PERLDELTA(1) Perl Programmers Reference Guide PERLDELTA(1)NAMEperldelta - 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 the INSTALL manpage 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 the
INSTALL manpage 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
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generally expected to have very little impact on
compatibility. See the section on New INIT keyword, the
section on New lock keyword, and the section on New qr//
operator.
Certain barewords are now reserved. Use of these will
provoke a warning if you have asked for them with the -w
switch. See the our manpage is now a reserved word.
C Source Compatibility
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 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.)
If you find that your XS extension does not compile
anymore because a perl global is not visible, try
adding a PL_ prefix to the global and rebuild.
It is strongly recommended that all functions in the
Perl API that don't begin with 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.
See the section on API LISTING in the perlguts
manpage.
Enabling threads has source compatibility issues
Perl built with threading enabled requires extensions
to use the new 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.
The API function 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
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threading is enabled.
See the section on C Source Compatibility for more
information.
Binary Compatibility
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.
Security fixes may affect compatibility
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 -e switch do not create temporary files
anymore.
Relaxed new mandatory warnings introduced in 5.004
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 the section on New Diagnostics.
Licensing
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.
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Threads
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 the README.threads manpage.
Mach cthreads (NEXTSTEP, OPENSTEP, Rhapsody) are now
supported by the Thread extension.
Compiler
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.
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.
See ext/B/README, the section on B, and the respective
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compiler modules.
Regular Expressions
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:
Many new and improved optimizations
Changes in the RE engine:
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 $ ;
Changes in Perl code using RE engine:
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;
Many bug fixes
Note that only the major bug fixes are listed here.
See Changes for others.
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;
New regular expression constructs
The following new syntax elements are supported:
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(?<=RE)
(?<!RE)
(?{ CODE })
(?i-x)
(?i:RE)
(?(COND)YES_RE|NO_RE)
(?>RE)
\z
New operator for precompiled regular expressions
See the section on New qr// operator.
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;
Incompatible changes
(?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).
See the perlre manpage and the perlop manpage.
Improved malloc()
See banner at the beginning of malloc.c for details.
Quicksort is internally implemented
Perl now contains its own highly optimized 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.
See perlfunc/sort.
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Reliable signals
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
Thread::Signal. Also see INSTALL for how to build a Perl
capable of threads.
Reliable stack pointers
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.
More generous treatment of carriage returns
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
PERL_STRICT_CR when building perl. Of course, all this
has nothing whatever to do with how escapes like \r are
handled within strings.
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.
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
The build-time option -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
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PerlInterp extension on CPAN.
Behavior of local() on array and hash elements is now
well-defined
See the section on Temporary Values via local() in the
perlsub manpage.
%! is transparently tied to the the Errno manpage module
See the perlvar manpage, and the Errno manpage.
Pseudo-hashes are supported
See the perlref manpage.
EXPR foreach EXPR is supported
See the perlsyn manpage.
Keywords can be globally overridden
See the perlsub manpage.
$^E is meaningful on Win32
See the perlvar manpage.
foreach (1..1000000) optimized
foreach (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 name
Barewords caused unintuitive behavior when a subroutine
with the same name as a package happened to be defined.
Thus, 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.
exists $Foo::{Bar::} tests existence of a package
It was impossible to test for the existence of a package
without actually creating it before. Now exists
$Foo::{Bar::} can be used to test if the Foo::Bar
namespace has been created.
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Better locale support
See the perllocale manpage.
Experimental support for 64-bit platforms
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.
prototype() returns useful results on builtins
See the prototype entry in the perlfunc manpage.
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
See the Destructors entry in the perlobj manpage.
All printf format conversions are handled internally
See the printf entry in the perlfunc manpage.
New INIT 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 lock keyword
The lock keyword is the fundamental synchronization
primitive in threaded perl. When threads are not enabled,
it is currently a noop.
To minimize impact on source compatibility this keyword is
"weak", i.e., any user-defined subroutine of the same name
overrides it, unless a use Thread has been seen.
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New qr// operator
The 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.
our is now a reserved word
Calling a subroutine with the name our will now provoke a
warning when using the -w switch.
Tied arrays are now fully supported
See the Tie::Array manpage.
Tied handles support is better
Several missing hooks have been added. There is also a
new base class for TIEARRAY implementations. See the
Tie::Array manpage.
4th argument to substr
substr() can now both return and replace in one operation.
The optional 4th argument is the replacement string. See
the substr entry in the perlfunc manpage.
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 the splice entry in
the perlfunc manpage.
Magic lvalues are now more magical
When you say something like 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:
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$x = "hello";
sub printit {
$x = "g'bye";
print $_[0], "\n";
}
printit(substr($x, 0, 5));
In previous versions, this would print "hello", but it now
prints "g'bye".
<> now reads in records
If $/ is a referenence to an integer, or a scalar that
holds an integer, <> will read in records instead of
lines. For more info, see the section on $/ in the perlvar
manpage.
pack() format 'Z' supported
The new format type 'Z' is useful for packing and
unpacking null-terminated strings. See the section on
pack in the perlfunc manpage.
Significant bug fixes
<HANDLE> on empty files
With $/ 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.
This means that the following will append "foo" to an
empty file (it used to not do anything before):
perl -0777 -pi -e 's/^/foo/' empty_file
Note that the behavior of:
perl -pi -e 's/^/foo/' empty_file
is unchanged (it continues to leave the file empty).
Supported Platforms
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.
New Platforms
BeOS is now supported. See the README.beos manpage.
DOS is now supported under the DJGPP tools. See the
README.dos manpage.
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GNU/Hurd is now supported.
MiNT is now supported. See the README.mint manpage.
MPE/iX is now supported. See the README.mpeix manpage.
MVS (aka OS390, aka Open Edition) is now supported. See
the README.os390 manpage.
Stratus VOS is now supported. See the README.vos manpage.
Changes in existing support
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 the perlwin32
manpage.
VMS configuration system has been rewritten. See the
README.vms manpage.
The hints files for most Unix platforms have seen
incremental improvements.
Modules and Pragmata
New Modules
B Perl compiler and tools. See the section on B.
Data::Dumper
A module to pretty print Perl data. See the
Data::Dumper manpage.
Dumpvalue
A module to dump perl values to the screen. See the
Dumpvalue manpage.
Errno
A module to look up errors more conveniently. See
the Errno manpage.
File::Spec
A portable API for file operations.
ExtUtils::Installed
Query and manage installed modules.
ExtUtils::Packlist
Manipulate .packlist files.
Fatal
Make functions/builtins succeed or die.
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IPC::SysV
Constants and other support infrastructure for System
V IPC operations in perl.
Test A framework for writing testsuites.
Tie::Array
Base class for tied arrays.
Tie::Handle
Base class for tied handles.
Thread
Perl thread creation, manipulation, and support.
attrs
Set subroutine attributes.
fields
Compile-time class fields.
re Various pragmata to control behavior of regular
expressions.
Changes in existing modules
Benchmark
You can now run tests for n seconds instead of
guessing the right number of tests to run: e.g.
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:
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 Carp has a new function cluck(). cluck() warns, like
carp(), but also adds a stack backtrace to the error
message, like confess().
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CGI CGI has been updated to version 2.42.
Fcntl
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.
Math::Complex
The accessor methods Re, Im, arg, abs, rho, and
theta, can now also act as mutators (accessor
$z->Re(), mutator $z->Re(3)).
Math::Trig
A little bit of radial trigonometry (cylindrical and
spherical) added: radial coordinate conversions and
the great circle distance.
POSIX
POSIX now has its own platform-specific hints files.
DB_File
DB_File supports version 2.x of Berkeley DB. See
ext/DB_File/Changes.
MakeMaker
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.
CPAN See <perlmodinstall> and the CPAN manpage.
Cwd Cwd::cwd is faster on most platforms.
Benchmark
Keeps better time.
Utility Changes
h2ph and related utilities have been vastly overhauled.
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perlcc, a new experimental front end for the compiler is
available.
The crude GNU 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
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 open().
the perlreftut manpage gives a tutorial on references.
the perlthrtut manpage gives a tutorial on threads.
New Diagnostics
Ambiguous call resolved as CORE::%s(), qualify as such or
use &
(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 use subs pragma).
To silently interpret it as the Perl operator, use
the CORE:: prefix on the operator (e.g.
CORE::log($x)) or by declaring the subroutine to be
an object method (see the attrs manpage).
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Bad index while coercing array into hash
(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.
Bareword """"%s"""" refers to nonexistent package
(W) You used a qualified bareword of the form Foo::,
but the compiler saw no other uses of that namespace
before that point. Perhaps you need to predeclare a
package?
Can't call method """"%s"""" on an undefined value
(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:
$BADREF = 42;
process $BADREF 1,2,3;
$BADREF->process(1,2,3);
Can't check filesystem of script """"%s"""" for nosuid
(P) For some reason you can't check the filesystem of
the script for nosuid.
Can't coerce array into hash
(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.
Can't goto subroutine from an eval-string
(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.)
Can't localize pseudo-hash element
(F) You said something like 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'}].
Can't use %%! because Errno.pm is not available
(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 $! errno values.
Cannot find an opnumber for """"%s""""
(F) A string of a form CORE::word was given to
prototype(), but there is no builtin with the name
word.
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Character class syntax [. .] is reserved for future
extensions
(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: "\[." and ".\]".
Character class syntax [: :] is reserved for future
extensions
(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: "\[:" and ":\]".
Character class syntax [= =] is reserved for future
extensions
(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: "\[=" and "=\]".
%s: Eval-group in insecure regular expression
(F) Perl detected tainted data when trying to compile
a regular expression that contains the (?{ ... })
zero-width assertion, which is unsafe. See the
section on (?{ code }) in the perlre manpage, and the
perlsec manpage.
%s: Eval-group not allowed, use re 'eval'
(F) A regular expression contained the (?{ ... })
zero-width assertion, but that construct is only
allowed when the use re 'eval' pragma is in effect.
See the section on (?{ code }) in the perlre manpage.
%s: Eval-group not allowed at run time
(F) Perl tried to compile a regular expression
containing the (?{ ... }) 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 the section on (?{ code }) in the perlre
manpage.
Explicit blessing to '' (assuming package main)
(W) You are blessing a reference to a zero length
string. This has the effect of blessing the
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reference into the package main. This is usually not
what you want. Consider providing a default target
package, e.g. bless($ref, $p || 'MyPackage');
Illegal hex digit ignored
(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.
No such array field
(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.
No such field """"%s"""" in variable %s of type %s
(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.
Out of memory during ridiculously large request
(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., $arr[time] instead of
$arr[$time].
Range iterator outside integer range
(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.
Recursive inheritance detected while looking for method
'%s' in package '%s'
(F) More than 100 levels of inheritance were
encountered while invoking a method. Probably
indicates an unintended loop in your inheritance
hierarchy.
Reference found where even-sized list expected
(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.
%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
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Undefined value assigned to typeglob
(W) An undefined value was assigned to a typeglob, a
la *foo = undef. This does nothing. It's possible
that you really mean undef *foo.
Use of reserved word """"%s"""" is deprecated
(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
& prefix, or using a package qualifier, e.g. &our(),
or Foo::our().
perl: warning: Setting locale failed.
(S) The whole warning message will look something
like:
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").
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 the section on LOCALE
PROBLEMS in the perllocale manpage.
Obsolete Diagnostics
Can't mktemp()
(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.
Can't write to temp file for -e: %s
(F) The write routine failed for some reason while
trying to process a -e switch. Maybe your /tmp
partition is full, or clobbered.
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Removed because -e doesn't use temporary files any
more.
Cannot open temporary file
(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.
regexp too big
(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.
Configuration Changes
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.
BUGS
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 perl -V, will be
sent off to <perlbug@perl.com> to be analysed by the Perl
porting team.
SEE ALSO
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.
HISTORY
Written by Gurusamy Sarathy <gsar@umich.edu>, with many
contributions from The Perl Porters.
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Send omissions or corrections to <perlbug@perl.com>.
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