PERL5005DELTA(1) Perl Programmers Reference Guide PERL5005DELTA(1)
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 "New "INIT" keyword",
"New "lock" keyword", and "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 ""our" 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 perlapi.
• 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("@",GV_ADD)" 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.
See "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 "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 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.
Core Changes
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 README.threads.
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", B, and the respective 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:
(?<=RE)
(?<!RE)
(?{ CODE })
(?i-x)
(?i:RE)
(?(COND)YES_RE|NO_RE)
(?>RE)
\z
New operator for precompiled regular expressions
See "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 perlre and perlop.
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".
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 "PerlInterp" extension on CPAN.
Behavior of local() on array and hash elements is now well-defined
See "Temporary Values via local()" in perlsub.
"%!" is transparently tied to the Errno module
See perlvar, and Errno.
Pseudo-hashes are supported
See perlref.
"EXPR foreach EXPR" is supported
See perlsyn.
Keywords can be globally overridden
See perlsub.
$^E is meaningful on Win32
See perlvar.
"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.
Better locale support
See perllocale.
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 "prototype" in perlfunc.
Extended support for exception handling
die() now accepts a reference value, and $@ gets set to that value in
exception traps. This makes it possible to propagate exception objects.
This is an undocumented experimental feature.
Re-blessing in DESTROY() supported for chaining DESTROY() methods
See "Destructors" in perlobj.
All "printf" format conversions are handled internally
See "printf" in perlfunc.
New "INIT" keyword
"INIT" subs are like "BEGIN" and "END", but they get run just before the
perl runtime begins execution. e.g., the Perl Compiler makes use of
"INIT" blocks to initialize and resolve pointers to XSUBs.
New "lock" keyword
The "lock" keyword is the fundamental synchronization primitive in
threaded perl. When threads are not enabled, it is currently a noop.
To minimize impact on source compatibility this keyword is "weak", i.e.,
any user-defined subroutine of the same name overrides it, unless a "use
Thread" has been seen.
New "qr//" operator
The "qr//" operator, which is syntactically similar to the other quote-
like operators, is used to create precompiled regular expressions. This
compiled form can now be explicitly passed around in variables, and
interpolated in other regular expressions. See perlop.
"our" is now a reserved word
Calling a subroutine with the name "our" will now provoke a warning when
using the "-w" switch.
Tied arrays are now fully supported
See Tie::Array.
Tied handles support is better
Several missing hooks have been added. There is also a new base class
for TIEARRAY implementations. See Tie::Array.
4th argument to substr
substr() can now both return and replace in one operation. The optional
4th argument is the replacement string. See "substr" in perlfunc.
Negative LENGTH argument to splice
splice() with a negative LENGTH argument now work similar to what the
LENGTH did for substr(). Previously a negative LENGTH was treated as 0.
See "splice" in perlfunc.
Magic lvalues are now more magical
When you say something like "substr($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:
$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 $/ is a reference to an integer, or a scalar that holds an integer,
<> will read in records instead of lines. For more info, see "$/" in
perlvar.
Supported Platforms
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 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.
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 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.
Modules and Pragmata
New Modules
B Perl compiler and tools. See B.
Data::Dumper
A module to pretty print Perl data. See Data::Dumper.
Dumpvalue
A module to dump perl values to the screen. See Dumpvalue.
Errno
A module to look up errors more conveniently. See Errno.
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.
IPC::SysV
Constants and other support infrastructure for System V IPC
operations in perl.
Test
A framework for writing test suites.
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 x seconds instead of guessing the right
number of tests to run.
Keeps better time.
Carp
Carp has a new function cluck(). cluck() warns, like carp(), but
also adds a stack backtrace to the error message, like confess().
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 accessors methods Re, Im, arg, abs, rho, theta, methods can
($z->Re()) now also act as mutators ($z->Re(3)).
Math::Trig
A little bit of radial trigonometry (cylindrical and spherical)
added, for example 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 CPAN.
Cwd Cwd::cwd is faster on most platforms.
Utility Changes
"h2ph" and related utilities have been vastly overhauled.
"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.
perlport specifies guidelines on how to write portably.
perlmodinstall describes how to fetch and install modules from "CPAN"
sites.
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.
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 "attrs").
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 perlref.
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".
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 "(?{ code })" in perlre, and perlsec.
%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 "(?{ code })" in perlre.
%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 "(?{ code })" in perlre.
Explicit blessing to '' (assuming package main)
(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');
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' %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
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 "LOCALE
PROBLEMS" in perllocale.
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.
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 perlre.
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@activestate.com>, with many
contributions from The Perl Porters.
Send omissions or corrections to <perlbug@perl.com>.
perl v5.40.1 2026-08-30 PERL5005DELTA(1)
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