C</^[a-zA-Z]*[0-9]*\z/>. See L<perlop/Auto-increment and
Auto-decrement> for details.
-=item Array @%s missing the @ in argument %d of %s()
-
-(D deprecated) Really old Perl let you omit the @ on array names in some
-spots. This is now heavily deprecated.
-
-=item A sequence of multiple spaces in a charnames alias definition is deprecated
-
-(D deprecated) You defined a character name which had multiple space
-characters in a row. Change them to single spaces. Usually these
-names are defined in the C<:alias> import argument to C<use charnames>, but
-they could be defined by a translator installed into C<$^H{charnames}>.
-See L<charnames/CUSTOM ALIASES>.
-
=item assertion botched: %s
(X) The malloc package that comes with Perl had an internal failure.
must either both be scalars or both be lists. Otherwise Perl won't
know which context to supply to the right side.
+=item <> at require-statement should be quotes
+
+(F) You wrote C<< require <file> >> when you should have written
+C<require 'file'>.
+
=item Attempt to access disallowed key '%s' in a restricted hash
(F) The failing code has attempted to get or set a key which is not in
(W unopened) You tried binmode() on a filehandle that was never opened.
Check your control flow and number of arguments.
-=item "\b{" is deprecated; use "\b\{" or "\b[{]" instead in regex; marked
-by S<<-- HERE> in m/%s/
-
-=item "\B{" is deprecated; use "\B\{" or "\B[{]" instead in regex; marked
-by S<<-- HERE> in m/%s/
-
-(D deprecated) Use of an unescaped "{" immediately following
-a C<\b> or C<\B> is now deprecated so as to reserve its use for Perl
-itself in a future release. You can either precede the brace
-with a backslash, or enclose it in square brackets; the latter
-is the way to go if the pattern delimiters are C<{}>.
-
=item Bit vector size > 32 non-portable
(W portable) Using bit vector sizes larger than 32 is non-portable.
though, because the inner curlies will be considered a block that loops
once. See L<perlfunc/next>.
-=item Can't open %s
-
-(F) You tried to run a perl built with MAD support with
-the PERL_XMLDUMP environment variable set, but the file
-named by that variable could not be opened.
-
=item Can't open %s: %s
(S inplace) The implicit opening of a file through use of the C<< <> >>
(F) You tried to call perl with the B<-m> switch, but you put something
other than "=" after the module name.
+=item Can't use a hash as a reference
+
+(F) You tried to use a hash as a reference, as in
+C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl
+<= 5.22.0 used to allow this syntax, but shouldn't
+have. This was deprecated in perl 5.6.1.
+
+=item Can't use an array as a reference
+
+(F) You tried to use an array as a reference, as in
+C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.22.0
+used to allow this syntax, but shouldn't have. This
+was deprecated in perl 5.6.1.
+
=item Can't use anonymous symbol table for method lookup
(F) The internal routine that does method lookup was handed a symbol
byte-order at the same time, so this combination of modifiers is not
allowed. See L<perlfunc/pack>.
+=item Can't use 'defined(@array)' (Maybe you should just omit the defined()?)
+
+(F) defined() is not useful on arrays because it
+checks for an undefined I<scalar> value. If you want to see if the
+array is empty, just use C<if (@array) { # not empty }> for example.
+
+=item Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)
+
+(F) C<defined()> is not usually right on hashes.
+
+Although C<defined %hash> is false on a plain not-yet-used hash, it
+becomes true in several non-obvious circumstances, including iterators,
+weak references, stash names, even remaining true after C<undef %hash>.
+These things make C<defined %hash> fairly useless in practice, so it now
+generates a fatal error.
+
+If a check for non-empty is what you wanted then just put it in boolean
+context (see L<perldata/Scalar values>):
+
+ if (%hash) {
+ # not empty
+ }
+
+If you had C<defined %Foo::Bar::QUUX> to check whether such a package
+variable exists then that's never really been reliable, and isn't
+a good way to enquire about the features of a package, or whether
+it's loaded, etc.
+
=item Can't use %s for loop variable
(F) Only a simple scalar variable may be used as a loop variable on a
with an assignment operator, which implies modifying the value itself.
Perhaps you need to copy the value to a temporary, and repeat that.
-=item Character following "\c" must be ASCII
+=item Character following "\c" must be printable ASCII
-(F)(D 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 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.
+(F) In C<\cI<X>>, I<X> must be a printable (non-control) ASCII character.
-Note that non-alphabetic ASCII characters are discouraged here as well,
-and using non-printable ones will be deprecated starting in v5.18.
+Note that ASCII characters that don't map to control characters are
+discouraged, and will generate the warning (when enabled)
+L</""\c%c" is more clearly written simply as "%s"">.
=item Character in 'C' format wrapped in pack
unpack("s", "\x{f3}b")
+=item charnames alias definitions may not contain a sequence of multiple spaces
+
+(F) You defined a character name which had multiple space characters
+in a row. Change them to single spaces. Usually these names are
+defined in the C<:alias> import argument to C<use charnames>, but they
+could be defined by a translator installed into C<$^H{charnames}>. See
+L<charnames/CUSTOM ALIASES>.
+
+=item charnames alias definitions may not contain trailing white-space
+
+(F) You defined a character name which ended in a space
+character. Remove the trailing space(s). Usually these names are
+defined in the C<:alias> import argument to C<use charnames>, but they
+could be defined by a translator installed into C<$^H{charnames}>.
+See L<charnames/CUSTOM ALIASES>.
+
+=item \C is deprecated in regex; marked by <-- HERE in m/%s/
+
+(D deprecated, regexp) The \C character class is deprecated, and will
+become a compile-time error in a future release of perl (tentatively
+v5.24). This construct allows you to match a single byte of what makes up
+a multi-byte single UTF8 character, and breaks encapsulation. It is
+currently also very buggy. If you really need to process the individual
+bytes, you probably want to convert your string to one where each
+underlying byte is stored as a character, with utf8::encode().
+
=item "\c%c" is more clearly written simply as "%s"
(W syntax) The C<\cI<X>> construct is intended to be a way to specify
=item %s: Command not found
(A) You've accidentally run your script through B<csh> or another shell
-shell instead of Perl. Check the #! line, or manually feed your script
-into Perl yourself. The #! line at the top of your file could look like
+instead of Perl. Check the #! line, or manually feed your script into
+Perl yourself. The #! line at the top of your file could look like
#!/usr/bin/perl -w
(F) The parser found inconsistencies while attempting to define an
overloaded constant. Perhaps you forgot to load the corresponding
-L<overload> pragma?.
+L<overload> pragma?
=item Constant is not %s reference
This threshold can be changed from 100, by recompiling the F<perl> binary,
setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
-=item defined(@array) is deprecated
-
-(D deprecated) defined() is not usually useful on arrays because it
-checks for an undefined I<scalar> value. If you want to see if the
-array is empty, just use C<if (@array) { # not empty }> for example.
-
-=item defined(%hash) is deprecated
-
-(D deprecated) C<defined()> is not usually right on hashes and has been
-discouraged since 5.004.
-
-Although C<defined %hash> is false on a plain not-yet-used hash, it
-becomes true in several non-obvious circumstances, including iterators,
-weak references, stash names, even remaining true after C<undef %hash>.
-These things make C<defined %hash> fairly useless in practice.
-
-If a check for non-empty is what you wanted then just put it in boolean
-context (see L<perldata/Scalar values>):
-
- if (%hash) {
- # not empty
- }
-
-If you had C<defined %Foo::Bar::QUUX> to check whether such a package
-variable exists then that's never really been reliable, and isn't
-a good way to enquire about the features of a package, or whether
-it's loaded, etc.
-
-
=item (?(DEFINE)....) does not allow branches in regex; marked by
S<<-- HERE> in m/%s/
an invalid file specification to Perl, or you've found a case the
conversion routines don't handle. Drat.
-=item Escape literal pattern white space under /x
-
-(D deprecated) You compiled a regular expression pattern with C</x> to
-ignore white space, and you used, as a literal, one of the characters
-that Perl plans to eventually treat as white space. The character must
-be escaped somehow, or it will work differently on a future Perl that
-does treat it as white space. The easiest way is to insert a backslash
-immediately before it, or to enclose it with square brackets. This
-change is to bring Perl into conformance with Unicode recommendations.
-Here are the five characters that generate this warning:
-U+0085 NEXT LINE,
-U+200E LEFT-TO-RIGHT MARK,
-U+200F RIGHT-TO-LEFT MARK,
-U+2028 LINE SEPARATOR,
-and
-U+2029 PARAGRAPH SEPARATOR.
-
=item Eval-group in insecure regular expression
(F) Perl detected tainted data when trying to compile a regular
(F) To use subroutine signatures, you must first enable them:
- no warnings "experimental:signatures";
+ no warnings "experimental::signatures";
use feature "signatures";
sub foo ($left, $right) { ... }
not finding it. Chances are you left some needed parentheses out
earlier in the line, and you really meant a "less than".
+=item gmtime(%f) failed
+
+(W overflow) You called C<gmtime> with a number that it could not handle:
+too large, too small, or NaN. The returned value is C<undef>.
+
=item gmtime(%f) too large
(W overflow) You called C<gmtime> with a number that was larger than
to have existed already, but for some reason it didn't, and had to be
created on an emergency basis to prevent a core dump.
-=item Hash %%s missing the % in argument %d of %s()
-
-(D deprecated) Really old Perl let you omit the % on hash names in some
-spots. This is now heavily deprecated.
-
=item %s has too many errors
(F) The parser has given up trying to parse the program after 10 errors.
Further error messages would likely be uninformative.
+=item Hexadecimal float: precision loss
+
+(W overflow) The hexadecimal floating point had internally more
+digits than could be output. This can be caused by unsupported
+long double formats, or by 64-bit integers not being available
+(needed to retrieve the digits under some configurations).
+
+=item Hexadecimal float: unsupported long double format
+
+(F) You have configured Perl to use long doubles but
+the internals of the long double format are unknown,
+therefore the hexadecimal float output is impossible.
+
=item Hexadecimal number > 0xffffffff non-portable
(W portable) The hexadecimal number you specified is larger than 2**32-1
capturing group. See
L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
+=item Illegal suidscript
+
+(F) The script run under suidperl was somehow illegal.
+
=item Illegal switch in PERL5OPT: -%c
(X) The PERL5OPT environment variable may only be used to set the
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 S<<-- 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()>
operators arguments found inside the parentheses. See
L<perlop/Terms and List Operators (Leftward)>.
+=item In '(?...)', the '(' and '?' must be adjacent in regex;
+marked by S<<-- HERE> in m/%s/
+
+(F) 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
+with whitespace.
+
=item Invalid %s attribute: %s
(F) The indicated attribute for a subroutine or variable was not recognized
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;
+=item In '(*VERB...)', the '(' and '*' must be adjacent in regex;
marked by S<<-- HERE> in m/%s/
-(D regexp, deprecated) The two-character sequence C<"(*"> in
+(F) 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.
+and the C<"*">, but you separated them.
=item ioctl is not implemented
form of C<open> does not support pipes, such as C<open($pipe, '|-', @args)>.
Use the two-argument C<open($pipe, '|prog arg1 arg2...')> form instead.
+=item localtime(%f) failed
+
+(W overflow) You called C<localtime> with a number that it could not handle:
+too large, too small, or NaN. The returned value is C<undef>.
+
=item localtime(%f) too large
(W overflow) You called C<localtime> with a number that was larger
=item Missing argument in %s
-(W uninitialized) A printf-type format required more arguments than were
-supplied.
+(W missing) You called a function with fewer arguments than other
+arguments you supplied indicated would be needed.
+
+Currently only emitted when a printf-type format required more
+arguments than were supplied, but might be used in the future for
+other cases where we can statically determine that arguments to
+functions are missing, e.g. for the L<perlfunc/pack> function.
=item Missing argument to -%c
(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 or undefined argument to require
+
+(F) You tried to call require with no argument or with an undefined
+value as an argument. Require expects either a package name or a
+file-specification as an argument. See L<perlfunc/require>.
+
=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{...}>.
(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.
+declaration is also 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
+NOTE: This warning detects package symbols that have been used
+only once. This means lexical variables will never trigger this
+warning. It also means that all of the package variables $c, @c,
+%c, as well as *c, &c, sub c{}, c(), and c (the filehandle or
format) are considered the same; if a program uses $c only once
but also uses any of the others it will not trigger this warning.
Symbols beginning with an underscore and symbols using special
(F) When C<vec> is called in an lvalue context, the second argument must be
greater than or equal to zero.
+=item Negative repeat count does nothing
+
+(W numeric) You tried to execute the
+L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
+times, which doesn't make sense.
+
=item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
(F) You can't quantify a quantifier without intervening parentheses.
will be another way to do what you want that is, if not secure, at least
securable. See L<perlsec>.
+=item NO-BREAK SPACE in a charnames alias definition is deprecated
+
+(D deprecated) You defined a character name which contained a no-break
+space character. Change it to a regular space. Usually these names are
+defined in the C<:alias> import argument to C<use charnames>, but they
+could be defined by a translator installed into C<$^H{charnames}>. See
+L<charnames/CUSTOM ALIASES>.
+
=item No code specified for -%c
(F) Perl's B<-e> and B<-E> command-line options require an argument. If
F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
need to be added to UTC to get local time.
-=item Null filename used
-
-(F) You can't require the null filename, especially because on many
-machines that means the current directory! See L<perlfunc/require>.
-
=item NULL OP IN RUN
(S debugging) Some internal routine called run() with a null opcode
"Can't locate object method \"%s\" via package \"%s\"". It often means
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
+=item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
utility to report; in regex; marked by S<<-- HERE> in m/%s/
(S regexp) You used a regular expression with case-insensitive matching,
folding rules are not accurate. This may lead to incorrect results.
Please report this as a bug using the L<perlbug> utility.
+=item PerlIO layer ':win32' is experimental
+
+(S experimental::win32_perlio) The C<:win32> PerlIO layer is
+experimental. If you want to take the risk of using this layer,
+simply disable this warning:
+
+ no warnings "experimental::win32_perlio";
+
=item Perl_my_%s() not available
(F) Your platform has very uncommon byte-order and integer size,
believes it found an infinite loop in the C<@ISA> hierarchy. This is a
crude check that bails out after 100 levels of C<@ISA> depth.
+=item Redundant argument in %s
+
+(W redundant) You called a function with more arguments than other
+arguments you supplied indicated would be needed. Currently only
+emitted when a printf-type format required fewer arguments than were
+supplied, but might be used in the future for e.g. L<perlfunc/pack>.
+
=item refcnt_dec: fd %d%s
=item refcnt: fd %d%s
in Perl 5.10.0 or later that uses the // as the I<defined-or> can be
misparsed by pre-5.10.0 Perls as a non-terminated search pattern.
-=item Search pattern not terminated or ternary operator parsed as search pattern
-
-(F) The lexer couldn't find the final delimiter of a C<?PATTERN?>
-construct.
-
-The question mark is also used as part of the ternary operator (as in
-C<foo ? 0 : 1>) leading to some ambiguous constructions being wrongly
-parsed. One way to disambiguate the parsing is to put parentheses around
-the conditional expression, i.e. C<(foo) ? 0 : 1>.
-
=item seekdir() attempted on invalid dirhandle %s
(W io) The dirhandle you are doing a seekdir() on is either closed or not
interpreted as the != (numeric not equal) and ~ (1's complement)
operators: probably not what you intended.
-=item <> should be quotes
-
-(F) You wrote C<< require <file> >> when you should have written
-C<require 'file'>.
-
=item /%s/ should probably be written as "%s"
(W syntax) You have used a pattern where Perl expected to find a string,
(F) The regular expression ends with an unbackslashed backslash.
Backslash it. See L<perlre>.
-=item Trailing white-space in a charnames alias definition is deprecated
-
-(D deprecated) You defined a character name which ended in a space
-character. Remove the trailing space(s). Usually these names are
-defined in the C<:alias> import argument to C<use charnames>, but they
-could be defined by a translator installed into C<$^H{charnames}>.
-See L<charnames/CUSTOM ALIASES>.
-
=item Transliteration pattern not terminated
(F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
(A) You've accidentally run your script through B<csh> instead of Perl.
Check the #! line, or manually feed your script into Perl yourself.
+=item Unescaped left brace in regex is deprecated, passed through in regex;
+marked by <-- HERE in m/%s/
+
+(D deprecated, regexp) You used a literal C<"{"> character in a regular
+expression pattern. You should change to use C<"\{"> instead, because a
+future version of Perl (tentatively v5.26) will consider this to be a
+syntax error. 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}
+
=item unexec of %s into %s failed!
(F) The unexec() routine failed for some reason. See your local FSF
=item Unicode non-character U+%X is illegal for open interchange
(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
-you can turn off this warning by C<no warnings 'nonchar';>.
+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. An application
+may not be expecting any of these characters at all, and receiving
+them may lead to bugs. If you know what you are doing you can
+turn off this warning by C<no warnings 'nonchar';>.
+
+This is not really a "severe" error, but it is supposed to be
+raised by default even if warnings are not enabled, and currently
+the only way to do that in Perl is to mark it as serious.
=item Unicode surrogate U+%X is illegal in UTF-8
same length as the replacelist. See L<perlop> for more information
about the /d modifier.
-=item Useless use of '\'; doesn't escape metacharacter '%c'
-
-(D deprecated) You wrote a regular expression pattern something like
-one of these:
-
- m{ \x\{FF\} }x
- m{foo\{1,3\}}
- qr(foo\(bar\))
- s[foo\[a-z\]bar][baz]
-
-The interior braces, square brackets, and parentheses are treated as
-metacharacters even though they are backslashed; instead write:
-
- m{ \x{FF} }x
- m{foo{1,3}}
- qr(foo(bar))
- s[foo[a-z]bar][baz]
-
-The backslashes have no effect when a regular expression pattern is
-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
-will have an effect, so remove them from your code.
-
=item Useless use of \E
(W misc) You have a \E in a double-quotish string without a C<\U>,
untie a scalar that had had a typeglob assigned to it. If you see this
message, you must be using an older version.
-=item Use of ?PATTERN? without explicit operator is deprecated
-
-(D deprecated) You have written something like C<?\w?>, for a regular
-expression that matches only once. Starting this term directly with
-the question mark delimiter is now deprecated, so that the question mark
-will be available for use in new operators in the future. Write C<m?\w?>
-instead, explicitly using the C<m> operator: the question mark delimiter
-still invokes match-once behaviour.
-
=item Use of reference "%s" as array index
(W misc) You tried to use a reference as an array index; this probably
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
-C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl <= 5.6.1
-used to allow this syntax, but shouldn't have. It is now
-deprecated, and will be removed in a future version.
-
-=item Using an array as a reference is deprecated
-
-(D deprecated) You tried to use an array as a reference, as in
-C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.6.1 used to
-allow this syntax, but shouldn't have. It is now deprecated,
-and will be removed in a future version.
-
=item Using just the first character returned by \N{} in character class in
regex; marked by S<<-- HERE> in m/%s/
=item Variable length lookbehind not implemented in regex m/%s/
(F) Lookbehind is allowed only for subexpressions whose length is fixed and
-known at compile time. See L<perlre>.
+known at compile time. For positive lookbehind, you can use the C<\K>
+regex construct as a way to get the equivalent functionality. See
+L<perlre/(?<=pattern) \K>.
+
+There are non-obvious Unicode rules under C</i> that can match variably,
+but which you might not think could. For example, the substring C<"ss">
+can match the single character LATIN SMALL LETTER SHARP S. There are
+other sequences of ASCII characters that can match single ligature
+characters, such as LATIN SMALL LIGATURE FFI matching C<qr/ffi/i>.
+Starting in Perl v5.16, if you only care about ASCII matches, adding the
+C</aa> modifier to the regex will exclude all these non-obvious matches,
+thus getting rid of this message. You can also say C<S<use re qw(/aa)>>
+to apply C</aa> to all regular expressions compiled within its scope.
+See L<re>.
=item "%s" variable %s masks earlier declaration in same %s
=head1 SEE ALSO
-L<warnings>, L<perllexwarn>, L<diagnostics>.
+L<warnings>, L<diagnostics>.
=cut
https://perl5.git.perl.org / perl5.git / blobdiff