to check the return value of your socket() call? See
L<perlfunc/accept>.
+=item Aliasing via reference is experimental
+
+(S experimental::refaliasing) This warning is emitted if you use
+a reference constructor on the left-hand side of an assignment to
+alias one variable to another. 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::refaliasing";
+ use feature "refaliasing";
+ \$x = \$y;
+
=item Allocation too large: %x
(X) You can't allocate more than 64K on an MS-DOS machine.
didn't explicitly request the failing operation, it may be the
result of the value of the environment variable PERLIO.
-=item charnames alias definitions may not contain a sequence of multiple spaces
+=item Argument "%s" treated as 0 in increment (++)
-(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>.
+(W numeric) The indicated string was fed as an argument to the C<++>
+operator which expects either a number or a string matching
+C</^[a-zA-Z]*[0-9]*\z/>. See L<perlop/Auto-increment and
+Auto-decrement> for details.
=item assertion botched: %s
(X) A general assertion failed. The file in question must be examined.
+=item Assigned value is not a reference
+
+(F) You tried to assign something that was not a reference to an lvalue
+reference (e.g., C<\$x = $y>). If you meant to make $x an alias to $y, use
+C<\$x = \$y>.
+
+=item Assigned value is not %s reference
+
+(F) You tried to assign a reference to a reference constructor, but the
+two references were not of the same type. You cannot alias a scalar to
+an array, or an array to a hash; the two types must match.
+
+ \$x = \@y; # error
+ \@x = \%y; # error
+ $y = [];
+ \$x = $y; # error; did you mean \$y?
+
=item Assigning non-zero to $[ is no longer possible
(F) When the "array_base" feature is disabled (e.g., under C<use v5.16;>)
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
(D deprecated) You called a function whose use is deprecated. See
the function's name in L<POSIX> for details.
+=item Cannot chr %f
+
+(F) You passed an invalid number (like an infinity or not-a-number) to C<chr>.
+
+=item Cannot compress %f in pack
+
+(F) You tried compressing an infinity or not-a-number as an unsigned
+integer with BER, which makes no sense.
+
=item Cannot compress integer in pack
-(F) An argument to pack("w",...) was too large to compress. The BER
-compressed integer format can only be used with positive integers, and you
-attempted to compress Infinity or a very large number (> 1e308).
+(F) An argument to pack("w",...) was too large to compress.
+The BER compressed integer format can only be used with positive
+integers, and you attempted to compress a very large number (> 1e308).
See L<perlfunc/pack>.
=item Cannot compress negative numbers in pack
(S io) You tried to apply an encoding that did not exist to a filehandle,
either with open() or binmode().
+=item Cannot pack %f with '%c'
+
+(F) You tried converting an infinity or not-a-number to an integer,
+which makes no sense.
+
+=item Cannot printf %f with '%c'
+
+(F) You tried printing an infinity or not-a-number as a character (%c),
+which makes no sense. Maybe you meant '%s', or just stringifying it?
+
=item Cannot set tied @DB::args
(F) C<caller> tried to set C<@DB::args>, but found it tied. Tying C<@DB::args>
functioning as a class, but that package doesn't define that particular
method, nor does any of its base classes. See L<perlobj>.
+=item Can't locate object method "%s" via package "%s" (perhaps you forgot
+to load "%s"?)
+
+(F) You called a method on a class that did not exist, and the method
+could not be found in UNIVERSAL. This often means that a method
+requires a package that has not been loaded.
+
=item Can't locate package %s for @%s::ISA
(W syntax) The @ISA array contained the name of another package that
(F) Subroutines meant to be used in lvalue context should be declared as
such. See L<perlsub/"Lvalue subroutines">.
+=item Can't modify reference to %s in %s assignment
+
+(F) Only a limited number of constructs can be used as the argument to a
+reference constructor on the left-hand side of an assignment, and what
+you used was not one of them. See L<perlref/Assigning to References>.
+
+=item Can't modify reference to localized parenthesized array in list
+assignment
+
+(F) Assigning to C<\local(@array)> or C<\(local @array)> is not supported, as
+it is not clear exactly what it should do. If you meant to make @array
+refer to some other array, use C<\@array = \@other_array>. If you want to
+make the elements of @array aliases of the scalars referenced on the
+right-hand side, use C<\(@array) = @scalar_refs>.
+
+=item Can't modify reference to parenthesized hash in list assignment
+
+(F) Assigning to C<\(%hash)> is not supported. If you meant to make %hash
+refer to some other hash, use C<\%hash = \%other_hash>. If you want to
+make the elements of %hash into aliases of the scalars referenced on the
+right-hand side, use a hash slice: C<\@hash{@keys} = @those_scalar_refs>.
+
=item Can't msgrcv to read-only var
(F) The target of a msgrcv must be modifiable to be used as a receive
=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<< %$ref->{"hello"} >>. Versions of perl <= 5.6.1
-used to allow this syntax, but shouldn't have.
+C<< %foo->{"bar"} >> or C<< %$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<< @$ref->[99] >>. Versions of perl <= 5.6.1 used to
-allow this syntax, but shouldn't have.
+C<< @foo->[23] >> or C<< @$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
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
-non-printable characters. You used it for a printable one, which is better
-written as simply itself, perhaps preceded by a backslash for non-word
-characters.
+non-printable characters. You used it for a printable one, which
+is better written as simply itself, perhaps preceded by a backslash
+for non-word characters. Doing it the way you did is not portable
+between ASCII and EBCDIC platforms.
=item Cloning substitution context is unimplemented
=item %s: Command not found
(A) You've accidentally run your script through B<csh> or another 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
have some other C<(?...)> construct inside your character class. See
L<perlrecharclass/Extended Bracketed Character Classes>.
+=item Experimental aliasing via reference not enabled
+
+(F) To do aliasing via references, you must first enable the feature:
+
+ no warnings "experimental::refaliasing";
+ use feature "refaliasing";
+ \$x = \$y;
+
=item Experimental subroutine signatures not enabled
(F) To use subroutine signatures, you must first enable them:
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
+=item Global symbol "%s" requires explicit package name (did you forget to
+declare "my %s"?)
(F) You've said "use strict" or "use strict vars", which indicates
that all variables must either be lexically scoped (using "my" or "state"),
(F) The parser has given up trying to parse the program after 10 errors.
Further error messages would likely be uninformative.
+=item Having more than one /%c regexp modifier is deprecated
+
+(D deprecated, regexp) You used the indicated regular expression pattern
+modifier at least twice in a string of modifiers. It is deprecated to
+do this with this particular modifier, to allow future extensions to the
+Perl language.
+
+=item Hexadecimal float: exponent overflow
+
+(W overflow) The hexadecimal floating point has a larger exponent
+than the floating point supports.
+
+=item Hexadecimal float: exponent underflow
+
+(W overflow) The hexadecimal floating point has a smaller exponent
+than the floating point supports.
+
+=item Hexadecimal float: internal error
+
+(F) Something went horribly bad in hexadecimal float handling.
+
+=item Hexadecimal float: mantissa overflow
+
+(W overflow) The hexadecimal floating point literal had more bits in
+the mantissa (the part between the 0x and the exponent, also known as
+the fraction or the significand) than the floating point supports.
+
+=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
=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
+(W regexp) Named Unicode character escapes (C<\N{...}>) may return a
zero-length sequence. When such an escape is used in a character class
its behaviour is not well defined. Check that the correct escape has
been used, and the correct charname handler is in scope.
function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
-=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.
-
=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
=item Invalid negative number (%s) in chr
(W utf8) You passed a negative number to C<chr>. Negative numbers are
-not valid characters numbers, so it return the Unicode replacement
+not valid character numbers, so it returns the Unicode replacement
character (U+FFFD).
=item invalid option -D%c, use -D'' to see choices
=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{...}>.
(F) Lexically scoped subroutines are not yet implemented. Don't try
that yet.
+=item "my" subroutine %s can't be in a package
+
+(F) Lexically scoped subroutines aren't in a package, so it doesn't make
+sense to try to declare one with a package qualifier on the front.
+
=item "my %s" used in sort comparison
(W syntax) The package variables $a and $b are used for sort comparisons.
just mention it again somehow to suppress the message. The C<our>
declaration is also provided for this purpose.
-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
+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.
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
+=item \N{} in inverted character class or as a range end-point is 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.
+(F) Named Unicode character escapes (C<\N{...}>) may return a
+multi-character sequence. Even though a character class is
+supposed to match just one character of input, perl will match the
+whole thing correctly, except when the class is inverted (C<[^...]>),
+or the escape is the beginning or final end point of a range. The
+mathematically logical behavior for what matches when inverting
+is very different from what people expect, so we have decided to
+forbid it. Similarly unclear is what should be generated when the
+C<\N{...}> is used as one of the end points of the range, such as in
+
+ [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]
+
+What is meant here is unclear, as the C<\N{...}> escape is a sequence
+of code points, so this is made an error.
=item \N{NAME} must be resolved by the lexer in regex; marked by
S<<-- HERE> in m/%s/
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
(P) While attempting folding constants an exception other than an C<eval>
failure was caught.
-=item panic: frexp
+=item panic: frexp: %f
(P) The library function frexp() failed, making printf("%f") impossible.
=item panic: pad_free po
-(P) An invalid scratch pad offset was detected internally.
+(P) A zero scratch pad offset was detected internally. An attempt was
+made to free a target that had not been allocated to begin with.
=item panic: pad_reset curpad, %p!=%p
=item panic: pad_sv po
-(P) An invalid scratch pad offset was detected internally.
+(P) A zero scratch pad offset was detected internally. Most likely
+an operator needed a target but that target had not been allocated
+for whatever reason.
=item panic: pad_swipe curpad, %p!=%p
command-line switch. (This output goes to STDOUT unless you've
redirected it with select().)
-=item (perhaps you forgot to load "%s"?)
-
-(F) This is an educated guess made in conjunction with the message
-"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
utility to report; in regex; marked by S<<-- HERE> in m/%s/
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,
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 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 pid %x not a child
(W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
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 <> at require-statement 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,
instead, which does return. To suppress this warning, put the exec() in
a block by itself.
+=item "state" subroutine %s can't be in a package
+
+(F) Lexically scoped subroutines aren't in a package, so it doesn't make
+sense to try to declare one with a package qualifier on the front.
+
=item "state %s" used in sort comparison
(W syntax) The package variables $a and $b are used for sort comparisons.
The <-- HERE shows whereabouts in the regular expression the problem was
discovered. See L<perlre>.
+=item Switch (?(condition)... not terminated in regex; marked by
+S<<-- HERE> in m/%s/
+
+(F) You omitted to close a (?(condition)...) block somewhere
+in the pattern. Add a closing parenthesis in the appropriate
+position. See L<perlre>.
+
=item switching effective %s is not implemented
(F) While under the C<use filetest> pragma, we cannot switch the real
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,
+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 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. 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';>.
+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 "serious" 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.
+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
=item Using just the first character returned by \N{} in character class in
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
-a regular expression pattern bracketed character class.
+(W regexp) Named Unicode character escapes C<(\N{...})> may return
+a multi-character sequence. Even though a character class is
+supposed to match just one character of input, perl will match
+the whole thing correctly, except when the class is inverted
+(C<[^...]>), or the escape is the beginning or final end point of
+a range. For these, what should happen isn't clear at all. In
+these circumstances, Perl discards all but the first character
+of the returned sequence, which is not likely what you want.
=item Using !~ with %s doesn't make sense
=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
+(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>
https://perl5.git.perl.org / perl5.git / blobdiff