=item Character following "\c" must be ASCII
(F)(W deprecated, syntax) In C<\cI<X>>, I<X> must be an ASCII character.
-It is planned to make this fatal in all instances in Perl 5.18. In the
-cases where it isn't fatal, the character this evaluates to is
+It is planned to make this fatal in all instances in Perl v5.20. In
+the cases where it isn't fatal, the character this evaluates to is
derived by exclusive or'ing the code point of this character with 0x40.
-Note that non-alphabetic ASCII characters are discouraged here as well.
+Note that non-alphabetic ASCII characters are discouraged here as well,
+and using non-printable ones will be deprecated starting in v5.18.
=item Character in 'C' format wrapped in pack
(D deprecated, syntax) The C<\cI<X>> construct is intended to be a way
to specify non-printable characters. You used it with a "{" which
evaluates to ";", which is printable. It is planned to remove the
-ability to specify a semi-colon this way in Perl 5.18. Just use a
+ability to specify a semi-colon this way in Perl 5.20. Just use a
semi-colon or a backslash-semi-colon without the "\c".
=item "\c%c" is more clearly written simply as "%s"
(F) The CORE:: namespace is reserved for Perl keywords.
+=item Corrupted regexp opcode %d > %d
+
+(P) This is either an error in Perl, or, if you're using
+one, your L<custom regular expression engine|perlreapi>. If not the
+latter, report the problem through the L<perlbug> utility.
+
=item corrupted regexp pointers
(P) The regular expression engine got confused by what the regular
named "elseif" for the class returned by the following block. This is
unlikely to be what you want.
-=item Empty %s
+=item Empty \%c{} in regex; marked by <-- 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
(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/
+
+(F) You wrote something like
+
+ (?13
+
+to denote a capturing group of the form
+L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>,
+but omitted the C<")">.
+
=item Experimental "%s" subs not enabled
(F) To use lexical subs, you must first enable them:
forget to check the return value of your socket() call? See
L<perlfunc/getsockopt>.
+=item given is experimental
+
+(S experimental::smartmatch) C<given> depends on smartmatch, which
+is experimental, so its behavior may change or even be removed
+in any future release of perl. See the explanation under
+L<perlsyn/Experimental Details on given and when>.
+
=item Global symbol "%s" requires explicit package name
(F) You've said "use strict" or "use strict vars", which indicates
(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/
+
+(F) You wrote something like
+
+ (?+foo)
+
+The C<"+"> is valid only when followed by digits, indicating a
+capturing group. See
+L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
+
=item Illegal switch in PERL5OPT: -%c
(X) The PERL5OPT environment variable may only be used to set the
=item Incomplete expression within '(?[ ])' in regex; marked by <-- HERE in m/%s/
-(F)
-There was a syntax error within the C<(?[ ])>. This can happen if the
+(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
too many or few operands for the number of operators. Perl is not smart
enough to give you a more precise indication as to what is wrong.
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/
+
+(D regexp, deprecated) The two-character sequence C<"(?"> in
+this context in a regular expression pattern should be an
+indivisible token, with nothing intervening between the C<"(">
+and the C<"?">, but you separated them. Due to an accident of
+implementation, this prohibition was not enforced, but we do
+plan to forbid it in a future Perl version. This message
+serves as giving you fair warning of this pending change.
+
=item Integer overflow in format string for %s
(F) The indexes and widths specified in the format string of C<printf()>
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/
+
+(D regexp, deprecated) The two-character sequence C<"(*"> in
+this context in a regular expression pattern should be an
+indivisible token, with nothing intervening between the C<"(">
+and the C<"*">, but you separated them. Due to an accident of
+implementation, this prohibition was not enforced, but we do
+plan to forbid it in a future Perl version. This message
+serves as giving you fair warning of this pending change.
+
=item ioctl is not implemented
(F) Your machine apparently doesn't implement ioctl(), which is pretty
(?[ [ \007 8 ] ]) # Clearer
The maximum number this construct can express is C<\777>. If you
-need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes>
-instead. If you meant two separate things, you need to separate them
+need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes> instead. If you meant
+two separate things, you need to separate them:
(?[ [ \7776 ] ]) # Syntax error!
(?[ [ \o{7776} ] ]) # One meaning
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/
+
+(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/
+
+(F) In a regular expression, there was a non-octal character where
+an octal one was expected, like
+
+ (?[ [ \o{1278} ] ])
+
+=item Non-octal character '%c'. Resolved as "%s"
+
+(W digit) In parsing an octal numeric constant, a character was
+unexpectedly encountered that isn't octal. The resulting value
+is as indicated.
+
=item "no" not allowed in expression
(F) The "no" keyword is recognized and executed at compile time, and
returns no useful value. See L<perlmod>.
+=item Non-string passed as bitmask
+
+(W misc) A number has been passed as a bitmask argument to select().
+Use the vec() function to construct the file descriptor bitmasks for
+select. See L<perlfunc/select>.
+
=item No output file after > on command line
(F) An error peculiar to VMS. Perl handles its own command line
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/
+
+(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
+to run-time the calculation of what it should evaluate to, and it is
+regex compile-time only.
+
=item no UTC offset information; assuming local time is UTC
(S) A warning peculiar to VMS. Perl was unable to find the local
F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
need to be added to UTC to get local time.
-=item Non-hex character in regex; marked by <-- 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 '%c'. Resolved as "%s"
-
-(W digit) In parsing an octal numeric constant, a character was
-unexpectedly encountered that isn't octal. The resulting value
-is as indicated.
-
-=item Non-octal character in regex; marked by <-- HERE in m/%s/
-
-(F)
-In a regular expression, there was a non-octal character where
-an octal one was expected, like
-
- (?[ [ \o{1278} ] ])
-
-=item Non-string passed as bitmask
-
-(W misc) A number has been passed as a bitmask argument to select().
-Use the vec() function to construct the file descriptor bitmasks for
-select. See L<perlfunc/select>.
-
-=item (?[...]) not valid in locale in regex; marked by <-- 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 to run-time the calculation of what it should evaluate to, and
-it is regex compile-time only.
-
=item Null filename used
(F) You can't require the null filename, especially because on many
=item Operand with no preceding operator in regex; marked by <-- HERE in m/%s/
-(F)
-You wrote something like
+(F) You wrote something like
(?[ \p{Digit} \p{Thai} ])
(D regexp, deprecated) You used a regular expression with
case-insensitive matching, and there is a bug in Perl in which the
-built-in regular expression folding rules are not accurate. This may
-lead to incorrect results. Please report this as a bug using the
+built-in regular expression folding rules are not accurate. This
+may lead to incorrect results. Please report this as a bug using the
L<perlbug> utility. (This message is marked deprecated, so that it by
default will be turned-on.)
Maybe the code needs to be updated, or maybe it is simply
wrong and the version check should just be removed.
+=item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only partially set
+
+(W) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
+contained a non hex character. This could mean you are not using the
+hash seed you think you are.
+
=item perl: warning: Setting locale failed.
(S) The whole warning message will look something like:
time you run Perl. How to really fix the problem can be found in
L<perllocale> section B<LOCALE PROBLEMS>.
-=item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only
-partially set
+=item perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
-(W) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
-contained a non hex character. This could mean your hash randomization
-is not being set correctly.
+(W) Perl was run with the environment variable PERL_PERTURB_KEYS defined
+but containing an unexpected value. The legal values of this setting
+are as follows.
+
+ Numeric | String | Result
+ --------+---------------+-----------------------------------------
+ 0 | NO | Disables key traversal randomization
+ 1 | RANDOM | Enables full key traversal randomization
+ 2 | DETERMINISTIC | Enables repeatable key traversal randomization
+
+Both numeric and string values are accepted, but note that string values are
+case sensitive. The default for this setting is "RANDOM" or 1.
=item pid %x not a child
=item Property '%s' is unknown in regex; marked by <-- HERE in m/%s/
-(F)
-The named property which you specified via C<\p> or C<\P> is not one
+(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
L<perluniprops/Properties accessible through \p{} and \P{}>
-for a complete list of available official properties. If it is a
-L<user-defined property|perlunicode/User-Defined Character Properties>
+for a complete list of available official
+properties. If it is a L<user-defined property|perlunicode/User-Defined Character Properties>
it must have been defined by the time the regular expression is
compiled.
the {min,max} construct. The <-- 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/
+
+(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}.
+
=item Quantifier unexpected on zero-length expression in regex; marked by <--
HERE in m/%s/
The <-- HERE shows whereabouts in the regular expression the problem was
discovered.
-=item Quantifier {n,m} with n > m can't match in regex; marked by <-- 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}.
-
=item Range iterator outside integer range
(F) One (or both) of the numeric arguments to the range operator ".."
(F) The end of the perl code contained within the {...} must be
followed immediately by a ')'.
-=item Z<>500 Server error
-
-See Server error.
-
-=item Server error
+=item Server error (a.k.a. "500 Server error")
(A) This is the error message generally seen in a browser window
when trying to run a CGI program (including SSI) over the web. The
=item Smart matching a non-overloaded object breaks encapsulation
(F) You should not use the C<~~> operator on an object that does not
-overload it: Perl refuses to use the object's underlying structure for
-the smart match.
+overload it: Perl refuses to use the object's underlying structure
+for the smart match.
+
+=item Smartmatch is experimental
+
+(S experimental::smartmatch) This warning is emitted if you
+use the smartmatch (C<~~>) operator. This is currently an experimental
+feature, and its details are subject to change in future releases of
+Perl. Particularly, its current behavior is noticed for being
+unnecessarily complex and unintuitive, and is very likely to be
+overhauled.
=item sort is now a reserved word
a perl4 interpreter, especially if the next 2 tokens are "use strict"
or "my $var" or "our $var".
+=item Syntax error in (?[...]) in regex m/%s/
+
+(F) Perl could not figure out what you meant inside this construct; this
+notifies you that it is giving up trying.
+
=item sysread() on closed filehandle %s
(W closed) You tried to read from a closed filehandle.
(W unopened) You tried to read from a filehandle that was never opened.
-=item Syntax error in (?[...]) in regex m/%s/
-
-(F)
-Perl could not figure out what you meant inside this construct; this
-notifies you that it is giving up trying.
-
=item System V %s is not implemented on this machine
(F) You tried to do something with a function beginning with "sem",
will continue to pretend that it is. And if you quote me on that, I
will deny it.
+=item The %s feature is experimental
+
+(S experimental) This warning is emitted if you enable an experimental
+feature via C<use feature>. Simply suppress the warning if you want
+to use the feature, but know that in doing so you are taking the risk
+of using an experimental feature which may change or be removed in a
+future Perl version:
+
+ no warnings "experimental::lexical_subs";
+ use feature "lexical_subs";
+
+=item The %s function is unimplemented
+
+(F) The function indicated isn't implemented on this architecture,
+according to the probings of Configure.
+
=item The lexical_subs feature is experimental
(S experimental::lexical_subs) This warning is emitted if you
no warnings "experimental::regex_sets";
-=item The %s function is unimplemented
-
-(F) The function indicated isn't implemented on this architecture, according
-to the probings of Configure.
-
=item The stat preceding %s wasn't an lstat
(F) It makes no sense to test the current stat buffer for symbolic
target of the change to
%ENV which produced the warning.
+=item This Perl has not been built with support for randomized hash key traversal but something called Perl_hv_rand_set().
+
+(F) Something has attempted to use an internal API call which
+depends on Perl being compiled with the default support for randomized hash
+key traversal, but this Perl has been compiled without it. You should
+report this warning to the relevant upstream party, or recompile perl
+with default options.
+
=item thread failed to start: %s
(W threads)(S) The entry point function of threads->create() failed for some reason.
(F) The unexec() routine failed for some reason. See your local FSF
representative, who probably put it there in the first place.
-=item Unexpected '(' with no preceding operator in regex; marked by <-- HERE in m/%s/
-
-(F)
-You had something like this:
-
- (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
-
-There should be an operator before the C<"(">, as there's no indication
-as to how the digits are to be combined with the characters in the Lao
-and Thai scripts.
-
-=item Unexpected ')' in regex; marked by <-- HERE in m/%s/
-
-(F)
-You had something like this:
-
- (?[ ( \p{Digit} + ) ])
-
-The C<")"> is out-of-place. Something apparently was supposed to 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 binary operator '%c' with no preceding operand in regex; marked by <-- HERE in m/%s/
-(F)
-You had something like this:
+(F) You had something like this:
(?[ | \p{Digit} ])
=item Unexpected character in regex; marked by <-- HERE in m/%s/
-(F)
-You had something like this:
+(F) You had something like this:
(?[ z ])
(P) When compiling a subroutine call in lvalue context, Perl failed an
internal consistency check. It encountered a malformed op tree.
+=item Unexpected ')' in regex; marked by <-- HERE in m/%s/
+
+(F) You had something like this:
+
+ (?[ ( \p{Digit} + ) ])
+
+The C<")"> is out-of-place. Something apparently was supposed to
+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/
+
+(F) You had something like this:
+
+ (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
+
+There should be an operator before the C<"(">, as there's
+no indication as to how the digits are to be combined
+with the characters in the Lao and Thai scripts.
+
=item Unicode non-character U+%X is illegal for open interchange
(S utf8, nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
came from. If you really really know what you are doing you can turn
off this warning by C<no warnings 'surrogate';>.
-=item Unknown BYTEORDER
-
-(F) There are no byte-swapping functions for a machine with this byte
-order.
-
=item Unknown charname '%s'
(F) The name you used inside C<\N{}> is unknown to Perl. Check the
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/
+
+(F) You had something like this:
+
+ (?[ [:digit: ])
+
+That should be written:
+
+ (?[ [:digit:] ])
+
=item Unmatched '%c' in POSIX class in regex; marked by <-- HERE in m/%s/
-You had something like this:
+(F) You had something like this:
(?[ [:alnum] ])
first. The <-- HERE shows whereabouts in the regular expression the
problem was discovered. See L<perlre>.
-=item Unmatched '[' in POSIX class in regex; marked by <-- HERE in m/%s/
-
-(F)
-You had something like this:
-
- (?[ [:digit: ])
-
-That should be written:
-
- (?[ [:digit:] ])
-
=item Unmatched ( in regex; marked by <-- HERE in m/%s/
=item Unmatched ) in regex; marked by <-- HERE in m/%s/
=item Unrecognized escape \%c in character class in regex; marked by <-- 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<(?[ ])>.
+(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/
<<"foo"
+=item Unterminated \g... pattern in regex; marked by <-- HERE in m/%s/
+
=item Unterminated \g{...} pattern in regex; marked by <-- HERE in m/%s/
-(F) You missed a close brace on a \g{..} pattern (group reference) in
-a regular expression. Fix the pattern and retry.
+(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
+missing; otherwise the C<\g> must be followed by an integer. Fix the
+pattern and retry.
=item Unterminated <> operator
You probably meant to use C<$]> instead. C<$[> is the base for indexing
arrays. C<$]> is the Perl version number in decimal.
-=item Use \\x{...} for more than two hex characters in regex; marked by <-- HERE in m/%s/
-
-(F)
-In a regular expression, you said something like
-
- (?[ [ \xBEEF ] ])
-
-Perl isn't sure if you meant this
-
- (?[ [ \x{BEEF} ] ])
-
-or if you meant this
-
- (?[ [ \x{BE} E F ] ])
-
-You need to add either braces or blanks to disambiguate.
-
=item Useless assignment to a temporary
(W misc) You assigned to an lvalue subroutine, but what
s[foo[a-z]bar][baz]
The backslashes have no effect when a regular expression pattern is
-delimitted by C<{}>, C<[]>, or C<()>, which ordinarily are
+delimited by C<{}>, C<[]>, or C<()>, which ordinarily are
metacharacters, and the delimiters are also used, paired, within the
interior of the pattern. It is planned that a future Perl release will
change the meaning of constructs like these so that the backslashes
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/
+
+(W regexp) The C<p> modifier cannot be turned off once set. Trying to do
+so is futile.
+
=item Useless use of "re" pragma
(W) You did C<use re;> without any arguments. That isn't very useful.
use the /g modifier. Currently, /c is meaningful only when /g is
used. (This may change in the future.)
+=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; it may
+skip items, or visit items more than once. Consider using C<keys()> instead
+of C<each()>.
+
=item Use of := for an empty attribute list is not allowed
(F) The construction C<my $x := 42> used to parse as equivalent to
the name of the variable (if any) that was undefined. In some cases
it cannot do this, so it also tells you what operation you used the
undefined value in. Note, however, that perl optimizes your program
-anid the operation displayed in the warning may not necessarily appear
+and the operation displayed in the warning may not necessarily appear
literally in your program. For example, C<"that $foo"> is usually
optimized into C<"that " . $foo>, and the warning will refer to the
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/
+
+(F) In a regular expression, you said something like
+
+ (?[ [ \xBEEF ] ])
+
+Perl isn't sure if you meant this
+
+ (?[ [ \x{BEEF} ] ])
+
+or if you meant this
+
+ (?[ [ \x{BE} E F ] ])
+
+You need to add either braces or blanks to disambiguate.
+
=item Using a hash as a reference is deprecated
(D deprecated) You tried to use a hash as a reference, as in
So put in parentheses to say what you really mean.
+=item when is experimental
+
+(S experimental::smartmatch) C<when> depends on smartmatch, which is
+experimental. Additionally, it has several special cases that may
+not be immediately obvious, and their behavior may change or
+even be removed in any future release of perl. See the explanation
+under L<perlsyn/Experimental Details on given and when>.
+
=item Wide character in %s
(S utf8) Perl met a wide character (>255) when it wasn't expecting
=item %s "\x%X" does not map to Unicode
-(F) When reading in different encodings, Perl tries to map everything
-into Unicode characters. The bytes you read in are not legal in
-this encoding. For example
+(F) When reading in different encodings, Perl tries to map
+everything into Unicode characters. The bytes you read in
+are not legal in this encoding. For example
utf8 "\xE4" does not map to Unicode
=item Your random numbers are not that random
-(F) When trying to initialise the random seed for hashes, Perl could
+(F) When trying to initialize the random seed for hashes, Perl could
not get any randomness out of your system. This usually indicates
Something Very Wrong.
https://perl5.git.perl.org / perl5.git / blobdiff