- NAME
- DESCRIPTION
- About the new versioning system
- Incompatible Changes
- Core Changes
- Threads
- Compiler
- Regular Expressions
- Improved malloc()
- Quicksort is internally implemented
- Reliable signals
- Reliable stack pointers
- More generous treatment of carriage returns
- Memory leaks
- Better support for multiple interpreters
- Behavior of local() on array and hash elements is now well-defined
%!
is transparently tied to the Errno module- Pseudo-hashes are supported
EXPR foreach EXPR
is supported- Keywords can be globally overridden
$^E
is meaningful on Win32foreach (1..1000000)
optimizedFoo::
can be used as implicitly quoted package nameexists $Foo::{Bar::}
tests existence of a package- Better locale support
- Experimental support for 64-bit platforms
- prototype() returns useful results on builtins
- Extended support for exception handling
- Re-blessing in DESTROY() supported for chaining DESTROY() methods
- All
printf
format conversions are handled internally - New
INIT
keyword - New
lock
keyword - New
qr//
operator our
is now a reserved word- Tied arrays are now fully supported
- Tied handles support is better
- 4th argument to substr
- Negative LENGTH argument to splice
- Magic lvalues are now more magical
- <> now reads in records
- Supported Platforms
- Modules and Pragmata
- Utility Changes
- Documentation Changes
- New Diagnostics
- Obsolete Diagnostics
- Configuration Changes
- BUGS
- SEE ALSO
- HISTORY
NAME
perl5005delta - what's new for perl5.005
DESCRIPTION
This document describes differences between the 5.004 release and this one.
About the new versioning system
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.
Incompatible Changes
WARNING: This version is not binary compatible with Perl 5.004.
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.
Default installation structure has changed
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.
Perl Source Compatibility
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 INIT<#code%3e-keyword">"code> keyword" in New There have been a large number of changes in the internals to support
the new features in this release. Core sources now require ANSI C compiler An ANSI C compiler is now required to build perl. See INSTALL. All Perl global variables must now be referenced with an explicit prefix 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 See perlapi. Enabling threads has source compatibility issues 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 unambiguously states the terms under which
it may be distributed. Those terms are in general much less restrictive
than the GNU GPL. See perl and the individual perl manpages 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. 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 "qr.html">qr// See banner at the beginning of Perl now contains its own highly optimized qsort() routine. The new qsort()
is resistant to inconsistent comparison functions, so Perl's 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()" in perlsub. See perlref. See perlsyn. See perlsub. See perlvar. 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 See perllocale. 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 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. substr() can now both return and replace in one operation. The optional
4th argument is the replacement string. See substr. 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. When you say something like In previous versions, this would print "hello", but it now prints "g'bye". If 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 (installed
as perldos on some systems). 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
(installed as perlos390 on some systems). 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 (installed
as README_vms on some systems). The hints files for most Unix platforms have seen incremental improvements. Perl compiler and tools. See B. A module to pretty print Perl data. See Data::Dumper. A module to dump perl values to the screen. See Dumpvalue. A module to look up errors more conveniently. See Errno. 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 x seconds instead of guessing the right
number of tests to run. Keeps better time. Carp has a new function cluck(). cluck() warns, like carp(), but also adds
a stack backtrace to the error message, like confess(). 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 accessors methods Re, Im, arg, abs, rho, theta, methods can
($z->Re()) now also act as mutators ($z->Re(3)). A little bit of radial trigonometry (cylindrical and spherical) added,
for example 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 umask() policy should be honored. There is also
better support for manipulation of .packlist files, and getting
information about installed modules. 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 CPAN. Cwd::cwd is faster on most platforms. 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. perlport specifies guidelines on how to write portably. perlmodinstall describes how to fetch and install modules from Some more Perl traps are documented now. See perltrap. perlopentut gives a tutorial on using open(). perlreftut gives a tutorial on references. perlthrtut 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 perlref. (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. bless($ref, $p || 'MyPackage'); (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 %FIELDS hash in the type package at compile time. The %FIELDS hash
is usually set up with the 'fields' pragma. (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" in perllocale. (F) The mktemp() 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 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 perlre. 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 <[email protected]>, with many contributions
from The Perl Porters. Send omissions or corrections to <[email protected]>.INIT<
,
"lock.html">lock keyword" in New "qr.html">qr//
operator" in New -w
switch.
See "our.html">our is now a reserved word" in
operator" in New 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
be referenced with a 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
, B, 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
Other improvements
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
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
%!
is transparently tied to the Errno modulePseudo-hashes are supported
EXPR foreach EXPR
is supportedKeywords can be globally overridden
$^E
is meaningful on Win32foreach (1..1000000)
optimizedforeach (1..1000000)
is now optimized into a counting loop. It does
not try to allocate a 1000000-size list anymore.Foo::
can be used as implicitly quoted package namenew 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.exists $Foo::{Bar::}
tests existence of a packageexists $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 $@
gets set to that
value in exception traps. This makes it possible to propagate
exception objects. This is an undocumented experimental feature.Re-blessing in DESTROY() supported for chaining DESTROY() methods
All
printf
format conversions are handled internallyNew
INIT
keywordINIT
subs are like BEGIN
and END
, but they get run just before
the perl runtime begins execution. e.g., the Perl Compiler makes use of
INIT
blocks to initialize and resolve pointers to XSUBs.New
lock
keywordlock
keyword is the fundamental synchronization primitive
in threaded perl. When threads are not enabled, it is currently a noop.use Thread
has been seen.New
qr//
operatorqr//
operator, which is syntactically similar to the other quote-like
operators, is used to create precompiled regular expressions. This compiled
form can now be explicitly passed around in variables, and interpolated in
other regular expressions. See perlop.our
is now a reserved wordour
will now provoke a warning when
using the -w
switch.Tied arrays are now fully supported
Tied handles support is better
4th argument to substr
Negative LENGTH argument to splice
Magic lvalues are now more magical
substr($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
$/
is a reference to an integer, or a scalar that holds an integer,
<> will read in records instead of lines. For more info, see
"$/" in perlvar.Supported Platforms
New Platforms
Changes in existing support
Modules and Pragmata
New Modules
Changes in existing modules
ext/DB_File/Changes
.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
CPAN
sites.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 attrs).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'}]
.$!
errno values.CORE::word
was given to prototype(), but
there is no builtin with the name word
.(?{ ... })
zero-width assertion, which is unsafe.
See "(?{ code })" in perlre, and perlsec.(?{ ... })
zero-width assertion,
but that construct is only allowed when the use re 'eval'
pragma is
in effect. See "(?{ code })" in perlre.(?{ ... })
zero-width assertion at run time, as it would when the pattern contains
interpolated values. Since that is a security risk, it is not allowed.
If you insist, you may still do this by explicitly building the pattern
from an interpolated string at run time and using that in an eval().
See "(?{ code })" in perlre.$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
Configuration Changes
BUGS
perl -V
, will be sent off to <[email protected]> to be
analysed by the Perl porting team.SEE ALSO
HISTORY