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 "locked" is deprecated
423 (D deprecated) You have used the attributes pragma to modify the
424 "locked" attribute on a code reference. The :locked attribute is
425 obsolete, has had no effect since 5005 threads were removed, and
426 will be removed in a future release of Perl 5.
428 =item Attribute prototype(%s) discards earlier prototype attribute in same sub
430 (W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
431 example. Since each sub can only have one prototype, the earlier
432 declaration(s) are discarded while the last one is applied.
434 =item Attribute "unique" is deprecated
436 (D deprecated) You have used the attributes pragma to modify
437 the "unique" attribute on an array, hash or scalar reference.
438 The :unique attribute has had no effect since Perl 5.8.8, and
439 will be removed in a future release of Perl 5.
441 =item av_reify called on tied array
443 (S debugging) This indicates that something went wrong and Perl got I<very>
444 confused about C<@_> or C<@DB::args> being tied.
446 =item Bad arg length for %s, is %u, should be %d
448 (F) You passed a buffer of the wrong size to one of msgctl(), semctl()
449 or shmctl(). In C parlance, the correct sizes are, respectively,
450 S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
451 S<sizeof(struct shmid_ds *)>.
453 =item Bad evalled substitution pattern
455 (F) You've used the C</e> switch to evaluate the replacement for a
456 substitution, but perl found a syntax error in the code to evaluate,
457 most likely an unexpected right brace '}'.
459 =item Bad filehandle: %s
461 (F) A symbol was passed to something wanting a filehandle, but the
462 symbol has no filehandle associated with it. Perhaps you didn't do an
463 open(), or did it in another package.
465 =item Bad free() ignored
467 (S malloc) An internal routine called free() on something that had never
468 been malloc()ed in the first place. Mandatory, but can be disabled by
469 setting environment variable C<PERL_BADFREE> to 0.
471 This message can be seen quite often with DB_File on systems with "hard"
472 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
473 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
477 (P) One of the internal hash routines was passed a null HV pointer.
479 =item Badly placed ()'s
481 (A) You've accidentally run your script through B<csh> instead
482 of Perl. Check the #! line, or manually feed your script into
485 =item Bad name after %s
487 (F) You started to name a symbol by using a package prefix, and then
488 didn't finish the symbol. In particular, you can't interpolate outside
497 $sym = "mypack::$var";
499 =item Bad plugin affecting keyword '%s'
501 (F) An extension using the keyword plugin mechanism violated the
504 =item Bad realloc() ignored
506 (S malloc) An internal routine called realloc() on something that
507 had never been malloc()ed in the first place. Mandatory, but can
508 be disabled by setting the environment variable C<PERL_BADFREE> to 1.
510 =item Bad symbol for array
512 (P) An internal request asked to add an array entry to something that
513 wasn't a symbol table entry.
515 =item Bad symbol for dirhandle
517 (P) An internal request asked to add a dirhandle entry to something
518 that wasn't a symbol table entry.
520 =item Bad symbol for filehandle
522 (P) An internal request asked to add a filehandle entry to something
523 that wasn't a symbol table entry.
525 =item Bad symbol for hash
527 (P) An internal request asked to add a hash entry to something that
528 wasn't a symbol table entry.
530 =item Bad symbol for scalar
532 (P) An internal request asked to add a scalar entry to something that
533 wasn't a symbol table entry.
535 =item Bareword found in conditional
537 (W bareword) The compiler found a bareword where it expected a
538 conditional, which often indicates that an || or && was parsed as part
539 of the last argument of the previous construct, for example:
543 It may also indicate a misspelled constant that has been interpreted as
546 use constant TYPO => 1;
547 if (TYOP) { print "foo" }
549 The C<strict> pragma is useful in avoiding such errors.
551 =item Bareword in require contains "%s"
553 =item Bareword in require maps to disallowed filename "%s"
555 =item Bareword in require maps to empty filename
557 (F) The bareword form of require has been invoked with a filename which could
558 not have been generated by a valid bareword permitted by the parser. You
559 shouldn't be able to get this error from Perl code, but XS code may throw it
560 if it passes an invalid module name to C<Perl_load_module>.
562 =item Bareword in require must not start with a double-colon: "%s"
564 (F) In C<require Bare::Word>, the bareword is not allowed to start with a
565 double-colon. Write C<require ::Foo::Bar> as C<require Foo::Bar> instead.
567 =item Bareword "%s" not allowed while "strict subs" in use
569 (F) With "strict subs" in use, a bareword is only allowed as a
570 subroutine identifier, in curly brackets or to the left of the "=>"
571 symbol. Perhaps you need to predeclare a subroutine?
573 =item Bareword "%s" refers to nonexistent package
575 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
576 compiler saw no other uses of that namespace before that point. Perhaps
577 you need to predeclare a package?
579 =item BEGIN failed--compilation aborted
581 (F) An untrapped exception was raised while executing a BEGIN
582 subroutine. Compilation stops immediately and the interpreter is
585 =item BEGIN not safe after errors--compilation aborted
587 (F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
588 implies a C<BEGIN {}>) after one or more compilation errors had already
589 occurred. Since the intended environment for the C<BEGIN {}> could not
590 be guaranteed (due to the errors), and since subsequent code likely
591 depends on its correct operation, Perl just gave up.
593 =item \%d better written as $%d
595 (W syntax) Outside of patterns, backreferences live on as variables.
596 The use of backslashes is grandfathered on the right-hand side of a
597 substitution, but stylistically it's better to use the variable form
598 because other Perl programmers will expect it, and it works better if
599 there are more than 9 backreferences.
601 =item Binary number > 0b11111111111111111111111111111111 non-portable
603 (W portable) The binary number you specified is larger than 2**32-1
604 (4294967295) and therefore non-portable between systems. See
605 L<perlport> for more on portability concerns.
607 =item bind() on closed socket %s
609 (W closed) You tried to do a bind on a closed socket. Did you forget to
610 check the return value of your socket() call? See L<perlfunc/bind>.
612 =item binmode() on closed filehandle %s
614 (W unopened) You tried binmode() on a filehandle that was never opened.
615 Check your control flow and number of arguments.
617 =item Bit vector size > 32 non-portable
619 (W portable) Using bit vector sizes larger than 32 is non-portable.
621 =item Bizarre copy of %s
623 (P) Perl detected an attempt to copy an internal value that is not
626 =item Bizarre SvTYPE [%d]
628 (P) When starting a new thread or returning values from a thread, Perl
629 encountered an invalid data type.
631 =item Both or neither range ends should be Unicode in regex; marked by
634 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
636 In a bracketed character class in a regular expression pattern, you
637 had a range which has exactly one end of it specified using C<\N{}>, and
638 the other end is specified using a non-portable mechanism. Perl treats
639 the range as a Unicode range, that is, all the characters in it are
640 considered to be the Unicode characters, and which may be different code
641 points on some platforms Perl runs on. For example, C<[\N{U+06}-\x08]>
642 is treated as if you had instead said C<[\N{U+06}-\N{U+08}]>, that is it
643 matches the characters whose code points in Unicode are 6, 7, and 8.
644 But that C<\x08> might indicate that you meant something different, so
645 the warning gets raised.
647 =item Buffer overflow in prime_env_iter: %s
649 (W internal) A warning peculiar to VMS. While Perl was preparing to
650 iterate over %ENV, it encountered a logical name or symbol definition
651 which was too long, so it was truncated to the string shown.
653 =item Callback called exit
655 (F) A subroutine invoked from an external package via call_sv()
656 exited by calling exit.
658 =item %s() called too early to check prototype
660 (W prototype) You've called a function that has a prototype before the
661 parser saw a definition or declaration for it, and Perl could not check
662 that the call conforms to the prototype. You need to either add an
663 early prototype declaration for the subroutine in question, or move the
664 subroutine definition ahead of the call to get proper prototype
665 checking. Alternatively, if you are certain that you're calling the
666 function correctly, you may put an ampersand before the name to avoid
667 the warning. See L<perlsub>.
669 =item Calling POSIX::%s() is deprecated
671 (D deprecated) You called a function whose use is deprecated. See
672 the function's name in L<POSIX> for details.
676 (F) You passed an invalid number (like an infinity or not-a-number) to C<chr>.
678 =item Cannot compress %f in pack
680 (F) You tried compressing an infinity or not-a-number as an unsigned
681 integer with BER, which makes no sense.
683 =item Cannot compress integer in pack
685 (F) An argument to pack("w",...) was too large to compress.
686 The BER compressed integer format can only be used with positive
687 integers, and you attempted to compress a very large number (> 1e308).
688 See L<perlfunc/pack>.
690 =item Cannot compress negative numbers in pack
692 (F) An argument to pack("w",...) was negative. The BER compressed integer
693 format can only be used with positive integers. See L<perlfunc/pack>.
695 =item Cannot convert a reference to %s to typeglob
697 (F) You manipulated Perl's symbol table directly, stored a reference
698 in it, then tried to access that symbol via conventional Perl syntax.
699 The access triggers Perl to autovivify that typeglob, but it there is
700 no legal conversion from that type of reference to a typeglob.
702 =item Cannot copy to %s
704 (P) Perl detected an attempt to copy a value to an internal type that cannot
705 be directly assigned to.
707 =item Cannot find encoding "%s"
709 (S io) You tried to apply an encoding that did not exist to a filehandle,
710 either with open() or binmode().
712 =item Cannot pack %f with '%c'
714 (F) You tried converting an infinity or not-a-number to an integer,
715 which makes no sense.
717 =item Cannot printf %f with '%c'
719 (F) You tried printing an infinity or not-a-number as a character (%c),
720 which makes no sense. Maybe you meant '%s', or just stringifying it?
722 =item Cannot set tied @DB::args
724 (F) C<caller> tried to set C<@DB::args>, but found it tied. Tying C<@DB::args>
725 is not supported. (Before this error was added, it used to crash.)
727 =item Cannot tie unreifiable array
729 (P) You somehow managed to call C<tie> on an array that does not
730 keep a reference count on its arguments and cannot be made to
731 do so. Such arrays are not even supposed to be accessible to
732 Perl code, but are only used internally.
734 =item Cannot yet reorder sv_catpvfn() arguments from va_list
736 (F) Some XS code tried to use C<sv_catpvfn()> or a related function with a
737 format string that specifies explicit indexes for some of the elements, and
738 using a C-style variable-argument list (a C<va_list>). This is not currently
739 supported. XS authors wanting to do this must instead construct a C array
740 of C<SV*> scalars containing the arguments.
742 =item Can only compress unsigned integers in pack
744 (F) An argument to pack("w",...) was not an integer. The BER compressed
745 integer format can only be used with positive integers, and you attempted
746 to compress something else. See L<perlfunc/pack>.
748 =item Can't bless non-reference value
750 (F) Only hard references may be blessed. This is how Perl "enforces"
751 encapsulation of objects. See L<perlobj>.
753 =item Can't "break" in a loop topicalizer
755 (F) You called C<break>, but you're in a C<foreach> block rather than
756 a C<given> block. You probably meant to use C<next> or C<last>.
758 =item Can't "break" outside a given block
760 (F) You called C<break>, but you're not inside a C<given> block.
762 =item Can't call method "%s" on an undefined value
764 (F) You used the syntax of a method call, but the slot filled by the
765 object reference or package name contains an undefined value. Something
766 like this will reproduce the error:
769 process $BADREF 1,2,3;
770 $BADREF->process(1,2,3);
772 =item Can't call method "%s" on unblessed reference
774 (F) A method call must know in what package it's supposed to run. It
775 ordinarily finds this out from the object reference you supply, but you
776 didn't supply an object reference in this case. A reference isn't an
777 object reference until it has been blessed. See L<perlobj>.
779 =item Can't call method "%s" without a package or object reference
781 (F) You used the syntax of a method call, but the slot filled by the
782 object reference or package name contains an expression that returns a
783 defined value which is neither an object reference nor a package name.
784 Something like this will reproduce the error:
787 process $BADREF 1,2,3;
788 $BADREF->process(1,2,3);
790 =item Can't call mro_isa_changed_in() on anonymous symbol table
792 (P) Perl got confused as to whether a hash was a plain hash or a
793 symbol table hash when trying to update @ISA caches.
795 =item Can't call mro_method_changed_in() on anonymous symbol table
797 (F) An XS module tried to call C<mro_method_changed_in> on a hash that was
798 not attached to the symbol table.
800 =item Can't chdir to %s
802 (F) You called C<perl -x/foo/bar>, but F</foo/bar> is not a directory
803 that you can chdir to, possibly because it doesn't exist.
805 =item Can't check filesystem of script "%s" for nosuid
807 (P) For some reason you can't check the filesystem of the script for
810 =item Can't coerce %s to %s in %s
812 (F) Certain types of SVs, in particular real symbol table entries
813 (typeglobs), can't be forced to stop being what they are. So you can't
823 but then $foo no longer contains a glob.
825 =item Can't "continue" outside a when block
827 (F) You called C<continue>, but you're not inside a C<when>
830 =item Can't create pipe mailbox
832 (P) An error peculiar to VMS. The process is suffering from exhausted
833 quotas or other plumbing problems.
835 =item Can't declare %s in "%s"
837 (F) Only scalar, array, and hash variables may be declared as "my", "our" or
838 "state" variables. They must have ordinary identifiers as names.
840 =item Can't "default" outside a topicalizer
842 (F) You have used a C<default> block that is neither inside a
843 C<foreach> loop nor a C<given> block. (Note that this error is
844 issued on exit from the C<default> block, so you won't get the
845 error if you use an explicit C<continue>.)
847 =item Can't do inplace edit: %s is not a regular file
849 (S inplace) You tried to use the B<-i> switch on a special file, such as
850 a file in /dev, a FIFO or an uneditable directory. The file was ignored.
852 =item Can't do inplace edit on %s: %s
854 (S inplace) The creation of the new file failed for the indicated
857 =item Can't do inplace edit without backup
859 (F) You're on a system such as MS-DOS that gets confused if you try
860 reading from a deleted (but still opened) file. You have to say
861 C<-i.bak>, or some such.
863 =item Can't do inplace edit: %s would not be unique
865 (S inplace) Your filesystem does not support filenames longer than 14
866 characters and Perl was unable to create a unique filename during
867 inplace editing with the B<-i> switch. The file was ignored.
869 =item Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".
871 (W locale) You are 1) running under "C<use locale>"; 2) the current
872 locale is not a UTF-8 one; 3) you tried to do the designated case-change
873 operation on the specified Unicode character; and 4) the result of this
874 operation would mix Unicode and locale rules, which likely conflict.
875 Mixing of different rule types is forbidden, so the operation was not
876 done; instead the result is the indicated value, which is the best
877 available that uses entirely Unicode rules. That turns out to almost
878 always be the original character, unchanged.
880 It is generally a bad idea to mix non-UTF-8 locales and Unicode, and
881 this issue is one of the reasons why. This warning is raised when
882 Unicode rules would normally cause the result of this operation to
883 contain a character that is in the range specified by the locale,
884 0..255, and hence is subject to the locale's rules, not Unicode's.
886 If you are using locale purely for its characteristics related to things
887 like its numeric and time formatting (and not C<LC_CTYPE>), consider
888 using a restricted form of the locale pragma (see L<perllocale/The "use
889 locale" pragma>) like "S<C<use locale ':not_characters'>>".
891 Note that failed case-changing operations done as a result of
892 case-insensitive C</i> regular expression matching will show up in this
893 warning as having the C<fc> operation (as that is what the regular
894 expression engine calls behind the scenes.)
896 =item Can't do waitpid with flags
898 (F) This machine doesn't have either waitpid() or wait4(), so only
899 waitpid() without flags is emulated.
901 =item Can't emulate -%s on #! line
903 (F) The #! line specifies a switch that doesn't make sense at this
904 point. For example, it'd be kind of silly to put a B<-x> on the #!
907 =item Can't %s %s-endian %ss on this platform
909 (F) Your platform's byte-order is neither big-endian nor little-endian,
910 or it has a very strange pointer size. Packing and unpacking big- or
911 little-endian floating point values and pointers may not be possible.
912 See L<perlfunc/pack>.
914 =item Can't exec "%s": %s
916 (W exec) A system(), exec(), or piped open call could not execute the
917 named program for the indicated reason. Typical reasons include: the
918 permissions were wrong on the file, the file wasn't found in
919 C<$ENV{PATH}>, the executable in question was compiled for another
920 architecture, or the #! line in a script points to an interpreter that
921 can't be run for similar reasons. (Or maybe your system doesn't support
926 (F) Perl was trying to execute the indicated program for you because
927 that's what the #! line said. If that's not what you wanted, you may
928 need to mention "perl" on the #! line somewhere.
930 =item Can't execute %s
932 (F) You used the B<-S> switch, but the copies of the script to execute
933 found in the PATH did not have correct permissions.
935 =item Can't find an opnumber for "%s"
937 (F) A string of a form C<CORE::word> was given to prototype(), but there
938 is no builtin with the name C<word>.
940 =item Can't find label %s
942 (F) You said to goto a label that isn't mentioned anywhere that it's
943 possible for us to go to. See L<perlfunc/goto>.
945 =item Can't find %s on PATH
947 (F) You used the B<-S> switch, but the script to execute could not be
950 =item Can't find %s on PATH, '.' not in PATH
952 (F) You used the B<-S> switch, but the script to execute could not be
953 found in the PATH, or at least not with the correct permissions. The
954 script exists in the current directory, but PATH prohibits running it.
956 =item Can't find string terminator %s anywhere before EOF
958 (F) Perl strings can stretch over multiple lines. This message means
959 that the closing delimiter was omitted. Because bracketed quotes count
960 nesting levels, the following is missing its final parenthesis:
962 print q(The character '(' starts a side comment.);
964 If you're getting this error from a here-document, you may have
965 included unseen whitespace before or after your closing tag or there
966 may not be a linebreak after it. A good programmer's editor will have
967 a way to help you find these characters (or lack of characters). See
968 L<perlop> for the full details on here-documents.
970 =item Can't find Unicode property definition "%s"
972 =item Can't find Unicode property definition "%s" in regex; marked by <-- HERE in m/%s/
974 (F) The named property which you specified via C<\p> or C<\P> is not one
975 known to Perl. Perhaps you misspelled the name? See
976 L<perluniprops/Properties accessible through \p{} and \P{}>
977 for a complete list of available official
978 properties. If it is a
979 L<user-defined property|perlunicode/User-Defined Character Properties>
980 it must have been defined by the time the regular expression is
983 If you didn't mean to use a Unicode property, escape the C<\p>, either
984 by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, or
989 (F) A fatal error occurred while trying to fork while opening a
992 =item Can't fork, trying again in 5 seconds
994 (W pipe) A fork in a piped open failed with EAGAIN and will be retried
997 =item Can't get filespec - stale stat buffer?
999 (S) A warning peculiar to VMS. This arises because of the difference
1000 between access checks under VMS and under the Unix model Perl assumes.
1001 Under VMS, access checks are done by filename, rather than by bits in
1002 the stat buffer, so that ACLs and other protections can be taken into
1003 account. Unfortunately, Perl assumes that the stat buffer contains all
1004 the necessary information, and passes it, instead of the filespec, to
1005 the access-checking routine. It will try to retrieve the filespec using
1006 the device name and FID present in the stat buffer, but this works only
1007 if you haven't made a subsequent call to the CRTL stat() routine,
1008 because the device name is overwritten with each call. If this warning
1009 appears, the name lookup failed, and the access-checking routine gave up
1010 and returned FALSE, just to be conservative. (Note: The access-checking
1011 routine knows about the Perl C<stat> operator and file tests, so you
1012 shouldn't ever see this warning in response to a Perl command; it arises
1013 only if some internal code takes stat buffers lightly.)
1015 =item Can't get pipe mailbox device name
1017 (P) An error peculiar to VMS. After creating a mailbox to act as a
1018 pipe, Perl can't retrieve its name for later use.
1020 =item Can't get SYSGEN parameter value for MAXBUF
1022 (P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
1023 mailbox buffers to be, and didn't get an answer.
1025 =item Can't "goto" into the middle of a foreach loop
1027 (F) A "goto" statement was executed to jump into the middle of a foreach
1028 loop. You can't get there from here. See L<perlfunc/goto>.
1030 =item Can't "goto" out of a pseudo block
1032 (F) A "goto" statement was executed to jump out of what might look like
1033 a block, except that it isn't a proper block. This usually occurs if
1034 you tried to jump out of a sort() block or subroutine, which is a no-no.
1035 See L<perlfunc/goto>.
1037 =item Can't goto subroutine from an eval-%s
1039 (F) The "goto subroutine" call can't be used to jump out of an eval
1042 =item Can't goto subroutine from a sort sub (or similar callback)
1044 (F) The "goto subroutine" call can't be used to jump out of the
1045 comparison sub for a sort(), or from a similar callback (such
1046 as the reduce() function in List::Util).
1048 =item Can't goto subroutine outside a subroutine
1050 (F) The deeply magical "goto subroutine" call can only replace one
1051 subroutine call for another. It can't manufacture one out of whole
1052 cloth. In general you should be calling it out of only an AUTOLOAD
1053 routine anyway. See L<perlfunc/goto>.
1055 =item Can't ignore signal CHLD, forcing to default
1057 (W signal) Perl has detected that it is being run with the SIGCHLD
1058 signal (sometimes known as SIGCLD) disabled. Since disabling this
1059 signal will interfere with proper determination of exit status of child
1060 processes, Perl has reset the signal to its default value. This
1061 situation typically indicates that the parent program under which Perl
1062 may be running (e.g. cron) is being very careless.
1064 =item Can't kill a non-numeric process ID
1066 (F) Process identifiers must be (signed) integers. It is a fatal error to
1067 attempt to kill() an undefined, empty-string or otherwise non-numeric
1070 =item Can't "last" outside a loop block
1072 (F) A "last" statement was executed to break out of the current block,
1073 except that there's this itty bitty problem called there isn't a current
1074 block. Note that an "if" or "else" block doesn't count as a "loopish"
1075 block, as doesn't a block given to sort(), map() or grep(). You can
1076 usually double the curlies to get the same effect though, because the
1077 inner curlies will be considered a block that loops once. See
1080 =item Can't linearize anonymous symbol table
1082 (F) Perl tried to calculate the method resolution order (MRO) of a
1083 package, but failed because the package stash has no name.
1085 =item Can't load '%s' for module %s
1087 (F) The module you tried to load failed to load a dynamic extension.
1088 This may either mean that you upgraded your version of perl to one
1089 that is incompatible with your old dynamic extensions (which is known
1090 to happen between major versions of perl), or (more likely) that your
1091 dynamic extension was built against an older version of the library
1092 that is installed on your system. You may need to rebuild your old
1095 =item Can't localize lexical variable %s
1097 (F) You used local on a variable name that was previously declared as a
1098 lexical variable using "my" or "state". This is not allowed. If you
1099 want to localize a package variable of the same name, qualify it with
1102 =item Can't localize through a reference
1104 (F) You said something like C<local $$ref>, which Perl can't currently
1105 handle, because when it goes to restore the old value of whatever $ref
1106 pointed to after the scope of the local() is finished, it can't be sure
1107 that $ref will still be a reference.
1109 =item Can't locate %s
1111 (F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be found.
1112 Perl looks for the file in all the locations mentioned in @INC, unless
1113 the file name included the full path to the file. Perhaps you need
1114 to set the PERL5LIB or PERL5OPT environment variable to say where the
1115 extra library is, or maybe the script needs to add the library name
1116 to @INC. Or maybe you just misspelled the name of the file. See
1117 L<perlfunc/require> and L<lib>.
1119 =item Can't locate auto/%s.al in @INC
1121 (F) A function (or method) was called in a package which allows
1122 autoload, but there is no function to autoload. Most probable causes
1123 are a misprint in a function/method name or a failure to C<AutoSplit>
1124 the file, say, by doing C<make install>.
1126 =item Can't locate loadable object for module %s in @INC
1128 (F) The module you loaded is trying to load an external library, like
1129 for example, F<foo.so> or F<bar.dll>, but the L<DynaLoader> module was
1130 unable to locate this library. See L<DynaLoader>.
1132 =item Can't locate object method "%s" via package "%s"
1134 (F) You called a method correctly, and it correctly indicated a package
1135 functioning as a class, but that package doesn't define that particular
1136 method, nor does any of its base classes. See L<perlobj>.
1138 =item Can't locate object method "%s" via package "%s" (perhaps you forgot
1141 (F) You called a method on a class that did not exist, and the method
1142 could not be found in UNIVERSAL. This often means that a method
1143 requires a package that has not been loaded.
1145 =item Can't locate package %s for @%s::ISA
1147 (W syntax) The @ISA array contained the name of another package that
1148 doesn't seem to exist.
1150 =item Can't locate PerlIO%s
1152 (F) You tried to use in open() a PerlIO layer that does not exist,
1153 e.g. open(FH, ">:nosuchlayer", "somefile").
1155 =item Can't make list assignment to %ENV on this system
1157 (F) List assignment to %ENV is not supported on some systems, notably
1160 =item Can't make loaded symbols global on this platform while loading %s
1162 (S) A module passed the flag 0x01 to DynaLoader::dl_load_file() to request
1163 that symbols from the stated file are made available globally within the
1164 process, but that functionality is not available on this platform. Whilst
1165 the module likely will still work, this may prevent the perl interpreter
1166 from loading other XS-based extensions which need to link directly to
1167 functions defined in the C or XS code in the stated file.
1169 =item Can't modify %s in %s
1171 (F) You aren't allowed to assign to the item indicated, or otherwise try
1172 to change it, such as with an auto-increment.
1174 =item Can't modify nonexistent substring
1176 (P) The internal routine that does assignment to a substr() was handed
1179 =item Can't modify non-lvalue subroutine call of &%s
1181 (F) Subroutines meant to be used in lvalue context should be declared as
1182 such. See L<perlsub/"Lvalue subroutines">.
1184 =item Can't modify reference to %s in %s assignment
1186 (F) Only a limited number of constructs can be used as the argument to a
1187 reference constructor on the left-hand side of an assignment, and what
1188 you used was not one of them. See L<perlref/Assigning to References>.
1190 =item Can't modify reference to localized parenthesized array in list
1193 (F) Assigning to C<\local(@array)> or C<\(local @array)> is not supported, as
1194 it is not clear exactly what it should do. If you meant to make @array
1195 refer to some other array, use C<\@array = \@other_array>. If you want to
1196 make the elements of @array aliases of the scalars referenced on the
1197 right-hand side, use C<\(@array) = @scalar_refs>.
1199 =item Can't modify reference to parenthesized hash in list assignment
1201 (F) Assigning to C<\(%hash)> is not supported. If you meant to make %hash
1202 refer to some other hash, use C<\%hash = \%other_hash>. If you want to
1203 make the elements of %hash into aliases of the scalars referenced on the
1204 right-hand side, use a hash slice: C<\@hash{@keys} = @those_scalar_refs>.
1206 =item Can't msgrcv to read-only var
1208 (F) The target of a msgrcv must be modifiable to be used as a receive
1211 =item Can't "next" outside a loop block
1213 (F) A "next" statement was executed to reiterate the current block, but
1214 there isn't a current block. Note that an "if" or "else" block doesn't
1215 count as a "loopish" block, as doesn't a block given to sort(), map() or
1216 grep(). You can usually double the curlies to get the same effect
1217 though, because the inner curlies will be considered a block that loops
1218 once. See L<perlfunc/next>.
1220 =item Can't open %s: %s
1222 (S inplace) The implicit opening of a file through use of the C<< <> >>
1223 filehandle, either implicitly under the C<-n> or C<-p> command-line
1224 switches, or explicitly, failed for the indicated reason. Usually
1225 this is because you don't have read permission for a file which
1226 you named on the command line.
1228 (F) You tried to call perl with the B<-e> switch, but F</dev/null> (or
1229 your operating system's equivalent) could not be opened.
1231 =item Can't open a reference
1233 (W io) You tried to open a scalar reference for reading or writing,
1234 using the 3-arg open() syntax:
1238 but your version of perl is compiled without perlio, and this form of
1239 open is not supported.
1241 =item Can't open bidirectional pipe
1243 (W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
1244 You can try any of several modules in the Perl library to do this, such
1245 as IPC::Open2. Alternately, direct the pipe's output to a file using
1246 ">", and then read it in under a different file handle.
1248 =item Can't open error file %s as stderr
1250 (F) An error peculiar to VMS. Perl does its own command line
1251 redirection, and couldn't open the file specified after '2>' or '2>>' on
1252 the command line for writing.
1254 =item Can't open input file %s as stdin
1256 (F) An error peculiar to VMS. Perl does its own command line
1257 redirection, and couldn't open the file specified after '<' on the
1258 command line for reading.
1260 =item Can't open output file %s as stdout
1262 (F) An error peculiar to VMS. Perl does its own command line
1263 redirection, and couldn't open the file specified after '>' or '>>' on
1264 the command line for writing.
1266 =item Can't open output pipe (name: %s)
1268 (P) An error peculiar to VMS. Perl does its own command line
1269 redirection, and couldn't open the pipe into which to send data destined
1272 =item Can't open perl script "%s": %s
1274 (F) The script you specified can't be opened for the indicated reason.
1276 If you're debugging a script that uses #!, and normally relies on the
1277 shell's $PATH search, the -S option causes perl to do that search, so
1278 you don't have to type the path or C<`which $scriptname`>.
1280 =item Can't read CRTL environ
1282 (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
1283 from the CRTL's internal environment array and discovered the array was
1284 missing. You need to figure out where your CRTL misplaced its environ
1285 or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
1288 =item Can't redeclare "%s" in "%s"
1290 (F) A "my", "our" or "state" declaration was found within another declaration,
1291 such as C<my ($x, my($y), $z)> or C<our (my $x)>.
1293 =item Can't "redo" outside a loop block
1295 (F) A "redo" statement was executed to restart the current block, but
1296 there isn't a current block. Note that an "if" or "else" block doesn't
1297 count as a "loopish" block, as doesn't a block given to sort(), map()
1298 or grep(). You can usually double the curlies to get the same effect
1299 though, because the inner curlies will be considered a block that
1300 loops once. See L<perlfunc/redo>.
1302 =item Can't remove %s: %s, skipping file
1304 (S inplace) You requested an inplace edit without creating a backup
1305 file. Perl was unable to remove the original file to replace it with
1306 the modified file. The file was left unmodified.
1308 =item Can't rename %s to %s: %s, skipping file
1310 (S inplace) The rename done by the B<-i> switch failed for some reason,
1311 probably because you don't have write permission to the directory.
1313 =item Can't reopen input pipe (name: %s) in binary mode
1315 (P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
1316 to reopen it to accept binary data. Alas, it failed.
1318 =item Can't represent character for Ox%X on this platform
1320 (F) There is a hard limit to how big a character code point can be due
1321 to the fundamental properties of UTF-8, especially on EBCDIC
1322 platforms. The given code point exceeds that. The only work-around is
1323 to not use such a large code point.
1325 =item Can't reset %ENV on this system
1327 (F) You called C<reset('E')> or similar, which tried to reset
1328 all variables in the current package beginning with "E". In
1329 the main package, that includes %ENV. Resetting %ENV is not
1330 supported on some systems, notably VMS.
1332 =item Can't resolve method "%s" overloading "%s" in package "%s"
1334 (F)(P) Error resolving overloading specified by a method name (as
1335 opposed to a subroutine reference): no such method callable via the
1336 package. If the method name is C<???>, this is an internal error.
1338 =item Can't return %s from lvalue subroutine
1340 (F) Perl detected an attempt to return illegal lvalues (such as
1341 temporary or readonly values) from a subroutine used as an lvalue. This
1344 =item Can't return outside a subroutine
1346 (F) The return statement was executed in mainline code, that is, where
1347 there was no subroutine call to return out of. See L<perlsub>.
1349 =item Can't return %s to lvalue scalar context
1351 (F) You tried to return a complete array or hash from an lvalue
1352 subroutine, but you called the subroutine in a way that made Perl
1353 think you meant to return only one value. You probably meant to
1354 write parentheses around the call to the subroutine, which tell
1355 Perl that the call should be in list context.
1357 =item Can't stat script "%s"
1359 (P) For some reason you can't fstat() the script even though you have it
1360 open already. Bizarre.
1362 =item Can't take log of %g
1364 (F) For ordinary real numbers, you can't take the logarithm of a
1365 negative number or zero. There's a Math::Complex package that comes
1366 standard with Perl, though, if you really want to do that for the
1369 =item Can't take sqrt of %g
1371 (F) For ordinary real numbers, you can't take the square root of a
1372 negative number. There's a Math::Complex package that comes standard
1373 with Perl, though, if you really want to do that.
1375 =item Can't undef active subroutine
1377 (F) You can't undefine a routine that's currently running. You can,
1378 however, redefine it while it's running, and you can even undef the
1379 redefined subroutine while the old routine is running. Go figure.
1381 =item Can't upgrade %s (%d) to %d
1383 (P) The internal sv_upgrade routine adds "members" to an SV, making it
1384 into a more specialized kind of SV. The top several SV types are so
1385 specialized, however, that they cannot be interconverted. This message
1386 indicates that such a conversion was attempted.
1388 =item Can't use '%c' after -mname
1390 (F) You tried to call perl with the B<-m> switch, but you put something
1391 other than "=" after the module name.
1393 =item Can't use a hash as a reference
1395 (F) You tried to use a hash as a reference, as in
1396 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl
1397 <= 5.22.0 used to allow this syntax, but shouldn't
1398 have. This was deprecated in perl 5.6.1.
1400 =item Can't use an array as a reference
1402 (F) You tried to use an array as a reference, as in
1403 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.22.0
1404 used to allow this syntax, but shouldn't have. This
1405 was deprecated in perl 5.6.1.
1407 =item Can't use anonymous symbol table for method lookup
1409 (F) The internal routine that does method lookup was handed a symbol
1410 table that doesn't have a name. Symbol tables can become anonymous
1411 for example by undefining stashes: C<undef %Some::Package::>.
1413 =item Can't use an undefined value as %s reference
1415 (F) A value used as either a hard reference or a symbolic reference must
1416 be a defined value. This helps to delurk some insidious errors.
1418 =item Can't use bareword ("%s") as %s ref while "strict refs" in use
1420 (F) Only hard references are allowed by "strict refs". Symbolic
1421 references are disallowed. See L<perlref>.
1423 =item Can't use %! because Errno.pm is not available
1425 (F) The first time the C<%!> hash is used, perl automatically loads the
1426 Errno.pm module. The Errno module is expected to tie the %! hash to
1427 provide symbolic names for C<$!> errno values.
1429 =item Can't use both '<' and '>' after type '%c' in %s
1431 (F) A type cannot be forced to have both big-endian and little-endian
1432 byte-order at the same time, so this combination of modifiers is not
1433 allowed. See L<perlfunc/pack>.
1435 =item Can't use 'defined(@array)' (Maybe you should just omit the defined()?)
1437 (F) defined() is not useful on arrays because it
1438 checks for an undefined I<scalar> value. If you want to see if the
1439 array is empty, just use C<if (@array) { # not empty }> for example.
1441 =item Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)
1443 (F) C<defined()> is not usually right on hashes.
1445 Although C<defined %hash> is false on a plain not-yet-used hash, it
1446 becomes true in several non-obvious circumstances, including iterators,
1447 weak references, stash names, even remaining true after C<undef %hash>.
1448 These things make C<defined %hash> fairly useless in practice, so it now
1449 generates a fatal error.
1451 If a check for non-empty is what you wanted then just put it in boolean
1452 context (see L<perldata/Scalar values>):
1458 If you had C<defined %Foo::Bar::QUUX> to check whether such a package
1459 variable exists then that's never really been reliable, and isn't
1460 a good way to enquire about the features of a package, or whether
1463 =item Can't use %s for loop variable
1465 (P) The parser got confused when trying to parse a C<foreach> loop.
1467 =item Can't use global %s in "%s"
1469 (F) You tried to declare a magical variable as a lexical variable. This
1470 is not allowed, because the magic can be tied to only one location
1471 (namely the global variable) and it would be incredibly confusing to
1472 have variables in your program that looked like magical variables but
1475 =item Can't use '%c' in a group with different byte-order in %s
1477 (F) You attempted to force a different byte-order on a type
1478 that is already inside a group with a byte-order modifier.
1479 For example you cannot force little-endianness on a type that
1480 is inside a big-endian group.
1482 =item Can't use "my %s" in sort comparison
1484 (F) The global variables $a and $b are reserved for sort comparisons.
1485 You mentioned $a or $b in the same line as the <=> or cmp operator,
1486 and the variable had earlier been declared as a lexical variable.
1487 Either qualify the sort variable with the package name, or rename the
1490 =item Can't use %s ref as %s ref
1492 (F) You've mixed up your reference types. You have to dereference a
1493 reference of the type needed. You can use the ref() function to
1494 test the type of the reference, if need be.
1496 =item Can't use string ("%s") as %s ref while "strict refs" in use
1498 =item Can't use string ("%s"...) as %s ref while "strict refs" in use
1500 (F) You've told Perl to dereference a string, something which
1501 C<use strict> blocks to prevent it happening accidentally. See
1502 L<perlref/"Symbolic references">. This can be triggered by an C<@> or C<$>
1503 in a double-quoted string immediately before interpolating a variable,
1504 for example in C<"user @$twitter_id">, which says to treat the contents
1505 of C<$twitter_id> as an array reference; use a C<\> to have a literal C<@>
1506 symbol followed by the contents of C<$twitter_id>: C<"user \@$twitter_id">.
1508 =item Can't use subscript on %s
1510 (F) The compiler tried to interpret a bracketed expression as a
1511 subscript. But to the left of the brackets was an expression that
1512 didn't look like a hash or array reference, or anything else subscriptable.
1514 =item Can't use \%c to mean $%c in expression
1516 (W syntax) In an ordinary expression, backslash is a unary operator that
1517 creates a reference to its argument. The use of backslash to indicate a
1518 backreference to a matched substring is valid only as part of a regular
1519 expression pattern. Trying to do this in ordinary Perl code produces a
1520 value that prints out looking like SCALAR(0xdecaf). Use the $1 form
1523 =item Can't weaken a nonreference
1525 (F) You attempted to weaken something that was not a reference. Only
1526 references can be weakened.
1528 =item Can't "when" outside a topicalizer
1530 (F) You have used a when() block that is neither inside a C<foreach>
1531 loop nor a C<given> block. (Note that this error is issued on exit
1532 from the C<when> block, so you won't get the error if the match fails,
1533 or if you use an explicit C<continue>.)
1535 =item Can't x= to read-only value
1537 (F) You tried to repeat a constant value (often the undefined value)
1538 with an assignment operator, which implies modifying the value itself.
1539 Perhaps you need to copy the value to a temporary, and repeat that.
1541 =item Character following "\c" must be printable ASCII
1543 (F) In C<\cI<X>>, I<X> must be a printable (non-control) ASCII character.
1545 Note that ASCII characters that don't map to control characters are
1546 discouraged, and will generate the warning (when enabled)
1547 L</""\c%c" is more clearly written simply as "%s"">.
1549 =item Character following \%c must be '{' or a single-character Unicode property name in regex; marked by <-- HERE in m/%s/
1551 (F) (In the above the C<%c> is replaced by either C<p> or C<P>.) You
1552 specified something that isn't a legal Unicode property name. Most
1553 Unicode properties are specified by C<\p{...}>. But if the name is a
1554 single character one, the braces may be omitted.
1556 =item Character in 'C' format wrapped in pack
1562 where $x is either less than 0 or more than 255; the C<"C"> format is
1563 only for encoding native operating system characters (ASCII, EBCDIC,
1564 and so on) and not for Unicode characters, so Perl behaved as if you meant
1568 If you actually want to pack Unicode codepoints, use the C<"U"> format
1571 =item Character in 'c' format wrapped in pack
1577 where $x is either less than -128 or more than 127; the C<"c"> format
1578 is only for encoding native operating system characters (ASCII, EBCDIC,
1579 and so on) and not for Unicode characters, so Perl behaved as if you meant
1581 pack("c", $x & 255);
1583 If you actually want to pack Unicode codepoints, use the C<"U"> format
1586 =item Character in '%c' format wrapped in unpack
1588 (W unpack) You tried something like
1590 unpack("H", "\x{2a1}")
1592 where the format expects to process a byte (a character with a value
1593 below 256), but a higher value was provided instead. Perl uses the
1594 value modulus 256 instead, as if you had provided:
1596 unpack("H", "\x{a1}")
1598 =item Character in 'W' format wrapped in pack
1604 where $x is either less than 0 or more than 255. However, C<U0>-mode
1605 expects all values to fall in the interval [0, 255], so Perl behaved
1608 pack("U0W", $x & 255)
1610 =item Character(s) in '%c' format wrapped in pack
1612 (W pack) You tried something like
1614 pack("u", "\x{1f3}b")
1616 where the format expects to process a sequence of bytes (character with a
1617 value below 256), but some of the characters had a higher value. Perl
1618 uses the character values modulus 256 instead, as if you had provided:
1620 pack("u", "\x{f3}b")
1622 =item Character(s) in '%c' format wrapped in unpack
1624 (W unpack) You tried something like
1626 unpack("s", "\x{1f3}b")
1628 where the format expects to process a sequence of bytes (character with a
1629 value below 256), but some of the characters had a higher value. Perl
1630 uses the character values modulus 256 instead, as if you had provided:
1632 unpack("s", "\x{f3}b")
1634 =item charnames alias definitions may not contain a sequence of multiple spaces
1636 (F) You defined a character name which had multiple space characters
1637 in a row. Change them to single spaces. Usually these names are
1638 defined in the C<:alias> import argument to C<use charnames>, but they
1639 could be defined by a translator installed into C<$^H{charnames}>. See
1640 L<charnames/CUSTOM ALIASES>.
1642 =item charnames alias definitions may not contain trailing white-space
1644 (F) You defined a character name which ended in a space
1645 character. Remove the trailing space(s). Usually these names are
1646 defined in the C<:alias> import argument to C<use charnames>, but they
1647 could be defined by a translator installed into C<$^H{charnames}>.
1648 See L<charnames/CUSTOM ALIASES>.
1650 =item chdir() on unopened filehandle %s
1652 (W unopened) You tried chdir() on a filehandle that was never opened.
1654 =item "\c%c" is more clearly written simply as "%s"
1656 (W syntax) The C<\cI<X>> construct is intended to be a way to specify
1657 non-printable characters. You used it for a printable one, which
1658 is better written as simply itself, perhaps preceded by a backslash
1659 for non-word characters. Doing it the way you did is not portable
1660 between ASCII and EBCDIC platforms.
1662 =item Cloning substitution context is unimplemented
1664 (F) Creating a new thread inside the C<s///> operator is not supported.
1666 =item closedir() attempted on invalid dirhandle %s
1668 (W io) The dirhandle you tried to close is either closed or not really
1669 a dirhandle. Check your control flow.
1671 =item close() on unopened filehandle %s
1673 (W unopened) You tried to close a filehandle that was never opened.
1675 =item Closure prototype called
1677 (F) If a closure has attributes, the subroutine passed to an attribute
1678 handler is the prototype that is cloned when a new closure is created.
1679 This subroutine cannot be called.
1681 =item \C no longer supported in regex; marked by S<<-- HERE> in m/%s/
1683 (F) The \C character class used to allow a match of single byte
1684 within a multi-byte utf-8 character, but was removed in v5.24 as
1685 it broke encapsulation and its implementation was extremely buggy.
1686 If you really need to process the individual bytes, you probably
1687 want to convert your string to one where each underlying byte is
1688 stored as a character, with utf8::encode().
1690 =item Code missing after '/'
1692 (F) You had a (sub-)template that ends with a '/'. There must be
1693 another template code following the slash. See L<perlfunc/pack>.
1695 =item Code point 0x%X is not Unicode, and not portable
1697 (S non_unicode) You had a code point that has never been in any
1698 standard, so it is likely that languages other than Perl will NOT
1699 understand it. At one time, it was legal in some standards to have code
1700 points up to 0x7FFF_FFFF, but not higher, and this code point is higher.
1702 Acceptance of these code points is a Perl extension, and you should
1703 expect that nothing other than Perl can handle them; Perl itself on
1704 EBCDIC platforms before v5.24 does not handle them.
1706 Code points above 0xFFFF_FFFF require larger than a 32 bit word.
1708 Perl also makes no guarantees that the representation of these code
1709 points won't change at some point in the future, say when machines
1710 become available that have larger than a 64-bit word. At that time,
1711 files written by an older Perl would require conversion before being
1712 readable by a newer Perl.
1714 =item Code point 0x%X is not Unicode, may not be portable
1716 (S non_unicode) You had a code point above the Unicode maximum
1719 Perl allows strings to contain a superset of Unicode code points, but
1720 these may not be accepted by other languages/systems. Further, even if
1721 these languages/systems accept these large code points, they may have
1722 chosen a different representation for them than the UTF-8-like one that
1723 Perl has, which would mean files are not exchangeable between them and
1726 On EBCDIC platforms, code points above 0x3FFF_FFFF have a different
1727 representation in Perl v5.24 than before, so any file containing these
1728 that was written before that version will require conversion before
1729 being readable by a later Perl.
1731 =item %s: Command not found
1733 (A) You've accidentally run your script through B<csh> or another shell
1734 instead of Perl. Check the #! line, or manually feed your script into
1735 Perl yourself. The #! line at the top of your file could look like
1739 =item %s: command not found
1741 (A) You've accidentally run your script through B<bash> or another shell
1742 instead of Perl. Check the #! line, or manually feed your script into
1743 Perl yourself. The #! line at the top of your file could look like
1747 =item %s: command not found: %s
1749 (A) You've accidentally run your script through B<zsh> or another shell
1750 instead of Perl. Check the #! line, or manually feed your script into
1751 Perl yourself. The #! line at the top of your file could look like
1755 =item Compilation failed in require
1757 (F) Perl could not compile a file specified in a C<require> statement.
1758 Perl uses this generic message when none of the errors that it
1759 encountered were severe enough to halt compilation immediately.
1761 =item Complex regular subexpression recursion limit (%d) exceeded
1763 (W regexp) The regular expression engine uses recursion in complex
1764 situations where back-tracking is required. Recursion depth is limited
1765 to 32766, or perhaps less in architectures where the stack cannot grow
1766 arbitrarily. ("Simple" and "medium" situations are handled without
1767 recursion and are not subject to a limit.) Try shortening the string
1768 under examination; looping in Perl code (e.g. with C<while>) rather than
1769 in the regular expression engine; or rewriting the regular expression so
1770 that it is simpler or backtracks less. (See L<perlfaq2> for information
1771 on I<Mastering Regular Expressions>.)
1773 =item connect() on closed socket %s
1775 (W closed) You tried to do a connect on a closed socket. Did you forget
1776 to check the return value of your socket() call? See
1777 L<perlfunc/connect>.
1779 =item Constant(%s): Call to &{$^H{%s}} did not return a defined value
1781 (F) The subroutine registered to handle constant overloading
1782 (see L<overload>) or a custom charnames handler (see
1783 L<charnames/CUSTOM TRANSLATORS>) returned an undefined value.
1785 =item Constant(%s): $^H{%s} is not defined
1787 (F) The parser found inconsistencies while attempting to define an
1788 overloaded constant. Perhaps you forgot to load the corresponding
1791 =item Constant is not %s reference
1793 (F) A constant value (perhaps declared using the C<use constant> pragma)
1794 is being dereferenced, but it amounts to the wrong type of reference.
1795 The message indicates the type of reference that was expected. This
1796 usually indicates a syntax error in dereferencing the constant value.
1797 See L<perlsub/"Constant Functions"> and L<constant>.
1799 =item Constants from lexical variables potentially modified elsewhere are
1802 (D deprecated) You wrote something like
1805 $sub = sub () { $var };
1807 but $var is referenced elsewhere and could be modified after the C<sub>
1808 expression is evaluated. Either it is explicitly modified elsewhere
1809 (C<$var = 3>) or it is passed to a subroutine or to an operator like
1810 C<printf> or C<map>, which may or may not modify the variable.
1812 Traditionally, Perl has captured the value of the variable at that
1813 point and turned the subroutine into a constant eligible for inlining.
1814 In those cases where the variable can be modified elsewhere, this
1815 breaks the behavior of closures, in which the subroutine captures
1816 the variable itself, rather than its value, so future changes to the
1817 variable are reflected in the subroutine's return value.
1819 This usage is deprecated, because the behavior is likely to change
1820 in a future version of Perl.
1822 If you intended for the subroutine to be eligible for inlining, then
1823 make sure the variable is not referenced elsewhere, possibly by
1827 $sub = sub () { $var2 };
1829 If you do want this subroutine to be a closure that reflects future
1830 changes to the variable that it closes over, add an explicit C<return>:
1833 $sub = sub () { return $var };
1835 =item Constant subroutine %s redefined
1837 (W redefine)(S) You redefined a subroutine which had previously
1838 been eligible for inlining. See L<perlsub/"Constant Functions">
1839 for commentary and workarounds.
1841 =item Constant subroutine %s undefined
1843 (W misc) You undefined a subroutine which had previously been eligible
1844 for inlining. See L<perlsub/"Constant Functions"> for commentary and
1847 =item Constant(%s) unknown
1849 (F) The parser found inconsistencies either while attempting
1850 to define an overloaded constant, or when trying to find the
1851 character name specified in the C<\N{...}> escape. Perhaps you
1852 forgot to load the corresponding L<overload> pragma?
1854 =item :const is experimental
1856 (S experimental::const_attr) The "const" attribute is experimental.
1857 If you want to use the feature, disable the warning with C<no warnings
1858 'experimental::const_attr'>, but know that in doing so you are taking
1859 the risk that your code may break in a future Perl version.
1861 =item :const is not permitted on named subroutines
1863 (F) The "const" attribute causes an anonymous subroutine to be run and
1864 its value captured at the time that it is cloned. Named subroutines are
1865 not cloned like this, so the attribute does not make sense on them.
1867 =item Copy method did not return a reference
1869 (F) The method which overloads "=" is buggy. See
1870 L<overload/Copy Constructor>.
1872 =item &CORE::%s cannot be called directly
1874 (F) You tried to call a subroutine in the C<CORE::> namespace
1875 with C<&foo> syntax or through a reference. Some subroutines
1876 in this package cannot yet be called that way, but must be
1877 called as barewords. Something like this will work:
1879 BEGIN { *shove = \&CORE::push; }
1880 shove @array, 1,2,3; # pushes on to @array
1882 =item CORE::%s is not a keyword
1884 (F) The CORE:: namespace is reserved for Perl keywords.
1886 =item Corrupted regexp opcode %d > %d
1888 (P) This is either an error in Perl, or, if you're using
1889 one, your L<custom regular expression engine|perlreapi>. If not the
1890 latter, report the problem through the L<perlbug> utility.
1892 =item corrupted regexp pointers
1894 (P) The regular expression engine got confused by what the regular
1895 expression compiler gave it.
1897 =item corrupted regexp program
1899 (P) The regular expression engine got passed a regexp program without a
1902 =item Corrupt malloc ptr 0x%x at 0x%x
1904 (P) The malloc package that comes with Perl had an internal failure.
1906 =item Count after length/code in unpack
1908 (F) You had an unpack template indicating a counted-length string, but
1909 you have also specified an explicit size for the string. See
1912 =item Declaring references is experimental
1914 (S experimental::declared_refs) This warning is emitted if you use
1915 a reference constructor on the right-hand side of C<my>, C<state>, C<our>, or
1916 C<local>. Simply suppress the warning if you want to use the feature, but
1917 know that in doing so you are taking the risk of using an experimental
1918 feature which may change or be removed in a future Perl version:
1920 no warnings "experimental::declared_refs";
1921 use feature "declared_refs";
1925 The following are used in lib/diagnostics.t for testing two =items that
1926 share the same description. Changes here need to be propagated to there
1928 =item Deep recursion on anonymous subroutine
1930 =item Deep recursion on subroutine "%s"
1932 (W recursion) This subroutine has called itself (directly or indirectly)
1933 100 times more than it has returned. This probably indicates an
1934 infinite recursion, unless you're writing strange benchmark programs, in
1935 which case it indicates something else.
1937 This threshold can be changed from 100, by recompiling the F<perl> binary,
1938 setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1940 =item (?(DEFINE)....) does not allow branches in regex; marked by
1941 S<<-- HERE> in m/%s/
1943 (F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
1944 most likely cause of this error is that you left out a parenthesis inside
1945 of the C<....> part.
1947 The S<<-- HERE> shows whereabouts in the regular expression the problem was
1950 =item %s defines neither package nor VERSION--version check failed
1952 (F) You said something like "use Module 42" but in the Module file
1953 there are neither package declarations nor a C<$VERSION>.
1955 =item delete argument is index/value array slice, use array slice
1957 (F) You used index/value array slice syntax (C<%array[...]>) as
1958 the argument to C<delete>. You probably meant C<@array[...]> with
1959 an @ symbol instead.
1961 =item delete argument is key/value hash slice, use hash slice
1963 (F) You used key/value hash slice syntax (C<%hash{...}>) as the argument to
1964 C<delete>. You probably meant C<@hash{...}> with an @ symbol instead.
1966 =item delete argument is not a HASH or ARRAY element or slice
1968 (F) The argument to C<delete> must be either a hash or array element,
1974 or a hash or array slice, such as:
1976 @foo[$bar, $baz, $xyzzy]
1977 @{$ref->[12]}{"susie", "queue"}
1979 =item Delimiter for here document is too long
1981 (F) In a here document construct like C<<<FOO>, the label C<FOO> is too
1982 long for Perl to handle. You have to be seriously twisted to write code
1983 that triggers this error.
1985 =item Deprecated use of my() in false conditional
1987 (D deprecated) You used a declaration similar to C<my $x if 0>. There
1988 has been a long-standing bug in Perl that causes a lexical variable
1989 not to be cleared at scope exit when its declaration includes a false
1990 conditional. Some people have exploited this bug to achieve a kind of
1991 static variable. Since we intend to fix this bug, we don't want people
1992 relying on this behavior. You can achieve a similar static effect by
1993 declaring the variable in a separate block outside the function, eg
1995 sub f { my $x if 0; return $x++ }
1999 { my $x; sub f { return $x++ } }
2001 Beginning with perl 5.10.0, you can also use C<state> variables to have
2002 lexicals that are initialized only once (see L<feature>):
2004 sub f { state $x; return $x++ }
2006 =item DESTROY created new reference to dead object '%s'
2008 (F) A DESTROY() method created a new reference to the object which is
2009 just being DESTROYed. Perl is confused, and prefers to abort rather
2010 than to create a dangling reference.
2012 =item Did not produce a valid header
2016 =item %s did not return a true value
2018 (F) A required (or used) file must return a true value to indicate that
2019 it compiled correctly and ran its initialization code correctly. It's
2020 traditional to end such a file with a "1;", though any true value would
2021 do. See L<perlfunc/require>.
2023 =item (Did you mean &%s instead?)
2025 (W misc) You probably referred to an imported subroutine &FOO as $FOO or
2028 =item (Did you mean "local" instead of "our"?)
2030 (W misc) Remember that "our" does not localize the declared global
2031 variable. You have declared it again in the same lexical scope, which
2034 =item (Did you mean $ or @ instead of %?)
2036 (W) You probably said %hash{$key} when you meant $hash{$key} or
2037 @hash{@keys}. On the other hand, maybe you just meant %hash and got
2042 (F) You passed die() an empty string (the equivalent of C<die "">) or
2043 you called it with no args and C<$@> was empty.
2045 =item Document contains no data
2049 =item %s does not define %s::VERSION--version check failed
2051 (F) You said something like "use Module 42" but the Module did not
2052 define a C<$VERSION>.
2054 =item '/' does not take a repeat count
2056 (F) You cannot put a repeat count of any kind right after the '/' code.
2057 See L<perlfunc/pack>.
2059 =item Don't know how to get file name
2061 (P) C<PerlIO_getname>, a perl internal I/O function specific to VMS, was
2062 somehow called on another platform. This should not happen.
2064 =item Don't know how to handle magic of type \%o
2066 (P) The internal handling of magical variables has been cursed.
2068 =item do_study: out of memory
2070 (P) This should have been caught by safemalloc() instead.
2072 =item (Do you need to predeclare %s?)
2074 (S syntax) This is an educated guess made in conjunction with the message
2075 "%s found where operator expected". It often means a subroutine or module
2076 name is being referenced that hasn't been declared yet. This may be
2077 because of ordering problems in your file, or because of a missing
2078 "sub", "package", "require", or "use" statement. If you're referencing
2079 something that isn't defined yet, you don't actually have to define the
2080 subroutine or package before the current location. You can use an empty
2081 "sub foo;" or "package FOO;" to enter a "forward" declaration.
2083 =item dump() better written as CORE::dump()
2085 (W misc) You used the obsolescent C<dump()> built-in function, without fully
2086 qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
2088 =item dump is not supported
2090 (F) Your machine doesn't support dump/undump.
2092 =item Duplicate free() ignored
2094 (S malloc) An internal routine called free() on something that had
2097 =item Duplicate modifier '%c' after '%c' in %s
2099 (W unpack) You have applied the same modifier more than once after a
2100 type in a pack template. See L<perlfunc/pack>.
2102 =item elseif should be elsif
2104 (S syntax) There is no keyword "elseif" in Perl because Larry thinks
2105 it's ugly. Your code will be interpreted as an attempt to call a method
2106 named "elseif" for the class returned by the following block. This is
2107 unlikely to be what you want.
2109 =item Empty \%c in regex; marked by S<<-- HERE> in m/%s/
2111 =item Empty \%c{} in regex; marked by S<<-- HERE> in m/%s/
2113 (F) C<\p> and C<\P> are used to introduce a named Unicode property, as
2114 described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
2115 a regular expression without specifying the property name.
2117 =item ${^ENCODING} is no longer supported
2119 (D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
2120 the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
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 Execution 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 Filehandle %s opened only for input
2330 (W io) You tried to write on a read-only filehandle. If you intended
2331 it to be a read-write filehandle, you needed to open it with "+<" or
2332 "+>" or "+>>" instead of with "<" or nothing. If you intended only to
2333 write the file, use ">" or ">>". See L<perlfunc/open>.
2335 =item Filehandle %s opened only for output
2337 (W io) You tried to read from a filehandle opened only for writing, If
2338 you intended it to be a read/write filehandle, you needed to open it
2339 with "+<" or "+>" or "+>>" instead of with ">". If you intended only to
2340 read from the file, use "<". See L<perlfunc/open>. Another possibility
2341 is that you attempted to open filedescriptor 0 (also known as STDIN) for
2342 output (maybe you closed STDIN earlier?).
2344 =item Filehandle %s reopened as %s only for input
2346 (W io) You opened for reading a filehandle that got the same filehandle id
2347 as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR
2350 =item Filehandle STDIN reopened as %s only for output
2352 (W io) You opened for writing a filehandle that got the same filehandle id
2353 as STDIN. This occurred because you closed STDIN previously.
2355 =item Final $ should be \$ or $name
2357 (F) You must now decide whether the final $ in a string was meant to be
2358 a literal dollar sign, or was meant to introduce a variable name that
2359 happens to be missing. So you have to put either the backslash or the
2362 =item flock() on closed filehandle %s
2364 (W closed) The filehandle you're attempting to flock() got itself closed
2365 some time before now. Check your control flow. flock() operates on
2366 filehandles. Are you attempting to call flock() on a dirhandle by the
2369 =item Format not terminated
2371 (F) A format must be terminated by a line with a solitary dot. Perl got
2372 to the end of your file without finding such a line.
2374 =item Format %s redefined
2376 (W redefine) You redefined a format. To suppress this warning, say
2379 no warnings 'redefine';
2380 eval "format NAME =...";
2383 =item Found = in conditional, should be ==
2393 (or something like that).
2395 =item %s found where operator expected
2397 (S syntax) The Perl lexer knows whether to expect a term or an operator.
2398 If it sees what it knows to be a term when it was expecting to see an
2399 operator, it gives you this warning. Usually it indicates that an
2400 operator or delimiter was omitted, such as a semicolon.
2402 =item gdbm store returned %d, errno %d, key "%s"
2404 (S) A warning from the GDBM_File extension that a store failed.
2406 =item gethostent not implemented
2408 (F) Your C library apparently doesn't implement gethostent(), probably
2409 because if it did, it'd feel morally obligated to return every hostname
2412 =item get%sname() on closed socket %s
2414 (W closed) You tried to get a socket or peer socket name on a closed
2415 socket. Did you forget to check the return value of your socket() call?
2417 =item getpwnam returned invalid UIC %#o for user "%s"
2419 (S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
2420 C<getpwnam> operator returned an invalid UIC.
2422 =item getsockopt() on closed socket %s
2424 (W closed) You tried to get a socket option on a closed socket. Did you
2425 forget to check the return value of your socket() call? See
2426 L<perlfunc/getsockopt>.
2428 =item given is experimental
2430 (S experimental::smartmatch) C<given> depends on smartmatch, which
2431 is experimental, so its behavior may change or even be removed
2432 in any future release of perl. See the explanation under
2433 L<perlsyn/Experimental Details on given and when>.
2435 =item Global symbol "%s" requires explicit package name (did you forget to
2438 (F) You've said "use strict" or "use strict vars", which indicates
2439 that all variables must either be lexically scoped (using "my" or "state"),
2440 declared beforehand using "our", or explicitly qualified to say
2441 which package the global variable is in (using "::").
2443 =item glob failed (%s)
2445 (S glob) Something went wrong with the external program(s) used
2446 for C<glob> and C<< <*.c> >>. Usually, this means that you supplied a C<glob>
2447 pattern that caused the external program to fail and exit with a
2448 nonzero status. If the message indicates that the abnormal exit
2449 resulted in a coredump, this may also mean that your csh (C shell)
2450 is broken. If so, you should change all of the csh-related variables
2451 in config.sh: If you have tcsh, make the variables refer to it as
2452 if it were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them
2453 all empty (except that C<d_csh> should be C<'undef'>) so that Perl will
2454 think csh is missing. In either case, after editing config.sh, run
2455 C<./Configure -S> and rebuild Perl.
2457 =item Glob not terminated
2459 (F) The lexer saw a left angle bracket in a place where it was expecting
2460 a term, so it's looking for the corresponding right angle bracket, and
2461 not finding it. Chances are you left some needed parentheses out
2462 earlier in the line, and you really meant a "less than".
2464 =item gmtime(%f) failed
2466 (W overflow) You called C<gmtime> with a number that it could not handle:
2467 too large, too small, or NaN. The returned value is C<undef>.
2469 =item gmtime(%f) too large
2471 (W overflow) You called C<gmtime> with a number that was larger than
2472 it can reliably handle and C<gmtime> probably returned the wrong
2473 date. This warning is also triggered with NaN (the special
2474 not-a-number value).
2476 =item gmtime(%f) too small
2478 (W overflow) You called C<gmtime> with a number that was smaller than
2479 it can reliably handle and C<gmtime> probably returned the wrong date.
2481 =item Got an error from DosAllocMem
2483 (P) An error peculiar to OS/2. Most probably you're using an obsolete
2484 version of Perl, and this should not happen anyway.
2486 =item goto must have label
2488 (F) Unlike with "next" or "last", you're not allowed to goto an
2489 unspecified destination. See L<perlfunc/goto>.
2491 =item Goto undefined subroutine%s
2493 (F) You tried to call a subroutine with C<goto &sub> syntax, but
2494 the indicated subroutine hasn't been defined, or if it was, it
2495 has since been undefined.
2497 =item Group name must start with a non-digit word character in regex; marked by
2498 S<<-- HERE> in m/%s/
2500 (F) Group names must follow the rules for perl identifiers, meaning
2501 they must start with a non-digit word character. A common cause of
2502 this error is using (?&0) instead of (?0). See L<perlre>.
2504 =item ()-group starts with a count
2506 (F) A ()-group started with a count. A count is supposed to follow
2507 something: a template character or a ()-group. See L<perlfunc/pack>.
2509 =item %s had compilation errors.
2511 (F) The final summary message when a C<perl -c> fails.
2513 =item Had to create %s unexpectedly
2515 (S internal) A routine asked for a symbol from a symbol table that ought
2516 to have existed already, but for some reason it didn't, and had to be
2517 created on an emergency basis to prevent a core dump.
2519 =item %s has too many errors
2521 (F) The parser has given up trying to parse the program after 10 errors.
2522 Further error messages would likely be uninformative.
2524 =item Hexadecimal float: exponent overflow
2526 (W overflow) The hexadecimal floating point has a larger exponent
2527 than the floating point supports.
2529 =item Hexadecimal float: exponent underflow
2531 (W overflow) The hexadecimal floating point has a smaller exponent
2532 than the floating point supports.
2534 =item Hexadecimal float: internal error (%s)
2536 (F) Something went horribly bad in hexadecimal float handling.
2538 =item Hexadecimal float: mantissa overflow
2540 (W overflow) The hexadecimal floating point literal had more bits in
2541 the mantissa (the part between the 0x and the exponent, also known as
2542 the fraction or the significand) than the floating point supports.
2544 =item Hexadecimal float: precision loss
2546 (W overflow) The hexadecimal floating point had internally more
2547 digits than could be output. This can be caused by unsupported
2548 long double formats, or by 64-bit integers not being available
2549 (needed to retrieve the digits under some configurations).
2551 =item Hexadecimal float: unsupported long double format
2553 (F) You have configured Perl to use long doubles but
2554 the internals of the long double format are unknown;
2555 therefore the hexadecimal float output is impossible.
2557 =item Hexadecimal number > 0xffffffff non-portable
2559 (W portable) The hexadecimal number you specified is larger than 2**32-1
2560 (4294967295) and therefore non-portable between systems. See
2561 L<perlport> for more on portability concerns.
2563 =item Identifier too long
2565 (F) Perl limits identifiers (names for variables, functions, etc.) to
2566 about 250 characters for simple names, and somewhat more for compound
2567 names (like C<$A::B>). You've exceeded Perl's limits. Future versions
2568 of Perl are likely to eliminate these arbitrary limitations.
2570 =item Ignoring zero length \N{} in character class in regex; marked by
2571 S<<-- HERE> in m/%s/
2573 (W regexp) Named Unicode character escapes (C<\N{...}>) may return a
2574 zero-length sequence. When such an escape is used in a character
2575 class its behavior is not well defined. Check that the correct
2576 escape has been used, and the correct charname handler is in scope.
2578 =item Illegal binary digit %s
2580 (F) You used a digit other than 0 or 1 in a binary number.
2582 =item Illegal binary digit %s ignored
2584 (W digit) You may have tried to use a digit other than 0 or 1 in a
2585 binary number. Interpretation of the binary number stopped before the
2588 =item Illegal character after '_' in prototype for %s : %s
2590 (W illegalproto) An illegal character was found in a prototype
2591 declaration. The '_' in a prototype must be followed by a ';',
2592 indicating the rest of the parameters are optional, or one of '@'
2593 or '%', since those two will accept 0 or more final parameters.
2595 =item Illegal character \%o (carriage return)
2597 (F) Perl normally treats carriage returns in the program text as
2598 it would any other whitespace, which means you should never see
2599 this error when Perl was built using standard options. For some
2600 reason, your version of Perl appears to have been built without
2601 this support. Talk to your Perl administrator.
2603 =item Illegal character following sigil in a subroutine signature
2605 (F) A parameter in a subroutine signature contained an unexpected character
2606 following the C<$>, C<@> or C<%> sigil character. Normally the sigil
2607 should be followed by the variable name or C<=> etc. Perhaps you are
2608 trying use a prototype while in the scope of C<use feature 'signatures'>?
2611 sub foo ($$) {} # legal - a prototype
2613 use feature 'signatures;
2614 sub foo ($$) {} # illegal - was expecting a signature
2616 :prototype($$) {} # legal
2619 =item Illegal character in prototype for %s : %s
2621 (W illegalproto) An illegal character was found in a prototype declaration.
2622 Legal characters in prototypes are $, @, %, *, ;, [, ], &, \, and +.
2623 Perhaps you were trying to write a subroutine signature but didn't enable
2624 that feature first (C<use feature 'signatures'>), so your signature was
2625 instead interpreted as a bad prototype.
2627 =item Illegal declaration of anonymous subroutine
2629 (F) When using the C<sub> keyword to construct an anonymous subroutine,
2630 you must always specify a block of code. See L<perlsub>.
2632 =item Illegal declaration of subroutine %s
2634 (F) A subroutine was not declared correctly. See L<perlsub>.
2636 =item Illegal division by zero
2638 (F) You tried to divide a number by 0. Either something was wrong in
2639 your logic, or you need to put a conditional in to guard against
2642 =item Illegal hexadecimal digit %s ignored
2644 (W digit) You may have tried to use a character other than 0 - 9 or
2645 A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
2646 number stopped before the illegal character.
2648 =item Illegal modulus zero
2650 (F) You tried to divide a number by 0 to get the remainder. Most
2651 numbers don't take to this kindly.
2653 =item Illegal number of bits in vec
2655 (F) The number of bits in vec() (the third argument) must be a power of
2656 two from 1 to 32 (or 64, if your platform supports that).
2658 =item Illegal octal digit %s
2660 (F) You used an 8 or 9 in an octal number.
2662 =item Illegal octal digit %s ignored
2664 (W digit) You may have tried to use an 8 or 9 in an octal number.
2665 Interpretation of the octal number stopped before the 8 or 9.
2667 =item Illegal pattern in regex; marked by S<<-- HERE> in m/%s/
2669 (F) You wrote something like
2673 The C<"+"> is valid only when followed by digits, indicating a
2674 capturing group. See
2675 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
2677 =item Illegal suidscript
2679 (F) The script run under suidperl was somehow illegal.
2681 =item Illegal switch in PERL5OPT: -%c
2683 (X) The PERL5OPT environment variable may only be used to set the
2684 following switches: B<-[CDIMUdmtw]>.
2686 =item Illegal user-defined property name
2688 (F) You specified a Unicode-like property name in a regular expression
2689 pattern (using C<\p{}> or C<\P{}>) that Perl knows isn't an official
2690 Unicode property, and was likely meant to be a user-defined property
2691 name, but it can't be one of those, as they must begin with either C<In>
2692 or C<Is>. Check the spelling. See also
2693 L</Can't find Unicode property definition "%s">.
2695 =item Ill-formed CRTL environ value "%s"
2697 (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
2698 internal environ array, and encountered an element without the C<=>
2699 delimiter used to separate keys from values. The element is ignored.
2701 =item Ill-formed message in prime_env_iter: |%s|
2703 (W internal) A warning peculiar to VMS. Perl tried to read a logical
2704 name or CLI symbol definition when preparing to iterate over %ENV, and
2705 didn't see the expected delimiter between key and value, so the line was
2708 =item (in cleanup) %s
2710 (W misc) This prefix usually indicates that a DESTROY() method raised
2711 the indicated exception. Since destructors are usually called by the
2712 system at arbitrary points during execution, and often a vast number of
2713 times, the warning is issued only once for any number of failures that
2714 would otherwise result in the same message being repeated.
2716 Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
2717 also result in this warning. See L<perlcall/G_KEEPERR>.
2719 =item Incomplete expression within '(?[ ])' in regex; marked by S<<-- HERE>
2722 (F) There was a syntax error within the C<(?[ ])>. This can happen if the
2723 expression inside the construct was completely empty, or if there are
2724 too many or few operands for the number of operators. Perl is not smart
2725 enough to give you a more precise indication as to what is wrong.
2727 =item Inconsistent hierarchy during C3 merge of class '%s': merging failed on
2730 (F) The method resolution order (MRO) of the given class is not
2731 C3-consistent, and you have enabled the C3 MRO for this class. See the C3
2732 documentation in L<mro> for more information.
2734 =item Infinite recursion in regex
2736 (F) You used a pattern that references itself without consuming any input
2737 text. You should check the pattern to ensure that recursive patterns
2738 either consume text or fail.
2740 =item Initialization of state variables in list context currently forbidden
2742 (F) Currently the implementation of "state" only permits the
2743 initialization of scalar variables in scalar context. Re-write
2744 C<state ($a) = 42> as C<state $a = 42> to change from list to scalar
2745 context. Constructions such as C<state (@a) = foo()> will be
2746 supported in a future perl release.
2748 =item %%s[%s] in scalar context better written as $%s[%s]
2750 (W syntax) In scalar context, you've used an array index/value slice
2751 (indicated by %) to select a single element of an array. Generally
2752 it's better to ask for a scalar value (indicated by $). The difference
2753 is that C<$foo[&bar]> always behaves like a scalar, both in the value it
2754 returns and when evaluating its argument, while C<%foo[&bar]> provides
2755 a list context to its subscript, which can do weird things if you're
2756 expecting only one subscript. When called in list context, it also
2757 returns the index (what C<&bar> returns) in addition to the value.
2759 =item %%s{%s} in scalar context better written as $%s{%s}
2761 (W syntax) In scalar context, you've used a hash key/value slice
2762 (indicated by %) to select a single element of a hash. Generally it's
2763 better to ask for a scalar value (indicated by $). The difference
2764 is that C<$foo{&bar}> always behaves like a scalar, both in the value
2765 it returns and when evaluating its argument, while C<@foo{&bar}> and
2766 provides a list context to its subscript, which can do weird things
2767 if you're expecting only one subscript. When called in list context,
2768 it also returns the key in addition to the value.
2770 =item Insecure dependency in %s
2772 (F) You tried to do something that the tainting mechanism didn't like.
2773 The tainting mechanism is turned on when you're running setuid or
2774 setgid, or when you specify B<-T> to turn it on explicitly. The
2775 tainting mechanism labels all data that's derived directly or indirectly
2776 from the user, who is considered to be unworthy of your trust. If any
2777 such data is used in a "dangerous" operation, you get this error. See
2778 L<perlsec> for more information.
2780 =item Insecure directory in %s
2782 (F) You can't use system(), exec(), or a piped open in a setuid or
2783 setgid script if C<$ENV{PATH}> contains a directory that is writable by
2784 the world. Also, the PATH must not contain any relative directory.
2787 =item Insecure $ENV{%s} while running %s
2789 (F) You can't use system(), exec(), or a piped open in a setuid or
2790 setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
2791 C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
2792 supplied (or potentially supplied) by the user. The script must set
2793 the path to a known value, using trustworthy data. See L<perlsec>.
2795 =item Insecure user-defined property %s
2797 (F) Perl detected tainted data when trying to compile a regular
2798 expression that contains a call to a user-defined character property
2799 function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2800 See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
2802 =item Integer overflow in format string for %s
2804 (F) The indexes and widths specified in the format string of C<printf()>
2805 or C<sprintf()> are too large. The numbers must not overflow the size of
2806 integers for your architecture.
2808 =item Integer overflow in %s number
2810 (S overflow) The hexadecimal, octal or binary number you have specified
2811 either as a literal or as an argument to hex() or oct() is too big for
2812 your architecture, and has been converted to a floating point number.
2813 On a 32-bit architecture the largest hexadecimal, octal or binary number
2814 representable without overflow is 0xFFFFFFFF, 037777777777, or
2815 0b11111111111111111111111111111111 respectively. Note that Perl
2816 transparently promotes all numbers to a floating point representation
2817 internally--subject to loss of precision errors in subsequent
2820 =item Integer overflow in srand
2822 (S overflow) The number you have passed to srand is too big to fit
2823 in your architecture's integer representation. The number has been
2824 replaced with the largest integer supported (0xFFFFFFFF on 32-bit
2825 architectures). This means you may be getting less randomness than
2826 you expect, because different random seeds above the maximum will
2827 return the same sequence of random numbers.
2829 =item Integer overflow in version
2831 =item Integer overflow in version %d
2833 (W overflow) Some portion of a version initialization is too large for
2834 the size of integers for your architecture. This is not a warning
2835 because there is no rational reason for a version to try and use an
2836 element larger than typically 2**32. This is usually caused by trying
2837 to use some odd mathematical operation as a version, like 100/9.
2839 =item Internal disaster in regex; marked by S<<-- HERE> in m/%s/
2841 (P) Something went badly wrong in the regular expression parser.
2842 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2845 =item Internal inconsistency in tracking vforks
2847 (S) A warning peculiar to VMS. Perl keeps track of the number of times
2848 you've called C<fork> and C<exec>, to determine whether the current call
2849 to C<exec> should affect the current script or a subprocess (see
2850 L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
2851 Perl is making a guess and treating this C<exec> as a request to
2852 terminate the Perl script and execute the specified command.
2854 =item internal %<num>p might conflict with future printf extensions
2856 (S internal) Perl's internal routine that handles C<printf> and C<sprintf>
2857 formatting follows a slightly different set of rules when called from
2858 C or XS code. Specifically, formats consisting of digits followed
2859 by "p" (e.g., "%7p") are reserved for future use. If you see this
2860 message, then an XS module tried to call that routine with one such
2863 =item Internal urp in regex; marked by S<<-- HERE> in m/%s/
2865 (P) Something went badly awry in the regular expression parser. The
2866 S<<-- HERE> shows whereabouts in the regular expression the problem was
2869 =item %s (...) interpreted as function
2871 (W syntax) You've run afoul of the rule that says that any list operator
2872 followed by parentheses turns into a function, with all the list
2873 operators arguments found inside the parentheses. See
2874 L<perlop/Terms and List Operators (Leftward)>.
2876 =item In '(?...)', the '(' and '?' must be adjacent in regex;
2877 marked by S<<-- HERE> in m/%s/
2879 (F) The two-character sequence C<"(?"> in this context in a regular
2880 expression pattern should be an indivisible token, with nothing
2881 intervening between the C<"("> and the C<"?">, but you separated them
2884 =item Invalid %s attribute: %s
2886 (F) The indicated attribute for a subroutine or variable was not recognized
2887 by Perl or by a user-supplied handler. See L<attributes>.
2889 =item Invalid %s attributes: %s
2891 (F) The indicated attributes for a subroutine or variable were not
2892 recognized by Perl or by a user-supplied handler. See L<attributes>.
2894 =item Invalid character in charnames alias definition; marked by
2897 (F) You tried to create a custom alias for a character name, with
2898 the C<:alias> option to C<use charnames> and the specified character in
2899 the indicated name isn't valid. See L<charnames/CUSTOM ALIASES>.
2901 =item Invalid \0 character in %s for %s: %s\0%s
2903 (W syscalls) Embedded \0 characters in pathnames or other system call
2904 arguments produce a warning as of 5.20. The parts after the \0 were
2905 formerly ignored by system calls.
2907 =item Invalid character in \N{...}; marked by S<<-- HERE> in \N{%s}
2909 (F) Only certain characters are valid for character names. The
2910 indicated one isn't. See L<charnames/CUSTOM ALIASES>.
2912 =item Invalid conversion in %s: "%s"
2914 (W printf) Perl does not understand the given format conversion. See
2915 L<perlfunc/sprintf>.
2917 =item Invalid escape in the specified encoding in regex; marked by
2918 S<<-- HERE> in m/%s/
2920 (W regexp)(F) The numeric escape (for example C<\xHH>) of value < 256
2921 didn't correspond to a single character through the conversion
2922 from the encoding specified by the encoding pragma.
2923 The escape was replaced with REPLACEMENT CHARACTER (U+FFFD)
2924 instead, except within S<C<(?[ ])>>, where it is a fatal error.
2925 The S<<-- HERE> shows whereabouts in the regular expression the
2926 escape was discovered.
2928 =item Invalid hexadecimal number in \N{U+...}
2930 =item Invalid hexadecimal number in \N{U+...} in regex; marked by
2931 S<<-- HERE> in m/%s/
2933 (F) The character constant represented by C<...> is not a valid hexadecimal
2934 number. Either it is empty, or you tried to use a character other than
2935 0 - 9 or A - F, a - f in a hexadecimal number.
2937 =item Invalid module name %s with -%c option: contains single ':'
2939 (F) The module argument to perl's B<-m> and B<-M> command-line options
2940 cannot contain single colons in the module name, but only in the
2941 arguments after "=". In other words, B<-MFoo::Bar=:baz> is ok, but
2942 B<-MFoo:Bar=baz> is not.
2944 =item Invalid mro name: '%s'
2946 (F) You tried to C<mro::set_mro("classname", "foo")> or C<use mro 'foo'>,
2947 where C<foo> is not a valid method resolution order (MRO). Currently,
2948 the only valid ones supported are C<dfs> and C<c3>, unless you have loaded
2949 a module that is a MRO plugin. See L<mro> and L<perlmroapi>.
2951 =item Invalid negative number (%s) in chr
2953 (W utf8) You passed a negative number to C<chr>. Negative numbers are
2954 not valid character numbers, so it returns the Unicode replacement
2957 =item Invalid number '%s' for -C option.
2959 (F) You supplied a number to the -C option that either has extra leading
2960 zeroes or overflows perl's unsigned integer representation.
2962 =item invalid option -D%c, use -D'' to see choices
2964 (S debugging) Perl was called with invalid debugger flags. Call perl
2965 with the B<-D> option with no flags to see the list of acceptable values.
2966 See also L<perlrun/-Dletters>.
2968 =item Invalid quantifier in {,} in regex; marked by S<<-- HERE> in m/%s/
2970 (F) The pattern looks like a {min,max} quantifier, but the min or max
2971 could not be parsed as a valid number - either it has leading zeroes,
2972 or it represents too big a number to cope with. The S<<-- HERE> shows
2973 where in the regular expression the problem was discovered. See L<perlre>.
2975 =item Invalid [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2977 (F) The range specified in a character class had a minimum character
2978 greater than the maximum character. One possibility is that you forgot the
2979 C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
2980 up to C<ff>. The S<<-- HERE> shows whereabouts in the regular expression the
2981 problem was discovered. See L<perlre>.
2983 =item Invalid range "%s" in transliteration operator
2985 (F) The range specified in the tr/// or y/// operator had a minimum
2986 character greater than the maximum character. See L<perlop>.
2988 =item Invalid separator character %s in attribute list
2990 (F) Something other than a colon or whitespace was seen between the
2991 elements of an attribute list. If the previous attribute had a
2992 parenthesised parameter list, perhaps that list was terminated too soon.
2995 =item Invalid separator character %s in PerlIO layer specification %s
2997 (W layer) When pushing layers onto the Perl I/O system, something other
2998 than a colon or whitespace was seen between the elements of a layer list.
2999 If the previous attribute had a parenthesised parameter list, perhaps that
3000 list was terminated too soon.
3002 =item Invalid strict version format (%s)
3004 (F) A version number did not meet the "strict" criteria for versions.
3005 A "strict" version number is a positive decimal number (integer or
3006 decimal-fraction) without exponentiation or else a dotted-decimal
3007 v-string with a leading 'v' character and at least three components.
3008 The parenthesized text indicates which criteria were not met.
3009 See the L<version> module for more details on allowed version formats.
3011 =item Invalid type '%s' in %s
3013 (F) The given character is not a valid pack or unpack type.
3014 See L<perlfunc/pack>.
3016 (W) The given character is not a valid pack or unpack type but used to be
3019 =item Invalid version format (%s)
3021 (F) A version number did not meet the "lax" criteria for versions.
3022 A "lax" version number is a positive decimal number (integer or
3023 decimal-fraction) without exponentiation or else a dotted-decimal
3024 v-string. If the v-string has fewer than three components, it
3025 must have a leading 'v' character. Otherwise, the leading 'v' is
3026 optional. Both decimal and dotted-decimal versions may have a
3027 trailing "alpha" component separated by an underscore character
3028 after a fractional or dotted-decimal component. The parenthesized
3029 text indicates which criteria were not met. See the L<version> module
3030 for more details on allowed version formats.
3032 =item Invalid version object
3034 (F) The internal structure of the version object was invalid.
3035 Perhaps the internals were modified directly in some way or
3036 an arbitrary reference was blessed into the "version" class.
3038 =item In '(*VERB...)', the '(' and '*' must be adjacent in regex;
3039 marked by S<<-- HERE> in m/%s/
3041 (F) The two-character sequence C<"(*"> in
3042 this context in a regular expression pattern should be an
3043 indivisible token, with nothing intervening between the C<"(">
3044 and the C<"*">, but you separated them.
3046 =item ioctl is not implemented
3048 (F) Your machine apparently doesn't implement ioctl(), which is pretty
3049 strange for a machine that supports C.
3051 =item ioctl() on unopened %s
3053 (W unopened) You tried ioctl() on a filehandle that was never opened.
3054 Check your control flow and number of arguments.
3056 =item IO layers (like '%s') unavailable
3058 (F) Your Perl has not been configured to have PerlIO, and therefore
3059 you cannot use IO layers. To have PerlIO, Perl must be configured
3062 =item IO::Socket::atmark not implemented on this architecture
3064 (F) Your machine doesn't implement the sockatmark() functionality,
3065 neither as a system call nor an ioctl call (SIOCATMARK).
3067 =item '%s' is an unknown bound type in regex; marked by S<<-- HERE> in m/%s/
3069 (F) You used C<\b{...}> or C<\B{...}> and the C<...> is not known to
3070 Perl. The current valid ones are given in
3071 L<perlrebackslash/\b{}, \b, \B{}, \B>.
3073 =item %s() is deprecated on :utf8 handles
3075 (W deprecated) The sysread(), recv(), syswrite() and send() operators are
3076 deprecated on handles that have the C<:utf8> layer, either explicitly, or
3077 implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
3079 Both sysread() and recv() currently use only the C<:utf8> flag for the stream,
3080 ignoring the actual layers. Since sysread() and recv() do no UTF-8
3081 validation they can end up creating invalidly encoded scalars.
3083 Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise ignoring
3084 any layers. If the flag is set, both write the value UTF-8 encoded, even if
3085 the layer is some different encoding, such as the example above.
3087 Ideally, all of these operators would completely ignore the C<:utf8> state,
3088 working only with bytes, but this would result in silently breaking existing
3089 code. To avoid this a future version of perl will throw an exception when
3090 any of sysread(), recv(), syswrite() or send() are called on handle with the
3093 =item "%s" is more clearly written simply as "%s" in regex; marked by S<<-- HERE> in m/%s/
3095 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
3097 You specified a character that has the given plainer way of writing it,
3098 and which is also portable to platforms running with different character
3101 =item $* is no longer supported
3103 (D deprecated, syntax) The special variable C<$*>, deprecated in older
3104 perls, has been removed as of 5.10.0 and is no longer supported. In
3105 previous versions of perl the use of C<$*> enabled or disabled multi-line
3106 matching within a string.
3108 Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
3109 modifiers. You can enable C</m> for a lexical scope (even a whole file)
3110 with C<use re '/m'>. (In older versions: when C<$*> was set to a true value
3111 then all regular expressions behaved as if they were written using C</m>.)
3113 =item $# is no longer supported
3115 (D deprecated, syntax) The special variable C<$#>, deprecated in older
3116 perls, has been removed as of 5.10.0 and is no longer supported. You
3117 should use the printf/sprintf functions instead.
3119 =item '%s' is not a code reference
3121 (W overload) The second (fourth, sixth, ...) argument of
3122 overload::constant needs to be a code reference. Either
3123 an anonymous subroutine, or a reference to a subroutine.
3125 =item '%s' is not an overloadable type
3127 (W overload) You tried to overload a constant type the overload package is
3130 =item -i used with no filenames on the command line, reading from STDIN
3132 (S inplace) The C<-i> option was passed on the command line, indicating
3133 that the script is intended to edit files in place, but no files were
3134 given. This is usually a mistake, since editing STDIN in place doesn't
3135 make sense, and can be confusing because it can make perl look like
3136 it is hanging when it is really just trying to read from STDIN. You
3137 should either pass a filename to edit, or remove C<-i> from the command
3138 line. See L<perlrun> for more details.
3140 =item Junk on end of regexp in regex m/%s/
3142 (P) The regular expression parser is confused.
3144 =item Label not found for "last %s"
3146 (F) You named a loop to break out of, but you're not currently in a loop
3147 of that name, not even if you count where you were called from. See
3150 =item Label not found for "next %s"
3152 (F) You named a loop to continue, but you're not currently in a loop of
3153 that name, not even if you count where you were called from. See
3156 =item Label not found for "redo %s"
3158 (F) You named a loop to restart, but you're not currently in a loop of
3159 that name, not even if you count where you were called from. See
3162 =item leaving effective %s failed
3164 (F) While under the C<use filetest> pragma, switching the real and
3165 effective uids or gids failed.
3167 =item length/code after end of string in unpack
3169 (F) While unpacking, the string buffer was already used up when an unpack
3170 length/code combination tried to obtain more data. This results in
3171 an undefined value for the length. See L<perlfunc/pack>.
3173 =item length() used on %s (did you mean "scalar(%s)"?)
3175 (W syntax) You used length() on either an array or a hash when you
3176 probably wanted a count of the items.
3178 Array size can be obtained by doing:
3182 The number of items in a hash can be obtained by doing:
3186 =item Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
3188 (F) An extension is attempting to insert text into the current parse
3189 (using L<lex_stuff_pvn|perlapi/lex_stuff_pvn> or similar), but tried to insert a character that
3190 couldn't be part of the current input. This is an inherent pitfall
3191 of the stuffing mechanism, and one of the reasons to avoid it. Where
3192 it is necessary to stuff, stuffing only plain ASCII is recommended.
3194 =item Lexing code internal error (%s)
3196 (F) Lexing code supplied by an extension violated the lexer's API in a
3199 =item listen() on closed socket %s
3201 (W closed) You tried to do a listen on a closed socket. Did you forget
3202 to check the return value of your socket() call? See
3205 =item List form of piped open not implemented
3207 (F) On some platforms, notably Windows, the three-or-more-arguments
3208 form of C<open> does not support pipes, such as C<open($pipe, '|-', @args)>.
3209 Use the two-argument C<open($pipe, '|prog arg1 arg2...')> form instead.
3211 =item %s: loadable library and perl binaries are mismatched (got handshake key %p, needed %p)
3213 (P) A dynamic loading library C<.so> or C<.dll> was being loaded into the
3214 process that was built against a different build of perl than the
3215 said library was compiled against. Reinstalling the XS module will
3216 likely fix this error.
3218 =item Locale '%s' may not work well.%s
3220 (W locale) You are using the named locale, which is a non-UTF-8 one, and
3221 which perl has determined is not fully compatible with what it can
3222 handle. The second C<%s> gives a reason.
3224 By far the most common reason is that the locale has characters in it
3225 that are represented by more than one byte. The only such locales that
3226 Perl can handle are the UTF-8 locales. Most likely the specified locale
3227 is a non-UTF-8 one for an East Asian language such as Chinese or
3228 Japanese. If the locale is a superset of ASCII, the ASCII portion of it
3231 Some essentially obsolete locales that aren't supersets of ASCII, mainly
3232 those in ISO 646 or other 7-bit locales, such as ASMO 449, can also have
3233 problems, depending on what portions of the ASCII character set get
3234 changed by the locale and are also used by the program.
3235 The warning message lists the determinable conflicting characters.
3237 Note that not all incompatibilities are found.
3239 If this happens to you, there's not much you can do except switch to use a
3240 different locale or use L<Encode> to translate from the locale into
3241 UTF-8; if that's impracticable, you have been warned that some things
3244 This message is output once each time a bad locale is switched into
3245 within the scope of C<S<use locale>>, or on the first possibly-affected
3246 operation if the C<S<use locale>> inherits a bad one. It is not raised
3247 for any operations from the L<POSIX> module.
3249 =item localtime(%f) failed
3251 (W overflow) You called C<localtime> with a number that it could not handle:
3252 too large, too small, or NaN. The returned value is C<undef>.
3254 =item localtime(%f) too large
3256 (W overflow) You called C<localtime> with a number that was larger
3257 than it can reliably handle and C<localtime> probably returned the
3258 wrong date. This warning is also triggered with NaN (the special
3259 not-a-number value).
3261 =item localtime(%f) too small
3263 (W overflow) You called C<localtime> with a number that was smaller
3264 than it can reliably handle and C<localtime> probably returned the
3267 =item Lookbehind longer than %d not implemented in regex m/%s/
3269 (F) There is currently a limit on the length of string which lookbehind can
3270 handle. This restriction may be eased in a future release.
3272 =item Lost precision when %s %f by 1
3274 (W imprecision) The value you attempted to increment or decrement by one
3275 is too large for the underlying floating point representation to store
3276 accurately, hence the target of C<++> or C<--> is unchanged. Perl issues this
3277 warning because it has already switched from integers to floating point
3278 when values are too large for integers, and now even floating point is
3279 insufficient. You may wish to switch to using L<Math::BigInt> explicitly.
3281 =item lstat() on filehandle%s
3283 (W io) You tried to do an lstat on a filehandle. What did you mean
3284 by that? lstat() makes sense only on filenames. (Perl did a fstat()
3285 instead on the filehandle.)
3287 =item lvalue attribute %s already-defined subroutine
3289 (W misc) Although L<attributes.pm|attributes> allows this, turning the lvalue
3290 attribute on or off on a Perl subroutine that is already defined
3291 does not always work properly. It may or may not do what you
3292 want, depending on what code is inside the subroutine, with exact
3293 details subject to change between Perl versions. Only do this
3294 if you really know what you are doing.
3296 =item lvalue attribute ignored after the subroutine has been defined
3298 (W misc) Using the C<:lvalue> declarative syntax to make a Perl
3299 subroutine an lvalue subroutine after it has been defined is
3300 not permitted. To make the subroutine an lvalue subroutine,
3301 add the lvalue attribute to the definition, or put the C<sub
3302 foo :lvalue;> declaration before the definition.
3304 See also L<attributes.pm|attributes>.
3306 =item Magical list constants are not supported
3308 (F) You assigned a magical array to a stash element, and then tried
3309 to use the subroutine from the same slot. You are asking Perl to do
3310 something it cannot do, details subject to change between Perl versions.
3312 =item Malformed integer in [] in pack
3314 (F) Between the brackets enclosing a numeric repeat count only digits
3315 are permitted. See L<perlfunc/pack>.
3317 =item Malformed integer in [] in unpack
3319 (F) Between the brackets enclosing a numeric repeat count only digits
3320 are permitted. See L<perlfunc/pack>.
3322 =item Malformed PERLLIB_PREFIX
3324 (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
3331 with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
3332 a builtin library search path, prefix2 is substituted. The error may
3333 appear if components are not found, or are too long. See
3334 "PERLLIB_PREFIX" in L<perlos2>.
3336 =item Malformed prototype for %s: %s
3338 (F) You tried to use a function with a malformed prototype. The
3339 syntax of function prototypes is given a brief compile-time check for
3340 obvious errors like invalid characters. A more rigorous check is run
3341 when the function is called.
3342 Perhaps the function's author was trying to write a subroutine signature
3343 but didn't enable that feature first (C<use feature 'signatures'>),
3344 so the signature was instead interpreted as a bad prototype.
3346 =item Malformed UTF-8 character (%s)
3348 (S utf8)(F) Perl detected a string that didn't comply with UTF-8
3349 encoding rules, even though it had the UTF8 flag on.
3351 One possible cause is that you set the UTF8 flag yourself for data that
3352 you thought to be in UTF-8 but it wasn't (it was for example legacy
3353 8-bit data). To guard against this, you can use Encode::decode_utf8.
3355 If you use the C<:encoding(UTF-8)> PerlIO layer for input, invalid byte
3356 sequences are handled gracefully, but if you use C<:utf8>, the flag is
3357 set without validating the data, possibly resulting in this error
3360 See also L<Encode/"Handling Malformed Data">.
3362 =item Malformed UTF-8 character immediately after '%s'
3364 (F) You said C<use utf8>, but the program file doesn't comply with UTF-8
3365 encoding rules. The message prints out the properly encoded characters
3366 just before the first bad one. If C<utf8> warnings are enabled, a
3367 warning is generated that gives more details about the type of
3370 =item Malformed UTF-8 returned by \N{%s} immediately after '%s'
3372 (F) The charnames handler returned malformed UTF-8.
3374 =item Malformed UTF-8 string in '%c' format in unpack
3376 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3377 rules and perl was unable to guess how to make more progress.
3379 =item Malformed UTF-8 string in pack
3381 (F) You tried to pack something that didn't comply with UTF-8 encoding
3382 rules and perl was unable to guess how to make more progress.
3384 =item Malformed UTF-8 string in unpack
3386 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3387 rules and perl was unable to guess how to make more progress.
3389 =item Malformed UTF-16 surrogate
3391 (F) Perl thought it was reading UTF-16 encoded character data but while
3392 doing it Perl met a malformed Unicode surrogate.
3394 =item Mandatory parameter follows optional parameter
3396 (F) In a subroutine signature, you wrote something like "$a = undef,
3397 $b", making an earlier parameter optional and a later one mandatory.
3398 Parameters are filled from left to right, so it's impossible for the
3399 caller to omit an earlier one and pass a later one. If you want to act
3400 as if the parameters are filled from right to left, declare the rightmost
3401 optional and then shuffle the parameters around in the subroutine's body.
3403 =item Matched non-Unicode code point 0x%X against Unicode property; may
3406 (S non_unicode) Perl allows strings to contain a superset of
3407 Unicode code points; each code point may be as large as what is storable
3408 in an unsigned integer on your system, but these may not be accepted by
3409 other languages/systems. This message occurs when you matched a string
3410 containing such a code point against a regular expression pattern, and
3411 the code point was matched against a Unicode property, C<\p{...}> or
3412 C<\P{...}>. Unicode properties are only defined on Unicode code points,
3413 so the result of this match is undefined by Unicode, but Perl (starting
3414 in v5.20) treats non-Unicode code points as if they were typical
3415 unassigned Unicode ones, and matched this one accordingly. Whether a
3416 given property matches these code points or not is specified in
3417 L<perluniprops/Properties accessible through \p{} and \P{}>.
3419 This message is suppressed (unless it has been made fatal) if it is
3420 immaterial to the results of the match if the code point is Unicode or
3421 not. For example, the property C<\p{ASCII_Hex_Digit}> only can match
3422 the 22 characters C<[0-9A-Fa-f]>, so obviously all other code points,
3423 Unicode or not, won't match it. (And C<\P{ASCII_Hex_Digit}> will match
3424 every code point except these 22.)
3426 Getting this message indicates that the outcome of the match arguably
3427 should have been the opposite of what actually happened. If you think
3428 that is the case, you may wish to make the C<non_unicode> warnings
3429 category fatal; if you agree with Perl's decision, you may wish to turn
3432 See L<perlunicode/Beyond Unicode code points> for more information.
3434 =item %s matches null string many times in regex; marked by S<<-- HERE> in
3437 (W regexp) The pattern you've specified would be an infinite loop if the
3438 regular expression engine didn't specifically check for that. The S<<-- HERE>
3439 shows whereabouts in the regular expression the problem was discovered.
3442 =item Maximal count of pending signals (%u) exceeded
3444 (F) Perl aborted due to too high a number of signals pending. This
3445 usually indicates that your operating system tried to deliver signals
3446 too fast (with a very high priority), starving the perl process from
3447 resources it would need to reach a point where it can process signals
3448 safely. (See L<perlipc/"Deferred Signals (Safe Signals)">.)
3450 =item "%s" may clash with future reserved word
3452 (W) This warning may be due to running a perl5 script through a perl4
3453 interpreter, especially if the word that is being warned about is
3456 =item '%' may not be used in pack
3458 (F) You can't pack a string by supplying a checksum, because the
3459 checksumming process loses information, and you can't go the other way.
3460 See L<perlfunc/unpack>.
3462 =item Method for operation %s not found in package %s during blessing
3464 (F) An attempt was made to specify an entry in an overloading table that
3465 doesn't resolve to a valid subroutine. See L<overload>.
3467 =item Method %s not permitted
3471 =item Might be a runaway multi-line %s string starting on line %d
3473 (S) An advisory indicating that the previous error may have been caused
3474 by a missing delimiter on a string or pattern, because it eventually
3475 ended earlier on the current line.
3477 =item Misplaced _ in number
3479 (W syntax) An underscore (underbar) in a numeric constant did not
3480 separate two digits.
3482 =item Missing argument in %s
3484 (W missing) You called a function with fewer arguments than other
3485 arguments you supplied indicated would be needed.
3487 Currently only emitted when a printf-type format required more
3488 arguments than were supplied, but might be used in the future for
3489 other cases where we can statically determine that arguments to
3490 functions are missing, e.g. for the L<perlfunc/pack> function.
3492 =item Missing argument to -%c
3494 (F) The argument to the indicated command line switch must follow
3495 immediately after the switch, without intervening spaces.
3497 =item Missing braces on \N{}
3499 =item Missing braces on \N{} in regex; marked by S<<-- HERE> in m/%s/
3501 (F) Wrong syntax of character name literal C<\N{charname}> within
3502 double-quotish context. This can also happen when there is a space
3503 (or comment) between the C<\N> and the C<{> in a regex with the C</x> modifier.
3504 This modifier does not change the requirement that the brace immediately
3507 =item Missing braces on \o{}
3509 (F) A C<\o> must be followed immediately by a C<{> in double-quotish context.
3511 =item Missing comma after first argument to %s function
3513 (F) While certain functions allow you to specify a filehandle or an
3514 "indirect object" before the argument list, this ain't one of them.
3516 =item Missing command in piped open
3518 (W pipe) You used the C<open(FH, "| command")> or
3519 C<open(FH, "command |")> construction, but the command was missing or
3522 =item Missing control char name in \c
3524 (F) A double-quoted string ended with "\c", without the required control
3527 =item Missing ']' in prototype for %s : %s
3529 (W illegalproto) A grouping was started with C<[> but never closed with C<]>.
3531 =item Missing name in "%s sub"
3533 (F) The syntax for lexically scoped subroutines requires that
3534 they have a name with which they can be found.
3536 =item Missing $ on loop variable
3538 (F) Apparently you've been programming in B<csh> too much. Variables
3539 are always mentioned with the $ in Perl, unlike in the shells, where it
3540 can vary from one line to the next.
3542 =item (Missing operator before %s?)
3544 (S syntax) This is an educated guess made in conjunction with the message
3545 "%s found where operator expected". Often the missing operator is a comma.
3547 =item Missing or undefined argument to require
3549 (F) You tried to call require with no argument or with an undefined
3550 value as an argument. Require expects either a package name or a
3551 file-specification as an argument. See L<perlfunc/require>.
3553 =item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
3555 (F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
3557 =item Missing right brace on \N{}
3559 =item Missing right brace on \N{} or unescaped left brace after \N
3561 (F) C<\N> has two meanings.
3563 The traditional one has it followed by a name enclosed in braces,
3564 meaning the character (or sequence of characters) given by that
3565 name. Thus C<\N{ASTERISK}> is another way of writing C<*>, valid in both
3566 double-quoted strings and regular expression patterns. In patterns,
3567 it doesn't have the meaning an unescaped C<*> does.
3569 Starting in Perl 5.12.0, C<\N> also can have an additional meaning (only)
3570 in patterns, namely to match a non-newline character. (This is short
3571 for C<[^\n]>, and like C<.> but is not affected by the C</s> regex modifier.)
3573 This can lead to some ambiguities. When C<\N> is not followed immediately
3574 by a left brace, Perl assumes the C<[^\n]> meaning. Also, if the braces
3575 form a valid quantifier such as C<\N{3}> or C<\N{5,}>, Perl assumes that this
3576 means to match the given quantity of non-newlines (in these examples,
3577 3; and 5 or more, respectively). In all other case, where there is a
3578 C<\N{> and a matching C<}>, Perl assumes that a character name is desired.
3580 However, if there is no matching C<}>, Perl doesn't know if it was
3581 mistakenly omitted, or if C<[^\n]{> was desired, and raises this error.
3582 If you meant the former, add the right brace; if you meant the latter,
3583 escape the brace with a backslash, like so: C<\N\{>
3585 =item Missing right curly or square bracket
3587 (F) The lexer counted more opening curly or square brackets than closing
3588 ones. As a general rule, you'll find it's missing near the place you
3591 =item (Missing semicolon on previous line?)
3593 (S syntax) This is an educated guess made in conjunction with the message
3594 "%s found where operator expected". Don't automatically put a semicolon on
3595 the previous line just because you saw this message.
3597 =item Modification of a read-only value attempted
3599 (F) You tried, directly or indirectly, to change the value of a
3600 constant. You didn't, of course, try "2 = 1", because the compiler
3601 catches that. But an easy way to do the same thing is:
3603 sub mod { $_[0] = 1 }
3606 Another way is to assign to a substr() that's off the end of the string.
3608 Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
3609 is aliased to a constant in the look I<LIST>:
3612 foreach my $n ($x, 2) {
3613 $n *= 2; # modifies the $x, but fails on attempt to
3616 =item Modification of non-creatable array value attempted, %s
3618 (F) You tried to make an array value spring into existence, and the
3619 subscript was probably negative, even counting from end of the array
3622 =item Modification of non-creatable hash value attempted, %s
3624 (P) You tried to make a hash value spring into existence, and it
3625 couldn't be created for some peculiar reason.
3627 =item Module name must be constant
3629 (F) Only a bare module name is allowed as the first argument to a "use".
3631 =item Module name required with -%c option
3633 (F) The C<-M> or C<-m> options say that Perl should load some module, but
3634 you omitted the name of the module. Consult L<perlrun> for full details
3635 about C<-M> and C<-m>.
3637 =item More than one argument to '%s' open
3639 (F) The C<open> function has been asked to open multiple files. This
3640 can happen if you are trying to open a pipe to a command that takes a
3641 list of arguments, but have forgotten to specify a piped open mode.
3642 See L<perlfunc/open> for details.
3644 =item mprotect for COW string %p %u failed with %d
3646 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3647 L<perlguts/"Copy on Write">), but a shared string buffer
3648 could not be made read-only.
3650 =item mprotect for %p %u failed with %d
3652 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see L<perlhacktips>),
3653 but an op tree could not be made read-only.
3655 =item mprotect RW for COW string %p %u failed with %d
3657 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3658 L<perlguts/"Copy on Write">), but a read-only shared string
3659 buffer could not be made mutable.
3661 =item mprotect RW for %p %u failed with %d
3663 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see
3664 L<perlhacktips>), but a read-only op tree could not be made
3665 mutable before freeing the ops.
3667 =item msg%s not implemented
3669 (F) You don't have System V message IPC on your system.
3671 =item Multidimensional syntax %s not supported
3673 (W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
3674 They're written like C<$foo[1][2][3]>, as in C.
3676 =item Multiple slurpy parameters not allowed
3678 (F) In subroutine signatures, a slurpy parameter (C<@> or C<%>) must be
3679 the last parameter, and there must not be more than one of them; for
3682 sub foo ($a, @b) {} # legal
3683 sub foo ($a, @b, %) {} # invalid
3685 =item '/' must follow a numeric type in unpack
3687 (F) You had an unpack template that contained a '/', but this did not
3688 follow some unpack specification producing a numeric value.
3689 See L<perlfunc/pack>.
3691 =item %s must not be a named sequence in transliteration operator
3693 (F) Transliteration (C<tr///> and C<y///>) transliterates individual
3694 characters. But a named sequence by definition is more than an
3695 individual charater, and hence doing this operation on it doesn't make
3698 =item "my sub" not yet implemented
3700 (F) Lexically scoped subroutines are not yet implemented. Don't try
3703 =item "my" subroutine %s can't be in a package
3705 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
3706 sense to try to declare one with a package qualifier on the front.
3708 =item "my %s" used in sort comparison
3710 (W syntax) The package variables $a and $b are used for sort comparisons.
3711 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
3712 sort comparison block, and the variable had earlier been declared as a
3713 lexical variable. Either qualify the sort variable with the package
3714 name, or rename the lexical variable.
3716 =item "my" variable %s can't be in a package
3718 (F) Lexically scoped variables aren't in a package, so it doesn't make
3719 sense to try to declare one with a package qualifier on the front. Use
3720 local() if you want to localize a package variable.
3722 =item Name "%s::%s" used only once: possible typo
3724 (W once) Typographical errors often show up as unique variable
3725 names. If you had a good reason for having a unique name, then
3726 just mention it again somehow to suppress the message. The C<our>
3727 declaration is also provided for this purpose.
3729 NOTE: This warning detects package symbols that have been used
3730 only once. This means lexical variables will never trigger this
3731 warning. It also means that all of the package variables $c, @c,
3732 %c, as well as *c, &c, sub c{}, c(), and c (the filehandle or
3733 format) are considered the same; if a program uses $c only once
3734 but also uses any of the others it will not trigger this warning.
3735 Symbols beginning with an underscore and symbols using special
3736 identifiers (q.v. L<perldata>) are exempt from this warning.
3738 =item Need exactly 3 octal digits in regex; marked by S<<-- HERE> in m/%s/
3740 (F) Within S<C<(?[ ])>>, all constants interpreted as octal need to be
3741 exactly 3 digits long. This helps catch some ambiguities. If your
3742 constant is too short, add leading zeros, like
3744 (?[ [ \078 ] ]) # Syntax error!
3745 (?[ [ \0078 ] ]) # Works
3746 (?[ [ \007 8 ] ]) # Clearer
3748 The maximum number this construct can express is C<\777>. If you
3749 need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes> instead. If you meant
3750 two separate things, you need to separate them:
3752 (?[ [ \7776 ] ]) # Syntax error!
3753 (?[ [ \o{7776} ] ]) # One meaning
3754 (?[ [ \777 6 ] ]) # Another meaning
3755 (?[ [ \777 \006 ] ]) # Still another
3757 =item Negative '/' count in unpack
3759 (F) The length count obtained from a length/code unpack operation was
3760 negative. See L<perlfunc/pack>.
3762 =item Negative length
3764 (F) You tried to do a read/write/send/recv operation with a buffer
3765 length that is less than 0. This is difficult to imagine.
3767 =item Negative offset to vec in lvalue context
3769 (F) When C<vec> is called in an lvalue context, the second argument must be
3770 greater than or equal to zero.
3772 =item Negative repeat count does nothing
3774 (W numeric) You tried to execute the
3775 L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
3776 times, which doesn't make sense.
3778 =item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
3780 (F) You can't quantify a quantifier without intervening parentheses.
3781 So things like ** or +* or ?* are illegal. The S<<-- HERE> shows
3782 whereabouts in the regular expression the problem was discovered.
3784 Note that the minimal matching quantifiers, C<*?>, C<+?>, and
3785 C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
3787 =item %s never introduced
3789 (S internal) The symbol in question was declared but somehow went out of
3790 scope before it could possibly have been used.
3792 =item next::method/next::can/maybe::next::method cannot find enclosing method
3794 (F) C<next::method> needs to be called within the context of a
3795 real method in a real package, and it could not find such a context.
3798 =item \N in a character class must be a named character: \N{...} in regex;
3799 marked by S<<-- HERE> in m/%s/
3801 (F) The new (as of Perl 5.12) meaning of C<\N> as C<[^\n]> is not valid in a
3802 bracketed character class, for the same reason that C<.> in a character
3803 class loses its specialness: it matches almost everything, which is
3804 probably not what you want.
3806 =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/
3808 (F) Named Unicode character escapes (C<\N{...}>) may return a
3809 multi-character sequence. Even though a character class is
3810 supposed to match just one character of input, perl will match the
3811 whole thing correctly, except when the class is inverted (C<[^...]>),
3812 or the escape is the beginning or final end point of a range. The
3813 mathematically logical behavior for what matches when inverting
3814 is very different from what people expect, so we have decided to
3815 forbid it. Similarly unclear is what should be generated when the
3816 C<\N{...}> is used as one of the end points of the range, such as in
3818 [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]
3820 What is meant here is unclear, as the C<\N{...}> escape is a sequence
3821 of code points, so this is made an error.
3823 =item \N{NAME} must be resolved by the lexer in regex; marked by
3824 S<<-- HERE> in m/%s/
3826 (F) When compiling a regex pattern, an unresolved named character or
3827 sequence was encountered. This can happen in any of several ways that
3828 bypass the lexer, such as using single-quotish context, or an extra
3829 backslash in double-quotish:
3831 $re = '\N{SPACE}'; # Wrong!
3832 $re = "\\N{SPACE}"; # Wrong!
3835 Instead, use double-quotes with a single backslash:
3837 $re = "\N{SPACE}"; # ok
3840 The lexer can be bypassed as well by creating the pattern from smaller
3844 /${re}{SPACE}/; # Wrong!
3846 It's not a good idea to split a construct in the middle like this, and
3847 it doesn't work here. Instead use the solution above.
3849 Finally, the message also can happen under the C</x> regex modifier when the
3850 C<\N> is separated by spaces from the C<{>, in which case, remove the spaces.
3852 /\N {SPACE}/x; # Wrong!
3855 =item No %s allowed while running setuid
3857 (F) Certain operations are deemed to be too insecure for a setuid or
3858 setgid script to even be allowed to attempt. Generally speaking there
3859 will be another way to do what you want that is, if not secure, at least
3860 securable. See L<perlsec>.
3862 =item No code specified for -%c
3864 (F) Perl's B<-e> and B<-E> command-line options require an argument. If
3865 you want to run an empty program, pass the empty string as a separate
3866 argument or run a program consisting of a single 0 or 1:
3872 =item No comma allowed after %s
3874 (F) A list operator that has a filehandle or "indirect object" is
3875 not allowed to have a comma between that and the following arguments.
3876 Otherwise it'd be just another one of the arguments.
3878 One possible cause for this is that you expected to have imported
3879 a constant to your name space with B<use> or B<import> while no such
3880 importing took place, it may for example be that your operating
3881 system does not support that particular constant. Hopefully you did
3882 use an explicit import list for the constants you expect to see;
3883 please see L<perlfunc/use> and L<perlfunc/import>. While an
3884 explicit import list would probably have caught this error earlier
3885 it naturally does not remedy the fact that your operating system
3886 still does not support that constant. Maybe you have a typo in
3887 the constants of the symbol import list of B<use> or B<import> or in the
3888 constant name at the line where this error was triggered?
3890 =item No command into which to pipe on command line
3892 (F) An error peculiar to VMS. Perl handles its own command line
3893 redirection, and found a '|' at the end of the command line, so it
3894 doesn't know where you want to pipe the output from this command.
3896 =item No DB::DB routine defined
3898 (F) The currently executing code was compiled with the B<-d> switch, but
3899 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3900 module) didn't define a routine to be called at the beginning of each
3903 =item No dbm on this machine
3905 (P) This is counted as an internal error, because every machine should
3906 supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
3908 =item No DB::sub routine defined
3910 (F) The currently executing code was compiled with the B<-d> switch, but
3911 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3912 module) didn't define a C<DB::sub> routine to be called at the beginning
3913 of each ordinary subroutine call.
3915 =item No directory specified for -I
3917 (F) The B<-I> command-line switch requires a directory name as part of the
3918 I<same> argument. Use B<-Ilib>, for instance. B<-I lib> won't work.
3920 =item No error file after 2> or 2>> on command line
3922 (F) An error peculiar to VMS. Perl handles its own command line
3923 redirection, and found a '2>' or a '2>>' on the command line, but can't
3924 find the name of the file to which to write data destined for stderr.
3926 =item No group ending character '%c' found in template
3928 (F) A pack or unpack template has an opening '(' or '[' without its
3929 matching counterpart. See L<perlfunc/pack>.
3931 =item No input file after < on command line
3933 (F) An error peculiar to VMS. Perl handles its own command line
3934 redirection, and found a '<' on the command line, but can't find the
3935 name of the file from which to read data for stdin.
3937 =item No next::method '%s' found for %s
3939 (F) C<next::method> found no further instances of this method name
3940 in the remaining packages of the MRO of this class. If you don't want
3941 it throwing an exception, use C<maybe::next::method>
3942 or C<next::can>. See L<mro>.
3944 =item Non-finite repeat count does nothing
3946 (W numeric) You tried to execute the
3947 L<C<x>|perlop/Multiplicative Operators> repetition operator C<Inf> (or
3948 C<-Inf>) or C<NaN> times, which doesn't make sense.
3950 =item Non-hex character in regex; marked by S<<-- HERE> in m/%s/
3952 (F) In a regular expression, there was a non-hexadecimal character where
3953 a hex one was expected, like
3958 =item Non-octal character in regex; marked by S<<-- HERE> in m/%s/
3960 (F) In a regular expression, there was a non-octal character where
3961 an octal one was expected, like
3965 =item Non-octal character '%c'. Resolved as "%s"
3967 (W digit) In parsing an octal numeric constant, a character was
3968 unexpectedly encountered that isn't octal. The resulting value
3971 =item "no" not allowed in expression
3973 (F) The "no" keyword is recognized and executed at compile time, and
3974 returns no useful value. See L<perlmod>.
3976 =item Non-string passed as bitmask
3978 (W misc) A number has been passed as a bitmask argument to select().
3979 Use the vec() function to construct the file descriptor bitmasks for
3980 select. See L<perlfunc/select>.
3982 =item No output file after > on command line
3984 (F) An error peculiar to VMS. Perl handles its own command line
3985 redirection, and found a lone '>' at the end of the command line, so it
3986 doesn't know where you wanted to redirect stdout.
3988 =item No output file after > or >> on command line
3990 (F) An error peculiar to VMS. Perl handles its own command line
3991 redirection, and found a '>' or a '>>' on the command line, but can't
3992 find the name of the file to which to write data destined for stdout.
3994 =item No package name allowed for variable %s in "our"
3996 (F) Fully qualified variable names are not allowed in "our"
3997 declarations, because that doesn't make much sense under existing
3998 rules. Such syntax is reserved for future extensions.
4000 =item No Perl script found in input
4002 (F) You called C<perl -x>, but no line was found in the file beginning
4003 with #! and containing the word "perl".
4005 =item No setregid available
4007 (F) Configure didn't find anything resembling the setregid() call for
4010 =item No setreuid available
4012 (F) Configure didn't find anything resembling the setreuid() call for
4015 =item No such class %s
4017 (F) You provided a class qualifier in a "my", "our" or "state"
4018 declaration, but this class doesn't exist at this point in your program.
4020 =item No such class field "%s" in variable %s of type %s
4022 (F) You tried to access a key from a hash through the indicated typed
4023 variable but that key is not allowed by the package of the same type.
4024 The indicated package has restricted the set of allowed keys using the
4027 =item No such hook: %s
4029 (F) You specified a signal hook that was not recognized by Perl.
4030 Currently, Perl accepts C<__DIE__> and C<__WARN__> as valid signal hooks.
4032 =item No such pipe open
4034 (P) An error peculiar to VMS. The internal routine my_pclose() tried to
4035 close a pipe which hadn't been opened. This should have been caught
4036 earlier as an attempt to close an unopened filehandle.
4038 =item No such signal: SIG%s
4040 (W signal) You specified a signal name as a subscript to %SIG that was
4041 not recognized. Say C<kill -l> in your shell to see the valid signal
4042 names on your system.
4044 =item Not a CODE reference
4046 (F) Perl was trying to evaluate a reference to a code value (that is, a
4047 subroutine), but found a reference to something else instead. You can
4048 use the ref() function to find out what kind of ref it really was. See
4051 =item Not a GLOB reference
4053 (F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
4054 symbol table entry that looks like C<*foo>), but found a reference to
4055 something else instead. You can use the ref() function to find out what
4056 kind of ref it really was. See L<perlref>.
4058 =item Not a HASH reference
4060 (F) Perl was trying to evaluate a reference to a hash value, but found a
4061 reference to something else instead. You can use the ref() function to
4062 find out what kind of ref it really was. See L<perlref>.
4064 =item '#' not allowed immediately following a sigil in a subroutine signature
4066 (F) In a subroutine signature definition, a comment following a sigil
4067 (C<$>, C<@> or C<%>), needs to be separated by whitespace or a commma etc., in
4068 particular to avoid confusion with the C<$#> variable. For example:
4071 sub f ($# ignore first arg
4074 sub f ($, # ignore first arg
4077 =item Not an ARRAY reference
4079 (F) Perl was trying to evaluate a reference to an array value, but found
4080 a reference to something else instead. You can use the ref() function
4081 to find out what kind of ref it really was. See L<perlref>.
4083 =item Not a SCALAR reference
4085 (F) Perl was trying to evaluate a reference to a scalar value, but found
4086 a reference to something else instead. You can use the ref() function
4087 to find out what kind of ref it really was. See L<perlref>.
4089 =item Not a subroutine reference
4091 (F) Perl was trying to evaluate a reference to a code value (that is, a
4092 subroutine), but found a reference to something else instead. You can
4093 use the ref() function to find out what kind of ref it really was. See
4096 =item Not a subroutine reference in overload table
4098 (F) An attempt was made to specify an entry in an overloading table that
4099 doesn't somehow point to a valid subroutine. See L<overload>.
4101 =item Not enough arguments for %s
4103 (F) The function requires more arguments than you specified.
4105 =item Not enough format arguments
4107 (W syntax) A format specified more picture fields than the next line
4108 supplied. See L<perlform>.
4112 (A) You've accidentally run your script through the Bourne shell instead
4113 of Perl. Check the #! line, or manually feed your script into Perl
4116 =item (?[...]) not valid in locale in regex; marked by S<<-- HERE> in m/%s/
4118 (F) C<(?[...])> cannot be used within the scope of a C<S<use locale>> or with
4119 an C</l> regular expression modifier, as that would require deferring
4120 to run-time the calculation of what it should evaluate to, and it is
4121 regex compile-time only.
4123 =item no UTC offset information; assuming local time is UTC
4125 (S) A warning peculiar to VMS. Perl was unable to find the local
4126 timezone offset, so it's assuming that local system time is equivalent
4127 to UTC. If it's not, define the logical name
4128 F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
4129 need to be added to UTC to get local time.
4131 =item NULL OP IN RUN
4133 (S debugging) Some internal routine called run() with a null opcode
4136 =item Null picture in formline
4138 (F) The first argument to formline must be a valid format picture
4139 specification. It was found to be empty, which probably means you
4140 supplied it an uninitialized value. See L<perlform>.
4144 (P) An attempt was made to realloc NULL.
4146 =item NULL regexp argument
4148 (P) The internal pattern matching routines blew it big time.
4150 =item NULL regexp parameter
4152 (P) The internal pattern matching routines are out of their gourd.
4154 =item Number too long
4156 (F) Perl limits the representation of decimal numbers in programs to
4157 about 250 characters. You've exceeded that length. Future
4158 versions of Perl are likely to eliminate this arbitrary limitation. In
4159 the meantime, try using scientific notation (e.g. "1e6" instead of
4162 =item Number with no digits
4164 (F) Perl was looking for a number but found nothing that looked like
4165 a number. This happens, for example with C<\o{}>, with no number between
4168 =item Octal number > 037777777777 non-portable
4170 (W portable) The octal number you specified is larger than 2**32-1
4171 (4294967295) and therefore non-portable between systems. See
4172 L<perlport> for more on portability concerns.
4174 =item Odd name/value argument for subroutine
4176 (F) A subroutine using a slurpy hash parameter in its signature
4177 received an odd number of arguments to populate the hash. It requires
4178 the arguments to be paired, with the same number of keys as values.
4179 The caller of the subroutine is presumably at fault. Inconveniently,
4180 this error will be reported at the location of the subroutine, not that
4183 =item Odd number of arguments for overload::constant
4185 (W overload) The call to overload::constant contained an odd number of
4186 arguments. The arguments should come in pairs.
4188 =item Odd number of elements in anonymous hash
4190 (W misc) You specified an odd number of elements to initialize a hash,
4191 which is odd, because hashes come in key/value pairs.
4193 =item Odd number of elements in hash assignment
4195 (W misc) You specified an odd number of elements to initialize a hash,
4196 which is odd, because hashes come in key/value pairs.
4198 =item Offset outside string
4200 (F)(W layer) You tried to do a read/write/send/recv/seek operation
4201 with an offset pointing outside the buffer. This is difficult to
4202 imagine. The sole exceptions to this are that zero padding will
4203 take place when going past the end of the string when either
4204 C<sysread()>ing a file, or when seeking past the end of a scalar opened
4205 for I/O (in anticipation of future reads and to imitate the behavior
4208 =item Only one /x regex modifier is allowed
4210 =item Only one /x regex modifier is allowed in regex; marked by <-- HERE in m/%s/
4212 (F) You used the C</x> regular expression pattern modifier at least twice in a
4213 string of modifiers. This has been made illegal, in order to allow future
4214 extensions to the Perl language.
4216 =item %s() on unopened %s
4218 (W unopened) An I/O operation was attempted on a filehandle that was
4219 never initialized. You need to do an open(), a sysopen(), or a socket()
4220 call, or call a constructor from the FileHandle package.
4222 =item -%s on unopened filehandle %s
4224 (W unopened) You tried to invoke a file test operator on a filehandle
4225 that isn't open. Check your control flow. See also L<perlfunc/-X>.
4229 (S internal) An internal warning that the grammar is screwed up.
4233 (S internal) An internal warning that the grammar is screwed up.
4235 =item Opening dirhandle %s also as a file
4237 (D io, deprecated) You used open() to associate a filehandle to
4238 a symbol (glob or scalar) that already holds a dirhandle.
4239 Although legal, this idiom might render your code confusing
4242 =item Opening filehandle %s also as a directory
4244 (D io, deprecated) You used opendir() to associate a dirhandle to
4245 a symbol (glob or scalar) that already holds a filehandle.
4246 Although legal, this idiom might render your code confusing
4249 =item Operand with no preceding operator in regex; marked by S<<-- HERE> in
4252 (F) You wrote something like
4254 (?[ \p{Digit} \p{Thai} ])
4256 There are two operands, but no operator giving how you want to combine
4259 =item Operation "%s": no method found, %s
4261 (F) An attempt was made to perform an overloaded operation for which no
4262 handler was defined. While some handlers can be autogenerated in terms
4263 of other handlers, there is no default handler for any operation, unless
4264 the C<fallback> overloading key is specified to be true. See L<overload>.
4266 =item Operation "%s" returns its argument for non-Unicode code point 0x%X
4268 (S non_unicode) You performed an operation requiring Unicode rules
4269 on a code point that is not in Unicode, so what it should do is not
4270 defined. Perl has chosen to have it do nothing, and warn you.
4272 If the operation shown is "ToFold", it means that case-insensitive
4273 matching in a regular expression was done on the code point.
4275 If you know what you are doing you can turn off this warning by
4276 C<no warnings 'non_unicode';>.
4278 =item Operation "%s" returns its argument for UTF-16 surrogate U+%X
4280 (S surrogate) You performed an operation requiring Unicode
4281 rules on a Unicode surrogate. Unicode frowns upon the use
4282 of surrogates for anything but storing strings in UTF-16, but
4283 rules are (reluctantly) defined for the surrogates, and
4284 they are to do nothing for this operation. Because the use of
4285 surrogates can be dangerous, Perl warns.
4287 If the operation shown is "ToFold", it means that case-insensitive
4288 matching in a regular expression was done on the code point.
4290 If you know what you are doing you can turn off this warning by
4291 C<no warnings 'surrogate';>.
4293 =item Operator or semicolon missing before %s
4295 (S ambiguous) You used a variable or subroutine call where the parser
4296 was expecting an operator. The parser has assumed you really meant to
4297 use an operator, but this is highly likely to be incorrect. For
4298 example, if you say "*foo *foo" it will be interpreted as if you said
4301 =item Optional parameter lacks default expression
4303 (F) In a subroutine signature, you wrote something like "$a =", making a
4304 named optional parameter without a default value. A nameless optional
4305 parameter is permitted to have no default value, but a named one must
4306 have a specific default. You probably want "$a = undef".
4308 =item "our" variable %s redeclared
4310 (W misc) You seem to have already declared the same global once before
4311 in the current lexical scope.
4313 =item Out of memory!
4315 (X) The malloc() function returned 0, indicating there was insufficient
4316 remaining memory (or virtual memory) to satisfy the request. Perl has
4317 no option but to exit immediately.
4319 At least in Unix you may be able to get past this by increasing your
4320 process datasize limits: in csh/tcsh use C<limit> and
4321 C<limit datasize n> (where C<n> is the number of kilobytes) to check
4322 the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
4323 and C<ulimit -d n>, respectively.
4325 =item Out of memory during %s extend
4327 (X) An attempt was made to extend an array, a list, or a string beyond
4328 the largest possible memory allocation.
4330 =item Out of memory during "large" request for %s
4332 (F) The malloc() function returned 0, indicating there was insufficient
4333 remaining memory (or virtual memory) to satisfy the request. However,
4334 the request was judged large enough (compile-time default is 64K), so a
4335 possibility to shut down by trapping this error is granted.
4337 =item Out of memory during request for %s
4339 (X)(F) The malloc() function returned 0, indicating there was
4340 insufficient remaining memory (or virtual memory) to satisfy the
4343 The request was judged to be small, so the possibility to trap it
4344 depends on the way perl was compiled. By default it is not trappable.
4345 However, if compiled for this, Perl may use the contents of C<$^M> as an
4346 emergency pool after die()ing with this message. In this case the error
4347 is trappable I<once>, and the error message will include the line and file
4348 where the failed request happened.
4350 =item Out of memory during ridiculously large request
4352 (F) You can't allocate more than 2^31+"small amount" bytes. This error
4353 is most likely to be caused by a typo in the Perl program. e.g.,
4354 C<$arr[time]> instead of C<$arr[$time]>.
4356 =item Out of memory for yacc stack
4358 (F) The yacc parser wanted to grow its stack so it could continue
4359 parsing, but realloc() wouldn't give it more memory, virtual or
4362 =item '.' outside of string in pack
4364 (F) The argument to a '.' in your template tried to move the working
4365 position to before the start of the packed string being built.
4367 =item '@' outside of string in unpack
4369 (F) You had a template that specified an absolute position outside
4370 the string being unpacked. See L<perlfunc/pack>.
4372 =item '@' outside of string with malformed UTF-8 in unpack
4374 (F) You had a template that specified an absolute position outside
4375 the string being unpacked. The string being unpacked was also invalid
4376 UTF-8. See L<perlfunc/pack>.
4378 =item overload arg '%s' is invalid
4380 (W overload) The L<overload> pragma was passed an argument it did not
4381 recognize. Did you mistype an operator?
4383 =item Overloaded dereference did not return a reference
4385 (F) An object with an overloaded dereference operator was dereferenced,
4386 but the overloaded operation did not return a reference. See
4389 =item Overloaded qr did not return a REGEXP
4391 (F) An object with a C<qr> overload was used as part of a match, but the
4392 overloaded operation didn't return a compiled regexp. See L<overload>.
4394 =item %s package attribute may clash with future reserved word: %s
4396 (W reserved) A lowercase attribute name was used that had a
4397 package-specific handler. That name might have a meaning to Perl itself
4398 some day, even though it doesn't yet. Perhaps you should use a
4399 mixed-case attribute name, instead. See L<attributes>.
4401 =item pack/unpack repeat count overflow
4403 (F) You can't specify a repeat count so large that it overflows your
4404 signed integers. See L<perlfunc/pack>.
4408 (W io) A single call to write() produced more lines than can fit on a
4409 page. See L<perlform>.
4413 (P) An internal error.
4415 =item panic: attempt to call %s in %s
4417 (P) One of the file test operators entered a code branch that calls
4418 an ACL related-function, but that function is not available on this
4419 platform. Earlier checks mean that it should not be possible to
4420 enter this branch on this platform.
4422 =item panic: child pseudo-process was never scheduled
4424 (P) A child pseudo-process in the ithreads implementation on Windows
4425 was not scheduled within the time period allowed and therefore was not
4426 able to initialize properly.
4428 =item panic: ck_grep, type=%u
4430 (P) Failed an internal consistency check trying to compile a grep.
4432 =item panic: ck_split, type=%u
4434 (P) Failed an internal consistency check trying to compile a split.
4436 =item panic: corrupt saved stack index %ld
4438 (P) The savestack was requested to restore more localized values than
4439 there are in the savestack.
4441 =item panic: del_backref
4443 (P) Failed an internal consistency check while trying to reset a weak
4446 =item panic: do_subst
4448 (P) The internal pp_subst() routine was called with invalid operational
4451 =item panic: do_trans_%s
4453 (P) The internal do_trans routines were called with invalid operational
4456 =item panic: fold_constants JMPENV_PUSH returned %d
4458 (P) While attempting folding constants an exception other than an C<eval>
4461 =item panic: frexp: %f
4463 (P) The library function frexp() failed, making printf("%f") impossible.
4465 =item panic: goto, type=%u, ix=%ld
4467 (P) We popped the context stack to a context with the specified label,
4468 and then discovered it wasn't a context we know how to do a goto in.
4470 =item panic: gp_free failed to free glob pointer
4472 (P) The internal routine used to clear a typeglob's entries tried
4473 repeatedly, but each time something re-created entries in the glob.
4474 Most likely the glob contains an object with a reference back to
4475 the glob and a destructor that adds a new object to the glob.
4477 =item panic: INTERPCASEMOD, %s
4479 (P) The lexer got into a bad state at a case modifier.
4481 =item panic: INTERPCONCAT, %s
4483 (P) The lexer got into a bad state parsing a string with brackets.
4485 =item panic: kid popen errno read
4487 (F) A forked child returned an incomprehensible message about its errno.
4489 =item panic: last, type=%u
4491 (P) We popped the context stack to a block context, and then discovered
4492 it wasn't a block context.
4494 =item panic: leave_scope clearsv
4496 (P) A writable lexical variable became read-only somehow within the
4499 =item panic: leave_scope inconsistency %u
4501 (P) The savestack probably got out of sync. At least, there was an
4502 invalid enum on the top of it.
4504 =item panic: magic_killbackrefs
4506 (P) Failed an internal consistency check while trying to reset all weak
4507 references to an object.
4509 =item panic: malloc, %s
4511 (P) Something requested a negative number of bytes of malloc.
4513 =item panic: memory wrap
4515 (P) Something tried to allocate either more memory than possible or a
4518 =item panic: pad_alloc, %p!=%p
4520 (P) The compiler got confused about which scratch pad it was allocating
4521 and freeing temporaries and lexicals from.
4523 =item panic: pad_free curpad, %p!=%p
4525 (P) The compiler got confused about which scratch pad it was allocating
4526 and freeing temporaries and lexicals from.
4528 =item panic: pad_free po
4530 (P) A zero scratch pad offset was detected internally. An attempt was
4531 made to free a target that had not been allocated to begin with.
4533 =item panic: pad_reset curpad, %p!=%p
4535 (P) The compiler got confused about which scratch pad it was allocating
4536 and freeing temporaries and lexicals from.
4538 =item panic: pad_sv po
4540 (P) A zero scratch pad offset was detected internally. Most likely
4541 an operator needed a target but that target had not been allocated
4542 for whatever reason.
4544 =item panic: pad_swipe curpad, %p!=%p
4546 (P) The compiler got confused about which scratch pad it was allocating
4547 and freeing temporaries and lexicals from.
4549 =item panic: pad_swipe po
4551 (P) An invalid scratch pad offset was detected internally.
4553 =item panic: pp_iter, type=%u
4555 (P) The foreach iterator got called in a non-loop context frame.
4557 =item panic: pp_match%s
4559 (P) The internal pp_match() routine was called with invalid operational
4562 =item panic: pp_split, pm=%p, s=%p
4564 (P) Something terrible went wrong in setting up for the split.
4566 =item panic: realloc, %s
4568 (P) Something requested a negative number of bytes of realloc.
4570 =item panic: reference miscount on nsv in sv_replace() (%d != 1)
4572 (P) The internal sv_replace() function was handed a new SV with a
4573 reference count other than 1.
4575 =item panic: restartop in %s
4577 (P) Some internal routine requested a goto (or something like it), and
4578 didn't supply the destination.
4580 =item panic: return, type=%u
4582 (P) We popped the context stack to a subroutine or eval context, and
4583 then discovered it wasn't a subroutine or eval context.
4585 =item panic: scan_num, %s
4587 (P) scan_num() got called on something that wasn't a number.
4589 =item panic: Sequence (?{...}): no code block found in regex m/%s/
4591 (P) While compiling a pattern that has embedded (?{}) or (??{}) code
4592 blocks, perl couldn't locate the code block that should have already been
4593 seen and compiled by perl before control passed to the regex compiler.
4595 =item panic: strxfrm() gets absurd - a => %u, ab => %u
4597 (P) The interpreter's sanity check of the C function strxfrm() failed.
4598 In your current locale the returned transformation of the string "ab"
4599 is shorter than that of the string "a", which makes no sense.
4601 =item panic: sv_chop %s
4603 (P) The sv_chop() routine was passed a position that is not within the
4604 scalar's string buffer.
4606 =item panic: sv_insert, midend=%p, bigend=%p
4608 (P) The sv_insert() routine was told to remove more string than there
4611 =item panic: top_env
4613 (P) The compiler attempted to do a goto, or something weird like that.
4615 =item panic: unimplemented op %s (#%d) called
4617 (P) The compiler is screwed up and attempted to use an op that isn't
4618 permitted at run time.
4620 =item panic: unknown OA_*: %x
4622 (P) The internal routine that handles arguments to C<&CORE::foo()>
4623 subroutine calls was unable to determine what type of arguments
4626 =item panic: utf16_to_utf8: odd bytelen
4628 (P) Something tried to call utf16_to_utf8 with an odd (as opposed
4629 to even) byte length.
4631 =item panic: utf16_to_utf8_reversed: odd bytelen
4633 (P) Something tried to call utf16_to_utf8_reversed with an odd (as opposed
4634 to even) byte length.
4636 =item panic: yylex, %s
4638 (P) The lexer got into a bad state while processing a case modifier.
4640 =item Parentheses missing around "%s" list
4642 (W parenthesis) You said something like
4648 my ($foo, $bar) = @_;
4650 Remember that "my", "our", "local" and "state" bind tighter than comma.
4652 =item Parsing code internal error (%s)
4654 (F) Parsing code supplied by an extension violated the parser's API in
4657 =item Passing malformed UTF-8 to "%s" is deprecated
4659 (D deprecated, utf8) This message indicates a bug either in the Perl
4660 core or in XS code. Such code was trying to find out if a character,
4661 allegedly stored internally encoded as UTF-8, was of a given type, such
4662 as being punctuation or a digit. But the character was not encoded in
4663 legal UTF-8. The C<%s> is replaced by a string that can be used by
4664 knowledgeable people to determine what the type being checked against
4665 was. If C<utf8> warnings are enabled, a further message is raised,
4666 giving details of the malformation.
4668 =item Pattern subroutine nesting without pos change exceeded limit in regex
4670 (F) You used a pattern that uses too many nested subpattern calls without
4671 consuming any text. Restructure the pattern so text is consumed before
4672 the nesting limit is exceeded.
4674 =item C<-p> destination: %s
4676 (F) An error occurred during the implicit output invoked by the C<-p>
4677 command-line switch. (This output goes to STDOUT unless you've
4678 redirected it with select().)
4680 =item Perl API version %s of %s does not match %s
4682 (F) The XS module in question was compiled against a different incompatible
4683 version of Perl than the one that has loaded the XS module.
4685 =item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
4686 utility to report; in regex; marked by S<<-- HERE> in m/%s/
4688 (S regexp) You used a regular expression with case-insensitive matching,
4689 and there is a bug in Perl in which the built-in regular expression
4690 folding rules are not accurate. This may lead to incorrect results.
4691 Please report this as a bug using the L<perlbug> utility.
4693 =item PerlIO layer ':win32' is experimental
4695 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
4696 experimental. If you want to take the risk of using this layer,
4697 simply disable this warning:
4699 no warnings "experimental::win32_perlio";
4701 =item Perl_my_%s() not available
4703 (F) Your platform has very uncommon byte-order and integer size,
4704 so it was not possible to set up some or all fixed-width byte-order
4705 conversion functions. This is only a problem when you're using the
4706 '<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
4708 =item Perl %s required (did you mean %s?)--this is only %s, stopped
4710 (F) The code you are trying to run has asked for a newer version of
4711 Perl than you are running. Perhaps C<use 5.10> was written instead
4712 of C<use 5.010> or C<use v5.10>. Without the leading C<v>, the number is
4713 interpreted as a decimal, with every three digits after the
4714 decimal point representing a part of the version number. So 5.10
4715 is equivalent to v5.100.
4717 =item Perl %s required--this is only %s, stopped
4719 (F) The module in question uses features of a version of Perl more
4720 recent than the currently running version. How long has it been since
4721 you upgraded, anyway? See L<perlfunc/require>.
4723 =item PERL_SH_DIR too long
4725 (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
4726 C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
4728 =item PERL_SIGNALS illegal: "%s"
4730 (X) See L<perlrun/PERL_SIGNALS> for legal values.
4732 =item Perls since %s too modern--this is %s, stopped
4734 (F) The code you are trying to run claims it will not run
4735 on the version of Perl you are using because it is too new.
4736 Maybe the code needs to be updated, or maybe it is simply
4737 wrong and the version check should just be removed.
4739 =item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only partially set
4741 (S) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
4742 contained a non hex character. This could mean you are not using the
4743 hash seed you think you are.
4745 =item perl: warning: Setting locale failed.
4747 (S) The whole warning message will look something like:
4749 perl: warning: Setting locale failed.
4750 perl: warning: Please check that your locale settings:
4753 are supported and installed on your system.
4754 perl: warning: Falling back to the standard locale ("C").
4756 Exactly what were the failed locale settings varies. In the above the
4757 settings were that the LC_ALL was "En_US" and the LANG had no value.
4758 This error means that Perl detected that you and/or your operating
4759 system supplier and/or system administrator have set up the so-called
4760 locale system but Perl could not use those settings. This was not
4761 dead serious, fortunately: there is a "default locale" called "C" that
4762 Perl can and will use, and the script will be run. Before you really
4763 fix the problem, however, you will get the same error message each
4764 time you run Perl. How to really fix the problem can be found in
4765 L<perllocale> section B<LOCALE PROBLEMS>.
4767 =item perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
4769 (S) Perl was run with the environment variable PERL_PERTURB_KEYS defined
4770 but containing an unexpected value. The legal values of this setting
4773 Numeric | String | Result
4774 --------+---------------+-----------------------------------------
4775 0 | NO | Disables key traversal randomization
4776 1 | RANDOM | Enables full key traversal randomization
4777 2 | DETERMINISTIC | Enables repeatable key traversal
4780 Both numeric and string values are accepted, but note that string values are
4781 case sensitive. The default for this setting is "RANDOM" or 1.
4783 =item pid %x not a child
4785 (W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
4786 process which isn't a subprocess of the current process. While this is
4787 fine from VMS' perspective, it's probably not what you intended.
4789 =item 'P' must have an explicit size in unpack
4791 (F) The unpack format P must have an explicit size, not "*".
4793 =item POSIX class [:%s:] unknown in regex; marked by S<<-- HERE> in m/%s/
4795 (F) The class in the character class [: :] syntax is unknown. The S<<-- HERE>
4796 shows whereabouts in the regular expression the problem was discovered.
4797 Note that the POSIX character classes do B<not> have the C<is> prefix
4798 the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
4799 not C<isprint>. See L<perlre>.
4801 =item POSIX getpgrp can't take an argument
4803 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
4804 the BSD version, which takes a pid.
4806 =item POSIX syntax [%c %c] belongs inside character classes%s in regex; marked by
4807 S<<-- HERE> in m/%s/
4809 (W regexp) Perl thinks that you intended to write a POSIX character
4810 class, but didn't use enough brackets. These POSIX class constructs [:
4811 :], [= =], and [. .] go I<inside> character classes, the [] are part of
4812 the construct, for example: C<qr/[012[:alpha:]345]/>. What the regular
4813 expression pattern compiled to is probably not what you were intending.
4814 For example, C<qr/[:alpha:]/> compiles to a regular bracketed character
4815 class consisting of the four characters C<":">, C<"a">, C<"l">,
4816 C<"h">, and C<"p">. To specify the POSIX class, it should have been
4817 written C<qr/[[:alpha:]]/>.
4819 Note that [= =] and [. .] are not currently
4820 implemented; they are simply placeholders for future extensions and
4821 will cause fatal errors. The S<<-- HERE> shows whereabouts in the regular
4822 expression the problem was discovered. See L<perlre>.
4824 If the specification of the class was not completely valid, the message
4827 =item POSIX syntax [. .] is reserved for future extensions in regex; marked by
4828 S<<-- HERE> in m/%s/
4830 (F) Within regular expression character classes ([]) the syntax beginning
4831 with "[." and ending with ".]" is reserved for future extensions. If you
4832 need to represent those character sequences inside a regular expression
4833 character class, just quote the square brackets with the backslash: "\[."
4834 and ".\]". The S<<-- HERE> shows whereabouts in the regular expression the
4835 problem was discovered. See L<perlre>.
4837 =item POSIX syntax [= =] is reserved for future extensions in regex; marked by
4838 S<<-- HERE> in m/%s/
4840 (F) Within regular expression character classes ([]) the syntax beginning
4841 with "[=" and ending with "=]" is reserved for future extensions. If you
4842 need to represent those character sequences inside a regular expression
4843 character class, just quote the square brackets with the backslash: "\[="
4844 and "=\]". The S<<-- HERE> shows whereabouts in the regular expression the
4845 problem was discovered. See L<perlre>.
4847 =item Possible attempt to put comments in qw() list
4849 (W qw) qw() lists contain items separated by whitespace; as with literal
4850 strings, comment characters are not ignored, but are instead treated as
4851 literal data. (You may have used different delimiters than the
4852 parentheses shown here; braces are also frequently used.)
4854 You probably wrote something like this:
4861 when you should have written this:
4868 If you really want comments, build your list the
4869 old-fashioned way, with quotes and commas:
4873 'b', # another comment
4876 =item Possible attempt to separate words with commas
4878 (W qw) qw() lists contain items separated by whitespace; therefore
4879 commas aren't needed to separate the items. (You may have used
4880 different delimiters than the parentheses shown here; braces are also
4883 You probably wrote something like this:
4887 which puts literal commas into some of the list items. Write it without
4888 commas if you don't want them to appear in your data:
4892 =item Possible memory corruption: %s overflowed 3rd argument
4894 (F) An ioctl() or fcntl() returned more than Perl was bargaining for.
4895 Perl guesses a reasonable buffer size, but puts a sentinel byte at the
4896 end of the buffer just in case. This sentinel byte got clobbered, and
4897 Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
4899 =item Possible precedence issue with control flow operator
4901 (W syntax) There is a possible problem with the mixing of a control
4902 flow operator (e.g. C<return>) and a low-precedence operator like
4905 sub { return $a or $b; }
4909 sub { (return $a) or $b; }
4911 Which is effectively just:
4915 Either use parentheses or the high-precedence variant of the operator.
4917 Note this may be also triggered for constructs like:
4921 =item Possible precedence problem on bitwise %s operator
4923 (W precedence) Your program uses a bitwise logical operator in conjunction
4924 with a numeric comparison operator, like this :
4926 if ($x & $y == 0) { ... }
4928 This expression is actually equivalent to C<$x & ($y == 0)>, due to the
4929 higher precedence of C<==>. This is probably not what you want. (If you
4930 really meant to write this, disable the warning, or, better, put the
4931 parentheses explicitly and write C<$x & ($y == 0)>).
4933 =item Possible unintended interpolation of $\ in regex
4935 (W ambiguous) You said something like C<m/$\/> in a regex.
4936 The regex C<m/foo$\s+bar/m> translates to: match the word 'foo', the output
4937 record separator (see L<perlvar/$\>) and the letter 's' (one time or more)
4938 followed by the word 'bar'.
4940 If this is what you intended then you can silence the warning by using
4941 C<m/${\}/> (for example: C<m/foo${\}s+bar/>).
4943 If instead you intended to match the word 'foo' at the end of the line
4944 followed by whitespace and the word 'bar' on the next line then you can use
4945 C<m/$(?)\/> (for example: C<m/foo$(?)\s+bar/>).
4947 =item Possible unintended interpolation of %s in string
4949 (W ambiguous) You said something like '@foo' in a double-quoted string
4950 but there was no array C<@foo> in scope at the time. If you wanted a
4951 literal @foo, then write it as \@foo; otherwise find out what happened
4952 to the array you apparently lost track of.
4954 =item Precedence problem: open %s should be open(%s)
4956 (S precedence) The old irregular construct
4960 is now misinterpreted as
4964 because of the strict regularization of Perl 5's grammar into unary and
4965 list operators. (The old open was a little of both.) You must put
4966 parentheses around the filehandle, or use the new "or" operator instead
4969 =item Premature end of script headers
4973 =item printf() on closed filehandle %s
4975 (W closed) The filehandle you're writing to got itself closed sometime
4976 before now. Check your control flow.
4978 =item print() on closed filehandle %s
4980 (W closed) The filehandle you're printing on got itself closed sometime
4981 before now. Check your control flow.
4983 =item Process terminated by SIG%s
4985 (W) This is a standard message issued by OS/2 applications, while *nix
4986 applications die in silence. It is considered a feature of the OS/2
4987 port. One can easily disable this by appropriate sighandlers, see
4988 L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
4991 =item Prototype after '%c' for %s : %s
4993 (W illegalproto) A character follows % or @ in a prototype. This is
4994 useless, since % and @ gobble the rest of the subroutine arguments.
4996 =item Prototype mismatch: %s vs %s
4998 (S prototype) The subroutine being declared or defined had previously been
4999 declared or defined with a different function prototype.
5001 =item Prototype not terminated
5003 (F) You've omitted the closing parenthesis in a function prototype
5006 =item Prototype '%s' overridden by attribute 'prototype(%s)' in %s
5008 (W prototype) A prototype was declared in both the parentheses after
5009 the sub name and via the prototype attribute. The prototype in
5010 parentheses is useless, since it will be replaced by the prototype
5011 from the attribute before it's ever used.
5013 =item Quantifier follows nothing in regex; marked by S<<-- HERE> in m/%s/
5015 (F) You started a regular expression with a quantifier. Backslash it if
5016 you meant it literally. The S<<-- HERE> shows whereabouts in the regular
5017 expression the problem was discovered. See L<perlre>.
5019 =item Quantifier in {,} bigger than %d in regex; marked by S<<-- HERE> in m/%s/
5021 (F) There is currently a limit to the size of the min and max values of
5022 the {min,max} construct. The S<<-- HERE> shows whereabouts in the regular
5023 expression the problem was discovered. See L<perlre>.
5025 =item Quantifier {n,m} with n > m can't match in regex
5027 =item Quantifier {n,m} with n > m can't match in regex; marked by
5028 S<<-- HERE> in m/%s/
5030 (W regexp) Minima should be less than or equal to maxima. If you really
5031 want your regexp to match something 0 times, just put {0}.
5033 =item Quantifier unexpected on zero-length expression in regex m/%s/
5035 (W regexp) You applied a regular expression quantifier in a place where
5036 it makes no sense, such as on a zero-width assertion. Try putting the
5037 quantifier inside the assertion instead. For example, the way to match
5038 "abc" provided that it is followed by three repetitions of "xyz" is
5039 C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
5041 =item Range iterator outside integer range
5043 (F) One (or both) of the numeric arguments to the range operator ".."
5044 are outside the range which can be represented by integers internally.
5045 One possible workaround is to force Perl to use magical string increment
5046 by prepending "0" to your numbers.
5048 =item Ranges of ASCII printables should be some subset of "0-9", "A-Z", or
5049 "a-z" in regex; marked by S<<-- HERE> in m/%s/
5051 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
5053 Stricter rules help to find typos and other errors. Perhaps you didn't
5054 even intend a range here, if the C<"-"> was meant to be some other
5055 character, or should have been escaped (like C<"\-">). If you did
5056 intend a range, the one that was used is not portable between ASCII and
5057 EBCDIC platforms, and doesn't have an obvious meaning to a casual
5060 [3-7] # OK; Obvious and portable
5061 [d-g] # OK; Obvious and portable
5062 [A-Y] # OK; Obvious and portable
5063 [A-z] # WRONG; Not portable; not clear what is meant
5064 [a-Z] # WRONG; Not portable; not clear what is meant
5065 [%-.] # WRONG; Not portable; not clear what is meant
5066 [\x41-Z] # WRONG; Not portable; not obvious to non-geek
5068 (You can force portability by specifying a Unicode range, which means that
5069 the endpoints are specified by
5070 L<C<\N{...}>|perlrecharclass/Character Ranges>, but the meaning may
5071 still not be obvious.)
5072 The stricter rules require that ranges that start or stop with an ASCII
5073 character that is not a control have all their endpoints be the literal
5074 character, and not some escape sequence (like C<"\x41">), and the ranges
5075 must be all digits, or all uppercase letters, or all lowercase letters.
5077 =item Ranges of digits should be from the same group in regex; marked by
5078 S<<-- HERE> in m/%s/
5080 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
5082 Stricter rules help to find typos and other errors. You included a
5083 range, and at least one of the end points is a decimal digit. Under the
5084 stricter rules, when this happens, both end points should be digits in
5085 the same group of 10 consecutive digits.
5087 =item readdir() attempted on invalid dirhandle %s
5089 (W io) The dirhandle you're reading from is either closed or not really
5090 a dirhandle. Check your control flow.
5092 =item readline() on closed filehandle %s
5094 (W closed) The filehandle you're reading from got itself closed sometime
5095 before now. Check your control flow.
5097 =item read() on closed filehandle %s
5099 (W closed) You tried to read from a closed filehandle.
5101 =item read() on unopened filehandle %s
5103 (W unopened) You tried to read from a filehandle that was never opened.
5105 =item Reallocation too large: %x
5107 (F) You can't allocate more than 64K on an MS-DOS machine.
5109 =item realloc() of freed memory ignored
5111 (S malloc) An internal routine called realloc() on something that had
5114 =item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
5116 (S debugging) You can't use the B<-D> option unless the code to produce
5117 the desired output is compiled into Perl, which entails some overhead,
5118 which is why it's currently left out of your copy.
5120 =item Recursive call to Perl_load_module in PerlIO_find_layer
5122 (P) It is currently not permitted to load modules when creating
5123 a filehandle inside an %INC hook. This can happen with C<open my
5124 $fh, '<', \$scalar>, which implicitly loads PerlIO::scalar. Try
5125 loading PerlIO::scalar explicitly first.
5127 =item Recursive inheritance detected in package '%s'
5129 (F) While calculating the method resolution order (MRO) of a package, Perl
5130 believes it found an infinite loop in the C<@ISA> hierarchy. This is a
5131 crude check that bails out after 100 levels of C<@ISA> depth.
5133 =item Redundant argument in %s
5135 (W redundant) You called a function with more arguments than other
5136 arguments you supplied indicated would be needed. Currently only
5137 emitted when a printf-type format required fewer arguments than were
5138 supplied, but might be used in the future for e.g. L<perlfunc/pack>.
5140 =item refcnt_dec: fd %d%s
5142 =item refcnt: fd %d%s
5144 =item refcnt_inc: fd %d%s
5146 (P) Perl's I/O implementation failed an internal consistency check. If
5147 you see this message, something is very wrong.
5149 =item Reference found where even-sized list expected
5151 (W misc) You gave a single reference where Perl was expecting a list
5152 with an even number of elements (for assignment to a hash). This
5153 usually means that you used the anon hash constructor when you meant
5154 to use parens. In any case, a hash requires key/value B<pairs>.
5156 %hash = { one => 1, two => 2, }; # WRONG
5157 %hash = [ qw/ an anon array / ]; # WRONG
5158 %hash = ( one => 1, two => 2, ); # right
5159 %hash = qw( one 1 two 2 ); # also fine
5161 =item Reference is already weak
5163 (W misc) You have attempted to weaken a reference that is already weak.
5164 Doing so has no effect.
5166 =item Reference to invalid group 0 in regex; marked by S<<-- HERE> in m/%s/
5168 (F) You used C<\g0> or similar in a regular expression. You may refer
5169 to capturing parentheses only with strictly positive integers
5170 (normal backreferences) or with strictly negative integers (relative
5171 backreferences). Using 0 does not make sense.
5173 =item Reference to nonexistent group in regex; marked by S<<-- HERE> in
5176 (F) You used something like C<\7> in your regular expression, but there are
5177 not at least seven sets of capturing parentheses in the expression. If
5178 you wanted to have the character with ordinal 7 inserted into the regular
5179 expression, prepend zeroes to make it three digits long: C<\007>
5181 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5184 =item Reference to nonexistent named group in regex; marked by S<<-- HERE>
5187 (F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
5188 expression, but there is no corresponding named capturing parentheses
5189 such as C<(?'NAME'...)> or C<< (?<NAME>...) >>. Check if the name has been
5190 spelled correctly both in the backreference and the declaration.
5192 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5195 =item Reference to nonexistent or unclosed group in regex; marked by
5196 S<<-- HERE> in m/%s/
5198 (F) You used something like C<\g{-7}> in your regular expression, but there
5199 are not at least seven sets of closed capturing parentheses in the
5200 expression before where the C<\g{-7}> was located.
5202 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5205 =item regexp memory corruption
5207 (P) The regular expression engine got confused by what the regular
5208 expression compiler gave it.
5210 =item Regexp modifier "/%c" may appear a maximum of twice
5212 =item Regexp modifier "%c" may appear a maximum of twice in regex; marked
5213 by S<<-- HERE> in m/%s/
5215 (F) The regular expression pattern had too many occurrences
5216 of the specified modifier. Remove the extraneous ones.
5218 =item Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
5221 (F) Turning off the given modifier has the side effect of turning on
5222 another one. Perl currently doesn't allow this. Reword the regular
5223 expression to use the modifier you want to turn on (and place it before
5224 the minus), instead of the one you want to turn off.
5226 =item Regexp modifier "/%c" may not appear twice
5228 =item Regexp modifier "%c" may not appear twice in regex; marked by <--
5231 (F) The regular expression pattern had too many occurrences
5232 of the specified modifier. Remove the extraneous ones.
5234 =item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5236 =item Regexp modifiers "%c" and "%c" are mutually exclusive in regex;
5237 marked by S<<-- HERE> in m/%s/
5239 (F) The regular expression pattern had more than one of these
5240 mutually exclusive modifiers. Retain only the modifier that is
5241 supposed to be there.
5243 =item Regexp out of space in regex m/%s/
5245 (P) A "can't happen" error, because safemalloc() should have caught it
5248 =item Repeated format line will never terminate (~~ and @#)
5250 (F) Your format contains the ~~ repeat-until-blank sequence and a
5251 numeric field that will never go blank so that the repetition never
5252 terminates. You might use ^# instead. See L<perlform>.
5254 =item Replacement list is longer than search list
5256 (W misc) You have used a replacement list that is longer than the
5257 search list. So the additional elements in the replacement list
5260 =item '%s' resolved to '\o{%s}%d'
5262 (W misc, regexp) You wrote something like C<\08>, or C<\179> in a
5263 double-quotish string. All but the last digit is treated as a single
5264 character, specified in octal. The last digit is the next character in
5265 the string. To tell Perl that this is indeed what you want, you can use
5266 the C<\o{ }> syntax, or use exactly three digits to specify the octal
5269 =item Reversed %s= operator
5271 (W syntax) You wrote your assignment operator backwards. The = must
5272 always come last, to avoid ambiguity with subsequent unary operators.
5274 =item rewinddir() attempted on invalid dirhandle %s
5276 (W io) The dirhandle you tried to do a rewinddir() on is either closed
5277 or not really a dirhandle. Check your control flow.
5279 =item Scalars leaked: %d
5281 (S internal) Something went wrong in Perl's internal bookkeeping
5282 of scalars: not all scalar variables were deallocated by the time
5283 Perl exited. What this usually indicates is a memory leak, which
5284 is of course bad, especially if the Perl program is intended to be
5287 =item Scalar value @%s[%s] better written as $%s[%s]
5289 (W syntax) You've used an array slice (indicated by @) to select a
5290 single element of an array. Generally it's better to ask for a scalar
5291 value (indicated by $). The difference is that C<$foo[&bar]> always
5292 behaves like a scalar, both when assigning to it and when evaluating its
5293 argument, while C<@foo[&bar]> behaves like a list when you assign to it,
5294 and provides a list context to its subscript, which can do weird things
5295 if you're expecting only one subscript.
5297 On the other hand, if you were actually hoping to treat the array
5298 element as a list, you need to look into how references work, because
5299 Perl will not magically convert between scalars and lists for you. See
5302 =item Scalar value @%s{%s} better written as $%s{%s}
5304 (W syntax) You've used a hash slice (indicated by @) to select a single
5305 element of a hash. Generally it's better to ask for a scalar value
5306 (indicated by $). The difference is that C<$foo{&bar}> always behaves
5307 like a scalar, both when assigning to it and when evaluating its
5308 argument, while C<@foo{&bar}> behaves like a list when you assign to it,
5309 and provides a list context to its subscript, which can do weird things
5310 if you're expecting only one subscript.
5312 On the other hand, if you were actually hoping to treat the hash element
5313 as a list, you need to look into how references work, because Perl will
5314 not magically convert between scalars and lists for you. See
5317 =item Search pattern not terminated
5319 (F) The lexer couldn't find the final delimiter of a // or m{}
5320 construct. Remember that bracketing delimiters count nesting level.
5321 Missing the leading C<$> from a variable C<$m> may cause this error.
5323 Note that since Perl 5.10.0 a // can also be the I<defined-or>
5324 construct, not just the empty search pattern. Therefore code written
5325 in Perl 5.10.0 or later that uses the // as the I<defined-or> can be
5326 misparsed by pre-5.10.0 Perls as a non-terminated search pattern.
5328 =item seekdir() attempted on invalid dirhandle %s
5330 (W io) The dirhandle you are doing a seekdir() on is either closed or not
5331 really a dirhandle. Check your control flow.
5333 =item %sseek() on unopened filehandle
5335 (W unopened) You tried to use the seek() or sysseek() function on a
5336 filehandle that was either never opened or has since been closed.
5338 =item select not implemented
5340 (F) This machine doesn't implement the select() system call.
5342 =item Self-ties of arrays and hashes are not supported
5344 (F) Self-ties are of arrays and hashes are not supported in
5345 the current implementation.
5347 =item Semicolon seems to be missing
5349 (W semicolon) A nearby syntax error was probably caused by a missing
5350 semicolon, or possibly some other missing operator, such as a comma.
5352 =item semi-panic: attempt to dup freed string
5354 (S internal) The internal newSVsv() routine was called to duplicate a
5355 scalar that had previously been marked as free.
5357 =item sem%s not implemented
5359 (F) You don't have System V semaphore IPC on your system.
5361 =item send() on closed socket %s
5363 (W closed) The socket you're sending to got itself closed sometime
5364 before now. Check your control flow.
5366 =item Sequence "\c{" invalid
5368 (F) These three characters may not appear in sequence in a
5369 double-quotish context. This message is raised only on non-ASCII
5370 platforms (a different error message is output on ASCII ones). If you
5371 were intending to specify a control character with this sequence, you'll
5372 have to use a different way to specify it.
5374 =item Sequence (? incomplete in regex; marked by S<<-- HERE> in m/%s/
5376 (F) A regular expression ended with an incomplete extension (?. The
5377 S<<-- HERE> shows whereabouts in the regular expression the problem was
5378 discovered. See L<perlre>.
5380 =item Sequence (?%c...) not implemented in regex; marked by S<<-- HERE> in
5383 (F) A proposed regular expression extension has the character reserved
5384 but has not yet been written. The S<<-- HERE> shows whereabouts in the
5385 regular expression the problem was discovered. See L<perlre>.
5387 =item Sequence (?%s...) not recognized in regex; marked by S<<-- HERE> in
5390 (F) You used a regular expression extension that doesn't make sense.
5391 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5392 discovered. This may happen when using the C<(?^...)> construct to tell
5393 Perl to use the default regular expression modifiers, and you
5394 redundantly specify a default modifier. For other
5395 causes, see L<perlre>.
5397 =item Sequence (?#... not terminated in regex m/%s/
5399 (F) A regular expression comment must be terminated by a closing
5400 parenthesis. Embedded parentheses aren't allowed. See
5403 =item Sequence (?&... not terminated in regex; marked by S<<-- HERE> in
5406 (F) A named reference of the form C<(?&...)> was missing the final
5407 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5408 in the regular expression the problem was discovered.
5410 =item Sequence (?%c... not terminated in regex; marked by S<<-- HERE>
5413 (F) A named group of the form C<(?'...')> or C<< (?<...>) >> was missing the final
5414 closing quote or angle bracket. The S<<-- HERE> shows whereabouts in the
5415 regular expression the problem was discovered.
5417 =item Sequence (?(%c... not terminated in regex; marked by S<<-- HERE>
5420 (F) A named reference of the form C<(?('...')...)> or C<< (?(<...>)...) >> was
5421 missing the final closing quote or angle bracket after the name. The
5422 S<<-- HERE> shows whereabouts in the regular expression the problem was
5425 =item Sequence (?... not terminated in regex; marked by S<<-- HERE> in
5428 (F) There was no matching closing parenthesis for the '('. The
5429 S<<-- HERE> shows whereabouts in the regular expression the problem was
5432 =item Sequence \%s... not terminated in regex; marked by S<<-- HERE> in
5435 (F) The regular expression expects a mandatory argument following the escape
5436 sequence and this has been omitted or incorrectly written.
5438 =item Sequence (?{...}) not terminated with ')'
5440 (F) The end of the perl code contained within the {...} must be
5441 followed immediately by a ')'.
5443 =item Sequence (?PE<gt>... not terminated in regex; marked by S<<-- HERE> in m/%s/
5445 (F) A named reference of the form C<(?PE<gt>...)> was missing the final
5446 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5447 in the regular expression the problem was discovered.
5449 =item Sequence (?PE<lt>... not terminated in regex; marked by S<<-- HERE> in m/%s/
5451 (F) A named group of the form C<(?PE<lt>...E<gt>')> was missing the final
5452 closing angle bracket. The S<<-- HERE> shows whereabouts in the
5453 regular expression the problem was discovered.
5455 =item Sequence ?P=... not terminated in regex; marked by S<<-- HERE> in
5458 (F) A named reference of the form C<(?P=...)> was missing the final
5459 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5460 in the regular expression the problem was discovered.
5462 =item Sequence (?R) not terminated in regex m/%s/
5464 (F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
5467 =item Server error (a.k.a. "500 Server error")
5469 (A) This is the error message generally seen in a browser window
5470 when trying to run a CGI program (including SSI) over the web. The
5471 actual error text varies widely from server to server. The most
5472 frequently-seen variants are "500 Server error", "Method (something)
5473 not permitted", "Document contains no data", "Premature end of script
5474 headers", and "Did not produce a valid header".
5476 B<This is a CGI error, not a Perl error>.
5478 You need to make sure your script is executable, is accessible by
5479 the user CGI is running the script under (which is probably not the
5480 user account you tested it under), does not rely on any environment
5481 variables (like PATH) from the user it isn't running under, and isn't
5482 in a location where the CGI server can't find it, basically, more or
5483 less. Please see the following for more information:
5485 http://www.perl.org/CGI_MetaFAQ.html
5486 http://www.htmlhelp.org/faq/cgifaq.html
5487 http://www.w3.org/Security/Faq/
5489 You should also look at L<perlfaq9>.
5491 =item setegid() not implemented
5493 (F) You tried to assign to C<$)>, and your operating system doesn't
5494 support the setegid() system call (or equivalent), or at least Configure
5497 =item seteuid() not implemented
5499 (F) You tried to assign to C<< $> >>, and your operating system doesn't
5500 support the seteuid() system call (or equivalent), or at least Configure
5503 =item setpgrp can't take arguments
5505 (F) Your system has the setpgrp() from BSD 4.2, which takes no
5506 arguments, unlike POSIX setpgid(), which takes a process ID and process
5509 =item setrgid() not implemented
5511 (F) You tried to assign to C<$(>, and your operating system doesn't
5512 support the setrgid() system call (or equivalent), or at least Configure
5515 =item setruid() not implemented
5517 (F) You tried to assign to C<$<>, and your operating system doesn't
5518 support the setruid() system call (or equivalent), or at least Configure
5521 =item setsockopt() on closed socket %s
5523 (W closed) You tried to set a socket option on a closed socket. Did you
5524 forget to check the return value of your socket() call? See
5525 L<perlfunc/setsockopt>.
5527 =item Setting ${^ENCODING} is deprecated
5529 (D deprecated) You assigned a non-C<undef> value to C<${^ENCODING}>.
5530 This is deprecated; see C<L<perlvar/${^ENCODING}>> for details.
5532 =item Setting $/ to a reference to %s as a form of slurp is deprecated, treating as undef
5534 (D deprecated) You assigned a reference to a scalar to C<$/> where the
5535 referenced item is not a positive integer. In older perls this B<appeared>
5536 to work the same as setting it to C<undef> but was in fact internally
5537 different, less efficient and with very bad luck could have resulted in
5538 your file being split by a stringified form of the reference.
5540 In Perl 5.20.0 this was changed so that it would be B<exactly> the same as
5541 setting C<$/> to undef, with the exception that this warning would be
5544 You are recommended to change your code to set C<$/> to C<undef> explicitly
5545 if you wish to slurp the file. In future versions of Perl assigning
5546 a reference to will throw a fatal error.
5548 =item Setting $/ to %s reference is forbidden
5550 (F) You tried to assign a reference to a non integer to C<$/>. In older
5551 Perls this would have behaved similarly to setting it to a reference to
5552 a positive integer, where the integer was the address of the reference.
5553 As of Perl 5.20.0 this is a fatal error, to allow future versions of Perl
5554 to use non-integer refs for more interesting purposes.
5556 =item shm%s not implemented
5558 (F) You don't have System V shared memory IPC on your system.
5560 =item !=~ should be !~
5562 (W syntax) The non-matching operator is !~, not !=~. !=~ will be
5563 interpreted as the != (numeric not equal) and ~ (1's complement)
5564 operators: probably not what you intended.
5566 =item /%s/ should probably be written as "%s"
5568 (W syntax) You have used a pattern where Perl expected to find a string,
5569 as in the first argument to C<join>. Perl will treat the true or false
5570 result of matching the pattern against $_ as the string, which is
5571 probably not what you had in mind.
5573 =item shutdown() on closed socket %s
5575 (W closed) You tried to do a shutdown on a closed socket. Seems a bit
5578 =item SIG%s handler "%s" not defined
5580 (W signal) The signal handler named in %SIG doesn't, in fact, exist.
5581 Perhaps you put it into the wrong package?
5583 =item Slab leaked from cv %p
5585 (S) If you see this message, then something is seriously wrong with the
5586 internal bookkeeping of op trees. An op tree needed to be freed after
5587 a compilation error, but could not be found, so it was leaked instead.
5589 =item sleep(%u) too large
5591 (W overflow) You called C<sleep> with a number that was larger than
5592 it can reliably handle and C<sleep> probably slept for less time than
5595 =item Slurpy parameter not last
5597 (F) In a subroutine signature, you put something after a slurpy (array or
5598 hash) parameter. The slurpy parameter takes all the available arguments,
5599 so there can't be any left to fill later parameters.
5601 =item Smart matching a non-overloaded object breaks encapsulation
5603 (F) You should not use the C<~~> operator on an object that does not
5604 overload it: Perl refuses to use the object's underlying structure
5605 for the smart match.
5607 =item Smartmatch is experimental
5609 (S experimental::smartmatch) This warning is emitted if you
5610 use the smartmatch (C<~~>) operator. This is currently an experimental
5611 feature, and its details are subject to change in future releases of
5612 Perl. Particularly, its current behavior is noticed for being
5613 unnecessarily complex and unintuitive, and is very likely to be
5616 =item sort is now a reserved word
5618 (F) An ancient error message that almost nobody ever runs into anymore.
5619 But before sort was a keyword, people sometimes used it as a filehandle.
5621 =item Source filters apply only to byte streams
5623 (F) You tried to activate a source filter (usually by loading a
5624 source filter module) within a string passed to C<eval>. This is
5625 not permitted under the C<unicode_eval> feature. Consider using
5626 C<evalbytes> instead. See L<feature>.
5628 =item splice() offset past end of array
5630 (W misc) You attempted to specify an offset that was past the end of
5631 the array passed to splice(). Splicing will instead commence at the
5632 end of the array, rather than past it. If this isn't what you want,
5633 try explicitly pre-extending the array by assigning $#array = $offset.
5634 See L<perlfunc/splice>.
5638 (P) The split was looping infinitely. (Obviously, a split shouldn't
5639 iterate more times than there are characters of input, which is what
5640 happened.) See L<perlfunc/split>.
5642 =item Statement unlikely to be reached
5644 (W exec) You did an exec() with some statement after it other than a
5645 die(). This is almost always an error, because exec() never returns
5646 unless there was a failure. You probably wanted to use system()
5647 instead, which does return. To suppress this warning, put the exec() in
5650 =item "state" subroutine %s can't be in a package
5652 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
5653 sense to try to declare one with a package qualifier on the front.
5655 =item "state %s" used in sort comparison
5657 (W syntax) The package variables $a and $b are used for sort comparisons.
5658 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
5659 sort comparison block, and the variable had earlier been declared as a
5660 lexical variable. Either qualify the sort variable with the package
5661 name, or rename the lexical variable.
5663 =item "state" variable %s can't be in a package
5665 (F) Lexically scoped variables aren't in a package, so it doesn't make
5666 sense to try to declare one with a package qualifier on the front. Use
5667 local() if you want to localize a package variable.
5669 =item stat() on unopened filehandle %s
5671 (W unopened) You tried to use the stat() function on a filehandle that
5672 was either never opened or has since been closed.
5674 =item Strings with code points over 0xFF may not be mapped into in-memory file handles
5676 (W utf8) You tried to open a reference to a scalar for read or append
5677 where the scalar contained code points over 0xFF. In-memory files
5678 model on-disk files and can only contain bytes.
5680 =item Stub found while resolving method "%s" overloading "%s" in package "%s"
5682 (P) Overloading resolution over @ISA tree may be broken by importation
5683 stubs. Stubs should never be implicitly created, but explicit calls to
5684 C<can> may break this.
5686 =item Subroutine "&%s" is not available
5688 (W closure) During compilation, an inner named subroutine or eval is
5689 attempting to capture an outer lexical subroutine that is not currently
5690 available. This can happen for one of two reasons. First, the lexical
5691 subroutine may be declared in an outer anonymous subroutine that has
5692 not yet been created. (Remember that named subs are created at compile
5693 time, while anonymous subs are created at run-time.) For example,
5695 sub { my sub a {...} sub f { \&a } }
5697 At the time that f is created, it can't capture the current "a" sub,
5698 since the anonymous subroutine hasn't been created yet. Conversely, the
5699 following won't give a warning since the anonymous subroutine has by now
5700 been created and is live:
5702 sub { my sub a {...} eval 'sub f { \&a }' }->();
5704 The second situation is caused by an eval accessing a lexical subroutine
5705 that has gone out of scope, for example,
5713 Here, when the '\&a' in the eval is being compiled, f() is not currently
5714 being executed, so its &a is not available for capture.
5716 =item "%s" subroutine &%s masks earlier declaration in same %s
5718 (W misc) A "my" or "state" subroutine has been redeclared in the
5719 current scope or statement, effectively eliminating all access to
5720 the previous instance. This is almost always a typographical error.
5721 Note that the earlier subroutine will still exist until the end of
5722 the scope or until all closure references to it are destroyed.
5724 =item Subroutine %s redefined
5726 (W redefine) You redefined a subroutine. To suppress this warning, say
5729 no warnings 'redefine';
5730 eval "sub name { ... }";
5733 =item Subroutine "%s" will not stay shared
5735 (W closure) An inner (nested) I<named> subroutine is referencing a "my"
5736 subroutine defined in an outer named subroutine.
5738 When the inner subroutine is called, it will see the value of the outer
5739 subroutine's lexical subroutine as it was before and during the *first*
5740 call to the outer subroutine; in this case, after the first call to the
5741 outer subroutine is complete, the inner and outer subroutines will no
5742 longer share a common value for the lexical subroutine. In other words,
5743 it will no longer be shared. This will especially make a difference
5744 if the lexical subroutines accesses lexical variables declared in its
5747 This problem can usually be solved by making the inner subroutine
5748 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
5749 reference lexical subroutines in outer subroutines are created, they
5750 are automatically rebound to the current values of such lexical subs.
5752 =item Substitution loop
5754 (P) The substitution was looping infinitely. (Obviously, a substitution
5755 shouldn't iterate more times than there are characters of input, which
5756 is what happened.) See the discussion of substitution in
5757 L<perlop/"Regexp Quote-Like Operators">.
5759 =item Substitution pattern not terminated
5761 (F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
5762 construct. Remember that bracketing delimiters count nesting level.
5763 Missing the leading C<$> from variable C<$s> may cause this error.
5765 =item Substitution replacement not terminated
5767 (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
5768 construct. Remember that bracketing delimiters count nesting level.
5769 Missing the leading C<$> from variable C<$s> may cause this error.
5771 =item substr outside of string
5773 (W substr)(F) You tried to reference a substr() that pointed outside of
5774 a string. That is, the absolute value of the offset was larger than the
5775 length of the string. See L<perlfunc/substr>. This warning is fatal if
5776 substr is used in an lvalue context (as the left hand side of an
5777 assignment or as a subroutine argument for example).
5779 =item sv_upgrade from type %d down to type %d
5781 (P) Perl tried to force the upgrade of an SV to a type which was actually
5782 inferior to its current type.
5784 =item SWASHNEW didn't return an HV ref
5786 (P) Something went wrong internally when Perl was trying to look up
5789 =item Switch (?(condition)... contains too many branches in regex; marked by
5790 S<<-- HERE> in m/%s/
5792 (F) A (?(condition)if-clause|else-clause) construct can have at most
5793 two branches (the if-clause and the else-clause). If you want one or
5794 both to contain alternation, such as using C<this|that|other>, enclose
5795 it in clustering parentheses:
5797 (?(condition)(?:this|that|other)|else-clause)
5799 The S<<-- HERE> shows whereabouts in the regular expression the problem
5800 was discovered. See L<perlre>.
5802 =item Switch condition not recognized in regex; marked by S<<-- HERE> in
5805 (F) The condition part of a (?(condition)if-clause|else-clause) construct
5806 is not known. The condition must be one of the following:
5808 (1) (2) ... true if 1st, 2nd, etc., capture matched
5809 (<NAME>) ('NAME') true if named capture matched
5810 (?=...) (?<=...) true if subpattern matches
5811 (?!...) (?<!...) true if subpattern fails to match
5812 (?{ CODE }) true if code returns a true value
5813 (R) true if evaluating inside recursion
5814 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
5815 (R&NAME) true if directly inside named capture
5816 (DEFINE) always false; for defining named subpatterns
5818 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5819 discovered. See L<perlre>.
5821 =item Switch (?(condition)... not terminated in regex; marked by
5822 S<<-- HERE> in m/%s/
5824 (F) You omitted to close a (?(condition)...) block somewhere
5825 in the pattern. Add a closing parenthesis in the appropriate
5826 position. See L<perlre>.
5828 =item switching effective %s is not implemented
5830 (F) While under the C<use filetest> pragma, we cannot switch the real
5831 and effective uids or gids.
5835 (F) Probably means you had a syntax error. Common reasons include:
5837 A keyword is misspelled.
5838 A semicolon is missing.
5840 An opening or closing parenthesis is missing.
5841 An opening or closing brace is missing.
5842 A closing quote is missing.
5844 Often there will be another error message associated with the syntax
5845 error giving more information. (Sometimes it helps to turn on B<-w>.)
5846 The error message itself often tells you where it was in the line when
5847 it decided to give up. Sometimes the actual error is several tokens
5848 before this, because Perl is good at understanding random input.
5849 Occasionally the line number may be misleading, and once in a blue moon
5850 the only way to figure out what's triggering the error is to call
5851 C<perl -c> repeatedly, chopping away half the program each time to see
5852 if the error went away. Sort of the cybernetic version of S<20 questions>.
5854 =item syntax error at line %d: '%s' unexpected
5856 (A) You've accidentally run your script through the Bourne shell instead
5857 of Perl. Check the #! line, or manually feed your script into Perl
5860 =item syntax error in file %s at line %d, next 2 tokens "%s"
5862 (F) This error is likely to occur if you run a perl5 script through
5863 a perl4 interpreter, especially if the next 2 tokens are "use strict"
5864 or "my $var" or "our $var".
5866 =item Syntax error in (?[...]) in regex m/%s/
5868 (F) Perl could not figure out what you meant inside this construct; this
5869 notifies you that it is giving up trying.
5873 (F) The final summary message when a C<perl -c> succeeds.
5875 =item sysread() on closed filehandle %s
5877 (W closed) You tried to read from a closed filehandle.
5879 =item sysread() on unopened filehandle %s
5881 (W unopened) You tried to read from a filehandle that was never opened.
5883 =item System V %s is not implemented on this machine
5885 (F) You tried to do something with a function beginning with "sem",
5886 "shm", or "msg" but that System V IPC is not implemented in your
5887 machine. In some machines the functionality can exist but be
5888 unconfigured. Consult your system support.
5890 =item syswrite() on closed filehandle %s
5892 (W closed) The filehandle you're writing to got itself closed sometime
5893 before now. Check your control flow.
5895 =item C<-T> and C<-B> not implemented on filehandles
5897 (F) Perl can't peek at the stdio buffer of filehandles when it doesn't
5898 know about your kind of stdio. You'll have to use a filename instead.
5900 =item Target of goto is too deeply nested
5902 (F) You tried to use C<goto> to reach a label that was too deeply nested
5903 for Perl to reach. Perl is doing you a favor by refusing.
5905 =item telldir() attempted on invalid dirhandle %s
5907 (W io) The dirhandle you tried to telldir() is either closed or not really
5908 a dirhandle. Check your control flow.
5910 =item tell() on unopened filehandle
5912 (W unopened) You tried to use the tell() function on a filehandle that
5913 was either never opened or has since been closed.
5915 =item That use of $[ is unsupported
5917 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
5918 as a compiler directive. You may say only one of
5927 This is to prevent the problem of one module changing the array base out
5928 from under another module inadvertently. See L<perlvar/$[> and L<arybase>.
5930 =item The bitwise feature is experimental
5932 (S experimental::bitwise) This warning is emitted if you use bitwise
5933 operators (C<& | ^ ~ &. |. ^. ~.>) with the "bitwise" feature enabled.
5934 Simply suppress the warning if you want to use the feature, but know
5935 that in doing so you are taking the risk of using an experimental
5936 feature which may change or be removed in a future Perl version:
5938 no warnings "experimental::bitwise";
5939 use feature "bitwise";
5942 =item The crypt() function is unimplemented due to excessive paranoia.
5944 (F) Configure couldn't find the crypt() function on your machine,
5945 probably because your vendor didn't supply it, probably because they
5946 think the U.S. Government thinks it's a secret, or at least that they
5947 will continue to pretend that it is. And if you quote me on that, I
5950 =item The experimental declared_refs feature is not enabled
5952 (F) To declare references to variables, as in C<my \%x>, you must first enable
5955 no warnings "experimental::declared_refs";
5956 use feature "declared_refs";
5958 =item The %s function is unimplemented
5960 (F) The function indicated isn't implemented on this architecture,
5961 according to the probings of Configure.
5963 =item The regex_sets feature is experimental
5965 (S experimental::regex_sets) This warning is emitted if you
5966 use the syntax S<C<(?[ ])>> in a regular expression.
5967 The details of this feature are subject to change.
5968 if you want to use it, but know that in doing so you
5969 are taking the risk of using an experimental feature which may
5970 change in a future Perl version, you can do this to silence the
5973 no warnings "experimental::regex_sets";
5975 =item The signatures feature is experimental
5977 (S experimental::signatures) This warning is emitted if you unwrap a
5978 subroutine's arguments using a signature. Simply suppress the warning
5979 if you want to use the feature, but know that in doing so you are taking
5980 the risk of using an experimental feature which may change or be removed
5981 in a future Perl version:
5983 no warnings "experimental::signatures";
5984 use feature "signatures";
5985 sub foo ($left, $right) { ... }
5987 =item The stat preceding %s wasn't an lstat
5989 (F) It makes no sense to test the current stat buffer for symbolic
5990 linkhood if the last stat that wrote to the stat buffer already went
5991 past the symlink to get to the real file. Use an actual filename
5994 =item The 'unique' attribute may only be applied to 'our' variables
5996 (F) This attribute was never supported on C<my> or C<sub> declarations.
5998 =item This Perl can't reset CRTL environ elements (%s)
6000 =item This Perl can't set CRTL environ elements (%s=%s)
6002 (W internal) Warnings peculiar to VMS. You tried to change or delete an
6003 element of the CRTL's internal environ array, but your copy of Perl
6004 wasn't built with a CRTL that contained the setenv() function. You'll
6005 need to rebuild Perl with a CRTL that does, or redefine
6006 F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
6007 target of the change to
6008 %ENV which produced the warning.
6010 =item This Perl has not been built with support for randomized hash key traversal but something called Perl_hv_rand_set().
6012 (F) Something has attempted to use an internal API call which
6013 depends on Perl being compiled with the default support for randomized hash
6014 key traversal, but this Perl has been compiled without it. You should
6015 report this warning to the relevant upstream party, or recompile perl
6016 with default options.
6018 =item times not implemented
6020 (F) Your version of the C library apparently doesn't do times(). I
6021 suspect you're not running on Unix.
6023 =item "-T" is on the #! line, it must also be used on the command line
6025 (X) The #! line (or local equivalent) in a Perl script contains
6026 the B<-T> option (or the B<-t> option), but Perl was not invoked with
6027 B<-T> in its command line. This is an error because, by the time
6028 Perl discovers a B<-T> in a script, it's too late to properly taint
6029 everything from the environment. So Perl gives up.
6031 If the Perl script is being executed as a command using the #!
6032 mechanism (or its local equivalent), this error can usually be
6033 fixed by editing the #! line so that the B<-%c> option is a part of
6034 Perl's first argument: e.g. change C<perl -n -%c> to C<perl -%c -n>.
6036 If the Perl script is being executed as C<perl scriptname>, then the
6037 B<-%c> option must appear on the command line: C<perl -%c scriptname>.
6039 =item To%s: illegal mapping '%s'
6041 (F) You tried to define a customized To-mapping for lc(), lcfirst,
6042 uc(), or ucfirst() (or their string-inlined versions), but you
6043 specified an illegal mapping.
6044 See L<perlunicode/"User-Defined Character Properties">.
6046 =item Too deeply nested ()-groups
6048 (F) Your template contains ()-groups with a ridiculously deep nesting level.
6050 =item Too few args to syscall
6052 (F) There has to be at least one argument to syscall() to specify the
6053 system call to call, silly dilly.
6055 =item Too few arguments for subroutine
6057 (F) A subroutine using a signature received too few arguments than
6058 required by the signature. The caller of the subroutine is presumably
6061 =item Too late for "-%s" option
6063 (X) The #! line (or local equivalent) in a Perl script contains the
6064 B<-M>, B<-m> or B<-C> option.
6066 In the case of B<-M> and B<-m>, this is an error because those options
6067 are not intended for use inside scripts. Use the C<use> pragma instead.
6069 The B<-C> option only works if it is specified on the command line as
6070 well (with the same sequence of letters or numbers following). Either
6071 specify this option on the command line, or, if your system supports
6072 it, make your script executable and run it directly instead of passing
6075 =item Too late to run %s block
6077 (W void) A CHECK or INIT block is being defined during run time proper,
6078 when the opportunity to run them has already passed. Perhaps you are
6079 loading a file with C<require> or C<do> when you should be using C<use>
6080 instead. Or perhaps you should put the C<require> or C<do> inside a
6083 =item Too many args to syscall
6085 (F) Perl supports a maximum of only 14 args to syscall().
6087 =item Too many arguments for %s
6089 (F) The function requires fewer arguments than you specified.
6091 =item Too many arguments for subroutine
6093 (F) A subroutine using a signature received too many arguments than
6094 required by the signature. The caller of the subroutine is presumably
6100 (A) You've accidentally run your script through B<csh> instead of Perl.
6101 Check the #! line, or manually feed your script into Perl yourself.
6105 (A) You've accidentally run your script through B<csh> instead of Perl.
6106 Check the #! line, or manually feed your script into Perl yourself.
6108 =item Trailing \ in regex m/%s/
6110 (F) The regular expression ends with an unbackslashed backslash.
6111 Backslash it. See L<perlre>.
6113 =item Transliteration pattern not terminated
6115 (F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
6116 or y/// or y[][] construct. Missing the leading C<$> from variables
6117 C<$tr> or C<$y> may cause this error.
6119 =item Transliteration replacement not terminated
6121 (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
6122 y/// or y[][] construct.
6124 =item '%s' trapped by operation mask
6126 (F) You tried to use an operator from a Safe compartment in which it's
6127 disallowed. See L<Safe>.
6129 =item truncate not implemented
6131 (F) Your machine doesn't implement a file truncation mechanism that
6132 Configure knows about.
6134 =item Type of arg %d to &CORE::%s must be %s
6136 (F) The subroutine in question in the CORE package requires its argument
6137 to be a hard reference to data of the specified type. Overloading is
6138 ignored, so a reference to an object that is not the specified type, but
6139 nonetheless has overloading to handle it, will still not be accepted.
6141 =item Type of arg %d to %s must be %s (not %s)
6143 (F) This function requires the argument in that position to be of a
6144 certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
6145 %NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
6146 {EXPR} forms as an explicit dereference. See L<perlref>.
6148 =item umask not implemented
6150 (F) Your machine doesn't implement the umask function and you tried to
6151 use it to restrict permissions for yourself (EXPR & 0700).
6153 =item Unbalanced context: %d more PUSHes than POPs
6155 (S internal) The exit code detected an internal inconsistency in how
6156 many execution contexts were entered and left.
6158 =item Unbalanced saves: %d more saves than restores
6160 (S internal) The exit code detected an internal inconsistency in how
6161 many values were temporarily localized.
6163 =item Unbalanced scopes: %d more ENTERs than LEAVEs
6165 (S internal) The exit code detected an internal inconsistency in how
6166 many blocks were entered and left.
6168 =item Unbalanced string table refcount: (%d) for "%s"
6170 (S internal) On exit, Perl found some strings remaining in the shared
6171 string table used for copy on write and for hash keys. The entries
6172 should have been freed, so this indicates a bug somewhere.
6174 =item Unbalanced tmps: %d more allocs than frees
6176 (S internal) The exit code detected an internal inconsistency in how
6177 many mortal scalars were allocated and freed.
6179 =item Undefined format "%s" called
6181 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6182 another package? See L<perlform>.
6184 =item Undefined sort subroutine "%s" called
6186 (F) The sort comparison routine specified doesn't seem to exist.
6187 Perhaps it's in a different package? See L<perlfunc/sort>.
6189 =item Undefined subroutine &%s called
6191 (F) The subroutine indicated hasn't been defined, or if it was, it has
6192 since been undefined.
6194 =item Undefined subroutine called
6196 (F) The anonymous subroutine you're trying to call hasn't been defined,
6197 or if it was, it has since been undefined.
6199 =item Undefined subroutine in sort
6201 (F) The sort comparison routine specified is declared but doesn't seem
6202 to have been defined yet. See L<perlfunc/sort>.
6204 =item Undefined top format "%s" called
6206 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6207 another package? See L<perlform>.
6209 =item Undefined value assigned to typeglob
6211 (W misc) An undefined value was assigned to a typeglob, a la
6212 C<*foo = undef>. This does nothing. It's possible that you really mean
6215 =item %s: Undefined variable
6217 (A) You've accidentally run your script through B<csh> instead of Perl.
6218 Check the #! line, or manually feed your script into Perl yourself.
6220 =item Unescaped left brace in regex is deprecated here, passed through in
6221 regex; marked by S<<-- HERE> in m/%s/
6223 (D deprecated, regexp) The simple rule to remember, if you want to
6224 match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
6225 regular expression pattern, is to escape each literal instance of it in
6226 some way. Generally easiest is to precede it with a backslash, like
6227 C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
6228 delimiters are also braces, any matching right brace (C<"}">) should
6229 also be escaped to avoid confusing the parser, for example,
6233 Forcing literal C<"{"> characters to be escaped will enable the Perl
6234 language to be extended in various ways in future releases. To avoid
6235 needlessly breaking existing code, the restriction is is not enforced in
6236 contexts where there are unlikely to ever be extensions that could
6237 conflict with the use there of C<"{"> as a literal.
6239 In this release of Perl, some literal uses of C<"{"> are fatal, and some
6240 still just deprecated. This is because of an oversight: some uses of a
6241 literal C<"{"> that should have raised a deprecation warning starting in
6242 v5.20 did not warn until v5.26. By making the already-warned uses fatal
6243 now, some of the planned extensions can be made to the language sooner.
6245 The contexts where no warnings or errors are raised are:
6251 as the first character in a pattern, or following C<"^"> indicating to
6252 anchor the match to the beginning of a line.
6256 as the first character following a C<"|"> indicating alternation.
6260 as the first character in a parenthesized grouping like
6267 as the first character following a quantifier
6274 The text of the message above is duplicated below to allow splain (and
6275 'use diagnostics') to work. Since one is fatal, and one not, they can't
6276 be combined as one message. And since the non-fatal one is temporary,
6277 there's no real need to enhance perldiag to handle this transient case.
6279 =item Unescaped left brace in regex is illegal here in regex;
6280 marked by S<<-- HERE> in m/%s/
6282 (F) The simple rule to remember, if you want to
6283 match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
6284 regular expression pattern, is to escape each literal instance of it in
6285 some way. Generally easiest is to precede it with a backslash, like
6286 C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
6287 delimiters are also braces, any matching right brace (C<"}">) should
6288 also be escaped to avoid confusing the parser, for example,
6292 Forcing literal C<"{"> characters to be escaped will enable the Perl
6293 language to be extended in various ways in future releases. To avoid
6294 needlessly breaking existing code, the restriction is is not enforced in
6295 contexts where there are unlikely to ever be extensions that could
6296 conflict with the use there of C<"{"> as a literal.
6298 In this release of Perl, some literal uses of C<"{"> are fatal, and some
6299 still just deprecated. This is because of an oversight: some uses of a
6300 literal C<"{"> that should have raised a deprecation warning starting in
6301 v5.20 did not warn until v5.26. By making the already-warned uses fatal
6302 now, some of the planned extensions can be made to the language sooner.
6304 The contexts where no warnings or errors are raised are:
6310 as the first character in a pattern, or following C<"^"> indicating to
6311 anchor the match to the beginning of a line.
6315 as the first character following a C<"|"> indicating alternation.
6319 as the first character in a parenthesized grouping like
6326 as the first character following a quantifier
6332 =item unexec of %s into %s failed!
6334 (F) The unexec() routine failed for some reason. See your local FSF
6335 representative, who probably put it there in the first place.
6337 =item Unexpected binary operator '%c' with no preceding operand in regex;
6338 marked by S<<-- HERE> in m/%s/
6340 (F) You had something like this:
6344 where the C<"|"> is a binary operator with an operand on the right, but
6345 no operand on the left.
6347 =item Unexpected character in regex; marked by S<<-- HERE> in m/%s/
6349 (F) You had something like this:
6353 Within C<(?[ ])>, no literal characters are allowed unless they are
6354 within an inner pair of square brackets, like
6358 Another possibility is that you forgot a backslash. Perl isn't smart
6359 enough to figure out what you really meant.
6361 =item Unexpected constant lvalue entersub entry via type/targ %d:%d
6363 (P) When compiling a subroutine call in lvalue context, Perl failed an
6364 internal consistency check. It encountered a malformed op tree.
6366 =item Unexpected exit %u
6368 (S) exit() was called or the script otherwise finished gracefully when
6369 C<PERL_EXIT_WARN> was set in C<PL_exit_flags>.
6371 =item Unexpected exit failure %d
6373 (S) An uncaught die() was called when C<PERL_EXIT_WARN> was set in
6376 =item Unexpected ')' in regex; marked by S<<-- HERE> in m/%s/
6378 (F) You had something like this:
6380 (?[ ( \p{Digit} + ) ])
6382 The C<")"> is out-of-place. Something apparently was supposed to
6383 be combined with the digits, or the C<"+"> shouldn't be there, or
6384 something like that. Perl can't figure out what was intended.
6386 =item Unexpected '(' with no preceding operator in regex; marked by
6387 S<<-- HERE> in m/%s/
6389 (F) You had something like this:
6391 (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
6393 There should be an operator before the C<"(">, as there's
6394 no indication as to how the digits are to be combined
6395 with the characters in the Lao and Thai scripts.
6397 =item Unicode non-character U+%X is not recommended for open interchange
6399 (S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
6400 defined by the Unicode standard to be non-characters. Those
6401 are legal codepoints, but are reserved for internal use; so,
6402 applications shouldn't attempt to exchange them. An application
6403 may not be expecting any of these characters at all, and receiving
6404 them may lead to bugs. If you know what you are doing you can
6405 turn off this warning by C<no warnings 'nonchar';>.
6407 This is not really a "severe" error, but it is supposed to be
6408 raised by default even if warnings are not enabled, and currently
6409 the only way to do that in Perl is to mark it as serious.
6411 =item Unicode surrogate U+%X is illegal in UTF-8
6413 (S surrogate) You had a UTF-16 surrogate in a context where they are
6414 not considered acceptable. These code points, between U+D800 and
6415 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6416 internally allows all unsigned integer code points (up to the size limit
6417 available on your platform), including surrogates. But these can cause
6418 problems when being input or output, which is likely where this message
6419 came from. If you really really know what you are doing you can turn
6420 off this warning by C<no warnings 'surrogate';>.
6422 =item Unknown charname '%s'
6424 (F) The name you used inside C<\N{}> is unknown to Perl. Check the
6425 spelling. You can say C<use charnames ":loose"> to not have to be
6426 so precise about spaces, hyphens, and capitalization on standard Unicode
6427 names. (Any custom aliases that have been created must be specified
6428 exactly, regardless of whether C<:loose> is used or not.) This error may
6429 also happen if the C<\N{}> is not in the scope of the corresponding
6430 C<S<use charnames>>.
6432 =item Unknown charname '' is deprecated
6434 (D deprecated) You had a C<\N{}> with nothing between the braces. This
6435 usage is deprecated, and will be made a syntax error in a future Perl
6440 (P) Perl was about to print an error message in C<$@>, but the C<$@> variable
6441 did not exist, even after an attempt to create it.
6443 =item Unknown open() mode '%s'
6445 (F) The second argument of 3-argument open() is not among the list
6446 of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
6447 C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
6449 =item Unknown PerlIO layer "%s"
6451 (W layer) An attempt was made to push an unknown layer onto the Perl I/O
6452 system. (Layers take care of transforming data between external and
6453 internal representations.) Note that some layers, such as C<mmap>,
6454 are not supported in all environments. If your program didn't
6455 explicitly request the failing operation, it may be the result of the
6456 value of the environment variable PERLIO.
6458 =item Unknown process %x sent message to prime_env_iter: %s
6460 (P) An error peculiar to VMS. Perl was reading values for %ENV before
6461 iterating over it, and someone else stuck a message in the stream of
6462 data Perl expected. Someone's very confused, or perhaps trying to
6463 subvert Perl's population of %ENV for nefarious purposes.
6465 =item Unknown regex modifier "%s"
6467 (F) Alphanumerics immediately following the closing delimiter
6468 of a regular expression pattern are interpreted by Perl as modifier
6469 flags for the regex. One of the ones you specified is invalid. One way
6470 this can happen is if you didn't put in white space between the end of
6471 the regex and a following alphanumeric operator:
6473 if ($a =~ /foo/and $bar == 3) { ... }
6475 The C<"a"> is a valid modifier flag, but the C<"n"> is not, and raises
6476 this error. Likely what was meant instead was:
6478 if ($a =~ /foo/ and $bar == 3) { ... }
6480 =item Unknown "re" subpragma '%s' (known ones are: %s)
6482 (W) You tried to use an unknown subpragma of the "re" pragma.
6484 =item Unknown switch condition (?(...)) in regex; marked by S<<-- HERE> in
6487 (F) The condition part of a (?(condition)if-clause|else-clause) construct
6488 is not known. The condition must be one of the following:
6490 (1) (2) ... true if 1st, 2nd, etc., capture matched
6491 (<NAME>) ('NAME') true if named capture matched
6492 (?=...) (?<=...) true if subpattern matches
6493 (?!...) (?<!...) true if subpattern fails to match
6494 (?{ CODE }) true if code returns a true value
6495 (R) true if evaluating inside recursion
6496 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
6497 (R&NAME) true if directly inside named capture
6498 (DEFINE) always false; for defining named subpatterns
6500 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6501 discovered. See L<perlre>.
6503 =item Unknown Unicode option letter '%c'
6505 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6506 of the C<-C> switch for the list of known options.
6508 =item Unknown Unicode option value %d
6510 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6511 of the C<-C> switch for the list of known options.
6513 =item Unknown verb pattern '%s' in regex; marked by S<<-- HERE> in m/%s/
6515 (F) You either made a typo or have incorrectly put a C<*> quantifier
6516 after an open brace in your pattern. Check the pattern and review
6517 L<perlre> for details on legal verb patterns.
6519 =item Unknown warnings category '%s'
6521 (F) An error issued by the C<warnings> pragma. You specified a warnings
6522 category that is unknown to perl at this point.
6524 Note that if you want to enable a warnings category registered by a
6525 module (e.g. C<use warnings 'File::Find'>), you must have loaded this
6528 =item Unmatched [ in regex; marked by S<<-- HERE> in m/%s/
6530 (F) The brackets around a character class must match. If you wish to
6531 include a closing bracket in a character class, backslash it or put it
6532 first. The S<<-- HERE> shows whereabouts in the regular expression the
6533 problem was discovered. See L<perlre>.
6535 =item Unmatched ( in regex; marked by S<<-- HERE> in m/%s/
6537 =item Unmatched ) in regex; marked by S<<-- HERE> in m/%s/
6539 (F) Unbackslashed parentheses must always be balanced in regular
6540 expressions. If you're a vi user, the % key is valuable for finding
6541 the matching parenthesis. The S<<-- HERE> shows whereabouts in the
6542 regular expression the problem was discovered. See L<perlre>.
6544 =item Unmatched right %s bracket
6546 (F) The lexer counted more closing curly or square brackets than opening
6547 ones, so you're probably missing a matching opening bracket. As a
6548 general rule, you'll find the missing one (so to speak) near the place
6549 you were last editing.
6551 =item Unquoted string "%s" may clash with future reserved word
6553 (W reserved) You used a bareword that might someday be claimed as a
6554 reserved word. It's best to put such a word in quotes, or capitalize it
6555 somehow, or insert an underbar into it. You might also declare it as a
6558 =item Unrecognized character %s; marked by S<<-- HERE> after %s near column
6561 (F) The Perl parser has no idea what to do with the specified character
6562 in your Perl script (or eval) near the specified column. Perhaps you
6563 tried to run a compressed script, a binary program, or a directory as
6566 =item Unrecognized escape \%c in character class in regex; marked by
6567 S<<-- HERE> in m/%s/
6569 (F) You used a backslash-character combination which is not
6570 recognized by Perl inside character classes. This is a fatal
6571 error when the character class is used within C<(?[ ])>.
6573 =item Unrecognized escape \%c in character class passed through in regex;
6574 marked by S<<-- HERE> in m/%s/
6576 (W regexp) You used a backslash-character combination which is not
6577 recognized by Perl inside character classes. The character was
6578 understood literally, but this may change in a future version of Perl.
6579 The S<<-- HERE> shows whereabouts in the regular expression the
6580 escape was discovered.
6582 =item Unrecognized escape \%c passed through
6584 (W misc) You used a backslash-character combination which is not
6585 recognized by Perl. The character was understood literally, but this may
6586 change in a future version of Perl.
6588 =item Unrecognized escape \%s passed through in regex; marked by
6589 S<<-- HERE> in m/%s/
6591 (W regexp) You used a backslash-character combination which is not
6592 recognized by Perl. The character(s) were understood literally, but
6593 this may change in a future version of Perl. The S<<-- HERE> shows
6594 whereabouts in the regular expression the escape was discovered.
6596 =item Unrecognized signal name "%s"
6598 (F) You specified a signal name to the kill() function that was not
6599 recognized. Say C<kill -l> in your shell to see the valid signal names
6602 =item Unrecognized switch: -%s (-h will show valid options)
6604 (F) You specified an illegal option to Perl. Don't do that. (If you
6605 think you didn't do that, check the #! line to see if it's supplying the
6606 bad switch on your behalf.)
6608 =item Unsuccessful %s on filename containing newline
6610 (W newline) A file operation was attempted on a filename, and that
6611 operation failed, PROBABLY because the filename contained a newline,
6612 PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
6614 =item Unsupported directory function "%s" called
6616 (F) Your machine doesn't support opendir() and readdir().
6618 =item Unsupported function %s
6620 (F) This machine doesn't implement the indicated function, apparently.
6621 At least, Configure doesn't think so.
6623 =item Unsupported function fork
6625 (F) Your version of executable does not support forking.
6627 Note that under some systems, like OS/2, there may be different flavors
6628 of Perl executables, some of which may support fork, some not. Try
6629 changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
6631 =item Unsupported script encoding %s
6633 (F) Your program file begins with a Unicode Byte Order Mark (BOM) which
6634 declares it to be in a Unicode encoding that Perl cannot read.
6636 =item Unsupported socket function "%s" called
6638 (F) Your machine doesn't support the Berkeley socket mechanism, or at
6639 least that's what Configure thought.
6641 =item Unterminated attribute list
6643 (F) The lexer found something other than a simple identifier at the
6644 start of an attribute, and it wasn't a semicolon or the start of a
6645 block. Perhaps you terminated the parameter list of the previous
6646 attribute too soon. See L<attributes>.
6648 =item Unterminated attribute parameter in attribute list
6650 (F) The lexer saw an opening (left) parenthesis character while parsing
6651 an attribute list, but the matching closing (right) parenthesis
6652 character was not found. You may need to add (or remove) a backslash
6653 character to get your parentheses to balance. See L<attributes>.
6655 =item Unterminated compressed integer
6657 (F) An argument to unpack("w",...) was incompatible with the BER
6658 compressed integer format and could not be converted to an integer.
6659 See L<perlfunc/pack>.
6661 =item Unterminated delimiter for here document
6663 (F) This message occurs when a here document label has an initial
6664 quotation mark but the final quotation mark is missing. Perhaps
6673 =item Unterminated \g... pattern in regex; marked by S<<-- HERE> in m/%s/
6675 =item Unterminated \g{...} pattern in regex; marked by S<<-- HERE> in m/%s/
6677 (F) In a regular expression, you had a C<\g> that wasn't followed by a
6678 proper group reference. In the case of C<\g{>, the closing brace is
6679 missing; otherwise the C<\g> must be followed by an integer. Fix the
6682 =item Unterminated <> operator
6684 (F) The lexer saw a left angle bracket in a place where it was expecting
6685 a term, so it's looking for the corresponding right angle bracket, and
6686 not finding it. Chances are you left some needed parentheses out
6687 earlier in the line, and you really meant a "less than".
6689 =item Unterminated verb pattern argument in regex; marked by S<<-- HERE> in
6692 (F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
6693 the pattern with a C<)>. Fix the pattern and retry.
6695 =item Unterminated verb pattern in regex; marked by S<<-- HERE> in m/%s/
6697 (F) You used a pattern of the form C<(*VERB)> but did not terminate
6698 the pattern with a C<)>. Fix the pattern and retry.
6700 =item untie attempted while %d inner references still exist
6702 (W untie) A copy of the object returned from C<tie> (or C<tied>) was
6703 still valid when C<untie> was called.
6705 =item Usage: POSIX::%s(%s)
6707 (F) You called a POSIX function with incorrect arguments.
6708 See L<POSIX/FUNCTIONS> for more information.
6710 =item Usage: Win32::%s(%s)
6712 (F) You called a Win32 function with incorrect arguments.
6713 See L<Win32> for more information.
6715 =item $[ used in %s (did you mean $] ?)
6717 (W syntax) You used C<$[> in a comparison, such as:
6723 You probably meant to use C<$]> instead. C<$[> is the base for indexing
6724 arrays. C<$]> is the Perl version number in decimal.
6726 =item Use "%s" instead of "%s"
6728 (F) The second listed construct is no longer legal. Use the first one
6731 =item Useless assignment to a temporary
6733 (W misc) You assigned to an lvalue subroutine, but what
6734 the subroutine returned was a temporary scalar about to
6735 be discarded, so the assignment had no effect.
6737 =item Useless (?-%s) - don't use /%s modifier in regex; marked by
6738 S<<-- HERE> in m/%s/
6740 (W regexp) You have used an internal modifier such as (?-o) that has no
6741 meaning unless removed from the entire regexp:
6743 if ($string =~ /(?-o)$pattern/o) { ... }
6747 if ($string =~ /$pattern/) { ... }
6749 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6750 discovered. See L<perlre>.
6752 =item Useless localization of %s
6754 (W syntax) The localization of lvalues such as C<local($x=10)> is legal,
6755 but in fact the local() currently has no effect. This may change at
6756 some point in the future, but in the meantime such code is discouraged.
6758 =item Useless (?%s) - use /%s modifier in regex; marked by S<<-- HERE> in
6761 (W regexp) You have used an internal modifier such as (?o) that has no
6762 meaning unless applied to the entire regexp:
6764 if ($string =~ /(?o)$pattern/) { ... }
6768 if ($string =~ /$pattern/o) { ... }
6770 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6771 discovered. See L<perlre>.
6773 =item Useless use of attribute "const"
6775 (W misc) The C<const> attribute has no effect except
6776 on anonymous closure prototypes. You applied it to
6777 a subroutine via L<attributes.pm|attributes>. This is only useful
6778 inside an attribute handler for an anonymous subroutine.
6780 =item Useless use of /d modifier in transliteration operator
6782 (W misc) You have used the /d modifier where the searchlist has the
6783 same length as the replacelist. See L<perlop> for more information
6784 about the /d modifier.
6786 =item Useless use of \E
6788 (W misc) You have a \E in a double-quotish string without a C<\U>,
6789 C<\L> or C<\Q> preceding it.
6791 =item Useless use of greediness modifier '%c' in regex; marked by S<<-- HERE> in m/%s/
6793 (W regexp) You specified something like these:
6798 The C<"?"> and C<"+"> don't have any effect, as they modify whether to
6799 match more or fewer when there is a choice, and by specifying to match
6800 exactly a given numer, there is no room left for a choice.
6802 =item Useless use of %s in void context
6804 (W void) You did something without a side effect in a context that does
6805 nothing with the return value, such as a statement that doesn't return a
6806 value from a block, or the left side of a scalar comma operator. Very
6807 often this points not to stupidity on your part, but a failure of Perl
6808 to parse your program the way you thought it would. For example, you'd
6809 get this if you mixed up your C precedence with Python precedence and
6814 when you meant to say
6816 ($one, $two) = (1, 2);
6818 Another common error is to use ordinary parentheses to construct a list
6819 reference when you should be using square or curly brackets, for
6824 when you should have said
6828 The square brackets explicitly turn a list value into a scalar value,
6829 while parentheses do not. So when a parenthesized list is evaluated in
6830 a scalar context, the comma is treated like C's comma operator, which
6831 throws away the left argument, which is not what you want. See
6832 L<perlref> for more on this.
6834 This warning will not be issued for numerical constants equal to 0 or 1
6835 since they are often used in statements like
6837 1 while sub_with_side_effects();
6839 String constants that would normally evaluate to 0 or 1 are warned
6842 =item Useless use of (?-p) in regex; marked by S<<-- HERE> in m/%s/
6844 (W regexp) The C<p> modifier cannot be turned off once set. Trying to do
6847 =item Useless use of "re" pragma
6849 (W) You did C<use re;> without any arguments. That isn't very useful.
6851 =item Useless use of sort in scalar context
6853 (W void) You used sort in scalar context, as in :
6857 This is not very useful, and perl currently optimizes this away.
6859 =item Useless use of %s with no values
6861 (W syntax) You used the push() or unshift() function with no arguments
6862 apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
6863 usually have any effect on the array, so is completely useless. It's
6864 possible in principle that push(@tied_array) could have some effect
6865 if the array is tied to a class which implements a PUSH method. If so,
6866 you can write it as C<push(@tied_array,())> to avoid this warning.
6868 =item "use" not allowed in expression
6870 (F) The "use" keyword is recognized and executed at compile time, and
6871 returns no useful value. See L<perlmod>.
6873 =item Use of assignment to $[ is deprecated
6875 (D deprecated) The C<$[> variable (index of the first element in an array)
6876 is deprecated. See L<perlvar/"$[">.
6878 =item Use of bare << to mean <<"" is deprecated
6880 (D deprecated) You are now encouraged to use the explicitly quoted
6881 form if you wish to use an empty line as the terminator of the
6884 =item Use of /c modifier is meaningless in s///
6886 (W regexp) You used the /c modifier in a substitution. The /c
6887 modifier is not presently meaningful in substitutions.
6889 =item Use of /c modifier is meaningless without /g
6891 (W regexp) You used the /c modifier with a regex operand, but didn't
6892 use the /g modifier. Currently, /c is meaningful only when /g is
6893 used. (This may change in the future.)
6895 =item Use of code point 0x%s is deprecated; the permissible max is 0x%s
6897 (D deprecated) You used a code point that will not be allowed in a
6898 future perl version, because it is too large. Unicode only allows code
6899 points up to 0x10FFFF, but Perl allows much larger ones. However, the
6900 largest possible ones break the perl interpreter in some constructs,
6901 including causing it to hang in a few cases. The known problem areas
6902 are in C<tr///>, regular expression pattern matching using quantifiers,
6903 as quote delimiters in C<qI<X>...I<X>> (where I<X> is the C<chr()> of a large
6904 code point), and as the upper limits in loops.
6905 There may be other breakages as well. If you get this warning, and
6906 things aren't working correctly, you probably have found one of these.
6908 If your code is to run on various platforms, keep in mind that the upper
6909 limit depends on the platform. It is much larger on 64-bit word sizes
6912 =item Use of comma-less variable list is deprecated
6914 (D deprecated) The values you give to a format should be
6915 separated by commas, not just aligned on a line.
6917 =item Use of each() on hash after insertion without resetting hash iterator results in undefined behavior
6919 (S internal) The behavior of C<each()> after insertion is undefined;
6920 it may skip items, or visit items more than once. Consider using
6921 C<keys()> instead of C<each()>.
6923 =item Use of := for an empty attribute list is not allowed
6925 (F) The construction C<my $x := 42> used to parse as equivalent to
6926 C<my $x : = 42> (applying an empty attribute list to C<$x>).
6927 This construct was deprecated in 5.12.0, and has now been made a syntax
6928 error, so C<:=> can be reclaimed as a new operator in the future.
6930 If you need an empty attribute list, for example in a code generator, add
6931 a space before the C<=>.
6933 =item Use of %s for non-UTF-8 locale is wrong. Assuming a UTF-8 locale
6935 (W locale) You are matching a regular expression using locale rules,
6936 and the specified construct was encountered. This construct is only
6937 valid for UTF-8 locales, which the current locale isn't. This doesn't
6938 make sense. Perl will continue, assuming a Unicode (UTF-8) locale, but
6939 the results are likely to be wrong.
6941 =item Use of freed value in iteration
6943 (F) Perhaps you modified the iterated array within the loop?
6944 This error is typically caused by code like the following:
6947 @a = () for (1,2,@a);
6949 You are not supposed to modify arrays while they are being iterated over.
6950 For speed and efficiency reasons, Perl internally does not do full
6951 reference-counting of iterated items, hence deleting such an item in the
6952 middle of an iteration causes Perl to see a freed value.
6954 =item Use of *glob{FILEHANDLE} is deprecated
6956 (D deprecated) You are now encouraged to use the shorter *glob{IO} form
6957 to access the filehandle slot within a typeglob.
6959 =item Use of /g modifier is meaningless in split
6961 (W regexp) You used the /g modifier on the pattern for a C<split>
6962 operator. Since C<split> always tries to match the pattern
6963 repeatedly, the C</g> has no effect.
6965 =item Use of "goto" to jump into a construct is deprecated
6967 (D deprecated) Using C<goto> to jump from an outer scope into an inner
6968 scope is deprecated and should be avoided.
6970 =item Use of inherited AUTOLOAD for non-method %s() is deprecated
6972 (D deprecated) As an (ahem) accidental feature, C<AUTOLOAD>
6973 subroutines are looked up as methods (using the C<@ISA> hierarchy)
6974 even when the subroutines to be autoloaded were called as plain
6975 functions (e.g. C<Foo::bar()>), not as methods (e.g. C<< Foo->bar() >> or
6976 C<< $obj->bar() >>).
6978 This bug will be rectified in future by using method lookup only for
6979 methods' C<AUTOLOAD>s. However, there is a significant base of existing
6980 code that may be using the old behavior. So, as an interim step, Perl
6981 currently issues an optional warning when non-methods use inherited
6984 The simple rule is: Inheritance will not work when autoloading
6985 non-methods. The simple fix for old code is: In any module that used
6986 to depend on inheriting C<AUTOLOAD> for non-methods from a base class
6987 named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
6990 In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
6991 you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
6992 C<use AutoLoader 'AUTOLOAD';>.
6994 =item Use of %s in printf format not supported
6996 (F) You attempted to use a feature of printf that is accessible from
6997 only C. This usually means there's a better way to do it in Perl.
6999 =item Use of %s is deprecated
7001 (D deprecated) The construct indicated is no longer recommended for use,
7002 generally because there's a better way to do it, and also because the
7003 old way has bad side effects.
7005 =item Use of -l on filehandle%s
7007 (W io) A filehandle represents an opened file, and when you opened the file
7008 it already went past any symlink you are presumably trying to look for.
7009 The operation returned C<undef>. Use a filename instead.
7011 =item Use of %s on a handle without * is deprecated
7013 (D deprecated) You used C<tie>, C<tied> or C<untie> on a scalar but that scalar
7014 happens to hold a typeglob, which means its filehandle will be tied. If
7015 you mean to tie a handle, use an explicit * as in C<tie *$handle>.
7017 This was a long-standing bug that was removed in Perl 5.16, as there was
7018 no way to tie the scalar itself when it held a typeglob, and no way to
7019 untie a scalar that had had a typeglob assigned to it. If you see this
7020 message, you must be using an older version.
7022 =item Use of reference "%s" as array index
7024 (W misc) You tried to use a reference as an array index; this probably
7025 isn't what you mean, because references in numerical context tend
7026 to be huge numbers, and so usually indicates programmer error.
7028 If you really do mean it, explicitly numify your reference, like so:
7029 C<$array[0+$ref]>. This warning is not given for overloaded objects,
7030 however, because you can overload the numification and stringification
7031 operators and then you presumably know what you are doing.
7033 =item Use of state $_ is experimental
7035 (S experimental::lexical_topic) Lexical $_ is an experimental feature and
7036 its behavior may change or even be removed in any future release of perl.
7037 See the explanation under L<perlvar/$_>.
7039 =item Use of strings with code points over 0xFF as arguments to %s
7040 operator is deprecated
7042 (D deprecated) You tried to use one of the string bitwise operators
7043 (C<&> or C<|> or C<^> or C<~>) on a string containing a code point over
7044 0xFF. The string bitwise operators treat their operands as strings of
7045 bytes, and values beyond 0xFF are nonsensical in this context.
7047 =item Use of tainted arguments in %s is deprecated
7049 (W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
7050 arguments and at least one of them is tainted. This used to be allowed
7051 but will become a fatal error in a future version of perl. Untaint your
7052 arguments. See L<perlsec>.
7054 =item Use of uninitialized value%s
7056 (W uninitialized) An undefined value was used as if it were already
7057 defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
7058 To suppress this warning assign a defined value to your variables.
7060 To help you figure out what was undefined, perl will try to tell you
7061 the name of the variable (if any) that was undefined. In some cases
7062 it cannot do this, so it also tells you what operation you used the
7063 undefined value in. Note, however, that perl optimizes your program
7064 and the operation displayed in the warning may not necessarily appear
7065 literally in your program. For example, C<"that $foo"> is usually
7066 optimized into C<"that " . $foo>, and the warning will refer to the
7067 C<concatenation (.)> operator, even though there is no C<.> in
7070 =item "use re 'strict'" is experimental
7072 (S experimental::re_strict) The things that are different when a regular
7073 expression pattern is compiled under C<'strict'> are subject to change
7074 in future Perl releases in incompatible ways. This means that a pattern
7075 that compiles today may not in a future Perl release. This warning is
7076 to alert you to that risk.
7078 =item Use \x{...} for more than two hex characters in regex; marked by
7079 S<<-- HERE> in m/%s/
7081 (F) In a regular expression, you said something like
7085 Perl isn't sure if you meant this
7089 or if you meant this
7091 (?[ [ \x{BE} E F ] ])
7093 You need to add either braces or blanks to disambiguate.
7095 =item Using just the first character returned by \N{} in character class in
7096 regex; marked by S<<-- HERE> in m/%s/
7098 (W regexp) Named Unicode character escapes C<(\N{...})> may return
7099 a multi-character sequence. Even though a character class is
7100 supposed to match just one character of input, perl will match
7101 the whole thing correctly, except when the class is inverted
7102 (C<[^...]>), or the escape is the beginning or final end point of
7103 a range. For these, what should happen isn't clear at all. In
7104 these circumstances, Perl discards all but the first character
7105 of the returned sequence, which is not likely what you want.
7107 =item Using /u for '%s' instead of /%s in regex; marked by S<<-- HERE> in m/%s/
7109 (W regexp) You used a Unicode boundary (C<\b{...}> or C<\B{...}>) in a
7110 portion of a regular expression where the character set modifiers C</a>
7111 or C</aa> are in effect. These two modifiers indicate an ASCII
7112 interpretation, and this doesn't make sense for a Unicode defintion.
7113 The generated regular expression will compile so that the boundary uses
7114 all of Unicode. No other portion of the regular expression is affected.
7116 =item Using !~ with %s doesn't make sense
7118 (F) Using the C<!~> operator with C<s///r>, C<tr///r> or C<y///r> is
7119 currently reserved for future use, as the exact behavior has not
7120 been decided. (Simply returning the boolean opposite of the
7121 modified string is usually not particularly useful.)
7123 =item UTF-16 surrogate U+%X
7125 (S surrogate) You had a UTF-16 surrogate in a context where they are
7126 not considered acceptable. These code points, between U+D800 and
7127 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
7128 internally allows all unsigned integer code points (up to the size limit
7129 available on your platform), including surrogates. But these can cause
7130 problems when being input or output, which is likely where this message
7131 came from. If you really really know what you are doing you can turn
7132 off this warning by C<no warnings 'surrogate';>.
7134 =item Value of %s can be "0"; test with defined()
7136 (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
7137 C<each()>, or C<readdir()> as a boolean value. Each of these constructs
7138 can return a value of "0"; that would make the conditional expression
7139 false, which is probably not what you intended. When using these
7140 constructs in conditional expressions, test their values with the
7141 C<defined> operator.
7143 =item Value of CLI symbol "%s" too long
7145 (W misc) A warning peculiar to VMS. Perl tried to read the value of an
7146 %ENV element from a CLI symbol table, and found a resultant string
7147 longer than 1024 characters. The return value has been truncated to
7150 =item Variable "%s" is not available
7152 (W closure) During compilation, an inner named subroutine or eval is
7153 attempting to capture an outer lexical that is not currently available.
7154 This can happen for one of two reasons. First, the outer lexical may be
7155 declared in an outer anonymous subroutine that has not yet been created.
7156 (Remember that named subs are created at compile time, while anonymous
7157 subs are created at run-time.) For example,
7159 sub { my $a; sub f { $a } }
7161 At the time that f is created, it can't capture the current value of $a,
7162 since the anonymous subroutine hasn't been created yet. Conversely,
7163 the following won't give a warning since the anonymous subroutine has by
7164 now been created and is live:
7166 sub { my $a; eval 'sub f { $a }' }->();
7168 The second situation is caused by an eval accessing a variable that has
7169 gone out of scope, for example,
7177 Here, when the '$a' in the eval is being compiled, f() is not currently
7178 being executed, so its $a is not available for capture.
7180 =item Variable "%s" is not imported%s
7182 (S misc) With "use strict" in effect, you referred to a global variable
7183 that you apparently thought was imported from another module, because
7184 something else of the same name (usually a subroutine) is exported by
7185 that module. It usually means you put the wrong funny character on the
7186 front of your variable.
7188 =item Variable length lookbehind not implemented in regex m/%s/
7190 (F) Lookbehind is allowed only for subexpressions whose length is fixed and
7191 known at compile time. For positive lookbehind, you can use the C<\K>
7192 regex construct as a way to get the equivalent functionality. See
7193 L<perlre/(?<=pattern) \K>.
7195 There are non-obvious Unicode rules under C</i> that can match variably,
7196 but which you might not think could. For example, the substring C<"ss">
7197 can match the single character LATIN SMALL LETTER SHARP S. There are
7198 other sequences of ASCII characters that can match single ligature
7199 characters, such as LATIN SMALL LIGATURE FFI matching C<qr/ffi/i>.
7200 Starting in Perl v5.16, if you only care about ASCII matches, adding the
7201 C</aa> modifier to the regex will exclude all these non-obvious matches,
7202 thus getting rid of this message. You can also say C<S<use re qw(/aa)>>
7203 to apply C</aa> to all regular expressions compiled within its scope.
7206 =item "%s" variable %s masks earlier declaration in same %s
7208 (W misc) A "my", "our" or "state" variable has been redeclared in the
7209 current scope or statement, effectively eliminating all access to the
7210 previous instance. This is almost always a typographical error. Note
7211 that the earlier variable will still exist until the end of the scope
7212 or until all closure references to it are destroyed.
7214 =item Variable syntax
7216 (A) You've accidentally run your script through B<csh> instead
7217 of Perl. Check the #! line, or manually feed your script into
7220 =item Variable "%s" will not stay shared
7222 (W closure) An inner (nested) I<named> subroutine is referencing a
7223 lexical variable defined in an outer named subroutine.
7225 When the inner subroutine is called, it will see the value of
7226 the outer subroutine's variable as it was before and during the *first*
7227 call to the outer subroutine; in this case, after the first call to the
7228 outer subroutine is complete, the inner and outer subroutines will no
7229 longer share a common value for the variable. In other words, the
7230 variable will no longer be shared.
7232 This problem can usually be solved by making the inner subroutine
7233 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
7234 reference variables in outer subroutines are created, they
7235 are automatically rebound to the current values of such variables.
7237 =item vector argument not supported with alpha versions
7239 (S printf) The %vd (s)printf format does not support version objects
7242 =item Verb pattern '%s' has a mandatory argument in regex; marked by
7243 S<<-- HERE> in m/%s/
7245 (F) You used a verb pattern that requires an argument. Supply an
7246 argument or check that you are using the right verb.
7248 =item Verb pattern '%s' may not have an argument in regex; marked by
7249 S<<-- HERE> in m/%s/
7251 (F) You used a verb pattern that is not allowed an argument. Remove the
7252 argument or check that you are using the right verb.
7254 =item Version control conflict marker
7256 (F) The parser found a line starting with C<E<lt><<<<<<>,
7257 C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
7258 version control system to mark conflicts after a failed merge operation.
7260 =item Version number must be a constant number
7262 (P) The attempt to translate a C<use Module n.n LIST> statement into
7263 its equivalent C<BEGIN> block found an internal inconsistency with
7266 =item Version string '%s' contains invalid data; ignoring: '%s'
7268 (W misc) The version string contains invalid characters at the end, which
7271 =item Warning: something's wrong
7273 (W) You passed warn() an empty string (the equivalent of C<warn "">) or
7274 you called it with no args and C<$@> was empty.
7276 =item Warning: unable to close filehandle %s properly
7278 (S) The implicit close() done by an open() got an error indication on
7279 the close(). This usually indicates your file system ran out of disk
7282 =item Warning: unable to close filehandle properly: %s
7284 =item Warning: unable to close filehandle %s properly: %s
7286 (S io) There were errors during the implicit close() done on a filehandle
7287 when its reference count reached zero while it was still open, e.g.:
7290 open my $fh, '>', $file or die "open: '$file': $!\n";
7291 print $fh $data or die "print: $!";
7292 } # implicit close here
7294 Because various errors may only be detected by close() (e.g. buffering could
7295 allow the C<print> in this example to return true even when the disk is full),
7296 it is dangerous to ignore its result. So when it happens implicitly, perl
7297 will signal errors by warning.
7299 B<Prior to version 5.22.0, perl ignored such errors>, so the common idiom shown
7300 above was liable to cause B<silent data loss>.
7302 =item Warning: Use of "%s" without parentheses is ambiguous
7304 (S ambiguous) You wrote a unary operator followed by something that
7305 looks like a binary operator that could also have been interpreted as a
7306 term or unary operator. For instance, if you know that the rand
7307 function has a default argument of 1.0, and you write
7311 you may THINK you wrote the same thing as
7315 but in actual fact, you got
7319 So put in parentheses to say what you really mean.
7321 =item when is experimental
7323 (S experimental::smartmatch) C<when> depends on smartmatch, which is
7324 experimental. Additionally, it has several special cases that may
7325 not be immediately obvious, and their behavior may change or
7326 even be removed in any future release of perl. See the explanation
7327 under L<perlsyn/Experimental Details on given and when>.
7329 =item Wide character in %s
7331 (S utf8) Perl met a wide character (>255) when it wasn't expecting
7332 one. This warning is by default on for I/O (like print). The easiest
7333 way to quiet this warning is simply to add the C<:utf8> layer to the
7334 output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
7335 warning is to add C<no warnings 'utf8';> but that is often closer to
7336 cheating. In general, you are supposed to explicitly mark the
7337 filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
7339 =item Wide character (U+%X) in %s
7341 (W locale) While in a single-byte locale (I<i.e.>, a non-UTF-8
7342 one), a multi-byte character was encountered. Perl considers this
7343 character to be the specified Unicode code point. Combining non-UTF-8
7344 locales and Unicode is dangerous. Almost certainly some characters
7345 will have two different representations. For example, in the ISO 8859-7
7346 (Greek) locale, the code point 0xC3 represents a Capital Gamma. But so
7347 also does 0x393. This will make string comparisons unreliable.
7349 You likely need to figure out how this multi-byte character got mixed up
7350 with your single-byte locale (or perhaps you thought you had a UTF-8
7351 locale, but Perl disagrees).
7353 =item Within []-length '%c' not allowed
7355 (F) The count in the (un)pack template may be replaced by C<[TEMPLATE]>
7356 only if C<TEMPLATE> always matches the same amount of packed bytes that
7357 can be determined from the template alone. This is not possible if
7358 it contains any of the codes @, /, U, u, w or a *-length. Redesign
7361 =item %s() with negative argument
7363 (S misc) Certain operations make no sense with negative arguments.
7364 Warning is given and the operation is not done.
7366 =item write() on closed filehandle %s
7368 (W closed) The filehandle you're writing to got itself closed sometime
7369 before now. Check your control flow.
7371 =item %s "\x%X" does not map to Unicode
7373 (S utf8) When reading in different encodings, Perl tries to
7374 map everything into Unicode characters. The bytes you read
7375 in are not legal in this encoding. For example
7377 utf8 "\xE4" does not map to Unicode
7379 if you try to read in the a-diaereses Latin-1 as UTF-8.
7381 =item 'X' outside of string
7383 (F) You had a (un)pack template that specified a relative position before
7384 the beginning of the string being (un)packed. See L<perlfunc/pack>.
7386 =item 'x' outside of string in unpack
7388 (F) You had a pack template that specified a relative position after
7389 the end of the string being unpacked. See L<perlfunc/pack>.
7391 =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
7393 (F) And you probably never will, because you probably don't have the
7394 sources to your kernel, and your vendor probably doesn't give a rip
7395 about what you want. Your best bet is to put a setuid C wrapper around
7398 =item You need to quote "%s"
7400 (W syntax) You assigned a bareword as a signal handler name.
7401 Unfortunately, you already have a subroutine of that name declared,
7402 which means that Perl 5 will try to call the subroutine when the
7403 assignment is executed, which is probably not what you want. (If it IS
7404 what you want, put an & in front.)
7406 =item Your random numbers are not that random
7408 (F) When trying to initialize the random seed for hashes, Perl could
7409 not get any randomness out of your system. This usually indicates
7410 Something Very Wrong.
7412 =item Zero length \N{} in regex; marked by S<<-- HERE> in m/%s/
7414 (F) Named Unicode character escapes (C<\N{...}>) may return a zero-length
7415 sequence. Such an escape was used in an extended character class, i.e.
7416 C<(?[...])>, or under C<use re 'strict'>, which is not permitted. Check
7417 that the correct escape has been used, and the correct charnames handler
7418 is in scope. The S<<-- HERE> shows whereabouts in the regular
7419 expression the problem was discovered.
7425 L<warnings>, L<diagnostics>.