-overloading"></a><h3>Smart match and overloading</h3>
<p>According to the rule of dispatch based on the rightmost argument type,
when an object overloading <code class="inline">~~</code>
 appears on the right side of the
operator, the overload routine will always be called (with a 3rd argument
set to a true value, see <a href="overload.html">overload</a>.) However, when the object will
appear on the left, the overload routine will be called only when the
rightmost argument is a simple scalar. This way distributivity of smart match
across arrays is not broken, as well as the other behaviours with complex
types (coderefs, hashes, regexes). Thus, writers of overloading routines
for smart match mostly need to worry only with comparing against a scalar,
and possibly with stringification overloading; the other common cases
will be automatically handled consistently.</p>
<p><code class="inline">~~</code>
 will now refuse to work on objects that do not overload it (in order
to avoid relying on the object's underlying structure). (However, if the
object overloads the stringification or the numification operators, and
if overload fallback is active, it will be used instead, as usual.)</p>
<a name="Other-incompatible-changes"></a><h2>Other incompatible changes</h2>
<ul>
<li>
<p>The semantics of <code class="inline">use feature :5.10*</code> have changed slightly.
See <a href="#Modules-and-Pragmata">Modules and Pragmata</a> for more information.</p>
</li>
<li>
<p>It is now a run-time error to use the smart match operator <code class="inline">~~</code>

with an object that has no overload defined for it. (This way
<code class="inline">~~</code>
 will not break encapsulation by matching against the
object's internal representation as a reference.)</p>
</li>
<li>
<p>The version control system used for the development of the perl
interpreter has been switched from Perforce to git.  This is mainly an
internal issue that only affects people actively working on the perl core;
but it may have minor external visibility, for example in some of details
of the output of <code class="inline"><span class="w">perl</span> -<span class="w">V</span></code>
. See <a href="perlrepository.html">perlrepository</a> for more information.</p>
</li>
<li>
<p>The internal structure of the <code class="inline"><span class="w">ext</span>/</code>
 directory in the perl source has
been reorganised. In general, a module <code class="inline"><span class="w">Foo::Bar</span></code>
 whose source was
stored under <i>ext/Foo/Bar/</i> is now located under <i>ext/Foo-Bar/</i>. Also,
some modules have been moved from <i>lib/</i> to <i>ext/</i>. This is purely a
source tarball change, and should make no difference to the compilation or
installation of perl, unless you have a very customised build process that
explicitly relies on this structure, or which hard-codes the <code class="inline"><span class="w">nonxs_ext</span></code>

<i>Configure</i> parameter. Specifically, this change does not by default
alter the location of any files in the final installation.</p>
</li>
<li>
<p>As part of the <code class="inline"><span class="w">Test::Harness</span></code>
 2.x to 3.x upgrade, the experimental
<code class="inline"><span class="w">Test::Harness::Straps</span></code>
 module has been removed.
See <a href="#Updated-Modules">Updated Modules</a> for more details.</p>
</li>
<li>
<p>As part of the <code class="inline"><span class="w">ExtUtils::MakeMaker</span></code>
 upgrade, the
<code class="inline"><span class="w">ExtUtils::MakeMaker::bytes</span></code>
 and <code class="inline"><span class="w">ExtUtils::MakeMaker::vmsish</span></code>
 modules
have been removed from this distribution.</p>
</li>
<li>
<p><code class="inline"><span class="w">Module::CoreList</span></code>
 no longer contains the <code class="inline">%:patchlevel</code> hash.</p>
</li>
<li>
<p>This one is actually a change introduced in 5.10.0, but it was missed
from that release's perldelta, so it is mentioned here instead.</p>
<p>A bugfix related to the handling of the <code class="inline">/m</code> modifier and <code class="inline"><a class="l_k" href="functions/qr.html">qr</a></code> resulted
in a change of behaviour between 5.8.x and 5.10.0:</p>
<pre class="verbatim"><ol><li>    <span class="c"># matches in 5.8.x, doesn&#39;t match in 5.10.0</span></li><li>    <span class="i">$re</span> = <span class="q">qr/^bar/</span><span class="sc">;</span> <span class="q">&quot;foo\nbar&quot;</span> =~ <span class="q">/$re/m</span><span class="sc">;</span></li></ol></pre></li>
</ul>
<a name="Core-Enhancements"></a><h1>Core Enhancements</h1>
<a name="Unicode-Character-Database-5.1.0"></a><h2>Unicode Character Database 5.1.0</h2>
<p>The copy of the Unicode Character Database included in Perl 5.10.1 has
been updated to 5.1.0 from 5.0.0. See
<a href="http://www.unicode.org/versions/Unicode5.1.0/#Notable_Changes">http://www.unicode.org/versions/Unicode5.1.0/#Notable_Changes</a> for the
notable changes.</p>
<a name="A-proper-interface-for-pluggable-Method-Resolution-Orders"></a><h2>A proper interface for pluggable Method Resolution Orders</h2>
<p>As of Perl 5.10.1 there is a new interface for plugging and using method
resolution orders other than the default (linear depth first search).
The C3 method resolution order added in 5.10.0 has been re-implemented as
a plugin, without changing its Perl-space interface. See <a href="perlmroapi.html">perlmroapi</a> for
more information.</p>
<a name="The-overloading-pragma"></a><h2>The <code class="inline"><span class="w">overloading</span></code>
 pragma</h2>
<p>This pragma allows you to lexically disable or enable overloading
for some or all operations. (Yuval Kogman)</p>
<a name="Parallel-tests"></a><h2>Parallel tests</h2>
<p>The core distribution can now run its regression tests in parallel on
Unix-like platforms. Instead of running <code class="inline"><span class="w">make</span> <span class="w">test</span></code>
, set <code class="inline"><span class="w">TEST_JOBS</span></code>
 in
your environment to the number of tests to run in parallel, and run
<code class="inline"><span class="w">make</span> <span class="w">test_harness</span></code>
. On a Bourne-like shell, this can be done as</p>
<pre class="verbatim"><ol><li>    TEST_JOBS=3 make test_harness  # Run 3 tests in parallel</li></ol></pre><p>An environment variable is used, rather than parallel make itself, because
<a href="TAP/Harness.html">TAP::Harness</a> needs to be able to schedule individual non-conflicting test
scripts itself, and there is no standard interface to <code class="inline"><span class="w">make</span></code>
 utilities to
interact with their job schedulers.</p>
<p>Note that currently some test scripts may fail when run in parallel (most
notably <code class="inline"><span class="w">ext</span>/<span class="w">IO</span>/<span class="w">t</span>/<span class="w">io_dir</span>.<span class="w">t</span></code>
). If necessary run just the failing scripts
again sequentially and see if the failures go away.</p>
<a name="DTrace-support"></a><h2>DTrace support</h2>
<p>Some support for DTrace has been added. See "DTrace support" in <i>INSTALL</i>.</p>
<a name="Support-for-configure_requires-in-CPAN-module-metadata"></a><h2>Support for <code class="inline"><span class="w">configure_requires</span></code>
 in CPAN module metadata</h2>
<p>Both <code class="inline"><span class="w">CPAN</span></code>
 and <code class="inline"><span class="w">CPANPLUS</span></code>
 now support the <code class="inline"><span class="w">configure_requires</span></code>
 keyword
in the <code class="inline"><span class="w">META</span>.<span class="w">yml</span></code>
 metadata file included in most recent CPAN distributions.
This allows distribution authors to specify configuration prerequisites that
must be installed before running <i>Makefile.PL</i> or <i>Build.PL</i>.</p>
<p>See the documentation for <code class="inline"><span class="w">ExtUtils::MakeMaker</span></code>
 or <code class="inline"><span class="w">Module::Build</span></code>
 for more
on how to specify <code class="inline"><span class="w">configure_requires</span></code>
 when creating a distribution for CPAN.</p>
<a name="Modules-and-Pragmata"></a><h1>Modules and Pragmata</h1>
<a name="New-Modules-and-Pragmata"></a><h2>New Modules and Pragmata</h2>
<ul>
<li><a name="autodie"></a><b><code class="inline"><span class="w">autodie</span></code>
</b>
<p>This is a new lexically-scoped alternative for the <code class="inline"><span class="w">Fatal</span></code>
 module.
The bundled version is 2.06_01. Note that in this release, using a string
eval when <code class="inline"><span class="w">autodie</span></code>
 is in effect can cause the autodie behaviour to leak
into the surrounding scope. See <a href="autodie.html#BUGS">BUGS in autodie</a> for more details.</p>
</li>
<li><a name="Compress%3a%3aRaw%3a%3aBzip2"></a><b><code class="inline"><span class="w">Compress::Raw::Bzip2</span></code>
</b>
<p>This has been added to the core (version 2.020).</p>
</li>
<li><a name="parent"></a><b><code class="inline"><span class="w">parent</span></code>
</b>
<p>This pragma establishes an ISA relationship with base classes at compile
time. It provides the key feature of <code class="inline"><span class="w">base</span></code>
 without the feature creep.</p>
</li>
<li><a name="Parse%3a%3aCPAN%3a%3aMeta"></a><b><code class="inline"><span class="w">Parse::CPAN::Meta</span></code>
</b>
<p>This has been added to the core (version 1.39).</p>
</li>
</ul>
<a name="Pragmata-Changes"></a><h2>Pragmata Changes</h2>
<ul>
<li><a name="attributes"></a><b><code class="inline"><span class="w">attributes</span></code>
</b>
<p>Upgraded from version 0.08 to 0.09.</p>
</li>
<li><a name="attrs"></a><b><code class="inline"><span class="w">attrs</span></code>
</b>
<p>Upgraded from version 1.02 to 1.03.</p>
</li>
<li><a name="base"></a><b><code class="inline"><span class="w">base</span></code>
</b>
<p>Upgraded from version 2.13 to 2.14. See <a href="parent.html">parent</a> for a replacement.</p>
</li>
<li><a name="bigint"></a><b><code class="inline"><span class="w">bigint</span></code>
</b>
<p>Upgraded from version 0.22 to 0.23.</p>
</li>
<li><a name="bignum"></a><b><code class="inline"><span class="w">bignum</span></code>
</b>
<p>Upgraded from version 0.22 to 0.23.</p>
</li>
<li><a name="bigrat"></a><b><code class="inline"><span class="w">bigrat</span></code>
</b>
<p>Upgraded from version 0.22 to 0.23.</p>
</li>
<li><a name="charnames"></a><b><code class="inline"><span class="w">charnames</span></code>
</b>
<p>Upgraded from version 1.06 to 1.07.</p>
<p>The Unicode <i>NameAliases.txt</i> database file has been added. This has the
effect of adding some extra <code class="inline">\<span class="w">N</span></code>
 character names that formerly wouldn't
have been recognised; for example, <code class="inline"><span class="q">&quot;\N{LATIN CAPITAL LETTER GHA}&quot;</span></code>
.</p>
</li>
<li><a name="constant"></a><b><code class="inline"><span class="w">constant</span></code>
</b>
<p>Upgraded from version 1.13 to 1.17.</p>
</li>
<li><a name="feature"></a><b><code class="inline"><span class="w">feature</span></code>
</b>
<p>The meaning of the <code class="inline"><span class="j">:</span><span class="n">5.10</span></code>
 and <code class="inline"><span class="j">:</span><span class="n">5.10</span>.<span class="w">X</span></code>
 feature bundles has
changed slightly. The last component, if any (i.e. <code class="inline"><span class="w">X</span></code>
) is simply ignored.
This is predicated on the assumption that new features will not, in
general, be added to maintenance releases. So <code class="inline"><span class="j">:</span><span class="n">5.10</span></code>
 and <code class="inline"><span class="j">:</span><span class="n">5.10</span>.<span class="w">X</span></code>

have identical effect. This is a change to the behaviour documented for
5.10.0.</p>
</li>
<li><a name="fields"></a><b><code class="inline"><span class="w">fields</span></code>
</b>
<p>Upgraded from version 2.13 to 2.14 (this was just a version bump; there
were no functional changes).</p>
</li>
<li><a name="lib"></a><b><code class="inline"><span class="w">lib</span></code>
</b>
<p>Upgraded from version 0.5565 to 0.62.</p>
</li>
<li><a name="open"></a><b><code class="inline"><a class="l_k" href="functions/open.html">open</a></code></b>
<p>Upgraded from version 1.06 to 1.07.</p>
</li>
<li><a name="overload"></a><b><code class="inline"><span class="w">overload</span></code>
</b>
<p>Upgraded from version 1.06 to 1.07.</p>
</li>
<li><a name="overloading"></a><b><code class="inline"><span class="w">overloading</span></code>
</b>
<p>See <a href="#The-overloading-pragma">The overloading pragma</a> above.</p>
</li>
<li><a name="version"></a><b><code class="inline"><span class="w">version</span></code>
</b>
<p>Upgraded from version 0.74 to 0.77.</p>
</li>
</ul>
<a name="Updated-Modules"></a><h2>Updated Modules</h2>
<ul>
<li><a name="Archive%3a%3aExtract"></a><b><code class="inline"><span class="w">Archive::Extract</span></code>
</b>
<p>Upgraded from version 0.24 to 0.34.</p>
</li>
<li><a name="Archive%3a%3aTar"></a><b><code class="inline"><span class="w">Archive::Tar</span></code>
</b>
<p>Upgraded from version 1.38 to 1.52.</p>
</li>
<li><a name="Attribute%3a%3aHandlers"></a><b><code class="inline"><span class="w">Attribute::Handlers</span></code>
</b>
<p>Upgraded from version 0.79 to 0.85.</p>
</li>
<li><a name="AutoLoader"></a><b><code class="inline"><span class="w">AutoLoader</span></code>
</b>
<p>Upgraded from version 5.63 to 5.68.</p>
</li>
<li><a name="AutoSplit"></a><b><code class="inline"><span class="w">AutoSplit</span></code>
</b>
<p>Upgraded from version 1.05 to 1.06.</p>
</li>
<li><a name="B"></a><b><code class="inline"><span class="w">B</span></code>
</b>
<p>Upgraded from version 1.17 to 1.22.</p>
</li>
<li><a name="B%3a%3aDebug"></a><b><code class="inline"><span class="w">B::Debug</span></code>
</b>
<p>Upgraded from version 1.05 to 1.11.</p>
</li>
<li><a name="B%3a%3aDeparse"></a><b><code class="inline"><span class="w">B::Deparse</span></code>
</b>
<p>Upgraded from version 0.83 to 0.89.</p>
</li>
<li><a name="B%3a%3aLint"></a><b><code class="inline"><span class="w">B::Lint</span></code>
</b>
<p>Upgraded from version 1.09 to 1.11.</p>
</li>
<li><a name="B%3a%3aXref"></a><b><code class="inline"><span class="w">B::Xref</span></code>
</b>
<p>Upgraded from version 1.01 to 1.02.</p>
</li>
<li><a name="Benchmark"></a><b><code class="inline"><span class="w">Benchmark</span></code>
</b>
<p>Upgraded from version 1.10 to 1.11.</p>
</li>
<li><a name="Carp"></a><b><code class="inline"><span class="w">Carp</span></code>
</b>
<p>Upgraded from version 1.08 to 1.11.</p>
</li>
<li><a name="CGI"></a><b><code class="inline"><span class="w">CGI</span></code>
</b>
<p>Upgraded from version 3.29 to 3.43.
(also includes the "default_value for popup_menu()" fix from 3.45).</p>
</li>
<li><a name="Compress%3a%3aZlib"></a><b><code class="inline"><span class="w">Compress::Zlib</span></code>
</b>
<p>Upgraded from version 2.008 to 2.020.</p>
</li>
<li><a name="CPAN"></a><b><code class="inline"><span class="w">CPAN</span></code>
</b>
<p>Upgraded from version 1.9205 to 1.9402. <code class="inline"><span class="w">CPAN::FTP</span></code>
 has a local fix to
stop it being too verbose on download failure.</p>
</li>
<li><a name="CPANPLUS"></a><b><code class="inline"><span class="w">CPANPLUS</span></code>
</b>
<p>Upgraded from version 0.84 to 0.88.</p>
</li>
<li><a name="CPANPLUS%3a%3aDist%3a%3aBuild"></a><b><code class="inline"><span class="w">CPANPLUS::Dist::Build</span></code>
</b>
<p>Upgraded from version 0.06_02 to 0.36.</p>
</li>
<li><a name="Cwd"></a><b><code class="inline"><span class="w">Cwd</span></code>
</b>
<p>Upgraded from version 3.25_01 to 3.30.</p>
</li>
<li><a name="Data%3a%3aDumper"></a><b><code class="inline"><span class="w">Data::Dumper</span></code>
</b>
<p>Upgraded from version 2.121_14 to 2.124.</p>
</li>
<li><a name="DB"></a><b><code class="inline"><span class="w">DB</span></code>
</b>
<p>Upgraded from version 1.01 to 1.02.</p>
</li>
<li><a name="DB_File"></a><b><code class="inline"><span class="w">DB_File</span></code>
</b>
<p>Upgraded from version 1.816_1 to 1.820.</p>
</li>
<li><a name="Devel%3a%3aPPPort"></a><b><code class="inline"><span class="w">Devel::PPPort</span></code>
</b>
<p>Upgraded from version 3.13 to 3.19.</p>
</li>
<li><a name="Digest%3a%3aMD5"></a><b><code class="inline"><span class="w">Digest::MD5</span></code>
</b>
<p>Upgraded from version 2.36_01 to 2.39.</p>
</li>
<li><a name="Digest%3a%3aSHA"></a><b><code class="inline"><span class="w">Digest::SHA</span></code>
</b>
<p>Upgraded from version 5.45 to 5.47.</p>
</li>
<li><a name="DirHandle"></a><b><code class="inline"><span class="w">DirHandle</span></code>
</b>
<p>Upgraded from version 1.01 to 1.03.</p>
</li>
<li><a name="Dumpvalue"></a><b><code class="inline"><span class="w">Dumpvalue</span></code>
</b>
<p>Upgraded from version 1.12 to 1.13.</p>
</li>
<li><a name="DynaLoader"></a><b><code class="inline"><span class="w">DynaLoader</span></code>
</b>
<p>Upgraded from version 1.08 to 1.10.</p>
</li>
<li><a name="Encode"></a><b><code class="inline"><span class="w">Encode</span></code>
</b>
<p>Upgraded from version 2.23 to 2.35.</p>
</li>
<li><a name="Errno"></a><b><code class="inline"><span class="w">Errno</span></code>
</b>
<p>Upgraded from version 1.10 to 1.11.</p>
</li>
<li><a name="Exporter"></a><b><code class="inline"><span class="w">Exporter</span></code>
</b>
<p>Upgraded from version 5.62 to 5.63.</p>
</li>
<li><a name="ExtUtils%3a%3aCBuilder"></a><b><code class="inline"><span class="w">ExtUtils::CBuilder</span></code>
</b>
<p>Upgraded from version 0.21 to 0.2602.</p>
</li>
<li><a name="ExtUtils%3a%3aCommand"></a><b><code class="inline"><span class="w">ExtUtils::Command</span></code>
</b>
<p>Upgraded from version 1.13 to 1.16.</p>
</li>
<li><a name="ExtUtils%3a%3aConstant"></a><b><code class="inline"><span class="w">ExtUtils::Constant</span></code>
</b>
<p>Upgraded from 0.20 to 0.22. (Note that neither of these versions are
available on CPAN.)</p>
</li>
<li><a name="ExtUtils%3a%3aEmbed"></a><b><code class="inline"><span class="w">ExtUtils::Embed</span></code>
</b>
<p>Upgraded from version 1.27 to 1.28.</p>
</li>
<li><a name="ExtUtils%3a%3aInstall"></a><b><code class="inline"><span class="w">ExtUtils::Install</span></code>
</b>
<p>Upgraded from version 1.44 to 1.54.</p>
</li>
<li><a name="ExtUtils%3a%3aMakeMaker"></a><b><code class="inline"><span class="w">ExtUtils::MakeMaker</span></code>
</b>
<p>Upgraded from version 6.42 to 6.55_02.</p>
<p>Note that <code class="inline"><span class="w">ExtUtils::MakeMaker::bytes</span></code>
 and <code class="inline"><span class="w">ExtUtils::MakeMaker::vmsish</span></code>

have been removed from this distribution.</p>
</li>
<li><a name="ExtUtils%3a%3aManifest"></a><b><code class="inline"><span class="w">ExtUtils::Manifest</span></code>
</b>
<p>Upgraded from version 1.51_01 to 1.56.</p>
</li>
<li><a name="ExtUtils%3a%3aParseXS"></a><b><code class="inline"><span class="w">ExtUtils::ParseXS</span></code>
</b>
<p>Upgraded from version 2.18_02 to 2.2002.</p>
</li>
<li><a name="Fatal"></a><b><code class="inline"><span class="w">Fatal</span></code>
</b>
<p>Upgraded from version 1.05 to 2.06_01. See also the new pragma <code class="inline"><span class="w">autodie</span></code>
.</p>
</li>
<li><a name="File%3a%3aBasename"></a><b><code class="inline"><span class="w">File::Basename</span></code>
</b>
<p>Upgraded from version 2.76 to 2.77.</p>
</li>
<li><a name="File%3a%3aCompare"></a><b><code class="inline"><span class="w">File::Compare</span></code>
</b>
<p>Upgraded from version 1.1005 to 1.1006.</p>
</li>
<li><a name="File%3a%3aCopy"></a><b><code class="inline"><span class="w">File::Copy</span></code>
</b>
<p>Upgraded from version 2.11 to 2.14.</p>
</li>
<li><a name="File%3a%3aFetch"></a><b><code class="inline"><span class="w">File::Fetch</span></code>
</b>
<p>Upgraded from version 0.14 to 0.20.</p>
</li>
<li><a name="File%3a%3aFind"></a><b><code class="inline"><span class="w">File::Find</span></code>
</b>
<p>Upgraded from version 1.12 to 1.14.</p>
</li>
<li><a name="File%3a%3aPath"></a><b><code class="inline"><span class="w">File::Path</span></code>
</b>
<p>Upgraded from version 2.04 to 2.07_03.</p>
</li>
<li><a name="File%3a%3aSpec"></a><b><code class="inline"><span class="w">File::Spec</span></code>
</b>
<p>Upgraded from version 3.2501 to 3.30.</p>
</li>
<li><a name="File%3a%3astat"></a><b><code class="inline"><span class="w">File::stat</span></code>
</b>
<p>Upgraded from version 1.00 to 1.01.</p>
</li>
<li><a name="File%3a%3aTemp"></a><b><code class="inline"><span class="w">File::Temp</span></code>
</b>
<p>Upgraded from version 0.18 to 0.22.</p>
</li>
<li><a name="FileCache"></a><b><code class="inline"><span class="w">FileCache</span></code>
</b>
<p>Upgraded from version 1.07 to 1.08.</p>
</li>
<li><a name="FileHandle"></a><b><code class="inline"><span class="w">FileHandle</span></code>
</b>
<p>Upgraded from version 2.01 to 2.02.</p>
</li>
<li><a name="Filter%3a%3aSimple"></a><b><code class="inline"><span class="w">Filter::Simple</span></code>
</b>
<p>Upgraded from version 0.82 to 0.84.</p>
</li>
<li><a name="Filter%3a%3aUtil%3a%3aCall"></a><b><code class="inline"><span class="w">Filter::Util::Call</span></code>
</b>
<p>Upgraded from version 1.07 to 1.08.</p>
</li>
<li><a name="FindBin"></a><b><code class="inline"><span class="w">FindBin</span></code>
</b>
<p>Upgraded from version 1.49 to 1.50.</p>
</li>
<li><a name="GDBM_File"></a><b><code class="inline"><span class="w">GDBM_File</span></code>
</b>
<p>Upgraded from version 1.08 to 1.09.</p>
</li>
<li><a name="Getopt%3a%3aLong"></a><b><code class="inline"><span class="w">Getopt::Long</span></code>
</b>
<p>Upgraded from version 2.37 to 2.38.</p>
</li>
<li><a name="Hash%3a%3aUtil%3a%3aFieldHash"></a><b><code class="inline"><span class="w">Hash::Util::FieldHash</span></code>
</b>
<p>Upgraded from version 1.03 to 1.04. This fixes a memory leak.</p>
</li>
<li><a name="I18N%3a%3aCollate"></a><b><code class="inline"><span class="w">I18N::Collate</span></code>
</b>
<p>Upgraded from version 1.00 to 1.01.</p>
</li>
<li><a name="IO"></a><b><code class="inline"><span class="w">IO</span></code>
</b>
<p>Upgraded from version 1.23_01 to 1.25.</p>
<p>This makes non-blocking mode work on Windows in <code class="inline"><span class="w">IO::Socket::INET</span></code>

[CPAN #43573].</p>
</li>
<li><a name="IO%3a%3aCompress%3a%3a*"></a><b><code class="inline"><span class="w">IO::Compress::</span>*</code>
</b>
<p>Upgraded from version 2.008 to 2.020.</p>
</li>
<li><a name="IO%3a%3aDir"></a><b><code class="inline"><span class="w">IO::Dir</span></code>
</b>
<p>Upgraded from version 1.06 to 1.07.</p>
</li>
<li><a name="IO%3a%3aHandle"></a><b><code class="inline"><span class="w">IO::Handle</span></code>
</b>
<p>Upgraded from version 1.27 to 1.28.</p>
</li>
<li><a name="IO%3a%3aSocket"></a><b><code class="inline"><span class="w">IO::Socket</span></code>
</b>
<p>Upgraded from version 1.30_01 to 1.31.</p>
</li>
<li><a name="IO%3a%3aZlib"></a><b><code class="inline"><span class="w">IO::Zlib</span></code>
</b>
<p>Upgraded from version 1.07 to 1.09.</p>
</li>
<li><a name="IPC%3a%3aCmd"></a><b><code class="inline"><span class="w">IPC::Cmd</span></code>
</b>
<p>Upgraded from version 0.40_1 to 0.46.</p>
</li>
<li><a name="IPC%3a%3aOpen3"></a><b><code class="inline"><span class="w">IPC::Open3</span></code>
</b>
<p>Upgraded from version 1.02 to 1.04.</p>
</li>
<li><a name="IPC%3a%3aSysV"></a><b><code class="inline"><span class="w">IPC::SysV</span></code>
</b>
<p>Upgraded from version 1.05 to 2.01.</p>
</li>
<li><a name="lib"></a><b><code class="inline"><span class="w">lib</span></code>
</b>
<p>Upgraded from version 0.5565 to 0.62.</p>
</li>
<li><a name="List%3a%3aUtil"></a><b><code class="inline"><span class="w">List::Util</span></code>
</b>
<p>Upgraded from version 1.19 to 1.21.</p>
</li>
<li><a name="Locale%3a%3aMakeText"></a><b><code class="inline"><span class="w">Locale::MakeText</span></code>
</b>
<p>Upgraded from version 1.12 to 1.13.</p>
</li>
<li><a name="Log%3a%3aMessage"></a><b><code class="inline"><span class="w">Log::Message</span></code>
</b>
<p>Upgraded from version 0.01 to 0.02.</p>
</li>
<li><a name="Math%3a%3aBigFloat"></a><b><code class="inline"><span class="w">Math::BigFloat</span></code>
</b>
<p>Upgraded from version 1.59 to 1.60.</p>
</li>
<li><a name="Math%3a%3aBigInt"></a><b><code class="inline"><span class="w">Math::BigInt</span></code>
</b>
<p>Upgraded from version 1.88 to 1.89.</p>
</li>
<li><a name="Math%3a%3aBigInt%3a%3aFastCalc"></a><b><code class="inline"><span class="w">Math::BigInt::FastCalc</span></code>
</b>
<p>Upgraded from version 0.16 to 0.19.</p>
</li>
<li><a name="Math%3a%3aBigRat"></a><b><code class="inline"><span class="w">Math::BigRat</span></code>
</b>
<p>Upgraded from version 0.21 to 0.22.</p>
</li>
<li><a name="Math%3a%3aComplex"></a><b><code class="inline"><span class="w">Math::Complex</span></code>
</b>
<p>Upgraded from version 1.37 to 1.56.</p>
</li>
<li><a name="Math%3a%3aTrig"></a><b><code class="inline"><span class="w">Math::Trig</span></code>
</b>
<p>Upgraded from version 1.04 to 1.20.</p>
</li>
<li><a name="Memoize"></a><b><code class="inline"><span class="w">Memoize</span></code>
</b>
<p>Upgraded from version 1.01_02 to 1.01_03 (just a minor documentation
change).</p>
</li>
<li><a name="Module%3a%3aBuild"></a><b><code class="inline"><span class="w">Module::Build</span></code>
</b>
<p>Upgraded from version 0.2808_01 to 0.34_02.</p>
</li>
<li><a name="Module%3a%3aCoreList"></a><b><code class="inline"><span class="w">Module::CoreList</span></code>
</b>
<p>Upgraded from version 2.13 to 2.18. This release no longer contains the
<code class="inline"><span class="i">%Module::CoreList::patchlevel</span></code>
 hash.</p>
</li>
<li><a name="Module%3a%3aLoad"></a><b><code class="inline"><span class="w">Module::Load</span></code>
</b>
<p>Upgraded from version 0.12 to 0.16.</p>
</li>
<li><a name="Module%3a%3aLoad%3a%3aConditional"></a><b><code class="inline"><span class="w">Module::Load::Conditional</span></code>
</b>
<p>Upgraded from version 0.22 to 0.30.</p>
</li>
<li><a name="Module%3a%3aLoaded"></a><b><code class="inline"><span class="w">Module::Loaded</span></code>
</b>
<p>Upgraded from version 0.01 to 0.02.</p>
</li>
<li><a name="Module%3a%3aPluggable"></a><b><code class="inline"><span class="w">Module::Pluggable</span></code>
</b>
<p>Upgraded from version 3.6 to 3.9.</p>
</li>
<li><a name="NDBM_File"></a><b><code class="inline"><span class="w">NDBM_File</span></code>
</b>
<p>Upgraded from version 1.07 to 1.08.</p>
</li>
<li><a name="Net%3a%3aPing"></a><b><code class="inline"><span class="w">Net::Ping</span></code>
</b>
<p>Upgraded from version 2.33 to 2.36.</p>
</li>
<li><a name="NEXT"></a><b><code class="inline"><span class="w">NEXT</span></code>
</b>
<p>Upgraded from version 0.60_01 to 0.64.</p>
</li>
<li><a name="Object%3a%3aAccessor"></a><b><code class="inline"><span class="w">Object::Accessor</span></code>
</b>
<p>Upgraded from version 0.32 to 0.34.</p>
</li>
<li><a name="OS2%3a%3aREXX"></a><b><code class="inline"><span class="w">OS2::REXX</span></code>
</b>
<p>Upgraded from version 1.03 to 1.04.</p>
</li>
<li><a name="Package%3a%3aConstants"></a><b><code class="inline"><span class="w">Package::Constants</span></code>
</b>
<p>Upgraded from version 0.01 to 0.02.</p>
</li>
<li><a name="PerlIO"></a><b><code class="inline"><span class="w">PerlIO</span></code>
</b>
<p>Upgraded from version 1.04 to 1.06.</p>
</li>
<li><a name="PerlIO%3a%3avia"></a><b><code class="inline"><span class="w">PerlIO::via</span></code>
</b>
<p>Upgraded from version 0.04 to 0.07.</p>
</li>
<li><a name="Pod%3a%3aMan"></a><b><code class="inline"><span class="w">Pod::Man</span></code>
</b>
<p>Upgraded from version 2.16 to 2.22.</p>
</li>
<li><a name="Pod%3a%3aParser"></a><b><code class="inline"><span class="w">Pod::Parser</span></code>
</b>
<p>Upgraded from version 1.35 to 1.37.</p>
</li>
<li><a name="Pod%3a%3aSimple"></a><b><code class="inline"><span class="w">Pod::Simple</span></code>
</b>
<p>Upgraded from version 3.05 to 3.07.</p>
</li>
<li><a name="Pod%3a%3aText"></a><b><code class="inline"><span class="w">Pod::Text</span></code>
</b>
<p>Upgraded from version 3.08 to 3.13.</p>
</li>
<li><a name="POSIX"></a><b><code class="inline"><span class="w">POSIX</span></code>
</b>
<p>Upgraded from version 1.13 to 1.17.</p>
</li>
<li><a name="Safe"></a><b><code class="inline"><span class="w">Safe</span></code>
</b>
<p>Upgraded from 2.12 to 2.18.</p>
</li>
<li><a name="Scalar%3a%3aUtil"></a><b><code class="inline"><span class="w">Scalar::Util</span></code>
</b>
<p>Upgraded from version 1.19 to 1.21.</p>
</li>
<li><a name="SelectSaver"></a><b><code class="inline"><span class="w">SelectSaver</span></code>
</b>
<p>Upgraded from 1.01 to 1.02.</p>
</li>
<li><a name="SelfLoader"></a><b><code class="inline"><span class="w">SelfLoader</span></code>
</b>
<p>Upgraded from 1.11 to 1.17.</p>
</li>
<li><a name="Socket"></a><b><code class="inline"><span class="w">Socket</span></code>
</b>
<p>Upgraded from 1.80 to 1.82.</p>
</li>
<li><a name="Storable"></a><b><code class="inline"><span class="w">Storable</span></code>
</b>
<p>Upgraded from 2.18 to 2.20.</p>
</li>
<li><a name="Switch"></a><b><code class="inline"><span class="w">Switch</span></code>
</b>
<p>Upgraded from version 2.13 to 2.14. Please see <a href="#Deprecations">Deprecations</a>.</p>
</li>
<li><a name="Symbol"></a><b><code class="inline"><span class="w">Symbol</span></code>
</b>
<p>Upgraded from version 1.06 to 1.07.</p>
</li>
<li><a name="Sys%3a%3aSyslog"></a><b><code class="inline"><span class="w">Sys::Syslog</span></code>
</b>
<p>Upgraded from version 0.22 to 0.27.</p>
</li>
<li><a name="Term%3a%3aANSIColor"></a><b><code class="inline"><span class="w">Term::ANSIColor</span></code>
</b>
<p>Upgraded from version 1.12 to 2.00.</p>
</li>
<li><a name="Term%3a%3aReadLine"></a><b><code class="inline"><span class="w">Term::ReadLine</span></code>
</b>
<p>Upgraded from version 1.03 to 1.04.</p>
</li>
<li><a name="Term%3a%3aUI"></a><b><code class="inline"><span class="w">Term::UI</span></code>
</b>
<p>Upgraded from version 0.18 to 0.20.</p>
</li>
<li><a name="Test%3a%3aHarness"></a><b><code class="inline"><span class="w">Test::Harness</span></code>
</b>
<p>Upgraded from version 2.64 to 3.17.</p>
<p>Note that one side-effect of the 2.x to 3.x upgrade is that the
experimental <code class="inline"><span class="w">Test::Harness::Straps</span></code>
 module (and its supporting
<code class="inline"><span class="w">Assert</span></code>
, <code class="inline"><span class="w">Iterator</span></code>
, <code class="inline"><span class="w">Point</span></code>
 and <code class="inline"><span class="w">Results</span></code>
 modules) have been
removed. If you still need this, then they are available in the
(unmaintained) <code class="inline"><span class="w">Test</span>-<span class="w">Harness</span>-<span class="w">Straps</span></code>
 distribution on CPAN.</p>
</li>
<li><a name="Test%3a%3aSimple"></a><b><code class="inline"><span class="w">Test::Simple</span></code>
</b>
<p>Upgraded from version 0.72 to 0.92.</p>
</li>
<li><a name="Text%3a%3aParseWords"></a><b><code class="inline"><span class="w">Text::ParseWords</span></code>
</b>
<p>Upgraded from version 3.26 to 3.27.</p>
</li>
<li><a name="Text%3a%3aTabs"></a><b><code class="inline"><span class="w">Text::Tabs</span></code>
</b>
<p>Upgraded from version 2007.1117 to 2009.0305.</p>
</li>
<li><a name="Text%3a%3aWrap"></a><b><code class="inline"><span class="w">Text::Wrap</span></code>
</b>
<p>Upgraded from version 2006.1117 to 2009.0305.</p>
</li>
<li><a name="Thread%3a%3aQueue"></a><b><code class="inline"><span class="w">Thread::Queue</span></code>
</b>
<p>Upgraded from version 2.00 to 2.11.</p>
</li>
<li><a name="Thread%3a%3aSemaphore"></a><b><code class="inline"><span class="w">Thread::Semaphore</span></code>
</b>
<p>Upgraded from version 2.01 to 2.09.</p>
</li>
<li><a name="threads"></a><b><code class="inline"><span class="w">threads</span></code>
</b>
<p>Upgraded from version 1.67 to 1.72.</p>
</li>
<li><a name="threads%3a%3ashared"></a><b><code class="inline"><span class="w">threads::shared</span></code>
</b>
<p>Upgraded from version 1.14 to 1.29.</p>
</li>
<li><a name="Tie%3a%3aRefHash"></a><b><code class="inline"><span class="w">Tie::RefHash</span></code>
</b>
<p>Upgraded from version 1.37 to 1.38.</p>
</li>
<li><a name="Tie%3a%3aStdHandle"></a><b><code class="inline"><span class="w">Tie::StdHandle</span></code>
</b>
<p>This has documentation changes, and has been assigned a version for the
first time: version 4.2.</p>
</li>
<li><a name="Time%3a%3aHiRes"></a><b><code class="inline"><span class="w">Time::HiRes</span></code>
</b>
<p>Upgraded from version 1.9711 to 1.9719.</p>
</li>
<li><a name="Time%3a%3aLocal"></a><b><code class="inline"><span class="w">Time::Local</span></code>
</b>
<p>Upgraded from version 1.18 to 1.1901.</p>
</li>
<li><a name="Time%3a%3aPiece"></a><b><code class="inline"><span class="w">Time::Piece</span></code>
</b>
<p>Upgraded from version 1.12 to 1.15.</p>
</li>
<li><a name="Unicode%3a%3aNormalize"></a><b><code class="inline"><span class="w">Unicode::Normalize</span></code>
</b>
<p>Upgraded from version 1.02 to 1.03.</p>
</li>
<li><a name="Unicode%3a%3aUCD"></a><b><code class="inline"><span class="w">Unicode::UCD</span></code>
</b>
<p>Upgraded from version 0.25 to 0.27.</p>
<p><code class="inline"><span class="i">charinfo</span><span class="s">(</span><span class="s">)</span></code>
 now works on Unified CJK code points added to later versions
of Unicode.</p>
<p><code class="inline"><span class="i">casefold</span><span class="s">(</span><span class="s">)</span></code>
 has new fields returned to provide both a simpler interface
and previously missing information. The old fields are retained for
backwards compatibility. Information about Turkic-specific code points is
now returned.</p>
<p>The documentation has been corrected and expanded.</p>
</li>
<li><a name="UNIVERSAL"></a><b><code class="inline"><span class="w">UNIVERSAL</span></code>
</b>
<p>Upgraded from version 1.04 to 1.05.</p>
</li>
<li><a name="Win32"></a><b><code class="inline"><span class="w">Win32</span></code>
</b>
<p>Upgraded from version 0.34 to 0.39.</p>
</li>
<li><a name="Win32API%3a%3aFile"></a><b><code class="inline"><span class="w">Win32API::File</span></code>
</b>
<p>Upgraded from version 0.1001_01 to 0.1101.</p>
</li>
<li><a name="XSLoader"></a><b><code class="inline"><span class="w">XSLoader</span></code>
</b>
<p>Upgraded from version 0.08 to 0.10.</p>
</li>
</ul>
<a name="Utility-Changes"></a><h1>Utility Changes</h1>
<ul>
<li><a name="_h2ph_"></a><b><i>h2ph</i></b>
<p>Now looks in <code class="inline"><span class="w">include</span>-<span class="w">fixed</span></code>
 too, which is a recent addition to gcc's
search path.</p>
</li>
<li><a name="_h2xs_"></a><b><i>h2xs</i></b>
<p>No longer incorrectly treats enum values like macros (Daniel Burr).</p>
<p>Now handles C++ style constants (<code class="inline"><span class="q">//</span></code>
) properly in enums. (A patch from
Rainer Weikusat was used; Daniel Burr also proposed a similar fix).</p>
</li>
<li><a name="_perl5db.pl_"></a><b><i>perl5db.pl</i></b>
<p><code class="inline"><span class="w">LVALUE</span></code>
 subroutines now work under the debugger.</p>
<p>The debugger now correctly handles proxy constant subroutines, and
subroutine stubs.</p>
</li>
<li><a name="_perlthanks_"></a><b><i>perlthanks</i></b>
<p>Perl 5.10.1 adds a new utility <i>perlthanks</i>, which is a variant of
<i>perlbug</i>, but for sending non-bug-reports to the authors and maintainers
of Perl. Getting nothing but bug reports can become a bit demoralising:
we'll see if this changes things.</p>
</li>
</ul>
<a name="New-Documentation"></a><h1>New Documentation</h1>
<ul>
<li><a name="the-perlhaiku-manpage"></a><b><a href="perlhaiku.html">perlhaiku</a></b>
<p>This contains instructions on how to build perl for the Haiku platform.</p>
</li>
<li><a name="the-perlmroapi-manpage"></a><b><a href="perlmroapi.html">perlmroapi</a></b>
<p>This describes the new interface for pluggable Method Resolution Orders.</p>
</li>
<li><a name="the-perlperf-manpage"></a><b><a href="perlperf.html">perlperf</a></b>
<p>This document, by Richard Foley, provides an introduction to the use of
performance and optimization techniques which can be used with particular
reference to perl programs.</p>
</li>
<li><a name="the-perlrepository-manpage"></a><b><a href="perlrepository.html">perlrepository</a></b>
<p>This describes how to access the perl source using the <i>git</i> version
control system.</p>
</li>
<li><a name="the-perlthanks-manpage"></a><b><a href="perlthanks.html">perlthanks</a></b>
<p>This describes the new <i>perlthanks</i> utility.</p>
</li>
</ul>
<a name="Changes-to-Existing-Documentation"></a><h1>Changes to Existing Documentation</h1>
<p>The various large <code class="inline"><span class="w">Changes</span>*</code>
 files (which listed every change made to perl
over the last 18 years) have been removed, and replaced by a small file,
also called <code class="inline"><span class="w">Changes</span></code>
, which just explains how that same information may
be extracted from the git version control system.</p>
<p>The file <i>Porting/patching.pod</i> has been deleted, as it mainly described
interacting with the old Perforce-based repository, which is now obsolete.
Information still relevant has been moved to <a href="perlrepository.html">perlrepository</a>.</p>
<p><a href="perlapi.html">perlapi</a>, <a href="perlintern.html">perlintern</a>, <a href="perlmodlib.html">perlmodlib</a> and <a href="http://search.cpan.org/perldoc/perltoc">perltoc</a> are now all
generated at build time, rather than being shipped as part of the release.</p>
<a name="Performance-Enhancements"></a><h1>Performance Enhancements</h1>
<ul>
<li>
<p>A new internal cache means that <code class="inline"><span class="i">isa</span><span class="s">(</span><span class="s">)</span></code>
 will often be faster.</p>
</li>
<li>
<p>Under <code class="inline"><a class="l_k" href="functions/use.html">use</a> <span class="w">locale</span></code>
, the locale-relevant information is now cached on
read-only values, such as the list returned by <code class="inline"><a class="l_k" href="functions/keys.html">keys</a> <span class="i">%hash</span></code>
. This makes
operations such as <code class="inline"><a class="l_k" href="functions/sort.html">sort</a> <a class="l_k" href="functions/keys.html">keys</a> <span class="i">%hash</span></code>
 in the scope of <code class="inline"><a class="l_k" href="functions/use.html">use</a> <span class="w">locale</span></code>
 much
faster.</p>
</li>
<li>
<p>Empty <code class="inline">DESTROY</code>
 methods are no longer called.</p>
</li>
</ul>
<a name="Installation-and-Configuration-Improvements"></a><h1>Installation and Configuration Improvements</h1>
<a name="_ext%2f_-reorganisation"></a><h2><i>ext/</i> reorganisation</h2>
<p>The layout of directories in <i>ext</i> has been revised. Specifically, all
extensions are now flat, and at the top level, with <code class="inline">/</code> in pathnames
replaced by <code class="inline">-</code>
, so that <i>ext/Data/Dumper/</i> is now <i>ext/Data-Dumper/</i>,
etc.  The names of the extensions as specified to <i>Configure</i>, and as
reported by <code class="inline"><span class="i">%Config::Config</span></code>
 under the keys <code class="inline"><span class="w">dynamic_ext</span></code>
,
<code class="inline"><span class="w">known_extensions</span></code>
, <code class="inline"><span class="w">nonxs_ext</span></code>
 and <code class="inline"><span class="w">static_ext</span></code>
 have not changed, and
still use <code class="inline">/</code>. Hence this change will not have any affect once perl is
installed. However, <code class="inline"><span class="w">Attribute::Handlers</span></code>
, <code class="inline"><span class="w">Safe</span></code>
 and <code class="inline"><span class="w">mro</span></code>
 have now
become extensions in their own right, so if you run <i>Configure</i> with
options to specify an exact list of extensions to build, you will need to
change it to account for this.</p>
<p>For 5.10.2, it is planned that many dual-life modules will have been moved
from <i>lib</i> to <i>ext</i>; again this will have no effect on an installed
perl, but will matter if you invoke <i>Configure</i> with a pre-canned list of
extensions to build.</p>
<a name="Configuration-improvements"></a><h2>Configuration improvements</h2>
<p>If <code class="inline"><span class="w">vendorlib</span></code>
 and <code class="inline"><span class="w">vendorarch</span></code>
 are the same, then they are only added to
<code class="inline"><span class="i">@INC</span></code>
 once.</p>
<p><code class="inline"><span class="i">$Config</span>{<span class="w">usedevel</span>}</code>
 and the C-level <code class="inline"><span class="w">PERL_USE_DEVEL</span></code>
 are now defined if
perl is built with  <code class="inline">-<span class="w">Dusedevel</span></code>
.</p>
<p><i>Configure</i> will enable use of <code class="inline">-<span class="w">fstack</span>-<span class="w">protector</span></code>
, to provide protection
against stack-smashing attacks, if the compiler supports it.</p>
<p><i>Configure</i> will now determine the correct prototypes for re-entrant
functions, and for <code class="inline"><span class="w">gconvert</span></code>
, if you are using a C++ compiler rather
than a C compiler.</p>
<p>On Unix, if you build from a tree containing a git repository, the
configuration process will note the commit hash you have checked out, for
display in the output of <code class="inline"><span class="w">perl</span> -<span class="w">v</span></code>
 and <code class="inline"><span class="w">perl</span> -<span class="w">V</span></code>
. Unpushed local commits
are automatically added to the list of local patches displayed by
<code class="inline"><span class="w">perl</span> -<span class="w">V</span></code>
.</p>
<a name="Compilation-improvements"></a><h2>Compilation improvements</h2>
<p>As part of the flattening of <i>ext</i>, all extensions on all platforms are
built by <i>make_ext.pl</i>. This replaces the Unix-specific
<i>ext/util/make_ext</i>, VMS-specific <i>make_ext.com</i> and Win32-specific
<i>win32/buildext.pl</i>.</p>
<a name="Platform-Specific-Changes"></a><h2>Platform Specific Changes</h2>
<ul>
<li><a name="AIX"></a><b>AIX</b>
<p>Removed <i>libbsd</i> for AIX 5L and 6.1. Only flock() was used from <i>libbsd</i>.</p>
<p>Removed <i>libgdbm</i> for AIX 5L and 6.1. The <i>libgdbm</i> is delivered as an
optional package with the AIX Toolbox. Unfortunately the 64 bit version 
is broken.</p>
<p>Hints changes mean that AIX 4.2 should work again.</p>
</li>
<li><a name="Cygwin"></a><b>Cygwin</b>
<p>On Cygwin we now strip the last number from the DLL. This has been the
behaviour in the cygwin.com build for years. The hints files have been
updated.</p>
</li>
<li><a name="FreeBSD"></a><b>FreeBSD</b>
<p>The hints files now identify the correct threading libraries on FreeBSD 7
and later.</p>
</li>
<li><a name="Irix"></a><b>Irix</b>
<p>We now work around a bizarre preprocessor bug in the Irix 6.5 compiler:
<code class="inline"><span class="w">cc</span> -<span class="w">E</span> -</code>
 unfortunately goes into K&amp;R mode, but <code class="inline"><span class="w">cc</span> -<span class="w">E</span> <span class="w">file</span>.<span class="w">c</span></code>
 doesn't.</p>
</li>
<li><a name="Haiku"></a><b>Haiku</b>
<p>Patches from the Haiku maintainers have been merged in. Perl should now
build on Haiku.</p>
</li>
<li><a name="MirOS-BSD"></a><b>MirOS BSD</b>
<p>Perl should now build on MirOS BSD.</p>
</li>
<li><a name="NetBSD"></a><b>NetBSD</b>
<p>Hints now supports versions 5.*.</p>
</li>
<li><a name="Stratus-VOS"></a><b>Stratus VOS</b>
<p>Various changes from Stratus have been merged in.</p>
</li>
<li><a name="Symbian"></a><b>Symbian</b>
<p>There is now support for Symbian S60 3.2 SDK and S60 5.0 SDK.</p>
</li>
<li><a name="Win32"></a><b>Win32</b>
<p>Improved message window handling means that <code class="inline"><a class="l_k" href="functions/alarm.html">alarm</a></code> and <code class="inline"><a class="l_k" href="functions/kill.html">kill</a></code> messages
will no longer be dropped under race conditions.</p>
</li>
<li><a name="VMS"></a><b>VMS</b>
<p>Reads from the in-memory temporary files of <code class="inline"><span class="w">PerlIO::scalar</span></code>
 used to fail
if <code class="inline"><span class="i">$/</span></code>
 was set to a numeric reference (to indicate record-style reads).
This is now fixed.</p>
<p>VMS now supports <code class="inline"><a class="l_k" href="functions/getgrgid.html">getgrgid</a></code>.</p>
<p>Many improvements and cleanups have been made to the VMS file name handling
and conversion code.</p>
<p>Enabling the <code class="inline"><span class="w">PERL_VMS_POSIX_EXIT</span></code>
 logical name now encodes a POSIX exit
status in a VMS condition value for better interaction with GNV's bash
shell and other utilities that depend on POSIX exit values.  See
<a href="perlvms.html#%24%3f">$? in perlvms</a> for details.</p>
</li>
</ul>
<a name="Selected-Bug-Fixes"></a><h1>Selected Bug Fixes</h1>
<ul>
<li>
<p>5.10.0 inadvertently disabled an optimisation, which caused a measurable
performance drop in list assignment, such as is often used to assign
function parameters from <code class="inline"><span class="i">@_</span></code>
. The optimisation has been re-instated, and
the performance regression fixed.</p>
</li>
<li>
<p>Fixed memory leak on <code class="inline">while <span class="s">(</span><span class="n">1</span><span class="s">)</span> <span class="s">{</span> <a class="l_k" href="functions/map.html">map</a> <span class="n">1</span><span class="cm">,</span> <span class="n">1</span> <span class="s">}</span></code>
 [RT #53038].</p>
</li>
<li>
<p>Some potential coredumps in PerlIO fixed [RT #57322,54828].</p>
</li>
<li>
<p>The debugger now works with lvalue subroutines.</p>
</li>
<li>
<p>The debugger's <code class="inline"><a class="l_k" href="functions/m.html">m</a></code> command was broken on modules that defined constants
[RT #61222].</p>
</li>
<li>
<p><code class="inline"><a class="l_k" href="functions/crypt.html">crypt()</a></code> and string complement could return tainted values for untainted
arguments [RT #59998].</p>
</li>
<li>
<p>The <code class="inline">-<span class="w">i</span>.<span class="w">suffix</span></code>
 command-line switch now recreates the file using
restricted permissions, before changing its mode to match the original
file. This eliminates a potential race condition [RT #60904].</p>
</li>
<li>
<p>On some Unix systems, the value in <code class="inline"><span class="i">$?</span></code>
 would not have the top bit set
(<code class="inline"><span class="i">$?</span> &amp; <span class="n">128</span></code>
) even if the child core dumped.</p>
</li>
<li>
<p>Under some circumstances, $^R could incorrectly become undefined
[RT #57042].</p>
</li>
<li>
<p>(XS) In various hash functions, passing a pre-computed hash to when the
key is UTF-8 might result in an incorrect lookup.</p>
</li>
<li>
<p>(XS) Including <i>XSUB.h</i> before <i>perl.h</i> gave a compile-time error
[RT #57176].</p>
</li>
<li>
<p><code class="inline"><span class="i">$object</span><span class="i">-&gt;isa</span><span class="s">(</span><span class="q">&#39;Foo&#39;</span><span class="s">)</span></code>
 would report false if the package <code class="inline"><span class="w">Foo</span></code>
 didn't
exist, even if the object's <code class="inline"><span class="i">@ISA</span></code>
 contained <code class="inline"><span class="w">Foo</span></code>
.</p>
</li>
<li>
<p>Various bugs in the new-to 5.10.0 mro code, triggered by manipulating
<code class="inline"><span class="i">@ISA</span></code>
, have been found and fixed.</p>
</li>
<li>
<p>Bitwise operations on references could crash the interpreter, e.g.
<code class="inline"><span class="i">$x</span>=\<span class="i">$y</span><span class="sc">;</span> <span class="i">$x</span> |= <span class="q">&quot;foo&quot;</span></code>
 [RT #54956].</p>
</li>
<li>
<p>Patterns including alternation might be sensitive to the internal UTF-8
representation, e.g.</p>
<pre class="verbatim"><ol><li>    <a class="l_k" href="functions/my.html">my</a> <span class="i">$byte</span> = <a class="l_k" href="functions/chr.html">chr</a><span class="s">(</span><span class="n">192</span><span class="s">)</span><span class="sc">;</span></li><li>    <a class="l_k" href="functions/my.html">my</a> <span class="i">$utf8</span> = <a class="l_k" href="functions/chr.html">chr</a><span class="s">(</span><span class="n">192</span><span class="s">)</span><span class="sc">;</span> <span class="i">utf8::upgrade</span><span class="s">(</span><span class="i">$utf8</span><span class="s">)</span><span class="sc">;</span></li><li>    <span class="i">$utf8</span> =~ <span class="q">/$byte|X}/i</span><span class="sc">;</span>	<span class="c"># failed in 5.10.0</span></li></ol></pre></li>
<li>
<p>Within UTF8-encoded Perl source files (i.e. where <code class="inline"><a class="l_k" href="functions/use.html">use</a> <span class="w">utf8</span></code>
 is in
effect), double-quoted literal strings could be corrupted where a <code class="inline">\<span class="w">xNN</span></code>
,
<code class="inline">\0NNN</code> or <code class="inline">\<span class="w">N</span><span class="s">{</span><span class="s">}</span></code>
 is followed by a literal character with ordinal value
greater than 255 [RT #59908].</p>
</li>
<li>
<p><code class="inline"><span class="w">B::Deparse</span></code>
 failed to correctly deparse various constructs:
<code class="inline"><a class="l_k" href="functions/readpipe.html">readpipe</a> <span class="w">STRING</span></code>
 [RT #62428], <code class="inline"><span class="i">CORE::require</span><span class="s">(</span><span class="w">STRING</span><span class="s">)</span></code>
 [RT #62488],
<code class="inline"><a name="foo"></a>sub <span class="m">foo(_)</span></code>
 [RT #62484].</p>
</li>
<li>
<p>Using <code class="inline"><a class="l_k" href="functions/setpgrp.html">setpgrp()</a></code> with no arguments could corrupt the perl stack.</p>
</li>
<li>
<p>The block form of <code class="inline"><a class="l_k" href="functions/eval.html">eval</a></code> is now specifically trappable by <code class="inline"><span class="w">Safe</span></code>
 and
<code class="inline"><span class="w">ops</span></code>
.  Previously it was erroneously treated like string <code class="inline"><a class="l_k" href="functions/eval.html">eval</a></code>.</p>
</li>
<li>
<p>In 5.10.0, the two characters <code class="inline">[~</code> were sometimes parsed as the smart
match operator (<code class="inline">~~</code>
) [RT #63854].</p>
</li>
<li>
<p>In 5.10.0, the <code class="inline"><span class="i">*</span></code>
 quantifier in patterns was sometimes treated as
<code class="inline"><span class="s">{</span><span class="n">0</span><span class="cm">,</span><span class="n">32767</span><span class="s">}</span></code>
 [RT #60034, #60464]. For example, this match would fail:</p>
<pre class="verbatim"><ol><li>    <span class="s">(</span><span class="q">&quot;ab&quot;</span> x <span class="n">32768</span><span class="s">)</span> =~ <span class="q">/^(ab)*$/</span></li></ol></pre></li>
<li>
<p><code class="inline"><a class="l_k" href="functions/shmget.html">shmget</a></code> was limited to a 32 bit segment size on a 64 bit OS [RT #63924].</p>
</li>
<li>
<p>Using <code class="inline"><a class="l_k" href="functions/next.html">next</a></code> or <code class="inline"><a class="l_k" href="functions/last.html">last</a></code> to exit a <code class="inline">given</code>
 block no longer produces a
spurious warning like the following:</p>
<pre class="verbatim"><ol><li>    <span class="w">Exiting</span> given <span class="w">via</span> <a class="l_k" href="functions/last.html">last</a> <span class="j">at</span> <span class="w">foo</span>.<span class="w">pl</span> <span class="w">line</span> <span class="n">123</span></li></ol></pre></li>
<li>
<p>On Windows, <code class="inline"><span class="q">&#39;.\foo&#39;</span></code>
 and <code class="inline"><span class="q">&#39;..\foo&#39;</span></code>
  were treated differently than
<code class="inline"><span class="q">&#39;./foo&#39;</span></code>
 and <code class="inline"><span class="q">&#39;../foo&#39;</span></code>
 by <code class="inline"><a class="l_k" href="functions/do.html">do</a></code> and <code class="inline"><a class="l_k" href="functions/require.html">require</a></code> [RT #63492].</p>
</li>
<li>
<p>Assigning a format to a glob could corrupt the format; e.g.:</p>
<pre class="verbatim"><ol><li>     <span class="i">*bar</span>=<span class="i">*foo</span>{<span class="w">FORMAT</span>}<span class="sc">;</span> <span class="c"># foo format now bad</span></li></ol></pre></li>
<li>
<p>Attempting to coerce a typeglob to a string or number could cause an
assertion failure. The correct error message is now generated,
<code class="inline">Can't coerce GLOB to <i>$type</i></code>.</p>
</li>
<li>
<p>Under <code class="inline"><a class="l_k" href="functions/use.html">use</a> <span class="w">filetest</span> <span class="q">&#39;access&#39;</span></code>
, <code class="inline">-x</code>
 was using the wrong access mode. This
has been fixed [RT #49003].</p>
</li>
<li>
<p><code class="inline"><a class="l_k" href="functions/length.html">length</a></code> on a tied scalar that returned a Unicode value would not be
correct the first time. This has been fixed.</p>
</li>
<li>
<p>Using an array <code class="inline"><a class="l_k" href="functions/tie.html">tie</a></code> inside in array <code class="inline"><a class="l_k" href="functions/tie.html">tie</a></code> could SEGV. This has been
fixed. [RT #51636]</p>
</li>
<li>
<p>A race condition inside <code class="inline"><span class="i">PerlIOStdio_close</span><span class="s">(</span><span class="s">)</span></code>
 has been identified and
fixed. This used to cause various threading issues, including SEGVs.</p>
</li>
<li>
<p>In <code class="inline"><a class="l_k" href="functions/unpack.html">unpack</a></code>, the use of <code class="inline"><span class="s">(</span><span class="s">)</span></code>
 groups in scalar context was internally
placing a list on the interpreter's stack, which manifested in various
ways, including SEGVs.  This is now fixed [RT #50256].</p>
</li>
<li>
<p>Magic was called twice in <code class="inline"><a class="l_k" href="functions/substr.html">substr</a></code>, <code class="inline">\<span class="i">&amp;$x</span></code>
, <code class="inline"><a class="l_k" href="functions/tie.html">tie</a> <span class="i">$x</span><span class="cm">,</span> <span class="i">$m</span></code>
 and <code class="inline"><a class="l_k" href="functions/chop.html">chop</a></code>.
These have all been fixed.</p>
</li>
<li>
<p>A 5.10.0 optimisation to clear the temporary stack within the implicit
loop of <code class="inline"><a class="l_k" href="functions/s.html">s///ge</a></code> has been reverted, as it turned out to be the cause of
obscure bugs in seemingly unrelated parts of the interpreter [commit 
ef0d4e17921ee3de].</p>
</li>
<li>
<p>The line numbers for warnings inside <code class="inline">elsif</code>
 are now correct.</p>
</li>
<li>
<p>The <code class="inline">..</code>
 operator now works correctly with ranges whose ends are at or
close to the values of the smallest and largest integers.</p>
</li>
<li>
<p><code class="inline"><a class="l_k" href="functions/binmode.html">binmode</a> <span class="w">STDIN</span><span class="cm">,</span> <span class="q">&#39;:raw&#39;</span></code>
 could lead to segmentation faults on some platforms.
This has been fixed [RT #54828].</p>
</li>
<li>
<p>An off-by-one error meant that <code class="inline"><a class="l_k" href="functions/index.html">index</a> <span class="i">$str</span><span class="cm">,</span> ...</code>
 was effectively being
executed as <code class="inline"><a class="l_k" href="functions/index.html">index</a> <span class="q">&quot;$str\0&quot;</span><span class="cm">,</span> ...</code>
. This has been fixed [RT #53746].</p>
</li>
<li>
<p>Various leaks associated with named captures in regexes have been fixed
[RT #57024].</p>
</li>
<li>
<p>A weak reference to a hash would leak. This was affecting <code class="inline"><span class="w">DBI</span></code>

[RT #56908].</p>
</li>
<li>
<p>Using (?|) in a regex could cause a segfault [RT #59734].</p>
</li>
<li>
<p>Use of a UTF-8 <code class="inline"><a class="l_k" href="functions/tr.html">tr//</a></code> within a closure could cause a segfault [RT #61520].</p>
</li>
<li>
<p>Calling <code class="inline"><span class="i">sv_chop</span><span class="s">(</span><span class="s">)</span></code>
 or otherwise upgrading an SV could result in an
unaligned 64-bit access on the SPARC architecture [RT #60574].</p>
</li>
<li>
<p>In the 5.10.0 release, <code class="inline"><span class="w">inc_version_list</span></code>
 would incorrectly list
<code class="inline"><span class="n">5.10</span>.<span class="i">*</span></code>
 after <code class="inline"><span class="n">5.8</span>.<span class="i">*</span></code>
; this affected the <code class="inline"><span class="i">@INC</span></code>
 search order
[RT #67628].</p>
</li>
<li>
<p>In 5.10.0, <code class="inline"><a class="l_k" href="functions/pack.html">pack</a> <span class="q">&quot;a*&quot;</span><span class="cm">,</span> <span class="i">$tainted_value</span></code>
 returned a non-tainted value
[RT #52552].</p>
</li>
<li>
<p>In 5.10.0, <code class="inline"><a class="l_k" href="functions/printf.html">printf</a></code> and <code class="inline"><a class="l_k" href="functions/sprintf.html">sprintf</a></code> could produce the fatal error
<code class="inline"><span class="j">panic:</span> <span class="w">utf8_mg_pos_cache_update</span></code>
 when printing UTF-8 strings
[RT #62666].</p>
</li>
<li>
<p>In the 5.10.0 release, a dynamically created <code class="inline">AUTOLOAD</code>
 method might be
missed (method cache issue) [RT #60220,60232].</p>
</li>
<li>
<p>In the 5.10.0 release, a combination of <code class="inline"><a class="l_k" href="functions/use.html">use</a> <span class="w">feature</span></code>
 and <code class="inline">//ee</code> could
cause a memory leak [RT #63110].</p>
</li>
<li>
<p><code class="inline">-C</code>
 on the shebang (<code class="inline"><span class="c">#!</span></code>
) line is once more permitted if it is also
specified on the command line. <code class="inline">-C</code>
 on the shebang line used to be a
silent no-op <i>if</i> it was not also on the command line, so perl 5.10.0
disallowed it, which broke some scripts. Now perl checks whether it is
also on the command line and only dies if it is not [RT #67880].</p>
</li>
<li>
<p>In 5.10.0, certain types of re-entrant regular expression could crash,
or cause the following assertion failure [RT #60508]:</p>
<pre class="verbatim"><ol><li>    Assertion rx-&gt;sublen &gt;= (s - rx-&gt;subbeg) + i failed</li></ol></pre></li>
</ul>
<a name="New-or-Changed-Diagnostics"></a><h1>New or Changed Diagnostics</h1>
<ul>
<li><a name="panic%3a-sv_chop-%25s"></a><b><code class="inline"><span class="j">panic:</span> <span class="w">sv_chop</span> <span class="i">%s</span></code>
</b>
<p>This new fatal error occurs when the C routine <code class="inline"><span class="i">Perl_sv_chop</span><span class="s">(</span><span class="s">)</span></code>
 was
passed a position that is not within the scalar's string buffer. This
could be caused by buggy XS code, and at this point recovery is not
possible.</p>
</li>
<li><a name="Can't-locate-package-%25s-for-the-parents-of-%25s"></a><b><code class="inline"><span class="w">Can&#39;t</span> <span class="w">locate</span> <a class="l_k" href="functions/package.html">package</a> <span class="i">%s</span> for <span class="w">the</span> <span class="w">parents</span> <span class="w">of</span> <span class="i">%s</span></code>
</b>
<p>This warning has been removed. In general, it only got produced in
conjunction with other warnings, and removing it allowed an ISA lookup
optimisation to be added.</p>
</li>
<li><a name="v-string-in-use%2frequire-is-non-portable"></a><b><code class="inline">v-string in use/require is non-portable</code></b>
<p>This warning has been removed.</p>
</li>
<li><a name="Deep-recursion-on-subroutine-%22%25s%22"></a><b><code class="inline"><span class="w">Deep</span> <span class="w">recursion</span> <span class="w">on</span> <span class="w">subroutine</span> <span class="q">&quot;%s&quot;</span></code>
</b>
<p>It is now possible to change the depth threshold for this warning from the
default of 100, by recompiling the <i>perl</i> binary, setting the C
pre-processor macro <code class="inline"><span class="w">PERL_SUB_DEPTH_WARN</span></code>
 to the desired value.</p>
</li>
</ul>
<a name="Changed-Internals"></a><h1>Changed Internals</h1>
<ul>
<li>
<p>The J.R.R. Tolkien quotes at the head of C source file have been checked and
proper citations added, thanks to a patch from Tom Christiansen.</p>
</li>
<li>
<p><code class="inline"><span class="i">vcroak</span><span class="s">(</span><span class="s">)</span></code>
 now accepts a null first argument. In addition, a full audit
was made of the "not NULL" compiler annotations, and those for several
other internal functions were corrected.</p>
</li>
<li>
<p>New macros <code class="inline"><span class="w">dSAVEDERRNO</span></code>
, <code class="inline"><span class="w">dSAVE_ERRNO</span></code>
, <code class="inline"><span class="w">SAVE_ERRNO</span></code>
, <code class="inline"><span class="w">RESTORE_ERRNO</span></code>

have been added to formalise the temporary saving of the <code class="inline"><span class="w">errno</span></code>

variable.</p>
</li>
<li>
<p>The function <code class="inline"><span class="w">Perl_sv_insert_flags</span></code>
 has been added to augment
<code class="inline"><span class="w">Perl_sv_insert</span></code>
.</p>
</li>
<li>
<p>The function <code class="inline"><span class="i">Perl_newSV_type</span><span class="s">(</span><span class="w">type</span><span class="s">)</span></code>
 has been added, equivalent to
<code class="inline"><span class="i">Perl_newSV</span><span class="s">(</span><span class="s">)</span></code>
 followed by <code class="inline"><span class="i">Perl_sv_upgrade</span><span class="s">(</span><span class="w">type</span><span class="s">)</span></code>
.</p>
</li>
<li>
<p>The function <code class="inline"><span class="i">Perl_newSVpvn_flags</span><span class="s">(</span><span class="s">)</span></code>
 has been added, equivalent to
<code class="inline"><span class="i">Perl_newSVpvn</span><span class="s">(</span><span class="s">)</span></code>
 and then performing the action relevant to the flag.</p>
<p>Two flag bits are currently supported.</p>
<ul>
<li><a name="SVf_UTF8"></a><b><code class="inline"><span class="w">SVf_UTF8</span></code>
</b>
<p>This will call <code class="inline"><span class="i">SvUTF8_on</span><span class="s">(</span><span class="s">)</span></code>
 for you. (Note that this does not convert an
sequence of ISO 8859-1 characters to UTF-8). A wrapper, <code class="inline"><span class="i">newSVpvn_utf8</span><span class="s">(</span><span class="s">)</span></code>

is available for this.</p>
</li>
<li><a name="SVs_TEMP"></a><b><code class="inline"><span class="w">SVs_TEMP</span></code>
</b>
<p>Call <code class="inline"><span class="i">sv_2mortal</span><span class="s">(</span><span class="s">)</span></code>
 on the new SV.</p>
</li>
</ul>
<p>There is also a wrapper that takes constant strings, <code class="inline"><span class="i">newSVpvs_flags</span><span class="s">(</span><span class="s">)</span></code>
.</p>
</li>
<li>
<p>The function <code class="inline"><span class="w">Perl_croak_xs_usage</span></code>
 has been added as a wrapper to
<code class="inline"><span class="w">Perl_croak</span></code>
.</p>
</li>
<li>
<p>The functions <code class="inline"><span class="w">PerlIO_find_layer</span></code>
 and <code class="inline"><span class="w">PerlIO_list_alloc</span></code>
 are now
exported.</p>
</li>
<li>
<p><code class="inline"><span class="w">PL_na</span></code>
 has been exterminated from the core code, replaced by local STRLEN
temporaries, or <code class="inline"><span class="i">*_nolen</span><span class="s">(</span><span class="s">)</span></code>
 calls. Either approach is faster than <code class="inline"><span class="w">PL_na</span></code>
,
which is a pointer deference into the interpreter structure under ithreads,
and a global variable otherwise.</p>
</li>
<li>
<p><code class="inline"><span class="i">Perl_mg_free</span><span class="s">(</span><span class="s">)</span></code>
 used to leave freed memory accessible via SvMAGIC() on
the scalar. It now updates the linked list to remove each piece of magic
as it is freed.</p>
</li>
<li>
<p>Under ithreads, the regex in <code class="inline"><span class="w">PL_reg_curpm</span></code>
 is now reference counted. This
eliminates a lot of hackish workarounds to cope with it not being reference
counted.</p>
</li>
<li>
<p><code class="inline"><span class="i">Perl_mg_magical</span><span class="s">(</span><span class="s">)</span></code>
 would sometimes incorrectly turn on <code class="inline"><span class="i">SvRMAGICAL</span><span class="s">(</span><span class="s">)</span></code>
.
This has been fixed.</p>
</li>
<li>
<p>The <i>public</i> IV and NV flags are now not set if the string value has
trailing "garbage". This behaviour is consistent with not setting the
public IV or NV flags if the value is out of range for the type.</p>
</li>
<li>
<p>SV allocation tracing has been added to the diagnostics enabled by <code class="inline">-<span class="w">Dm</span></code>
.
The tracing can alternatively output via the <code class="inline"><span class="w">PERL_MEM_LOG</span></code>
 mechanism, if
that was enabled when the <i>perl</i> binary was compiled.</p>
</li>
<li>
<p>Uses of <code class="inline"><span class="w">Nullav</span></code>
, <code class="inline"><span class="w">Nullcv</span></code>
, <code class="inline"><span class="w">Nullhv</span></code>
, <code class="inline"><span class="w">Nullop</span></code>
, <code class="inline"><span class="w">Nullsv</span></code>
 etc have been
replaced by <code class="inline"><span class="w">NULL</span></code>
 in the core code, and non-dual-life modules, as <code class="inline"><span class="w">NULL</span></code>

is clearer to those unfamiliar with the core code.</p>
</li>
<li>
<p>A macro <code class="inline"><span class="i">MUTABLE_PTR</span><span class="s">(</span><span class="w">p</span><span class="s">)</span></code>
 has been added, which on (non-pedantic) gcc will
not cast away <code class="inline"><span class="w">const</span></code>
, returning a <code class="inline"><span class="w">void</span> *</code>
. Macros <code class="inline"><span class="i">MUTABLE_SV</span><span class="s">(</span><span class="w">av</span><span class="s">)</span></code>
,
<code class="inline"><span class="i">MUTABLE_SV</span><span class="s">(</span><span class="w">cv</span><span class="s">)</span></code>
 etc build on this, casting to <code class="inline"><span class="w">AV</span> *</code>
 etc without
casting away <code class="inline"><span class="w">const</span></code>
. This allows proper compile-time auditing of
<code class="inline"><span class="w">const</span></code>
 correctness in the core, and helped picked up some errors (now
fixed).</p>
</li>
<li>
<p>Macros <code class="inline"><span class="i">mPUSHs</span><span class="s">(</span><span class="s">)</span></code>
 and <code class="inline"><span class="i">mXPUSHs</span><span class="s">(</span><span class="s">)</span></code>
 have been added, for pushing SVs on the
stack and mortalizing them.</p>
</li>
<li>
<p>Use of the private structure <code class="inline"><span class="w">mro_meta</span></code>
 has changed slightly. Nothing
outside the core should be accessing this directly anyway.</p>
</li>
<li>
<p>A new tool, <code class="inline"><span class="w">Porting</span>/<span class="w">expand</span>-<span class="w">macro</span>.<span class="w">pl</span></code>
 has been added, that allows you
to view how a C preprocessor macro would be expanded when compiled.
This is handy when trying to decode the macro hell that is the perl
guts.</p>
</li>
</ul>
<a name="New-Tests"></a><h1>New Tests</h1>
<p>Many modules updated from CPAN incorporate new tests.</p>
<p>Several tests that have the potential to hang forever if they fail now
incorporate a "watchdog" functionality that will kill them after a timeout,
which helps ensure that <code class="inline"><span class="w">make</span> <span class="w">test</span></code>
 and <code class="inline"><span class="w">make</span> <span class="w">test_harness</span></code>
 run to
completion automatically. (Jerry Hedden).</p>
<p>Some core-specific tests have been added:</p>
<ul>
<li><a name="t%2fcomp%2fretainedlines.t"></a><b>t/comp/retainedlines.t</b>
<p>Check that the debugger can retain source lines from <code class="inline"><a class="l_k" href="functions/eval.html">eval</a></code>.</p>
</li>
<li><a name="t%2fio%2fperlio_fail.t"></a><b>t/io/perlio_fail.t</b>
<p>Check that bad layers fail.</p>
</li>
<li><a name="t%2fio%2fperlio_leaks.t"></a><b>t/io/perlio_leaks.t</b>
<p>Check that PerlIO layers are not leaking.</p>
</li>
<li><a name="t%2fio%2fperlio_open.t"></a><b>t/io/perlio_open.t</b>
<p>Check that certain special forms of open work.</p>
</li>
<li><a name="t%2fio%2fperlio.t"></a><b>t/io/perlio.t</b>
<p>General PerlIO tests.</p>
</li>
<li><a name="t%2fio%2fpvbm.t"></a><b>t/io/pvbm.t</b>
<p>Check that there is no unexpected interaction between the internal types
<code class="inline"><span class="w">PVBM</span></code>
 and <code class="inline"><span class="w">PVGV</span></code>
.</p>
</li>
<li><a name="t%2fmro%2fpackage_aliases.t"></a><b>t/mro/package_aliases.t</b>
<p>Check that mro works properly in the presence of aliased packages.</p>
</li>
<li><a name="t%2fop%2fdbm.t"></a><b>t/op/dbm.t</b>
<p>Tests for <code class="inline"><a class="l_k" href="functions/dbmopen.html">dbmopen</a></code> and <code class="inline"><a class="l_k" href="functions/dbmclose.html">dbmclose</a></code>.</p>
</li>
<li><a name="t%2fop%2findex_thr.t"></a><b>t/op/index_thr.t</b>
<p>Tests for the interaction of <code class="inline"><a class="l_k" href="functions/index.html">index</a></code> and threads.</p>
</li>
<li><a name="t%2fop%2fpat_thr.t"></a><b>t/op/pat_thr.t</b>
<p>Tests for the interaction of esoteric patterns and threads.</p>
</li>
<li><a name="t%2fop%2fqr_gc.t"></a><b>t/op/qr_gc.t</b>
<p>Test that <code class="inline"><a class="l_k" href="functions/qr.html">qr</a></code> doesn't leak.</p>
</li>
<li><a name="t%2fop%2freg_email_thr.t"></a><b>t/op/reg_email_thr.t</b>
<p>Tests for the interaction of regex recursion and threads.</p>
</li>
<li><a name="t%2fop%2fregexp_qr_embed_thr.t"></a><b>t/op/regexp_qr_embed_thr.t</b>
<p>Tests for the interaction of patterns with embedded <code class="inline"><a class="l_k" href="functions/qr.html">qr//</a></code> and threads.</p>
</li>
<li><a name="t%2fop%2fregexp_unicode_prop.t"></a><b>t/op/regexp_unicode_prop.t</b>
<p>Tests for Unicode properties in regular expressions.</p>
</li>
<li><a name="t%2fop%2fregexp_unicode_prop_thr.t"></a><b>t/op/regexp_unicode_prop_thr.t</b>
<p>Tests for the interaction of Unicode properties and threads.</p>
</li>
<li><a name="t%2fop%2freg_nc_tie.t"></a><b>t/op/reg_nc_tie.t</b>
<p>Test the tied methods of <code class="inline"><span class="w">Tie::Hash::NamedCapture</span></code>
.</p>
</li>
<li><a name="t%2fop%2freg_posixcc.t"></a><b>t/op/reg_posixcc.t</b>
<p>Check that POSIX character classes behave consistently.</p>
</li>
<li><a name="t%2fop%2fre.t"></a><b>t/op/re.t</b>
<p>Check that exportable <code class="inline"><span class="w">re</span></code>
 functions in <i>universal.c</i> work.</p>
</li>
<li><a name="t%2fop%2fsetpgrpstack.t"></a><b>t/op/setpgrpstack.t</b>
<p>Check that <code class="inline"><a class="l_k" href="functions/setpgrp.html">setpgrp</a></code> works.</p>
</li>
<li><a name="t%2fop%2fsubstr_thr.t"></a><b>t/op/substr_thr.t</b>
<p>Tests for the interaction of <code class="inline"><a class="l_k" href="functions/substr.html">substr</a></code> and threads.</p>
</li>
<li><a name="t%2fop%2fupgrade.t"></a><b>t/op/upgrade.t</b>
<p>Check that upgrading and assigning scalars works.</p>
</li>
<li><a name="t%2funi%2flex_utf8.t"></a><b>t/uni/lex_utf8.t</b>
<p>Check that Unicode in the lexer works.</p>
</li>
<li><a name="t%2funi%2ftie.t"></a><b>t/uni/tie.t</b>
<p>Check that Unicode and <code class="inline"><a class="l_k" href="functions/tie.html">tie</a></code> work.</p>
</li>
</ul>
<a name="Known-Problems"></a><h1>Known Problems</h1>
<p>This is a list of some significant unfixed bugs, which are regressions
from either 5.10.0 or 5.8.x.</p>
<ul>
<li>
<p><code class="inline"><span class="w">List::Util::first</span></code>
 misbehaves in the presence of a lexical <code class="inline"><span class="i">$_</span></code>

(typically introduced by <code class="inline"><a class="l_k" href="functions/my.html">my</a> <span class="i">$_</span></code>
 or implicitly by <code class="inline">given</code>
). The variable
which gets set for each iteration is the package variable <code class="inline"><span class="i">$_</span></code>
, not the
lexical <code class="inline"><span class="i">$_</span></code>
 [RT #67694].</p>
<p>A similar issue may occur in other modules that provide functions which
take a block as their first argument, like</p>
<pre class="verbatim"><ol><li>    <span class="i">foo</span> <span class="s">{</span> ... <span class="i">$_</span> ...<span class="s">}</span> <span class="w">list</span></li></ol></pre></li>
<li>
<p>The <code class="inline"><span class="w">charnames</span></code>
 pragma may generate a run-time error when a regex is
interpolated [RT #56444]:</p>
<pre class="verbatim"><ol><li>    <a class="l_k" href="functions/use.html">use</a> <span class="w">charnames</span> <span class="q">&#39;:full&#39;</span><span class="sc">;</span></li><li>    <a class="l_k" href="functions/my.html">my</a> <span class="i">$r1</span> = <span class="q">qr/\N{THAI CHARACTER SARA I}/</span><span class="sc">;</span></li><li>    <span class="q">&quot;foo&quot;</span> =~ <span class="i">$r1</span><span class="sc">;</span>    <span class="c"># okay</span></li><li>    <span class="q">&quot;foo&quot;</span> =~ <span class="q">/$r1+/</span><span class="sc">;</span> <span class="c"># runtime error</span></li></ol></pre><p>A workaround is to generate the character outside of the regex:</p>
<pre class="verbatim"><ol><li>    <a class="l_k" href="functions/my.html">my</a> <span class="i">$a</span> = <span class="q">&quot;\N{THAI CHARACTER SARA I}&quot;</span><span class="sc">;</span></li><li>    <a class="l_k" href="functions/my.html">my</a> <span class="i">$r1</span> = <span class="q">qr/$a/</span><span class="sc">;</span></li></ol></pre></li>
<li>
<p>Some regexes may run much more slowly when run in a child thread compared
with the thread the pattern was compiled into [RT #55600].</p>
</li>
</ul>
<a name="Deprecations"></a><h1>Deprecations</h1>
<p>The following items are now deprecated.</p>
<ul>
<li>
<p><code class="inline"><span class="w">Switch</span></code>
 is buggy and should be avoided. From perl 5.11.0 onwards, it is
intended that any use of the core version of this module will emit a
warning, and that the module will eventually be removed from the core
(probably in perl 5.14.0). See <a href="perlsyn.html#Switch-statements">Switch statements in perlsyn</a> for its
replacement.</p>
</li>
<li>
<p><code class="inline"><span class="w">suidperl</span></code>
 will be removed in 5.12.0. This provides a mechanism to
emulate setuid permission bits on systems that don't support it properly.</p>
</li>
</ul>
<a name="Acknowledgements"></a><h1>Acknowledgements</h1>
<p>Some of the work in this release was funded by a TPF grant.</p>
<p>Nicholas Clark officially retired from maintenance pumpking duty at the
end of 2008; however in reality he has put much effort in since then to
help get 5.10.1 into a fit state to be released, including writing a
considerable chunk of this perldelta.</p>
<p>Steffen Mueller and David Golden in particular helped getting CPAN modules
polished and synchronised with their in-core equivalents.</p>
<p>Craig Berry was tireless in getting maint to run under VMS, no matter how
many times we broke it for him.</p>
<p>The other core committers contributed most of the changes, and applied most
of the patches sent in by the hundreds of contributors listed in <i>AUTHORS</i>.</p>
<p>(Sorry to all the people I haven't mentioned by name).</p>
<p>Finally, thanks to Larry Wall, without whom none of this would be
necessary.</p>
<a name="Reporting-Bugs"></a><h1>Reporting Bugs</h1>
<p>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 <a href="http://rt.perl.org/perlbug/">http://rt.perl.org/perlbug/</a> .  There may also be
information at <a href="http://www.perl.org/">http://www.perl.org/</a> , the Perl Home Page.</p>
<p>If you believe you have an unreported bug, please run the <b>perlbug</b>
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 <code class="inline"><span class="w">perl</span> -<span class="w">V</span></code>
, will be sent off to perlbug@perl.org to be
analysed by the Perl porting team.</p>
<p>If the bug you are reporting has security implications, which make it
inappropriate to send to a publicly archived mailing list, then please send
it to perl5-security-report@perl.org. This points to a closed subscription
unarchived mailing list, which includes
all the core committers, who will be able
to help assess the impact of issues, figure out a resolution, and help
co-ordinate the release of patches to mitigate or fix the problem across all
platforms on which Perl is supported. Please only use this address for
security issues in the Perl core, not for modules independently
distributed on CPAN.</p>
<a name="SEE-ALSO"></a><h1>SEE ALSO</h1>
<p>The <i>Changes</i> file for an explanation of how to view exhaustive details
on what changed.</p>
<p>The <i>INSTALL</i> file for how to build Perl.</p>
<p>The <i>README</i> file for general stuff.</p>
<p>The <i>Artistic</i> and <i>Copying</i> files for copyright information.</p>




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