=head2 Perl Source Incompatibilities
-Beware that any new warnings that have been added are B<not> considered
-incompatible changes.
+Beware that any new warnings that have been added or enhanced old
+warnings are B<not> considered incompatible changes.
Since all new warnings must be explicitly requested via the C<-w>
switch or the C<warnings> pragma, it is ultimately the programmer's
rand(3) function. As of 5.005_52, Configure tests for drand48(),
random(), and rand() (in that order) and picks the first one it finds.
Perl programs that depend on reproducing a specific set of pseudo-random
-numbers will now likely produce different output.
+numbers will now likely produce different output. You can use
+C<sh Configure -Drandfunc=rand> to obtain the old behavior.
=item Hashing function for hash keys has changed
each(), values() and hashes in a list context return the actual
values in the hash, instead of copies (as they used to in earlier
versions). Typical idioms for using these constructs copy the
-returned values, but this is can make a significant difference when
+returned values, but this can make a significant difference when
creating references to the returned values.
Keys in the hash are still returned as copies when iterating on
Note that these functions do B<not> constitute Perl's memory allocation API.
See L<perlguts/"Memory Allocation"> for further information about that.
-=item C<PL_na> and C<dTHR> Issues
-
-The C<PL_na> global is now thread local, so a C<dTHR> declaration is needed
-in the scope in which the global appears. XSUBs should handle this automatically,
-but if you have used C<PL_na> in support functions, you either need to
-change the C<PL_na> to a local variable (which is recommended), or put in
-a C<dTHR>.
-
=back
=head2 Compatible C Source API Changes
=head2 Long Doubles
Some platforms have "long doubles", floating point numbers of even
-larger range than ordinary "doubles". To enable using ng doubles for
+larger range than ordinary "doubles". To enable using long doubles for
Perl's scalars, use -Duselongdouble.
=head2 -Dusemorebits
=head2 SOCKS support
You can use "Configure -Dusesocks" which causes Perl to probe
-for the SOCKS proxy protocol library, http://www.socks.nec.com/
+for the SOCKS (v5, not v4) proxy protocol library,
+http://www.socks.nec.com/
=head2 C<-A> flag
hints files have been processed but before the actual configuration
process starts. Run C<Configure -h> to find out the full C<-A> syntax.
-=head2 New Installation Scheme
+=head2 Enhanced Installation Directories
-vendorprefix et al
-[TODO - Andy Dougherty <doughera@lafcol.lafayette.edu>]
+The installation structure has been enriched to improve the support for
+maintaining multiple versions of perl, to provide locations for
+vendor-supplied modules and scripts, and to ease maintenance of
+locally-added modules and scripts. See the section on Installation
+Directories in the INSTALL file for complete details. For most users
+building and installing from source, the defaults should be fine.
=head1 Core Changes
included with the standard Perl distribution) may also be of use, it
offers the getrlimit/setrlimit interface that can be used to adjust
process resource usage limits, including the maximum filesize limit.
-
+
=head2 Long doubles
In some systems you may be able to use long doubles to enhance the
since the exec() happened to be in a different process.
The child process now communicates with the parent about the
-error in launching the external command, which allow these
+error in launching the external command, which allows these
constructs to return with their usual error value and set $!.
=head2 Implicitly closed filehandles are safer
=head2 Locale bugs fixed
-printf() and sprintf() previously did reset the numeric locale
+printf() and sprintf() previously reset the numeric locale
back to the default "C" locale. This has been fixed.
Numbers formatted according to the local numeric locale
is used.
Note that something resembling the previous behavior can still be
-obtained by putting C<BEGIN { $^C = 0; exit; } at the very end of
+obtained by putting C<BEGIN { $^C = 0; exit; }> at the very end of
the top level source file.
=head2 Potential to leak DATA filehandles
=head2 Other fixes for better diagnostics
-Line numbers are suppressed no more (under most likely circumstances)
+Line numbers are no longer suppressed (under most likely circumstances)
during the global destruction phase.
Diagnostics emitted from code running in threads other than the main
$foo::a and $foo::b are now exempt from "possible typo" warnings only
if sort() is encountered in package foo.
-Unrecognized alphabetic escapes encountered when parsing quoting
+Unrecognized alphabetic escapes encountered when parsing quote
constructs now generate a warning, since they may take on new
semantics in later versions of Perl.
=item B
+The Perl Compiler suite has been extensively reworked for this
+release.
+
[TODO - Vishal Bhatia <vishal@gol.com>,
Nick Ing-Simmons <nick@ni-s.u-net.com>]
The ByteLoader is a dedicated extension to generate and run
Perl bytecode. See L<ByteLoader>.
-=item B
-
-The Perl Compiler suite has been extensively reworked for this
-release.
-
=item constant
References can now be used. See L<constant>.
=item Data::Dumper
A C<Maxdepth> setting can be specified to avoid venturing
-too deeply into data structures that may be very deep.
-See L<Data::Dumper>.
+too deeply into deep data structures. See L<Data::Dumper>.
Dumping C<qr//> objects works correctly.
=item Devel::DProf
-Devel::DProf, a Perl source code profiler has been added. See L<DProf>.
+Devel::DProf, a Perl source code profiler has been added. See
+L<Devel::DProf> and L<dprofpp>.
=item Dumpvalue
-Added Dumpvalue module provides screen dumps of Perl data.
+The Dumpvalue module provides screen dumps of Perl data.
=item Benchmark
+Overall, Benchmark results exhibit lower average error and better timing
+accuracy.
+
You can now run tests for I<n> seconds instead of guessing the right
number of tests to run: e.g. timethese(-5, ...) will run each
code for at least 5 CPU seconds. Zero as the "number of repetitions"
means "for at least 3 CPU seconds". The output format has also
changed. For example:
-use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
+ use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
will now output something like this:
-Benchmark: running a, b, each for at least 5 CPU seconds...
- a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
- b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
+ Benchmark: running a, b, each for at least 5 CPU seconds...
+ a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
+ b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
New features: "each for at least N CPU seconds...", "wallclock secs",
and the "@ operations/CPU second (n=operations)".
-change#4265,4266,4292
-[TODO - Barrie Slaymaker <barries@slaysys.com>]
+timethese() now returns a reference to a hash of Benchmark objects containing
+the test results, keyed on the names of the tests.
+
+timethis() now returns the iterations field in the Benchmark result object
+instead of 0.
+
+timethese(), timethis(), and the new cmpthese() (see below) can also take
+a format specifier of 'none' to suppress output.
+
+A new function countit() is just like timeit() except that it takes a
+TIME instead of a COUNT.
+
+A new function cmpthese() prints a chart comparing the results of each test
+returned from a timethese() call. For each possible pair of tests, the
+percentage speed difference (iters/sec or seconds/iter) is shown.
+
+For other details, see L<Benchmark>.
=item Devel::Peek
=item Getopt::Long
-[TODO - Johan Vromans <jvromans@squirrel.nl>]
+Getopt::Long licensing has changed to allow the Perl Artistic License
+as well as the GPL. It used to be GPL only, which got in the way of
+non-GPL applications that wanted to use Getopt::Long.
+
+Getopt::Long encourages the use of Pod::Usage to produce help
+messages. For example:
+
+ use Getopt::Long;
+ use Pod::Usage;
+ my $man = 0;
+ my $help = 0;
+ GetOptions('help|?' => \$help, man => \$man) or pod2usage(2);
+ pod2usage(1) if $help;
+ pod2usage(-exitstatus => 0, -verbose => 2) if $man;
+
+ __END__
+
+ =head1 NAME
+
+ sample - Using GetOpt::Long and Pod::Usage
+
+ =head1 SYNOPSIS
+
+ sample [options] [file ...]
+
+ Options:
+ -help brief help message
+ -man full documentation
+
+ =head1 OPTIONS
+
+ =over 8
+
+ =item B<-help>
+
+ Print a brief help message and exits.
+
+ =item B<-man>
+
+ Prints the manual page and exits.
+
+ =back
+
+ =head1 DESCRIPTION
+
+ B<This program> will read the given input file(s) and do someting
+ useful with the contents thereof.
+
+ =cut
+
+See L<Pod::Usage> for details.
+
+A bug that prevented the non-option call-back E<lt>E<gt> from being
+specified as the first argument has been fixed.
+
+To specify the characters E<lt> and E<gt> as option starters, use
+E<gt>E<lt>. Note, however, that changing option starters is strongly
+deprecated.
=item IO
=item Math::BigInt
-The logical operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>,
+The bitwise operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>,
and C<~> are now supported on bigints.
=item Math::Complex
=item Time::Local
The timelocal() and timegm() functions used to silently return bogus
-results when the date exceeded the machine's integer range. They
+results when the date fell outside the machine's integer range. They
now consistently croak() if the date falls in an unsupported range.
=item Win32
The new Win32::GetFullPathName(FILENAME) returns the full absolute
pathname for FILENAME in scalar context. In list context it returns
a two-element list containing the fully qualified directory name and
-the filename.
+the filename. See L<Win32>.
=item DBM Filters
=head2 Pragmata
-C<use attrs> is now obsolescent, and is only provided for
+C<use attrs> is now obsolete, and is only provided for
backward-compatibility. It's been replaced by the C<sub : attributes>
syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>.
An introduction to using the Perl Compiler suite.
+=item perlfilter.pod
+
+An introduction to writing Perl source filters.
+
=item perlhack.pod
Some guidelines for hacking the Perl source code.
=back
-=head1 New Diagnostics
+=head1 New or Changed Diagnostics
=over 4
=item / must be followed by a*, A* or Z*
-(F) You had an pack template indicating a counted-length string,
+(F) You had a pack template indicating a counted-length string,
Currently the only things that can have their length counted are a*, A* or Z*.
See L<perlfunc/pack>.
but this did not follow some numeric unpack specification.
See L<perlfunc/pack>.
-=item Repeat count in pack overflows
-
-(F) You can't specify a repeat count so large that it overflows
-your signed integers. See L<perlfunc/pack>.
-
-=item Repeat count in unpack overflows
-
-(F) You can't specify a repeat count so large that it overflows
-your signed integers. See L<perlfunc/unpack>.
-
=item /%s/: Unrecognized escape \\%c passed through
(W) You used a backslash-character combination which is not recognized
by Perl. This combination appears in an interpolated variable or a
-C<'>-delimited regular expression.
+C<'>-delimited regular expression. The character was understood literally.
+
+=item /%s/: Unrecognized escape \\%c in character class passed through
+
+(W) You used a backslash-character combination which is not recognized
+by Perl inside character classes. The character was understood literally.
=item /%s/ should probably be written as "%s"
(W) You have used a pattern where Perl expected to find a string,
-like in the first argument to C<join>. Perl will treat the true
+as in the first argument to C<join>. Perl will treat the true
or false result of matching the pattern against $_ as the string,
which is probably not what you had in mind.
(P) For some reason you can't check the filesystem of the script for nosuid.
+=item Can't ignore signal CHLD, forcing to default
+
+(W) Perl has detected that it is being run with the SIGCHLD signal
+(sometimes known as SIGCLD) disabled. Since disabling this signal
+will interfere with proper determination of exit status of child
+processes, Perl has reset the signal to its default value.
+This situation typically indicates that the parent program under
+which Perl may be running (e.g. cron) is being very careless.
+
=item Can't modify non-lvalue subroutine call
-(F) Subroutines used in lvalue context should be marked as such, see
-L<perlsub/"Lvalue subroutines">.
+(F) Subroutines meant to be used in lvalue context should be declared as
+such, see L<perlsub/"Lvalue subroutines">.
=item Can't read CRTL environ
=item Character class [:%s:] unknown
(F) The class in the character class [: :] syntax is unknown.
+See L<perlre>.
=item Character class syntax [%s] belongs inside character classes
(W) The character class constructs [: :], [= =], and [. .] go
I<inside> character classes, the [] are part of the construct,
-for example: /[012[:alpha:]345]/. Note that the last two constructs
-are not currently implemented, they are placeholders for future extensions.
+for example: /[012[:alpha:]345]/. Note that [= =] and [. .]
+are not currently implemented; they are simply placeholders for
+future extensions.
=item Constant is not %s reference
(F) While under the C<use filetest> pragma, switching the real and
effective uids or gids failed.
+=item false [] range "%s" in regexp
+
+(W) A character class range must start and end at a literal character, not
+another character class like C<\d> or C<[:alpha:]>. The "-" in your false
+range is interpreted as a literal "-". Consider quoting the "-", "\-".
+See L<perlre>.
+
=item Filehandle %s opened only for output
(W) You tried to read from a filehandle opened only for writing. If you
-intended it to be a read-write filehandle, you needed to open it with
+intended it to be a read/write filehandle, you needed to open it with
"+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If
you intended only to read from the file, use "E<lt>". See
L<perlfunc/open>.
=item Illegal binary digit %s
-(F) You used a digit other than 0 and 1 in a binary number.
+(F) You used a digit other than 0 or 1 in a binary number.
=item Illegal binary digit %s ignored
=item Integer overflow in %s number
(W) The hexadecimal, octal or binary number you have specified either
-as a literal in your code or as a scalar is too big for your
+as a literal or as an argument to hex() or oct() is too big for your
architecture, and has been converted to a floating point number. On a
32-bit architecture the largest hexadecimal, octal or binary number
representable without overflow is 0xFFFFFFFF, 037777777777, or
The indicated attributes for a subroutine or variable were not recognized
by Perl or by a user-supplied handler. See L<attributes>.
+=item invalid [] range "%s" in regexp
+
+The offending range is now explicitly displayed.
+
=item Invalid separator character %s in attribute list
(F) Something other than a comma or whitespace was seen between the
See Server error.
+=item Repeat count in pack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/pack>.
+
+=item Repeat count in unpack overflows
+
+(F) You can't specify a repeat count so large that it overflows
+your signed integers. See L<perlfunc/unpack>.
+
=item realloc() of freed memory ignored
(S) An internal routine called realloc() on something that had already
(F) While under the C<use filetest> pragma, we cannot switch the
real and effective uids or gids.
-=item This Perl can't reset CRTL eviron elements (%s)
+=item This Perl can't reset CRTL environ elements (%s)
=item This Perl can't set CRTL environ elements (%s=%s)
=item Unknown open() mode '%s'
-(F) The second argument of 3-arguments open is not one from the list
-of C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>, C<+L<gt>>,
-C<+E<gt>E<gt>>, C<-|>, C<|-> of possible open() modes.
+(F) The second argument of 3-argument open() is not among the list
+of valid modes: C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>,
+C<+L<gt>>, C<+E<gt>E<gt>>, C<-|>, C<|->.
=item Unknown process %x sent message to prime_env_iter: %s
=item Unrecognized escape \\%c passed through
(W) You used a backslash-character combination which is not recognized
-by Perl.
+by Perl. The character was understood literally.
=item Unterminated attribute parameter in attribute list
=head1 BUGS
-If you find what you think is a bug, you might check the headers of
+If you find what you think is a bug, you might check the
articles recently posted to the comp.lang.perl.misc newsgroup.
There may also be information at http://www.perl.com/perl/, the Perl
Home Page.