you thought. Normally it's pretty easy to disambiguate it by supplying
a missing quote, operator, parenthesis pair or declaration.
+=item Ambiguous use of -%s resolved as -&%s()
+
+(S ambiguous) You wrote something like C<-foo>, which might be the
+string C<"-foo">, or a call to the function C<foo>, negated. If you meant
+the string, just write C<"-foo">. If you meant the function call,
+write C<-foo()>.
+
=item Ambiguous use of %c resolved as operator %c
(S ambiguous) C<%>, C<&>, and C<*> are both infix operators (modulus,
that does not coincide with a built-in keyword, or by simply turning
off warnings with C<no warnings 'ambiguous';>.
-=item Ambiguous use of -%s resolved as -&%s()
-
-(S ambiguous) You wrote something like C<-foo>, which might be the
-string C<"-foo">, or a call to the function C<foo>, negated. If you meant
-the string, just write C<"-foo">. If you meant the function call,
-write C<-foo()>.
-
=item '|' and '<' may not both be specified on command line
(F) An error peculiar to VMS. Perl does its own command line
(X) The malloc package that comes with Perl had an internal failure.
-=item Assertion failed: file "%s"
+=item Assertion %s failed: file "%s", line %d
(X) A general assertion failed. The file in question must be examined.
obsolete, has had no effect since 5005 threads were removed, and
will be removed in a future release of Perl 5.
+=item Attribute prototype(%s) discards earlier prototype attribute in same sub
+
+(W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
+example. Since each sub can only have one prototype, the earlier
+declaration(s) are discarded while the last one is applied.
+
=item Attribute "unique" is deprecated
(D deprecated) You have used the attributes pragma to modify
The :unique attribute has had no effect since Perl 5.8.8, and
will be removed in a future release of Perl 5.
-=item Attribute prototype(%s) discards earlier prototype attribute in same sub
-
-(W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
-example. Since each sub can only have one prototype, the earlier
-declaration(s) are discarded while the last one is applied.
-
=item av_reify called on tied array
(S debugging) This indicates that something went wrong and Perl got I<very>
be guaranteed (due to the errors), and since subsequent code likely
depends on its correct operation, Perl just gave up.
-=item \1 better written as $1
+=item \%d better written as $%d
(W syntax) Outside of patterns, backreferences live on as variables.
The use of backslashes is grandfathered on the right-hand side of a
(W unopened) You tried binmode() on a filehandle that was never opened.
Check your control flow and number of arguments.
-=item "\b{" is deprecated; use "\b\{" or "\b[{]" instead in regex; marked by <-- HERE in m/%s/
+=item "\b{" is deprecated; use "\b\{" or "\b[{]" instead in regex; marked
+by S<<-- HERE> in m/%s/
-=item "\B{" is deprecated; use "\B\{" or "\B[{]" instead in regex; marked by <-- HERE in m/%s/
+=item "\B{" is deprecated; use "\B\{" or "\B[{]" instead in regex; marked
+by S<<-- HERE> in m/%s/
(D deprecated) Use of an unescaped "{" immediately following
a C<\b> or C<\B> is now deprecated so as to reserve its use for Perl
(F) You had a (sub-)template that ends with a '/'. There must be
another template code following the slash. See L<perlfunc/pack>.
-=item Code point 0x%X is not Unicode, all \p{} matches fail; all \P{} matches
-succeed
-
=item Code point 0x%X is not Unicode, may not be portable
-(S utf8, non_unicode) You had a code point above the Unicode maximum
+(S non_unicode) You had a code point above the Unicode maximum
of U+10FFFF.
Perl allows strings to contain a superset of Unicode code points, up
but not higher. Code points above 0xFFFF_FFFF require larger than a
32 bit word.
-None of the Unicode or Perl-defined properties will match a non-Unicode
-code point. For example,
-
- chr(0x7FF_FFFF) =~ /\p{Any}/
-
-will not match, because the code point is not in Unicode. But
-
- chr(0x7FF_FFFF) =~ /\P{Any}/
-
-will match.
-
-This may be counterintuitive at times, as both these fail:
-
- chr(0x110000) =~ /\p{ASCII_Hex_Digit=True}/ # Fails.
- chr(0x110000) =~ /\p{ASCII_Hex_Digit=False}/ # Also fails!
-
-and both these succeed:
-
- chr(0x110000) =~ /\P{ASCII_Hex_Digit=True}/ # Succeeds.
- chr(0x110000) =~ /\P{ASCII_Hex_Digit=False}/ # Also succeeds!
-
=item %s: Command not found
(A) You've accidentally run your script through B<csh> or another shell
you have also specified an explicit size for the string. See
L<perlfunc/pack>.
+=for comment
+The following are used in lib/diagnostics.t for testing two =items that
+share the same description. Changes here need to be propagated to there
+
=item Deep recursion on anonymous subroutine
=item Deep recursion on subroutine "%s"
it's loaded, etc.
-=item (?(DEFINE)....) does not allow branches in regex; marked by <-- HERE in
-m/%s/
+=item (?(DEFINE)....) does not allow branches in regex; marked by
+S<<-- HERE> in m/%s/
(F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
most likely cause of this error is that you left out a parenthesis inside
(F) You cannot put a repeat count of any kind right after the '/' code.
See L<perlfunc/pack>.
+=item Don't know how to get file name
+
+(P) C<PerlIO_getname>, a perl internal I/O function specific to VMS, was
+somehow called on another platform. This should not happen.
+
=item Don't know how to handle magic of type \%o
(P) The internal handling of magical variables has been cursed.
(W unpack) You have applied the same modifier more than once after a
type in a pack template. See L<perlfunc/pack>.
+=item each on reference is experimental
+
+(S experimental::autoderef) C<each> with a scalar argument is experimental and
+may change or be removed in a future Perl version. If you want to take
+the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
=item elseif should be elsif
(S syntax) There is no keyword "elseif" in Perl because Larry thinks
named "elseif" for the class returned by the following block. This is
unlikely to be what you want.
-=item Empty \%c{} in regex; marked by <-- HERE in m/%s/
+=item Empty \%c{} in regex; marked by S<<-- HERE> in m/%s/
(F) C<\p> and C<\P> are used to introduce a named Unicode property, as
described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
assertion, but that construct is only allowed when the C<use re 'eval'>
pragma is in effect. See L<perlre/(?{ code })>.
-=item EVAL without pos change exceeded limit in regex; marked by <-- HERE in
-m/%s/
+=item EVAL without pos change exceeded limit in regex; marked by
+S<<-- HERE> in m/%s/
(F) You used a pattern that nested too many EVAL calls without consuming
any text. Restructure the pattern so that text is consumed.
(W exiting) You are exiting a substitution by unconventional means, such
as a return, a goto, or a loop control statement.
-=item Expecting close bracket in regex; marked by <-- HERE in m/%s/
+=item Expecting close bracket in regex; marked by S<<-- HERE> in m/%s/
(F) You wrote something like
L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>,
but omitted the C<")">.
-=item Expecting '(?flags:(?[...' in regex; marked by <-- HERE in m/%s/
+=item Expecting '(?flags:(?[...' in regex; marked by S<<-- HERE> in m/%s/
(F) The C<(?[...])> extended character class regular expression construct
only allows character classes (including character class escapes like
CHECK, INIT, or END subroutine. Processing of the remainder of the
queue of such routines has been prematurely ended.
-=item False [] range "%s" in regex; marked by <-- HERE in m/%s/
+=item False [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
(W regexp)(F) A character class range must start and end at a literal
character, not another character class like C<\d> or C<[:alpha:]>. The "-"
in your false range is interpreted as a literal "-". In a C<(?[...])>
construct, this is an error, rather than a warning. Consider quoting
-the "-", "\-". The <-- HERE shows whereabouts in the regular expression
+the "-", "\-". The S<<-- HERE> shows whereabouts in the regular expression
the problem was discovered. See L<perlre>.
=item Fatal VMS error (status=%d) at %s, line %d
has since been undefined.
=item Group name must start with a non-digit word character in regex; marked by
-<-- HERE in m/%s/
+S<<-- HERE> in m/%s/
(F) Group names must follow the rules for perl identifiers, meaning
they must start with a non-digit word character. A common cause of
names (like C<$A::B>). You've exceeded Perl's limits. Future versions
of Perl are likely to eliminate these arbitrary limitations.
-=item Ignoring zero length \N{} in character class in regex; marked by <-- HERE in m/%s/
+=item Ignoring zero length \N{} in character class in regex; marked by
+S<<-- HERE> in m/%s/
(W regexp) Named Unicode character escapes C<(\N{...})> may return a
zero-length sequence. When such an escape is used in a character class
(W digit) You may have tried to use an 8 or 9 in an octal number.
Interpretation of the octal number stopped before the 8 or 9.
-=item Illegal pattern in regex; marked by <-- HERE in m/%s/
+=item Illegal pattern in regex; marked by S<<-- HERE> in m/%s/
(F) You wrote something like
Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
also result in this warning. See L<perlcall/G_KEEPERR>.
-=item Incomplete expression within '(?[ ])' in regex; marked by <-- HERE in m/%s/
+=item Incomplete expression within '(?[ ])' in regex; marked by S<<-- HERE>
+in m/%s/
(F) There was a syntax error within the C<(?[ ])>. This can happen if the
expression inside the construct was completely empty, or if there are
function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
-=item In '(?...)', splitting the initial '(?' is deprecated in regex; marked by <-- HERE in m/%s/
+=item In '(?...)', splitting the initial '(?' is deprecated in regex;
+marked by S<<-- HERE> in m/%s/
(D regexp, deprecated) The two-character sequence C<"(?"> in
this context in a regular expression pattern should be an
element larger than typically 2**32. This is usually caused by trying
to use some odd mathematical operation as a version, like 100/9.
-=item Internal disaster in regex; marked by <-- HERE in m/%s/
+=item Internal disaster in regex; marked by S<<-- HERE> in m/%s/
(P) Something went badly wrong in the regular expression parser.
-The <-- HERE shows whereabouts in the regular expression the problem was
+The S<<-- HERE> shows whereabouts in the regular expression the problem was
discovered.
=item Internal inconsistency in tracking vforks
message, then an XS module tried to call that routine with one such
reserved format.
-=item Internal urp in regex; marked by <-- HERE in m/%s/
+=item Internal urp in regex; marked by S<<-- HERE> in m/%s/
(P) Something went badly awry in the regular expression parser. The
-<-- HERE shows whereabouts in the regular expression the problem was
+S<<-- HERE> shows whereabouts in the regular expression the problem was
discovered.
=item %s (...) interpreted as function
(F) The indicated attributes for a subroutine or variable were not
recognized by Perl or by a user-supplied handler. See L<attributes>.
-=item Invalid character in charnames alias definition; marked by <-- HERE in '%s
+=item Invalid character in charnames alias definition; marked by
+S<<-- HERE> in '%s
(F) You tried to create a custom alias for a character name, with
the C<:alias> option to C<use charnames> and the specified character in
arguments produce a warning as of 5.20. The parts after the \0 were
formerly ignored by system calls.
-=item Invalid character in \N{...}; marked by <-- HERE in \N{%s}
+=item Invalid character in \N{...}; marked by S<<-- HERE> in \N{%s}
(F) Only certain characters are valid for character names. The
indicated one isn't. See L<charnames/CUSTOM ALIASES>.
(W printf) Perl does not understand the given format conversion. See
L<perlfunc/sprintf>.
-=item Invalid escape in the specified encoding in regex; marked by <-- HERE in
-m/%s/
+=item Invalid escape in the specified encoding in regex; marked by
+S<<-- HERE> in m/%s/
-(W regexp) The numeric escape (for example C<\xHH>) of value < 256
+(W regexp)(F) The numeric escape (for example C<\xHH>) of value < 256
didn't correspond to a single character through the conversion
from the encoding specified by the encoding pragma.
-The escape was replaced with REPLACEMENT CHARACTER (U+FFFD) instead.
-The <-- HERE shows whereabouts in the regular expression the
+The escape was replaced with REPLACEMENT CHARACTER (U+FFFD)
+instead, except within S<C<(?[ ])>>, where it is a fatal error.
+The S<<-- HERE> shows whereabouts in the regular expression the
escape was discovered.
=item Invalid hexadecimal number in \N{U+...}
-=item Invalid hexadecimal number in \N{U+...} in regex; marked by <-- HERE in
-m/%s/
+=item Invalid hexadecimal number in \N{U+...} in regex; marked by
+S<<-- HERE> in m/%s/
(F) The character constant represented by C<...> is not a valid hexadecimal
number. Either it is empty, or you tried to use a character other than
with the B<-D> option with no flags to see the list of acceptable values.
See also L<perlrun/-Dletters>.
-=item Invalid [] range "%s" in regex; marked by <-- HERE in m/%s/
+=item Invalid [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
(F) The range specified in a character class had a minimum character
greater than the maximum character. One possibility is that you forgot the
C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
-up to C<ff>. The <-- HERE shows whereabouts in the regular expression the
+up to C<ff>. The S<<-- HERE> shows whereabouts in the regular expression the
problem was discovered. See L<perlre>.
=item Invalid range "%s" in transliteration operator
Perhaps the internals were modified directly in some way or
an arbitrary reference was blessed into the "version" class.
-=item In '(*VERB...)', splitting the initial '(*' is deprecated in regex; marked by <-- HERE in m/%s/
+=item In '(*VERB...)', splitting the initial '(*' is deprecated in regex;
+marked by S<<-- HERE> in m/%s/
(D regexp, deprecated) The two-character sequence C<"(*"> in
this context in a regular expression pattern should be an
(P) The regular expression parser is confused.
+=item keys on reference is experimental
+
+(S experimental::autoderef) C<keys> with a scalar argument is experimental and
+may change or be removed in a future Perl version. If you want to take
+the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
=item Label not found for "last %s"
(F) You named a loop to break out of, but you're not currently in a loop
(F) Perl thought it was reading UTF-16 encoded character data but while
doing it Perl met a malformed Unicode surrogate.
-=item %s matches null string many times in regex; marked by <-- HERE in m/%s/
+=item Matched non-Unicode code point 0x%X against Unicode property; may
+not be portable
+
+(S non_unicode) Perl allows strings to contain a superset of
+Unicode code points; each code point may be as large as what is storable
+in an unsigned integer on your system, but these may not be accepted by
+other languages/systems. This message occurs when you matched a string
+containing such a code point against a regular expression pattern, and
+the code point was matched against a Unicode property, C<\p{...}> or
+C<\P{...}>. Unicode properties are only defined on Unicode code points,
+so the result of this match is undefined by Unicode, but Perl (starting
+in v5.20) treats non-Unicode code points as if they were typical
+unassigned Unicode ones, and matched this one accordingly. Whether a
+given property matches these code points or not is specified in
+L<perluniprops/Properties accessible through \p{} and \P{}>.
+
+This message is suppressed (unless it has been made fatal) if it is
+immaterial to the results of the match if the code point is Unicode or
+not. For example, the property C<\p{ASCII_Hex_Digit}> only can match
+the 22 characters C<[0-9A-Fa-f]>, so obviously all other code points,
+Unicode or not, won't match it. (And C<\P{ASCII_Hex_Digit}> will match
+every code point except these 22.)
+
+Getting this message indicates that the outcome of the match arguably
+should have been the opposite of what actually happened. If you think
+that is the case, you may wish to make the C<non_unicode> warnings
+category fatal; if you agree with Perl's decision, you may wish to turn
+off this category.
+
+See L<perlunicode/Beyond Unicode code points> for more information.
+
+=item %s matches null string many times in regex; marked by S<<-- HERE> in
+m/%s/
(W regexp) The pattern you've specified would be an infinite loop if the
-regular expression engine didn't specifically check for that. The <-- HERE
+regular expression engine didn't specifically check for that. The S<<-- HERE>
shows whereabouts in the regular expression the problem was discovered.
See L<perlre>.
=item Missing braces on \N{}
-=item Missing braces on \N{} in regex; marked by <-- HERE in m/%s/
+=item Missing braces on \N{} in regex; marked by S<<-- HERE> in m/%s/
(F) Wrong syntax of character name literal C<\N{charname}> within
double-quotish context. This can also happen when there is a space
(F) A double-quoted string ended with "\c", without the required control
character name.
+=item Missing ']' in prototype for %s : %s
+
+(W illegalproto) A grouping was started with C<[> but never closed with C<]>.
+
=item Missing name in "%s sub"
-(F) The reserved syntax for lexically scoped subroutines requires that
+(F) The syntax for lexically scoped subroutines requires that
they have a name with which they can be found.
=item Missing $ on loop variable
are always mentioned with the $ in Perl, unlike in the shells, where it
can vary from one line to the next.
-=item Missing ']' in prototype for %s : %s
-
-(W illegalproto) A grouping was started with C<[> but never closed with
-C<]>.
-
=item (Missing operator before %s?)
(S syntax) This is an educated guess made in conjunction with the message
"%s found where operator expected". Often the missing operator is a comma.
-=item Missing right brace on \%c{} in regex; marked by <-- HERE in m/%s/
+=item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
(F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
list of arguments, but have forgotten to specify a piped open mode.
See L<perlfunc/open> for details.
+=item mprotect for COW string %p %u failed with %d
+
+(S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
+L<perlguts/"Copy on Write">), but a shared string buffer
+could not be made read-only.
+
=item mprotect for %p %u failed with %d
+(S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see L<perlhacktips>),
+but an op tree could not be made read-only.
+
+=item mprotect RW for COW string %p %u failed with %d
+
+(S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
+L<perlguts/"Copy on Write">), but a read-only shared string
+buffer could not be made mutable.
+
=item mprotect RW for %p %u failed with %d
(S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see
-L<perlhacktips>), but an op tree could not be made read-only, or a
-read-only op tree could not be made mutable before freeing the ops.
+L<perlhacktips>), but a read-only op tree could not be made
+mutable before freeing the ops.
=item msg%s not implemented
=item Name "%s::%s" used only once: possible typo
-(W once) Typographical errors often show up as unique variable names.
-If you had a good reason for having a unique name, then just mention it
-again somehow to suppress the message. The C<our> declaration is provided
-for this purpose.
+(W once) Typographical errors often show up as unique variable
+names. If you had a good reason for having a unique name, then
+just mention it again somehow to suppress the message. The C<our>
+declaration is provided for this purpose.
-NOTE: This warning detects symbols that have been used only once so $c, @c,
-%c, *c, &c, sub c{}, c(), and c (the filehandle or format) are considered
-the same; if a program uses $c only once but also uses any of the others it
-will not trigger this warning. Symbols beginning with an underscore and
-symbols using special identifiers (q.v. L<perldata>) are exempt from this
-warning.
+NOTE: This warning detects symbols that have been used only once
+so $c, @c, %c, *c, &c, sub c{}, c(), and c (the filehandle or
+format) are considered the same; if a program uses $c only once
+but also uses any of the others it will not trigger this warning.
+Symbols beginning with an underscore and symbols using special
+identifiers (q.v. L<perldata>) are exempt from this warning.
-=item Need exactly 3 octal digits in regex; marked by <-- HERE in m/%s/
+=item Need exactly 3 octal digits in regex; marked by S<<-- HERE> in m/%s/
(F) Within S<C<(?[ ])>>, all constants interpreted as octal need to be
exactly 3 digits long. This helps catch some ambiguities. If your
(F) When C<vec> is called in an lvalue context, the second argument must be
greater than or equal to zero.
-=item Nested quantifiers in regex; marked by <-- HERE in m/%s/
+=item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
(F) You can't quantify a quantifier without intervening parentheses.
-So things like ** or +* or ?* are illegal. The <-- HERE shows
+So things like ** or +* or ?* are illegal. The S<<-- HERE> shows
whereabouts in the regular expression the problem was discovered.
Note that the minimal matching quantifiers, C<*?>, C<+?>, and
See L<mro>.
=item \N in a character class must be a named character: \N{...} in regex;
-marked by <-- HERE in m/%s/
+marked by S<<-- HERE> in m/%s/
+
+(F) The new (as of Perl 5.12) meaning of C<\N> as C<[^\n]> is not valid in a
+bracketed character class, for the same reason that C<.> in a character
+class loses its specialness: it matches almost everything, which is
+probably not what you want.
-(F) The new (5.12) meaning of C<\N> as C<[^\n]> is not valid in
-a bracketed character class, for the same reason that C<.> in
-a character class loses its specialness: it matches almost
-everything, which is probably not what you want.
+=item \N{} in character class restricted to one character in regex; marked
+by S<<-- HERE> in m/%s/
+
+(F) Named Unicode character escapes C<(\N{...})> may return a
+multi-character sequence. Such an escape may not be used in
+a character class, because character classes always match one
+character of input. Check that the correct escape has been used,
+and the correct charname handler is in scope. The S<<-- HERE> shows
+whereabouts in the regular expression the problem was discovered.
-=item \N{NAME} must be resolved by the lexer in regex; marked by <-- HERE in m/%s/
+=item \N{NAME} must be resolved by the lexer in regex; marked by
+S<<-- HERE> in m/%s/
(F) When compiling a regex pattern, an unresolved named character or
sequence was encountered. This can happen in any of several ways that
it throwing an exception, use C<maybe::next::method>
or C<next::can>. See L<mro>.
-=item Non-hex character in regex; marked by <-- HERE in m/%s/
+=item Non-hex character in regex; marked by S<<-- HERE> in m/%s/
(F) In a regular expression, there was a non-hexadecimal character where
a hex one was expected, like
(?[ [ \xDG ] ])
(?[ [ \x{DEKA} ] ])
-=item Non-octal character in regex; marked by <-- HERE in m/%s/
+=item Non-octal character in regex; marked by S<<-- HERE> in m/%s/
(F) In a regular expression, there was a non-octal character where
an octal one was expected, like
of Perl. Check the #! line, or manually feed your script into Perl
yourself.
-=item (?[...]) not valid in locale in regex; marked by <-- HERE in m/%s/
+=item (?[...]) not valid in locale in regex; marked by S<<-- HERE> in m/%s/
(F) C<(?[...])> cannot be used within the scope of a C<S<use locale>> or with
an C</l> regular expression modifier, as that would require deferring
Although legal, this idiom might render your code confusing
and is deprecated.
-=item Operand with no preceding operator in regex; marked by <-- HERE in m/%s/
+=item Operand with no preceding operator in regex; marked by S<<-- HERE> in
+m/%s/
(F) You wrote something like
=item Operation "%s" returns its argument for non-Unicode code point 0x%X
-(S utf8, non_unicode) You performed an operation requiring Unicode
-semantics on a code point that is not in Unicode, so what it should do
-is not defined. Perl has chosen to have it do nothing, and warn you.
+(S non_unicode) You performed an operation requiring Unicode semantics
+on a code point that is not in Unicode, so what it should do is not
+defined. Perl has chosen to have it do nothing, and warn you.
If the operation shown is "ToFold", it means that case-insensitive
matching in a regular expression was done on the code point.
=item Operation "%s" returns its argument for UTF-16 surrogate U+%X
-(S utf8, surrogate) You performed an operation requiring Unicode
-semantics on a Unicode surrogate. Unicode frowns upon the use of
-surrogates for anything but storing strings in UTF-16, but semantics
-are (reluctantly) defined for the surrogates, and they are to do
-nothing for this operation. Because the use of surrogates can be
-dangerous, Perl warns.
+(S surrogate) You performed an operation requiring Unicode
+semantics on a Unicode surrogate. Unicode frowns upon the use
+of surrogates for anything but storing strings in UTF-16, but
+semantics are (reluctantly) defined for the surrogates, and
+they are to do nothing for this operation. Because the use of
+surrogates can be dangerous, Perl warns.
If the operation shown is "ToFold", it means that case-insensitive
matching in a regular expression was done on the code point.
=item panic: kid popen errno read
-(F) forked child returned an incomprehensible message about its errno.
+(F) A forked child returned an incomprehensible message about its errno.
=item panic: last, type=%u
=item panic: memory wrap
-(P) Something tried to allocate more memory than possible.
+(P) Something tried to allocate either more memory than possible or a
+negative amount.
=item panic: pad_alloc, %p!=%p
(P) scan_num() got called on something that wasn't a number.
-=item panic: Sequence (?{...}): no code block found
+=item panic: Sequence (?{...}): no code block found in regex m/%s/
-(P) while compiling a pattern that has embedded (?{}) or (??{}) code
+(P) While compiling a pattern that has embedded (?{}) or (??{}) code
blocks, perl couldn't locate the code block that should have already been
seen and compiled by perl before control passed to the regex compiler.
that a method requires a package that has not been loaded.
=item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
-utility to report; in regex; marked by <-- HERE in m/%s/
+utility to report; in regex; marked by S<<-- HERE> in m/%s/
(S regexp) You used a regular expression with case-insensitive matching,
and there is a bug in Perl in which the built-in regular expression
(F) The unpack format P must have an explicit size, not "*".
-=item POSIX class [:%s:] unknown in regex; marked by <-- HERE in m/%s/
+=item pop on reference is experimental
+
+(S experimental::autoderef) C<pop> with a scalar argument is experimental and
+may change or be removed in a future Perl version. If you want to take
+the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
-(F) The class in the character class [: :] syntax is unknown. The <-- HERE
+=item POSIX class [:%s:] unknown in regex; marked by S<< <-- HERE in m/%s/ >>
+
+(F) The class in the character class [: :] syntax is unknown. The S<<-- HERE>
shows whereabouts in the regular expression the problem was discovered.
Note that the POSIX character classes do B<not> have the C<is> prefix
the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
the BSD version, which takes a pid.
=item POSIX syntax [%c %c] belongs inside character classes in regex; marked by
-<-- HERE in m/%s/
+S<<-- HERE> in m/%s/
(W regexp) The character class constructs [: :], [= =], and [. .] go
I<inside> character classes, the [] are part of the construct, for example:
/[012[:alpha:]345]/. Note that [= =] and [. .] are not currently
implemented; they are simply placeholders for future extensions and
-will cause fatal errors. The <-- HERE shows whereabouts in the regular
+will cause fatal errors. The S<<-- HERE> shows whereabouts in the regular
expression the problem was discovered. See L<perlre>.
=item POSIX syntax [. .] is reserved for future extensions in regex; marked by
-<-- HERE in m/%s/
+S<<-- HERE> in m/%s/
(F) 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: "\[."
-and ".\]". The <-- HERE shows whereabouts in the regular expression the
+and ".\]". The S<<-- HERE> shows whereabouts in the regular expression the
problem was discovered. See L<perlre>.
=item POSIX syntax [= =] is reserved for future extensions in regex; marked by
-<-- HERE in m/%s/
+S<<-- HERE> in m/%s/
(F) 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: "\[="
-and "=\]". The <-- HERE shows whereabouts in the regular expression the
+and "=\]". The S<<-- HERE> shows whereabouts in the regular expression the
problem was discovered. See L<perlre>.
=item Possible attempt to put comments in qw() list
L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
in L<perlos2>.
-=item Property '%s' is unknown in regex; marked by <-- HERE in m/%s/
+=item Property '%s' is unknown in regex; marked by S<<-- HERE> in m/%s/
(F) The named property which you specified via C<\p> or C<\P> is not one
known to Perl. Perhaps you misspelled the name? See
case of that character is not in Latin1, in that locale it doesn't
change when upper cased.
-=item Quantifier follows nothing in regex; marked by <-- HERE in m/%s/
+=item push on reference is experimental
+
+(S experimental::autoderef) C<push> with a scalar argument is experimental and
+may change or be removed in a future Perl version. If you want to take
+the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
+=item Quantifier follows nothing in regex; marked by S<< <-- HERE in m/%s/ >>
(F) You started a regular expression with a quantifier. Backslash it if
-you meant it literally. The <-- HERE shows whereabouts in the regular
+you meant it literally. The S<<-- HERE> shows whereabouts in the regular
expression the problem was discovered. See L<perlre>.
-=item Quantifier in {,} bigger than %d in regex; marked by <-- HERE in m/%s/
+=item Quantifier in {,} bigger than %d in regex; marked by S<<-- HERE> in
+m/%s/
(F) There is currently a limit to the size of the min and max values of
-the {min,max} construct. The <-- HERE shows whereabouts in the regular
+the {min,max} construct. The S<<-- HERE> shows whereabouts in the regular
expression the problem was discovered. See L<perlre>.
=item Quantifier {n,m} with n > m can't match in regex
-=item Quantifier {n,m} with n > m can't match in regex; marked by <-- HERE in m/%s/
+=item Quantifier {n,m} with n > m can't match in regex; marked by
+S<<-- HERE> in m/%s/
(W regexp) Minima should be less than or equal to maxima. If you really
want your regexp to match something 0 times, just put {0}.
(W misc) You have attempted to weaken a reference that is already weak.
Doing so has no effect.
-=item Reference to invalid group 0 in regex; marked by <-- HERE in m/%s/
+=item Reference to invalid group 0 in regex; marked by S<<-- HERE> in m/%s/
(F) You used C<\g0> or similar in a regular expression. You may refer
to capturing parentheses only with strictly positive integers
(normal backreferences) or with strictly negative integers (relative
backreferences). Using 0 does not make sense.
-=item Reference to nonexistent group in regex; marked by <-- HERE in m/%s/
+=item Reference to nonexistent group in regex; marked by S<<-- HERE> in
+m/%s/
(F) You used something like C<\7> in your regular expression, but there are
not at least seven sets of capturing parentheses in the expression. If
The <-- HERE shows whereabouts in the regular expression the problem was
discovered.
-=item Reference to nonexistent named group in regex; marked by <-- HERE in m/%s/
+=item Reference to nonexistent named group in regex; marked by S<<-- HERE>
+in m/%s/
(F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
expression, but there is no corresponding named capturing parentheses
The <-- HERE shows whereabouts in the regular expression the problem was
discovered.
-=item Reference to nonexistent or unclosed group in regex; marked by <-- HERE
-in m/%s/
+=item Reference to nonexistent or unclosed group in regex; marked by
+S<<-- HERE> in m/%s/
(F) You used something like C<\g{-7}> in your regular expression, but there
are not at least seven sets of closed capturing parentheses in the
=item Regexp modifier "/%c" may appear a maximum of twice
-=item Regexp modifier "/%c" may not appear twice
+=item Regexp modifier "%c" may appear a maximum of twice in regex; marked
+by S<<-- HERE> in m/%s/
-(F syntax, regexp) The regular expression pattern had too many occurrences
+(F) The regular expression pattern had too many occurrences
of the specified modifier. Remove the extraneous ones.
=item Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
expression to use the modifier you want to turn on (and place it before
the minus), instead of the one you want to turn off.
+=item Regexp modifier "/%c" may not appear twice
+
+=item Regexp modifier "%c" may not appear twice in regex; marked by <--
+HERE in m/%s/
+
+(F) The regular expression pattern had too many occurrences
+of the specified modifier. Remove the extraneous ones.
+
=item Regexp modifiers "/%c" and "/%c" are mutually exclusive
-(F syntax, regexp) The regular expression pattern had more than one of these
+=item Regexp modifiers "%c" and "%c" are mutually exclusive in regex;
+marked by S<<-- HERE> in m/%s/
+
+(F) The regular expression pattern had more than one of these
mutually exclusive modifiers. Retain only the modifier that is
supposed to be there.
(W closed) The socket you're sending to got itself closed sometime
before now. Check your control flow.
-=item Sequence (? incomplete in regex; marked by <-- HERE in m/%s/
+=item Sequence (? incomplete in regex; marked by S<<-- HERE> in m/%s/
(F) A regular expression ended with an incomplete extension (?. The
-<-- HERE shows whereabouts in the regular expression the problem was
+S<<-- HERE> shows whereabouts in the regular expression the problem was
discovered. See L<perlre>.
-=item Sequence (?%s...) not implemented in regex; marked by <-- HERE in m/%s/
+=item Sequence (?%c...) not implemented in regex; marked by S<<-- HERE> in
+m/%s/
(F) A proposed regular expression extension has the character reserved
-but has not yet been written. The <-- HERE shows whereabouts in the
+but has not yet been written. The S<<-- HERE> shows whereabouts in the
regular expression the problem was discovered. See L<perlre>.
-=item Sequence (?%s...) not recognized in regex; marked by <-- HERE in m/%s/
+=item Sequence (?%s...) not recognized in regex; marked by S<<-- HERE> in
+m/%s/
-(F) You used a regular expression extension that doesn't make sense. The
-<-- HERE shows whereabouts in the regular expression the problem was
-discovered. This happens when using the C<(?^...)> construct to tell
+(F) You used a regular expression extension that doesn't make sense.
+The S<<-- HERE> shows whereabouts in the regular expression the problem was
+discovered. This may happen when using the C<(?^...)> construct to tell
Perl to use the default regular expression modifiers, and you
redundantly specify a default modifier. For other
causes, see L<perlre>.
parenthesis. Embedded parentheses aren't allowed. See
L<perlre>.
-=item Sequence \%s... not terminated in regex; marked by <-- HERE in m/%s/
+=item Sequence (?&... not terminated in regex; marked by S<<-- HERE> in
+m/%s/
+
+(F) A named reference of the form C<(?&...)> was missing the final
+closing parenthesis after the name. The S<<-- HERE> shows whereabouts
+in the regular expression the problem was discovered.
+
+=item Sequence (?%c... not terminated in regex; marked by S<<-- HERE>
+in m/%s/
+
+(F) A named group of the form C<(?'...')> or C<< (?<...>) >> was missing the final
+closing quote or angle bracket. The S<<-- HERE> shows whereabouts in the
+regular expression the problem was discovered.
+
+=item Sequence (?(%c... not terminated in regex; marked by S<<-- HERE>
+in m/%s/
+
+(F) A named reference of the form C<(?('...')...)> or C<< (?(<...>)...) >> was
+missing the final closing quote or angle bracket after the name. The
+S<<-- HERE> shows whereabouts in the regular expression the problem was
+discovered.
+
+=item Sequence \%s... not terminated in regex; marked by S<<-- HERE> in
+m/%s/
(F) The regular expression expects a mandatory argument following the escape
sequence and this has been omitted or incorrectly written.
(F) The end of the perl code contained within the {...} must be
followed immediately by a ')'.
+=item Sequence ?P=... not terminated in regex; marked by S<<-- HERE> in
+m/%s/
+
+(F) A named reference of the form C<(?P=...)> was missing the final
+closing parenthesis after the name. The S<<-- HERE> shows whereabouts
+in the regular expression the problem was discovered.
+
+=item Sequence (?R) not terminated in regex m/%s/
+
+(F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
+final parenthesis.
+
=item Server error (a.k.a. "500 Server error")
(A) This is the error message generally seen in a browser window
forget to check the return value of your socket() call? See
L<perlfunc/setsockopt>.
+=item shift on reference is experimental
+
+(S experimental::autoderef) C<shift> with a scalar argument is experimental
+and may change or be removed in a future Perl version. If you want to
+take the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
=item shm%s not implemented
(F) You don't have System V shared memory IPC on your system.
try explicitly pre-extending the array by assigning $#array = $offset.
See L<perlfunc/splice>.
+=item splice on reference is experimental
+
+(S experimental::autoderef) C<splice> with a scalar argument is experimental
+and may change or be removed in a future Perl version. If you want to
+take the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
=item Split loop
(P) The split was looping infinitely. (Obviously, a split shouldn't
Unicode characters.
=item Switch (?(condition)... contains too many branches in regex; marked by
-<-- HERE in m/%s/
+S<<-- HERE> in m/%s/
(F) A (?(condition)if-clause|else-clause) construct can have at most
two branches (the if-clause and the else-clause). If you want one or
(?(condition)(?:this|that|other)|else-clause)
-The <-- HERE shows whereabouts in the regular expression the problem
+The S<<-- HERE> shows whereabouts in the regular expression the problem
was discovered. See L<perlre>.
-=item Switch condition not recognized in regex; marked by <-- HERE in m/%s/
+=item Switch condition not recognized in regex; marked by S<<-- HERE> in
+m/%s/
+
+(F) The condition part of a (?(condition)if-clause|else-clause) construct
+is not known. The condition must be one of the following:
+
+ (1) (2) ... true if 1st, 2nd, etc., capture matched
+ (<NAME>) ('NAME') true if named capture matched
+ (?=...) (?<=...) true if subpattern matches
+ (?!...) (?<!...) true if subpattern fails to match
+ (?{ CODE }) true if code returns a true value
+ (R) true if evaluating inside recursion
+ (R1) (R2) ... true if directly inside capture group 1, 2, etc.
+ (R&NAME) true if directly inside named capture
+ (DEFINE) always false; for defining named subpatterns
-(F) If the argument to the (?(...)if-clause|else-clause) construct is
-a number, it can be only a number. The <-- HERE shows whereabouts in
-the regular expression the problem was discovered. See L<perlre>.
+The <-- HERE shows whereabouts in the regular expression the problem was
+discovered. See L<perlre>.
=item switching effective %s is not implemented
(F) While under the C<use filetest> pragma, we cannot switch the real
and effective uids or gids.
-=item %s syntax OK
-
-(F) The final summary message when a C<perl -c> succeeds.
-
=item syntax error
(F) Probably means you had a syntax error. Common reasons include:
(F) Perl could not figure out what you meant inside this construct; this
notifies you that it is giving up trying.
+=item %s syntax OK
+
+(F) The final summary message when a C<perl -c> succeeds.
+
=item sysread() on closed filehandle %s
(W closed) You tried to read from a closed filehandle.
(F) The unexec() routine failed for some reason. See your local FSF
representative, who probably put it there in the first place.
-=item Unexpected binary operator '%c' with no preceding operand in regex; marked by <-- HERE in m/%s/
+=item Unexpected binary operator '%c' with no preceding operand in regex;
+marked by S<<-- HERE> in m/%s/
(F) You had something like this:
where the C<"|"> is a binary operator with an operand on the right, but
no operand on the left.
-=item Unexpected character in regex; marked by <-- HERE in m/%s/
+=item Unexpected character in regex; marked by S<<-- HERE> in m/%s/
(F) You had something like this:
(S) exit() was called or the script otherwise finished gracefully when
C<PERL_EXIT_WARN> was set in C<PL_exit_flags>.
-=item Unexpected exit failure %u
+=item Unexpected exit failure %d
(S) An uncaught die() was called when C<PERL_EXIT_WARN> was set in
C<PL_exit_flags>.
-=item Unexpected ')' in regex; marked by <-- HERE in m/%s/
+=item Unexpected ')' in regex; marked by S<<-- HERE> in m/%s/
(F) You had something like this:
be combined with the digits, or the C<"+"> shouldn't be there, or
something like that. Perl can't figure out what was intended.
-=item Unexpected '(' with no preceding operator in regex; marked by <-- HERE in m/%s/
+=item Unexpected '(' with no preceding operator in regex; marked by
+S<<-- HERE> in m/%s/
(F) You had something like this:
=item Unicode non-character U+%X is illegal for open interchange
-(S utf8, nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
+(S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
defined by the Unicode standard to be non-characters. Those are
legal codepoints, but are reserved for internal use; so, applications
shouldn't attempt to exchange them. If you know what you are doing
=item Unicode surrogate U+%X is illegal in UTF-8
-(S utf8, surrogate) You had a UTF-16 surrogate in a context where they are
+(S surrogate) You had a UTF-16 surrogate in a context where they are
not considered acceptable. These code points, between U+D800 and
U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
internally allows all unsigned integer code points (up to the size limit
(W) You tried to use an unknown subpragma of the "re" pragma.
-=item Unknown switch condition (?(...)) in regex; marked by <-- HERE in m/%s/
+=item Unknown switch condition (?(...)) in regex; marked by S<<-- HERE> in
+m/%s/
(F) The condition part of a (?(condition)if-clause|else-clause) construct
is not known. The condition must be one of the following:
(F) You specified an unknown Unicode option. See L<perlrun> documentation
of the C<-C> switch for the list of known options.
-=item Unknown verb pattern '%s' in regex; marked by <-- HERE in m/%s/
+=item Unknown verb pattern '%s' in regex; marked by S<<-- HERE> in m/%s/
(F) You either made a typo or have incorrectly put a C<*> quantifier
after an open brace in your pattern. Check the pattern and review
module (e.g. C<use warnings 'File::Find'>), you must have loaded this
module first.
-=item Unmatched '[' in POSIX class in regex; marked by <-- HERE in m/%s/
+=item Unmatched '[' in POSIX class in regex; marked by S<<-- HERE> in m/%s/
(F) You had something like this:
(?[ [:digit:] ])
-=item Unmatched '%c' in POSIX class in regex; marked by <-- HERE in m/%s/
+=item Unmatched '%c' in POSIX class in regex; marked by S<<-- HERE> in
+m/%s/
(F) You had something like this:
(?[ [:alnum:] ])
-=item Unmatched [ in regex; marked by <-- HERE in m/%s/
+=item Unmatched [ in regex; marked by S<<-- HERE> in m/%s/
(F) The brackets around a character class must match. If you wish to
include a closing bracket in a character class, backslash it or put it
-first. The <-- HERE shows whereabouts in the regular expression the
+first. The S<<-- HERE> shows whereabouts in the regular expression the
problem was discovered. See L<perlre>.
-=item Unmatched ( in regex; marked by <-- HERE in m/%s/
+=item Unmatched ( in regex; marked by S<<-- HERE> in m/%s/
-=item Unmatched ) in regex; marked by <-- HERE in m/%s/
+=item Unmatched ) in regex; marked by S<<-- HERE> in m/%s/
(F) Unbackslashed parentheses must always be balanced in regular
expressions. If you're a vi user, the % key is valuable for finding
-the matching parenthesis. The <-- HERE shows whereabouts in the
+the matching parenthesis. The S<<-- HERE> shows whereabouts in the
regular expression the problem was discovered. See L<perlre>.
=item Unmatched right %s bracket
somehow, or insert an underbar into it. You might also declare it as a
subroutine.
-=item Unrecognized character %s; marked by <-- HERE after %s near column %d
+=item Unrecognized character %s; marked by S<<-- HERE> after %s near column
+%d
(F) The Perl parser has no idea what to do with the specified character
in your Perl script (or eval) near the specified column. Perhaps you tried
to run a compressed script, a binary program, or a directory as a Perl program.
-=item Unrecognized escape \%c in character class in regex; marked by <-- HERE in m/%s/
+=item Unrecognized escape \%c in character class in regex; marked by
+S<<-- HERE> in m/%s/
(F) You used a backslash-character combination which is not
recognized by Perl inside character classes. This is a fatal
error when the character class is used within C<(?[ ])>.
=item Unrecognized escape \%c in character class passed through in regex;
-marked by <-- HERE in m/%s/
+marked by S<<-- HERE> in m/%s/
(W regexp) You used a backslash-character combination which is not
recognized by Perl inside character classes. The character was
understood literally, but this may change in a future version of Perl.
-The <-- HERE shows whereabouts in the regular expression the
+The S<<-- HERE> shows whereabouts in the regular expression the
escape was discovered.
=item Unrecognized escape \%c passed through
recognized by Perl. The character was understood literally, but this may
change in a future version of Perl.
-=item Unrecognized escape \%s passed through in regex; marked by <-- HERE in m/%s/
+=item Unrecognized escape \%s passed through in regex; marked by
+S<<-- HERE> in m/%s/
(W regexp) You used a backslash-character combination which is not
recognized by Perl. The character(s) were understood literally, but
-this may change in a future version of Perl. The <-- HERE shows
+this may change in a future version of Perl. The S<<-- HERE> shows
whereabouts in the regular expression the escape was discovered.
=item Unrecognized signal name "%s"
think you didn't do that, check the #! line to see if it's supplying the
bad switch on your behalf.)
+=item unshift on reference is experimental
+
+(S experimental::autoderef) C<unshift> with a scalar argument is experimental
+and may change or be removed in a future Perl version. If you want to
+take the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
=item Unsuccessful %s on filename containing newline
(W newline) A file operation was attempted on a filename, and that
<<"foo"
-=item Unterminated \g... pattern in regex; marked by <-- HERE in m/%s/
+=item Unterminated \g... pattern in regex; marked by S<<-- HERE> in m/%s/
-=item Unterminated \g{...} pattern in regex; marked by <-- HERE in m/%s/
+=item Unterminated \g{...} pattern in regex; marked by S<<-- HERE> in m/%s/
(F) In a regular expression, you had a C<\g> that wasn't followed by a
proper group reference. In the case of C<\g{>, the closing brace is
not finding it. Chances are you left some needed parentheses out
earlier in the line, and you really meant a "less than".
-=item Unterminated verb pattern argument in regex; marked by <-- HERE in m/%s/
+=item Unterminated verb pattern argument in regex; marked by S<<-- HERE> in
+m/%s/
(F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
the pattern with a C<)>. Fix the pattern and retry.
-=item Unterminated verb pattern in regex; marked by <-- HERE in m/%s/
+=item Unterminated verb pattern in regex; marked by S<<-- HERE> in m/%s/
(F) You used a pattern of the form C<(*VERB)> but did not terminate
the pattern with a C<)>. Fix the pattern and retry.
the subroutine returned was a temporary scalar about to
be discarded, so the assignment had no effect.
-=item Useless (?-%s) - don't use /%s modifier in regex; marked by <-- HERE in
-m/%s/
+=item Useless (?-%s) - don't use /%s modifier in regex; marked by
+S<<-- HERE> in m/%s/
(W regexp) You have used an internal modifier such as (?-o) that has no
meaning unless removed from the entire regexp:
but in fact the local() currently has no effect. This may change at
some point in the future, but in the meantime such code is discouraged.
-=item Useless (?%s) - use /%s modifier in regex; marked by <-- HERE in m/%s/
+=item Useless (?%s) - use /%s modifier in regex; marked by S<<-- HERE> in
+m/%s/
(W regexp) You have used an internal modifier such as (?o) that has no
meaning unless applied to the entire regexp:
(W misc) You have a \E in a double-quotish string without a C<\U>,
C<\L> or C<\Q> preceding it.
+=item Useless use of greediness modifier '%c' in regex; marked by S<<-- HERE> in m/%s/
+
+(W regexp) You specified something like these:
+
+ qr/a{3}?/
+ qr/b{1,1}+/
+
+The C<"?"> and C<"+"> don't have any effect, as they modify whether to
+match more or fewer when there is a choice, and by specifying to match
+exactly a given numer, there is no room left for a choice.
+
=item Useless use of %s in void context
(W void) You did something without a side effect in a context that does
String constants that would normally evaluate to 0 or 1 are warned
about.
-=item Useless use of (?-p) in regex; marked by <-- HERE in m/%s/
+=item Useless use of (?-p) in regex; marked by S<<-- HERE> in m/%s/
(W regexp) The C<p> modifier cannot be turned off once set. Trying to do
so is futile.
(D deprecated) You are now encouraged to use the explicitly quoted
form if you wish to use an empty line as the terminator of the here-document.
-=item Use of comma-less variable list is deprecated
-
-(D deprecated) The values you give to a format should be
-separated by commas, not just aligned on a line.
-
=item Use of chdir('') or chdir(undef) as chdir() deprecated
(D deprecated) chdir() with no arguments is documented to change to
use the /g modifier. Currently, /c is meaningful only when /g is
used. (This may change in the future.)
+=item Use of comma-less variable list is deprecated
+
+(D deprecated) The values you give to a format should be
+separated by commas, not just aligned on a line.
+
=item Use of each() on hash after insertion without resetting hash iterator results in undefined behavior
(S internal) The behavior of C<each()> after insertion is undefined;
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.
-=item Use of literal control characters in variable names is deprecated
-
-(D deprecated) Using literal control characters in the source to refer
-to the ^FOO variables, like C<$^X> and C<${^GLOBAL_PHASE}> is now
-deprecated. This only affects code like C<$\cT>, where \cT is a control in
-the source code: C<${"\cT"}> and C<$^T> remain valid.
-
=item Use of %s in printf format not supported
(F) You attempted to use a feature of printf that is accessible from
generally because there's a better way to do it, and also because the
old way has bad side effects.
+=item Use of literal control characters in variable names is deprecated
+
+(D deprecated) Using literal control characters in the source to refer
+to the ^FOO variables, like C<$^X> and C<${^GLOBAL_PHASE}> is now
+deprecated. This only affects code like C<$\cT>, where \cT is a control in
+the source code: C<${"\cT"}> and C<$^T> remain valid.
+
=item Use of -l on filehandle%s
(W io) A filehandle represents an opened file, and when you opened the file
C<concatenation (.)> operator, even though there is no C<.> in
your program.
-=item Use \x{...} for more than two hex characters in regex; marked by <-- HERE in m/%s/
+=item Use \x{...} for more than two hex characters in regex; marked by
+S<<-- HERE> in m/%s/
(F) In a regular expression, you said something like
and will be removed in a future version.
=item Using just the first character returned by \N{} in character class in
-regex; marked by <-- HERE in m/%s/
+regex; marked by S<<-- HERE> in m/%s/
(W regexp) A charnames handler may return a sequence of more than one
character. Currently all but the first one are discarded when used in
=item UTF-16 surrogate U+%X
-(S utf8, surrogate) You had a UTF-16 surrogate in a context where they are
+(S surrogate) You had a UTF-16 surrogate in a context where they are
not considered acceptable. These code points, between U+D800 and
U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
internally allows all unsigned integer code points (up to the size limit
longer than 1024 characters. The return value has been truncated to
1024 characters.
+=item values on reference is experimental
+
+(S experimental::autoderef) C<values> with a scalar argument is experimental
+and may change or be removed in a future Perl version. If you want to
+take the risk of using this feature, simply disable this warning:
+
+ no warnings "experimental::autoderef";
+
=item Variable "%s" is not available
(W closure) During compilation, an inner named subroutine or eval is
(S printf) The %vd (s)printf format does not support version objects
with alpha parts.
-=item Verb pattern '%s' has a mandatory argument in regex; marked by <-- HERE
-in m/%s/
+=item Verb pattern '%s' has a mandatory argument in regex; marked by
+S<<-- HERE> in m/%s/
(F) You used a verb pattern that requires an argument. Supply an
argument or check that you are using the right verb.
-=item Verb pattern '%s' may not have an argument in regex; marked by <-- HERE
-in m/%s/
+=item Verb pattern '%s' may not have an argument in regex; marked by
+S<<-- HERE> in m/%s/
(F) You used a verb pattern that is not allowed an argument. Remove the
argument or check that you are using the right verb.
not get any randomness out of your system. This usually indicates
Something Very Wrong.
+=item Zero length \N{} in regex; marked by S<<-- HERE> in m/%s/
+
+(F) Named Unicode character escapes C<(\N{...})> may return a zero-length
+sequence. Such an escape was used in an extended character class, i.e.
+C<(?[...])>, which is not permitted. Check that the correct escape has
+been used, and the correct charnames handler is in scope. The S<<-- HERE>
+shows whereabouts in the regular expression the problem was discovered.
+
=back
=head1 SEE ALSO
https://perl5.git.perl.org / perl5.git / blobdiff