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Section: Perl Programmers Reference Guide (1)
Updated: 2009-02-12
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perl588delta - what is new for perl v5.8.8  


This document describes differences between the 5.8.7 release and the 5.8.8 release.  

Incompatible Changes

There are no changes intentionally incompatible with 5.8.7. If any exist, they are bugs and reports are welcome.  

Core Enhancements

chdir, chmod and chown can now work on filehandles as well as filenames, if the system supports respectively fchdir, fchmod and fchown, thanks to a patch provided by Gisle Aas.

Modules and Pragmata

Attribute::Handlers upgraded to version 0.78_02
Documentation typo fix
attrs upgraded to version 1.02
Internal cleanup only
autouse upgraded to version 1.05
Simplified implementation
B upgraded to version 1.09_01
The inheritance hierarchy of the B:: modules has been corrected; B::NV now inherits from B::SV (instead of B::IV).
blib upgraded to version 1.03
Documentation typo fix
ByteLoader upgraded to version 0.06
Internal cleanup
CGI upgraded to version 3.15
Extraneous ? from self_url() removed
scrolling_list() select attribute fixed
virtual_port now works properly with the https protocol
upload_hook() and append() now works in function-oriented mode
POST_MAX doesn't cause the client to hang any more
Automatic tab indexes are now disabled and new -tabindex pragma has been added to turn automatic indexes back on
end_form() doesn't emit empty (and non-validating) <div>
CGI::Carp works better in certain mod_perl configurations
Setting $CGI::TMPDIRECTORY is now effective
Enhanced documentation
charnames upgraded to version 1.05
viacode() now accept hex strings and has been optimized.
CPAN upgraded to version 1.76_02
1 minor bug fix for Win32
Cwd upgraded to version 3.12
canonpath() on Win32 now collapses foo\.. sections correctly.
Improved behaviour on Symbian OS.
Enhanced documentation and typo fixes
Internal cleanup
Data::Dumper upgraded to version 2.121_08
A problem where Data::Dumper would sometimes update the iterator state of hashes has been fixed
Numeric labels now work
Internal cleanup
DB upgraded to version 1.01
A problem where the state of the regexp engine would sometimes get clobbered when running under the debugger has been fixed.
DB_File upgraded to version 1.814
Adds support for Berkeley DB 4.4.
Devel::DProf upgraded to version 20050603.00
Internal cleanup
Devel::Peek upgraded to version 1.03
Internal cleanup
Devel::PPPort upgraded to version 3.06_01
--compat-version argument checking has been improved
Files passed on the command line are filtered by default
--nofilter option to override the filtering has been added
Enhanced documentation
diagnostics upgraded to version 1.15
Documentation typo fix
Digest upgraded to version 1.14
The constructor now knows which module implements SHA-224
Documentation tweaks and typo fixes
Digest::MD5 upgraded to version 2.36
XSLoader is now used for faster loading
Enhanced documentation including MD5 weaknesses discovered lately
Dumpvalue upgraded to version 1.12
Documentation fix
DynaLoader upgraded but unfortunately we're not able to increment its version number :-(
Implements dl_unload_file on Win32
Internal cleanup
XSLoader 0.06 incorporated; small optimisation for calling bootstrap_inherit() and documentation enhancements.
Encode upgraded to version 2.12
A coderef is now acceptable for CHECK!
3 new characters added to the ISO-8859-7 encoding
New encoding MIME-Header-ISO_2022_JP added
Problem with partial characters and encoding(utf-8-strict) fixed.
Documentation enhancements and typo fixes
English upgraded to version 1.02
the $COMPILING variable has been added
ExtUtils::Constant upgraded to version 0.17
Improved compatibility with older versions of perl
ExtUtils::MakeMaker upgraded to version 6.30 (was 6.17)
Too much to list here; see <http://search.cpan.org/src/MSCHWERN/ExtUtils-MakeMaker-6.30/Changes>
File::Basename upgraded to version 2.74, with changes contributed by Michael Schwern.
Documentation clarified and errors corrected.
basename now strips trailing path separators before processing the name.
basename now returns / for parameter /, to make basename consistent with the shell utility of the same name.
The suffix is no longer stripped if it is identical to the remaining characters in the name, again for consistency with the shell utility.
Some internal code cleanup.
File::Copy upgraded to version 2.09
Copying a file onto itself used to fail.
Moving a file between file systems now preserves the access and modification time stamps
File::Find upgraded to version 1.10
Win32 portability fixes
Enhanced documentation
File::Glob upgraded to version 1.05
Internal cleanup
File::Path upgraded to version 1.08
mkpath now preserves errno when mkdir fails
File::Spec upgraded to version 3.12
File::Spec-rootdir()> now returns \ on Win32, instead of /
$^O could sometimes become tainted. This has been fixed.
canonpath on Win32 now collapses foo/.. (or foo\..) sections correctly, rather than doing the misguided work it was previously doing. Note that canonpath on Unix still does not collapse these sections, as doing so would be incorrect.
Some documentation improvements
Some internal code cleanup
FileCache upgraded to version 1.06
POD formatting errors in the documentation fixed
Filter::Simple upgraded to version 0.82
FindBin upgraded to version 1.47
Now works better with directories where access rights are more restrictive than usual.
GDBM_File upgraded to version 1.08
Internal cleanup
Getopt::Long upgraded to version 2.35
prefix_pattern has now been complemented by a new configuration option long_prefix_pattern that allows the user to specify what prefix patterns should have long option style semantics applied.
Options can now take multiple values at once (experimental)
Various bug fixes
if upgraded to version 0.05
Give more meaningful error messages from if when invoked with a condition in list context.
Restore backwards compatibility with earlier versions of perl
IO upgraded to version 1.22
Enhanced documentation
Internal cleanup
IPC::Open2 upgraded to version 1.02
Enhanced documentation
IPC::Open3 upgraded to version 1.02
Enhanced documentation
List::Util upgraded to version 1.18 (was 1.14)
Fix pure-perl version of refaddr to avoid blessing an un-blessed reference
Use XSLoader for faster loading
Fixed various memory leaks
Internal cleanup and portability fixes
Math::Complex upgraded to version 1.35
atan2(0, i) now works, as do all the (computable) complex argument cases
Fixes for certain bugs in make and emake
Support returning the kth root directly
Support [2,-3pi/8] in emake
Support inf for make/emake
Document make/emake more visibly
Math::Trig upgraded to version 1.03
Add more great circle routines: great_circle_waypoint and great_circle_destination
MIME::Base64 upgraded to version 3.07
Use XSLoader for faster loading
Enhanced documentation
Internal cleanup
NDBM_File upgraded to version 1.06
Enhanced documentation
ODBM_File upgraded to version 1.06
Documentation typo fixed
Internal cleanup
Opcode upgraded to version 1.06
Enhanced documentation
Internal cleanup
open upgraded to version 1.05
Enhanced documentation
overload upgraded to version 1.04
Enhanced documentation
PerlIO upgraded to version 1.04
PerlIO::via iterate over layers properly now
PerlIO::scalar understands $/ = "" now
encoding(utf-8-strict) with partial characters now works
Enhanced documentation
Internal cleanup
Pod::Functions upgraded to version 1.03
Documentation typos fixed
Pod::Html upgraded to version 1.0504
HTML output will now correctly link to =items on the same page, and should be valid XHTML.
Variable names are recognized as intended
Documentation typos fixed
Pod::Parser upgraded to version 1.32
Allow files that start with =head on the first line
Win32 portability fix
Exit status of pod2usage fixed
New -noperldoc switch for pod2usage
Arbitrary URL schemes now allowed
Documentation typos fixed
POSIX upgraded to version 1.09
Documentation typos fixed
Internal cleanup
re upgraded to version 0.05
Documentation typo fixed
Safe upgraded to version 2.12
Minor documentation enhancement
SDBM_File upgraded to version 1.05
Documentation typo fixed
Internal cleanup
Socket upgraded to version 1.78
Internal cleanup
Storable upgraded to version 2.15
This includes the STORABLE_attach hook functionality added by Adam Kennedy, and more frugal memory requirements when storing under ithreads, by using the ithreads cloning tracking code.
Switch upgraded to version 2.10_01
Documentation typos fixed
Sys::Syslog upgraded to version 0.13
Now provides numeric macros and meaningful Exporter tags.
No longer uses Sys::Hostname as it may provide useless values in unconfigured network environments, so instead uses INADDR_LOOPBACK directly.
syslog() now uses local timestamp.
setlogmask() now behaves like its C counterpart.
setlogsock() will now croak() as documented.
Improved error and warnings messages.
Improved documentation.
Term::ANSIColor upgraded to version 1.10
Fixes a bug in colored when $EACHLINE is set that caused it to not color lines consisting solely of 0 (literal zero).
Improved tests.
Term::ReadLine upgraded to version 1.02
Documentation tweaks
Test::Harness upgraded to version 2.56 (was 2.48)
The Test::Harness timer is now off by default.
Now shows elapsed time in milliseconds.
Various bug fixes
Test::Simple upgraded to version 0.62 (was 0.54)
is_deeply() no longer fails to work for many cases
Various minor bug fixes
Documentation enhancements
Text::Tabs upgraded to version 2005.0824
Provides a faster implementation of expand
Text::Wrap upgraded to version 2005.082401
Adds $Text::Wrap::separator2, which allows you to preserve existing newlines but add line-breaks with some other string.
threads upgraded to version 1.07
threads will now honour no warnings threads
A thread's interpreter is now freed after $t->join() rather than after undef $t, which should fix some ithreads memory leaks. (Fixed by Dave Mitchell)
Some documentation typo fixes.
threads::shared upgraded to version 0.94
Documentation changes only
Note: An improved implementation of threads::shared is available on CPAN - this will be merged into 5.8.9 if it proves stable.
Tie::Hash upgraded to version 1.02
Documentation typo fixed
Time::HiRes upgraded to version 1.86 (was 1.66)
clock_nanosleep() and clock() functions added
Support for the POSIX clock_gettime() and clock_getres() has been added
Return undef or an empty list if the C gettimeofday() function fails
Improved nanosleep detection
Internal cleanup
Enhanced documentation
Unicode::Collate upgraded to version 0.52
Now implements UCA Revision 14 (based on Unicode 4.1.0).
Unicode::Collate-new> method no longer overwrites user's $_
Enhanced documentation
Unicode::UCD upgraded to version 0.24
Documentation typos fixed
User::grent upgraded to version 1.01
Documentation typo fixed
utf8 upgraded to version 1.06
Documentation typos fixed
vmsish upgraded to version 1.02
Documentation typos fixed
warnings upgraded to version 1.05
Gentler messing with Carp:: internals
Internal cleanup
Documentation update
Win32 upgraded to version 0.2601
Provides Windows Vista support to Win32::GetOSName
Documentation enhancements
XS::Typemap upgraded to version 0.02
Internal cleanup

Utility Changes


h2xs enhancements

h2xs implements new option --use-xsloader to force use of XSLoader even in backwards compatible modules.

The handling of authors' names that had apostrophes has been fixed.

Any enums with negative values are now skipped.  

perlivp enhancements

perlivp implements new option -a and will not check for *.ph files by default any more. Use the -a option to run all tests.  

New Documentation

The perlglossary manpage is a glossary of terms used in the Perl documentation, technical and otherwise, kindly provided by O'Reilly Media, inc.  

Performance Enhancements

Weak reference creation is now O(1) rather than O(n), courtesy of Nicholas Clark. Weak reference deletion remains O(n), but if deletion only happens at program exit, it may be skipped completely.
Salvador Fandino provided improvements to reduce the memory usage of sort and to speed up some cases.
Jarkko Hietaniemi and Andy Lester worked to mark as much data as possible in the C source files as static, to increase the proportion of the executable file that the operating system can share between process, and thus reduce real memory usage on multi-user systems.

Installation and Configuration Improvements

Parallel makes should work properly now, although there may still be problems if make test is instructed to run in parallel.

Building with Borland's compilers on Win32 should work more smoothly. In particular Steve Hay has worked to side step many warnings emitted by their compilers and at least one C compiler internal error.

Configure will now detect clearenv and unsetenv, thanks to a patch from Alan Burlison. It will also probe for futimes and whether sprintf correctly returns the length of the formatted string, which will both be used in perl 5.8.9.

There are improved hints for next-3.0, vmesa, IX, Darwin, Solaris, Linux, DEC/OSF, HP-UX and MPE/iX

Perl extensions on Windows now can be statically built into the Perl DLL, thanks to a work by Vadim Konovalov. (This improvement was actually in 5.8.7, but was accidentally omitted from perl587delta).  

Selected Bug Fixes


no warnings 'category' works correctly with -w

Previously when running with warnings enabled globally via -w, selective disabling of specific warning categories would actually turn off all warnings. This is now fixed; now no warnings io; will only turn off warnings in the io class. Previously it would erroneously turn off all warnings.

This bug fix may cause some programs to start correctly issuing warnings.  

Remove over-optimisation

Perl 5.8.4 introduced a change so that assignments of undef to a scalar, or of an empty list to an array or a hash, were optimised away. As this could cause problems when goto jumps were involved, this change has been backed out.  

sprintf() fixes

Using the sprintf() function with some formats could lead to a buffer overflow in some specific cases. This has been fixed, along with several other bugs, notably in bounds checking.

In related fixes, it was possible for badly written code that did not follow the documentation of Sys::Syslog to have formatting vulnerabilities. Sys::Syslog has been changed to protect people from poor quality third party code.  

Debugger and Unicode slowdown

It had been reported that running under perl's debugger when processing Unicode data could cause unexpectedly large slowdowns. The most likely cause of this was identified and fixed by Nicholas Clark.  

Smaller fixes

FindBin now works better with directories where access rights are more restrictive than usual.
Several memory leaks in ithreads were closed. An improved implementation of threads::shared is available on CPAN - this will be merged into 5.8.9 if it proves stable.
Trailing spaces are now trimmed from $! and $^E.
Operations that require perl to read a process' list of groups, such as reads of $( and $), now dynamically allocate memory rather than using a fixed sized array. The fixed size array could cause C stack exhaustion on systems configured to use large numbers of groups.
PerlIO::scalar now works better with non-default $/ settings.
You can now use the x operator to repeat a qw// list. This used to raise a syntax error.
The debugger now traces correctly execution in eval("")uated code that contains #line directives.
The value of the open pragma is no longer ignored for three-argument opens.
The optimisation of for (reverse @a) introduced in perl 5.8.6 could misbehave when the array had undefined elements and was used in LVALUE context. Dave Mitchell provided a fix.
Some case insensitive matches between UTF-8 encoded data and 8 bit regexps, and vice versa, could give malformed character warnings. These have been fixed by Dave Mitchell and Yves Orton.
lcfirst and ucfirst could corrupt the string for certain cases where the length UTF-8 encoding of the string in lower case, upper case or title case differed. This was fixed by Nicholas Clark.
Perl will now use the C library calls unsetenv and clearenv if present to delete keys from %ENV and delete %ENV entirely, thanks to a patch from Alan Burlison.

New or Changed Diagnostics


Attempt to set length of freed array

This is a new warning, produced in situations such as this:

$r = do {my @a; \$#a}; $$r = 503;  

Non-string passed as bitmask

This is a new warning, produced when number has been passed as a argument to select(), instead of a bitmask.

# Wrong, will now warn $rin = fileno(STDIN); ($nfound,$timeleft) = select($rout=$rin, undef, undef, $timeout); # Should be $rin = ; vec($rin,fileno(STDIN),1) = 1; ($nfound,$timeleft) = select($rout=$rin, undef, undef, $timeout);  

Search pattern not terminated or ternary operator parsed as search pattern

This syntax error indicates that the lexer couldn't find the final delimiter of a ?PATTERN? construct. Mentioning the ternary operator in this error message makes it easier to diagnose syntax errors.  

Changed Internals

There has been a fair amount of refactoring of the C source code, partly to make it tidier and more maintainable. The resulting object code and the perl binary may well be smaller than 5.8.7, in particular due to a change contributed by Dave Mitchell which reworked the warnings code to be significantly smaller. Apart from being smaller and possibly faster, there should be no user-detectable changes.

Andy Lester supplied many improvements to determine which function parameters and local variables could actually be declared const to the C compiler. Steve Peters provided new *_set macros and reworked the core to use these rather than assigning to macros in LVALUE context.

Dave Mitchell improved the lexer debugging output under -DT

Nicholas Clark changed the string buffer allocation so that it is now rounded up to the next multiple of 4 (or 8 on platforms with 64 bit pointers). This should reduce the number of calls to realloc without actually using any extra memory.

The HV's array of HE*s is now allocated at the correct (minimal) size, thanks to another change by Nicholas Clark. Compile with -DPERL_USE_LARGE_HV_ALLOC to use the old, sloppier, default.

For XS or embedding debugging purposes, if perl is compiled with -DDEBUG_LEAKING_SCALARS_FORK_DUMP in addition to -DDEBUG_LEAKING_SCALARS then a child process is forked just before global destruction, which is used to display the values of any scalars found to have leaked at the end of global destruction. Without this, the scalars have already been freed sufficiently at the point of detection that it is impossible to produce any meaningful dump of their contents. This feature was implemented by the indefatigable Nicholas Clark, based on an idea by Mike Giroux.  

Platform Specific Problems

The optimiser on HP-UX 11.23 (Itanium 2) is currently partly disabled (scaled down to +O1) when using HP C-ANSI-C; the cause of problems at higher optimisation levels is still unclear.

There are a handful of remaining test failures on VMS, mostly due to test fixes and minor module tweaks with too many dependencies to integrate into this release from the development stream, where they have all been corrected. The following is a list of expected failures with the patch number of the fix where that is known:

ext/Devel/PPPort/t/ppphtest.t #26913 ext/List/Util/t/p_tainted.t #26912 lib/ExtUtils/t/PL_FILES.t #26813 lib/ExtUtils/t/basic.t #26813 t/io/fs.t t/op/cmp.t  

Reporting Bugs

If you find what you think is a bug, you might check the articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at http://bugs.perl.org. There may also be information at http://www.perl.org, the Perl Home Page.

If you believe you have an unreported bug, please run the perlbug program included with your release. Be sure to trim your bug down to a tiny but sufficient test case. Your bug report, along with the output of perl -V, will be sent off to perlbug@perl.org to be analysed by the Perl porting team. You can browse and search the Perl 5 bugs at http://bugs.perl.org/  


The Changes file for exhaustive details on what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.



Incompatible Changes
Core Enhancements
Modules and Pragmata
Utility Changes
h2xs enhancements
perlivp enhancements
New Documentation
Performance Enhancements
Installation and Configuration Improvements
Selected Bug Fixes
no warnings 'category' works correctly with -w
Remove over-optimisation
sprintf() fixes
Debugger and Unicode slowdown
Smaller fixes
New or Changed Diagnostics
Attempt to set length of freed array
Non-string passed as bitmask
Search pattern not terminated or ternary operator parsed as search pattern
Changed Internals
Platform Specific Problems
Reporting Bugs

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