FM / pod

/usr/share/perl5/pod

Name	Size	Mode	Actions
perl.pod	16667	0644	edit dl rm
perl56delta.pod	107201	0644	edit dl rm
perl58delta.pod	115165	0644	edit dl rm
perl561delta.pod	124713	0644	edit dl rm
perl581delta.pod	38060	0644	edit dl rm
perl582delta.pod	4470	0644	edit dl rm
perl583delta.pod	6335	0644	edit dl rm
perl584delta.pod	7363	0644	edit dl rm
perl585delta.pod	5889	0644	edit dl rm
perl586delta.pod	4651	0644	edit dl rm
perl587delta.pod	8357	0644	edit dl rm
perl588delta.pod	25281	0644	edit dl rm
perl589delta.pod	53904	0644	edit dl rm
perl5004delta.pod	56240	0644	edit dl rm
perl5005delta.pod	34283	0644	edit dl rm
perl5100delta.pod	55533	0644	edit dl rm
perl5101delta.pod	43888	0644	edit dl rm
perl5120delta.pod	89271	0644	edit dl rm
perl5121delta.pod	10141	0644	edit dl rm
perl5122delta.pod	9603	0644	edit dl rm
perl5123delta.pod	4100	0644	edit dl rm
perl5124delta.pod	3672	0644	edit dl rm
perl5125delta.pod	7683	0644	edit dl rm
perl5140delta.pod	144325	0644	edit dl rm
perl5141delta.pod	7966	0644	edit dl rm
perl5142delta.pod	6892	0644	edit dl rm
perl5143delta.pod	7760	0644	edit dl rm
perl5144delta.pod	6327	0644	edit dl rm
perl5160delta.pod	133651	0644	edit dl rm
perl5161delta.pod	6142	0644	edit dl rm
perl5162delta.pod	3594	0644	edit dl rm
perl5163delta.pod	4085	0644	edit dl rm
perl5180delta.pod	119429	0644	edit dl rm
perl5181delta.pod	6597	0644	edit dl rm
perl5182delta.pod	5335	0644	edit dl rm
perl5184delta.pod	4642	0644	edit dl rm
perl5200delta.pod	115698	0644	edit dl rm
perl5201delta.pod	10899	0644	edit dl rm
perl5202delta.pod	12509	0644	edit dl rm
perl5203delta.pod	9392	0644	edit dl rm
perl5220delta.pod	130963	0644	edit dl rm
perl5221delta.pod	10767	0644	edit dl rm
perl5222delta.pod	12629	0644	edit dl rm
perl5223delta.pod	8456	0644	edit dl rm
perl5224delta.pod	4460	0644	edit dl rm
perl5240delta.pod	64923	0644	edit dl rm
perl5241delta.pod	8215	0644	edit dl rm
perl5242delta.pod	4113	0644	edit dl rm
perl5243delta.pod	11428	0644	edit dl rm
perl5244delta.pod	4510	0644	edit dl rm
perl5260delta.pod	101835	0644	edit dl rm
perl5261delta.pod	7927	0644	edit dl rm
perl5262delta.pod	7880	0644	edit dl rm
perl5263delta.pod	7067	0644	edit dl rm
perl5280delta.pod	72113	0644	edit dl rm
perl5281delta.pod	4639	0644	edit dl rm
perl5282delta.pod	6200	0644	edit dl rm
perl5283delta.pod	5111	0644	edit dl rm
perl5300delta.pod	41281	0644	edit dl rm
perl5301delta.pod	5730	0644	edit dl rm
perl5302delta.pod	4682	0644	edit dl rm
perl5303delta.pod	4980	0644	edit dl rm
perl5320delta.pod	54601	0644	edit dl rm
perl5321delta.pod	7003	0644	edit dl rm
perlaix.pod	20438	0644	edit dl rm
perlamiga.pod	5749	0644	edit dl rm
perlandroid.pod	8222	0644	edit dl rm
perlapi.pod	493106	0644	edit dl rm
perlapio.pod	21336	0644	edit dl rm
perlartistic.pod	7010	0644	edit dl rm
perlbook.pod	8386	0644	edit dl rm
perlboot.pod	294	0644	edit dl rm
perlbot.pod	304	0644	edit dl rm
perlbs2000.pod	7994	0644	edit dl rm
perlcall.pod	56738	0644	edit dl rm
perlcheat.pod	4480	0644	edit dl rm
perlclib.pod	9607	0644	edit dl rm
perlcn.pod	4763	0644	edit dl rm
perlcommunity.pod	6983	0644	edit dl rm
perlcygwin.pod	27202	0644	edit dl rm
perldata.pod	49782	0644	edit dl rm
perldbmfilter.pod	4981	0644	edit dl rm
perldebguts.pod	42331	0644	edit dl rm
perldebtut.pod	22152	0644	edit dl rm
perldebug.pod	39383	0644	edit dl rm
perldelta.pod	7003	0644	edit dl rm
perldeprecation.pod	20825	0644	edit dl rm
perldiag.pod	296986	0644	edit dl rm
perldos.pod	10522	0644	edit dl rm
perldsc.pod	25614	0644	edit dl rm
perldtrace.pod	7959	0644	edit dl rm
perlebcdic.pod	84345	0644	edit dl rm
perlembed.pod	37569	0644	edit dl rm
perlexperiment.pod	7234	0644	edit dl rm
perlfork.pod	13355	0644	edit dl rm
perlform.pod	16608	0644	edit dl rm
perlfreebsd.pod	1623	0644	edit dl rm
perlfunc.pod	403777	0644	edit dl rm
perlgit.pod	29591	0644	edit dl rm
perlgov.pod	14481	0644	edit dl rm
perlgpl.pod	13815	0644	edit dl rm
perlguts.pod	162103	0644	edit dl rm
perlhack.pod	43157	0644	edit dl rm
perlhacktips.pod	57692	0644	edit dl rm
perlhacktut.pod	6153	0644	edit dl rm
perlhaiku.pod	1508	0644	edit dl rm
perlhist.pod	56164	0644	edit dl rm
perlhpux.pod	30609	0644	edit dl rm
perlhurd.pod	1994	0644	edit dl rm
perlintern.pod	83565	0644	edit dl rm
perlinterp.pod	33715	0644	edit dl rm
perlintro.pod	22135	0644	edit dl rm
perliol.pod	34804	0644	edit dl rm
perlipc.pod	71529	0644	edit dl rm
perlirix.pod	4415	0644	edit dl rm
perljp.pod	8431	0644	edit dl rm
perlko.pod	12208	0644	edit dl rm
perllexwarn.pod	355	0644	edit dl rm
perllinux.pod	2007	0644	edit dl rm
perllocale.pod	74112	0644	edit dl rm
perllol.pod	9580	0644	edit dl rm
perlmacos.pod	998	0644	edit dl rm
perlmacosx.pod	12124	0644	edit dl rm
perlmod.pod	26197	0644	edit dl rm
perlmodinstall.pod	10261	0644	edit dl rm
perlmodlib.pod	76348	0644	edit dl rm
perlmodstyle.pod	22588	0644	edit dl rm
perlmroapi.pod	3280	0644	edit dl rm
perlnetware.pod	6648	0644	edit dl rm
perlnewmod.pod	11037	0644	edit dl rm
perlnumber.pod	8353	0644	edit dl rm
perlobj.pod	35717	0644	edit dl rm
perlootut.pod	26757	0644	edit dl rm
perlop.pod	148888	0644	edit dl rm
perlopenbsd.pod	1224	0644	edit dl rm
perlopentut.pod	15223	0644	edit dl rm
perlos2.pod	93348	0644	edit dl rm
perlos390.pod	16527	0644	edit dl rm
perlos400.pod	4765	0644	edit dl rm
perlpacktut.pod	51370	0644	edit dl rm
perlperf.pod	49881	0644	edit dl rm
perlplan9.pod	5125	0644	edit dl rm
perlpod.pod	23076	0644	edit dl rm
perlpodspec.pod	68628	0644	edit dl rm
perlpolicy.pod	26562	0644	edit dl rm
perlport.pod	88693	0644	edit dl rm
perlpragma.pod	5176	0644	edit dl rm
perlqnx.pod	6673	0644	edit dl rm
perlre.pod	130817	0644	edit dl rm
perlreapi.pod	30245	0644	edit dl rm
perlrebackslash.pod	32285	0644	edit dl rm
perlrecharclass.pod	49707	0644	edit dl rm
perlref.pod	35432	0644	edit dl rm
perlreftut.pod	18826	0644	edit dl rm
perlreguts.pod	39301	0644	edit dl rm
perlrepository.pod	509	0644	edit dl rm
perlrequick.pod	19141	0644	edit dl rm
perlreref.pod	15590	0644	edit dl rm
perlretut.pod	122527	0644	edit dl rm
perlriscos.pod	1529	0644	edit dl rm
perlrun.pod	55980	0644	edit dl rm
perlsec.pod	27601	0644	edit dl rm
perlsecpolicy.pod	19450	0644	edit dl rm
perlsolaris.pod	29843	0644	edit dl rm
perlsource.pod	7132	0644	edit dl rm
perlstyle.pod	8734	0644	edit dl rm
perlsub.pod	74405	0644	edit dl rm
perlsymbian.pod	15344	0644	edit dl rm
perlsyn.pod	45138	0644	edit dl rm
perlsynology.pod	7960	0644	edit dl rm
perlthrtut.pod	46522	0644	edit dl rm
perltie.pod	39314	0644	edit dl rm
perltoc.pod	701800	0644	edit dl rm
perltodo.pod	372	0644	edit dl rm
perltooc.pod	294	0644	edit dl rm
perltoot.pod	294	0644	edit dl rm
perltrap.pod	10623	0644	edit dl rm
perltru64.pod	8492	0644	edit dl rm
perltw.pod	4463	0644	edit dl rm
perlunicode.pod	91353	0644	edit dl rm
perlunicook.pod	25658	0644	edit dl rm
perlunifaq.pod	13644	0644	edit dl rm
perluniintro.pod	38647	0644	edit dl rm
perluniprops.pod	441614	0644	edit dl rm
perlunitut.pod	7951	0644	edit dl rm
perlutil.pod	7291	0644	edit dl rm
perlvar.pod	82577	0644	edit dl rm
perlvms.pod	50823	0644	edit dl rm
perlvos.pod	3843	0644	edit dl rm
perlwin32.pod	40317	0644	edit dl rm

Edit: /usr/share/perl5/pod/perldeprecation.pod (20825B)

=head1 NAME

perldeprecation - list Perl deprecations

=head1 DESCRIPTION

The purpose of this document is to document what has been deprecated
in Perl, and by which version the deprecated feature will disappear,
or, for already removed features, when it was removed.

This document will try to discuss what alternatives for the deprecated
features are available.

The deprecated features will be grouped by the version of Perl in
which they will be removed.

=head2 Perl 5.34

There are no deprecations or fatalizations scheduled for Perl 5.34.

=head2 Perl 5.32

=head3 Constants from lexical variables potentially modified elsewhere

You wrote something like

my $var;
    $sub = sub () { $var };

but $var is referenced elsewhere and could be modified after the C<sub>
expression is evaluated.  Either it is explicitly modified elsewhere
(C<$var = 3>) or it is passed to a subroutine or to an operator like
C<printf> or C<map>, which may or may not modify the variable.

Traditionally, Perl has captured the value of the variable at that
point and turned the subroutine into a constant eligible for inlining.
In those cases where the variable can be modified elsewhere, this
breaks the behavior of closures, in which the subroutine captures
the variable itself, rather than its value, so future changes to the
variable are reflected in the subroutine's return value.

If you intended for the subroutine to be eligible for inlining, then
make sure the variable is not referenced elsewhere, possibly by
copying it:

my $var2 = $var;
    $sub = sub () { $var2 };

If you do want this subroutine to be a closure that reflects future
changes to the variable that it closes over, add an explicit C<return>:

my $var;
    $sub = sub () { return $var };

This usage was deprecated and as of Perl 5.32 is no longer allowed.

=head3 Use of strings with code points over 0xFF as arguments to C<vec>

C<vec> views its string argument as a sequence of bits.  A string
containing a code point over 0xFF is nonsensical.  This usage is
deprecated in Perl 5.28, and was removed in Perl 5.32.

=head3 Use of code points over 0xFF in string bitwise operators

The string bitwise operators, C<&>, C<|>, C<^>, and C<~>, treat their
operands as strings of bytes. As such, values above 0xFF are
nonsensical. Some instances of these have been deprecated since Perl
5.24, and were made fatal in 5.28, but it turns out that in cases where
the wide characters did not affect the end result, no deprecation
notice was raised, and so remain legal.  Now, all occurrences either are
fatal or raise a deprecation warning, so that the remaining legal
occurrences became fatal in 5.32.

An example of this is

"" & "\x{100}"

The wide character is not used in the C<&> operation because the left
operand is shorter.  This now throws an exception.

=head3 hostname() doesn't accept any arguments

The function C<hostname()> in the L<Sys::Hostname> module has always
been documented to be called with no arguments.  Historically it has not
enforced this, and has actually accepted and ignored any arguments.  As a
result, some users have got the mistaken impression that an argument does
something useful.  To avoid these bugs, the function is being made strict.
Passing arguments was deprecated in Perl 5.28 and became fatal in Perl 5.32.

=head3 Unescaped left braces in regular expressions

The simple rule to remember, if you want to match a literal C<{>
character (U+007B C<LEFT CURLY BRACKET>) in a regular expression
pattern, is to escape each literal instance of it in some way.
Generally easiest is to precede it with a backslash, like C<\{>
or enclose it in square brackets (C<[{]>).  If the pattern
delimiters are also braces, any matching right brace (C<}>) should
also be escaped to avoid confusing the parser, for example,

qr{abc\{def\}ghi}

Forcing literal C<{> characters to be escaped will enable the Perl
language to be extended in various ways in future releases.  To avoid
needlessly breaking existing code, the restriction is not enforced in
contexts where there are unlikely to ever be extensions that could
conflict with the use there of C<{> as a literal.  A non-deprecation
warning that the left brace is being taken literally is raised in
contexts where there could be confusion about it.

Literal uses of C<{> were deprecated in Perl 5.20, and some uses of it
started to give deprecation warnings since. These cases were made fatal
in Perl 5.26. Due to an oversight, not all cases of a use of a literal
C<{> got a deprecation warning.  Some cases started warning in Perl 5.26,
and were made fatal in Perl 5.30.  Other cases started in Perl 5.28,
and were made fatal in 5.32.

=head3 In XS code, use of various macros dealing with UTF-8.

The macros below now require an extra parameter than in versions prior
to Perl 5.32.  The final parameter in each one is a pointer into the
string supplied by the first parameter beyond which the input will not
be read.  This prevents potential reading beyond the end of the buffer.
C<isALPHANUMERIC_utf8>,
C<isASCII_utf8>,
C<isBLANK_utf8>,
C<isCNTRL_utf8>,
C<isDIGIT_utf8>,
C<isIDFIRST_utf8>,
C<isPSXSPC_utf8>,
C<isSPACE_utf8>,
C<isVERTWS_utf8>,
C<isWORDCHAR_utf8>,
C<isXDIGIT_utf8>,
C<isALPHANUMERIC_LC_utf8>,
C<isALPHA_LC_utf8>,
C<isASCII_LC_utf8>,
C<isBLANK_LC_utf8>,
C<isCNTRL_LC_utf8>,
C<isDIGIT_LC_utf8>,
C<isGRAPH_LC_utf8>,
C<isIDCONT_LC_utf8>,
C<isIDFIRST_LC_utf8>,
C<isLOWER_LC_utf8>,
C<isPRINT_LC_utf8>,
C<isPSXSPC_LC_utf8>,
C<isPUNCT_LC_utf8>,
C<isSPACE_LC_utf8>,
C<isUPPER_LC_utf8>,
C<isWORDCHAR_LC_utf8>,
C<isXDIGIT_LC_utf8>,
C<toFOLD_utf8>,
C<toLOWER_utf8>,
C<toTITLE_utf8>,
and
C<toUPPER_utf8>.

Since Perl 5.26, this functionality with the extra parameter has been
available by using a corresponding macro to each one of these, and whose
name is formed by appending C<_safe> to the base name.  There is no
change to the functionality of those.  For example, C<isDIGIT_utf8_safe>
corresponds to C<isDIGIT_utf8>, and both now behave identically.  All
are documented in L<perlapi/Character case changing> and
L<perlapi/Character classification>.

This change was originally scheduled for 5.30, but was delayed until
5.32.

=head3 C<< File::Glob::glob() >> was removed

C<< File::Glob >> has a function called C<< glob >>, which just calls
C<< bsd_glob >>.

C<< File::Glob::glob() >> was deprecated in Perl 5.8. A deprecation
message was issued from Perl 5.26 onwards, and the function has now
disappeared in Perl 5.30.

Code using C<< File::Glob::glob() >> should call
C<< File::Glob::bsd_glob() >> instead.

=head2 Perl 5.30

=head3 C<< $* >> is no longer supported

Before Perl 5.10, setting C<< $* >> to a true value globally enabled
multi-line matching within a string. This relique from the past lost
its special meaning in 5.10. Use of this variable will be a fatal error
in Perl 5.30, freeing the variable up for a future special meaning.

To enable multiline matching one should use the C<< /m >> regexp
modifier (possibly in combination with C<< /s >>). This can be set
on a per match bases, or can be enabled per lexical scope (including
a whole file) with C<< use re '/m' >>.

=head3 C<< $# >> is no longer supported

This variable used to have a special meaning -- it could be used
to control how numbers were formatted when printed. This seldom
used functionality was removed in Perl 5.10. In order to free up
the variable for a future special meaning, its use will be a fatal
error in Perl 5.30.

To specify how numbers are formatted when printed, one is advised
to use C<< printf >> or C<< sprintf >> instead.

=head3 Assigning non-zero to C<< $[ >> is fatal

This variable (and the corresponding C<array_base> feature and
L<arybase> module) allowed changing the base for array and string
indexing operations.

Setting this to a non-zero value has been deprecated since Perl 5.12 and
throws a fatal error as of Perl 5.30.

=head3 C<< File::Glob::glob() >> will disappear

C<< File::Glob >> has a function called C<< glob >>, which just calls
C<< bsd_glob >>. However, its prototype is different from the prototype
of C<< CORE::glob >>, and hence, C<< File::Glob::glob >> should not
be used.

C<< File::Glob::glob() >> was deprecated in Perl 5.8. A deprecation
message was issued from Perl 5.26 onwards, and the function will
disappear in Perl 5.30.

Code using C<< File::Glob::glob() >> should call
C<< File::Glob::bsd_glob() >> instead.

=head3 Unescaped left braces in regular expressions (for 5.30)

See L</Unescaped left braces in regular expressions> above.

=head3 Unqualified C<dump()>

Use of C<dump()> instead of C<CORE::dump()> was deprecated in Perl 5.8,
and an unqualified C<dump()> will no longer be available in Perl 5.30.

See L<perlfunc/dump>.

=head3 Using my() in false conditional.

There has been a long-standing bug in Perl that causes a lexical variable
not to be cleared at scope exit when its declaration includes a false
conditional.  Some people have exploited this bug to achieve a kind of
static variable.  To allow us to fix this bug, people should not be
relying on this behavior.

Instead, it's recommended one uses C<state> variables to achieve the
same effect:

use 5.10.0;
    sub count {state $counter; return ++ $counter}
    say count ();    # Prints 1
    say count ();    # Prints 2

C<state> variables were introduced in Perl 5.10.

Alternatively, you can achieve a similar static effect by
declaring the variable in a separate block outside the function, e.g.,

sub f { my $x if 0; return $x++ }

becomes

{ my $x; sub f { return $x++ } }

The use of C<my()> in a false conditional has been deprecated in
Perl 5.10, and became a fatal error in Perl 5.30.

=head3 Reading/writing bytes from/to :utf8 handles.

The sysread(), recv(), syswrite() and send() operators are
deprecated on handles that have the C<:utf8> layer, either explicitly, or
implicitly, eg., with the C<:encoding(UTF-16LE)> layer.

Both sysread() and recv() currently use only the C<:utf8> flag for the stream,
ignoring the actual layers.  Since sysread() and recv() do no UTF-8
validation they can end up creating invalidly encoded scalars.

Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise ignoring
any layers.  If the flag is set, both write the value UTF-8 encoded, even if
the layer is some different encoding, such as the example above.

Ideally, all of these operators would completely ignore the C<:utf8> state,
working only with bytes, but this would result in silently breaking existing
code.  To avoid this a future version of perl will throw an exception when
any of sysread(), recv(), syswrite() or send() are called on handle with the
C<:utf8> layer.

In Perl 5.30, it will no longer be possible to use sysread(), recv(),
syswrite() or send() to read or send bytes from/to :utf8 handles.

=head3 Use of unassigned code point or non-standalone grapheme for a delimiter.

A grapheme is what appears to a native-speaker of a language to be a
character.  In Unicode (and hence Perl) a grapheme may actually be
several adjacent characters that together form a complete grapheme.  For
example, there can be a base character, like "R" and an accent, like a
circumflex "^", that appear to be a single character when displayed,
with the circumflex hovering over the "R".

As of Perl 5.30, use of delimiters which are non-standalone graphemes is
fatal, in order to move the language to be able to accept
multi-character graphemes as delimiters.

Also, as of Perl 5.30, delimiters which are unassigned code points
but that may someday become assigned are prohibited.  Otherwise, code
that works today would fail to compile if the currently unassigned
delimiter ends up being something that isn't a stand-alone grapheme.
Because Unicode is never going to assign L<non-character code
points|perlunicode/Noncharacter code points>, nor L<code points that are
above the legal Unicode maximum|perlunicode/Beyond Unicode code
points>, those can be delimiters.

=head2 Perl 5.28

=head3 Attributes C<< :locked >> and C<< :unique >>

The attributes C<< :locked >> (on code references) and C<< :unique >>
(on array, hash and scalar references) have had no effect since 
Perl 5.005 and Perl 5.8.8 respectively. Their use has been deprecated
since.

As of Perl 5.28, these attributes are syntax errors. Since the
attributes do not do anything, removing them from your code fixes
the syntax error; and removing them will not influence the behaviour
of your code.

=head3 Bare here-document terminators

Perl has allowed you to use a bare here-document terminator to have the
here-document end at the first empty line. This practise was deprecated
in Perl 5.000; as of Perl 5.28, using a bare here-document terminator
throws a fatal error.

You are encouraged to use the explicitly quoted form if you wish to
use an empty line as the terminator of the here-document:

print <<"";
    Print this line.

# Previous blank line ends the here-document.

=head3 Setting $/ to a reference to a non-positive integer

You assigned a reference to a scalar to C<$/> where the
referenced item is not a positive integer.  In older perls this B<appeared>
to work the same as setting it to C<undef> but was in fact internally
different, less efficient and with very bad luck could have resulted in
your file being split by a stringified form of the reference.

In Perl 5.20.0 this was changed so that it would be B<exactly> the same as
setting C<$/> to undef, with the exception that this warning would be
thrown.

As of Perl 5.28, setting C<$/> to a reference of a non-positive
integer throws a fatal error.

You are recommended to change your code to set C<$/> to C<undef> explicitly
if you wish to slurp the file.

=head3 Limit on the value of Unicode code points.

Unicode only allows code points up to 0x10FFFF, but Perl allows
much larger ones. Up till Perl 5.28, it was allowed to use code
points exceeding the maximum value of an integer (C<IV_MAX>).
However, that did break the perl interpreter in some constructs,
including causing it to hang in a few cases.  The known problem
areas were in C<tr///>, regular expression pattern matching using
quantifiers, as quote delimiters in C<qI<X>...I<X>> (where I<X> is
the C<chr()> of a large code point), and as the upper limits in
loops.

The use of out of range code points was deprecated in Perl 5.24; as of
Perl 5.28 using a code point exceeding C<IV_MAX> throws a fatal error.

If your code is to run on various platforms, keep in mind that the upper
limit depends on the platform. It is much larger on 64-bit word sizes
than 32-bit ones. For 32-bit integers, C<IV_MAX> equals C<0x7FFFFFFF>,
for 64-bit integers, C<IV_MAX> equals C<0x7FFFFFFFFFFFFFFF>.

=head3 Use of comma-less variable list in formats.

It was allowed to use a list of variables in a format, without
separating them with commas. This usage has been deprecated
for a long time, and as of Perl 5.28, this throws a fatal error.

=head3 Use of C<\N{}>

Use of C<\N{}> with nothing between the braces was deprecated in
Perl 5.24, and throws a fatal error as of Perl 5.28.

Since such a construct is equivalent to using an empty string,
you are recommended to remove such C<\N{}> constructs.

=head3 Using the same symbol to open a filehandle and a dirhandle

It used to be legal to use C<open()> to associate both a
filehandle and a dirhandle to the same symbol (glob or scalar).
This idiom is likely to be confusing, and it was deprecated in
Perl 5.10.

Using the same symbol to C<open()> a filehandle and a dirhandle
throws a fatal error as of Perl 5.28.

You should be using two different symbols instead.

=head3 ${^ENCODING} is no longer supported.

The special variable C<${^ENCODING}> was used to implement
the C<encoding> pragma. Setting this variable to anything other
than C<undef> was deprecated in Perl 5.22. Full deprecation
of the variable happened in Perl 5.25.3.

Setting this variable to anything other than an undefined value
throws a fatal error as of Perl 5.28.

=head3 C<< B::OP::terse >>

This method, which just calls C<< B::Concise::b_terse >>, has been
deprecated, and disappeared in Perl 5.28. Please use 
C<< B::Concise >> instead.

=head3 Use of inherited AUTOLOAD for non-method %s::%s() is no longer allowed

As an (ahem) accidental feature, C<AUTOLOAD> subroutines were looked
up as methods (using the C<@ISA> hierarchy) even when the subroutines
to be autoloaded were called as plain functions (e.g. C<Foo::bar()>),
not as methods (e.g. C<< Foo->bar() >> or C<< $obj->bar() >>).

This bug was deprecated in Perl 5.004, has been rectified in Perl 5.28
by using method lookup only for methods' C<AUTOLOAD>s.

The simple rule is:  Inheritance will not work when autoloading
non-methods.  The simple fix for old code is:  In any module that used
to depend on inheriting C<AUTOLOAD> for non-methods from a base class
named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
startup.

In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.

=head3 Use of code points over 0xFF in string bitwise operators

The string bitwise operators, C<&>, C<|>, C<^>, and C<~>, treat
their operands as strings of bytes. As such, values above 0xFF 
are nonsensical. Using such code points with these operators
was deprecated in Perl 5.24, and is fatal as of Perl 5.28.

=head3 In XS code, use of C<to_utf8_case()>

This function has been removed as of Perl 5.28; instead convert to call
the appropriate one of:
L<C<toFOLD_utf8_safe>|perlapi/toFOLD_utf8_safe>.
L<C<toLOWER_utf8_safe>|perlapi/toLOWER_utf8_safe>,
L<C<toTITLE_utf8_safe>|perlapi/toTITLE_utf8_safe>,
or
L<C<toUPPER_utf8_safe>|perlapi/toUPPER_utf8_safe>.

=head2 Perl 5.26

=head3 C<< --libpods >> in C<< Pod::Html >>

Since Perl 5.18, the option C<< --libpods >> has been deprecated, and
using this option did not do anything other than producing a warning.

The C<< --libpods >> option is no longer recognized as of Perl 5.26.

=head3 The utilities C<< c2ph >> and C<< pstruct >>

These old, perl3-era utilities have been deprecated in favour of
C<< h2xs >> for a long time. As of Perl 5.26, they have been removed.

=head3 Trapping C<< $SIG {__DIE__} >> other than during program exit.

The C<$SIG{__DIE__}> hook is called even inside an C<eval()>. It was
never intended to happen this way, but an implementation glitch made
this possible. This used to be deprecated, as it allowed strange action
at a distance like rewriting a pending exception in C<$@>. Plans to
rectify this have been scrapped, as users found that rewriting a
pending exception is actually a useful feature, and not a bug.

Perl never issued a deprecation warning for this; the deprecation
was by documentation policy only. But this deprecation has been 
lifted as of Perl 5.26.

=head3 Malformed UTF-8 string in "%s"

This message indicates a bug either in the Perl core or in XS
code. Such code was trying to find out if a character, allegedly
stored internally encoded as UTF-8, was of a given type, such as
being punctuation or a digit.  But the character was not encoded
in legal UTF-8.  The C<%s> is replaced by a string that can be used
by knowledgeable people to determine what the type being checked
against was.

Passing malformed strings was deprecated in Perl 5.18, and
became fatal in Perl 5.26.

=head2 Perl 5.24

=head3 Use of C<< *glob{FILEHANDLE} >>

The use of C<< *glob{FILEHANDLE} >> was deprecated in Perl 5.8.
The intention was to use C<< *glob{IO} >> instead, for which 
C<< *glob{FILEHANDLE} >> is an alias.

However, this feature was undeprecated in Perl 5.24.

=head3 Calling POSIX::%s() is deprecated

The following functions in the C<POSIX> module are no longer available:
C<isalnum>, C<isalpha>, C<iscntrl>, C<isdigit>, C<isgraph>, C<islower>,  
C<isprint>, C<ispunct>, C<isspace>, C<isupper>, and C<isxdigit>.  The 
functions are buggy and don't work on UTF-8 encoded strings.  See their
entries in L<POSIX> for more information.

The functions were deprecated in Perl 5.20, and removed in Perl 5.24.

=head2 Perl 5.16

=head3 Use of %s on a handle without * is deprecated

It used to be possible to use C<tie>, C<tied> or C<untie> on a scalar
while the scalar holds a typeglob. This caused its filehandle to be
tied. It left no way to tie the scalar itself when it held a typeglob,
and no way to untie a scalar that had had a typeglob assigned to it.

This was deprecated in Perl 5.14, and the bug was fixed in Perl 5.16.

So now C<tie $scalar> will always tie the scalar, not the handle it holds.
To tie the handle, use C<tie *$scalar> (with an explicit asterisk).  The same
applies to C<tied *$scalar> and C<untie *$scalar>.

=head1 SEE ALSO

L<warnings>, L<diagnostics>.

=cut

=head1 NAME perldeprecation - list Perl deprecations =head1 DESCRIPTION The purpose of this document is to document what has been deprecated in Perl, and by which version the deprecated feature will disappear, or, for already removed features, when it was removed. This document will try to discuss what alternatives for the deprecated features are available. The deprecated features will be grouped by the version of Perl in which they will be removed. =head2 Perl 5.34 There are no deprecations or fatalizations scheduled for Perl 5.34. =head2 Perl 5.32 =head3 Constants from lexical variables potentially modified elsewhere You wrote something like my $var; $sub = sub () { $var }; but $var is referenced elsewhere and could be modified after the C_{expression is evaluated. Either it is explicitly modified elsewhere
(C<$var = 3>) or it is passed to a subroutine or to an operator like
C or C, which may or may not modify the variable.

Traditionally, Perl has captured the value of the variable at that
point and turned the subroutine into a constant eligible for inlining.
In those cases where the variable can be modified elsewhere, this
breaks the behavior of closures, in which the subroutine captures
the variable itself, rather than its value, so future changes to the
variable are reflected in the subroutine's return value.

If you intended for the subroutine to be eligible for inlining, then
make sure the variable is not referenced elsewhere, possibly by
copying it:

my $var2 = $var;
$sub = sub () { $var2 };

If you do want this subroutine to be a closure that reflects future
changes to the variable that it closes over, add an explicit C:

my $var;
$sub = sub () { return $var };

This usage was deprecated and as of Perl 5.32 is no longer allowed.

=head3 Use of strings with code points over 0xFF as arguments to C

C views its string argument as a sequence of bits. A string
containing a code point over 0xFF is nonsensical. This usage is
deprecated in Perl 5.28, and was removed in Perl 5.32.

=head3 Use of code points over 0xFF in string bitwise operators

The string bitwise operators, C<&>, C<|>, C<^>, and C<~>, treat their
operands as strings of bytes. As such, values above 0xFF are
nonsensical. Some instances of these have been deprecated since Perl
5.24, and were made fatal in 5.28, but it turns out that in cases where
the wide characters did not affect the end result, no deprecation
notice was raised, and so remain legal. Now, all occurrences either are
fatal or raise a deprecation warning, so that the remaining legal
occurrences became fatal in 5.32.

An example of this is

"" & "\x{100}"

The wide character is not used in the C<&> operation because the left
operand is shorter. This now throws an exception.

=head3 hostname() doesn't accept any arguments

The function C in the L module has always
been documented to be called with no arguments. Historically it has not
enforced this, and has actually accepted and ignored any arguments. As a
result, some users have got the mistaken impression that an argument does
something useful. To avoid these bugs, the function is being made strict.
Passing arguments was deprecated in Perl 5.28 and became fatal in Perl 5.32.

=head3 Unescaped left braces in regular expressions

The simple rule to remember, if you want to match a literal C<{>
character (U+007B C) in a regular expression
pattern, is to escape each literal instance of it in some way.
Generally easiest is to precede it with a backslash, like C<\{>
or enclose it in square brackets (C<[{]>). If the pattern
delimiters are also braces, any matching right brace (C<}>) should
also be escaped to avoid confusing the parser, for example,

qr{abc\{def\}ghi}

Forcing literal C<{> characters to be escaped will enable the Perl
language to be extended in various ways in future releases. To avoid
needlessly breaking existing code, the restriction is not enforced in
contexts where there are unlikely to ever be extensions that could
conflict with the use there of C<{> as a literal. A non-deprecation
warning that the left brace is being taken literally is raised in
contexts where there could be confusion about it.

Literal uses of C<{> were deprecated in Perl 5.20, and some uses of it
started to give deprecation warnings since. These cases were made fatal
in Perl 5.26. Due to an oversight, not all cases of a use of a literal
C<{> got a deprecation warning. Some cases started warning in Perl 5.26,
and were made fatal in Perl 5.30. Other cases started in Perl 5.28,
and were made fatal in 5.32.

=head3 In XS code, use of various macros dealing with UTF-8.

The macros below now require an extra parameter than in versions prior
to Perl 5.32. The final parameter in each one is a pointer into the
string supplied by the first parameter beyond which the input will not
be read. This prevents potential reading beyond the end of the buffer.
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
C,
and
C.

Since Perl 5.26, this functionality with the extra parameter has been
available by using a corresponding macro to each one of these, and whose
name is formed by appending C<_safe> to the base name. There is no
change to the functionality of those. For example, C
corresponds to C, and both now behave identically. All
are documented in L and
L.

This change was originally scheduled for 5.30, but was delayed until
5.32.

=head3 C<< File::Glob::glob() >> was removed

C<< File::Glob >> has a function called C<< glob >>, which just calls
C<< bsd_glob >>.

C<< File::Glob::glob() >> was deprecated in Perl 5.8. A deprecation
message was issued from Perl 5.26 onwards, and the function has now
disappeared in Perl 5.30.

Code using C<< File::Glob::glob() >> should call
C<< File::Glob::bsd_glob() >> instead.

=head2 Perl 5.30

=head3 C<< $* >> is no longer supported

Before Perl 5.10, setting C<< $* >> to a true value globally enabled
multi-line matching within a string. This relique from the past lost
its special meaning in 5.10. Use of this variable will be a fatal error
in Perl 5.30, freeing the variable up for a future special meaning.

To enable multiline matching one should use the C<< /m >> regexp
modifier (possibly in combination with C<< /s >>). This can be set
on a per match bases, or can be enabled per lexical scope (including
a whole file) with C<< use re '/m' >>.

=head3 C<< $# >> is no longer supported

This variable used to have a special meaning -- it could be used
to control how numbers were formatted when printed. This seldom
used functionality was removed in Perl 5.10. In order to free up
the variable for a future special meaning, its use will be a fatal
error in Perl 5.30.

To specify how numbers are formatted when printed, one is advised
to use C<< printf >> or C<< sprintf >> instead.

=head3 Assigning non-zero to C<< $[ >> is fatal

This variable (and the corresponding C feature and
L module) allowed changing the base for array and string
indexing operations.

Setting this to a non-zero value has been deprecated since Perl 5.12 and
throws a fatal error as of Perl 5.30.

=head3 C<< File::Glob::glob() >> will disappear

C<< File::Glob >> has a function called C<< glob >>, which just calls
C<< bsd_glob >>. However, its prototype is different from the prototype
of C<< CORE::glob >>, and hence, C<< File::Glob::glob >> should not
be used.

C<< File::Glob::glob() >> was deprecated in Perl 5.8. A deprecation
message was issued from Perl 5.26 onwards, and the function will
disappear in Perl 5.30.

Code using C<< File::Glob::glob() >> should call
C<< File::Glob::bsd_glob() >> instead.

=head3 Unescaped left braces in regular expressions (for 5.30)

See L above.

=head3 Unqualified C

Use of C instead of C was deprecated in Perl 5.8,
and an unqualified C will no longer be available in Perl 5.30.

See L.

=head3 Using my() in false conditional.

There has been a long-standing bug in Perl that causes a lexical variable
not to be cleared at scope exit when its declaration includes a false
conditional. Some people have exploited this bug to achieve a kind of
static variable. To allow us to fix this bug, people should not be
relying on this behavior.

Instead, it's recommended one uses C variables to achieve the
same effect:

use 5.10.0;
sub count {state $counter; return ++ $counter}
say count (); # Prints 1
say count (); # Prints 2

C variables were introduced in Perl 5.10.

Alternatively, you can achieve a similar static effect by
declaring the variable in a separate block outside the function, e.g.,

sub f { my $x if 0; return $x++ }

becomes

{ my $x; sub f { return $x++ } }

The use of C in a false conditional has been deprecated in
Perl 5.10, and became a fatal error in Perl 5.30.

=head3 Reading/writing bytes from/to :utf8 handles.

The sysread(), recv(), syswrite() and send() operators are
deprecated on handles that have the C<:utf8> layer, either explicitly, or
implicitly, eg., with the C<:encoding(UTF-16LE)> layer.

Both sysread() and recv() currently use only the C<:utf8> flag for the stream,
ignoring the actual layers. Since sysread() and recv() do no UTF-8
validation they can end up creating invalidly encoded scalars.

Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise ignoring
any layers. If the flag is set, both write the value UTF-8 encoded, even if
the layer is some different encoding, such as the example above.

Ideally, all of these operators would completely ignore the C<:utf8> state,
working only with bytes, but this would result in silently breaking existing
code. To avoid this a future version of perl will throw an exception when
any of sysread(), recv(), syswrite() or send() are called on handle with the
C<:utf8> layer.

In Perl 5.30, it will no longer be possible to use sysread(), recv(),
syswrite() or send() to read or send bytes from/to :utf8 handles.

=head3 Use of unassigned code point or non-standalone grapheme for a delimiter.

A grapheme is what appears to a native-speaker of a language to be a
character. In Unicode (and hence Perl) a grapheme may actually be
several adjacent characters that together form a complete grapheme. For
example, there can be a base character, like "R" and an accent, like a
circumflex "^", that appear to be a single character when displayed,
with the circumflex hovering over the "R".

As of Perl 5.30, use of delimiters which are non-standalone graphemes is
fatal, in order to move the language to be able to accept
multi-character graphemes as delimiters.

Also, as of Perl 5.30, delimiters which are unassigned code points
but that may someday become assigned are prohibited. Otherwise, code
that works today would fail to compile if the currently unassigned
delimiter ends up being something that isn't a stand-alone grapheme.
Because Unicode is never going to assign L, nor L, those can be delimiters.

=head2 Perl 5.28

=head3 Attributes C<< :locked >> and C<< :unique >>

The attributes C<< :locked >> (on code references) and C<< :unique >>
(on array, hash and scalar references) have had no effect since
Perl 5.005 and Perl 5.8.8 respectively. Their use has been deprecated
since.

As of Perl 5.28, these attributes are syntax errors. Since the
attributes do not do anything, removing them from your code fixes
the syntax error; and removing them will not influence the behaviour
of your code.

=head3 Bare here-document terminators

Perl has allowed you to use a bare here-document terminator to have the
here-document end at the first empty line. This practise was deprecated
in Perl 5.000; as of Perl 5.28, using a bare here-document terminator
throws a fatal error.

You are encouraged to use the explicitly quoted form if you wish to
use an empty line as the terminator of the here-document:

print <<"";
Print this line.

# Previous blank line ends the here-document.

=head3 Setting $/ to a reference to a non-positive integer

You assigned a reference to a scalar to C<$/> where the
referenced item is not a positive integer. In older perls this B
to work the same as setting it to C but was in fact internally
different, less efficient and with very bad luck could have resulted in
your file being split by a stringified form of the reference.

In Perl 5.20.0 this was changed so that it would be B the same as
setting C<$/> to undef, with the exception that this warning would be
thrown.

As of Perl 5.28, setting C<$/> to a reference of a non-positive
integer throws a fatal error.

You are recommended to change your code to set C<$/> to C explicitly
if you wish to slurp the file.

=head3 Limit on the value of Unicode code points.

Unicode only allows code points up to 0x10FFFF, but Perl allows
much larger ones. Up till Perl 5.28, it was allowed to use code
points exceeding the maximum value of an integer (C).
However, that did break the perl interpreter in some constructs,
including causing it to hang in a few cases. The known problem
areas were in C, regular expression pattern matching using
quantifiers, as quote delimiters in C...I> (where I is
the C of a large code point), and as the upper limits in
loops.

The use of out of range code points was deprecated in Perl 5.24; as of
Perl 5.28 using a code point exceeding C throws a fatal error.

If your code is to run on various platforms, keep in mind that the upper
limit depends on the platform. It is much larger on 64-bit word sizes
than 32-bit ones. For 32-bit integers, C equals C<0x7FFFFFFF>,
for 64-bit integers, C equals C<0x7FFFFFFFFFFFFFFF>.

=head3 Use of comma-less variable list in formats.

It was allowed to use a list of variables in a format, without
separating them with commas. This usage has been deprecated
for a long time, and as of Perl 5.28, this throws a fatal error.

=head3 Use of C<\N{}>

Use of C<\N{}> with nothing between the braces was deprecated in
Perl 5.24, and throws a fatal error as of Perl 5.28.

Since such a construct is equivalent to using an empty string,
you are recommended to remove such C<\N{}> constructs.

=head3 Using the same symbol to open a filehandle and a dirhandle

It used to be legal to use C to associate both a
filehandle and a dirhandle to the same symbol (glob or scalar).
This idiom is likely to be confusing, and it was deprecated in
Perl 5.10.

Using the same symbol to C a filehandle and a dirhandle
throws a fatal error as of Perl 5.28.

You should be using two different symbols instead.

=head3 ${^ENCODING} is no longer supported.

The special variable C<${^ENCODING}> was used to implement
the C pragma. Setting this variable to anything other
than C was deprecated in Perl 5.22. Full deprecation
of the variable happened in Perl 5.25.3.

Setting this variable to anything other than an undefined value
throws a fatal error as of Perl 5.28.

=head3 C<< B::OP::terse >>

This method, which just calls C<< B::Concise::b_terse >>, has been
deprecated, and disappeared in Perl 5.28. Please use
C<< B::Concise >> instead.

=head3 Use of inherited AUTOLOAD for non-method %s::%s() is no longer allowed

As an (ahem) accidental feature, C subroutines were looked
up as methods (using the C<@ISA> hierarchy) even when the subroutines
to be autoloaded were called as plain functions (e.g. C),
not as methods (e.g. C<< Foo->bar() >> or C<< $obj->bar() >>).

This bug was deprecated in Perl 5.004, has been rectified in Perl 5.28
by using method lookup only for methods' Cs.

The simple rule is: Inheritance will not work when autoloading
non-methods. The simple fix for old code is: In any module that used
to depend on inheriting C for non-methods from a base class
named C, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
startup.

In code that currently says C
you should remove AutoLoader from @ISA and change C to
C.

=head3 Use of code points over 0xFF in string bitwise operators

The string bitwise operators, C<&>, C<|>, C<^>, and C<~>, treat
their operands as strings of bytes. As such, values above 0xFF
are nonsensical. Using such code points with these operators
was deprecated in Perl 5.24, and is fatal as of Perl 5.28.

=head3 In XS code, use of C

This function has been removed as of Perl 5.28; instead convert to call
the appropriate one of:
L|perlapi/toFOLD_utf8_safe>.
L|perlapi/toLOWER_utf8_safe>,
L|perlapi/toTITLE_utf8_safe>,
or
L|perlapi/toUPPER_utf8_safe>.

=head2 Perl 5.26

=head3 C<< --libpods >> in C<< Pod::Html >>

Since Perl 5.18, the option C<< --libpods >> has been deprecated, and
using this option did not do anything other than producing a warning.

The C<< --libpods >> option is no longer recognized as of Perl 5.26.

=head3 The utilities C<< c2ph >> and C<< pstruct >>

These old, perl3-era utilities have been deprecated in favour of
C<< h2xs >> for a long time. As of Perl 5.26, they have been removed.

=head3 Trapping C<< $SIG {__DIE__} >> other than during program exit.

The C<$SIG{__DIE__}> hook is called even inside an C. It was
never intended to happen this way, but an implementation glitch made
this possible. This used to be deprecated, as it allowed strange action
at a distance like rewriting a pending exception in C<$@>. Plans to
rectify this have been scrapped, as users found that rewriting a
pending exception is actually a useful feature, and not a bug.

Perl never issued a deprecation warning for this; the deprecation
was by documentation policy only. But this deprecation has been
lifted as of Perl 5.26.

=head3 Malformed UTF-8 string in "%s"

This message indicates a bug either in the Perl core or in XS
code. Such code was trying to find out if a character, allegedly
stored internally encoded as UTF-8, was of a given type, such as
being punctuation or a digit. But the character was not encoded
in legal UTF-8. The C<%s> is replaced by a string that can be used
by knowledgeable people to determine what the type being checked
against was.

Passing malformed strings was deprecated in Perl 5.18, and
became fatal in Perl 5.26.

=head2 Perl 5.24

=head3 Use of C<< *glob{FILEHANDLE} >>

The use of C<< *glob{FILEHANDLE} >> was deprecated in Perl 5.8.
The intention was to use C<< *glob{IO} >> instead, for which
C<< *glob{FILEHANDLE} >> is an alias.

However, this feature was undeprecated in Perl 5.24.

=head3 Calling POSIX::%s() is deprecated

The following functions in the C module are no longer available:
C, C, C, C, C, C,
C, C, C, C, and C. The
functions are buggy and don't work on UTF-8 encoded strings. See their
entries in L for more information.

The functions were deprecated in Perl 5.20, and removed in Perl 5.24.

=head2 Perl 5.16

=head3 Use of %s on a handle without * is deprecated

It used to be possible to use C, C or C on a scalar
while the scalar holds a typeglob. This caused its filehandle to be
tied. It left no way to tie the scalar itself when it held a typeglob,
and no way to untie a scalar that had had a typeglob assigned to it.

This was deprecated in Perl 5.14, and the bug was fixed in Perl 5.16.

So now C will always tie the scalar, not the handle it holds.
To tie the handle, use C (with an explicit asterisk). The same
applies to C and C.

=head1 SEE ALSO

L, L.

=cut}