perldelta - what's new for perl5.005
This document describes differences between the 5.004 release and this one.
Perl is now developed on two tracks: a maintenance track that makes small,
safe updates to released production versions with emphasis on
compatibility; and a development track that pursues more aggressive
evolution. Maintenance releases (which should be considered production
quality) have subversion numbers that run from 1 to 49, and development releases (which should be considered ``alpha'' quality)
run from 50 to 99.
Perl 5.005 is the combined product of the new dual-track development scheme.
Starting with Perl 5.004_50 there were many deep and far-reaching changes to the language internals. If you have dynamically loaded extensions that you built under perl 5.003 or 5.004, you can continue to use them with 5.004, but you will need to rebuild and reinstall those extensions to use them 5.005. See INSTALL for detailed instructions on how to upgrade.
The new Configure defaults are designed to allow a smooth upgrade from 5.004 to 5.005, but you should read INSTALL for a detailed discussion of the changes in order to adapt them to your system.
When none of the experimental features are enabled, there should be very few user-visible Perl source compatibility issues.
If threads are enabled, then some caveats apply. @_ and $_ become lexical variables. The effect of this should be largely transparent
to the user, but there are some boundary conditions under which user will
need to be aware of the issues. For example, local(@_) results in a ``Can't localize lexical variable @_ ...''
message. This may be enabled in a future version.
Some new keywords have been introduced. These are generally expected to
have very little impact on compatibility. See New
Certain barewords are now reserved. Use of these will provoke a warning if
you have asked for them with the
There have been a large number of changes in the internals to support the
new features in this release.
An ANSI C compiler is now required to build perl. See INSTALL.
All Perl global variables that are visible for use by extensions now have a
If you find that your XS extension does not compile anymore because a perl
global is not visible, try adding a
It is strongly recommended that all functions in the Perl API that don't
begin with perl be referenced with a
See API LISTING.
Perl built with threading enabled requires extensions to use the new
The API function
See C Source Compatibility for more information.
This version is NOT binary compatible with older versions. All extensions
will need to be recompiled. Further binaries built with threads enabled are
incompatible with binaries built without. This should largely be
transparent to the user, as all binary incompatible configurations have
their own unique architecture name, and extension binaries get installed at
unique locations. This allows coexistence of several configurations in the
same directory hierarchy. See INSTALL.
A few taint leaks and taint omissions have been corrected. This may lead to
``failure'' of scripts that used to work with older versions. Compiling
with -DINCOMPLETE_TAINTS provides a perl with minimal amounts of changes to
the tainting behavior. But note that the resulting perl will have known
insecurities.
Oneliners with the
Many new warnings that were introduced in 5.004 have been made optional.
Some of these warnings are still present, but perl's new features make them
less often a problem. See New Diagnostics.
Perl has a new Social Contract for contributors. See Porting/Contract.
The license included in much of the Perl documentation has changed. Most of
the Perl documentation was previously under the implicit GNU General Public
License or the Artistic License (at the user's choice). Now much of the
documentation unambigously states the terms under which it may be
distributed. Those terms are in general much less restrictive than the GNU
GPL. See the perl manpage and the individual perl man pages listed therein.
WARNING: Threading is considered an experimental feature. Details of the implementation may change without notice. There are
known limitations and some bugs. These are expected to be fixed in future
versions.
See README.threads.
Mach cthreads (NEXTSTEP, OPENSTEP, Rhapsody) are now supported by the
Thread extension.
WARNING: The Compiler and related tools are considered experimental. Features may change without notice, and there are known limitations and
bugs. Since the compiler is fully external to perl, the default
configuration will build and install it.
The Compiler produces three different types of transformations of a perl
program. The C backend generates C code that captures perl's state just
before execution begins. It eliminates the compile-time overheads of the
regular perl interpreter, but the run-time performance remains
comparatively the same. The CC backend generates optimized C code
equivalent to the code path at run-time. The CC backend has greater
potential for big optimizations, but only a few optimizations are
implemented currently. The Bytecode backend generates a platform
independent bytecode representation of the interpreter's state just before
execution. Thus, the Bytecode back end also eliminates much of the
compilation overhead of the interpreter.
The compiler comes with several valuable utilities.
See
Perl's regular expression engine has been seriously overhauled, and many
new constructs are supported. Several bugs have been fixed.
Here is an itemized summary:
Changes in the RE engine:
Changes in Perl code using RE engine:
Note that only the major bug fixes are listed here. See Changes for others.
The following new syntax elements are supported:
See New C
See the perlre manpage and the perlop manpage.
See banner at the beginning of
Perl now contains its own highly optimized
See
Perl's signal handling is susceptible to random crashes, because signals
arrive asynchronously, and the Perl runtime is not reentrant at arbitrary
times.
However, one experimental implementation of reliable signals is available
when threads are enabled. See
The internals now reallocate the perl stack only at predictable times. In
particular, magic calls never trigger reallocations of the stack, because
all reentrancy of the runtime is handled using a ``stack of stacks''. This
should improve reliability of cached stack pointers in the internals and in
XSUBs.
Perl used to complain if it encountered literal carriage returns in
scripts. Now they are mostly treated like whitespace within program text.
Inside string literals and here documents, literal carriage returns are
ignored if they occur paired with linefeeds, or get interpreted as
whitespace if they stand alone. This behavior means that literal carriage
returns in files should be avoided. You can get the older, more compatible
(but less generous) behavior by defining the preprocessor symbol
Note that this doesn't somehow magically allow you to keep all text files
in DOS format. The generous treatment only applies to files that perl
itself parses. If your C compiler doesn't allow carriage returns in files,
you may still be unable to build modules that need a C compiler.
The build-time option
See Temporary Values via local().
See the perlvar manpage, and the Errno manpage.
See the perlref manpage.
See the perlsyn manpage.
See the perlsub manpage.
See the perlvar manpage.
Barewords caused unintuitive behavior when a subroutine with the same name
as a package happened to be defined. Thus,
It was impossible to test for the existence of a package without actually
creating it before. Now
Perl5 has always had 64-bit support on systems with 64-bit longs. Starting
with 5.005, the beginnings of experimental support for systems with 32-bit
long and 64-bit 'long long' integers has been added. If you add
-DUSE_LONG_LONG to your ccflags in config.sh (or manually define it in
perl.h) then perl will be built with 'long long' support. There will be
many compiler warnings, and the resultant perl may not work on all systems.
There are many other issues related to third-party extensions and
libraries. This option exists to allow people to work on those issues.
See prototype.
See Destructors.
See printf.
The
To minimize impact on source compatibility this keyword is ``weak'', i.e.,
any user-defined subroutine of the same name overrides it, unless a
The
Calling a subroutine with the name
See Tie::Array.
Several missing hooks have been added. There is also a new base class for
TIEARRAY implementations. See Tie::Array.
When you say something like
In previous versions, this would print ``hello'', but it now prints
``g'bye''.
If
The new format type 'Z' is useful for packing and unpacking null-terminated
strings. See pack.
With
This means that the following will append ``foo'' to an empty file (it used
to not do anything before):
Note that the behavior of:
is unchanged (it continues to leave the file empty).
Configure has many incremental improvements. Site-wide policy for building
perl can now be made persistent, via Policy.sh. Configure also records the
command-line arguments used in config.sh.
BeOS is now supported. See README.beos.
DOS is now supported under the DJGPP tools. See README.dos.
GNU/Hurd is now supported.
MiNT is now supported. See README.mint.
MPE/iX is now supported. See README.mpeix.
MVS (aka OS390, aka Open Edition) is now supported. See README.os390.
Stratus VOS is now supported. See README.vos.
Win32 support has been vastly enhanced. Support for Perl Object, a C++
encapsulation of Perl. GCC and EGCS are now supported on Win32. See README.win32, aka perlwin32.
VMS configuration system has been rewritten. See README.vms.
The hints files for most Unix platforms have seen incremental improvements.
Perl compiler and tools. See the B manpage.
A module to pretty print Perl data. See Data::Dumper.
A module to dump perl values to the screen. See the Dumpvalue manpage.
A module to look up errors more conveniently. See the Errno manpage.
A portable API for file operations.
Query and manage installed modules.
Manipulate .packlist files.
Make functions/builtins succeed or die.
Constants and other support infrastructure for System V IPC operations in
perl.
A framework for writing testsuites.
Base class for tied arrays.
Base class for tied handles.
Perl thread creation, manipulation, and support.
Set subroutine attributes.
Compile-time class fields.
Various pragmata to control behavior of regular expressions.
You can now run tests for n seconds instead of guessing the right number of tests to run: e.g.
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)
New features: ``each for at least N CPU seconds...'', ``wallclock secs'',
and the ``@ operations/CPU second (n=operations)''.
Carp has a new function
CGI has been updated to version 2.42.
More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for large
(more than 4G) file access (the 64-bit support is not yet working, though,
so no need to get overly excited), Free/Net/OpenBSD locking behaviour flags
F_FLOCK, F_POSIX, Linux F_SHLCK, and O_ACCMODE: the mask of O_RDONLY,
O_WRONLY, and O_RDWR.
The accessor methods Re, Im, arg, abs, rho, and theta, can now also act as
mutators (accessor $z->Re(), mutator $z->Re(3)).
A little bit of radial trigonometry (cylindrical and spherical) added:
radial coordinate conversions and the great circle distance.
POSIX now has its own platform-specific hints files.
DB_File supports version 2.x of Berkeley DB. See
MakeMaker now supports writing empty makefiles, provides a way to specify
that site
Extensions that have both architecture-dependent and
architecture-independent files are now always installed completely in the
architecture-dependent locations. Previously, the shareable parts were
shared both across architectures and across perl versions and were
therefore liable to be overwritten with newer versions that might have
subtle incompatibilities.
See <perlmodinstall> and the CPAN manpage.
Cwd::cwd is faster on most platforms.
Keeps better time.
The crude GNU
Config.pm now has a glossary of variables.
Porting/patching.pod has detailed instructions on how to create and submit patches for perl.
the perlport manpage specifies guidelines on how to write portably.
the perlmodinstall manpage describes how to fetch and install modules from CPAN
sites.
Some more Perl traps are documented now. See the perltrap manpage.
the perlopentut manpage gives a tutorial on using
the perlreftut manpage gives a tutorial on references.
the perlthrtut manpage gives a tutorial on threads.
(W) A subroutine you have declared has the same name as a Perl keyword, and
you have used the name without qualification for calling one or the other.
Perl decided to call the builtin because the subroutine is not imported.
To force interpretation as a subroutine call, either put an ampersand
before the subroutine name, or qualify the name with its package.
Alternatively, you can import the subroutine (or pretend that it's imported
with the
To silently interpret it as the Perl operator, use the
(F) The index looked up in the hash found as the 0'th element of a
pseudo-hash is not legal. Index values must be at 1 or greater. See the perlref manpage.
(W) You used a qualified bareword of the form
(F) You used the syntax of a method call, but the slot filled by the object
reference or package name contains an undefined value. Something like this
will reproduce the error:
(P) For some reason you can't check the filesystem of the script for
nosuid.
(F) You used an array where a hash was expected, but the array has no
information on how to map from keys to array indices. You can do that only
with arrays that have a hash reference at index 0.
(F) The ``goto subroutine'' call can't be used to jump out of an eval
``string''. (You can use it to jump out of an eval {BLOCK}, but you
probably don't want to.)
(F) You said something like
(F) The first time the %! hash is used, perl automatically loads the
Errno.pm module. The Errno module is expected to tie the %! hash to provide
symbolic names for
(F) A string of a form
(W) Within regular expression character classes ([]) the syntax beginning
with ``[.'' and ending with ``.]'' is reserved for future extensions. If
you need to represent those character sequences inside a regular expression
character class, just quote the square brackets with the backslash: ``\[.''
and ``.\]''.
(W) Within regular expression character classes ([]) the syntax beginning
with ``[:'' and ending with ``:]'' is reserved for future extensions. If
you need to represent those character sequences inside a regular expression
character class, just quote the square brackets with the backslash: ``\[:''
and ``:\]''.
(W) Within regular expression character classes ([]) the syntax beginning
with ``[='' and ending with ``=]'' is reserved for future extensions. If
you need to represent those character sequences inside a regular expression
character class, just quote the square brackets with the backslash: ``\[=''
and ``=\]''.
(F) Perl detected tainted data when trying to compile a regular expression
that contains the
(F) A regular expression contained the
(F) Perl tried to compile a regular expression containing the
(W) You are blessing a reference to a zero length string. This has the
effect of blessing the reference into the package main. This is usually not
what you want. Consider providing a default target package, e.g.
(W) You may have tried to use a character other than 0 - 9 or A - F in a
hexadecimal number. Interpretation of the hexadecimal number stopped before
the illegal character.
(F) You tried to access an array as a hash, but the field name used is not
defined. The hash at index 0 should map all valid field names to array
indices for that to work.
(F) You tried to access a field of a typed variable where the type does not
know about the field name. The field names are looked up in the
(F) You can't allocate more than 2^31+``small amount'' bytes. This error is
most likely to be caused by a typo in the Perl program. e.g.,
(F) One (or both) of the numeric arguments to the range operator ``..'' are
outside the range which can be represented by integers internally. One
possible workaround is to force Perl to use magical string increment by
prepending ``0'' to your numbers.
(F) More than 100 levels of inheritance were encountered while invoking a
method. Probably indicates an unintended loop in your inheritance
hierarchy.
(W) You gave a single reference where Perl was expecting a list with an
even number of elements (for assignment to a hash). This usually means that
you used the anon hash constructor when you meant to use parens. In any
case, a hash requires key/value pairs.
(W) An undefined value was assigned to a typeglob, a la
(D) The indicated bareword is a reserved word. Future versions of perl may
use it as a keyword, so you're better off either explicitly quoting the
word in a manner appropriate for its context of use, or using a different
name altogether. The warning can be suppressed for subroutine names by
either adding a
(S) The whole warning message will look something like:
Exactly what were the failed locale settings varies. In the above the
settings were that the LC_ALL was ``En_US'' and the LANG had no value. This
error means that Perl detected that you and/or your system administrator
have set up the so-called variable system but Perl could not use those
settings. This was not dead serious, fortunately: there is a ``default
locale'' called ``C'' that Perl can and will use, the script will be run.
Before you really fix the problem, however, you will get the same error
message each time you run Perl. How to really fix the problem can be found
in LOCALE PROBLEMS.
(F) The
Removed because -e doesn't use temporary files any more.
(F) The write routine failed for some reason while trying to process a -e switch. Maybe your /tmp partition is full, or clobbered.
Removed because -e doesn't use temporary files any more.
(F) The create routine failed for some reason while trying to process a -e switch. Maybe your /tmp partition is full, or clobbered.
Removed because -e doesn't use temporary files any more.
(F) The current implementation of regular expressions uses shorts as
address offsets within a string. Unfortunately this means that if the
regular expression compiles to longer than 32767, it'll blow up. Usually
when you want a regular expression this big, there is a better way to do it
with multiple statements. See the perlre manpage.
You can use ``Configure -Uinstallusrbinperl'' which causes installperl to
skip installing perl also as /usr/bin/perl. This is useful if you prefer
not to modify /usr/bin for some reason or another but harmful because many
scripts assume to find Perl in /usr/bin/perl.
If you find what you think is a bug, you might check the headers of
recently posted articles in the comp.lang.perl.misc newsgroup. There may
also be information at http://www.perl.com/perl/, the Perl
Home Page.
If you believe you have an unreported bug, please run the perlbug
program included with your release. Make sure you trim your bug down to a
tiny but sufficient test case. Your bug report, along with the output of
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.
Written by Gurusamy Sarathy <gsar@umich.edu>, with many contributions from The Perl Porters.
Send omissions or corrections to <perlbug@perl.com>.
INIT keyword,
New lock keyword, and New C-w switch. See our is now a reserved word.
C Source Compatibility
PL_ prefix. New extensions should not refer to perl globals by their unqualified names. To preserve sanity, we
provide limited backward compatibility for globals that are being widely
used like
sv_undef and na (which should now be written as PL_sv_undef,
PL_na etc.)
PL_ prefix to the global and rebuild.
Perl_ prefix. The bare function names without the Perl_ prefix are supported with macros, but this support may cease in a future
release.
dTHR macro to initialize the handle to access per-thread data. If you see a
compiler error that talks about the variable thr not being declared (when building a module that has XS code), you need to
add dTHR; at the beginning of the block that elicited the error.
perl_get_sv("@",FALSE) should be used instead of directly accessing perl globals as GvSV(errgv). The API call is backward compatible with existing perls and provides
source compatibility with threading is enabled.
Binary Compatibility
Security fixes may affect compatibility
-e switch do not create temporary files anymore.
Relaxed new mandatory warnings introduced in 5.004
Licensing
Core Changes
Threads
Compiler
B::Lint is an experimental module to detect and warn about suspicious code,
especially the cases that the -w switch does not detect.
B::Deparse can be used to demystify perl code, and understand how perl optimizes
certain constructs.
B::Xref generates cross reference reports of all definition and use of variables,
subroutines and formats in a program.
B::Showlex show the lexical variables used by a subroutine or file at a glance.
perlcc is a simple frontend for compiling perl.
ext/B/README, the B manpage, and the respective compiler modules.
Regular Expressions
Unneeded nodes removed;
Substrings merged together;
New types of nodes to process (SUBEXPR)* and similar expressions
quickly, used if the SUBEXPR has no side effects and matches
strings of the same length;
Better optimizations by lookup for constant substrings;
Better search for constants substrings anchored by $ ;
More optimizations to s/longer/short/;
study() was not working;
/blah/ may be optimized to an analogue of index() if $& $` $' not seen;
Unneeded copying of matched-against string removed;
Only matched part of the string is copying if $` $' were not seen;
Backtracking might not restore start of $3.
No feedback if max count for * or + on "complex" subexpression
was reached, similarly (but at compile time) for {3,34567}
Primitive restrictions on max count introduced to decrease a
possibility of a segfault;
(ZERO-LENGTH)* could segfault;
(ZERO-LENGTH)* was prohibited;
Long REs were not allowed;
/RE/g could skip matches at the same position after a
zero-length match;
(?<=RE)
(?<!RE)
(?{ CODE })
(?i-x)
(?i:RE)
(?(COND)YES_RE|NO_RE)
(?>RE)
\z
Better debugging output (possibly with colors),
even from non-debugging Perl;
RE engine code now looks like C, not like assembler;
Behaviour of RE modifiable by `use re' directive;
Improved documentation;
Test suite significantly extended;
Syntax [:^upper:] etc., reserved inside character classes;
(?i) localized inside enclosing group;
$( is not interpolated into RE any more;
/RE/g may match at the same position (with non-zero length)
after a zero-length match (bug fix).
Improved malloc()
malloc.c for details.
Quicksort is internally implemented
qsort() routine.
The new qsort() is resistant to inconsistent comparison
functions, so Perl's sort() will not provoke coredumps any more when given poorly written sort
subroutines. (Some C library qsort()s that were being used before used to have this problem.) In our testing,
the new qsort() required the minimal number of pair-wise compares on average, among all
known qsort() implementations.
perlfunc/sort.
Reliable signals
Thread::Signal. Also see INSTALL for how to build a Perl capable of threads.
Reliable stack pointers
More generous treatment of carriage returns
PERL_STRICT_CR when building perl. Of course, all this has nothing whatever to do with how
escapes like \r are handled within strings.
Memory leaks
substr, pos and vec don't leak memory anymore when used in lvalue context. Many small leaks
that impacted applications that embed multiple interpreters have been
fixed.
Better support for multiple interpreters
-DMULTIPLICITY has had many of the details reworked. Some previously global variables that
should have been per-interpreter now are. With care, this allows
interpreters to call each other. See the PerlInterp extension on CPAN.
Behavior of local() on array and hash elements is now well-defined
<CODE>%!</CODE> is transparently tied to the <A HREF="/docs/products/perl/pod.new/./5.00503/i686-linux/Errno.html#">the Errno manpage</A> module
Pseudo-hashes are supported
<CODE>EXPR foreach EXPR</CODE> is supported
Keywords can be globally overridden
<CODE>$^E</CODE> is meaningful on Win32
<CODE>foreach (1..1000000)</CODE> optimized
foreach (1..1000000) is now optimized into a counting loop. It does not try to allocate a
1000000-size list anymore.
<CODE>Foo::</CODE> can be used as implicitly quoted package name
new Foo @args, use the result of the call to Foo() instead of Foo being treated as a literal. The recommended way to write barewords in the
indirect object slot is new Foo:: @args. Note that the method new() is called with a first argument of Foo, not Foo:: when you do that.
<CODE>exists $Foo::{Bar::}</CODE> tests existence of a package
exists $Foo::{Bar::} can be used to test if the Foo::Bar namespace has been created.
Better locale support
Experimental support for 64-bit platforms
prototype() returns useful results on builtins
Extended support for exception handling
die() now accepts a reference value, and $@ gets set to that value in exception traps. This makes it possible to
propagate exception objects. This is an undocumented experimental feature.
Re-blessing in DESTROY() supported for chaining DESTROY() methods
All <CODE>printf</CODE> format conversions are handled internally
New <CODE>INIT</CODE> keyword
INIT subs are like BEGIN and END, but they get run just before the perl runtime begins execution. e.g., the
Perl Compiler makes use of
INIT blocks to initialize and resolve pointers to XSUBs.
New <CODE>lock</CODE> keyword
lock keyword is the fundamental synchronization primitive in threaded perl. When
threads are not enabled, it is currently a noop.
use Thread
has been seen.
New <CODE>qr//</CODE> operator
qr// operator, which is syntactically similar to the other quote-like operators,
is used to create precompiled regular expressions. This compiled form can
now be explicitly passed around in variables, and interpolated in other
regular expressions. See the perlop manpage.
<CODE>our</CODE> is now a reserved word
our will now provoke a warning when using the -w switch.
Tied arrays are now fully supported
Tied handles support is better
4th argument to substr
substr() can now both return and replace in one operation. The
optional 4th argument is the replacement string. See substr.
Negative LENGTH argument to splice
splice() with a negative LENGTH argument now work similar to
what the LENGTH did for substr(). Previously a negative LENGTH
was treated as 0. See splice.
Magic lvalues are now more magical
substr($x, 5) = "hi", the scalar returned by substr() is special, in that any
modifications to it affect $x. (This is called a 'magic lvalue' because an
'lvalue' is something on the left side of an assignment.) Normally, this is
exactly what you would expect to happen, but Perl uses the same magic if
you use substr(), pos(), or vec() in
a context where they might be modified, like taking a reference with \ or as an argument to a sub that modifies @_. In previous versions, this 'magic' only went one way, but now changes to
the scalar the magic refers to ($x in the above example) affect the magic
lvalue too. For instance, this code now acts differently:
$x = "hello";
sub printit {
$x = "g'bye";
print $_[0], "\n";
}
printit(substr($x, 0, 5));
<> now reads in records
$/ is a referenence to an integer, or a scalar that holds an integer,
<> will read in records instead of lines. For more info, see
$/.
pack() format 'Z' supported
Significant bug fixes
<HANDLE> on empty files
$/ set to undef, slurping an empty file returns a string of zero length (instead of undef, as it used to) for the first time the HANDLE is read. Subsequent reads
yield undef.
perl -0777 -pi -e 's/^/foo/' empty_file
perl -pi -e 's/^/foo/' empty_file
Supported Platforms
New Platforms
Changes in existing support
Modules and Pragmata
New Modules
Changes in existing modules
timethese(-5, ...) will run each of the codes for at least 5
CPU seconds. Zero as the ``number of repetitions'' means ``for at least 3
CPU seconds''. The output format has also changed. For example:
cluck(). cluck() warns,
like carp(), but also adds a stack backtrace to the error
message, like confess().
ext/DB_File/Changes.
umask() policy should be honored. There is also
better support for manipulation of .packlist files, and getting information
about installed modules.
Utility Changes
h2ph and related utilities have been vastly overhauled.
perlcc, a new experimental front end for the compiler is available.
configure emulator is now called configure.gnu to avoid trampling on Configure under case-insensitive filesystems.
perldoc used to be rather slow. The slower features are now optional. In
particular, case-insensitive searches need the -i switch, and recursive searches need -r. You can set these switches in the
PERLDOC environment variable to get the old behavior.
Documentation Changes
open().
New Diagnostics
use subs pragma).
CORE:: prefix on the operator (e.g. CORE::log($x)) or by declaring the subroutine to be an object method (see the attrs manpage).
Foo::, but the compiler saw no other uses of that namespace before that point.
Perhaps you need to predeclare a package?
$BADREF = 42;
process $BADREF 1,2,3;
$BADREF->process(1,2,3);
local $ar->{'key'}, where $ar is a reference to a pseudo-hash. That hasn't been
implemented yet, but you can get a similar effect by localizing the
corresponding array element directly -- local $ar->[$ar->[0]{'key'}].
$! errno values.
CORE::word was given to prototype(), but there is no builtin with the
name word.
(?{ ... }) zero-width assertion, which is unsafe. See (?{ code }), and the perlsec manpage.
(?{ ... }) zero-width assertion, but that construct is only allowed when the use re 'eval' pragma is in effect. See (?{ code }).
(?{ ... })
zero-width assertion at run time, as it would when the pattern contains
interpolated values. Since that is a security risk, it is not allowed. If
you insist, you may still do this by explicitly building the pattern from
an interpolated string at run time and using that in an
eval(). See (?{ code }).
bless($ref, $p || 'MyPackage');
%FIELDS hash in the type package at compile time. The
%FIELDS hash is usually set up with the 'fields' pragma.
$arr[time]
instead of $arr[$time].
%hash = { one => 1, two => 2, }; # WRONG
%hash = [ qw/ an anon array / ]; # WRONG
%hash = ( one => 1, two => 2, ); # right
%hash = qw( one 1 two 2 ); # also fine
*foo = undef. This does nothing. It's possible that you really mean undef *foo.
& prefix, or using a package qualifier, e.g. &our(), or Foo::our().
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LC_ALL = "En_US",
LANG = (unset)
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
Obsolete Diagnostics
mktemp() routine failed for some reason while trying
to process a -e switch. Maybe your /tmp partition is full, or clobbered.
Configuration Changes
BUGS
perl -V, will be sent off to <perlbug@perl.com> to be analysed by the Perl porting team.
SEE ALSO
HISTORY