3 perldiag - various Perl diagnostics
7 These messages are classified as follows (listed in increasing order of
10 (W) A warning (optional).
11 (D) A deprecation (enabled by default).
12 (S) A severe warning (enabled by default).
13 (F) A fatal error (trappable).
14 (P) An internal error you should never see (trappable).
15 (X) A very fatal error (nontrappable).
16 (A) An alien error message (not generated by Perl).
18 The majority of messages from the first three classifications above
19 (W, D & S) can be controlled using the C<warnings> pragma.
21 If a message can be controlled by the C<warnings> pragma, its warning
22 category is included with the classification letter in the description
23 below. E.g. C<(W closed)> means a warning in the C<closed> category.
25 Optional warnings are enabled by using the C<warnings> pragma or the B<-w>
26 and B<-W> switches. Warnings may be captured by setting C<$SIG{__WARN__}>
27 to a reference to a routine that will be called on each warning instead
28 of printing it. See L<perlvar>.
30 Severe warnings are always enabled, unless they are explicitly disabled
31 with the C<warnings> pragma or the B<-X> switch.
33 Trappable errors may be trapped using the eval operator. See
34 L<perlfunc/eval>. In almost all cases, warnings may be selectively
35 disabled or promoted to fatal errors using the C<warnings> pragma.
38 The messages are in alphabetical order, without regard to upper or
39 lower-case. Some of these messages are generic. Spots that vary are
40 denoted with a %s or other printf-style escape. These escapes are
41 ignored by the alphabetical order, as are all characters other than
42 letters. To look up your message, just ignore anything that is not a
47 =item accept() on closed socket %s
49 (W closed) You tried to do an accept on a closed socket. Did you forget
50 to check the return value of your socket() call? See
53 =item Aliasing via reference is experimental
55 (S experimental::refaliasing) This warning is emitted if you use
56 a reference constructor on the left-hand side of an assignment to
57 alias one variable to another. Simply suppress the warning if you
58 want to use the feature, but know that in doing so you are taking
59 the risk of using an experimental feature which may change or be
60 removed in a future Perl version:
62 no warnings "experimental::refaliasing";
63 use feature "refaliasing";
66 =item Allocation too large: %x
68 (X) You can't allocate more than 64K on an MS-DOS machine.
70 =item '%c' allowed only after types %s in %s
72 (F) The modifiers '!', '<' and '>' are allowed in pack() or unpack() only
73 after certain types. See L<perlfunc/pack>.
75 =item alpha->numify() is lossy
77 (W numeric) An alpha version can not be numified without losing
80 =item Ambiguous call resolved as CORE::%s(), qualify as such or use &
82 (W ambiguous) A subroutine you have declared has the same name as a Perl
83 keyword, and you have used the name without qualification for calling
84 one or the other. Perl decided to call the builtin because the
85 subroutine is not imported.
87 To force interpretation as a subroutine call, either put an ampersand
88 before the subroutine name, or qualify the name with its package.
89 Alternatively, you can import the subroutine (or pretend that it's
90 imported with the C<use subs> pragma).
92 To silently interpret it as the Perl operator, use the C<CORE::> prefix
93 on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
94 to be an object method (see L<perlsub/"Subroutine Attributes"> or
97 =item Ambiguous range in transliteration operator
99 (F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
100 all. To include a C<-> character in a transliteration, put it either
101 first or last. (In the past, C<tr/a-z-0//> was synonymous with
102 C<tr/a-y//>, which was probably not what you would have expected.)
104 =item Ambiguous use of %s resolved as %s
106 (S ambiguous) You said something that may not be interpreted the way
107 you thought. Normally it's pretty easy to disambiguate it by supplying
108 a missing quote, operator, parenthesis pair or declaration.
110 =item Ambiguous use of -%s resolved as -&%s()
112 (S ambiguous) You wrote something like C<-foo>, which might be the
113 string C<"-foo">, or a call to the function C<foo>, negated. If you meant
114 the string, just write C<"-foo">. If you meant the function call,
117 =item Ambiguous use of %c resolved as operator %c
119 (S ambiguous) C<%>, C<&>, and C<*> are both infix operators (modulus,
120 bitwise and, and multiplication) I<and> initial special characters
121 (denoting hashes, subroutines and typeglobs), and you said something
122 like C<*foo * foo> that might be interpreted as either of them. We
123 assumed you meant the infix operator, but please try to make it more
124 clear -- in the example given, you might write C<*foo * foo()> if you
125 really meant to multiply a glob by the result of calling a function.
127 =item Ambiguous use of %c{%s} resolved to %c%s
129 (W ambiguous) You wrote something like C<@{foo}>, which might be
130 asking for the variable C<@foo>, or it might be calling a function
131 named foo, and dereferencing it as an array reference. If you wanted
132 the variable, you can just write C<@foo>. If you wanted to call the
133 function, write C<@{foo()}> ... or you could just not have a variable
134 and a function with the same name, and save yourself a lot of trouble.
136 =item Ambiguous use of %c{%s[...]} resolved to %c%s[...]
138 =item Ambiguous use of %c{%s{...}} resolved to %c%s{...}
140 (W ambiguous) You wrote something like C<${foo[2]}> (where foo represents
141 the name of a Perl keyword), which might be looking for element number
142 2 of the array named C<@foo>, in which case please write C<$foo[2]>, or you
143 might have meant to pass an anonymous arrayref to the function named
144 foo, and then do a scalar deref on the value it returns. If you meant
145 that, write C<${foo([2])}>.
147 In regular expressions, the C<${foo[2]}> syntax is sometimes necessary
148 to disambiguate between array subscripts and character classes.
149 C</$length[2345]/>, for instance, will be interpreted as C<$length> followed
150 by the character class C<[2345]>. If an array subscript is what you
151 want, you can avoid the warning by changing C</${length[2345]}/> to the
152 unsightly C</${\$length[2345]}/>, by renaming your array to something
153 that does not coincide with a built-in keyword, or by simply turning
154 off warnings with C<no warnings 'ambiguous';>.
156 =item '|' and '<' may not both be specified on command line
158 (F) An error peculiar to VMS. Perl does its own command line
159 redirection, and found that STDIN was a pipe, and that you also tried to
160 redirect STDIN using '<'. Only one STDIN stream to a customer, please.
162 =item '|' and '>' may not both be specified on command line
164 (F) An error peculiar to VMS. Perl does its own command line
165 redirection, and thinks you tried to redirect stdout both to a file and
166 into a pipe to another command. You need to choose one or the other,
167 though nothing's stopping you from piping into a program or Perl script
168 which 'splits' output into two streams, such as
170 open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
177 =item Applying %s to %s will act on scalar(%s)
179 (W misc) The pattern match (C<//>), substitution (C<s///>), and
180 transliteration (C<tr///>) operators work on scalar values. If you apply
181 one of them to an array or a hash, it will convert the array or hash to
182 a scalar value (the length of an array, or the population info of a
183 hash) and then work on that scalar value. This is probably not what
184 you meant to do. See L<perlfunc/grep> and L<perlfunc/map> for
187 =item Arg too short for msgsnd
189 (F) msgsnd() requires a string at least as long as sizeof(long).
191 =item Argument "%s" isn't numeric%s
193 (W numeric) The indicated string was fed as an argument to an operator
194 that expected a numeric value instead. If you're fortunate the message
195 will identify which operator was so unfortunate.
197 Note that for the C<Inf> and C<NaN> (infinity and not-a-number) the
198 definition of "numeric" is somewhat unusual: the strings themselves
199 (like "Inf") are considered numeric, and anything following them is
200 considered non-numeric.
202 =item Argument list not closed for PerlIO layer "%s"
204 (W layer) When pushing a layer with arguments onto the Perl I/O
205 system you forgot the ) that closes the argument list. (Layers
206 take care of transforming data between external and internal
207 representations.) Perl stopped parsing the layer list at this
208 point and did not attempt to push this layer. If your program
209 didn't explicitly request the failing operation, it may be the
210 result of the value of the environment variable PERLIO.
212 =item Argument "%s" treated as 0 in increment (++)
214 (W numeric) The indicated string was fed as an argument to the C<++>
215 operator which expects either a number or a string matching
216 C</^[a-zA-Z]*[0-9]*\z/>. See L<perlop/Auto-increment and
217 Auto-decrement> for details.
219 =item Array passed to stat will be coerced to a scalar%s
221 (W syntax) You called stat() on an array, but the array will be
222 coerced to a scalar - the number of elements in the array.
224 =item A signature parameter must start with '$', '@' or '%'
226 (F) Each subroutine signature parameter declaration must start with a valid
229 sub foo ($a, $, $b = 1, @c) {}
231 =item A slurpy parameter may not have a default value
233 (F) Only scalar subroutine signature parameters may have a default value;
236 sub foo ($a = 1) {} # legal
237 sub foo (@a = (1)) {} # invalid
238 sub foo (%a = (a => b)) {} # invalid
240 =item assertion botched: %s
242 (X) The malloc package that comes with Perl had an internal failure.
244 =item Assertion %s failed: file "%s", line %d
246 (X) A general assertion failed. The file in question must be examined.
248 =item Assigned value is not a reference
250 (F) You tried to assign something that was not a reference to an lvalue
251 reference (e.g., C<\$x = $y>). If you meant to make $x an alias to $y, use
254 =item Assigned value is not %s reference
256 (F) You tried to assign a reference to a reference constructor, but the
257 two references were not of the same type. You cannot alias a scalar to
258 an array, or an array to a hash; the two types must match.
263 \$x = $y; # error; did you mean \$y?
265 =item Assigning non-zero to $[ is no longer possible
267 (F) When the "array_base" feature is disabled (e.g., under C<use v5.16;>)
268 the special variable C<$[>, which is deprecated, is now a fixed zero value.
270 =item Assignment to both a list and a scalar
272 (F) If you assign to a conditional operator, the 2nd and 3rd arguments
273 must either both be scalars or both be lists. Otherwise Perl won't
274 know which context to supply to the right side.
276 =item Assuming NOT a POSIX class since %s in regex; marked by S<<-- HERE> in m/%s/
278 (W regexp) You had something like these:
283 They look like they might have been meant to be the POSIX classes
284 C<[:alnum:]> or C<[:digit:]>. If so, they should be written:
289 Since these aren't legal POSIX class specifications, but are legal
290 bracketed character classes, Perl treats them as the latter. In the
291 first example, it matches the characters C<":">, C<"[">, C<"a">, C<"l">,
292 C<"m">, C<"n">, and C<"u">.
294 If these weren't meant to be POSIX classes, this warning message is
295 spurious, and can be suppressed by reordering things, such as
303 =item <> at require-statement should be quotes
305 (F) You wrote C<< require <file> >> when you should have written
308 =item Attempt to access disallowed key '%s' in a restricted hash
310 (F) The failing code has attempted to get or set a key which is not in
311 the current set of allowed keys of a restricted hash.
313 =item Attempt to bless into a freed package
315 (F) You wrote C<bless $foo> with one argument after somehow causing
316 the current package to be freed. Perl cannot figure out what to
317 do, so it throws up in hands in despair.
319 =item Attempt to bless into a reference
321 (F) The CLASSNAME argument to the bless() operator is expected to be
322 the name of the package to bless the resulting object into. You've
323 supplied instead a reference to something: perhaps you wrote
329 bless $self, ref($proto) || $proto;
331 If you actually want to bless into the stringified version
332 of the reference supplied, you need to stringify it yourself, for
335 bless $self, "$proto";
337 =item Attempt to clear deleted array
339 (S debugging) An array was assigned to when it was being freed.
340 Freed values are not supposed to be visible to Perl code. This
341 can also happen if XS code calls C<av_clear> from a custom magic
342 callback on the array.
344 =item Attempt to delete disallowed key '%s' from a restricted hash
346 (F) The failing code attempted to delete from a restricted hash a key
347 which is not in its key set.
349 =item Attempt to delete readonly key '%s' from a restricted hash
351 (F) The failing code attempted to delete a key whose value has been
352 declared readonly from a restricted hash.
354 =item Attempt to free non-arena SV: 0x%x
356 (S internal) All SV objects are supposed to be allocated from arenas
357 that will be garbage collected on exit. An SV was discovered to be
358 outside any of those arenas.
360 =item Attempt to free nonexistent shared string '%s'%s
362 (S internal) Perl maintains a reference-counted internal table of
363 strings to optimize the storage and access of hash keys and other
364 strings. This indicates someone tried to decrement the reference count
365 of a string that can no longer be found in the table.
367 =item Attempt to free temp prematurely: SV 0x%x
369 (S debugging) Mortalized values are supposed to be freed by the
370 free_tmps() routine. This indicates that something else is freeing the
371 SV before the free_tmps() routine gets a chance, which means that the
372 free_tmps() routine will be freeing an unreferenced scalar when it does
375 =item Attempt to free unreferenced glob pointers
377 (S internal) The reference counts got screwed up on symbol aliases.
379 =item Attempt to free unreferenced scalar: SV 0x%x
381 (S internal) Perl went to decrement the reference count of a scalar to
382 see if it would go to 0, and discovered that it had already gone to 0
383 earlier, and should have been freed, and in fact, probably was freed.
384 This could indicate that SvREFCNT_dec() was called too many times, or
385 that SvREFCNT_inc() was called too few times, or that the SV was
386 mortalized when it shouldn't have been, or that memory has been
389 =item Attempt to pack pointer to temporary value
391 (W pack) You tried to pass a temporary value (like the result of a
392 function, or a computed expression) to the "p" pack() template. This
393 means the result contains a pointer to a location that could become
394 invalid anytime, even before the end of the current statement. Use
395 literals or global values as arguments to the "p" pack() template to
398 =item Attempt to reload %s aborted.
400 (F) You tried to load a file with C<use> or C<require> that failed to
401 compile once already. Perl will not try to compile this file again
402 unless you delete its entry from %INC. See L<perlfunc/require> and
405 =item Attempt to set length of freed array
407 (W misc) You tried to set the length of an array which has
408 been freed. You can do this by storing a reference to the
409 scalar representing the last index of an array and later
410 assigning through that reference. For example
412 $r = do {my @a; \$#a};
415 =item Attempt to use reference as lvalue in substr
417 (W substr) You supplied a reference as the first argument to substr()
418 used as an lvalue, which is pretty strange. Perhaps you forgot to
419 dereference it first. See L<perlfunc/substr>.
421 =item Attribute prototype(%s) discards earlier prototype attribute in same sub
423 (W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
424 example. Since each sub can only have one prototype, the earlier
425 declaration(s) are discarded while the last one is applied.
427 =item av_reify called on tied array
429 (S debugging) This indicates that something went wrong and Perl got I<very>
430 confused about C<@_> or C<@DB::args> being tied.
432 =item Bad arg length for %s, is %u, should be %d
434 (F) You passed a buffer of the wrong size to one of msgctl(), semctl()
435 or shmctl(). In C parlance, the correct sizes are, respectively,
436 S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
437 S<sizeof(struct shmid_ds *)>.
439 =item Bad evalled substitution pattern
441 (F) You've used the C</e> switch to evaluate the replacement for a
442 substitution, but perl found a syntax error in the code to evaluate,
443 most likely an unexpected right brace '}'.
445 =item Bad filehandle: %s
447 (F) A symbol was passed to something wanting a filehandle, but the
448 symbol has no filehandle associated with it. Perhaps you didn't do an
449 open(), or did it in another package.
451 =item Bad free() ignored
453 (S malloc) An internal routine called free() on something that had never
454 been malloc()ed in the first place. Mandatory, but can be disabled by
455 setting environment variable C<PERL_BADFREE> to 0.
457 This message can be seen quite often with DB_File on systems with "hard"
458 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
459 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
463 (P) One of the internal hash routines was passed a null HV pointer.
465 =item Badly placed ()'s
467 (A) You've accidentally run your script through B<csh> instead
468 of Perl. Check the #! line, or manually feed your script into
471 =item Bad name after %s
473 (F) You started to name a symbol by using a package prefix, and then
474 didn't finish the symbol. In particular, you can't interpolate outside
483 $sym = "mypack::$var";
485 =item Bad plugin affecting keyword '%s'
487 (F) An extension using the keyword plugin mechanism violated the
490 =item Bad realloc() ignored
492 (S malloc) An internal routine called realloc() on something that
493 had never been malloc()ed in the first place. Mandatory, but can
494 be disabled by setting the environment variable C<PERL_BADFREE> to 1.
496 =item Bad symbol for array
498 (P) An internal request asked to add an array entry to something that
499 wasn't a symbol table entry.
501 =item Bad symbol for dirhandle
503 (P) An internal request asked to add a dirhandle entry to something
504 that wasn't a symbol table entry.
506 =item Bad symbol for filehandle
508 (P) An internal request asked to add a filehandle entry to something
509 that wasn't a symbol table entry.
511 =item Bad symbol for hash
513 (P) An internal request asked to add a hash entry to something that
514 wasn't a symbol table entry.
516 =item Bad symbol for scalar
518 (P) An internal request asked to add a scalar entry to something that
519 wasn't a symbol table entry.
521 =item Bareword found in conditional
523 (W bareword) The compiler found a bareword where it expected a
524 conditional, which often indicates that an || or && was parsed as part
525 of the last argument of the previous construct, for example:
529 It may also indicate a misspelled constant that has been interpreted as
532 use constant TYPO => 1;
533 if (TYOP) { print "foo" }
535 The C<strict> pragma is useful in avoiding such errors.
537 =item Bareword in require contains "%s"
539 =item Bareword in require maps to disallowed filename "%s"
541 =item Bareword in require maps to empty filename
543 (F) The bareword form of require has been invoked with a filename which could
544 not have been generated by a valid bareword permitted by the parser. You
545 shouldn't be able to get this error from Perl code, but XS code may throw it
546 if it passes an invalid module name to C<Perl_load_module>.
548 =item Bareword in require must not start with a double-colon: "%s"
550 (F) In C<require Bare::Word>, the bareword is not allowed to start with a
551 double-colon. Write C<require ::Foo::Bar> as C<require Foo::Bar> instead.
553 =item Bareword "%s" not allowed while "strict subs" in use
555 (F) With "strict subs" in use, a bareword is only allowed as a
556 subroutine identifier, in curly brackets or to the left of the "=>"
557 symbol. Perhaps you need to predeclare a subroutine?
559 =item Bareword "%s" refers to nonexistent package
561 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
562 compiler saw no other uses of that namespace before that point. Perhaps
563 you need to predeclare a package?
565 =item BEGIN failed--compilation aborted
567 (F) An untrapped exception was raised while executing a BEGIN
568 subroutine. Compilation stops immediately and the interpreter is
571 =item BEGIN not safe after errors--compilation aborted
573 (F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
574 implies a C<BEGIN {}>) after one or more compilation errors had already
575 occurred. Since the intended environment for the C<BEGIN {}> could not
576 be guaranteed (due to the errors), and since subsequent code likely
577 depends on its correct operation, Perl just gave up.
579 =item \%d better written as $%d
581 (W syntax) Outside of patterns, backreferences live on as variables.
582 The use of backslashes is grandfathered on the right-hand side of a
583 substitution, but stylistically it's better to use the variable form
584 because other Perl programmers will expect it, and it works better if
585 there are more than 9 backreferences.
587 =item Binary number > 0b11111111111111111111111111111111 non-portable
589 (W portable) The binary number you specified is larger than 2**32-1
590 (4294967295) and therefore non-portable between systems. See
591 L<perlport> for more on portability concerns.
593 =item bind() on closed socket %s
595 (W closed) You tried to do a bind on a closed socket. Did you forget to
596 check the return value of your socket() call? See L<perlfunc/bind>.
598 =item binmode() on closed filehandle %s
600 (W unopened) You tried binmode() on a filehandle that was never opened.
601 Check your control flow and number of arguments.
603 =item Bit vector size > 32 non-portable
605 (W portable) Using bit vector sizes larger than 32 is non-portable.
607 =item Bizarre copy of %s
609 (P) Perl detected an attempt to copy an internal value that is not
612 =item Bizarre SvTYPE [%d]
614 (P) When starting a new thread or returning values from a thread, Perl
615 encountered an invalid data type.
617 =item Both or neither range ends should be Unicode in regex; marked by
620 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
622 In a bracketed character class in a regular expression pattern, you
623 had a range which has exactly one end of it specified using C<\N{}>, and
624 the other end is specified using a non-portable mechanism. Perl treats
625 the range as a Unicode range, that is, all the characters in it are
626 considered to be the Unicode characters, and which may be different code
627 points on some platforms Perl runs on. For example, C<[\N{U+06}-\x08]>
628 is treated as if you had instead said C<[\N{U+06}-\N{U+08}]>, that is it
629 matches the characters whose code points in Unicode are 6, 7, and 8.
630 But that C<\x08> might indicate that you meant something different, so
631 the warning gets raised.
633 =item Buffer overflow in prime_env_iter: %s
635 (W internal) A warning peculiar to VMS. While Perl was preparing to
636 iterate over %ENV, it encountered a logical name or symbol definition
637 which was too long, so it was truncated to the string shown.
639 =item Callback called exit
641 (F) A subroutine invoked from an external package via call_sv()
642 exited by calling exit.
644 =item %s() called too early to check prototype
646 (W prototype) You've called a function that has a prototype before the
647 parser saw a definition or declaration for it, and Perl could not check
648 that the call conforms to the prototype. You need to either add an
649 early prototype declaration for the subroutine in question, or move the
650 subroutine definition ahead of the call to get proper prototype
651 checking. Alternatively, if you are certain that you're calling the
652 function correctly, you may put an ampersand before the name to avoid
653 the warning. See L<perlsub>.
657 (F) You passed an invalid number (like an infinity or not-a-number) to C<chr>.
659 =item Cannot compress %f in pack
661 (F) You tried compressing an infinity or not-a-number as an unsigned
662 integer with BER, which makes no sense.
664 =item Cannot compress integer in pack
666 (F) An argument to pack("w",...) was too large to compress.
667 The BER compressed integer format can only be used with positive
668 integers, and you attempted to compress a very large number (> 1e308).
669 See L<perlfunc/pack>.
671 =item Cannot compress negative numbers in pack
673 (F) An argument to pack("w",...) was negative. The BER compressed integer
674 format can only be used with positive integers. See L<perlfunc/pack>.
676 =item Cannot convert a reference to %s to typeglob
678 (F) You manipulated Perl's symbol table directly, stored a reference
679 in it, then tried to access that symbol via conventional Perl syntax.
680 The access triggers Perl to autovivify that typeglob, but it there is
681 no legal conversion from that type of reference to a typeglob.
683 =item Cannot copy to %s
685 (P) Perl detected an attempt to copy a value to an internal type that cannot
686 be directly assigned to.
688 =item Cannot find encoding "%s"
690 (S io) You tried to apply an encoding that did not exist to a filehandle,
691 either with open() or binmode().
693 =item Cannot pack %f with '%c'
695 (F) You tried converting an infinity or not-a-number to an integer,
696 which makes no sense.
698 =item Cannot printf %f with '%c'
700 (F) You tried printing an infinity or not-a-number as a character (%c),
701 which makes no sense. Maybe you meant '%s', or just stringifying it?
703 =item Cannot set tied @DB::args
705 (F) C<caller> tried to set C<@DB::args>, but found it tied. Tying C<@DB::args>
706 is not supported. (Before this error was added, it used to crash.)
708 =item Cannot tie unreifiable array
710 (P) You somehow managed to call C<tie> on an array that does not
711 keep a reference count on its arguments and cannot be made to
712 do so. Such arrays are not even supposed to be accessible to
713 Perl code, but are only used internally.
715 =item Cannot yet reorder sv_catpvfn() arguments from va_list
717 (F) Some XS code tried to use C<sv_catpvfn()> or a related function with a
718 format string that specifies explicit indexes for some of the elements, and
719 using a C-style variable-argument list (a C<va_list>). This is not currently
720 supported. XS authors wanting to do this must instead construct a C array
721 of C<SV*> scalars containing the arguments.
723 =item Can only compress unsigned integers in pack
725 (F) An argument to pack("w",...) was not an integer. The BER compressed
726 integer format can only be used with positive integers, and you attempted
727 to compress something else. See L<perlfunc/pack>.
729 =item Can't bless non-reference value
731 (F) Only hard references may be blessed. This is how Perl "enforces"
732 encapsulation of objects. See L<perlobj>.
734 =item Can't "break" in a loop topicalizer
736 (F) You called C<break>, but you're in a C<foreach> block rather than
737 a C<given> block. You probably meant to use C<next> or C<last>.
739 =item Can't "break" outside a given block
741 (F) You called C<break>, but you're not inside a C<given> block.
743 =item Can't call method "%s" on an undefined value
745 (F) You used the syntax of a method call, but the slot filled by the
746 object reference or package name contains an undefined value. Something
747 like this will reproduce the error:
750 process $BADREF 1,2,3;
751 $BADREF->process(1,2,3);
753 =item Can't call method "%s" on unblessed reference
755 (F) A method call must know in what package it's supposed to run. It
756 ordinarily finds this out from the object reference you supply, but you
757 didn't supply an object reference in this case. A reference isn't an
758 object reference until it has been blessed. See L<perlobj>.
760 =item Can't call method "%s" without a package or object reference
762 (F) You used the syntax of a method call, but the slot filled by the
763 object reference or package name contains an expression that returns a
764 defined value which is neither an object reference nor a package name.
765 Something like this will reproduce the error:
768 process $BADREF 1,2,3;
769 $BADREF->process(1,2,3);
771 =item Can't call mro_isa_changed_in() on anonymous symbol table
773 (P) Perl got confused as to whether a hash was a plain hash or a
774 symbol table hash when trying to update @ISA caches.
776 =item Can't call mro_method_changed_in() on anonymous symbol table
778 (F) An XS module tried to call C<mro_method_changed_in> on a hash that was
779 not attached to the symbol table.
781 =item Can't chdir to %s
783 (F) You called C<perl -x/foo/bar>, but F</foo/bar> is not a directory
784 that you can chdir to, possibly because it doesn't exist.
786 =item Can't check filesystem of script "%s" for nosuid
788 (P) For some reason you can't check the filesystem of the script for
791 =item Can't coerce %s to %s in %s
793 (F) Certain types of SVs, in particular real symbol table entries
794 (typeglobs), can't be forced to stop being what they are. So you can't
804 but then $foo no longer contains a glob.
806 =item Can't "continue" outside a when block
808 (F) You called C<continue>, but you're not inside a C<when>
811 =item Can't create pipe mailbox
813 (P) An error peculiar to VMS. The process is suffering from exhausted
814 quotas or other plumbing problems.
816 =item Can't declare %s in "%s"
818 (F) Only scalar, array, and hash variables may be declared as "my", "our" or
819 "state" variables. They must have ordinary identifiers as names.
821 =item Can't "default" outside a topicalizer
823 (F) You have used a C<default> block that is neither inside a
824 C<foreach> loop nor a C<given> block. (Note that this error is
825 issued on exit from the C<default> block, so you won't get the
826 error if you use an explicit C<continue>.)
828 =item Can't determine class of operator %s, assuming BASEOP
830 (S) This warning indicates something wrong in the internals of perl.
831 Perl was trying to find the class (e.g. LISTOP) of a particular OP,
832 and was unable to do so. This is likely to be due to a bug in the perl
833 internals, or due to a bug in XS code which manipulates perl optrees.
835 =item Can't do inplace edit: %s is not a regular file
837 (S inplace) You tried to use the B<-i> switch on a special file, such as
838 a file in /dev, a FIFO or an uneditable directory. The file was ignored.
840 =item Can't do inplace edit on %s: %s
842 (S inplace) The creation of the new file failed for the indicated
845 =item Can't do inplace edit without backup
847 (F) You're on a system such as MS-DOS that gets confused if you try
848 reading from a deleted (but still opened) file. You have to say
849 C<-i.bak>, or some such.
851 =item Can't do inplace edit: %s would not be unique
853 (S inplace) Your filesystem does not support filenames longer than 14
854 characters and Perl was unable to create a unique filename during
855 inplace editing with the B<-i> switch. The file was ignored.
857 =item Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".
859 (W locale) You are 1) running under "C<use locale>"; 2) the current
860 locale is not a UTF-8 one; 3) you tried to do the designated case-change
861 operation on the specified Unicode character; and 4) the result of this
862 operation would mix Unicode and locale rules, which likely conflict.
863 Mixing of different rule types is forbidden, so the operation was not
864 done; instead the result is the indicated value, which is the best
865 available that uses entirely Unicode rules. That turns out to almost
866 always be the original character, unchanged.
868 It is generally a bad idea to mix non-UTF-8 locales and Unicode, and
869 this issue is one of the reasons why. This warning is raised when
870 Unicode rules would normally cause the result of this operation to
871 contain a character that is in the range specified by the locale,
872 0..255, and hence is subject to the locale's rules, not Unicode's.
874 If you are using locale purely for its characteristics related to things
875 like its numeric and time formatting (and not C<LC_CTYPE>), consider
876 using a restricted form of the locale pragma (see L<perllocale/The "use
877 locale" pragma>) like "S<C<use locale ':not_characters'>>".
879 Note that failed case-changing operations done as a result of
880 case-insensitive C</i> regular expression matching will show up in this
881 warning as having the C<fc> operation (as that is what the regular
882 expression engine calls behind the scenes.)
884 =item Can't do waitpid with flags
886 (F) This machine doesn't have either waitpid() or wait4(), so only
887 waitpid() without flags is emulated.
889 =item Can't emulate -%s on #! line
891 (F) The #! line specifies a switch that doesn't make sense at this
892 point. For example, it'd be kind of silly to put a B<-x> on the #!
895 =item Can't %s %s-endian %ss on this platform
897 (F) Your platform's byte-order is neither big-endian nor little-endian,
898 or it has a very strange pointer size. Packing and unpacking big- or
899 little-endian floating point values and pointers may not be possible.
900 See L<perlfunc/pack>.
902 =item Can't exec "%s": %s
904 (W exec) A system(), exec(), or piped open call could not execute the
905 named program for the indicated reason. Typical reasons include: the
906 permissions were wrong on the file, the file wasn't found in
907 C<$ENV{PATH}>, the executable in question was compiled for another
908 architecture, or the #! line in a script points to an interpreter that
909 can't be run for similar reasons. (Or maybe your system doesn't support
914 (F) Perl was trying to execute the indicated program for you because
915 that's what the #! line said. If that's not what you wanted, you may
916 need to mention "perl" on the #! line somewhere.
918 =item Can't execute %s
920 (F) You used the B<-S> switch, but the copies of the script to execute
921 found in the PATH did not have correct permissions.
923 =item Can't find an opnumber for "%s"
925 (F) A string of a form C<CORE::word> was given to prototype(), but there
926 is no builtin with the name C<word>.
928 =item Can't find label %s
930 (F) You said to goto a label that isn't mentioned anywhere that it's
931 possible for us to go to. See L<perlfunc/goto>.
933 =item Can't find %s on PATH
935 (F) You used the B<-S> switch, but the script to execute could not be
938 =item Can't find %s on PATH, '.' not in PATH
940 (F) You used the B<-S> switch, but the script to execute could not be
941 found in the PATH, or at least not with the correct permissions. The
942 script exists in the current directory, but PATH prohibits running it.
944 =item Can't find string terminator %s anywhere before EOF
946 (F) Perl strings can stretch over multiple lines. This message means
947 that the closing delimiter was omitted. Because bracketed quotes count
948 nesting levels, the following is missing its final parenthesis:
950 print q(The character '(' starts a side comment.);
952 If you're getting this error from a here-document, you may have
953 included unseen whitespace before or after your closing tag or there
954 may not be a linebreak after it. A good programmer's editor will have
955 a way to help you find these characters (or lack of characters). See
956 L<perlop> for the full details on here-documents.
958 =item Can't find Unicode property definition "%s"
960 =item Can't find Unicode property definition "%s" in regex; marked by <-- HERE in m/%s/
962 (F) The named property which you specified via C<\p> or C<\P> is not one
963 known to Perl. Perhaps you misspelled the name? See
964 L<perluniprops/Properties accessible through \p{} and \P{}>
965 for a complete list of available official
966 properties. If it is a
967 L<user-defined property|perlunicode/User-Defined Character Properties>
968 it must have been defined by the time the regular expression is
971 If you didn't mean to use a Unicode property, escape the C<\p>, either
972 by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, or
977 (F) A fatal error occurred while trying to fork while opening a
980 =item Can't fork, trying again in 5 seconds
982 (W pipe) A fork in a piped open failed with EAGAIN and will be retried
985 =item Can't get filespec - stale stat buffer?
987 (S) A warning peculiar to VMS. This arises because of the difference
988 between access checks under VMS and under the Unix model Perl assumes.
989 Under VMS, access checks are done by filename, rather than by bits in
990 the stat buffer, so that ACLs and other protections can be taken into
991 account. Unfortunately, Perl assumes that the stat buffer contains all
992 the necessary information, and passes it, instead of the filespec, to
993 the access-checking routine. It will try to retrieve the filespec using
994 the device name and FID present in the stat buffer, but this works only
995 if you haven't made a subsequent call to the CRTL stat() routine,
996 because the device name is overwritten with each call. If this warning
997 appears, the name lookup failed, and the access-checking routine gave up
998 and returned FALSE, just to be conservative. (Note: The access-checking
999 routine knows about the Perl C<stat> operator and file tests, so you
1000 shouldn't ever see this warning in response to a Perl command; it arises
1001 only if some internal code takes stat buffers lightly.)
1003 =item Can't get pipe mailbox device name
1005 (P) An error peculiar to VMS. After creating a mailbox to act as a
1006 pipe, Perl can't retrieve its name for later use.
1008 =item Can't get SYSGEN parameter value for MAXBUF
1010 (P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
1011 mailbox buffers to be, and didn't get an answer.
1013 =item Can't "goto" into the middle of a foreach loop
1015 (F) A "goto" statement was executed to jump into the middle of a foreach
1016 loop. You can't get there from here. See L<perlfunc/goto>.
1018 =item Can't "goto" out of a pseudo block
1020 (F) A "goto" statement was executed to jump out of what might look like
1021 a block, except that it isn't a proper block. This usually occurs if
1022 you tried to jump out of a sort() block or subroutine, which is a no-no.
1023 See L<perlfunc/goto>.
1025 =item Can't goto subroutine from an eval-%s
1027 (F) The "goto subroutine" call can't be used to jump out of an eval
1030 =item Can't goto subroutine from a sort sub (or similar callback)
1032 (F) The "goto subroutine" call can't be used to jump out of the
1033 comparison sub for a sort(), or from a similar callback (such
1034 as the reduce() function in List::Util).
1036 =item Can't goto subroutine outside a subroutine
1038 (F) The deeply magical "goto subroutine" call can only replace one
1039 subroutine call for another. It can't manufacture one out of whole
1040 cloth. In general you should be calling it out of only an AUTOLOAD
1041 routine anyway. See L<perlfunc/goto>.
1043 =item Can't ignore signal CHLD, forcing to default
1045 (W signal) Perl has detected that it is being run with the SIGCHLD
1046 signal (sometimes known as SIGCLD) disabled. Since disabling this
1047 signal will interfere with proper determination of exit status of child
1048 processes, Perl has reset the signal to its default value. This
1049 situation typically indicates that the parent program under which Perl
1050 may be running (e.g. cron) is being very careless.
1052 =item Can't kill a non-numeric process ID
1054 (F) Process identifiers must be (signed) integers. It is a fatal error to
1055 attempt to kill() an undefined, empty-string or otherwise non-numeric
1058 =item Can't "last" outside a loop block
1060 (F) A "last" statement was executed to break out of the current block,
1061 except that there's this itty bitty problem called there isn't a current
1062 block. Note that an "if" or "else" block doesn't count as a "loopish"
1063 block, as doesn't a block given to sort(), map() or grep(). You can
1064 usually double the curlies to get the same effect though, because the
1065 inner curlies will be considered a block that loops once. See
1068 =item Can't linearize anonymous symbol table
1070 (F) Perl tried to calculate the method resolution order (MRO) of a
1071 package, but failed because the package stash has no name.
1073 =item Can't load '%s' for module %s
1075 (F) The module you tried to load failed to load a dynamic extension.
1076 This may either mean that you upgraded your version of perl to one
1077 that is incompatible with your old dynamic extensions (which is known
1078 to happen between major versions of perl), or (more likely) that your
1079 dynamic extension was built against an older version of the library
1080 that is installed on your system. You may need to rebuild your old
1083 =item Can't localize lexical variable %s
1085 (F) You used local on a variable name that was previously declared as a
1086 lexical variable using "my" or "state". This is not allowed. If you
1087 want to localize a package variable of the same name, qualify it with
1090 =item Can't localize through a reference
1092 (F) You said something like C<local $$ref>, which Perl can't currently
1093 handle, because when it goes to restore the old value of whatever $ref
1094 pointed to after the scope of the local() is finished, it can't be sure
1095 that $ref will still be a reference.
1097 =item Can't locate %s
1099 (F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be found.
1100 Perl looks for the file in all the locations mentioned in @INC, unless
1101 the file name included the full path to the file. Perhaps you need
1102 to set the PERL5LIB or PERL5OPT environment variable to say where the
1103 extra library is, or maybe the script needs to add the library name
1104 to @INC. Or maybe you just misspelled the name of the file. See
1105 L<perlfunc/require> and L<lib>.
1107 =item Can't locate auto/%s.al in @INC
1109 (F) A function (or method) was called in a package which allows
1110 autoload, but there is no function to autoload. Most probable causes
1111 are a misprint in a function/method name or a failure to C<AutoSplit>
1112 the file, say, by doing C<make install>.
1114 =item Can't locate loadable object for module %s in @INC
1116 (F) The module you loaded is trying to load an external library, like
1117 for example, F<foo.so> or F<bar.dll>, but the L<DynaLoader> module was
1118 unable to locate this library. See L<DynaLoader>.
1120 =item Can't locate object method "%s" via package "%s"
1122 (F) You called a method correctly, and it correctly indicated a package
1123 functioning as a class, but that package doesn't define that particular
1124 method, nor does any of its base classes. See L<perlobj>.
1126 =item Can't locate object method "%s" via package "%s" (perhaps you forgot
1129 (F) You called a method on a class that did not exist, and the method
1130 could not be found in UNIVERSAL. This often means that a method
1131 requires a package that has not been loaded.
1133 =item Can't locate package %s for @%s::ISA
1135 (W syntax) The @ISA array contained the name of another package that
1136 doesn't seem to exist.
1138 =item Can't locate PerlIO%s
1140 (F) You tried to use in open() a PerlIO layer that does not exist,
1141 e.g. open(FH, ">:nosuchlayer", "somefile").
1143 =item Can't make list assignment to %ENV on this system
1145 (F) List assignment to %ENV is not supported on some systems, notably
1148 =item Can't make loaded symbols global on this platform while loading %s
1150 (S) A module passed the flag 0x01 to DynaLoader::dl_load_file() to request
1151 that symbols from the stated file are made available globally within the
1152 process, but that functionality is not available on this platform. Whilst
1153 the module likely will still work, this may prevent the perl interpreter
1154 from loading other XS-based extensions which need to link directly to
1155 functions defined in the C or XS code in the stated file.
1157 =item Can't modify %s in %s
1159 (F) You aren't allowed to assign to the item indicated, or otherwise try
1160 to change it, such as with an auto-increment.
1162 =item Can't modify nonexistent substring
1164 (P) The internal routine that does assignment to a substr() was handed
1167 =item Can't modify non-lvalue subroutine call of &%s
1169 (F) Subroutines meant to be used in lvalue context should be declared as
1170 such. See L<perlsub/"Lvalue subroutines">.
1172 =item Can't modify reference to %s in %s assignment
1174 (F) Only a limited number of constructs can be used as the argument to a
1175 reference constructor on the left-hand side of an assignment, and what
1176 you used was not one of them. See L<perlref/Assigning to References>.
1178 =item Can't modify reference to localized parenthesized array in list
1181 (F) Assigning to C<\local(@array)> or C<\(local @array)> is not supported, as
1182 it is not clear exactly what it should do. If you meant to make @array
1183 refer to some other array, use C<\@array = \@other_array>. If you want to
1184 make the elements of @array aliases of the scalars referenced on the
1185 right-hand side, use C<\(@array) = @scalar_refs>.
1187 =item Can't modify reference to parenthesized hash in list assignment
1189 (F) Assigning to C<\(%hash)> is not supported. If you meant to make %hash
1190 refer to some other hash, use C<\%hash = \%other_hash>. If you want to
1191 make the elements of %hash into aliases of the scalars referenced on the
1192 right-hand side, use a hash slice: C<\@hash{@keys} = @those_scalar_refs>.
1194 =item Can't msgrcv to read-only var
1196 (F) The target of a msgrcv must be modifiable to be used as a receive
1199 =item Can't "next" outside a loop block
1201 (F) A "next" statement was executed to reiterate the current block, but
1202 there isn't a current block. Note that an "if" or "else" block doesn't
1203 count as a "loopish" block, as doesn't a block given to sort(), map() or
1204 grep(). You can usually double the curlies to get the same effect
1205 though, because the inner curlies will be considered a block that loops
1206 once. See L<perlfunc/next>.
1208 =item Can't open %s: %s
1210 (S inplace) The implicit opening of a file through use of the C<< <> >>
1211 filehandle, either implicitly under the C<-n> or C<-p> command-line
1212 switches, or explicitly, failed for the indicated reason. Usually
1213 this is because you don't have read permission for a file which
1214 you named on the command line.
1216 (F) You tried to call perl with the B<-e> switch, but F</dev/null> (or
1217 your operating system's equivalent) could not be opened.
1219 =item Can't open a reference
1221 (W io) You tried to open a scalar reference for reading or writing,
1222 using the 3-arg open() syntax:
1226 but your version of perl is compiled without perlio, and this form of
1227 open is not supported.
1229 =item Can't open bidirectional pipe
1231 (W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
1232 You can try any of several modules in the Perl library to do this, such
1233 as IPC::Open2. Alternately, direct the pipe's output to a file using
1234 ">", and then read it in under a different file handle.
1236 =item Can't open error file %s as stderr
1238 (F) An error peculiar to VMS. Perl does its own command line
1239 redirection, and couldn't open the file specified after '2>' or '2>>' on
1240 the command line for writing.
1242 =item Can't open input file %s as stdin
1244 (F) An error peculiar to VMS. Perl does its own command line
1245 redirection, and couldn't open the file specified after '<' on the
1246 command line for reading.
1248 =item Can't open output file %s as stdout
1250 (F) An error peculiar to VMS. Perl does its own command line
1251 redirection, and couldn't open the file specified after '>' or '>>' on
1252 the command line for writing.
1254 =item Can't open output pipe (name: %s)
1256 (P) An error peculiar to VMS. Perl does its own command line
1257 redirection, and couldn't open the pipe into which to send data destined
1260 =item Can't open perl script "%s": %s
1262 (F) The script you specified can't be opened for the indicated reason.
1264 If you're debugging a script that uses #!, and normally relies on the
1265 shell's $PATH search, the -S option causes perl to do that search, so
1266 you don't have to type the path or C<`which $scriptname`>.
1268 =item Can't read CRTL environ
1270 (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
1271 from the CRTL's internal environment array and discovered the array was
1272 missing. You need to figure out where your CRTL misplaced its environ
1273 or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
1276 =item Can't redeclare "%s" in "%s"
1278 (F) A "my", "our" or "state" declaration was found within another declaration,
1279 such as C<my ($x, my($y), $z)> or C<our (my $x)>.
1281 =item Can't "redo" outside a loop block
1283 (F) A "redo" statement was executed to restart the current block, but
1284 there isn't a current block. Note that an "if" or "else" block doesn't
1285 count as a "loopish" block, as doesn't a block given to sort(), map()
1286 or grep(). You can usually double the curlies to get the same effect
1287 though, because the inner curlies will be considered a block that
1288 loops once. See L<perlfunc/redo>.
1290 =item Can't remove %s: %s, skipping file
1292 (S inplace) You requested an inplace edit without creating a backup
1293 file. Perl was unable to remove the original file to replace it with
1294 the modified file. The file was left unmodified.
1296 =item Can't rename %s to %s: %s, skipping file
1298 (S inplace) The rename done by the B<-i> switch failed for some reason,
1299 probably because you don't have write permission to the directory.
1301 =item Can't reopen input pipe (name: %s) in binary mode
1303 (P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
1304 to reopen it to accept binary data. Alas, it failed.
1306 =item Can't represent character for Ox%X on this platform
1308 (F) There is a hard limit to how big a character code point can be due
1309 to the fundamental properties of UTF-8, especially on EBCDIC
1310 platforms. The given code point exceeds that. The only work-around is
1311 to not use such a large code point.
1313 =item Can't reset %ENV on this system
1315 (F) You called C<reset('E')> or similar, which tried to reset
1316 all variables in the current package beginning with "E". In
1317 the main package, that includes %ENV. Resetting %ENV is not
1318 supported on some systems, notably VMS.
1320 =item Can't resolve method "%s" overloading "%s" in package "%s"
1322 (F)(P) Error resolving overloading specified by a method name (as
1323 opposed to a subroutine reference): no such method callable via the
1324 package. If the method name is C<???>, this is an internal error.
1326 =item Can't return %s from lvalue subroutine
1328 (F) Perl detected an attempt to return illegal lvalues (such as
1329 temporary or readonly values) from a subroutine used as an lvalue. This
1332 =item Can't return outside a subroutine
1334 (F) The return statement was executed in mainline code, that is, where
1335 there was no subroutine call to return out of. See L<perlsub>.
1337 =item Can't return %s to lvalue scalar context
1339 (F) You tried to return a complete array or hash from an lvalue
1340 subroutine, but you called the subroutine in a way that made Perl
1341 think you meant to return only one value. You probably meant to
1342 write parentheses around the call to the subroutine, which tell
1343 Perl that the call should be in list context.
1345 =item Can't stat script "%s"
1347 (P) For some reason you can't fstat() the script even though you have it
1348 open already. Bizarre.
1350 =item Can't take log of %g
1352 (F) For ordinary real numbers, you can't take the logarithm of a
1353 negative number or zero. There's a Math::Complex package that comes
1354 standard with Perl, though, if you really want to do that for the
1357 =item Can't take sqrt of %g
1359 (F) For ordinary real numbers, you can't take the square root of a
1360 negative number. There's a Math::Complex package that comes standard
1361 with Perl, though, if you really want to do that.
1363 =item Can't undef active subroutine
1365 (F) You can't undefine a routine that's currently running. You can,
1366 however, redefine it while it's running, and you can even undef the
1367 redefined subroutine while the old routine is running. Go figure.
1369 =item Can't upgrade %s (%d) to %d
1371 (P) The internal sv_upgrade routine adds "members" to an SV, making it
1372 into a more specialized kind of SV. The top several SV types are so
1373 specialized, however, that they cannot be interconverted. This message
1374 indicates that such a conversion was attempted.
1376 =item Can't use '%c' after -mname
1378 (F) You tried to call perl with the B<-m> switch, but you put something
1379 other than "=" after the module name.
1381 =item Can't use a hash as a reference
1383 (F) You tried to use a hash as a reference, as in
1384 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl
1385 <= 5.22.0 used to allow this syntax, but shouldn't
1386 have. This was deprecated in perl 5.6.1.
1388 =item Can't use an array as a reference
1390 (F) You tried to use an array as a reference, as in
1391 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.22.0
1392 used to allow this syntax, but shouldn't have. This
1393 was deprecated in perl 5.6.1.
1395 =item Can't use anonymous symbol table for method lookup
1397 (F) The internal routine that does method lookup was handed a symbol
1398 table that doesn't have a name. Symbol tables can become anonymous
1399 for example by undefining stashes: C<undef %Some::Package::>.
1401 =item Can't use an undefined value as %s reference
1403 (F) A value used as either a hard reference or a symbolic reference must
1404 be a defined value. This helps to delurk some insidious errors.
1406 =item Can't use bareword ("%s") as %s ref while "strict refs" in use
1408 (F) Only hard references are allowed by "strict refs". Symbolic
1409 references are disallowed. See L<perlref>.
1411 =item Can't use %! because Errno.pm is not available
1413 (F) The first time the C<%!> hash is used, perl automatically loads the
1414 Errno.pm module. The Errno module is expected to tie the %! hash to
1415 provide symbolic names for C<$!> errno values.
1417 =item Can't use both '<' and '>' after type '%c' in %s
1419 (F) A type cannot be forced to have both big-endian and little-endian
1420 byte-order at the same time, so this combination of modifiers is not
1421 allowed. See L<perlfunc/pack>.
1423 =item Can't use 'defined(@array)' (Maybe you should just omit the defined()?)
1425 (F) defined() is not useful on arrays because it
1426 checks for an undefined I<scalar> value. If you want to see if the
1427 array is empty, just use C<if (@array) { # not empty }> for example.
1429 =item Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)
1431 (F) C<defined()> is not usually right on hashes.
1433 Although C<defined %hash> is false on a plain not-yet-used hash, it
1434 becomes true in several non-obvious circumstances, including iterators,
1435 weak references, stash names, even remaining true after C<undef %hash>.
1436 These things make C<defined %hash> fairly useless in practice, so it now
1437 generates a fatal error.
1439 If a check for non-empty is what you wanted then just put it in boolean
1440 context (see L<perldata/Scalar values>):
1446 If you had C<defined %Foo::Bar::QUUX> to check whether such a package
1447 variable exists then that's never really been reliable, and isn't
1448 a good way to enquire about the features of a package, or whether
1451 =item Can't use %s for loop variable
1453 (P) The parser got confused when trying to parse a C<foreach> loop.
1455 =item Can't use global %s in "%s"
1457 (F) You tried to declare a magical variable as a lexical variable. This
1458 is not allowed, because the magic can be tied to only one location
1459 (namely the global variable) and it would be incredibly confusing to
1460 have variables in your program that looked like magical variables but
1463 =item Can't use '%c' in a group with different byte-order in %s
1465 (F) You attempted to force a different byte-order on a type
1466 that is already inside a group with a byte-order modifier.
1467 For example you cannot force little-endianness on a type that
1468 is inside a big-endian group.
1470 =item Can't use "my %s" in sort comparison
1472 (F) The global variables $a and $b are reserved for sort comparisons.
1473 You mentioned $a or $b in the same line as the <=> or cmp operator,
1474 and the variable had earlier been declared as a lexical variable.
1475 Either qualify the sort variable with the package name, or rename the
1478 =item Can't use %s ref as %s ref
1480 (F) You've mixed up your reference types. You have to dereference a
1481 reference of the type needed. You can use the ref() function to
1482 test the type of the reference, if need be.
1484 =item Can't use string ("%s") as %s ref while "strict refs" in use
1486 =item Can't use string ("%s"...) as %s ref while "strict refs" in use
1488 (F) You've told Perl to dereference a string, something which
1489 C<use strict> blocks to prevent it happening accidentally. See
1490 L<perlref/"Symbolic references">. This can be triggered by an C<@> or C<$>
1491 in a double-quoted string immediately before interpolating a variable,
1492 for example in C<"user @$twitter_id">, which says to treat the contents
1493 of C<$twitter_id> as an array reference; use a C<\> to have a literal C<@>
1494 symbol followed by the contents of C<$twitter_id>: C<"user \@$twitter_id">.
1496 =item Can't use subscript on %s
1498 (F) The compiler tried to interpret a bracketed expression as a
1499 subscript. But to the left of the brackets was an expression that
1500 didn't look like a hash or array reference, or anything else subscriptable.
1502 =item Can't use \%c to mean $%c in expression
1504 (W syntax) In an ordinary expression, backslash is a unary operator that
1505 creates a reference to its argument. The use of backslash to indicate a
1506 backreference to a matched substring is valid only as part of a regular
1507 expression pattern. Trying to do this in ordinary Perl code produces a
1508 value that prints out looking like SCALAR(0xdecaf). Use the $1 form
1511 =item Can't weaken a nonreference
1513 (F) You attempted to weaken something that was not a reference. Only
1514 references can be weakened.
1516 =item Can't "when" outside a topicalizer
1518 (F) You have used a when() block that is neither inside a C<foreach>
1519 loop nor a C<given> block. (Note that this error is issued on exit
1520 from the C<when> block, so you won't get the error if the match fails,
1521 or if you use an explicit C<continue>.)
1523 =item Can't x= to read-only value
1525 (F) You tried to repeat a constant value (often the undefined value)
1526 with an assignment operator, which implies modifying the value itself.
1527 Perhaps you need to copy the value to a temporary, and repeat that.
1529 =item Character following "\c" must be printable ASCII
1531 (F) In C<\cI<X>>, I<X> must be a printable (non-control) ASCII character.
1533 Note that ASCII characters that don't map to control characters are
1534 discouraged, and will generate the warning (when enabled)
1535 L</""\c%c" is more clearly written simply as "%s"">.
1537 =item Character following \%c must be '{' or a single-character Unicode property name in regex; marked by <-- HERE in m/%s/
1539 (F) (In the above the C<%c> is replaced by either C<p> or C<P>.) You
1540 specified something that isn't a legal Unicode property name. Most
1541 Unicode properties are specified by C<\p{...}>. But if the name is a
1542 single character one, the braces may be omitted.
1544 =item Character in 'C' format wrapped in pack
1550 where $x is either less than 0 or more than 255; the C<"C"> format is
1551 only for encoding native operating system characters (ASCII, EBCDIC,
1552 and so on) and not for Unicode characters, so Perl behaved as if you meant
1556 If you actually want to pack Unicode codepoints, use the C<"U"> format
1559 =item Character in 'c' format wrapped in pack
1565 where $x is either less than -128 or more than 127; the C<"c"> format
1566 is only for encoding native operating system characters (ASCII, EBCDIC,
1567 and so on) and not for Unicode characters, so Perl behaved as if you meant
1569 pack("c", $x & 255);
1571 If you actually want to pack Unicode codepoints, use the C<"U"> format
1574 =item Character in '%c' format wrapped in unpack
1576 (W unpack) You tried something like
1578 unpack("H", "\x{2a1}")
1580 where the format expects to process a byte (a character with a value
1581 below 256), but a higher value was provided instead. Perl uses the
1582 value modulus 256 instead, as if you had provided:
1584 unpack("H", "\x{a1}")
1586 =item Character in 'W' format wrapped in pack
1592 where $x is either less than 0 or more than 255. However, C<U0>-mode
1593 expects all values to fall in the interval [0, 255], so Perl behaved
1596 pack("U0W", $x & 255)
1598 =item Character(s) in '%c' format wrapped in pack
1600 (W pack) You tried something like
1602 pack("u", "\x{1f3}b")
1604 where the format expects to process a sequence of bytes (character with a
1605 value below 256), but some of the characters had a higher value. Perl
1606 uses the character values modulus 256 instead, as if you had provided:
1608 pack("u", "\x{f3}b")
1610 =item Character(s) in '%c' format wrapped in unpack
1612 (W unpack) You tried something like
1614 unpack("s", "\x{1f3}b")
1616 where the format expects to process a sequence of bytes (character with a
1617 value below 256), but some of the characters had a higher value. Perl
1618 uses the character values modulus 256 instead, as if you had provided:
1620 unpack("s", "\x{f3}b")
1622 =item charnames alias definitions may not contain a sequence of multiple spaces
1624 (F) You defined a character name which had multiple space characters
1625 in a row. Change them to single spaces. Usually these names are
1626 defined in the C<:alias> import argument to C<use charnames>, but they
1627 could be defined by a translator installed into C<$^H{charnames}>. See
1628 L<charnames/CUSTOM ALIASES>.
1630 =item charnames alias definitions may not contain trailing white-space
1632 (F) You defined a character name which ended in a space
1633 character. Remove the trailing space(s). Usually these names are
1634 defined in the C<:alias> import argument to C<use charnames>, but they
1635 could be defined by a translator installed into C<$^H{charnames}>.
1636 See L<charnames/CUSTOM ALIASES>.
1638 =item chdir() on unopened filehandle %s
1640 (W unopened) You tried chdir() on a filehandle that was never opened.
1642 =item "\c%c" is more clearly written simply as "%s"
1644 (W syntax) The C<\cI<X>> construct is intended to be a way to specify
1645 non-printable characters. You used it for a printable one, which
1646 is better written as simply itself, perhaps preceded by a backslash
1647 for non-word characters. Doing it the way you did is not portable
1648 between ASCII and EBCDIC platforms.
1650 =item Cloning substitution context is unimplemented
1652 (F) Creating a new thread inside the C<s///> operator is not supported.
1654 =item closedir() attempted on invalid dirhandle %s
1656 (W io) The dirhandle you tried to close is either closed or not really
1657 a dirhandle. Check your control flow.
1659 =item close() on unopened filehandle %s
1661 (W unopened) You tried to close a filehandle that was never opened.
1663 =item Closure prototype called
1665 (F) If a closure has attributes, the subroutine passed to an attribute
1666 handler is the prototype that is cloned when a new closure is created.
1667 This subroutine cannot be called.
1669 =item \C no longer supported in regex; marked by S<<-- HERE> in m/%s/
1671 (F) The \C character class used to allow a match of single byte
1672 within a multi-byte utf-8 character, but was removed in v5.24 as
1673 it broke encapsulation and its implementation was extremely buggy.
1674 If you really need to process the individual bytes, you probably
1675 want to convert your string to one where each underlying byte is
1676 stored as a character, with utf8::encode().
1678 =item Code missing after '/'
1680 (F) You had a (sub-)template that ends with a '/'. There must be
1681 another template code following the slash. See L<perlfunc/pack>.
1683 =item Code point 0x%X is not Unicode, and not portable
1685 (S non_unicode) You had a code point that has never been in any
1686 standard, so it is likely that languages other than Perl will NOT
1687 understand it. At one time, it was legal in some standards to have code
1688 points up to 0x7FFF_FFFF, but not higher, and this code point is higher.
1690 Acceptance of these code points is a Perl extension, and you should
1691 expect that nothing other than Perl can handle them; Perl itself on
1692 EBCDIC platforms before v5.24 does not handle them.
1694 Code points above 0xFFFF_FFFF require larger than a 32 bit word.
1696 Perl also makes no guarantees that the representation of these code
1697 points won't change at some point in the future, say when machines
1698 become available that have larger than a 64-bit word. At that time,
1699 files written by an older Perl would require conversion before being
1700 readable by a newer Perl.
1702 =item Code point 0x%X is not Unicode, may not be portable
1704 (S non_unicode) You had a code point above the Unicode maximum
1707 Perl allows strings to contain a superset of Unicode code points, but
1708 these may not be accepted by other languages/systems. Further, even if
1709 these languages/systems accept these large code points, they may have
1710 chosen a different representation for them than the UTF-8-like one that
1711 Perl has, which would mean files are not exchangeable between them and
1714 On EBCDIC platforms, code points above 0x3FFF_FFFF have a different
1715 representation in Perl v5.24 than before, so any file containing these
1716 that was written before that version will require conversion before
1717 being readable by a later Perl.
1719 =item %s: Command not found
1721 (A) You've accidentally run your script through B<csh> or another shell
1722 instead of Perl. Check the #! line, or manually feed your script into
1723 Perl yourself. The #! line at the top of your file could look like
1727 =item %s: command not found
1729 (A) You've accidentally run your script through B<bash> or another shell
1730 instead of Perl. Check the #! line, or manually feed your script into
1731 Perl yourself. The #! line at the top of your file could look like
1735 =item %s: command not found: %s
1737 (A) You've accidentally run your script through B<zsh> or another shell
1738 instead of Perl. Check the #! line, or manually feed your script into
1739 Perl yourself. The #! line at the top of your file could look like
1743 =item Compilation failed in require
1745 (F) Perl could not compile a file specified in a C<require> statement.
1746 Perl uses this generic message when none of the errors that it
1747 encountered were severe enough to halt compilation immediately.
1749 =item Complex regular subexpression recursion limit (%d) exceeded
1751 (W regexp) The regular expression engine uses recursion in complex
1752 situations where back-tracking is required. Recursion depth is limited
1753 to 32766, or perhaps less in architectures where the stack cannot grow
1754 arbitrarily. ("Simple" and "medium" situations are handled without
1755 recursion and are not subject to a limit.) Try shortening the string
1756 under examination; looping in Perl code (e.g. with C<while>) rather than
1757 in the regular expression engine; or rewriting the regular expression so
1758 that it is simpler or backtracks less. (See L<perlfaq2> for information
1759 on I<Mastering Regular Expressions>.)
1761 =item connect() on closed socket %s
1763 (W closed) You tried to do a connect on a closed socket. Did you forget
1764 to check the return value of your socket() call? See
1765 L<perlfunc/connect>.
1767 =item Constant(%s): Call to &{$^H{%s}} did not return a defined value
1769 (F) The subroutine registered to handle constant overloading
1770 (see L<overload>) or a custom charnames handler (see
1771 L<charnames/CUSTOM TRANSLATORS>) returned an undefined value.
1773 =item Constant(%s): $^H{%s} is not defined
1775 (F) The parser found inconsistencies while attempting to define an
1776 overloaded constant. Perhaps you forgot to load the corresponding
1779 =item Constant is not %s reference
1781 (F) A constant value (perhaps declared using the C<use constant> pragma)
1782 is being dereferenced, but it amounts to the wrong type of reference.
1783 The message indicates the type of reference that was expected. This
1784 usually indicates a syntax error in dereferencing the constant value.
1785 See L<perlsub/"Constant Functions"> and L<constant>.
1787 =item Constants from lexical variables potentially modified elsewhere are
1788 deprecated. This will not be allowed in Perl 5.32
1790 (D deprecated) You wrote something like
1793 $sub = sub () { $var };
1795 but $var is referenced elsewhere and could be modified after the C<sub>
1796 expression is evaluated. Either it is explicitly modified elsewhere
1797 (C<$var = 3>) or it is passed to a subroutine or to an operator like
1798 C<printf> or C<map>, which may or may not modify the variable.
1800 Traditionally, Perl has captured the value of the variable at that
1801 point and turned the subroutine into a constant eligible for inlining.
1802 In those cases where the variable can be modified elsewhere, this
1803 breaks the behavior of closures, in which the subroutine captures
1804 the variable itself, rather than its value, so future changes to the
1805 variable are reflected in the subroutine's return value.
1807 This usage is deprecated, and will no longer be allowed in Perl 5.32,
1808 making it possible to change the behavior in the future.
1810 If you intended for the subroutine to be eligible for inlining, then
1811 make sure the variable is not referenced elsewhere, possibly by
1815 $sub = sub () { $var2 };
1817 If you do want this subroutine to be a closure that reflects future
1818 changes to the variable that it closes over, add an explicit C<return>:
1821 $sub = sub () { return $var };
1823 =item Constant subroutine %s redefined
1825 (W redefine)(S) You redefined a subroutine which had previously
1826 been eligible for inlining. See L<perlsub/"Constant Functions">
1827 for commentary and workarounds.
1829 =item Constant subroutine %s undefined
1831 (W misc) You undefined a subroutine which had previously been eligible
1832 for inlining. See L<perlsub/"Constant Functions"> for commentary and
1835 =item Constant(%s) unknown
1837 (F) The parser found inconsistencies either while attempting
1838 to define an overloaded constant, or when trying to find the
1839 character name specified in the C<\N{...}> escape. Perhaps you
1840 forgot to load the corresponding L<overload> pragma?
1842 =item :const is experimental
1844 (S experimental::const_attr) The "const" attribute is experimental.
1845 If you want to use the feature, disable the warning with C<no warnings
1846 'experimental::const_attr'>, but know that in doing so you are taking
1847 the risk that your code may break in a future Perl version.
1849 =item :const is not permitted on named subroutines
1851 (F) The "const" attribute causes an anonymous subroutine to be run and
1852 its value captured at the time that it is cloned. Named subroutines are
1853 not cloned like this, so the attribute does not make sense on them.
1855 =item Copy method did not return a reference
1857 (F) The method which overloads "=" is buggy. See
1858 L<overload/Copy Constructor>.
1860 =item &CORE::%s cannot be called directly
1862 (F) You tried to call a subroutine in the C<CORE::> namespace
1863 with C<&foo> syntax or through a reference. Some subroutines
1864 in this package cannot yet be called that way, but must be
1865 called as barewords. Something like this will work:
1867 BEGIN { *shove = \&CORE::push; }
1868 shove @array, 1,2,3; # pushes on to @array
1870 =item CORE::%s is not a keyword
1872 (F) The CORE:: namespace is reserved for Perl keywords.
1874 =item Corrupted regexp opcode %d > %d
1876 (P) This is either an error in Perl, or, if you're using
1877 one, your L<custom regular expression engine|perlreapi>. If not the
1878 latter, report the problem through the L<perlbug> utility.
1880 =item corrupted regexp pointers
1882 (P) The regular expression engine got confused by what the regular
1883 expression compiler gave it.
1885 =item corrupted regexp program
1887 (P) The regular expression engine got passed a regexp program without a
1890 =item Corrupt malloc ptr 0x%x at 0x%x
1892 (P) The malloc package that comes with Perl had an internal failure.
1894 =item Count after length/code in unpack
1896 (F) You had an unpack template indicating a counted-length string, but
1897 you have also specified an explicit size for the string. See
1900 =item Declaring references is experimental
1902 (S experimental::declared_refs) This warning is emitted if you use
1903 a reference constructor on the right-hand side of C<my>, C<state>, C<our>, or
1904 C<local>. Simply suppress the warning if you want to use the feature, but
1905 know that in doing so you are taking the risk of using an experimental
1906 feature which may change or be removed in a future Perl version:
1908 no warnings "experimental::declared_refs";
1909 use feature "declared_refs";
1913 The following are used in lib/diagnostics.t for testing two =items that
1914 share the same description. Changes here need to be propagated to there
1916 =item Deep recursion on anonymous subroutine
1918 =item Deep recursion on subroutine "%s"
1920 (W recursion) This subroutine has called itself (directly or indirectly)
1921 100 times more than it has returned. This probably indicates an
1922 infinite recursion, unless you're writing strange benchmark programs, in
1923 which case it indicates something else.
1925 This threshold can be changed from 100, by recompiling the F<perl> binary,
1926 setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1928 =item (?(DEFINE)....) does not allow branches in regex; marked by
1929 S<<-- HERE> in m/%s/
1931 (F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
1932 most likely cause of this error is that you left out a parenthesis inside
1933 of the C<....> part.
1935 The S<<-- HERE> shows whereabouts in the regular expression the problem was
1938 =item %s defines neither package nor VERSION--version check failed
1940 (F) You said something like "use Module 42" but in the Module file
1941 there are neither package declarations nor a C<$VERSION>.
1943 =item delete argument is not a HASH or ARRAY element or slice
1945 (F) The argument to C<delete> must be either a hash or array element,
1951 or a hash or array slice, such as:
1953 @foo[$bar, $baz, $xyzzy]
1954 @{$ref->[12]}{"susie", "queue"}
1956 or a hash key/value or array index/value slice, such as:
1958 %foo[$bar, $baz, $xyzzy]
1959 %{$ref->[12]}{"susie", "queue"}
1961 =item Delimiter for here document is too long
1963 (F) In a here document construct like C<<<FOO>, the label C<FOO> is too
1964 long for Perl to handle. You have to be seriously twisted to write code
1965 that triggers this error.
1967 =item Deprecated use of my() in false conditional. This will be a fatal error in Perl 5.30
1969 (D deprecated) You used a declaration similar to C<my $x if 0>. There
1970 has been a long-standing bug in Perl that causes a lexical variable
1971 not to be cleared at scope exit when its declaration includes a false
1972 conditional. Some people have exploited this bug to achieve a kind of
1973 static variable. Since we intend to fix this bug, we don't want people
1974 relying on this behavior. You can achieve a similar static effect by
1975 declaring the variable in a separate block outside the function, eg
1977 sub f { my $x if 0; return $x++ }
1981 { my $x; sub f { return $x++ } }
1983 Beginning with perl 5.10.0, you can also use C<state> variables to have
1984 lexicals that are initialized only once (see L<feature>):
1986 sub f { state $x; return $x++ }
1988 This use of C<my()> in a false conditional has been deprecated since
1989 Perl 5.10, and it will become a fatal error in Perl 5.30.
1991 =item DESTROY created new reference to dead object '%s'
1993 (F) A DESTROY() method created a new reference to the object which is
1994 just being DESTROYed. Perl is confused, and prefers to abort rather
1995 than to create a dangling reference.
1997 =item Did not produce a valid header
1999 See L</500 Server error>.
2001 =item %s did not return a true value
2003 (F) A required (or used) file must return a true value to indicate that
2004 it compiled correctly and ran its initialization code correctly. It's
2005 traditional to end such a file with a "1;", though any true value would
2006 do. See L<perlfunc/require>.
2008 =item (Did you mean &%s instead?)
2010 (W misc) You probably referred to an imported subroutine &FOO as $FOO or
2013 =item (Did you mean "local" instead of "our"?)
2015 (W misc) Remember that "our" does not localize the declared global
2016 variable. You have declared it again in the same lexical scope, which
2019 =item (Did you mean $ or @ instead of %?)
2021 (W) You probably said %hash{$key} when you meant $hash{$key} or
2022 @hash{@keys}. On the other hand, maybe you just meant %hash and got
2027 (F) You passed die() an empty string (the equivalent of C<die "">) or
2028 you called it with no args and C<$@> was empty.
2030 =item Document contains no data
2032 See L</500 Server error>.
2034 =item %s does not define %s::VERSION--version check failed
2036 (F) You said something like "use Module 42" but the Module did not
2037 define a C<$VERSION>.
2039 =item '/' does not take a repeat count
2041 (F) You cannot put a repeat count of any kind right after the '/' code.
2042 See L<perlfunc/pack>.
2044 =item do "%s" failed, '.' is no longer in @INC; did you mean do "./%s"?
2046 (D deprecated) Previously C< do "somefile"; > would search the current
2047 directory for the specified file. Since perl v5.26.0, F<.> has been
2048 removed from C<@INC> by default, so this is no longer true. To search the
2049 current directory (and only the current directory) you can write
2050 C< do "./somefile"; >.
2052 =item Don't know how to get file name
2054 (P) C<PerlIO_getname>, a perl internal I/O function specific to VMS, was
2055 somehow called on another platform. This should not happen.
2057 =item Don't know how to handle magic of type \%o
2059 (P) The internal handling of magical variables has been cursed.
2061 =item do_study: out of memory
2063 (P) This should have been caught by safemalloc() instead.
2065 =item (Do you need to predeclare %s?)
2067 (S syntax) This is an educated guess made in conjunction with the message
2068 "%s found where operator expected". It often means a subroutine or module
2069 name is being referenced that hasn't been declared yet. This may be
2070 because of ordering problems in your file, or because of a missing
2071 "sub", "package", "require", or "use" statement. If you're referencing
2072 something that isn't defined yet, you don't actually have to define the
2073 subroutine or package before the current location. You can use an empty
2074 "sub foo;" or "package FOO;" to enter a "forward" declaration.
2076 =item dump() better written as CORE::dump(). dump() will no longer be available in Perl 5.30
2078 (D deprecated, misc) You used the obsolescent C<dump()> built-in function,
2079 without fully qualifying it as C<CORE::dump()>. Maybe it's a typo.
2081 Use of a unqualified C<dump()> was deprecated in Perl 5.8.0, and this
2082 will not be available in Perl 5.30.
2084 See L<perlfunc/dump>.
2086 =item dump is not supported
2088 (F) Your machine doesn't support dump/undump.
2090 =item Duplicate free() ignored
2092 (S malloc) An internal routine called free() on something that had
2095 =item Duplicate modifier '%c' after '%c' in %s
2097 (W unpack) You have applied the same modifier more than once after a
2098 type in a pack template. See L<perlfunc/pack>.
2100 =item elseif should be elsif
2102 (S syntax) There is no keyword "elseif" in Perl because Larry thinks
2103 it's ugly. Your code will be interpreted as an attempt to call a method
2104 named "elseif" for the class returned by the following block. This is
2105 unlikely to be what you want.
2107 =item Empty \%c in regex; marked by S<<-- HERE> in m/%s/
2109 =item Empty \%c{} in regex; marked by S<<-- HERE> in m/%s/
2111 (F) C<\p> and C<\P> are used to introduce a named Unicode property, as
2112 described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
2113 a regular expression without specifying the property name.
2115 =item ${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28
2117 (D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
2118 the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
2120 Setting this variable will become a fatal error in Perl 5.28.
2122 =item entering effective %s failed
2124 (F) While under the C<use filetest> pragma, switching the real and
2125 effective uids or gids failed.
2127 =item %ENV is aliased to %s
2129 (F) You're running under taint mode, and the C<%ENV> variable has been
2130 aliased to another hash, so it doesn't reflect anymore the state of the
2131 program's environment. This is potentially insecure.
2133 =item Error converting file specification %s
2135 (F) An error peculiar to VMS. Because Perl may have to deal with file
2136 specifications in either VMS or Unix syntax, it converts them to a
2137 single form when it must operate on them directly. Either you've passed
2138 an invalid file specification to Perl, or you've found a case the
2139 conversion routines don't handle. Drat.
2141 =item Eval-group in insecure regular expression
2143 (F) Perl detected tainted data when trying to compile a regular
2144 expression that contains the C<(?{ ... })> zero-width assertion, which
2145 is unsafe. See L<perlre/(?{ code })>, and L<perlsec>.
2147 =item Eval-group not allowed at runtime, use re 'eval' in regex m/%s/
2149 (F) Perl tried to compile a regular expression containing the
2150 C<(?{ ... })> zero-width assertion at run time, as it would when the
2151 pattern contains interpolated values. Since that is a security risk,
2152 it is not allowed. If you insist, you may still do this by using the
2153 C<re 'eval'> pragma or by explicitly building the pattern from an
2154 interpolated string at run time and using that in an eval(). See
2155 L<perlre/(?{ code })>.
2157 =item Eval-group not allowed, use re 'eval' in regex m/%s/
2159 (F) A regular expression contained the C<(?{ ... })> zero-width
2160 assertion, but that construct is only allowed when the C<use re 'eval'>
2161 pragma is in effect. See L<perlre/(?{ code })>.
2163 =item EVAL without pos change exceeded limit in regex; marked by
2164 S<<-- HERE> in m/%s/
2166 (F) You used a pattern that nested too many EVAL calls without consuming
2167 any text. Restructure the pattern so that text is consumed.
2169 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2172 =item Excessively long <> operator
2174 (F) The contents of a <> operator may not exceed the maximum size of a
2175 Perl identifier. If you're just trying to glob a long list of
2176 filenames, try using the glob() operator, or put the filenames into a
2177 variable and glob that.
2179 =item exec? I'm not *that* kind of operating system
2181 (F) The C<exec> function is not implemented on some systems, e.g., Symbian
2182 OS. See L<perlport>.
2184 =item %sExecution of %s aborted due to compilation errors.
2186 (F) The final summary message when a Perl compilation fails.
2188 =item exists argument is not a HASH or ARRAY element or a subroutine
2190 (F) The argument to C<exists> must be a hash or array element or a
2191 subroutine with an ampersand, such as:
2197 =item exists argument is not a subroutine name
2199 (F) The argument to C<exists> for C<exists &sub> must be a subroutine name,
2200 and not a subroutine call. C<exists &sub()> will generate this error.
2202 =item Exiting eval via %s
2204 (W exiting) You are exiting an eval by unconventional means, such as a
2205 goto, or a loop control statement.
2207 =item Exiting format via %s
2209 (W exiting) You are exiting a format by unconventional means, such as a
2210 goto, or a loop control statement.
2212 =item Exiting pseudo-block via %s
2214 (W exiting) You are exiting a rather special block construct (like a
2215 sort block or subroutine) by unconventional means, such as a goto, or a
2216 loop control statement. See L<perlfunc/sort>.
2218 =item Exiting subroutine via %s
2220 (W exiting) You are exiting a subroutine by unconventional means, such
2221 as a goto, or a loop control statement.
2223 =item Exiting substitution via %s
2225 (W exiting) You are exiting a substitution by unconventional means, such
2226 as a return, a goto, or a loop control statement.
2228 =item Expecting close bracket in regex; marked by S<<-- HERE> in m/%s/
2230 (F) You wrote something like
2234 to denote a capturing group of the form
2235 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>,
2236 but omitted the C<")">.
2238 =item Expecting '(?flags:(?[...' in regex; marked by S<<-- HERE> in m/%s/
2240 (F) The C<(?[...])> extended character class regular expression construct
2241 only allows character classes (including character class escapes like
2242 C<\d>), operators, and parentheses. The one exception is C<(?flags:...)>
2243 containing at least one flag and exactly one C<(?[...])> construct.
2244 This allows a regular expression containing just C<(?[...])> to be
2245 interpolated. If you see this error message, then you probably
2246 have some other C<(?...)> construct inside your character class. See
2247 L<perlrecharclass/Extended Bracketed Character Classes>.
2249 =item Experimental aliasing via reference not enabled
2251 (F) To do aliasing via references, you must first enable the feature:
2253 no warnings "experimental::refaliasing";
2254 use feature "refaliasing";
2257 =item Experimental %s on scalar is now forbidden
2259 (F) An experimental feature added in Perl 5.14 allowed C<each>, C<keys>,
2260 C<push>, C<pop>, C<shift>, C<splice>, C<unshift>, and C<values> to be called with a
2261 scalar argument. This experiment is considered unsuccessful, and
2262 has been removed. The C<postderef> feature may meet your needs better.
2264 =item Experimental subroutine signatures not enabled
2266 (F) To use subroutine signatures, you must first enable them:
2268 no warnings "experimental::signatures";
2269 use feature "signatures";
2270 sub foo ($left, $right) { ... }
2272 =item Explicit blessing to '' (assuming package main)
2274 (W misc) You are blessing a reference to a zero length string. This has
2275 the effect of blessing the reference into the package main. This is
2276 usually not what you want. Consider providing a default target package,
2277 e.g. bless($ref, $p || 'MyPackage');
2279 =item %s: Expression syntax
2281 (A) You've accidentally run your script through B<csh> instead of Perl.
2282 Check the #! line, or manually feed your script into Perl yourself.
2284 =item %s failed--call queue aborted
2286 (F) An untrapped exception was raised while executing a UNITCHECK,
2287 CHECK, INIT, or END subroutine. Processing of the remainder of the
2288 queue of such routines has been prematurely ended.
2290 =item Failed to close in-place edit file %s: %s
2292 (F) Closing an output file from in-place editing, as with the C<-i>
2293 command-line switch, failed.
2295 =item False [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2297 (W regexp)(F) A character class range must start and end at a literal
2298 character, not another character class like C<\d> or C<[:alpha:]>. The "-"
2299 in your false range is interpreted as a literal "-". In a C<(?[...])>
2300 construct, this is an error, rather than a warning. Consider quoting
2301 the "-", "\-". The S<<-- HERE> shows whereabouts in the regular expression
2302 the problem was discovered. See L<perlre>.
2304 =item Fatal VMS error (status=%d) at %s, line %d
2306 (P) An error peculiar to VMS. Something untoward happened in a VMS
2307 system service or RTL routine; Perl's exit status should provide more
2308 details. The filename in "at %s" and the line number in "line %d" tell
2309 you which section of the Perl source code is distressed.
2311 =item fcntl is not implemented
2313 (F) Your machine apparently doesn't implement fcntl(). What is this, a
2314 PDP-11 or something?
2316 =item FETCHSIZE returned a negative value
2318 (F) A tied array claimed to have a negative number of elements, which
2321 =item Field too wide in 'u' format in pack
2323 (W pack) Each line in an uuencoded string starts with a length indicator
2324 which can't encode values above 63. So there is no point in asking for
2325 a line length bigger than that. Perl will behave as if you specified
2326 C<u63> as the format.
2328 =item File::Glob::glob() will disappear in perl 5.30. Use File::Glob::bsd_glob() instead.
2330 (D deprecated) C<< File::Glob >> has a function called C<< glob >>, which
2331 just calls C<< bsd_glob >>. However, its prototype is different from the
2332 prototype of C<< CORE::glob >>, and hence, C<< File::Glob::glob >> should
2335 C<< File::Glob::glob() >> was deprecated in perl 5.8.0. A deprecation
2336 message was issued from perl 5.26.0 onwards, and the function will
2337 disappear in perl 5.30.0.
2339 Code using C<< File::Glob::glob() >> should call
2340 C<< File::Glob::bsd_glob() >> instead.
2342 =item Filehandle %s opened only for input
2344 (W io) You tried to write on a read-only filehandle. If you intended
2345 it to be a read-write filehandle, you needed to open it with "+<" or
2346 "+>" or "+>>" instead of with "<" or nothing. If you intended only to
2347 write the file, use ">" or ">>". See L<perlfunc/open>.
2349 =item Filehandle %s opened only for output
2351 (W io) You tried to read from a filehandle opened only for writing, If
2352 you intended it to be a read/write filehandle, you needed to open it
2353 with "+<" or "+>" or "+>>" instead of with ">". If you intended only to
2354 read from the file, use "<". See L<perlfunc/open>. Another possibility
2355 is that you attempted to open filedescriptor 0 (also known as STDIN) for
2356 output (maybe you closed STDIN earlier?).
2358 =item Filehandle %s reopened as %s only for input
2360 (W io) You opened for reading a filehandle that got the same filehandle id
2361 as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR
2364 =item Filehandle STDIN reopened as %s only for output
2366 (W io) You opened for writing a filehandle that got the same filehandle id
2367 as STDIN. This occurred because you closed STDIN previously.
2369 =item Final $ should be \$ or $name
2371 (F) You must now decide whether the final $ in a string was meant to be
2372 a literal dollar sign, or was meant to introduce a variable name that
2373 happens to be missing. So you have to put either the backslash or the
2376 =item flock() on closed filehandle %s
2378 (W closed) The filehandle you're attempting to flock() got itself closed
2379 some time before now. Check your control flow. flock() operates on
2380 filehandles. Are you attempting to call flock() on a dirhandle by the
2383 =item Format not terminated
2385 (F) A format must be terminated by a line with a solitary dot. Perl got
2386 to the end of your file without finding such a line.
2388 =item Format %s redefined
2390 (W redefine) You redefined a format. To suppress this warning, say
2393 no warnings 'redefine';
2394 eval "format NAME =...";
2397 =item Found = in conditional, should be ==
2407 (or something like that).
2409 =item %s found where operator expected
2411 (S syntax) The Perl lexer knows whether to expect a term or an operator.
2412 If it sees what it knows to be a term when it was expecting to see an
2413 operator, it gives you this warning. Usually it indicates that an
2414 operator or delimiter was omitted, such as a semicolon.
2416 =item gdbm store returned %d, errno %d, key "%s"
2418 (S) A warning from the GDBM_File extension that a store failed.
2420 =item gethostent not implemented
2422 (F) Your C library apparently doesn't implement gethostent(), probably
2423 because if it did, it'd feel morally obligated to return every hostname
2426 =item get%sname() on closed socket %s
2428 (W closed) You tried to get a socket or peer socket name on a closed
2429 socket. Did you forget to check the return value of your socket() call?
2431 =item getpwnam returned invalid UIC %#o for user "%s"
2433 (S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
2434 C<getpwnam> operator returned an invalid UIC.
2436 =item getsockopt() on closed socket %s
2438 (W closed) You tried to get a socket option on a closed socket. Did you
2439 forget to check the return value of your socket() call? See
2440 L<perlfunc/getsockopt>.
2442 =item given is experimental
2444 (S experimental::smartmatch) C<given> depends on smartmatch, which
2445 is experimental, so its behavior may change or even be removed
2446 in any future release of perl. See the explanation under
2447 L<perlsyn/Experimental Details on given and when>.
2449 =item Global symbol "%s" requires explicit package name (did you forget to
2452 (F) You've said "use strict" or "use strict vars", which indicates
2453 that all variables must either be lexically scoped (using "my" or "state"),
2454 declared beforehand using "our", or explicitly qualified to say
2455 which package the global variable is in (using "::").
2457 =item glob failed (%s)
2459 (S glob) Something went wrong with the external program(s) used
2460 for C<glob> and C<< <*.c> >>. Usually, this means that you supplied a C<glob>
2461 pattern that caused the external program to fail and exit with a
2462 nonzero status. If the message indicates that the abnormal exit
2463 resulted in a coredump, this may also mean that your csh (C shell)
2464 is broken. If so, you should change all of the csh-related variables
2465 in config.sh: If you have tcsh, make the variables refer to it as
2466 if it were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them
2467 all empty (except that C<d_csh> should be C<'undef'>) so that Perl will
2468 think csh is missing. In either case, after editing config.sh, run
2469 C<./Configure -S> and rebuild Perl.
2471 =item Glob not terminated
2473 (F) The lexer saw a left angle bracket in a place where it was expecting
2474 a term, so it's looking for the corresponding right angle bracket, and
2475 not finding it. Chances are you left some needed parentheses out
2476 earlier in the line, and you really meant a "less than".
2478 =item gmtime(%f) failed
2480 (W overflow) You called C<gmtime> with a number that it could not handle:
2481 too large, too small, or NaN. The returned value is C<undef>.
2483 =item gmtime(%f) too large
2485 (W overflow) You called C<gmtime> with a number that was larger than
2486 it can reliably handle and C<gmtime> probably returned the wrong
2487 date. This warning is also triggered with NaN (the special
2488 not-a-number value).
2490 =item gmtime(%f) too small
2492 (W overflow) You called C<gmtime> with a number that was smaller than
2493 it can reliably handle and C<gmtime> probably returned the wrong date.
2495 =item Got an error from DosAllocMem
2497 (P) An error peculiar to OS/2. Most probably you're using an obsolete
2498 version of Perl, and this should not happen anyway.
2500 =item goto must have label
2502 (F) Unlike with "next" or "last", you're not allowed to goto an
2503 unspecified destination. See L<perlfunc/goto>.
2505 =item Goto undefined subroutine%s
2507 (F) You tried to call a subroutine with C<goto &sub> syntax, but
2508 the indicated subroutine hasn't been defined, or if it was, it
2509 has since been undefined.
2511 =item Group name must start with a non-digit word character in regex; marked by
2512 S<<-- HERE> in m/%s/
2514 (F) Group names must follow the rules for perl identifiers, meaning
2515 they must start with a non-digit word character. A common cause of
2516 this error is using (?&0) instead of (?0). See L<perlre>.
2518 =item ()-group starts with a count
2520 (F) A ()-group started with a count. A count is supposed to follow
2521 something: a template character or a ()-group. See L<perlfunc/pack>.
2523 =item %s had compilation errors.
2525 (F) The final summary message when a C<perl -c> fails.
2527 =item Had to create %s unexpectedly
2529 (S internal) A routine asked for a symbol from a symbol table that ought
2530 to have existed already, but for some reason it didn't, and had to be
2531 created on an emergency basis to prevent a core dump.
2533 =item %s has too many errors
2535 (F) The parser has given up trying to parse the program after 10 errors.
2536 Further error messages would likely be uninformative.
2538 =item Hexadecimal float: exponent overflow
2540 (W overflow) The hexadecimal floating point has a larger exponent
2541 than the floating point supports.
2543 =item Hexadecimal float: exponent underflow
2545 (W overflow) The hexadecimal floating point has a smaller exponent
2546 than the floating point supports. With the IEEE 754 floating point,
2547 this may also mean that the subnormals (formerly known as denormals)
2548 are being used, which may or may not be an error.
2550 =item Hexadecimal float: internal error (%s)
2552 (F) Something went horribly bad in hexadecimal float handling.
2554 =item Hexadecimal float: mantissa overflow
2556 (W overflow) The hexadecimal floating point literal had more bits in
2557 the mantissa (the part between the 0x and the exponent, also known as
2558 the fraction or the significand) than the floating point supports.
2560 =item Hexadecimal float: precision loss
2562 (W overflow) The hexadecimal floating point had internally more
2563 digits than could be output. This can be caused by unsupported
2564 long double formats, or by 64-bit integers not being available
2565 (needed to retrieve the digits under some configurations).
2567 =item Hexadecimal float: unsupported long double format
2569 (F) You have configured Perl to use long doubles but
2570 the internals of the long double format are unknown;
2571 therefore the hexadecimal float output is impossible.
2573 =item Hexadecimal number > 0xffffffff non-portable
2575 (W portable) The hexadecimal number you specified is larger than 2**32-1
2576 (4294967295) and therefore non-portable between systems. See
2577 L<perlport> for more on portability concerns.
2579 =item Identifier too long
2581 (F) Perl limits identifiers (names for variables, functions, etc.) to
2582 about 250 characters for simple names, and somewhat more for compound
2583 names (like C<$A::B>). You've exceeded Perl's limits. Future versions
2584 of Perl are likely to eliminate these arbitrary limitations.
2586 =item Ignoring zero length \N{} in character class in regex; marked by
2587 S<<-- HERE> in m/%s/
2589 (W regexp) Named Unicode character escapes (C<\N{...}>) may return a
2590 zero-length sequence. When such an escape is used in a character
2591 class its behavior is not well defined. Check that the correct
2592 escape has been used, and the correct charname handler is in scope.
2594 =item Illegal binary digit %s
2596 (F) You used a digit other than 0 or 1 in a binary number.
2598 =item Illegal binary digit %s ignored
2600 (W digit) You may have tried to use a digit other than 0 or 1 in a
2601 binary number. Interpretation of the binary number stopped before the
2604 =item Illegal character after '_' in prototype for %s : %s
2606 (W illegalproto) An illegal character was found in a prototype
2607 declaration. The '_' in a prototype must be followed by a ';',
2608 indicating the rest of the parameters are optional, or one of '@'
2609 or '%', since those two will accept 0 or more final parameters.
2611 =item Illegal character \%o (carriage return)
2613 (F) Perl normally treats carriage returns in the program text as
2614 it would any other whitespace, which means you should never see
2615 this error when Perl was built using standard options. For some
2616 reason, your version of Perl appears to have been built without
2617 this support. Talk to your Perl administrator.
2619 =item Illegal character following sigil in a subroutine signature
2621 (F) A parameter in a subroutine signature contained an unexpected character
2622 following the C<$>, C<@> or C<%> sigil character. Normally the sigil
2623 should be followed by the variable name or C<=> etc. Perhaps you are
2624 trying use a prototype while in the scope of C<use feature 'signatures'>?
2627 sub foo ($$) {} # legal - a prototype
2629 use feature 'signatures;
2630 sub foo ($$) {} # illegal - was expecting a signature
2632 :prototype($$) {} # legal
2635 =item Illegal character in prototype for %s : %s
2637 (W illegalproto) An illegal character was found in a prototype declaration.
2638 Legal characters in prototypes are $, @, %, *, ;, [, ], &, \, and +.
2639 Perhaps you were trying to write a subroutine signature but didn't enable
2640 that feature first (C<use feature 'signatures'>), so your signature was
2641 instead interpreted as a bad prototype.
2643 =item Illegal declaration of anonymous subroutine
2645 (F) When using the C<sub> keyword to construct an anonymous subroutine,
2646 you must always specify a block of code. See L<perlsub>.
2648 =item Illegal declaration of subroutine %s
2650 (F) A subroutine was not declared correctly. See L<perlsub>.
2652 =item Illegal division by zero
2654 (F) You tried to divide a number by 0. Either something was wrong in
2655 your logic, or you need to put a conditional in to guard against
2658 =item Illegal hexadecimal digit %s ignored
2660 (W digit) You may have tried to use a character other than 0 - 9 or
2661 A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
2662 number stopped before the illegal character.
2664 =item Illegal modulus zero
2666 (F) You tried to divide a number by 0 to get the remainder. Most
2667 numbers don't take to this kindly.
2669 =item Illegal number of bits in vec
2671 (F) The number of bits in vec() (the third argument) must be a power of
2672 two from 1 to 32 (or 64, if your platform supports that).
2674 =item Illegal octal digit %s
2676 (F) You used an 8 or 9 in an octal number.
2678 =item Illegal octal digit %s ignored
2680 (W digit) You may have tried to use an 8 or 9 in an octal number.
2681 Interpretation of the octal number stopped before the 8 or 9.
2683 =item Illegal pattern in regex; marked by S<<-- HERE> in m/%s/
2685 (F) You wrote something like
2689 The C<"+"> is valid only when followed by digits, indicating a
2690 capturing group. See
2691 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
2693 =item Illegal suidscript
2695 (F) The script run under suidperl was somehow illegal.
2697 =item Illegal switch in PERL5OPT: -%c
2699 (X) The PERL5OPT environment variable may only be used to set the
2700 following switches: B<-[CDIMUdmtw]>.
2702 =item Illegal user-defined property name
2704 (F) You specified a Unicode-like property name in a regular expression
2705 pattern (using C<\p{}> or C<\P{}>) that Perl knows isn't an official
2706 Unicode property, and was likely meant to be a user-defined property
2707 name, but it can't be one of those, as they must begin with either C<In>
2708 or C<Is>. Check the spelling. See also
2709 L</Can't find Unicode property definition "%s">.
2711 =item Ill-formed CRTL environ value "%s"
2713 (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
2714 internal environ array, and encountered an element without the C<=>
2715 delimiter used to separate keys from values. The element is ignored.
2717 =item Ill-formed message in prime_env_iter: |%s|
2719 (W internal) A warning peculiar to VMS. Perl tried to read a logical
2720 name or CLI symbol definition when preparing to iterate over %ENV, and
2721 didn't see the expected delimiter between key and value, so the line was
2724 =item (in cleanup) %s
2726 (W misc) This prefix usually indicates that a DESTROY() method raised
2727 the indicated exception. Since destructors are usually called by the
2728 system at arbitrary points during execution, and often a vast number of
2729 times, the warning is issued only once for any number of failures that
2730 would otherwise result in the same message being repeated.
2732 Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
2733 also result in this warning. See L<perlcall/G_KEEPERR>.
2735 =item Incomplete expression within '(?[ ])' in regex; marked by S<<-- HERE>
2738 (F) There was a syntax error within the C<(?[ ])>. This can happen if the
2739 expression inside the construct was completely empty, or if there are
2740 too many or few operands for the number of operators. Perl is not smart
2741 enough to give you a more precise indication as to what is wrong.
2743 =item Inconsistent hierarchy during C3 merge of class '%s': merging failed on
2746 (F) The method resolution order (MRO) of the given class is not
2747 C3-consistent, and you have enabled the C3 MRO for this class. See the C3
2748 documentation in L<mro> for more information.
2750 =item Indentation on line %d of here-doc doesn't match delimiter
2752 (F) You have an indented here-document where one or more of its lines
2753 have whitespace at the beginning that does not match the closing
2756 For example, line 2 below is wrong because it does not have at least
2757 2 spaces, but lines 1 and 3 are fine because they have at least 2:
2767 Note that tabs and spaces are compared strictly, meaning 1 tab will
2770 =item Infinite recursion in regex
2772 (F) You used a pattern that references itself without consuming any input
2773 text. You should check the pattern to ensure that recursive patterns
2774 either consume text or fail.
2776 =item Initialization of state variables in list context currently forbidden
2778 (F) C<state> only permits initializing a single scalar variable, in scalar
2779 context. So C<state $a = 42> is allowed, but not C<state ($a) = 42>. To apply
2780 state semantics to a hash or array, store a hash or array reference in a
2783 =item %%s[%s] in scalar context better written as $%s[%s]
2785 (W syntax) In scalar context, you've used an array index/value slice
2786 (indicated by %) to select a single element of an array. Generally
2787 it's better to ask for a scalar value (indicated by $). The difference
2788 is that C<$foo[&bar]> always behaves like a scalar, both in the value it
2789 returns and when evaluating its argument, while C<%foo[&bar]> provides
2790 a list context to its subscript, which can do weird things if you're
2791 expecting only one subscript. When called in list context, it also
2792 returns the index (what C<&bar> returns) in addition to the value.
2794 =item %%s{%s} in scalar context better written as $%s{%s}
2796 (W syntax) In scalar context, you've used a hash key/value slice
2797 (indicated by %) to select a single element of a hash. Generally it's
2798 better to ask for a scalar value (indicated by $). The difference
2799 is that C<$foo{&bar}> always behaves like a scalar, both in the value
2800 it returns and when evaluating its argument, while C<@foo{&bar}> and
2801 provides a list context to its subscript, which can do weird things
2802 if you're expecting only one subscript. When called in list context,
2803 it also returns the key in addition to the value.
2805 =item Insecure dependency in %s
2807 (F) You tried to do something that the tainting mechanism didn't like.
2808 The tainting mechanism is turned on when you're running setuid or
2809 setgid, or when you specify B<-T> to turn it on explicitly. The
2810 tainting mechanism labels all data that's derived directly or indirectly
2811 from the user, who is considered to be unworthy of your trust. If any
2812 such data is used in a "dangerous" operation, you get this error. See
2813 L<perlsec> for more information.
2815 =item Insecure directory in %s
2817 (F) You can't use system(), exec(), or a piped open in a setuid or
2818 setgid script if C<$ENV{PATH}> contains a directory that is writable by
2819 the world. Also, the PATH must not contain any relative directory.
2822 =item Insecure $ENV{%s} while running %s
2824 (F) You can't use system(), exec(), or a piped open in a setuid or
2825 setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
2826 C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
2827 supplied (or potentially supplied) by the user. The script must set
2828 the path to a known value, using trustworthy data. See L<perlsec>.
2830 =item Insecure user-defined property %s
2832 (F) Perl detected tainted data when trying to compile a regular
2833 expression that contains a call to a user-defined character property
2834 function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2835 See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
2837 =item Integer overflow in format string for %s
2839 (F) The indexes and widths specified in the format string of C<printf()>
2840 or C<sprintf()> are too large. The numbers must not overflow the size of
2841 integers for your architecture.
2843 =item Integer overflow in %s number
2845 (S overflow) The hexadecimal, octal or binary number you have specified
2846 either as a literal or as an argument to hex() or oct() is too big for
2847 your architecture, and has been converted to a floating point number.
2848 On a 32-bit architecture the largest hexadecimal, octal or binary number
2849 representable without overflow is 0xFFFFFFFF, 037777777777, or
2850 0b11111111111111111111111111111111 respectively. Note that Perl
2851 transparently promotes all numbers to a floating point representation
2852 internally--subject to loss of precision errors in subsequent
2855 =item Integer overflow in srand
2857 (S overflow) The number you have passed to srand is too big to fit
2858 in your architecture's integer representation. The number has been
2859 replaced with the largest integer supported (0xFFFFFFFF on 32-bit
2860 architectures). This means you may be getting less randomness than
2861 you expect, because different random seeds above the maximum will
2862 return the same sequence of random numbers.
2864 =item Integer overflow in version
2866 =item Integer overflow in version %d
2868 (W overflow) Some portion of a version initialization is too large for
2869 the size of integers for your architecture. This is not a warning
2870 because there is no rational reason for a version to try and use an
2871 element larger than typically 2**32. This is usually caused by trying
2872 to use some odd mathematical operation as a version, like 100/9.
2874 =item Internal disaster in regex; marked by S<<-- HERE> in m/%s/
2876 (P) Something went badly wrong in the regular expression parser.
2877 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2880 =item Internal inconsistency in tracking vforks
2882 (S) A warning peculiar to VMS. Perl keeps track of the number of times
2883 you've called C<fork> and C<exec>, to determine whether the current call
2884 to C<exec> should affect the current script or a subprocess (see
2885 L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
2886 Perl is making a guess and treating this C<exec> as a request to
2887 terminate the Perl script and execute the specified command.
2889 =item internal %<num>p might conflict with future printf extensions
2891 (S internal) Perl's internal routine that handles C<printf> and C<sprintf>
2892 formatting follows a slightly different set of rules when called from
2893 C or XS code. Specifically, formats consisting of digits followed
2894 by "p" (e.g., "%7p") are reserved for future use. If you see this
2895 message, then an XS module tried to call that routine with one such
2898 =item Internal urp in regex; marked by S<<-- HERE> in m/%s/
2900 (P) Something went badly awry in the regular expression parser. The
2901 S<<-- HERE> shows whereabouts in the regular expression the problem was
2904 =item %s (...) interpreted as function
2906 (W syntax) You've run afoul of the rule that says that any list operator
2907 followed by parentheses turns into a function, with all the list
2908 operators arguments found inside the parentheses. See
2909 L<perlop/Terms and List Operators (Leftward)>.
2911 =item In '(?...)', the '(' and '?' must be adjacent in regex;
2912 marked by S<<-- HERE> in m/%s/
2914 (F) The two-character sequence C<"(?"> in this context in a regular
2915 expression pattern should be an indivisible token, with nothing
2916 intervening between the C<"("> and the C<"?">, but you separated them
2919 =item Invalid %s attribute: %s
2921 (F) The indicated attribute for a subroutine or variable was not recognized
2922 by Perl or by a user-supplied handler. See L<attributes>.
2924 =item Invalid %s attributes: %s
2926 (F) The indicated attributes for a subroutine or variable were not
2927 recognized by Perl or by a user-supplied handler. See L<attributes>.
2929 =item Invalid character in charnames alias definition; marked by
2932 (F) You tried to create a custom alias for a character name, with
2933 the C<:alias> option to C<use charnames> and the specified character in
2934 the indicated name isn't valid. See L<charnames/CUSTOM ALIASES>.
2936 =item Invalid \0 character in %s for %s: %s\0%s
2938 (W syscalls) Embedded \0 characters in pathnames or other system call
2939 arguments produce a warning as of 5.20. The parts after the \0 were
2940 formerly ignored by system calls.
2942 =item Invalid character in \N{...}; marked by S<<-- HERE> in \N{%s}
2944 (F) Only certain characters are valid for character names. The
2945 indicated one isn't. See L<charnames/CUSTOM ALIASES>.
2947 =item Invalid conversion in %s: "%s"
2949 (W printf) Perl does not understand the given format conversion. See
2950 L<perlfunc/sprintf>.
2952 =item Invalid escape in the specified encoding in regex; marked by
2953 S<<-- HERE> in m/%s/
2955 (W regexp)(F) The numeric escape (for example C<\xHH>) of value < 256
2956 didn't correspond to a single character through the conversion
2957 from the encoding specified by the encoding pragma.
2958 The escape was replaced with REPLACEMENT CHARACTER (U+FFFD)
2959 instead, except within S<C<(?[ ])>>, where it is a fatal error.
2960 The S<<-- HERE> shows whereabouts in the regular expression the
2961 escape was discovered.
2963 =item Invalid hexadecimal number in \N{U+...}
2965 =item Invalid hexadecimal number in \N{U+...} in regex; marked by
2966 S<<-- HERE> in m/%s/
2968 (F) The character constant represented by C<...> is not a valid hexadecimal
2969 number. Either it is empty, or you tried to use a character other than
2970 0 - 9 or A - F, a - f in a hexadecimal number.
2972 =item Invalid module name %s with -%c option: contains single ':'
2974 (F) The module argument to perl's B<-m> and B<-M> command-line options
2975 cannot contain single colons in the module name, but only in the
2976 arguments after "=". In other words, B<-MFoo::Bar=:baz> is ok, but
2977 B<-MFoo:Bar=baz> is not.
2979 =item Invalid mro name: '%s'
2981 (F) You tried to C<mro::set_mro("classname", "foo")> or C<use mro 'foo'>,
2982 where C<foo> is not a valid method resolution order (MRO). Currently,
2983 the only valid ones supported are C<dfs> and C<c3>, unless you have loaded
2984 a module that is a MRO plugin. See L<mro> and L<perlmroapi>.
2986 =item Invalid negative number (%s) in chr
2988 (W utf8) You passed a negative number to C<chr>. Negative numbers are
2989 not valid character numbers, so it returns the Unicode replacement
2992 =item Invalid number '%s' for -C option.
2994 (F) You supplied a number to the -C option that either has extra leading
2995 zeroes or overflows perl's unsigned integer representation.
2997 =item invalid option -D%c, use -D'' to see choices
2999 (S debugging) Perl was called with invalid debugger flags. Call perl
3000 with the B<-D> option with no flags to see the list of acceptable values.
3001 See also L<perlrun/-Dletters>.
3003 =item Invalid quantifier in {,} in regex; marked by S<<-- HERE> in m/%s/
3005 (F) The pattern looks like a {min,max} quantifier, but the min or max
3006 could not be parsed as a valid number - either it has leading zeroes,
3007 or it represents too big a number to cope with. The S<<-- HERE> shows
3008 where in the regular expression the problem was discovered. See L<perlre>.
3010 =item Invalid [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
3012 (F) The range specified in a character class had a minimum character
3013 greater than the maximum character. One possibility is that you forgot the
3014 C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
3015 up to C<ff>. The S<<-- HERE> shows whereabouts in the regular expression the
3016 problem was discovered. See L<perlre>.
3018 =item Invalid range "%s" in transliteration operator
3020 (F) The range specified in the tr/// or y/// operator had a minimum
3021 character greater than the maximum character. See L<perlop>.
3023 =item Invalid separator character %s in attribute list
3025 (F) Something other than a colon or whitespace was seen between the
3026 elements of an attribute list. If the previous attribute had a
3027 parenthesised parameter list, perhaps that list was terminated too soon.
3030 =item Invalid separator character %s in PerlIO layer specification %s
3032 (W layer) When pushing layers onto the Perl I/O system, something other
3033 than a colon or whitespace was seen between the elements of a layer list.
3034 If the previous attribute had a parenthesised parameter list, perhaps that
3035 list was terminated too soon.
3037 =item Invalid strict version format (%s)
3039 (F) A version number did not meet the "strict" criteria for versions.
3040 A "strict" version number is a positive decimal number (integer or
3041 decimal-fraction) without exponentiation or else a dotted-decimal
3042 v-string with a leading 'v' character and at least three components.
3043 The parenthesized text indicates which criteria were not met.
3044 See the L<version> module for more details on allowed version formats.
3046 =item Invalid type '%s' in %s
3048 (F) The given character is not a valid pack or unpack type.
3049 See L<perlfunc/pack>.
3051 (W) The given character is not a valid pack or unpack type but used to be
3054 =item Invalid version format (%s)
3056 (F) A version number did not meet the "lax" criteria for versions.
3057 A "lax" version number is a positive decimal number (integer or
3058 decimal-fraction) without exponentiation or else a dotted-decimal
3059 v-string. If the v-string has fewer than three components, it
3060 must have a leading 'v' character. Otherwise, the leading 'v' is
3061 optional. Both decimal and dotted-decimal versions may have a
3062 trailing "alpha" component separated by an underscore character
3063 after a fractional or dotted-decimal component. The parenthesized
3064 text indicates which criteria were not met. See the L<version> module
3065 for more details on allowed version formats.
3067 =item Invalid version object
3069 (F) The internal structure of the version object was invalid.
3070 Perhaps the internals were modified directly in some way or
3071 an arbitrary reference was blessed into the "version" class.
3073 =item In '(*VERB...)', the '(' and '*' must be adjacent in regex;
3074 marked by S<<-- HERE> in m/%s/
3076 (F) The two-character sequence C<"(*"> in
3077 this context in a regular expression pattern should be an
3078 indivisible token, with nothing intervening between the C<"(">
3079 and the C<"*">, but you separated them.
3081 =item ioctl is not implemented
3083 (F) Your machine apparently doesn't implement ioctl(), which is pretty
3084 strange for a machine that supports C.
3086 =item ioctl() on unopened %s
3088 (W unopened) You tried ioctl() on a filehandle that was never opened.
3089 Check your control flow and number of arguments.
3091 =item IO layers (like '%s') unavailable
3093 (F) Your Perl has not been configured to have PerlIO, and therefore
3094 you cannot use IO layers. To have PerlIO, Perl must be configured
3097 =item IO::Socket::atmark not implemented on this architecture
3099 (F) Your machine doesn't implement the sockatmark() functionality,
3100 neither as a system call nor an ioctl call (SIOCATMARK).
3102 =item '%s' is an unknown bound type in regex; marked by S<<-- HERE> in m/%s/
3104 (F) You used C<\b{...}> or C<\B{...}> and the C<...> is not known to
3105 Perl. The current valid ones are given in
3106 L<perlrebackslash/\b{}, \b, \B{}, \B>.
3108 =item %s() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30
3110 (D deprecated) The sysread(), recv(), syswrite() and send() operators are
3111 deprecated on handles that have the C<:utf8> layer, either explicitly, or
3112 implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
3114 Both sysread() and recv() currently use only the C<:utf8> flag for the stream,
3115 ignoring the actual layers. Since sysread() and recv() do no UTF-8
3116 validation they can end up creating invalidly encoded scalars.
3118 Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise ignoring
3119 any layers. If the flag is set, both write the value UTF-8 encoded, even if
3120 the layer is some different encoding, such as the example above.
3122 Ideally, all of these operators would completely ignore the C<:utf8> state,
3123 working only with bytes, but this would result in silently breaking existing
3126 In Perl 5.30, it will no longer be possible to use sysread(), recv(),
3127 syswrite() or send() to read or send bytes from/to :utf8 handles.
3129 =item "%s" is more clearly written simply as "%s" in regex; marked by S<<-- HERE> in m/%s/
3131 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
3133 You specified a character that has the given plainer way of writing it,
3134 and which is also portable to platforms running with different character
3137 =item $* is no longer supported. Its use will be fatal in Perl 5.30
3139 (D deprecated, syntax) The special variable C<$*>, deprecated in older
3140 perls, has been removed as of 5.10.0 and is no longer supported. In
3141 previous versions of perl the use of C<$*> enabled or disabled multi-line
3142 matching within a string.
3144 Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
3145 modifiers. You can enable C</m> for a lexical scope (even a whole file)
3146 with C<use re '/m'>. (In older versions: when C<$*> was set to a true value
3147 then all regular expressions behaved as if they were written using C</m>.)
3149 Use of this variable will be a fatal error in Perl 5.30.
3151 =item $# is no longer supported. Its use will be fatal in Perl 5.30
3153 (D deprecated, syntax) The special variable C<$#>, deprecated in older
3154 perls, has been removed as of 5.10.0 and is no longer supported. You
3155 should use the printf/sprintf functions instead.
3157 Use of this variable will be a fatal error in Perl 5.30.
3159 =item '%s' is not a code reference
3161 (W overload) The second (fourth, sixth, ...) argument of
3162 overload::constant needs to be a code reference. Either
3163 an anonymous subroutine, or a reference to a subroutine.
3165 =item '%s' is not an overloadable type
3167 (W overload) You tried to overload a constant type the overload package is
3170 =item -i used with no filenames on the command line, reading from STDIN
3172 (S inplace) The C<-i> option was passed on the command line, indicating
3173 that the script is intended to edit files in place, but no files were
3174 given. This is usually a mistake, since editing STDIN in place doesn't
3175 make sense, and can be confusing because it can make perl look like
3176 it is hanging when it is really just trying to read from STDIN. You
3177 should either pass a filename to edit, or remove C<-i> from the command
3178 line. See L<perlrun> for more details.
3180 =item Junk on end of regexp in regex m/%s/
3182 (P) The regular expression parser is confused.
3184 =item Label not found for "last %s"
3186 (F) You named a loop to break out of, but you're not currently in a loop
3187 of that name, not even if you count where you were called from. See
3190 =item Label not found for "next %s"
3192 (F) You named a loop to continue, but you're not currently in a loop of
3193 that name, not even if you count where you were called from. See
3196 =item Label not found for "redo %s"
3198 (F) You named a loop to restart, but you're not currently in a loop of
3199 that name, not even if you count where you were called from. See
3202 =item leaving effective %s failed
3204 (F) While under the C<use filetest> pragma, switching the real and
3205 effective uids or gids failed.
3207 =item length/code after end of string in unpack
3209 (F) While unpacking, the string buffer was already used up when an unpack
3210 length/code combination tried to obtain more data. This results in
3211 an undefined value for the length. See L<perlfunc/pack>.
3213 =item length() used on %s (did you mean "scalar(%s)"?)
3215 (W syntax) You used length() on either an array or a hash when you
3216 probably wanted a count of the items.
3218 Array size can be obtained by doing:
3222 The number of items in a hash can be obtained by doing:
3226 =item Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
3228 (F) An extension is attempting to insert text into the current parse
3229 (using L<lex_stuff_pvn|perlapi/lex_stuff_pvn> or similar), but tried to insert a character that
3230 couldn't be part of the current input. This is an inherent pitfall
3231 of the stuffing mechanism, and one of the reasons to avoid it. Where
3232 it is necessary to stuff, stuffing only plain ASCII is recommended.
3234 =item Lexing code internal error (%s)
3236 (F) Lexing code supplied by an extension violated the lexer's API in a
3239 =item listen() on closed socket %s
3241 (W closed) You tried to do a listen on a closed socket. Did you forget
3242 to check the return value of your socket() call? See
3245 =item List form of piped open not implemented
3247 (F) On some platforms, notably Windows, the three-or-more-arguments
3248 form of C<open> does not support pipes, such as C<open($pipe, '|-', @args)>.
3249 Use the two-argument C<open($pipe, '|prog arg1 arg2...')> form instead.
3251 =item %s: loadable library and perl binaries are mismatched (got handshake key %p, needed %p)
3253 (P) A dynamic loading library C<.so> or C<.dll> was being loaded into the
3254 process that was built against a different build of perl than the
3255 said library was compiled against. Reinstalling the XS module will
3256 likely fix this error.
3258 =item Locale '%s' may not work well.%s
3260 (W locale) You are using the named locale, which is a non-UTF-8 one, and
3261 which perl has determined is not fully compatible with what it can
3262 handle. The second C<%s> gives a reason.
3264 By far the most common reason is that the locale has characters in it
3265 that are represented by more than one byte. The only such locales that
3266 Perl can handle are the UTF-8 locales. Most likely the specified locale
3267 is a non-UTF-8 one for an East Asian language such as Chinese or
3268 Japanese. If the locale is a superset of ASCII, the ASCII portion of it
3271 Some essentially obsolete locales that aren't supersets of ASCII, mainly
3272 those in ISO 646 or other 7-bit locales, such as ASMO 449, can also have
3273 problems, depending on what portions of the ASCII character set get
3274 changed by the locale and are also used by the program.
3275 The warning message lists the determinable conflicting characters.
3277 Note that not all incompatibilities are found.
3279 If this happens to you, there's not much you can do except switch to use a
3280 different locale or use L<Encode> to translate from the locale into
3281 UTF-8; if that's impracticable, you have been warned that some things
3284 This message is output once each time a bad locale is switched into
3285 within the scope of C<S<use locale>>, or on the first possibly-affected
3286 operation if the C<S<use locale>> inherits a bad one. It is not raised
3287 for any operations from the L<POSIX> module.
3289 =item localtime(%f) failed
3291 (W overflow) You called C<localtime> with a number that it could not handle:
3292 too large, too small, or NaN. The returned value is C<undef>.
3294 =item localtime(%f) too large
3296 (W overflow) You called C<localtime> with a number that was larger
3297 than it can reliably handle and C<localtime> probably returned the
3298 wrong date. This warning is also triggered with NaN (the special
3299 not-a-number value).
3301 =item localtime(%f) too small
3303 (W overflow) You called C<localtime> with a number that was smaller
3304 than it can reliably handle and C<localtime> probably returned the
3307 =item Lookbehind longer than %d not implemented in regex m/%s/
3309 (F) There is currently a limit on the length of string which lookbehind can
3310 handle. This restriction may be eased in a future release.
3312 =item Lost precision when %s %f by 1
3314 (W imprecision) The value you attempted to increment or decrement by one
3315 is too large for the underlying floating point representation to store
3316 accurately, hence the target of C<++> or C<--> is unchanged. Perl issues this
3317 warning because it has already switched from integers to floating point
3318 when values are too large for integers, and now even floating point is
3319 insufficient. You may wish to switch to using L<Math::BigInt> explicitly.
3321 =item lstat() on filehandle%s
3323 (W io) You tried to do an lstat on a filehandle. What did you mean
3324 by that? lstat() makes sense only on filenames. (Perl did a fstat()
3325 instead on the filehandle.)
3327 =item lvalue attribute %s already-defined subroutine
3329 (W misc) Although L<attributes.pm|attributes> allows this, turning the lvalue
3330 attribute on or off on a Perl subroutine that is already defined
3331 does not always work properly. It may or may not do what you
3332 want, depending on what code is inside the subroutine, with exact
3333 details subject to change between Perl versions. Only do this
3334 if you really know what you are doing.
3336 =item lvalue attribute ignored after the subroutine has been defined
3338 (W misc) Using the C<:lvalue> declarative syntax to make a Perl
3339 subroutine an lvalue subroutine after it has been defined is
3340 not permitted. To make the subroutine an lvalue subroutine,
3341 add the lvalue attribute to the definition, or put the C<sub
3342 foo :lvalue;> declaration before the definition.
3344 See also L<attributes.pm|attributes>.
3346 =item Magical list constants are not supported
3348 (F) You assigned a magical array to a stash element, and then tried
3349 to use the subroutine from the same slot. You are asking Perl to do
3350 something it cannot do, details subject to change between Perl versions.
3352 =item Malformed integer in [] in pack
3354 (F) Between the brackets enclosing a numeric repeat count only digits
3355 are permitted. See L<perlfunc/pack>.
3357 =item Malformed integer in [] in unpack
3359 (F) Between the brackets enclosing a numeric repeat count only digits
3360 are permitted. See L<perlfunc/pack>.
3362 =item Malformed PERLLIB_PREFIX
3364 (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
3371 with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
3372 a builtin library search path, prefix2 is substituted. The error may
3373 appear if components are not found, or are too long. See
3374 "PERLLIB_PREFIX" in L<perlos2>.
3376 =item Malformed prototype for %s: %s
3378 (F) You tried to use a function with a malformed prototype. The
3379 syntax of function prototypes is given a brief compile-time check for
3380 obvious errors like invalid characters. A more rigorous check is run
3381 when the function is called.
3382 Perhaps the function's author was trying to write a subroutine signature
3383 but didn't enable that feature first (C<use feature 'signatures'>),
3384 so the signature was instead interpreted as a bad prototype.
3386 =item Malformed UTF-8 character%s
3388 (S utf8)(F) Perl detected a string that should be UTF-8, but didn't
3389 comply with UTF-8 encoding rules, or represents a code point whose
3390 ordinal integer value doesn't fit into the word size of the current
3391 platform (overflows). Details as to the exact malformation are given in
3392 the variable, C<%s>, part of the message.
3394 One possible cause is that you set the UTF8 flag yourself for data that
3395 you thought to be in UTF-8 but it wasn't (it was for example legacy
3396 8-bit data). To guard against this, you can use C<Encode::decode('UTF-8', ...)>.
3398 If you use the C<:encoding(UTF-8)> PerlIO layer for input, invalid byte
3399 sequences are handled gracefully, but if you use C<:utf8>, the flag is
3400 set without validating the data, possibly resulting in this error
3403 See also L<Encode/"Handling Malformed Data">.
3405 =item Malformed UTF-8 returned by \N{%s} immediately after '%s'
3407 (F) The charnames handler returned malformed UTF-8.
3409 =item Malformed UTF-8 string in '%c' format in unpack
3411 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3412 rules and perl was unable to guess how to make more progress.
3414 =item Malformed UTF-8 string in pack
3416 (F) You tried to pack something that didn't comply with UTF-8 encoding
3417 rules and perl was unable to guess how to make more progress.
3419 =item Malformed UTF-8 string in unpack
3421 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3422 rules and perl was unable to guess how to make more progress.
3424 =item Malformed UTF-8 string in "%s"
3426 (F) This message indicates a bug either in the Perl core or in XS
3427 code. Such code was trying to find out if a character, allegedly
3428 stored internally encoded as UTF-8, was of a given type, such as
3429 being punctuation or a digit. But the character was not encoded
3430 in legal UTF-8. The C<%s> is replaced by a string that can be used
3431 by knowledgeable people to determine what the type being checked
3434 Passing malformed strings was deprecated in Perl 5.18, and
3435 became fatal in Perl 5.26.
3437 =item Malformed UTF-16 surrogate
3439 (F) Perl thought it was reading UTF-16 encoded character data but while
3440 doing it Perl met a malformed Unicode surrogate.
3442 =item Mandatory parameter follows optional parameter
3444 (F) In a subroutine signature, you wrote something like "$a = undef,
3445 $b", making an earlier parameter optional and a later one mandatory.
3446 Parameters are filled from left to right, so it's impossible for the
3447 caller to omit an earlier one and pass a later one. If you want to act
3448 as if the parameters are filled from right to left, declare the rightmost
3449 optional and then shuffle the parameters around in the subroutine's body.
3451 =item Matched non-Unicode code point 0x%X against Unicode property; may
3454 (S non_unicode) Perl allows strings to contain a superset of
3455 Unicode code points; each code point may be as large as what is storable
3456 in an unsigned integer on your system, but these may not be accepted by
3457 other languages/systems. This message occurs when you matched a string
3458 containing such a code point against a regular expression pattern, and
3459 the code point was matched against a Unicode property, C<\p{...}> or
3460 C<\P{...}>. Unicode properties are only defined on Unicode code points,
3461 so the result of this match is undefined by Unicode, but Perl (starting
3462 in v5.20) treats non-Unicode code points as if they were typical
3463 unassigned Unicode ones, and matched this one accordingly. Whether a
3464 given property matches these code points or not is specified in
3465 L<perluniprops/Properties accessible through \p{} and \P{}>.
3467 This message is suppressed (unless it has been made fatal) if it is
3468 immaterial to the results of the match if the code point is Unicode or
3469 not. For example, the property C<\p{ASCII_Hex_Digit}> only can match
3470 the 22 characters C<[0-9A-Fa-f]>, so obviously all other code points,
3471 Unicode or not, won't match it. (And C<\P{ASCII_Hex_Digit}> will match
3472 every code point except these 22.)
3474 Getting this message indicates that the outcome of the match arguably
3475 should have been the opposite of what actually happened. If you think
3476 that is the case, you may wish to make the C<non_unicode> warnings
3477 category fatal; if you agree with Perl's decision, you may wish to turn
3480 See L<perlunicode/Beyond Unicode code points> for more information.
3482 =item %s matches null string many times in regex; marked by S<<-- HERE> in
3485 (W regexp) The pattern you've specified would be an infinite loop if the
3486 regular expression engine didn't specifically check for that. The S<<-- HERE>
3487 shows whereabouts in the regular expression the problem was discovered.
3490 =item Maximal count of pending signals (%u) exceeded
3492 (F) Perl aborted due to too high a number of signals pending. This
3493 usually indicates that your operating system tried to deliver signals
3494 too fast (with a very high priority), starving the perl process from
3495 resources it would need to reach a point where it can process signals
3496 safely. (See L<perlipc/"Deferred Signals (Safe Signals)">.)
3498 =item "%s" may clash with future reserved word
3500 (W) This warning may be due to running a perl5 script through a perl4
3501 interpreter, especially if the word that is being warned about is
3504 =item '%' may not be used in pack
3506 (F) You can't pack a string by supplying a checksum, because the
3507 checksumming process loses information, and you can't go the other way.
3508 See L<perlfunc/unpack>.
3510 =item Method for operation %s not found in package %s during blessing
3512 (F) An attempt was made to specify an entry in an overloading table that
3513 doesn't resolve to a valid subroutine. See L<overload>.
3515 =item Method %s not permitted
3517 See L</500 Server error>.
3519 =item Might be a runaway multi-line %s string starting on line %d
3521 (S) An advisory indicating that the previous error may have been caused
3522 by a missing delimiter on a string or pattern, because it eventually
3523 ended earlier on the current line.
3525 =item Misplaced _ in number
3527 (W syntax) An underscore (underbar) in a numeric constant did not
3528 separate two digits.
3530 =item Missing argument in %s
3532 (W missing) You called a function with fewer arguments than other
3533 arguments you supplied indicated would be needed.
3535 Currently only emitted when a printf-type format required more
3536 arguments than were supplied, but might be used in the future for
3537 other cases where we can statically determine that arguments to
3538 functions are missing, e.g. for the L<perlfunc/pack> function.
3540 =item Missing argument to -%c
3542 (F) The argument to the indicated command line switch must follow
3543 immediately after the switch, without intervening spaces.
3545 =item Missing braces on \N{}
3547 =item Missing braces on \N{} in regex; marked by S<<-- HERE> in m/%s/
3549 (F) Wrong syntax of character name literal C<\N{charname}> within
3550 double-quotish context. This can also happen when there is a space
3551 (or comment) between the C<\N> and the C<{> in a regex with the C</x> modifier.
3552 This modifier does not change the requirement that the brace immediately
3555 =item Missing braces on \o{}
3557 (F) A C<\o> must be followed immediately by a C<{> in double-quotish context.
3559 =item Missing comma after first argument to %s function
3561 (F) While certain functions allow you to specify a filehandle or an
3562 "indirect object" before the argument list, this ain't one of them.
3564 =item Missing command in piped open
3566 (W pipe) You used the C<open(FH, "| command")> or
3567 C<open(FH, "command |")> construction, but the command was missing or
3570 =item Missing control char name in \c
3572 (F) A double-quoted string ended with "\c", without the required control
3575 =item Missing ']' in prototype for %s : %s
3577 (W illegalproto) A grouping was started with C<[> but never closed with C<]>.
3579 =item Missing name in "%s sub"
3581 (F) The syntax for lexically scoped subroutines requires that
3582 they have a name with which they can be found.
3584 =item Missing $ on loop variable
3586 (F) Apparently you've been programming in B<csh> too much. Variables
3587 are always mentioned with the $ in Perl, unlike in the shells, where it
3588 can vary from one line to the next.
3590 =item (Missing operator before %s?)
3592 (S syntax) This is an educated guess made in conjunction with the message
3593 "%s found where operator expected". Often the missing operator is a comma.
3595 =item Missing or undefined argument to %s
3597 (F) You tried to call require or do with no argument or with an undefined
3598 value as an argument. Require expects either a package name or a
3599 file-specification as an argument; do expects a filename. See
3600 L<perlfunc/require EXPR> and L<perlfunc/do EXPR>.
3602 =item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
3604 (F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
3606 =item Missing right brace on \N{}
3608 =item Missing right brace on \N{} or unescaped left brace after \N
3610 (F) C<\N> has two meanings.
3612 The traditional one has it followed by a name enclosed in braces,
3613 meaning the character (or sequence of characters) given by that
3614 name. Thus C<\N{ASTERISK}> is another way of writing C<*>, valid in both
3615 double-quoted strings and regular expression patterns. In patterns,
3616 it doesn't have the meaning an unescaped C<*> does.
3618 Starting in Perl 5.12.0, C<\N> also can have an additional meaning (only)
3619 in patterns, namely to match a non-newline character. (This is short
3620 for C<[^\n]>, and like C<.> but is not affected by the C</s> regex modifier.)
3622 This can lead to some ambiguities. When C<\N> is not followed immediately
3623 by a left brace, Perl assumes the C<[^\n]> meaning. Also, if the braces
3624 form a valid quantifier such as C<\N{3}> or C<\N{5,}>, Perl assumes that this
3625 means to match the given quantity of non-newlines (in these examples,
3626 3; and 5 or more, respectively). In all other case, where there is a
3627 C<\N{> and a matching C<}>, Perl assumes that a character name is desired.
3629 However, if there is no matching C<}>, Perl doesn't know if it was
3630 mistakenly omitted, or if C<[^\n]{> was desired, and raises this error.
3631 If you meant the former, add the right brace; if you meant the latter,
3632 escape the brace with a backslash, like so: C<\N\{>
3634 =item Missing right curly or square bracket
3636 (F) The lexer counted more opening curly or square brackets than closing
3637 ones. As a general rule, you'll find it's missing near the place you
3640 =item (Missing semicolon on previous line?)
3642 (S syntax) This is an educated guess made in conjunction with the message
3643 "%s found where operator expected". Don't automatically put a semicolon on
3644 the previous line just because you saw this message.
3646 =item Modification of a read-only value attempted
3648 (F) You tried, directly or indirectly, to change the value of a
3649 constant. You didn't, of course, try "2 = 1", because the compiler
3650 catches that. But an easy way to do the same thing is:
3652 sub mod { $_[0] = 1 }
3655 Another way is to assign to a substr() that's off the end of the string.
3657 Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
3658 is aliased to a constant in the look I<LIST>:
3661 foreach my $n ($x, 2) {
3662 $n *= 2; # modifies the $x, but fails on attempt to
3665 =item Modification of non-creatable array value attempted, %s
3667 (F) You tried to make an array value spring into existence, and the
3668 subscript was probably negative, even counting from end of the array
3671 =item Modification of non-creatable hash value attempted, %s
3673 (P) You tried to make a hash value spring into existence, and it
3674 couldn't be created for some peculiar reason.
3676 =item Module name must be constant
3678 (F) Only a bare module name is allowed as the first argument to a "use".
3680 =item Module name required with -%c option
3682 (F) The C<-M> or C<-m> options say that Perl should load some module, but
3683 you omitted the name of the module. Consult L<perlrun> for full details
3684 about C<-M> and C<-m>.
3686 =item More than one argument to '%s' open
3688 (F) The C<open> function has been asked to open multiple files. This
3689 can happen if you are trying to open a pipe to a command that takes a
3690 list of arguments, but have forgotten to specify a piped open mode.
3691 See L<perlfunc/open> for details.
3693 =item mprotect for COW string %p %u failed with %d
3695 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3696 L<perlguts/"Copy on Write">), but a shared string buffer
3697 could not be made read-only.
3699 =item mprotect for %p %u failed with %d
3701 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see L<perlhacktips>),
3702 but an op tree could not be made read-only.
3704 =item mprotect RW for COW string %p %u failed with %d
3706 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3707 L<perlguts/"Copy on Write">), but a read-only shared string
3708 buffer could not be made mutable.
3710 =item mprotect RW for %p %u failed with %d
3712 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see
3713 L<perlhacktips>), but a read-only op tree could not be made
3714 mutable before freeing the ops.
3716 =item msg%s not implemented
3718 (F) You don't have System V message IPC on your system.
3720 =item Multidimensional syntax %s not supported
3722 (W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
3723 They're written like C<$foo[1][2][3]>, as in C.
3725 =item Multiple slurpy parameters not allowed
3727 (F) In subroutine signatures, a slurpy parameter (C<@> or C<%>) must be
3728 the last parameter, and there must not be more than one of them; for
3731 sub foo ($a, @b) {} # legal
3732 sub foo ($a, @b, %) {} # invalid
3734 =item '/' must follow a numeric type in unpack
3736 (F) You had an unpack template that contained a '/', but this did not
3737 follow some unpack specification producing a numeric value.
3738 See L<perlfunc/pack>.
3740 =item %s must not be a named sequence in transliteration operator
3742 (F) Transliteration (C<tr///> and C<y///>) transliterates individual
3743 characters. But a named sequence by definition is more than an
3744 individual charater, and hence doing this operation on it doesn't make
3747 =item "my sub" not yet implemented
3749 (F) Lexically scoped subroutines are not yet implemented. Don't try
3752 =item "my" subroutine %s can't be in a package
3754 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
3755 sense to try to declare one with a package qualifier on the front.
3757 =item "my %s" used in sort comparison
3759 (W syntax) The package variables $a and $b are used for sort comparisons.
3760 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
3761 sort comparison block, and the variable had earlier been declared as a
3762 lexical variable. Either qualify the sort variable with the package
3763 name, or rename the lexical variable.
3765 =item "my" variable %s can't be in a package
3767 (F) Lexically scoped variables aren't in a package, so it doesn't make
3768 sense to try to declare one with a package qualifier on the front. Use
3769 local() if you want to localize a package variable.
3771 =item Name "%s::%s" used only once: possible typo
3773 (W once) Typographical errors often show up as unique variable
3774 names. If you had a good reason for having a unique name, then
3775 just mention it again somehow to suppress the message. The C<our>
3776 declaration is also provided for this purpose.
3778 NOTE: This warning detects package symbols that have been used
3779 only once. This means lexical variables will never trigger this
3780 warning. It also means that all of the package variables $c, @c,
3781 %c, as well as *c, &c, sub c{}, c(), and c (the filehandle or
3782 format) are considered the same; if a program uses $c only once
3783 but also uses any of the others it will not trigger this warning.
3784 Symbols beginning with an underscore and symbols using special
3785 identifiers (q.v. L<perldata>) are exempt from this warning.
3787 =item Need exactly 3 octal digits in regex; marked by S<<-- HERE> in m/%s/
3789 (F) Within S<C<(?[ ])>>, all constants interpreted as octal need to be
3790 exactly 3 digits long. This helps catch some ambiguities. If your
3791 constant is too short, add leading zeros, like
3793 (?[ [ \078 ] ]) # Syntax error!
3794 (?[ [ \0078 ] ]) # Works
3795 (?[ [ \007 8 ] ]) # Clearer
3797 The maximum number this construct can express is C<\777>. If you
3798 need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes> instead. If you meant
3799 two separate things, you need to separate them:
3801 (?[ [ \7776 ] ]) # Syntax error!
3802 (?[ [ \o{7776} ] ]) # One meaning
3803 (?[ [ \777 6 ] ]) # Another meaning
3804 (?[ [ \777 \006 ] ]) # Still another
3806 =item Negative '/' count in unpack
3808 (F) The length count obtained from a length/code unpack operation was
3809 negative. See L<perlfunc/pack>.
3811 =item Negative length
3813 (F) You tried to do a read/write/send/recv operation with a buffer
3814 length that is less than 0. This is difficult to imagine.
3816 =item Negative offset to vec in lvalue context
3818 (F) When C<vec> is called in an lvalue context, the second argument must be
3819 greater than or equal to zero.
3821 =item Negative repeat count does nothing
3823 (W numeric) You tried to execute the
3824 L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
3825 times, which doesn't make sense.
3827 =item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
3829 (F) You can't quantify a quantifier without intervening parentheses.
3830 So things like ** or +* or ?* are illegal. The S<<-- HERE> shows
3831 whereabouts in the regular expression the problem was discovered.
3833 Note that the minimal matching quantifiers, C<*?>, C<+?>, and
3834 C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
3836 =item %s never introduced
3838 (S internal) The symbol in question was declared but somehow went out of
3839 scope before it could possibly have been used.
3841 =item next::method/next::can/maybe::next::method cannot find enclosing method
3843 (F) C<next::method> needs to be called within the context of a
3844 real method in a real package, and it could not find such a context.
3847 =item \N in a character class must be a named character: \N{...} in regex;
3848 marked by S<<-- HERE> in m/%s/
3850 (F) The new (as of Perl 5.12) meaning of C<\N> as C<[^\n]> is not valid in a
3851 bracketed character class, for the same reason that C<.> in a character
3852 class loses its specialness: it matches almost everything, which is
3853 probably not what you want.
3855 =item \N{} in inverted character class or as a range end-point is restricted to one character in regex; marked by <-- HERE in m/%s/
3857 (F) Named Unicode character escapes (C<\N{...}>) may return a
3858 multi-character sequence. Even though a character class is
3859 supposed to match just one character of input, perl will match the
3860 whole thing correctly, except when the class is inverted (C<[^...]>),
3861 or the escape is the beginning or final end point of a range. The
3862 mathematically logical behavior for what matches when inverting
3863 is very different from what people expect, so we have decided to
3864 forbid it. Similarly unclear is what should be generated when the
3865 C<\N{...}> is used as one of the end points of the range, such as in
3867 [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]
3869 What is meant here is unclear, as the C<\N{...}> escape is a sequence
3870 of code points, so this is made an error.
3872 =item \N{NAME} must be resolved by the lexer in regex; marked by
3873 S<<-- HERE> in m/%s/
3875 (F) When compiling a regex pattern, an unresolved named character or
3876 sequence was encountered. This can happen in any of several ways that
3877 bypass the lexer, such as using single-quotish context, or an extra
3878 backslash in double-quotish:
3880 $re = '\N{SPACE}'; # Wrong!
3881 $re = "\\N{SPACE}"; # Wrong!
3884 Instead, use double-quotes with a single backslash:
3886 $re = "\N{SPACE}"; # ok
3889 The lexer can be bypassed as well by creating the pattern from smaller
3893 /${re}{SPACE}/; # Wrong!
3895 It's not a good idea to split a construct in the middle like this, and
3896 it doesn't work here. Instead use the solution above.
3898 Finally, the message also can happen under the C</x> regex modifier when the
3899 C<\N> is separated by spaces from the C<{>, in which case, remove the spaces.
3901 /\N {SPACE}/x; # Wrong!
3904 =item No %s allowed while running setuid
3906 (F) Certain operations are deemed to be too insecure for a setuid or
3907 setgid script to even be allowed to attempt. Generally speaking there
3908 will be another way to do what you want that is, if not secure, at least
3909 securable. See L<perlsec>.
3911 =item No code specified for -%c
3913 (F) Perl's B<-e> and B<-E> command-line options require an argument. If
3914 you want to run an empty program, pass the empty string as a separate
3915 argument or run a program consisting of a single 0 or 1:
3921 =item No comma allowed after %s
3923 (F) A list operator that has a filehandle or "indirect object" is
3924 not allowed to have a comma between that and the following arguments.
3925 Otherwise it'd be just another one of the arguments.
3927 One possible cause for this is that you expected to have imported
3928 a constant to your name space with B<use> or B<import> while no such
3929 importing took place, it may for example be that your operating
3930 system does not support that particular constant. Hopefully you did
3931 use an explicit import list for the constants you expect to see;
3932 please see L<perlfunc/use> and L<perlfunc/import>. While an
3933 explicit import list would probably have caught this error earlier
3934 it naturally does not remedy the fact that your operating system
3935 still does not support that constant. Maybe you have a typo in
3936 the constants of the symbol import list of B<use> or B<import> or in the
3937 constant name at the line where this error was triggered?
3939 =item No command into which to pipe on command line
3941 (F) An error peculiar to VMS. Perl handles its own command line
3942 redirection, and found a '|' at the end of the command line, so it
3943 doesn't know where you want to pipe the output from this command.
3945 =item No DB::DB routine defined
3947 (F) The currently executing code was compiled with the B<-d> switch, but
3948 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3949 module) didn't define a routine to be called at the beginning of each
3952 =item No dbm on this machine
3954 (P) This is counted as an internal error, because every machine should
3955 supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
3957 =item No DB::sub routine defined
3959 (F) The currently executing code was compiled with the B<-d> switch, but
3960 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3961 module) didn't define a C<DB::sub> routine to be called at the beginning
3962 of each ordinary subroutine call.
3964 =item No directory specified for -I
3966 (F) The B<-I> command-line switch requires a directory name as part of the
3967 I<same> argument. Use B<-Ilib>, for instance. B<-I lib> won't work.
3969 =item No error file after 2> or 2>> on command line
3971 (F) An error peculiar to VMS. Perl handles its own command line
3972 redirection, and found a '2>' or a '2>>' on the command line, but can't
3973 find the name of the file to which to write data destined for stderr.
3975 =item No group ending character '%c' found in template
3977 (F) A pack or unpack template has an opening '(' or '[' without its
3978 matching counterpart. See L<perlfunc/pack>.
3980 =item No input file after < on command line
3982 (F) An error peculiar to VMS. Perl handles its own command line
3983 redirection, and found a '<' on the command line, but can't find the
3984 name of the file from which to read data for stdin.
3986 =item No next::method '%s' found for %s
3988 (F) C<next::method> found no further instances of this method name
3989 in the remaining packages of the MRO of this class. If you don't want
3990 it throwing an exception, use C<maybe::next::method>
3991 or C<next::can>. See L<mro>.
3993 =item Non-finite repeat count does nothing
3995 (W numeric) You tried to execute the
3996 L<C<x>|perlop/Multiplicative Operators> repetition operator C<Inf> (or
3997 C<-Inf>) or C<NaN> times, which doesn't make sense.
3999 =item Non-hex character in regex; marked by S<<-- HERE> in m/%s/
4001 (F) In a regular expression, there was a non-hexadecimal character where
4002 a hex one was expected, like
4007 =item Non-octal character in regex; marked by S<<-- HERE> in m/%s/
4009 (F) In a regular expression, there was a non-octal character where
4010 an octal one was expected, like
4014 =item Non-octal character '%c'. Resolved as "%s"
4016 (W digit) In parsing an octal numeric constant, a character was
4017 unexpectedly encountered that isn't octal. The resulting value
4020 =item "no" not allowed in expression
4022 (F) The "no" keyword is recognized and executed at compile time, and
4023 returns no useful value. See L<perlmod>.
4025 =item Non-string passed as bitmask
4027 (W misc) A number has been passed as a bitmask argument to select().
4028 Use the vec() function to construct the file descriptor bitmasks for
4029 select. See L<perlfunc/select>.
4031 =item No output file after > on command line
4033 (F) An error peculiar to VMS. Perl handles its own command line
4034 redirection, and found a lone '>' at the end of the command line, so it
4035 doesn't know where you wanted to redirect stdout.
4037 =item No output file after > or >> on command line
4039 (F) An error peculiar to VMS. Perl handles its own command line
4040 redirection, and found a '>' or a '>>' on the command line, but can't
4041 find the name of the file to which to write data destined for stdout.
4043 =item No package name allowed for variable %s in "our"
4045 (F) Fully qualified variable names are not allowed in "our"
4046 declarations, because that doesn't make much sense under existing
4047 rules. Such syntax is reserved for future extensions.
4049 =item No Perl script found in input
4051 (F) You called C<perl -x>, but no line was found in the file beginning
4052 with #! and containing the word "perl".
4054 =item No setregid available
4056 (F) Configure didn't find anything resembling the setregid() call for
4059 =item No setreuid available
4061 (F) Configure didn't find anything resembling the setreuid() call for
4064 =item No such class %s
4066 (F) You provided a class qualifier in a "my", "our" or "state"
4067 declaration, but this class doesn't exist at this point in your program.
4069 =item No such class field "%s" in variable %s of type %s
4071 (F) You tried to access a key from a hash through the indicated typed
4072 variable but that key is not allowed by the package of the same type.
4073 The indicated package has restricted the set of allowed keys using the
4076 =item No such hook: %s
4078 (F) You specified a signal hook that was not recognized by Perl.
4079 Currently, Perl accepts C<__DIE__> and C<__WARN__> as valid signal hooks.
4081 =item No such pipe open
4083 (P) An error peculiar to VMS. The internal routine my_pclose() tried to
4084 close a pipe which hadn't been opened. This should have been caught
4085 earlier as an attempt to close an unopened filehandle.
4087 =item No such signal: SIG%s
4089 (W signal) You specified a signal name as a subscript to %SIG that was
4090 not recognized. Say C<kill -l> in your shell to see the valid signal
4091 names on your system.
4093 =item Not a CODE reference
4095 (F) Perl was trying to evaluate a reference to a code value (that is, a
4096 subroutine), but found a reference to something else instead. You can
4097 use the ref() function to find out what kind of ref it really was. See
4100 =item Not a GLOB reference
4102 (F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
4103 symbol table entry that looks like C<*foo>), but found a reference to
4104 something else instead. You can use the ref() function to find out what
4105 kind of ref it really was. See L<perlref>.
4107 =item Not a HASH reference
4109 (F) Perl was trying to evaluate a reference to a hash value, but found a
4110 reference to something else instead. You can use the ref() function to
4111 find out what kind of ref it really was. See L<perlref>.
4113 =item '#' not allowed immediately following a sigil in a subroutine signature
4115 (F) In a subroutine signature definition, a comment following a sigil
4116 (C<$>, C<@> or C<%>), needs to be separated by whitespace or a commma etc., in
4117 particular to avoid confusion with the C<$#> variable. For example:
4120 sub f ($# ignore first arg
4123 sub f ($, # ignore first arg
4126 =item Not an ARRAY reference
4128 (F) Perl was trying to evaluate a reference to an array value, but found
4129 a reference to something else instead. You can use the ref() function
4130 to find out what kind of ref it really was. See L<perlref>.
4132 =item Not a SCALAR reference
4134 (F) Perl was trying to evaluate a reference to a scalar value, but found
4135 a reference to something else instead. You can use the ref() function
4136 to find out what kind of ref it really was. See L<perlref>.
4138 =item Not a subroutine reference
4140 (F) Perl was trying to evaluate a reference to a code value (that is, a
4141 subroutine), but found a reference to something else instead. You can
4142 use the ref() function to find out what kind of ref it really was. See
4145 =item Not a subroutine reference in overload table
4147 (F) An attempt was made to specify an entry in an overloading table that
4148 doesn't somehow point to a valid subroutine. See L<overload>.
4150 =item Not enough arguments for %s
4152 (F) The function requires more arguments than you specified.
4154 =item Not enough format arguments
4156 (W syntax) A format specified more picture fields than the next line
4157 supplied. See L<perlform>.
4161 (A) You've accidentally run your script through the Bourne shell instead
4162 of Perl. Check the #! line, or manually feed your script into Perl
4165 =item (?[...]) not valid in locale in regex; marked by S<<-- HERE> in m/%s/
4167 (F) C<(?[...])> cannot be used within the scope of a C<S<use locale>> or with
4168 an C</l> regular expression modifier, as that would require deferring
4169 to run-time the calculation of what it should evaluate to, and it is
4170 regex compile-time only.
4172 =item no UTC offset information; assuming local time is UTC
4174 (S) A warning peculiar to VMS. Perl was unable to find the local
4175 timezone offset, so it's assuming that local system time is equivalent
4176 to UTC. If it's not, define the logical name
4177 F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
4178 need to be added to UTC to get local time.
4180 =item NULL OP IN RUN
4182 (S debugging) Some internal routine called run() with a null opcode
4185 =item Null picture in formline
4187 (F) The first argument to formline must be a valid format picture
4188 specification. It was found to be empty, which probably means you
4189 supplied it an uninitialized value. See L<perlform>.
4193 (P) An attempt was made to realloc NULL.
4195 =item NULL regexp argument
4197 (P) The internal pattern matching routines blew it big time.
4199 =item NULL regexp parameter
4201 (P) The internal pattern matching routines are out of their gourd.
4203 =item Number too long
4205 (F) Perl limits the representation of decimal numbers in programs to
4206 about 250 characters. You've exceeded that length. Future
4207 versions of Perl are likely to eliminate this arbitrary limitation. In
4208 the meantime, try using scientific notation (e.g. "1e6" instead of
4211 =item Number with no digits
4213 (F) Perl was looking for a number but found nothing that looked like
4214 a number. This happens, for example with C<\o{}>, with no number between
4217 =item Octal number > 037777777777 non-portable
4219 (W portable) The octal number you specified is larger than 2**32-1
4220 (4294967295) and therefore non-portable between systems. See
4221 L<perlport> for more on portability concerns.
4223 =item Odd name/value argument for subroutine '%s'
4225 (F) A subroutine using a slurpy hash parameter in its signature
4226 received an odd number of arguments to populate the hash. It requires
4227 the arguments to be paired, with the same number of keys as values.
4228 The caller of the subroutine is presumably at fault.
4230 The message attempts to include the name of the called subroutine. If the
4231 subroutine has been aliased, the subroutine's original name will be shown,
4232 regardless of what name the caller used.
4234 =item Odd number of arguments for overload::constant
4236 (W overload) The call to overload::constant contained an odd number of
4237 arguments. The arguments should come in pairs.
4239 =item Odd number of elements in anonymous hash
4241 (W misc) You specified an odd number of elements to initialize a hash,
4242 which is odd, because hashes come in key/value pairs.
4244 =item Odd number of elements in hash assignment
4246 (W misc) You specified an odd number of elements to initialize a hash,
4247 which is odd, because hashes come in key/value pairs.
4249 =item Offset outside string
4251 (F)(W layer) You tried to do a read/write/send/recv/seek operation
4252 with an offset pointing outside the buffer. This is difficult to
4253 imagine. The sole exceptions to this are that zero padding will
4254 take place when going past the end of the string when either
4255 C<sysread()>ing a file, or when seeking past the end of a scalar opened
4256 for I/O (in anticipation of future reads and to imitate the behavior
4259 =item %s() on unopened %s
4261 (W unopened) An I/O operation was attempted on a filehandle that was
4262 never initialized. You need to do an open(), a sysopen(), or a socket()
4263 call, or call a constructor from the FileHandle package.
4265 =item -%s on unopened filehandle %s
4267 (W unopened) You tried to invoke a file test operator on a filehandle
4268 that isn't open. Check your control flow. See also L<perlfunc/-X>.
4272 (S internal) An internal warning that the grammar is screwed up.
4276 (S internal) An internal warning that the grammar is screwed up.
4278 =item Cannot open %s as a filehandle: it is already open as a dirhandle
4280 (F) You tried to use open() to associate a filehandle to
4281 a symbol (glob or scalar) that already holds a dirhandle.
4282 This idiom might render your code confusing
4283 and this was deprecated in Perl 5.10. As of Perl 5.28, this
4286 =item Cannot open %s as a dirhandle: it is already open as a filehandle
4288 (F) You tried to use opendir() to associate a dirhandle to
4289 a symbol (glob or scalar) that already holds a filehandle.
4290 This idiom might render your code confusing
4291 and this was deprecated in Perl 5.10. As of Perl 5.28, this
4294 =item Operand with no preceding operator in regex; marked by S<<-- HERE> in
4297 (F) You wrote something like
4299 (?[ \p{Digit} \p{Thai} ])
4301 There are two operands, but no operator giving how you want to combine
4304 =item Operation "%s": no method found, %s
4306 (F) An attempt was made to perform an overloaded operation for which no
4307 handler was defined. While some handlers can be autogenerated in terms
4308 of other handlers, there is no default handler for any operation, unless
4309 the C<fallback> overloading key is specified to be true. See L<overload>.
4311 =item Operation "%s" returns its argument for non-Unicode code point 0x%X
4313 (S non_unicode) You performed an operation requiring Unicode rules
4314 on a code point that is not in Unicode, so what it should do is not
4315 defined. Perl has chosen to have it do nothing, and warn you.
4317 If the operation shown is "ToFold", it means that case-insensitive
4318 matching in a regular expression was done on the code point.
4320 If you know what you are doing you can turn off this warning by
4321 C<no warnings 'non_unicode';>.
4323 =item Operation "%s" returns its argument for UTF-16 surrogate U+%X
4325 (S surrogate) You performed an operation requiring Unicode
4326 rules on a Unicode surrogate. Unicode frowns upon the use
4327 of surrogates for anything but storing strings in UTF-16, but
4328 rules are (reluctantly) defined for the surrogates, and
4329 they are to do nothing for this operation. Because the use of
4330 surrogates can be dangerous, Perl warns.
4332 If the operation shown is "ToFold", it means that case-insensitive
4333 matching in a regular expression was done on the code point.
4335 If you know what you are doing you can turn off this warning by
4336 C<no warnings 'surrogate';>.
4338 =item Operator or semicolon missing before %s
4340 (S ambiguous) You used a variable or subroutine call where the parser
4341 was expecting an operator. The parser has assumed you really meant to
4342 use an operator, but this is highly likely to be incorrect. For
4343 example, if you say "*foo *foo" it will be interpreted as if you said
4346 =item Optional parameter lacks default expression
4348 (F) In a subroutine signature, you wrote something like "$a =", making a
4349 named optional parameter without a default value. A nameless optional
4350 parameter is permitted to have no default value, but a named one must
4351 have a specific default. You probably want "$a = undef".
4353 =item "our" variable %s redeclared
4355 (W misc) You seem to have already declared the same global once before
4356 in the current lexical scope.
4358 =item Out of memory!
4360 (X) The malloc() function returned 0, indicating there was insufficient
4361 remaining memory (or virtual memory) to satisfy the request. Perl has
4362 no option but to exit immediately.
4364 At least in Unix you may be able to get past this by increasing your
4365 process datasize limits: in csh/tcsh use C<limit> and
4366 C<limit datasize n> (where C<n> is the number of kilobytes) to check
4367 the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
4368 and C<ulimit -d n>, respectively.
4370 =item Out of memory during %s extend
4372 (X) An attempt was made to extend an array, a list, or a string beyond
4373 the largest possible memory allocation.
4375 =item Out of memory during "large" request for %s
4377 (F) The malloc() function returned 0, indicating there was insufficient
4378 remaining memory (or virtual memory) to satisfy the request. However,
4379 the request was judged large enough (compile-time default is 64K), so a
4380 possibility to shut down by trapping this error is granted.
4382 =item Out of memory during request for %s
4384 (X)(F) The malloc() function returned 0, indicating there was
4385 insufficient remaining memory (or virtual memory) to satisfy the
4388 The request was judged to be small, so the possibility to trap it
4389 depends on the way perl was compiled. By default it is not trappable.
4390 However, if compiled for this, Perl may use the contents of C<$^M> as an
4391 emergency pool after die()ing with this message. In this case the error
4392 is trappable I<once>, and the error message will include the line and file
4393 where the failed request happened.
4395 =item Out of memory during ridiculously large request
4397 (F) You can't allocate more than 2^31+"small amount" bytes. This error
4398 is most likely to be caused by a typo in the Perl program. e.g.,
4399 C<$arr[time]> instead of C<$arr[$time]>.
4401 =item Out of memory for yacc stack
4403 (F) The yacc parser wanted to grow its stack so it could continue
4404 parsing, but realloc() wouldn't give it more memory, virtual or
4407 =item '.' outside of string in pack
4409 (F) The argument to a '.' in your template tried to move the working
4410 position to before the start of the packed string being built.
4412 =item '@' outside of string in unpack
4414 (F) You had a template that specified an absolute position outside
4415 the string being unpacked. See L<perlfunc/pack>.
4417 =item '@' outside of string with malformed UTF-8 in unpack
4419 (F) You had a template that specified an absolute position outside
4420 the string being unpacked. The string being unpacked was also invalid
4421 UTF-8. See L<perlfunc/pack>.
4423 =item overload arg '%s' is invalid
4425 (W overload) The L<overload> pragma was passed an argument it did not
4426 recognize. Did you mistype an operator?
4428 =item Overloaded dereference did not return a reference
4430 (F) An object with an overloaded dereference operator was dereferenced,
4431 but the overloaded operation did not return a reference. See
4434 =item Overloaded qr did not return a REGEXP
4436 (F) An object with a C<qr> overload was used as part of a match, but the
4437 overloaded operation didn't return a compiled regexp. See L<overload>.
4439 =item %s package attribute may clash with future reserved word: %s
4441 (W reserved) A lowercase attribute name was used that had a
4442 package-specific handler. That name might have a meaning to Perl itself
4443 some day, even though it doesn't yet. Perhaps you should use a
4444 mixed-case attribute name, instead. See L<attributes>.
4446 =item pack/unpack repeat count overflow
4448 (F) You can't specify a repeat count so large that it overflows your
4449 signed integers. See L<perlfunc/pack>.
4453 (W io) A single call to write() produced more lines than can fit on a
4454 page. See L<perlform>.
4458 (P) An internal error.
4460 =item panic: attempt to call %s in %s
4462 (P) One of the file test operators entered a code branch that calls
4463 an ACL related-function, but that function is not available on this
4464 platform. Earlier checks mean that it should not be possible to
4465 enter this branch on this platform.
4467 =item panic: child pseudo-process was never scheduled
4469 (P) A child pseudo-process in the ithreads implementation on Windows
4470 was not scheduled within the time period allowed and therefore was not
4471 able to initialize properly.
4473 =item panic: ck_grep, type=%u
4475 (P) Failed an internal consistency check trying to compile a grep.
4477 =item panic: corrupt saved stack index %ld
4479 (P) The savestack was requested to restore more localized values than
4480 there are in the savestack.
4482 =item panic: del_backref
4484 (P) Failed an internal consistency check while trying to reset a weak
4487 =item panic: do_subst
4489 (P) The internal pp_subst() routine was called with invalid operational
4492 =item panic: do_trans_%s
4494 (P) The internal do_trans routines were called with invalid operational
4497 =item panic: fold_constants JMPENV_PUSH returned %d
4499 (P) While attempting folding constants an exception other than an C<eval>
4502 =item panic: frexp: %f
4504 (P) The library function frexp() failed, making printf("%f") impossible.
4506 =item panic: goto, type=%u, ix=%ld
4508 (P) We popped the context stack to a context with the specified label,
4509 and then discovered it wasn't a context we know how to do a goto in.
4511 =item panic: gp_free failed to free glob pointer
4513 (P) The internal routine used to clear a typeglob's entries tried
4514 repeatedly, but each time something re-created entries in the glob.
4515 Most likely the glob contains an object with a reference back to
4516 the glob and a destructor that adds a new object to the glob.
4518 =item panic: INTERPCASEMOD, %s
4520 (P) The lexer got into a bad state at a case modifier.
4522 =item panic: INTERPCONCAT, %s
4524 (P) The lexer got into a bad state parsing a string with brackets.
4526 =item panic: kid popen errno read
4528 (F) A forked child returned an incomprehensible message about its errno.
4530 =item panic: last, type=%u
4532 (P) We popped the context stack to a block context, and then discovered
4533 it wasn't a block context.
4535 =item panic: leave_scope clearsv
4537 (P) A writable lexical variable became read-only somehow within the
4540 =item panic: leave_scope inconsistency %u
4542 (P) The savestack probably got out of sync. At least, there was an
4543 invalid enum on the top of it.
4545 =item panic: magic_killbackrefs
4547 (P) Failed an internal consistency check while trying to reset all weak
4548 references to an object.
4550 =item panic: malloc, %s
4552 (P) Something requested a negative number of bytes of malloc.
4554 =item panic: memory wrap
4556 (P) Something tried to allocate either more memory than possible or a
4559 =item panic: pad_alloc, %p!=%p
4561 (P) The compiler got confused about which scratch pad it was allocating
4562 and freeing temporaries and lexicals from.
4564 =item panic: pad_free curpad, %p!=%p
4566 (P) The compiler got confused about which scratch pad it was allocating
4567 and freeing temporaries and lexicals from.
4569 =item panic: pad_free po
4571 (P) A zero scratch pad offset was detected internally. An attempt was
4572 made to free a target that had not been allocated to begin with.
4574 =item panic: pad_reset curpad, %p!=%p
4576 (P) The compiler got confused about which scratch pad it was allocating
4577 and freeing temporaries and lexicals from.
4579 =item panic: pad_sv po
4581 (P) A zero scratch pad offset was detected internally. Most likely
4582 an operator needed a target but that target had not been allocated
4583 for whatever reason.
4585 =item panic: pad_swipe curpad, %p!=%p
4587 (P) The compiler got confused about which scratch pad it was allocating
4588 and freeing temporaries and lexicals from.
4590 =item panic: pad_swipe po
4592 (P) An invalid scratch pad offset was detected internally.
4594 =item panic: pp_iter, type=%u
4596 (P) The foreach iterator got called in a non-loop context frame.
4598 =item panic: pp_match%s
4600 (P) The internal pp_match() routine was called with invalid operational
4603 =item panic: realloc, %s
4605 (P) Something requested a negative number of bytes of realloc.
4607 =item panic: reference miscount on nsv in sv_replace() (%d != 1)
4609 (P) The internal sv_replace() function was handed a new SV with a
4610 reference count other than 1.
4612 =item panic: restartop in %s
4614 (P) Some internal routine requested a goto (or something like it), and
4615 didn't supply the destination.
4617 =item panic: return, type=%u
4619 (P) We popped the context stack to a subroutine or eval context, and
4620 then discovered it wasn't a subroutine or eval context.
4622 =item panic: scan_num, %s
4624 (P) scan_num() got called on something that wasn't a number.
4626 =item panic: Sequence (?{...}): no code block found in regex m/%s/
4628 (P) While compiling a pattern that has embedded (?{}) or (??{}) code
4629 blocks, perl couldn't locate the code block that should have already been
4630 seen and compiled by perl before control passed to the regex compiler.
4632 =item panic: strxfrm() gets absurd - a => %u, ab => %u
4634 (P) The interpreter's sanity check of the C function strxfrm() failed.
4635 In your current locale the returned transformation of the string "ab"
4636 is shorter than that of the string "a", which makes no sense.
4638 =item panic: sv_chop %s
4640 (P) The sv_chop() routine was passed a position that is not within the
4641 scalar's string buffer.
4643 =item panic: sv_insert, midend=%p, bigend=%p
4645 (P) The sv_insert() routine was told to remove more string than there
4648 =item panic: top_env
4650 (P) The compiler attempted to do a goto, or something weird like that.
4652 =item panic: unimplemented op %s (#%d) called
4654 (P) The compiler is screwed up and attempted to use an op that isn't
4655 permitted at run time.
4657 =item panic: unknown OA_*: %x
4659 (P) The internal routine that handles arguments to C<&CORE::foo()>
4660 subroutine calls was unable to determine what type of arguments
4663 =item panic: utf16_to_utf8: odd bytelen
4665 (P) Something tried to call utf16_to_utf8 with an odd (as opposed
4666 to even) byte length.
4668 =item panic: utf16_to_utf8_reversed: odd bytelen
4670 (P) Something tried to call utf16_to_utf8_reversed with an odd (as opposed
4671 to even) byte length.
4673 =item panic: yylex, %s
4675 (P) The lexer got into a bad state while processing a case modifier.
4677 =item Parentheses missing around "%s" list
4679 (W parenthesis) You said something like
4685 my ($foo, $bar) = @_;
4687 Remember that "my", "our", "local" and "state" bind tighter than comma.
4689 =item Parsing code internal error (%s)
4691 (F) Parsing code supplied by an extension violated the parser's API in
4694 =item Pattern subroutine nesting without pos change exceeded limit in regex
4696 (F) You used a pattern that uses too many nested subpattern calls without
4697 consuming any text. Restructure the pattern so text is consumed before
4698 the nesting limit is exceeded.
4700 =item C<-p> destination: %s
4702 (F) An error occurred during the implicit output invoked by the C<-p>
4703 command-line switch. (This output goes to STDOUT unless you've
4704 redirected it with select().)
4706 =item Perl API version %s of %s does not match %s
4708 (F) The XS module in question was compiled against a different incompatible
4709 version of Perl than the one that has loaded the XS module.
4711 =item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
4712 utility to report; in regex; marked by S<<-- HERE> in m/%s/
4714 (S regexp) You used a regular expression with case-insensitive matching,
4715 and there is a bug in Perl in which the built-in regular expression
4716 folding rules are not accurate. This may lead to incorrect results.
4717 Please report this as a bug using the L<perlbug> utility.
4719 =item PerlIO layer ':win32' is experimental
4721 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
4722 experimental. If you want to take the risk of using this layer,
4723 simply disable this warning:
4725 no warnings "experimental::win32_perlio";
4727 =item Perl_my_%s() not available
4729 (F) Your platform has very uncommon byte-order and integer size,
4730 so it was not possible to set up some or all fixed-width byte-order
4731 conversion functions. This is only a problem when you're using the
4732 '<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
4734 =item Perl %s required (did you mean %s?)--this is only %s, stopped
4736 (F) The code you are trying to run has asked for a newer version of
4737 Perl than you are running. Perhaps C<use 5.10> was written instead
4738 of C<use 5.010> or C<use v5.10>. Without the leading C<v>, the number is
4739 interpreted as a decimal, with every three digits after the
4740 decimal point representing a part of the version number. So 5.10
4741 is equivalent to v5.100.
4743 =item Perl %s required--this is only %s, stopped
4745 (F) The module in question uses features of a version of Perl more
4746 recent than the currently running version. How long has it been since
4747 you upgraded, anyway? See L<perlfunc/require>.
4749 =item PERL_SH_DIR too long
4751 (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
4752 C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
4754 =item PERL_SIGNALS illegal: "%s"
4756 (X) See L<perlrun/PERL_SIGNALS> for legal values.
4758 =item Perls since %s too modern--this is %s, stopped
4760 (F) The code you are trying to run claims it will not run
4761 on the version of Perl you are using because it is too new.
4762 Maybe the code needs to be updated, or maybe it is simply
4763 wrong and the version check should just be removed.
4765 =item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only partially set
4767 (S) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
4768 contained a non hex character. This could mean you are not using the
4769 hash seed you think you are.
4771 =item perl: warning: Setting locale failed.
4773 (S) The whole warning message will look something like:
4775 perl: warning: Setting locale failed.
4776 perl: warning: Please check that your locale settings:
4779 are supported and installed on your system.
4780 perl: warning: Falling back to the standard locale ("C").
4782 Exactly what were the failed locale settings varies. In the above the
4783 settings were that the LC_ALL was "En_US" and the LANG had no value.
4784 This error means that Perl detected that you and/or your operating
4785 system supplier and/or system administrator have set up the so-called
4786 locale system but Perl could not use those settings. This was not
4787 dead serious, fortunately: there is a "default locale" called "C" that
4788 Perl can and will use, and the script will be run. Before you really
4789 fix the problem, however, you will get the same error message each
4790 time you run Perl. How to really fix the problem can be found in
4791 L<perllocale> section B<LOCALE PROBLEMS>.
4793 =item perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
4795 (S) Perl was run with the environment variable PERL_PERTURB_KEYS defined
4796 but containing an unexpected value. The legal values of this setting
4799 Numeric | String | Result
4800 --------+---------------+-----------------------------------------
4801 0 | NO | Disables key traversal randomization
4802 1 | RANDOM | Enables full key traversal randomization
4803 2 | DETERMINISTIC | Enables repeatable key traversal
4806 Both numeric and string values are accepted, but note that string values are
4807 case sensitive. The default for this setting is "RANDOM" or 1.
4809 =item pid %x not a child
4811 (W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
4812 process which isn't a subprocess of the current process. While this is
4813 fine from VMS' perspective, it's probably not what you intended.
4815 =item 'P' must have an explicit size in unpack
4817 (F) The unpack format P must have an explicit size, not "*".
4819 =item POSIX class [:%s:] unknown in regex; marked by S<<-- HERE> in m/%s/
4821 (F) The class in the character class [: :] syntax is unknown. The S<<-- HERE>
4822 shows whereabouts in the regular expression the problem was discovered.
4823 Note that the POSIX character classes do B<not> have the C<is> prefix
4824 the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
4825 not C<isprint>. See L<perlre>.
4827 =item POSIX getpgrp can't take an argument
4829 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
4830 the BSD version, which takes a pid.
4832 =item POSIX syntax [%c %c] belongs inside character classes%s in regex; marked by
4833 S<<-- HERE> in m/%s/
4835 (W regexp) Perl thinks that you intended to write a POSIX character
4836 class, but didn't use enough brackets. These POSIX class constructs [:
4837 :], [= =], and [. .] go I<inside> character classes, the [] are part of
4838 the construct, for example: C<qr/[012[:alpha:]345]/>. What the regular
4839 expression pattern compiled to is probably not what you were intending.
4840 For example, C<qr/[:alpha:]/> compiles to a regular bracketed character
4841 class consisting of the four characters C<":">, C<"a">, C<"l">,
4842 C<"h">, and C<"p">. To specify the POSIX class, it should have been
4843 written C<qr/[[:alpha:]]/>.
4845 Note that [= =] and [. .] are not currently
4846 implemented; they are simply placeholders for future extensions and
4847 will cause fatal errors. The S<<-- HERE> shows whereabouts in the regular
4848 expression the problem was discovered. See L<perlre>.
4850 If the specification of the class was not completely valid, the message
4853 =item POSIX syntax [. .] is reserved for future extensions in regex; marked by
4854 S<<-- HERE> in m/%s/
4856 (F) Within regular expression character classes ([]) the syntax beginning
4857 with "[." and ending with ".]" is reserved for future extensions. If you
4858 need to represent those character sequences inside a regular expression
4859 character class, just quote the square brackets with the backslash: "\[."
4860 and ".\]". The S<<-- HERE> shows whereabouts in the regular expression the
4861 problem was discovered. See L<perlre>.
4863 =item POSIX syntax [= =] is reserved for future extensions in regex; marked by
4864 S<<-- HERE> in m/%s/
4866 (F) Within regular expression character classes ([]) the syntax beginning
4867 with "[=" and ending with "=]" is reserved for future extensions. If you
4868 need to represent those character sequences inside a regular expression
4869 character class, just quote the square brackets with the backslash: "\[="
4870 and "=\]". The S<<-- HERE> shows whereabouts in the regular expression the
4871 problem was discovered. See L<perlre>.
4873 =item Possible attempt to put comments in qw() list
4875 (W qw) qw() lists contain items separated by whitespace; as with literal
4876 strings, comment characters are not ignored, but are instead treated as
4877 literal data. (You may have used different delimiters than the
4878 parentheses shown here; braces are also frequently used.)
4880 You probably wrote something like this:
4887 when you should have written this:
4894 If you really want comments, build your list the
4895 old-fashioned way, with quotes and commas:
4899 'b', # another comment
4902 =item Possible attempt to separate words with commas
4904 (W qw) qw() lists contain items separated by whitespace; therefore
4905 commas aren't needed to separate the items. (You may have used
4906 different delimiters than the parentheses shown here; braces are also
4909 You probably wrote something like this:
4913 which puts literal commas into some of the list items. Write it without
4914 commas if you don't want them to appear in your data:
4918 =item Possible memory corruption: %s overflowed 3rd argument
4920 (F) An ioctl() or fcntl() returned more than Perl was bargaining for.
4921 Perl guesses a reasonable buffer size, but puts a sentinel byte at the
4922 end of the buffer just in case. This sentinel byte got clobbered, and
4923 Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
4925 =item Possible precedence issue with control flow operator
4927 (W syntax) There is a possible problem with the mixing of a control
4928 flow operator (e.g. C<return>) and a low-precedence operator like
4931 sub { return $a or $b; }
4935 sub { (return $a) or $b; }
4937 Which is effectively just:
4941 Either use parentheses or the high-precedence variant of the operator.
4943 Note this may be also triggered for constructs like:
4947 =item Possible precedence problem on bitwise %s operator
4949 (W precedence) Your program uses a bitwise logical operator in conjunction
4950 with a numeric comparison operator, like this :
4952 if ($x & $y == 0) { ... }
4954 This expression is actually equivalent to C<$x & ($y == 0)>, due to the
4955 higher precedence of C<==>. This is probably not what you want. (If you
4956 really meant to write this, disable the warning, or, better, put the
4957 parentheses explicitly and write C<$x & ($y == 0)>).
4959 =item Possible unintended interpolation of $\ in regex
4961 (W ambiguous) You said something like C<m/$\/> in a regex.
4962 The regex C<m/foo$\s+bar/m> translates to: match the word 'foo', the output
4963 record separator (see L<perlvar/$\>) and the letter 's' (one time or more)
4964 followed by the word 'bar'.
4966 If this is what you intended then you can silence the warning by using
4967 C<m/${\}/> (for example: C<m/foo${\}s+bar/>).
4969 If instead you intended to match the word 'foo' at the end of the line
4970 followed by whitespace and the word 'bar' on the next line then you can use
4971 C<m/$(?)\/> (for example: C<m/foo$(?)\s+bar/>).
4973 =item Possible unintended interpolation of %s in string
4975 (W ambiguous) You said something like '@foo' in a double-quoted string
4976 but there was no array C<@foo> in scope at the time. If you wanted a
4977 literal @foo, then write it as \@foo; otherwise find out what happened
4978 to the array you apparently lost track of.
4980 =item Precedence problem: open %s should be open(%s)
4982 (S precedence) The old irregular construct
4986 is now misinterpreted as
4990 because of the strict regularization of Perl 5's grammar into unary and
4991 list operators. (The old open was a little of both.) You must put
4992 parentheses around the filehandle, or use the new "or" operator instead
4995 =item Premature end of script headers
4997 See L</500 Server error>.
4999 =item printf() on closed filehandle %s
5001 (W closed) The filehandle you're writing to got itself closed sometime
5002 before now. Check your control flow.
5004 =item print() on closed filehandle %s
5006 (W closed) The filehandle you're printing on got itself closed sometime
5007 before now. Check your control flow.
5009 =item Process terminated by SIG%s
5011 (W) This is a standard message issued by OS/2 applications, while *nix
5012 applications die in silence. It is considered a feature of the OS/2
5013 port. One can easily disable this by appropriate sighandlers, see
5014 L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
5017 =item Prototype after '%c' for %s : %s
5019 (W illegalproto) A character follows % or @ in a prototype. This is
5020 useless, since % and @ gobble the rest of the subroutine arguments.
5022 =item Prototype mismatch: %s vs %s
5024 (S prototype) The subroutine being declared or defined had previously been
5025 declared or defined with a different function prototype.
5027 =item Prototype not terminated
5029 (F) You've omitted the closing parenthesis in a function prototype
5032 =item Prototype '%s' overridden by attribute 'prototype(%s)' in %s
5034 (W prototype) A prototype was declared in both the parentheses after
5035 the sub name and via the prototype attribute. The prototype in
5036 parentheses is useless, since it will be replaced by the prototype
5037 from the attribute before it's ever used.
5039 =item Quantifier follows nothing in regex; marked by S<<-- HERE> in m/%s/
5041 (F) You started a regular expression with a quantifier. Backslash it if
5042 you meant it literally. The S<<-- HERE> shows whereabouts in the regular
5043 expression the problem was discovered. See L<perlre>.
5045 =item Quantifier in {,} bigger than %d in regex; marked by S<<-- HERE> in m/%s/
5047 (F) There is currently a limit to the size of the min and max values of
5048 the {min,max} construct. The S<<-- HERE> shows whereabouts in the regular
5049 expression the problem was discovered. See L<perlre>.
5051 =item Quantifier {n,m} with n > m can't match in regex
5053 =item Quantifier {n,m} with n > m can't match in regex; marked by
5054 S<<-- HERE> in m/%s/
5056 (W regexp) Minima should be less than or equal to maxima. If you really
5057 want your regexp to match something 0 times, just put {0}.
5059 =item Quantifier unexpected on zero-length expression in regex m/%s/
5061 (W regexp) You applied a regular expression quantifier in a place where
5062 it makes no sense, such as on a zero-width assertion. Try putting the
5063 quantifier inside the assertion instead. For example, the way to match
5064 "abc" provided that it is followed by three repetitions of "xyz" is
5065 C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
5067 =item Range iterator outside integer range
5069 (F) One (or both) of the numeric arguments to the range operator ".."
5070 are outside the range which can be represented by integers internally.
5071 One possible workaround is to force Perl to use magical string increment
5072 by prepending "0" to your numbers.
5074 =item Ranges of ASCII printables should be some subset of "0-9", "A-Z", or
5075 "a-z" in regex; marked by S<<-- HERE> in m/%s/
5077 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
5079 Stricter rules help to find typos and other errors. Perhaps you didn't
5080 even intend a range here, if the C<"-"> was meant to be some other
5081 character, or should have been escaped (like C<"\-">). If you did
5082 intend a range, the one that was used is not portable between ASCII and
5083 EBCDIC platforms, and doesn't have an obvious meaning to a casual
5086 [3-7] # OK; Obvious and portable
5087 [d-g] # OK; Obvious and portable
5088 [A-Y] # OK; Obvious and portable
5089 [A-z] # WRONG; Not portable; not clear what is meant
5090 [a-Z] # WRONG; Not portable; not clear what is meant
5091 [%-.] # WRONG; Not portable; not clear what is meant
5092 [\x41-Z] # WRONG; Not portable; not obvious to non-geek
5094 (You can force portability by specifying a Unicode range, which means that
5095 the endpoints are specified by
5096 L<C<\N{...}>|perlrecharclass/Character Ranges>, but the meaning may
5097 still not be obvious.)
5098 The stricter rules require that ranges that start or stop with an ASCII
5099 character that is not a control have all their endpoints be the literal
5100 character, and not some escape sequence (like C<"\x41">), and the ranges
5101 must be all digits, or all uppercase letters, or all lowercase letters.
5103 =item Ranges of digits should be from the same group in regex; marked by
5104 S<<-- HERE> in m/%s/
5106 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
5108 Stricter rules help to find typos and other errors. You included a
5109 range, and at least one of the end points is a decimal digit. Under the
5110 stricter rules, when this happens, both end points should be digits in
5111 the same group of 10 consecutive digits.
5113 =item readdir() attempted on invalid dirhandle %s
5115 (W io) The dirhandle you're reading from is either closed or not really
5116 a dirhandle. Check your control flow.
5118 =item readline() on closed filehandle %s
5120 (W closed) The filehandle you're reading from got itself closed sometime
5121 before now. Check your control flow.
5123 =item read() on closed filehandle %s
5125 (W closed) You tried to read from a closed filehandle.
5127 =item read() on unopened filehandle %s
5129 (W unopened) You tried to read from a filehandle that was never opened.
5131 =item Reallocation too large: %x
5133 (F) You can't allocate more than 64K on an MS-DOS machine.
5135 =item realloc() of freed memory ignored
5137 (S malloc) An internal routine called realloc() on something that had
5140 =item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
5142 (S debugging) You can't use the B<-D> option unless the code to produce
5143 the desired output is compiled into Perl, which entails some overhead,
5144 which is why it's currently left out of your copy.
5146 =item Recursive call to Perl_load_module in PerlIO_find_layer
5148 (P) It is currently not permitted to load modules when creating
5149 a filehandle inside an %INC hook. This can happen with C<open my
5150 $fh, '<', \$scalar>, which implicitly loads PerlIO::scalar. Try
5151 loading PerlIO::scalar explicitly first.
5153 =item Recursive inheritance detected in package '%s'
5155 (F) While calculating the method resolution order (MRO) of a package, Perl
5156 believes it found an infinite loop in the C<@ISA> hierarchy. This is a
5157 crude check that bails out after 100 levels of C<@ISA> depth.
5159 =item Redundant argument in %s
5161 (W redundant) You called a function with more arguments than other
5162 arguments you supplied indicated would be needed. Currently only
5163 emitted when a printf-type format required fewer arguments than were
5164 supplied, but might be used in the future for e.g. L<perlfunc/pack>.
5166 =item refcnt_dec: fd %d%s
5168 =item refcnt: fd %d%s
5170 =item refcnt_inc: fd %d%s
5172 (P) Perl's I/O implementation failed an internal consistency check. If
5173 you see this message, something is very wrong.
5175 =item Reference found where even-sized list expected
5177 (W misc) You gave a single reference where Perl was expecting a list
5178 with an even number of elements (for assignment to a hash). This
5179 usually means that you used the anon hash constructor when you meant
5180 to use parens. In any case, a hash requires key/value B<pairs>.
5182 %hash = { one => 1, two => 2, }; # WRONG
5183 %hash = [ qw/ an anon array / ]; # WRONG
5184 %hash = ( one => 1, two => 2, ); # right
5185 %hash = qw( one 1 two 2 ); # also fine
5187 =item Reference is already weak
5189 (W misc) You have attempted to weaken a reference that is already weak.
5190 Doing so has no effect.
5192 =item Reference to invalid group 0 in regex; marked by S<<-- HERE> in m/%s/
5194 (F) You used C<\g0> or similar in a regular expression. You may refer
5195 to capturing parentheses only with strictly positive integers
5196 (normal backreferences) or with strictly negative integers (relative
5197 backreferences). Using 0 does not make sense.
5199 =item Reference to nonexistent group in regex; marked by S<<-- HERE> in
5202 (F) You used something like C<\7> in your regular expression, but there are
5203 not at least seven sets of capturing parentheses in the expression. If
5204 you wanted to have the character with ordinal 7 inserted into the regular
5205 expression, prepend zeroes to make it three digits long: C<\007>
5207 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5210 =item Reference to nonexistent named group in regex; marked by S<<-- HERE>
5213 (F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
5214 expression, but there is no corresponding named capturing parentheses
5215 such as C<(?'NAME'...)> or C<< (?<NAME>...) >>. Check if the name has been
5216 spelled correctly both in the backreference and the declaration.
5218 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5221 =item Reference to nonexistent or unclosed group in regex; marked by
5222 S<<-- HERE> in m/%s/
5224 (F) You used something like C<\g{-7}> in your regular expression, but there
5225 are not at least seven sets of closed capturing parentheses in the
5226 expression before where the C<\g{-7}> was located.
5228 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5231 =item regexp memory corruption
5233 (P) The regular expression engine got confused by what the regular
5234 expression compiler gave it.
5236 =item Regexp modifier "/%c" may appear a maximum of twice
5238 =item Regexp modifier "%c" may appear a maximum of twice in regex; marked
5239 by S<<-- HERE> in m/%s/
5241 (F) The regular expression pattern had too many occurrences
5242 of the specified modifier. Remove the extraneous ones.
5244 =item Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
5247 (F) Turning off the given modifier has the side effect of turning on
5248 another one. Perl currently doesn't allow this. Reword the regular
5249 expression to use the modifier you want to turn on (and place it before
5250 the minus), instead of the one you want to turn off.
5252 =item Regexp modifier "/%c" may not appear twice
5254 =item Regexp modifier "%c" may not appear twice in regex; marked by <--
5257 (F) The regular expression pattern had too many occurrences
5258 of the specified modifier. Remove the extraneous ones.
5260 =item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5262 =item Regexp modifiers "%c" and "%c" are mutually exclusive in regex;
5263 marked by S<<-- HERE> in m/%s/
5265 (F) The regular expression pattern had more than one of these
5266 mutually exclusive modifiers. Retain only the modifier that is
5267 supposed to be there.
5269 =item Regexp out of space in regex m/%s/
5271 (P) A "can't happen" error, because safemalloc() should have caught it
5274 =item Repeated format line will never terminate (~~ and @#)
5276 (F) Your format contains the ~~ repeat-until-blank sequence and a
5277 numeric field that will never go blank so that the repetition never
5278 terminates. You might use ^# instead. See L<perlform>.
5280 =item Replacement list is longer than search list
5282 (W misc) You have used a replacement list that is longer than the
5283 search list. So the additional elements in the replacement list
5286 =item '%s' resolved to '\o{%s}%d'
5288 (W misc, regexp) You wrote something like C<\08>, or C<\179> in a
5289 double-quotish string. All but the last digit is treated as a single
5290 character, specified in octal. The last digit is the next character in
5291 the string. To tell Perl that this is indeed what you want, you can use
5292 the C<\o{ }> syntax, or use exactly three digits to specify the octal
5295 =item Reversed %s= operator
5297 (W syntax) You wrote your assignment operator backwards. The = must
5298 always come last, to avoid ambiguity with subsequent unary operators.
5300 =item rewinddir() attempted on invalid dirhandle %s
5302 (W io) The dirhandle you tried to do a rewinddir() on is either closed
5303 or not really a dirhandle. Check your control flow.
5305 =item Scalars leaked: %d
5307 (S internal) Something went wrong in Perl's internal bookkeeping
5308 of scalars: not all scalar variables were deallocated by the time
5309 Perl exited. What this usually indicates is a memory leak, which
5310 is of course bad, especially if the Perl program is intended to be
5313 =item Scalar value @%s[%s] better written as $%s[%s]
5315 (W syntax) You've used an array slice (indicated by @) to select a
5316 single element of an array. Generally it's better to ask for a scalar
5317 value (indicated by $). The difference is that C<$foo[&bar]> always
5318 behaves like a scalar, both when assigning to it and when evaluating its
5319 argument, while C<@foo[&bar]> behaves like a list when you assign to it,
5320 and provides a list context to its subscript, which can do weird things
5321 if you're expecting only one subscript.
5323 On the other hand, if you were actually hoping to treat the array
5324 element as a list, you need to look into how references work, because
5325 Perl will not magically convert between scalars and lists for you. See
5328 =item Scalar value @%s{%s} better written as $%s{%s}
5330 (W syntax) You've used a hash slice (indicated by @) to select a single
5331 element of a hash. Generally it's better to ask for a scalar value
5332 (indicated by $). The difference is that C<$foo{&bar}> always behaves
5333 like a scalar, both when assigning to it and when evaluating its
5334 argument, while C<@foo{&bar}> behaves like a list when you assign to it,
5335 and provides a list context to its subscript, which can do weird things
5336 if you're expecting only one subscript.
5338 On the other hand, if you were actually hoping to treat the hash element
5339 as a list, you need to look into how references work, because Perl will
5340 not magically convert between scalars and lists for you. See
5343 =item Search pattern not terminated
5345 (F) The lexer couldn't find the final delimiter of a // or m{}
5346 construct. Remember that bracketing delimiters count nesting level.
5347 Missing the leading C<$> from a variable C<$m> may cause this error.
5349 Note that since Perl 5.10.0 a // can also be the I<defined-or>
5350 construct, not just the empty search pattern. Therefore code written
5351 in Perl 5.10.0 or later that uses the // as the I<defined-or> can be
5352 misparsed by pre-5.10.0 Perls as a non-terminated search pattern.
5354 =item seekdir() attempted on invalid dirhandle %s
5356 (W io) The dirhandle you are doing a seekdir() on is either closed or not
5357 really a dirhandle. Check your control flow.
5359 =item %sseek() on unopened filehandle
5361 (W unopened) You tried to use the seek() or sysseek() function on a
5362 filehandle that was either never opened or has since been closed.
5364 =item select not implemented
5366 (F) This machine doesn't implement the select() system call.
5368 =item Self-ties of arrays and hashes are not supported
5370 (F) Self-ties are of arrays and hashes are not supported in
5371 the current implementation.
5373 =item Semicolon seems to be missing
5375 (W semicolon) A nearby syntax error was probably caused by a missing
5376 semicolon, or possibly some other missing operator, such as a comma.
5378 =item semi-panic: attempt to dup freed string
5380 (S internal) The internal newSVsv() routine was called to duplicate a
5381 scalar that had previously been marked as free.
5383 =item sem%s not implemented
5385 (F) You don't have System V semaphore IPC on your system.
5387 =item send() on closed socket %s
5389 (W closed) The socket you're sending to got itself closed sometime
5390 before now. Check your control flow.
5392 =item Sequence "\c{" invalid
5394 (F) These three characters may not appear in sequence in a
5395 double-quotish context. This message is raised only on non-ASCII
5396 platforms (a different error message is output on ASCII ones). If you
5397 were intending to specify a control character with this sequence, you'll
5398 have to use a different way to specify it.
5400 =item Sequence (? incomplete in regex; marked by S<<-- HERE> in m/%s/
5402 (F) A regular expression ended with an incomplete extension (?. The
5403 S<<-- HERE> shows whereabouts in the regular expression the problem was
5404 discovered. See L<perlre>.
5406 =item Sequence (?%c...) not implemented in regex; marked by S<<-- HERE> in
5409 (F) A proposed regular expression extension has the character reserved
5410 but has not yet been written. The S<<-- HERE> shows whereabouts in the
5411 regular expression the problem was discovered. See L<perlre>.
5413 =item Sequence (?%s...) not recognized in regex; marked by S<<-- HERE> in
5416 (F) You used a regular expression extension that doesn't make sense.
5417 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5418 discovered. This may happen when using the C<(?^...)> construct to tell
5419 Perl to use the default regular expression modifiers, and you
5420 redundantly specify a default modifier. For other
5421 causes, see L<perlre>.
5423 =item Sequence (?#... not terminated in regex m/%s/
5425 (F) A regular expression comment must be terminated by a closing
5426 parenthesis. Embedded parentheses aren't allowed. See
5429 =item Sequence (?&... not terminated in regex; marked by S<<-- HERE> in
5432 (F) A named reference of the form C<(?&...)> was missing the final
5433 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5434 in the regular expression the problem was discovered.
5436 =item Sequence (?%c... not terminated in regex; marked by S<<-- HERE>
5439 (F) A named group of the form C<(?'...')> or C<< (?<...>) >> was missing the final
5440 closing quote or angle bracket. The S<<-- HERE> shows whereabouts in the
5441 regular expression the problem was discovered.
5443 =item Sequence (?(%c... not terminated in regex; marked by S<<-- HERE>
5446 (F) A named reference of the form C<(?('...')...)> or C<< (?(<...>)...) >> was
5447 missing the final closing quote or angle bracket after the name. The
5448 S<<-- HERE> shows whereabouts in the regular expression the problem was
5451 =item Sequence (?... not terminated in regex; marked by S<<-- HERE> in
5454 (F) There was no matching closing parenthesis for the '('. The
5455 S<<-- HERE> shows whereabouts in the regular expression the problem was
5458 =item Sequence \%s... not terminated in regex; marked by S<<-- HERE> in
5461 (F) The regular expression expects a mandatory argument following the escape
5462 sequence and this has been omitted or incorrectly written.
5464 =item Sequence (?{...}) not terminated with ')'
5466 (F) The end of the perl code contained within the {...} must be
5467 followed immediately by a ')'.
5469 =item Sequence (?PE<gt>... not terminated in regex; marked by S<<-- HERE> in m/%s/
5471 (F) A named reference of the form C<(?PE<gt>...)> was missing the final
5472 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5473 in the regular expression the problem was discovered.
5475 =item Sequence (?PE<lt>... not terminated in regex; marked by S<<-- HERE> in m/%s/
5477 (F) A named group of the form C<(?PE<lt>...E<gt>')> was missing the final
5478 closing angle bracket. The S<<-- HERE> shows whereabouts in the
5479 regular expression the problem was discovered.
5481 =item Sequence ?P=... not terminated in regex; marked by S<<-- HERE> in
5484 (F) A named reference of the form C<(?P=...)> was missing the final
5485 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5486 in the regular expression the problem was discovered.
5488 =item Sequence (?R) not terminated in regex m/%s/
5490 (F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
5493 =item Z<>500 Server error
5495 (A) This is the error message generally seen in a browser window
5496 when trying to run a CGI program (including SSI) over the web. The
5497 actual error text varies widely from server to server. The most
5498 frequently-seen variants are "500 Server error", "Method (something)
5499 not permitted", "Document contains no data", "Premature end of script
5500 headers", and "Did not produce a valid header".
5502 B<This is a CGI error, not a Perl error>.
5504 You need to make sure your script is executable, is accessible by
5505 the user CGI is running the script under (which is probably not the
5506 user account you tested it under), does not rely on any environment
5507 variables (like PATH) from the user it isn't running under, and isn't
5508 in a location where the CGI server can't find it, basically, more or
5509 less. Please see the following for more information:
5511 http://www.perl.org/CGI_MetaFAQ.html
5512 http://www.htmlhelp.org/faq/cgifaq.html
5513 http://www.w3.org/Security/Faq/
5515 You should also look at L<perlfaq9>.
5517 =item setegid() not implemented
5519 (F) You tried to assign to C<$)>, and your operating system doesn't
5520 support the setegid() system call (or equivalent), or at least Configure
5523 =item seteuid() not implemented
5525 (F) You tried to assign to C<< $> >>, and your operating system doesn't
5526 support the seteuid() system call (or equivalent), or at least Configure
5529 =item setpgrp can't take arguments
5531 (F) Your system has the setpgrp() from BSD 4.2, which takes no
5532 arguments, unlike POSIX setpgid(), which takes a process ID and process
5535 =item setrgid() not implemented
5537 (F) You tried to assign to C<$(>, and your operating system doesn't
5538 support the setrgid() system call (or equivalent), or at least Configure
5541 =item setruid() not implemented
5543 (F) You tried to assign to C<$<>, and your operating system doesn't
5544 support the setruid() system call (or equivalent), or at least Configure
5547 =item setsockopt() on closed socket %s
5549 (W closed) You tried to set a socket option on a closed socket. Did you
5550 forget to check the return value of your socket() call? See
5551 L<perlfunc/setsockopt>.
5553 =item Setting $/ to a reference to %s is forbidden
5555 (F) You assigned a reference to a scalar to C<$/> where the
5556 referenced item is not a positive integer. In older perls this B<appeared>
5557 to work the same as setting it to C<undef> but was in fact internally
5558 different, less efficient and with very bad luck could have resulted in
5559 your file being split by a stringified form of the reference.
5561 In Perl 5.20.0 this was changed so that it would be B<exactly> the same as
5562 setting C<$/> to undef, with the exception that this warning would be
5565 You are recommended to change your code to set C<$/> to C<undef> explicitly
5566 if you wish to slurp the file. As of Perl 5.28 assigning C<$/> to a
5567 reference to an integer which isn't positive is a fatal error.
5569 =item Setting $/ to %s reference is forbidden
5571 (F) You tried to assign a reference to a non integer to C<$/>. In older
5572 Perls this would have behaved similarly to setting it to a reference to
5573 a positive integer, where the integer was the address of the reference.
5574 As of Perl 5.20.0 this is a fatal error, to allow future versions of Perl
5575 to use non-integer refs for more interesting purposes.
5577 =item shm%s not implemented
5579 (F) You don't have System V shared memory IPC on your system.
5581 =item !=~ should be !~
5583 (W syntax) The non-matching operator is !~, not !=~. !=~ will be
5584 interpreted as the != (numeric not equal) and ~ (1's complement)
5585 operators: probably not what you intended.
5587 =item /%s/ should probably be written as "%s"
5589 (W syntax) You have used a pattern where Perl expected to find a string,
5590 as in the first argument to C<join>. Perl will treat the true or false
5591 result of matching the pattern against $_ as the string, which is
5592 probably not what you had in mind.
5594 =item shutdown() on closed socket %s
5596 (W closed) You tried to do a shutdown on a closed socket. Seems a bit
5599 =item SIG%s handler "%s" not defined
5601 (W signal) The signal handler named in %SIG doesn't, in fact, exist.
5602 Perhaps you put it into the wrong package?
5604 =item Slab leaked from cv %p
5606 (S) If you see this message, then something is seriously wrong with the
5607 internal bookkeeping of op trees. An op tree needed to be freed after
5608 a compilation error, but could not be found, so it was leaked instead.
5610 =item sleep(%u) too large
5612 (W overflow) You called C<sleep> with a number that was larger than
5613 it can reliably handle and C<sleep> probably slept for less time than
5616 =item Slurpy parameter not last
5618 (F) In a subroutine signature, you put something after a slurpy (array or
5619 hash) parameter. The slurpy parameter takes all the available arguments,
5620 so there can't be any left to fill later parameters.
5622 =item Smart matching a non-overloaded object breaks encapsulation
5624 (F) You should not use the C<~~> operator on an object that does not
5625 overload it: Perl refuses to use the object's underlying structure
5626 for the smart match.
5628 =item Smartmatch is experimental
5630 (S experimental::smartmatch) This warning is emitted if you
5631 use the smartmatch (C<~~>) operator. This is currently an experimental
5632 feature, and its details are subject to change in future releases of
5633 Perl. Particularly, its current behavior is noticed for being
5634 unnecessarily complex and unintuitive, and is very likely to be
5637 =item sort is now a reserved word
5639 (F) An ancient error message that almost nobody ever runs into anymore.
5640 But before sort was a keyword, people sometimes used it as a filehandle.
5642 =item Sorry, hash keys must be smaller than 2**31 bytes
5644 (F) You tried to create a hash containing a very large key, where "very
5645 large" means that it needs at least 2 gigabytes to store. Unfortunately,
5646 Perl doesn't yet handle such large hash keys. You should
5647 reconsider your design to avoid hashing such a long string directly.
5649 =item Source filters apply only to byte streams
5651 (F) You tried to activate a source filter (usually by loading a
5652 source filter module) within a string passed to C<eval>. This is
5653 not permitted under the C<unicode_eval> feature. Consider using
5654 C<evalbytes> instead. See L<feature>.
5656 =item splice() offset past end of array
5658 (W misc) You attempted to specify an offset that was past the end of
5659 the array passed to splice(). Splicing will instead commence at the
5660 end of the array, rather than past it. If this isn't what you want,
5661 try explicitly pre-extending the array by assigning $#array = $offset.
5662 See L<perlfunc/splice>.
5666 (P) The split was looping infinitely. (Obviously, a split shouldn't
5667 iterate more times than there are characters of input, which is what
5668 happened.) See L<perlfunc/split>.
5670 =item Statement unlikely to be reached
5672 (W exec) You did an exec() with some statement after it other than a
5673 die(). This is almost always an error, because exec() never returns
5674 unless there was a failure. You probably wanted to use system()
5675 instead, which does return. To suppress this warning, put the exec() in
5678 =item "state" subroutine %s can't be in a package
5680 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
5681 sense to try to declare one with a package qualifier on the front.
5683 =item "state %s" used in sort comparison
5685 (W syntax) The package variables $a and $b are used for sort comparisons.
5686 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
5687 sort comparison block, and the variable had earlier been declared as a
5688 lexical variable. Either qualify the sort variable with the package
5689 name, or rename the lexical variable.
5691 =item "state" variable %s can't be in a package
5693 (F) Lexically scoped variables aren't in a package, so it doesn't make
5694 sense to try to declare one with a package qualifier on the front. Use
5695 local() if you want to localize a package variable.
5697 =item stat() on unopened filehandle %s
5699 (W unopened) You tried to use the stat() function on a filehandle that
5700 was either never opened or has since been closed.
5702 =item Strings with code points over 0xFF may not be mapped into in-memory file handles
5704 (W utf8) You tried to open a reference to a scalar for read or append
5705 where the scalar contained code points over 0xFF. In-memory files
5706 model on-disk files and can only contain bytes.
5708 =item Stub found while resolving method "%s" overloading "%s" in package "%s"
5710 (P) Overloading resolution over @ISA tree may be broken by importation
5711 stubs. Stubs should never be implicitly created, but explicit calls to
5712 C<can> may break this.
5714 =item Subroutine "&%s" is not available
5716 (W closure) During compilation, an inner named subroutine or eval is
5717 attempting to capture an outer lexical subroutine that is not currently
5718 available. This can happen for one of two reasons. First, the lexical
5719 subroutine may be declared in an outer anonymous subroutine that has
5720 not yet been created. (Remember that named subs are created at compile
5721 time, while anonymous subs are created at run-time.) For example,
5723 sub { my sub a {...} sub f { \&a } }
5725 At the time that f is created, it can't capture the current "a" sub,
5726 since the anonymous subroutine hasn't been created yet. Conversely, the
5727 following won't give a warning since the anonymous subroutine has by now
5728 been created and is live:
5730 sub { my sub a {...} eval 'sub f { \&a }' }->();
5732 The second situation is caused by an eval accessing a lexical subroutine
5733 that has gone out of scope, for example,
5741 Here, when the '\&a' in the eval is being compiled, f() is not currently
5742 being executed, so its &a is not available for capture.
5744 =item "%s" subroutine &%s masks earlier declaration in same %s
5746 (W misc) A "my" or "state" subroutine has been redeclared in the
5747 current scope or statement, effectively eliminating all access to
5748 the previous instance. This is almost always a typographical error.
5749 Note that the earlier subroutine will still exist until the end of
5750 the scope or until all closure references to it are destroyed.
5752 =item Subroutine %s redefined
5754 (W redefine) You redefined a subroutine. To suppress this warning, say
5757 no warnings 'redefine';
5758 eval "sub name { ... }";
5761 =item Subroutine "%s" will not stay shared
5763 (W closure) An inner (nested) I<named> subroutine is referencing a "my"
5764 subroutine defined in an outer named subroutine.
5766 When the inner subroutine is called, it will see the value of the outer
5767 subroutine's lexical subroutine as it was before and during the *first*
5768 call to the outer subroutine; in this case, after the first call to the
5769 outer subroutine is complete, the inner and outer subroutines will no
5770 longer share a common value for the lexical subroutine. In other words,
5771 it will no longer be shared. This will especially make a difference
5772 if the lexical subroutines accesses lexical variables declared in its
5775 This problem can usually be solved by making the inner subroutine
5776 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
5777 reference lexical subroutines in outer subroutines are created, they
5778 are automatically rebound to the current values of such lexical subs.
5780 =item Substitution loop
5782 (P) The substitution was looping infinitely. (Obviously, a substitution
5783 shouldn't iterate more times than there are characters of input, which
5784 is what happened.) See the discussion of substitution in
5785 L<perlop/"Regexp Quote-Like Operators">.
5787 =item Substitution pattern not terminated
5789 (F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
5790 construct. Remember that bracketing delimiters count nesting level.
5791 Missing the leading C<$> from variable C<$s> may cause this error.
5793 =item Substitution replacement not terminated
5795 (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
5796 construct. Remember that bracketing delimiters count nesting level.
5797 Missing the leading C<$> from variable C<$s> may cause this error.
5799 =item substr outside of string
5801 (W substr)(F) You tried to reference a substr() that pointed outside of
5802 a string. That is, the absolute value of the offset was larger than the
5803 length of the string. See L<perlfunc/substr>. This warning is fatal if
5804 substr is used in an lvalue context (as the left hand side of an
5805 assignment or as a subroutine argument for example).
5807 =item sv_upgrade from type %d down to type %d
5809 (P) Perl tried to force the upgrade of an SV to a type which was actually
5810 inferior to its current type.
5812 =item SWASHNEW didn't return an HV ref
5814 (P) Something went wrong internally when Perl was trying to look up
5817 =item Switch (?(condition)... contains too many branches in regex; marked by
5818 S<<-- HERE> in m/%s/
5820 (F) A (?(condition)if-clause|else-clause) construct can have at most
5821 two branches (the if-clause and the else-clause). If you want one or
5822 both to contain alternation, such as using C<this|that|other>, enclose
5823 it in clustering parentheses:
5825 (?(condition)(?:this|that|other)|else-clause)
5827 The S<<-- HERE> shows whereabouts in the regular expression the problem
5828 was discovered. See L<perlre>.
5830 =item Switch condition not recognized in regex; marked by S<<-- HERE> in
5833 (F) The condition part of a (?(condition)if-clause|else-clause) construct
5834 is not known. The condition must be one of the following:
5836 (1) (2) ... true if 1st, 2nd, etc., capture matched
5837 (<NAME>) ('NAME') true if named capture matched
5838 (?=...) (?<=...) true if subpattern matches
5839 (?!...) (?<!...) true if subpattern fails to match
5840 (?{ CODE }) true if code returns a true value
5841 (R) true if evaluating inside recursion
5842 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
5843 (R&NAME) true if directly inside named capture
5844 (DEFINE) always false; for defining named subpatterns
5846 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5847 discovered. See L<perlre>.
5849 =item Switch (?(condition)... not terminated in regex; marked by
5850 S<<-- HERE> in m/%s/
5852 (F) You omitted to close a (?(condition)...) block somewhere
5853 in the pattern. Add a closing parenthesis in the appropriate
5854 position. See L<perlre>.
5856 =item switching effective %s is not implemented
5858 (F) While under the C<use filetest> pragma, we cannot switch the real
5859 and effective uids or gids.
5863 (F) Probably means you had a syntax error. Common reasons include:
5865 A keyword is misspelled.
5866 A semicolon is missing.
5868 An opening or closing parenthesis is missing.
5869 An opening or closing brace is missing.
5870 A closing quote is missing.
5872 Often there will be another error message associated with the syntax
5873 error giving more information. (Sometimes it helps to turn on B<-w>.)
5874 The error message itself often tells you where it was in the line when
5875 it decided to give up. Sometimes the actual error is several tokens
5876 before this, because Perl is good at understanding random input.
5877 Occasionally the line number may be misleading, and once in a blue moon
5878 the only way to figure out what's triggering the error is to call
5879 C<perl -c> repeatedly, chopping away half the program each time to see
5880 if the error went away. Sort of the cybernetic version of S<20 questions>.
5882 =item syntax error at line %d: '%s' unexpected
5884 (A) You've accidentally run your script through the Bourne shell instead
5885 of Perl. Check the #! line, or manually feed your script into Perl
5888 =item syntax error in file %s at line %d, next 2 tokens "%s"
5890 (F) This error is likely to occur if you run a perl5 script through
5891 a perl4 interpreter, especially if the next 2 tokens are "use strict"
5892 or "my $var" or "our $var".
5894 =item Syntax error in (?[...]) in regex m/%s/
5896 (F) Perl could not figure out what you meant inside this construct; this
5897 notifies you that it is giving up trying.
5901 (F) The final summary message when a C<perl -c> succeeds.
5903 =item sysread() on closed filehandle %s
5905 (W closed) You tried to read from a closed filehandle.
5907 =item sysread() on unopened filehandle %s
5909 (W unopened) You tried to read from a filehandle that was never opened.
5911 =item System V %s is not implemented on this machine
5913 (F) You tried to do something with a function beginning with "sem",
5914 "shm", or "msg" but that System V IPC is not implemented in your
5915 machine. In some machines the functionality can exist but be
5916 unconfigured. Consult your system support.
5918 =item syswrite() on closed filehandle %s
5920 (W closed) The filehandle you're writing to got itself closed sometime
5921 before now. Check your control flow.
5923 =item C<-T> and C<-B> not implemented on filehandles
5925 (F) Perl can't peek at the stdio buffer of filehandles when it doesn't
5926 know about your kind of stdio. You'll have to use a filename instead.
5928 =item Target of goto is too deeply nested
5930 (F) You tried to use C<goto> to reach a label that was too deeply nested
5931 for Perl to reach. Perl is doing you a favor by refusing.
5933 =item telldir() attempted on invalid dirhandle %s
5935 (W io) The dirhandle you tried to telldir() is either closed or not really
5936 a dirhandle. Check your control flow.
5938 =item tell() on unopened filehandle
5940 (W unopened) You tried to use the tell() function on a filehandle that
5941 was either never opened or has since been closed.
5943 =item That use of $[ is unsupported
5945 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
5946 as a compiler directive. You may say only one of
5955 This is to prevent the problem of one module changing the array base out
5956 from under another module inadvertently. See L<perlvar/$[> and L<arybase>.
5958 =item The bitwise feature is experimental
5960 (S experimental::bitwise) This warning is emitted if you use bitwise
5961 operators (C<& | ^ ~ &. |. ^. ~.>) with the "bitwise" feature enabled.
5962 Simply suppress the warning if you want to use the feature, but know
5963 that in doing so you are taking the risk of using an experimental
5964 feature which may change or be removed in a future Perl version:
5966 no warnings "experimental::bitwise";
5967 use feature "bitwise";
5970 =item The crypt() function is unimplemented due to excessive paranoia.
5972 (F) Configure couldn't find the crypt() function on your machine,
5973 probably because your vendor didn't supply it, probably because they
5974 think the U.S. Government thinks it's a secret, or at least that they
5975 will continue to pretend that it is. And if you quote me on that, I
5978 =item The experimental declared_refs feature is not enabled
5980 (F) To declare references to variables, as in C<my \%x>, you must first enable
5983 no warnings "experimental::declared_refs";
5984 use feature "declared_refs";
5986 =item The %s function is unimplemented
5988 (F) The function indicated isn't implemented on this architecture,
5989 according to the probings of Configure.
5991 =item The regex_sets feature is experimental
5993 (S experimental::regex_sets) This warning is emitted if you
5994 use the syntax S<C<(?[ ])>> in a regular expression.
5995 The details of this feature are subject to change.
5996 if you want to use it, but know that in doing so you
5997 are taking the risk of using an experimental feature which may
5998 change in a future Perl version, you can do this to silence the
6001 no warnings "experimental::regex_sets";
6003 =item The signatures feature is experimental
6005 (S experimental::signatures) This warning is emitted if you unwrap a
6006 subroutine's arguments using a signature. Simply suppress the warning
6007 if you want to use the feature, but know that in doing so you are taking
6008 the risk of using an experimental feature which may change or be removed
6009 in a future Perl version:
6011 no warnings "experimental::signatures";
6012 use feature "signatures";
6013 sub foo ($left, $right) { ... }
6015 =item The stat preceding %s wasn't an lstat
6017 (F) It makes no sense to test the current stat buffer for symbolic
6018 linkhood if the last stat that wrote to the stat buffer already went
6019 past the symlink to get to the real file. Use an actual filename
6022 =item The 'unique' attribute may only be applied to 'our' variables
6024 (F) This attribute was never supported on C<my> or C<sub> declarations.
6026 =item This Perl can't reset CRTL environ elements (%s)
6028 =item This Perl can't set CRTL environ elements (%s=%s)
6030 (W internal) Warnings peculiar to VMS. You tried to change or delete an
6031 element of the CRTL's internal environ array, but your copy of Perl
6032 wasn't built with a CRTL that contained the setenv() function. You'll
6033 need to rebuild Perl with a CRTL that does, or redefine
6034 F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
6035 target of the change to
6036 %ENV which produced the warning.
6038 =item This Perl has not been built with support for randomized hash key traversal but something called Perl_hv_rand_set().
6040 (F) Something has attempted to use an internal API call which
6041 depends on Perl being compiled with the default support for randomized hash
6042 key traversal, but this Perl has been compiled without it. You should
6043 report this warning to the relevant upstream party, or recompile perl
6044 with default options.
6046 =item times not implemented
6048 (F) Your version of the C library apparently doesn't do times(). I
6049 suspect you're not running on Unix.
6051 =item "-T" is on the #! line, it must also be used on the command line
6053 (X) The #! line (or local equivalent) in a Perl script contains
6054 the B<-T> option (or the B<-t> option), but Perl was not invoked with
6055 B<-T> in its command line. This is an error because, by the time
6056 Perl discovers a B<-T> in a script, it's too late to properly taint
6057 everything from the environment. So Perl gives up.
6059 If the Perl script is being executed as a command using the #!
6060 mechanism (or its local equivalent), this error can usually be
6061 fixed by editing the #! line so that the B<-%c> option is a part of
6062 Perl's first argument: e.g. change C<perl -n -%c> to C<perl -%c -n>.
6064 If the Perl script is being executed as C<perl scriptname>, then the
6065 B<-%c> option must appear on the command line: C<perl -%c scriptname>.
6067 =item To%s: illegal mapping '%s'
6069 (F) You tried to define a customized To-mapping for lc(), lcfirst,
6070 uc(), or ucfirst() (or their string-inlined versions), but you
6071 specified an illegal mapping.
6072 See L<perlunicode/"User-Defined Character Properties">.
6074 =item Too deeply nested ()-groups
6076 (F) Your template contains ()-groups with a ridiculously deep nesting level.
6078 =item Too few args to syscall
6080 (F) There has to be at least one argument to syscall() to specify the
6081 system call to call, silly dilly.
6083 =item Too few arguments for subroutine '%s'
6085 (F) A subroutine using a signature received too few arguments than
6086 required by the signature. The caller of the subroutine is presumably
6089 The message attempts to include the name of the called subroutine. If the
6090 subroutine has been aliased, the subroutine's original name will be shown,
6091 regardless of what name the caller used.
6093 =item Too late for "-%s" option
6095 (X) The #! line (or local equivalent) in a Perl script contains the
6096 B<-M>, B<-m> or B<-C> option.
6098 In the case of B<-M> and B<-m>, this is an error because those options
6099 are not intended for use inside scripts. Use the C<use> pragma instead.
6101 The B<-C> option only works if it is specified on the command line as
6102 well (with the same sequence of letters or numbers following). Either
6103 specify this option on the command line, or, if your system supports
6104 it, make your script executable and run it directly instead of passing
6107 =item Too late to run %s block
6109 (W void) A CHECK or INIT block is being defined during run time proper,
6110 when the opportunity to run them has already passed. Perhaps you are
6111 loading a file with C<require> or C<do> when you should be using C<use>
6112 instead. Or perhaps you should put the C<require> or C<do> inside a
6115 =item Too many args to syscall
6117 (F) Perl supports a maximum of only 14 args to syscall().
6119 =item Too many arguments for %s
6121 (F) The function requires fewer arguments than you specified.
6123 =item Too many arguments for subroutine '%s'
6125 (F) A subroutine using a signature received too many arguments than
6126 required by the signature. The caller of the subroutine is presumably
6129 The message attempts to include the name of the called subroutine. If the
6130 subroutine has been aliased, the subroutine's original name will be shown,
6131 regardless of what name the caller used.
6135 (A) You've accidentally run your script through B<csh> instead of Perl.
6136 Check the #! line, or manually feed your script into Perl yourself.
6140 (A) You've accidentally run your script through B<csh> instead of Perl.
6141 Check the #! line, or manually feed your script into Perl yourself.
6143 =item Trailing \ in regex m/%s/
6145 (F) The regular expression ends with an unbackslashed backslash.
6146 Backslash it. See L<perlre>.
6148 =item Transliteration pattern not terminated
6150 (F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
6151 or y/// or y[][] construct. Missing the leading C<$> from variables
6152 C<$tr> or C<$y> may cause this error.
6154 =item Transliteration replacement not terminated
6156 (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
6157 y/// or y[][] construct.
6159 =item '%s' trapped by operation mask
6161 (F) You tried to use an operator from a Safe compartment in which it's
6162 disallowed. See L<Safe>.
6164 =item truncate not implemented
6166 (F) Your machine doesn't implement a file truncation mechanism that
6167 Configure knows about.
6169 =item Type of arg %d to &CORE::%s must be %s
6171 (F) The subroutine in question in the CORE package requires its argument
6172 to be a hard reference to data of the specified type. Overloading is
6173 ignored, so a reference to an object that is not the specified type, but
6174 nonetheless has overloading to handle it, will still not be accepted.
6176 =item Type of arg %d to %s must be %s (not %s)
6178 (F) This function requires the argument in that position to be of a
6179 certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
6180 %NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
6181 {EXPR} forms as an explicit dereference. See L<perlref>.
6183 =item umask not implemented
6185 (F) Your machine doesn't implement the umask function and you tried to
6186 use it to restrict permissions for yourself (EXPR & 0700).
6188 =item Unbalanced context: %d more PUSHes than POPs
6190 (S internal) The exit code detected an internal inconsistency in how
6191 many execution contexts were entered and left.
6193 =item Unbalanced saves: %d more saves than restores
6195 (S internal) The exit code detected an internal inconsistency in how
6196 many values were temporarily localized.
6198 =item Unbalanced scopes: %d more ENTERs than LEAVEs
6200 (S internal) The exit code detected an internal inconsistency in how
6201 many blocks were entered and left.
6203 =item Unbalanced string table refcount: (%d) for "%s"
6205 (S internal) On exit, Perl found some strings remaining in the shared
6206 string table used for copy on write and for hash keys. The entries
6207 should have been freed, so this indicates a bug somewhere.
6209 =item Unbalanced tmps: %d more allocs than frees
6211 (S internal) The exit code detected an internal inconsistency in how
6212 many mortal scalars were allocated and freed.
6214 =item Undefined format "%s" called
6216 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6217 another package? See L<perlform>.
6219 =item Undefined sort subroutine "%s" called
6221 (F) The sort comparison routine specified doesn't seem to exist.
6222 Perhaps it's in a different package? See L<perlfunc/sort>.
6224 =item Undefined subroutine &%s called
6226 (F) The subroutine indicated hasn't been defined, or if it was, it has
6227 since been undefined.
6229 =item Undefined subroutine called
6231 (F) The anonymous subroutine you're trying to call hasn't been defined,
6232 or if it was, it has since been undefined.
6234 =item Undefined subroutine in sort
6236 (F) The sort comparison routine specified is declared but doesn't seem
6237 to have been defined yet. See L<perlfunc/sort>.
6239 =item Undefined top format "%s" called
6241 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6242 another package? See L<perlform>.
6244 =item Undefined value assigned to typeglob
6246 (W misc) An undefined value was assigned to a typeglob, a la
6247 C<*foo = undef>. This does nothing. It's possible that you really mean
6250 =item %s: Undefined variable
6252 (A) You've accidentally run your script through B<csh> instead of Perl.
6253 Check the #! line, or manually feed your script into Perl yourself.
6255 =item Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through in regex; marked by S<<-- HERE> in m/%s/
6257 (D deprecated, regexp) The simple rule to remember, if you want to
6258 match a literal C<{> character (U+007B C<LEFT CURLY BRACKET>) in a
6259 regular expression pattern, is to escape each literal instance of it in
6260 some way. Generally easiest is to precede it with a backslash, like
6261 C<\{> or enclose it in square brackets (C<[{]>). If the pattern
6262 delimiters are also braces, any matching right brace (C<}>) should
6263 also be escaped to avoid confusing the parser, for example,
6267 Forcing literal C<{> characters to be escaped will enable the Perl
6268 language to be extended in various ways in future releases. To avoid
6269 needlessly breaking existing code, the restriction is is not enforced in
6270 contexts where there are unlikely to ever be extensions that could
6271 conflict with the use there of C<{> as a literal.
6273 In this release of Perl, some literal uses of C<{> are fatal, and some
6274 still just deprecated. This is because of an oversight: some uses of a
6275 literal C<{> that should have raised a deprecation warning starting in
6276 v5.20 did not warn until v5.26. By making the already-warned uses fatal
6277 now, some of the planned extensions can be made to the language sooner.
6278 The cases which are still allowed will be fatal in Perl 5.30.
6280 The contexts where no warnings or errors are raised are:
6286 as the first character in a pattern, or following C<^> indicating to
6287 anchor the match to the beginning of a line.
6291 as the first character following a C<|> indicating alternation.
6295 as the first character in a parenthesized grouping like
6302 as the first character following a quantifier
6309 The text of the message above is duplicated below to allow splain (and
6310 'use diagnostics') to work. Since one is fatal, and one not, they can't
6311 be combined as one message. And since the non-fatal one is temporary,
6312 there's no real need to enhance perldiag to handle this transient case.
6314 =item Unescaped left brace in regex is illegal here in regex;
6315 marked by S<<-- HERE> in m/%s/
6317 (F) The simple rule to remember, if you want to
6318 match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
6319 regular expression pattern, is to escape each literal instance of it in
6320 some way. Generally easiest is to precede it with a backslash, like
6321 C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
6322 delimiters are also braces, any matching right brace (C<"}">) should
6323 also be escaped to avoid confusing the parser, for example,
6327 Forcing literal C<"{"> characters to be escaped will enable the Perl
6328 language to be extended in various ways in future releases. To avoid
6329 needlessly breaking existing code, the restriction is is not enforced in
6330 contexts where there are unlikely to ever be extensions that could
6331 conflict with the use there of C<"{"> as a literal.
6333 In this release of Perl, some literal uses of C<"{"> are fatal, and some
6334 still just deprecated. This is because of an oversight: some uses of a
6335 literal C<"{"> that should have raised a deprecation warning starting in
6336 v5.20 did not warn until v5.26. By making the already-warned uses fatal
6337 now, some of the planned extensions can be made to the language sooner.
6339 The contexts where no warnings or errors are raised are:
6345 as the first character in a pattern, or following C<"^"> indicating to
6346 anchor the match to the beginning of a line.
6350 as the first character following a C<"|"> indicating alternation.
6354 as the first character in a parenthesized grouping like
6361 as the first character following a quantifier
6367 =item Unescaped literal '%c' in regex; marked by <-- HERE in m/%s/
6369 (W regexp) (only under C<S<use re 'strict'>>)
6371 Within the scope of C<S<use re 'strict'>> in a regular expression
6372 pattern, you included an unescaped C<}> or C<]> which was interpreted
6373 literally. These two characters are sometimes metacharacters, and
6374 sometimes literals, depending on what precedes them in the
6375 pattern. This is unlike the similar C<)> which is always a
6376 metacharacter unless escaped.
6378 This action at a distance, perhaps a large distance, can lead to Perl
6379 silently misinterpreting what you meant, so when you specify that you
6380 want extra checking by C<S<use re 'strict'>>, this warning is generated.
6381 If you meant the character as a literal, simply confirm that to Perl by
6382 preceding the character with a backslash, or make it into a bracketed
6383 character class (like C<[}]>). If you meant it as closing a
6384 corresponding C<[> or C<{>, you'll need to look back through the pattern
6385 to find out why that isn't happening.
6387 =item unexec of %s into %s failed!
6389 (F) The unexec() routine failed for some reason. See your local FSF
6390 representative, who probably put it there in the first place.
6392 =item Unexpected binary operator '%c' with no preceding operand in regex;
6393 marked by S<<-- HERE> in m/%s/
6395 (F) You had something like this:
6399 where the C<"|"> is a binary operator with an operand on the right, but
6400 no operand on the left.
6402 =item Unexpected character in regex; marked by S<<-- HERE> in m/%s/
6404 (F) You had something like this:
6408 Within C<(?[ ])>, no literal characters are allowed unless they are
6409 within an inner pair of square brackets, like
6413 Another possibility is that you forgot a backslash. Perl isn't smart
6414 enough to figure out what you really meant.
6416 =item Unexpected constant lvalue entersub entry via type/targ %d:%d
6418 (P) When compiling a subroutine call in lvalue context, Perl failed an
6419 internal consistency check. It encountered a malformed op tree.
6421 =item Unexpected exit %u
6423 (S) exit() was called or the script otherwise finished gracefully when
6424 C<PERL_EXIT_WARN> was set in C<PL_exit_flags>.
6426 =item Unexpected exit failure %d
6428 (S) An uncaught die() was called when C<PERL_EXIT_WARN> was set in
6431 =item Unexpected ')' in regex; marked by S<<-- HERE> in m/%s/
6433 (F) You had something like this:
6435 (?[ ( \p{Digit} + ) ])
6437 The C<")"> is out-of-place. Something apparently was supposed to
6438 be combined with the digits, or the C<"+"> shouldn't be there, or
6439 something like that. Perl can't figure out what was intended.
6441 =item Unexpected '(' with no preceding operator in regex; marked by
6442 S<<-- HERE> in m/%s/
6444 (F) You had something like this:
6446 (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
6448 There should be an operator before the C<"(">, as there's
6449 no indication as to how the digits are to be combined
6450 with the characters in the Lao and Thai scripts.
6452 =item Unicode non-character U+%X is not recommended for open interchange
6454 (S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
6455 defined by the Unicode standard to be non-characters. Those
6456 are legal codepoints, but are reserved for internal use; so,
6457 applications shouldn't attempt to exchange them. An application
6458 may not be expecting any of these characters at all, and receiving
6459 them may lead to bugs. If you know what you are doing you can
6460 turn off this warning by C<no warnings 'nonchar';>.
6462 This is not really a "severe" error, but it is supposed to be
6463 raised by default even if warnings are not enabled, and currently
6464 the only way to do that in Perl is to mark it as serious.
6466 =item Unicode surrogate U+%X is illegal in UTF-8
6468 (S surrogate) You had a UTF-16 surrogate in a context where they are
6469 not considered acceptable. These code points, between U+D800 and
6470 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6471 internally allows all unsigned integer code points (up to the size limit
6472 available on your platform), including surrogates. But these can cause
6473 problems when being input or output, which is likely where this message
6474 came from. If you really really know what you are doing you can turn
6475 off this warning by C<no warnings 'surrogate';>.
6477 =item Unknown charname '%s'
6479 (F) The name you used inside C<\N{}> is unknown to Perl. Check the
6480 spelling. You can say C<use charnames ":loose"> to not have to be
6481 so precise about spaces, hyphens, and capitalization on standard Unicode
6482 names. (Any custom aliases that have been created must be specified
6483 exactly, regardless of whether C<:loose> is used or not.) This error may
6484 also happen if the C<\N{}> is not in the scope of the corresponding
6485 C<S<use charnames>>.
6489 (P) Perl was about to print an error message in C<$@>, but the C<$@> variable
6490 did not exist, even after an attempt to create it.
6492 =item Unknown open() mode '%s'
6494 (F) The second argument of 3-argument open() is not among the list
6495 of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
6496 C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
6498 =item Unknown PerlIO layer "%s"
6500 (W layer) An attempt was made to push an unknown layer onto the Perl I/O
6501 system. (Layers take care of transforming data between external and
6502 internal representations.) Note that some layers, such as C<mmap>,
6503 are not supported in all environments. If your program didn't
6504 explicitly request the failing operation, it may be the result of the
6505 value of the environment variable PERLIO.
6507 =item Unknown process %x sent message to prime_env_iter: %s
6509 (P) An error peculiar to VMS. Perl was reading values for %ENV before
6510 iterating over it, and someone else stuck a message in the stream of
6511 data Perl expected. Someone's very confused, or perhaps trying to
6512 subvert Perl's population of %ENV for nefarious purposes.
6514 =item Unknown regex modifier "%s"
6516 (F) Alphanumerics immediately following the closing delimiter
6517 of a regular expression pattern are interpreted by Perl as modifier
6518 flags for the regex. One of the ones you specified is invalid. One way
6519 this can happen is if you didn't put in white space between the end of
6520 the regex and a following alphanumeric operator:
6522 if ($a =~ /foo/and $bar == 3) { ... }
6524 The C<"a"> is a valid modifier flag, but the C<"n"> is not, and raises
6525 this error. Likely what was meant instead was:
6527 if ($a =~ /foo/ and $bar == 3) { ... }
6529 =item Unknown "re" subpragma '%s' (known ones are: %s)
6531 (W) You tried to use an unknown subpragma of the "re" pragma.
6533 =item Unknown switch condition (?(...)) in regex; marked by S<<-- HERE> in
6536 (F) The condition part of a (?(condition)if-clause|else-clause) construct
6537 is not known. The condition must be one of the following:
6539 (1) (2) ... true if 1st, 2nd, etc., capture matched
6540 (<NAME>) ('NAME') true if named capture matched
6541 (?=...) (?<=...) true if subpattern matches
6542 (?!...) (?<!...) true if subpattern fails to match
6543 (?{ CODE }) true if code returns a true value
6544 (R) true if evaluating inside recursion
6545 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
6546 (R&NAME) true if directly inside named capture
6547 (DEFINE) always false; for defining named subpatterns
6549 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6550 discovered. See L<perlre>.
6552 =item Unknown Unicode option letter '%c'
6554 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6555 of the C<-C> switch for the list of known options.
6557 =item Unknown Unicode option value %d
6559 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6560 of the C<-C> switch for the list of known options.
6562 =item Unknown verb pattern '%s' in regex; marked by S<<-- HERE> in m/%s/
6564 (F) You either made a typo or have incorrectly put a C<*> quantifier
6565 after an open brace in your pattern. Check the pattern and review
6566 L<perlre> for details on legal verb patterns.
6568 =item Unknown warnings category '%s'
6570 (F) An error issued by the C<warnings> pragma. You specified a warnings
6571 category that is unknown to perl at this point.
6573 Note that if you want to enable a warnings category registered by a
6574 module (e.g. C<use warnings 'File::Find'>), you must have loaded this
6577 =item Unmatched [ in regex; marked by S<<-- HERE> in m/%s/
6579 (F) The brackets around a character class must match. If you wish to
6580 include a closing bracket in a character class, backslash it or put it
6581 first. The S<<-- HERE> shows whereabouts in the regular expression the
6582 problem was discovered. See L<perlre>.
6584 =item Unmatched ( in regex; marked by S<<-- HERE> in m/%s/
6586 =item Unmatched ) in regex; marked by S<<-- HERE> in m/%s/
6588 (F) Unbackslashed parentheses must always be balanced in regular
6589 expressions. If you're a vi user, the % key is valuable for finding
6590 the matching parenthesis. The S<<-- HERE> shows whereabouts in the
6591 regular expression the problem was discovered. See L<perlre>.
6593 =item Unmatched right %s bracket
6595 (F) The lexer counted more closing curly or square brackets than opening
6596 ones, so you're probably missing a matching opening bracket. As a
6597 general rule, you'll find the missing one (so to speak) near the place
6598 you were last editing.
6600 =item Unquoted string "%s" may clash with future reserved word
6602 (W reserved) You used a bareword that might someday be claimed as a
6603 reserved word. It's best to put such a word in quotes, or capitalize it
6604 somehow, or insert an underbar into it. You might also declare it as a
6607 =item Unrecognized character %s; marked by S<<-- HERE> after %s near column
6610 (F) The Perl parser has no idea what to do with the specified character
6611 in your Perl script (or eval) near the specified column. Perhaps you
6612 tried to run a compressed script, a binary program, or a directory as
6615 =item Unrecognized escape \%c in character class in regex; marked by
6616 S<<-- HERE> in m/%s/
6618 (F) You used a backslash-character combination which is not
6619 recognized by Perl inside character classes. This is a fatal
6620 error when the character class is used within C<(?[ ])>.
6622 =item Unrecognized escape \%c in character class passed through in regex;
6623 marked by S<<-- HERE> in m/%s/
6625 (W regexp) You used a backslash-character combination which is not
6626 recognized by Perl inside character classes. The character was
6627 understood literally, but this may change in a future version of Perl.
6628 The S<<-- HERE> shows whereabouts in the regular expression the
6629 escape was discovered.
6631 =item Unrecognized escape \%c passed through
6633 (W misc) You used a backslash-character combination which is not
6634 recognized by Perl. The character was understood literally, but this may
6635 change in a future version of Perl.
6637 =item Unrecognized escape \%s passed through in regex; marked by
6638 S<<-- HERE> in m/%s/
6640 (W regexp) You used a backslash-character combination which is not
6641 recognized by Perl. The character(s) were understood literally, but
6642 this may change in a future version of Perl. The S<<-- HERE> shows
6643 whereabouts in the regular expression the escape was discovered.
6645 =item Unrecognized signal name "%s"
6647 (F) You specified a signal name to the kill() function that was not
6648 recognized. Say C<kill -l> in your shell to see the valid signal names
6651 =item Unrecognized switch: -%s (-h will show valid options)
6653 (F) You specified an illegal option to Perl. Don't do that. (If you
6654 think you didn't do that, check the #! line to see if it's supplying the
6655 bad switch on your behalf.)
6657 =item Unsuccessful %s on filename containing newline
6659 (W newline) A file operation was attempted on a filename, and that
6660 operation failed, PROBABLY because the filename contained a newline,
6661 PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
6663 =item Unsupported directory function "%s" called
6665 (F) Your machine doesn't support opendir() and readdir().
6667 =item Unsupported function %s
6669 (F) This machine doesn't implement the indicated function, apparently.
6670 At least, Configure doesn't think so.
6672 =item Unsupported function fork
6674 (F) Your version of executable does not support forking.
6676 Note that under some systems, like OS/2, there may be different flavors
6677 of Perl executables, some of which may support fork, some not. Try
6678 changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
6680 =item Unsupported script encoding %s
6682 (F) Your program file begins with a Unicode Byte Order Mark (BOM) which
6683 declares it to be in a Unicode encoding that Perl cannot read.
6685 =item Unsupported socket function "%s" called
6687 (F) Your machine doesn't support the Berkeley socket mechanism, or at
6688 least that's what Configure thought.
6690 =item Unterminated attribute list
6692 (F) The lexer found something other than a simple identifier at the
6693 start of an attribute, and it wasn't a semicolon or the start of a
6694 block. Perhaps you terminated the parameter list of the previous
6695 attribute too soon. See L<attributes>.
6697 =item Unterminated attribute parameter in attribute list
6699 (F) The lexer saw an opening (left) parenthesis character while parsing
6700 an attribute list, but the matching closing (right) parenthesis
6701 character was not found. You may need to add (or remove) a backslash
6702 character to get your parentheses to balance. See L<attributes>.
6704 =item Unterminated compressed integer
6706 (F) An argument to unpack("w",...) was incompatible with the BER
6707 compressed integer format and could not be converted to an integer.
6708 See L<perlfunc/pack>.
6710 =item Unterminated delimiter for here document
6712 (F) This message occurs when a here document label has an initial
6713 quotation mark but the final quotation mark is missing. Perhaps
6722 =item Unterminated \g... pattern in regex; marked by S<<-- HERE> in m/%s/
6724 =item Unterminated \g{...} pattern in regex; marked by S<<-- HERE> in m/%s/
6726 (F) In a regular expression, you had a C<\g> that wasn't followed by a
6727 proper group reference. In the case of C<\g{>, the closing brace is
6728 missing; otherwise the C<\g> must be followed by an integer. Fix the
6731 =item Unterminated <> operator
6733 (F) The lexer saw a left angle bracket in a place where it was expecting
6734 a term, so it's looking for the corresponding right angle bracket, and
6735 not finding it. Chances are you left some needed parentheses out
6736 earlier in the line, and you really meant a "less than".
6738 =item Unterminated verb pattern argument in regex; marked by S<<-- HERE> in
6741 (F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
6742 the pattern with a C<)>. Fix the pattern and retry.
6744 =item Unterminated verb pattern in regex; marked by S<<-- HERE> in m/%s/
6746 (F) You used a pattern of the form C<(*VERB)> but did not terminate
6747 the pattern with a C<)>. Fix the pattern and retry.
6749 =item untie attempted while %d inner references still exist
6751 (W untie) A copy of the object returned from C<tie> (or C<tied>) was
6752 still valid when C<untie> was called.
6754 =item Usage: POSIX::%s(%s)
6756 (F) You called a POSIX function with incorrect arguments.
6757 See L<POSIX/FUNCTIONS> for more information.
6759 =item Usage: Win32::%s(%s)
6761 (F) You called a Win32 function with incorrect arguments.
6762 See L<Win32> for more information.
6764 =item $[ used in %s (did you mean $] ?)
6766 (W syntax) You used C<$[> in a comparison, such as:
6772 You probably meant to use C<$]> instead. C<$[> is the base for indexing
6773 arrays. C<$]> is the Perl version number in decimal.
6775 =item Use "%s" instead of "%s"
6777 (F) The second listed construct is no longer legal. Use the first one
6780 =item Useless assignment to a temporary
6782 (W misc) You assigned to an lvalue subroutine, but what
6783 the subroutine returned was a temporary scalar about to
6784 be discarded, so the assignment had no effect.
6786 =item Useless (?-%s) - don't use /%s modifier in regex; marked by
6787 S<<-- HERE> in m/%s/
6789 (W regexp) You have used an internal modifier such as (?-o) that has no
6790 meaning unless removed from the entire regexp:
6792 if ($string =~ /(?-o)$pattern/o) { ... }
6796 if ($string =~ /$pattern/) { ... }
6798 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6799 discovered. See L<perlre>.
6801 =item Useless localization of %s
6803 (W syntax) The localization of lvalues such as C<local($x=10)> is legal,
6804 but in fact the local() currently has no effect. This may change at
6805 some point in the future, but in the meantime such code is discouraged.
6807 =item Useless (?%s) - use /%s modifier in regex; marked by S<<-- HERE> in
6810 (W regexp) You have used an internal modifier such as (?o) that has no
6811 meaning unless applied to the entire regexp:
6813 if ($string =~ /(?o)$pattern/) { ... }
6817 if ($string =~ /$pattern/o) { ... }
6819 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6820 discovered. See L<perlre>.
6822 =item Useless use of attribute "const"
6824 (W misc) The C<const> attribute has no effect except
6825 on anonymous closure prototypes. You applied it to
6826 a subroutine via L<attributes.pm|attributes>. This is only useful
6827 inside an attribute handler for an anonymous subroutine.
6829 =item Useless use of /d modifier in transliteration operator
6831 (W misc) You have used the /d modifier where the searchlist has the
6832 same length as the replacelist. See L<perlop> for more information
6833 about the /d modifier.
6835 =item Useless use of \E
6837 (W misc) You have a \E in a double-quotish string without a C<\U>,
6838 C<\L> or C<\Q> preceding it.
6840 =item Useless use of greediness modifier '%c' in regex; marked by S<<-- HERE> in m/%s/
6842 (W regexp) You specified something like these:
6847 The C<"?"> and C<"+"> don't have any effect, as they modify whether to
6848 match more or fewer when there is a choice, and by specifying to match
6849 exactly a given numer, there is no room left for a choice.
6851 =item Useless use of %s in void context
6853 (W void) You did something without a side effect in a context that does
6854 nothing with the return value, such as a statement that doesn't return a
6855 value from a block, or the left side of a scalar comma operator. Very
6856 often this points not to stupidity on your part, but a failure of Perl
6857 to parse your program the way you thought it would. For example, you'd
6858 get this if you mixed up your C precedence with Python precedence and
6863 when you meant to say
6865 ($one, $two) = (1, 2);
6867 Another common error is to use ordinary parentheses to construct a list
6868 reference when you should be using square or curly brackets, for
6873 when you should have said
6877 The square brackets explicitly turn a list value into a scalar value,
6878 while parentheses do not. So when a parenthesized list is evaluated in
6879 a scalar context, the comma is treated like C's comma operator, which
6880 throws away the left argument, which is not what you want. See
6881 L<perlref> for more on this.
6883 This warning will not be issued for numerical constants equal to 0 or 1
6884 since they are often used in statements like
6886 1 while sub_with_side_effects();
6888 String constants that would normally evaluate to 0 or 1 are warned
6891 =item Useless use of (?-p) in regex; marked by S<<-- HERE> in m/%s/
6893 (W regexp) The C<p> modifier cannot be turned off once set. Trying to do
6896 =item Useless use of "re" pragma
6898 (W) You did C<use re;> without any arguments. That isn't very useful.
6900 =item Useless use of sort in scalar context
6902 (W void) You used sort in scalar context, as in :
6906 This is not very useful, and perl currently optimizes this away.
6908 =item Useless use of %s with no values
6910 (W syntax) You used the push() or unshift() function with no arguments
6911 apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
6912 usually have any effect on the array, so is completely useless. It's
6913 possible in principle that push(@tied_array) could have some effect
6914 if the array is tied to a class which implements a PUSH method. If so,
6915 you can write it as C<push(@tied_array,())> to avoid this warning.
6917 =item "use" not allowed in expression
6919 (F) The "use" keyword is recognized and executed at compile time, and
6920 returns no useful value. See L<perlmod>.
6922 =item Use of assignment to $[ is deprecated
6924 (D deprecated) The C<$[> variable (index of the first element in an array)
6925 is deprecated. See L<perlvar/"$[">.
6927 =item Use of bare << to mean <<"" is forbidden
6929 (F) You are now required to use the explicitly quoted
6930 form if you wish to use an empty line as the terminator of the
6933 Use of a bare terminator was deprecated in Perl 5.000, and
6934 is a fatal error as of Perl 5.28.
6936 =item Use of /c modifier is meaningless in s///
6938 (W regexp) You used the /c modifier in a substitution. The /c
6939 modifier is not presently meaningful in substitutions.
6941 =item Use of /c modifier is meaningless without /g
6943 (W regexp) You used the /c modifier with a regex operand, but didn't
6944 use the /g modifier. Currently, /c is meaningful only when /g is
6945 used. (This may change in the future.)
6947 =item Use of code point 0x%s is not allowed; the permissible max is 0x%s.
6949 (F) You used a code point that is not allowed, because it is too large.
6950 Unicode only allows code points up to 0x10FFFF, but Perl allows much
6951 larger ones. Earlier versions of Perl allowed code points above IV_MAX
6952 (0x7FFFFFF on 32-bit platforms, 0x7FFFFFFFFFFFFFFF on 64-bit platforms),
6953 however, this could possibly break the perl interpreter in some constructs,
6954 including causing it to hang in a few cases.
6956 If your code is to run on various platforms, keep in mind that the upper
6957 limit depends on the platform. It is much larger on 64-bit word sizes
6960 The use of out of range code points was deprecated in Perl 5.24, and
6961 became a fatal error in Perl 5.28.
6963 =item Use of each() on hash after insertion without resetting hash iterator results in undefined behavior
6965 (S internal) The behavior of C<each()> after insertion is undefined;
6966 it may skip items, or visit items more than once. Consider using
6967 C<keys()> instead of C<each()>.
6969 =item Infinite recursion via empty pattern
6971 (F) You tried to use the empty pattern inside of a regex code block,
6972 for instance C</(?{ s!!! })/>, which resulted in re-executing
6973 the same pattern, which is an infinite loop which is broken by
6974 throwing an exception.
6976 =item Use of := for an empty attribute list is not allowed
6978 (F) The construction C<my $x := 42> used to parse as equivalent to
6979 C<my $x : = 42> (applying an empty attribute list to C<$x>).
6980 This construct was deprecated in 5.12.0, and has now been made a syntax
6981 error, so C<:=> can be reclaimed as a new operator in the future.
6983 If you need an empty attribute list, for example in a code generator, add
6984 a space before the C<=>.
6986 =item Use of %s for non-UTF-8 locale is wrong. Assuming a UTF-8 locale
6988 (W locale) You are matching a regular expression using locale rules,
6989 and the specified construct was encountered. This construct is only
6990 valid for UTF-8 locales, which the current locale isn't. This doesn't
6991 make sense. Perl will continue, assuming a Unicode (UTF-8) locale, but
6992 the results are likely to be wrong.
6994 =item Use of freed value in iteration
6996 (F) Perhaps you modified the iterated array within the loop?
6997 This error is typically caused by code like the following:
7000 @a = () for (1,2,@a);
7002 You are not supposed to modify arrays while they are being iterated over.
7003 For speed and efficiency reasons, Perl internally does not do full
7004 reference-counting of iterated items, hence deleting such an item in the
7005 middle of an iteration causes Perl to see a freed value.
7007 =item Use of /g modifier is meaningless in split
7009 (W regexp) You used the /g modifier on the pattern for a C<split>
7010 operator. Since C<split> always tries to match the pattern
7011 repeatedly, the C</g> has no effect.
7013 =item Use of "goto" to jump into a construct is deprecated
7015 (D deprecated) Using C<goto> to jump from an outer scope into an inner
7016 scope is deprecated and should be avoided.
7018 This was deprecated in Perl 5.12.
7020 =item Use of inherited AUTOLOAD for non-method %s::%s() is no longer allowed
7022 (F) As an accidental feature, C<AUTOLOAD> subroutines were looked up as
7023 methods (using the C<@ISA> hierarchy), even when the subroutines to be
7024 autoloaded were called as plain functions (e.g. C<Foo::bar()>), not as
7025 methods (e.g. C<< Foo->bar() >> or C<< $obj->bar() >>).
7027 This was deprecated in Perl 5.004, and was made fatal in Perl 5.28.
7029 =item Use of %s in printf format not supported
7031 (F) You attempted to use a feature of printf that is accessible from
7032 only C. This usually means there's a better way to do it in Perl.
7034 =item Use of -l on filehandle%s
7036 (W io) A filehandle represents an opened file, and when you opened the file
7037 it already went past any symlink you are presumably trying to look for.
7038 The operation returned C<undef>. Use a filename instead.
7040 =item Use of reference "%s" as array index
7042 (W misc) You tried to use a reference as an array index; this probably
7043 isn't what you mean, because references in numerical context tend
7044 to be huge numbers, and so usually indicates programmer error.
7046 If you really do mean it, explicitly numify your reference, like so:
7047 C<$array[0+$ref]>. This warning is not given for overloaded objects,
7048 however, because you can overload the numification and stringification
7049 operators and then you presumably know what you are doing.
7051 =item Use of state $_ is experimental
7053 (S experimental::lexical_topic) Lexical $_ is an experimental feature and
7054 its behavior may change or even be removed in any future release of perl.
7055 See the explanation under L<perlvar/$_>.
7057 =item Use of strings with code points over 0xFF as arguments to %s
7058 operator is not allowed
7060 (F) You tried to use one of the string bitwise operators
7061 (C<&> or C<|> or C<^> or C<~>) on a string containing a code point over
7062 0xFF. The string bitwise operators treat their operands as strings of
7063 bytes, and values beyond 0xFF are nonsensical in this context.
7065 This became fatal in Perl 5.28.
7067 =item Use of strings with code points over 0xFF as arguments to C<vec>
7068 is deprecated. This will be a fatal error in Perl 5.32
7070 (D deprecated) You tried to use L<C<vec>|perlfunc/vec EXPR,OFFSET,BITS>
7071 on a string containing a code point over 0xFF, which is nonsensical here.
7073 Such usage will be a fatal error in Perl 5.32.
7075 =item Use of tainted arguments in %s is deprecated
7077 (W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
7078 arguments and at least one of them is tainted. This used to be allowed
7079 but will become a fatal error in a future version of perl. Untaint your
7080 arguments. See L<perlsec>.
7082 =item Use of unassigned code point or non-standalone grapheme for a
7083 delimiter will be a fatal error starting in Perl 5.30
7086 A grapheme is what appears to a native-speaker of a language to be a
7087 character. In Unicode (and hence Perl) a grapheme may actually be
7088 several adjacent characters that together form a complete grapheme. For
7089 example, there can be a base character, like "R" and an accent, like a
7090 circumflex "^", that appear when displayed to be a single character with
7091 the circumflex hovering over the "R". Perl currently allows things like
7092 that circumflex to be delimiters of strings, patterns, I<etc>. When
7093 displayed, the circumflex would look like it belongs to the character
7094 just to the left of it. In order to move the language to be able to
7095 accept graphemes as delimiters, we have to deprecate the use of
7096 delimiters which aren't graphemes by themselves. Also, a delimiter must
7097 already be assigned (or known to be never going to be assigned) to try
7098 to future-proof code, for otherwise code that works today would fail to
7099 compile if the currently unassigned delimiter ends up being something
7100 that isn't a stand-alone grapheme. Because Unicode is never going to
7102 L<non-character code points|perlunicode/Noncharacter code points>, nor
7103 L<code points that are above the legal Unicode maximum|
7104 perlunicode/Beyond Unicode code points>, those can be delimiters, and
7105 their use won't raise this warning.
7107 =item Use of uninitialized value%s
7109 (W uninitialized) An undefined value was used as if it were already
7110 defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
7111 To suppress this warning assign a defined value to your variables.
7113 To help you figure out what was undefined, perl will try to tell you
7114 the name of the variable (if any) that was undefined. In some cases
7115 it cannot do this, so it also tells you what operation you used the
7116 undefined value in. Note, however, that perl optimizes your program
7117 and the operation displayed in the warning may not necessarily appear
7118 literally in your program. For example, C<"that $foo"> is usually
7119 optimized into C<"that " . $foo>, and the warning will refer to the
7120 C<concatenation (.)> operator, even though there is no C<.> in
7123 =item "use re 'strict'" is experimental
7125 (S experimental::re_strict) The things that are different when a regular
7126 expression pattern is compiled under C<'strict'> are subject to change
7127 in future Perl releases in incompatible ways. This means that a pattern
7128 that compiles today may not in a future Perl release. This warning is
7129 to alert you to that risk.
7131 =item Use \x{...} for more than two hex characters in regex; marked by
7132 S<<-- HERE> in m/%s/
7134 (F) In a regular expression, you said something like
7138 Perl isn't sure if you meant this
7142 or if you meant this
7144 (?[ [ \x{BE} E F ] ])
7146 You need to add either braces or blanks to disambiguate.
7148 =item Using just the first character returned by \N{} in character class in
7149 regex; marked by S<<-- HERE> in m/%s/
7151 (W regexp) Named Unicode character escapes C<(\N{...})> may return
7152 a multi-character sequence. Even though a character class is
7153 supposed to match just one character of input, perl will match
7154 the whole thing correctly, except when the class is inverted
7155 (C<[^...]>), or the escape is the beginning or final end point of
7156 a range. For these, what should happen isn't clear at all. In
7157 these circumstances, Perl discards all but the first character
7158 of the returned sequence, which is not likely what you want.
7160 =item Using /u for '%s' instead of /%s in regex; marked by S<<-- HERE> in m/%s/
7162 (W regexp) You used a Unicode boundary (C<\b{...}> or C<\B{...}>) in a
7163 portion of a regular expression where the character set modifiers C</a>
7164 or C</aa> are in effect. These two modifiers indicate an ASCII
7165 interpretation, and this doesn't make sense for a Unicode defintion.
7166 The generated regular expression will compile so that the boundary uses
7167 all of Unicode. No other portion of the regular expression is affected.
7169 =item Using !~ with %s doesn't make sense
7171 (F) Using the C<!~> operator with C<s///r>, C<tr///r> or C<y///r> is
7172 currently reserved for future use, as the exact behavior has not
7173 been decided. (Simply returning the boolean opposite of the
7174 modified string is usually not particularly useful.)
7176 =item UTF-16 surrogate U+%X
7178 (S surrogate) You had a UTF-16 surrogate in a context where they are
7179 not considered acceptable. These code points, between U+D800 and
7180 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
7181 internally allows all unsigned integer code points (up to the size limit
7182 available on your platform), including surrogates. But these can cause
7183 problems when being input or output, which is likely where this message
7184 came from. If you really really know what you are doing you can turn
7185 off this warning by C<no warnings 'surrogate';>.
7187 =item Value of %s can be "0"; test with defined()
7189 (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
7190 C<each()>, or C<readdir()> as a boolean value. Each of these constructs
7191 can return a value of "0"; that would make the conditional expression
7192 false, which is probably not what you intended. When using these
7193 constructs in conditional expressions, test their values with the
7194 C<defined> operator.
7196 =item Value of CLI symbol "%s" too long
7198 (W misc) A warning peculiar to VMS. Perl tried to read the value of an
7199 %ENV element from a CLI symbol table, and found a resultant string
7200 longer than 1024 characters. The return value has been truncated to
7203 =item Variable "%s" is not available
7205 (W closure) During compilation, an inner named subroutine or eval is
7206 attempting to capture an outer lexical that is not currently available.
7207 This can happen for one of two reasons. First, the outer lexical may be
7208 declared in an outer anonymous subroutine that has not yet been created.
7209 (Remember that named subs are created at compile time, while anonymous
7210 subs are created at run-time.) For example,
7212 sub { my $a; sub f { $a } }
7214 At the time that f is created, it can't capture the current value of $a,
7215 since the anonymous subroutine hasn't been created yet. Conversely,
7216 the following won't give a warning since the anonymous subroutine has by
7217 now been created and is live:
7219 sub { my $a; eval 'sub f { $a }' }->();
7221 The second situation is caused by an eval accessing a variable that has
7222 gone out of scope, for example,
7230 Here, when the '$a' in the eval is being compiled, f() is not currently
7231 being executed, so its $a is not available for capture.
7233 =item Variable "%s" is not imported%s
7235 (S misc) With "use strict" in effect, you referred to a global variable
7236 that you apparently thought was imported from another module, because
7237 something else of the same name (usually a subroutine) is exported by
7238 that module. It usually means you put the wrong funny character on the
7239 front of your variable.
7241 =item Variable length lookbehind not implemented in regex m/%s/
7243 (F) Lookbehind is allowed only for subexpressions whose length is fixed and
7244 known at compile time. For positive lookbehind, you can use the C<\K>
7245 regex construct as a way to get the equivalent functionality. See
7246 L<(?<=pattern) and \K in perlre|perlre/\K>.
7248 There are non-obvious Unicode rules under C</i> that can match variably,
7249 but which you might not think could. For example, the substring C<"ss">
7250 can match the single character LATIN SMALL LETTER SHARP S. There are
7251 other sequences of ASCII characters that can match single ligature
7252 characters, such as LATIN SMALL LIGATURE FFI matching C<qr/ffi/i>.
7253 Starting in Perl v5.16, if you only care about ASCII matches, adding the
7254 C</aa> modifier to the regex will exclude all these non-obvious matches,
7255 thus getting rid of this message. You can also say C<S<use re qw(/aa)>>
7256 to apply C</aa> to all regular expressions compiled within its scope.
7259 =item "%s" variable %s masks earlier declaration in same %s
7261 (W misc) A "my", "our" or "state" variable has been redeclared in the
7262 current scope or statement, effectively eliminating all access to the
7263 previous instance. This is almost always a typographical error. Note
7264 that the earlier variable will still exist until the end of the scope
7265 or until all closure references to it are destroyed.
7267 =item Variable syntax
7269 (A) You've accidentally run your script through B<csh> instead
7270 of Perl. Check the #! line, or manually feed your script into
7273 =item Variable "%s" will not stay shared
7275 (W closure) An inner (nested) I<named> subroutine is referencing a
7276 lexical variable defined in an outer named subroutine.
7278 When the inner subroutine is called, it will see the value of
7279 the outer subroutine's variable as it was before and during the *first*
7280 call to the outer subroutine; in this case, after the first call to the
7281 outer subroutine is complete, the inner and outer subroutines will no
7282 longer share a common value for the variable. In other words, the
7283 variable will no longer be shared.
7285 This problem can usually be solved by making the inner subroutine
7286 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
7287 reference variables in outer subroutines are created, they
7288 are automatically rebound to the current values of such variables.
7290 =item vector argument not supported with alpha versions
7292 (S printf) The %vd (s)printf format does not support version objects
7295 =item Verb pattern '%s' has a mandatory argument in regex; marked by
7296 S<<-- HERE> in m/%s/
7298 (F) You used a verb pattern that requires an argument. Supply an
7299 argument or check that you are using the right verb.
7301 =item Verb pattern '%s' may not have an argument in regex; marked by
7302 S<<-- HERE> in m/%s/
7304 (F) You used a verb pattern that is not allowed an argument. Remove the
7305 argument or check that you are using the right verb.
7307 =item Version control conflict marker
7309 (F) The parser found a line starting with C<E<lt><<<<<<>,
7310 C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
7311 version control system to mark conflicts after a failed merge operation.
7313 =item Version number must be a constant number
7315 (P) The attempt to translate a C<use Module n.n LIST> statement into
7316 its equivalent C<BEGIN> block found an internal inconsistency with
7319 =item Version string '%s' contains invalid data; ignoring: '%s'
7321 (W misc) The version string contains invalid characters at the end, which
7324 =item Warning: something's wrong
7326 (W) You passed warn() an empty string (the equivalent of C<warn "">) or
7327 you called it with no args and C<$@> was empty.
7329 =item Warning: unable to close filehandle %s properly
7331 (S) The implicit close() done by an open() got an error indication on
7332 the close(). This usually indicates your file system ran out of disk
7335 =item Warning: unable to close filehandle properly: %s
7337 =item Warning: unable to close filehandle %s properly: %s
7339 (S io) There were errors during the implicit close() done on a filehandle
7340 when its reference count reached zero while it was still open, e.g.:
7343 open my $fh, '>', $file or die "open: '$file': $!\n";
7344 print $fh $data or die "print: $!";
7345 } # implicit close here
7347 Because various errors may only be detected by close() (e.g. buffering could
7348 allow the C<print> in this example to return true even when the disk is full),
7349 it is dangerous to ignore its result. So when it happens implicitly, perl
7350 will signal errors by warning.
7352 B<Prior to version 5.22.0, perl ignored such errors>, so the common idiom shown
7353 above was liable to cause B<silent data loss>.
7355 =item Warning: Use of "%s" without parentheses is ambiguous
7357 (S ambiguous) You wrote a unary operator followed by something that
7358 looks like a binary operator that could also have been interpreted as a
7359 term or unary operator. For instance, if you know that the rand
7360 function has a default argument of 1.0, and you write
7364 you may THINK you wrote the same thing as
7368 but in actual fact, you got
7372 So put in parentheses to say what you really mean.
7374 =item when is experimental
7376 (S experimental::smartmatch) C<when> depends on smartmatch, which is
7377 experimental. Additionally, it has several special cases that may
7378 not be immediately obvious, and their behavior may change or
7379 even be removed in any future release of perl. See the explanation
7380 under L<perlsyn/Experimental Details on given and when>.
7382 =item Wide character in %s
7384 (S utf8) Perl met a wide character (>255) when it wasn't expecting
7385 one. This warning is by default on for I/O (like print). The easiest
7386 way to quiet this warning is simply to add the C<:utf8> layer to the
7387 output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
7388 warning is to add C<no warnings 'utf8';> but that is often closer to
7389 cheating. In general, you are supposed to explicitly mark the
7390 filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
7392 =item Wide character (U+%X) in %s
7394 (W locale) While in a single-byte locale (I<i.e.>, a non-UTF-8
7395 one), a multi-byte character was encountered. Perl considers this
7396 character to be the specified Unicode code point. Combining non-UTF-8
7397 locales and Unicode is dangerous. Almost certainly some characters
7398 will have two different representations. For example, in the ISO 8859-7
7399 (Greek) locale, the code point 0xC3 represents a Capital Gamma. But so
7400 also does 0x393. This will make string comparisons unreliable.
7402 You likely need to figure out how this multi-byte character got mixed up
7403 with your single-byte locale (or perhaps you thought you had a UTF-8
7404 locale, but Perl disagrees).
7406 =item Within []-length '%c' not allowed
7408 (F) The count in the (un)pack template may be replaced by C<[TEMPLATE]>
7409 only if C<TEMPLATE> always matches the same amount of packed bytes that
7410 can be determined from the template alone. This is not possible if
7411 it contains any of the codes @, /, U, u, w or a *-length. Redesign
7414 =item %s() with negative argument
7416 (S misc) Certain operations make no sense with negative arguments.
7417 Warning is given and the operation is not done.
7419 =item write() on closed filehandle %s
7421 (W closed) The filehandle you're writing to got itself closed sometime
7422 before now. Check your control flow.
7424 =item %s "\x%X" does not map to Unicode
7426 (S utf8) When reading in different encodings, Perl tries to
7427 map everything into Unicode characters. The bytes you read
7428 in are not legal in this encoding. For example
7430 utf8 "\xE4" does not map to Unicode
7432 if you try to read in the a-diaereses Latin-1 as UTF-8.
7434 =item 'X' outside of string
7436 (F) You had a (un)pack template that specified a relative position before
7437 the beginning of the string being (un)packed. See L<perlfunc/pack>.
7439 =item 'x' outside of string in unpack
7441 (F) You had a pack template that specified a relative position after
7442 the end of the string being unpacked. See L<perlfunc/pack>.
7444 =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
7446 (F) And you probably never will, because you probably don't have the
7447 sources to your kernel, and your vendor probably doesn't give a rip
7448 about what you want. Your best bet is to put a setuid C wrapper around
7451 =item You need to quote "%s"
7453 (W syntax) You assigned a bareword as a signal handler name.
7454 Unfortunately, you already have a subroutine of that name declared,
7455 which means that Perl 5 will try to call the subroutine when the
7456 assignment is executed, which is probably not what you want. (If it IS
7457 what you want, put an & in front.)
7459 =item Your random numbers are not that random
7461 (F) When trying to initialize the random seed for hashes, Perl could
7462 not get any randomness out of your system. This usually indicates
7463 Something Very Wrong.
7465 =item Zero length \N{} in regex; marked by S<<-- HERE> in m/%s/
7467 (F) Named Unicode character escapes (C<\N{...}>) may return a zero-length
7468 sequence. Such an escape was used in an extended character class, i.e.
7469 C<(?[...])>, or under C<use re 'strict'>, which is not permitted. Check
7470 that the correct escape has been used, and the correct charnames handler
7471 is in scope. The S<<-- HERE> shows whereabouts in the regular
7472 expression the problem was discovered.
7478 L<warnings>, L<diagnostics>.