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 Ambiguous call resolved as CORE::%s(), qualify as such or use &
77 (W ambiguous) A subroutine you have declared has the same name as a Perl
78 keyword, and you have used the name without qualification for calling
79 one or the other. Perl decided to call the builtin because the
80 subroutine is not imported.
82 To force interpretation as a subroutine call, either put an ampersand
83 before the subroutine name, or qualify the name with its package.
84 Alternatively, you can import the subroutine (or pretend that it's
85 imported with the C<use subs> pragma).
87 To silently interpret it as the Perl operator, use the C<CORE::> prefix
88 on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
89 to be an object method (see L<perlsub/"Subroutine Attributes"> or
92 =item Ambiguous range in transliteration operator
94 (F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
95 all. To include a C<-> character in a transliteration, put it either
96 first or last. (In the past, C<tr/a-z-0//> was synonymous with
97 C<tr/a-y//>, which was probably not what you would have expected.)
99 =item Ambiguous use of %s resolved as %s
101 (S ambiguous) You said something that may not be interpreted the way
102 you thought. Normally it's pretty easy to disambiguate it by supplying
103 a missing quote, operator, parenthesis pair or declaration.
105 =item Ambiguous use of -%s resolved as -&%s()
107 (S ambiguous) You wrote something like C<-foo>, which might be the
108 string C<"-foo">, or a call to the function C<foo>, negated. If you meant
109 the string, just write C<"-foo">. If you meant the function call,
112 =item Ambiguous use of %c resolved as operator %c
114 (S ambiguous) C<%>, C<&>, and C<*> are both infix operators (modulus,
115 bitwise and, and multiplication) I<and> initial special characters
116 (denoting hashes, subroutines and typeglobs), and you said something
117 like C<*foo * foo> that might be interpreted as either of them. We
118 assumed you meant the infix operator, but please try to make it more
119 clear -- in the example given, you might write C<*foo * foo()> if you
120 really meant to multiply a glob by the result of calling a function.
122 =item Ambiguous use of %c{%s} resolved to %c%s
124 (W ambiguous) You wrote something like C<@{foo}>, which might be
125 asking for the variable C<@foo>, or it might be calling a function
126 named foo, and dereferencing it as an array reference. If you wanted
127 the variable, you can just write C<@foo>. If you wanted to call the
128 function, write C<@{foo()}> ... or you could just not have a variable
129 and a function with the same name, and save yourself a lot of trouble.
131 =item Ambiguous use of %c{%s[...]} resolved to %c%s[...]
133 =item Ambiguous use of %c{%s{...}} resolved to %c%s{...}
135 (W ambiguous) You wrote something like C<${foo[2]}> (where foo represents
136 the name of a Perl keyword), which might be looking for element number
137 2 of the array named C<@foo>, in which case please write C<$foo[2]>, or you
138 might have meant to pass an anonymous arrayref to the function named
139 foo, and then do a scalar deref on the value it returns. If you meant
140 that, write C<${foo([2])}>.
142 In regular expressions, the C<${foo[2]}> syntax is sometimes necessary
143 to disambiguate between array subscripts and character classes.
144 C</$length[2345]/>, for instance, will be interpreted as C<$length> followed
145 by the character class C<[2345]>. If an array subscript is what you
146 want, you can avoid the warning by changing C</${length[2345]}/> to the
147 unsightly C</${\$length[2345]}/>, by renaming your array to something
148 that does not coincide with a built-in keyword, or by simply turning
149 off warnings with C<no warnings 'ambiguous';>.
151 =item '|' and '<' may not both be specified on command line
153 (F) An error peculiar to VMS. Perl does its own command line
154 redirection, and found that STDIN was a pipe, and that you also tried to
155 redirect STDIN using '<'. Only one STDIN stream to a customer, please.
157 =item '|' and '>' may not both be specified on command line
159 (F) An error peculiar to VMS. Perl does its own command line
160 redirection, and thinks you tried to redirect stdout both to a file and
161 into a pipe to another command. You need to choose one or the other,
162 though nothing's stopping you from piping into a program or Perl script
163 which 'splits' output into two streams, such as
165 open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
172 =item Applying %s to %s will act on scalar(%s)
174 (W misc) The pattern match (C<//>), substitution (C<s///>), and
175 transliteration (C<tr///>) operators work on scalar values. If you apply
176 one of them to an array or a hash, it will convert the array or hash to
177 a scalar value (the length of an array, or the population info of a
178 hash) and then work on that scalar value. This is probably not what
179 you meant to do. See L<perlfunc/grep> and L<perlfunc/map> for
182 =item Arg too short for msgsnd
184 (F) msgsnd() requires a string at least as long as sizeof(long).
186 =item Argument "%s" isn't numeric%s
188 (W numeric) The indicated string was fed as an argument to an operator
189 that expected a numeric value instead. If you're fortunate the message
190 will identify which operator was so unfortunate.
192 Note that for the C<Inf> and C<NaN> (infinity and not-a-number) the
193 definition of "numeric" is somewhat unusual: the strings themselves
194 (like "Inf") are considered numeric, and anything following them is
195 considered non-numeric.
197 =item Argument list not closed for PerlIO layer "%s"
199 (W layer) When pushing a layer with arguments onto the Perl I/O
200 system you forgot the ) that closes the argument list. (Layers
201 take care of transforming data between external and internal
202 representations.) Perl stopped parsing the layer list at this
203 point and did not attempt to push this layer. If your program
204 didn't explicitly request the failing operation, it may be the
205 result of the value of the environment variable PERLIO.
207 =item Argument "%s" treated as 0 in increment (++)
209 (W numeric) The indicated string was fed as an argument to the C<++>
210 operator which expects either a number or a string matching
211 C</^[a-zA-Z]*[0-9]*\z/>. See L<perlop/Auto-increment and
212 Auto-decrement> for details.
214 =item assertion botched: %s
216 (X) The malloc package that comes with Perl had an internal failure.
218 =item Assertion %s failed: file "%s", line %d
220 (X) A general assertion failed. The file in question must be examined.
222 =item Assigned value is not a reference
224 (F) You tried to assign something that was not a reference to an lvalue
225 reference (e.g., C<\$x = $y>). If you meant to make $x an alias to $y, use
228 =item Assigned value is not %s reference
230 (F) You tried to assign a reference to a reference constructor, but the
231 two references were not of the same type. You cannot alias a scalar to
232 an array, or an array to a hash; the two types must match.
237 \$x = $y; # error; did you mean \$y?
239 =item Assigning non-zero to $[ is no longer possible
241 (F) When the "array_base" feature is disabled (e.g., under C<use v5.16;>)
242 the special variable C<$[>, which is deprecated, is now a fixed zero value.
244 =item Assignment to both a list and a scalar
246 (F) If you assign to a conditional operator, the 2nd and 3rd arguments
247 must either both be scalars or both be lists. Otherwise Perl won't
248 know which context to supply to the right side.
250 =item <> at require-statement should be quotes
252 (F) You wrote C<< require <file> >> when you should have written
255 =item Attempt to access disallowed key '%s' in a restricted hash
257 (F) The failing code has attempted to get or set a key which is not in
258 the current set of allowed keys of a restricted hash.
260 =item Attempt to bless into a freed package
262 (F) You wrote C<bless $foo> with one argument after somehow causing
263 the current package to be freed. Perl cannot figure out what to
264 do, so it throws up in hands in despair.
266 =item Attempt to bless into a reference
268 (F) The CLASSNAME argument to the bless() operator is expected to be
269 the name of the package to bless the resulting object into. You've
270 supplied instead a reference to something: perhaps you wrote
276 bless $self, ref($proto) || $proto;
278 If you actually want to bless into the stringified version
279 of the reference supplied, you need to stringify it yourself, for
282 bless $self, "$proto";
284 =item Attempt to clear deleted array
286 (S debugging) An array was assigned to when it was being freed.
287 Freed values are not supposed to be visible to Perl code. This
288 can also happen if XS code calls C<av_clear> from a custom magic
289 callback on the array.
291 =item Attempt to delete disallowed key '%s' from a restricted hash
293 (F) The failing code attempted to delete from a restricted hash a key
294 which is not in its key set.
296 =item Attempt to delete readonly key '%s' from a restricted hash
298 (F) The failing code attempted to delete a key whose value has been
299 declared readonly from a restricted hash.
301 =item Attempt to free non-arena SV: 0x%x
303 (S internal) All SV objects are supposed to be allocated from arenas
304 that will be garbage collected on exit. An SV was discovered to be
305 outside any of those arenas.
307 =item Attempt to free nonexistent shared string '%s'%s
309 (S internal) Perl maintains a reference-counted internal table of
310 strings to optimize the storage and access of hash keys and other
311 strings. This indicates someone tried to decrement the reference count
312 of a string that can no longer be found in the table.
314 =item Attempt to free temp prematurely: SV 0x%x
316 (S debugging) Mortalized values are supposed to be freed by the
317 free_tmps() routine. This indicates that something else is freeing the
318 SV before the free_tmps() routine gets a chance, which means that the
319 free_tmps() routine will be freeing an unreferenced scalar when it does
322 =item Attempt to free unreferenced glob pointers
324 (S internal) The reference counts got screwed up on symbol aliases.
326 =item Attempt to free unreferenced scalar: SV 0x%x
328 (S internal) Perl went to decrement the reference count of a scalar to
329 see if it would go to 0, and discovered that it had already gone to 0
330 earlier, and should have been freed, and in fact, probably was freed.
331 This could indicate that SvREFCNT_dec() was called too many times, or
332 that SvREFCNT_inc() was called too few times, or that the SV was
333 mortalized when it shouldn't have been, or that memory has been
336 =item Attempt to pack pointer to temporary value
338 (W pack) You tried to pass a temporary value (like the result of a
339 function, or a computed expression) to the "p" pack() template. This
340 means the result contains a pointer to a location that could become
341 invalid anytime, even before the end of the current statement. Use
342 literals or global values as arguments to the "p" pack() template to
345 =item Attempt to reload %s aborted.
347 (F) You tried to load a file with C<use> or C<require> that failed to
348 compile once already. Perl will not try to compile this file again
349 unless you delete its entry from %INC. See L<perlfunc/require> and
352 =item Attempt to set length of freed array
354 (W misc) You tried to set the length of an array which has
355 been freed. You can do this by storing a reference to the
356 scalar representing the last index of an array and later
357 assigning through that reference. For example
359 $r = do {my @a; \$#a};
362 =item Attempt to use reference as lvalue in substr
364 (W substr) You supplied a reference as the first argument to substr()
365 used as an lvalue, which is pretty strange. Perhaps you forgot to
366 dereference it first. See L<perlfunc/substr>.
368 =item Attribute "locked" is deprecated
370 (D deprecated) You have used the attributes pragma to modify the
371 "locked" attribute on a code reference. The :locked attribute is
372 obsolete, has had no effect since 5005 threads were removed, and
373 will be removed in a future release of Perl 5.
375 =item Attribute prototype(%s) discards earlier prototype attribute in same sub
377 (W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
378 example. Since each sub can only have one prototype, the earlier
379 declaration(s) are discarded while the last one is applied.
381 =item Attribute "unique" is deprecated
383 (D deprecated) You have used the attributes pragma to modify
384 the "unique" attribute on an array, hash or scalar reference.
385 The :unique attribute has had no effect since Perl 5.8.8, and
386 will be removed in a future release of Perl 5.
388 =item av_reify called on tied array
390 (S debugging) This indicates that something went wrong and Perl got I<very>
391 confused about C<@_> or C<@DB::args> being tied.
393 =item Bad arg length for %s, is %u, should be %d
395 (F) You passed a buffer of the wrong size to one of msgctl(), semctl()
396 or shmctl(). In C parlance, the correct sizes are, respectively,
397 S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
398 S<sizeof(struct shmid_ds *)>.
400 =item Bad evalled substitution pattern
402 (F) You've used the C</e> switch to evaluate the replacement for a
403 substitution, but perl found a syntax error in the code to evaluate,
404 most likely an unexpected right brace '}'.
406 =item Bad filehandle: %s
408 (F) A symbol was passed to something wanting a filehandle, but the
409 symbol has no filehandle associated with it. Perhaps you didn't do an
410 open(), or did it in another package.
412 =item Bad free() ignored
414 (S malloc) An internal routine called free() on something that had never
415 been malloc()ed in the first place. Mandatory, but can be disabled by
416 setting environment variable C<PERL_BADFREE> to 0.
418 This message can be seen quite often with DB_File on systems with "hard"
419 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
420 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
424 (P) One of the internal hash routines was passed a null HV pointer.
426 =item Badly placed ()'s
428 (A) You've accidentally run your script through B<csh> instead
429 of Perl. Check the #! line, or manually feed your script into
432 =item Bad name after %s
434 (F) You started to name a symbol by using a package prefix, and then
435 didn't finish the symbol. In particular, you can't interpolate outside
444 $sym = "mypack::$var";
446 =item Bad plugin affecting keyword '%s'
448 (F) An extension using the keyword plugin mechanism violated the
451 =item Bad realloc() ignored
453 (S malloc) An internal routine called realloc() on something that
454 had never been malloc()ed in the first place. Mandatory, but can
455 be disabled by setting the environment variable C<PERL_BADFREE> to 1.
457 =item Bad symbol for array
459 (P) An internal request asked to add an array entry to something that
460 wasn't a symbol table entry.
462 =item Bad symbol for dirhandle
464 (P) An internal request asked to add a dirhandle entry to something
465 that wasn't a symbol table entry.
467 =item Bad symbol for filehandle
469 (P) An internal request asked to add a filehandle entry to something
470 that wasn't a symbol table entry.
472 =item Bad symbol for hash
474 (P) An internal request asked to add a hash entry to something that
475 wasn't a symbol table entry.
477 =item Bad symbol for scalar
479 (P) An internal request asked to add a scalar entry to something that
480 wasn't a symbol table entry.
482 =item Bareword found in conditional
484 (W bareword) The compiler found a bareword where it expected a
485 conditional, which often indicates that an || or && was parsed as part
486 of the last argument of the previous construct, for example:
490 It may also indicate a misspelled constant that has been interpreted as
493 use constant TYPO => 1;
494 if (TYOP) { print "foo" }
496 The C<strict> pragma is useful in avoiding such errors.
498 =item Bareword "%s" not allowed while "strict subs" in use
500 (F) With "strict subs" in use, a bareword is only allowed as a
501 subroutine identifier, in curly brackets or to the left of the "=>"
502 symbol. Perhaps you need to predeclare a subroutine?
504 =item Bareword "%s" refers to nonexistent package
506 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
507 compiler saw no other uses of that namespace before that point. Perhaps
508 you need to predeclare a package?
510 =item BEGIN failed--compilation aborted
512 (F) An untrapped exception was raised while executing a BEGIN
513 subroutine. Compilation stops immediately and the interpreter is
516 =item BEGIN not safe after errors--compilation aborted
518 (F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
519 implies a C<BEGIN {}>) after one or more compilation errors had already
520 occurred. Since the intended environment for the C<BEGIN {}> could not
521 be guaranteed (due to the errors), and since subsequent code likely
522 depends on its correct operation, Perl just gave up.
524 =item \%d better written as $%d
526 (W syntax) Outside of patterns, backreferences live on as variables.
527 The use of backslashes is grandfathered on the right-hand side of a
528 substitution, but stylistically it's better to use the variable form
529 because other Perl programmers will expect it, and it works better if
530 there are more than 9 backreferences.
532 =item Binary number > 0b11111111111111111111111111111111 non-portable
534 (W portable) The binary number you specified is larger than 2**32-1
535 (4294967295) and therefore non-portable between systems. See
536 L<perlport> for more on portability concerns.
538 =item bind() on closed socket %s
540 (W closed) You tried to do a bind on a closed socket. Did you forget to
541 check the return value of your socket() call? See L<perlfunc/bind>.
543 =item binmode() on closed filehandle %s
545 (W unopened) You tried binmode() on a filehandle that was never opened.
546 Check your control flow and number of arguments.
548 =item Bit vector size > 32 non-portable
550 (W portable) Using bit vector sizes larger than 32 is non-portable.
552 =item Bizarre copy of %s
554 (P) Perl detected an attempt to copy an internal value that is not
557 =item Bizarre SvTYPE [%d]
559 (P) When starting a new thread or returning values from a thread, Perl
560 encountered an invalid data type.
562 =item Both or neither range ends should be Unicode in regex; marked by
565 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
567 In a bracketed character class in a regular expression pattern, you
568 had a range which has exactly one end of it specified using C<\N{}>, and
569 the other end is specified using a non-portable mechanism. Perl treats
570 the range as a Unicode range, that is, all the characters in it are
571 considered to be the Unicode characters, and which may be different code
572 points on some platforms Perl runs on. For example, C<[\N{U+06}-\x08]>
573 is treated as if you had instead said C<[\N{U+06}-\N{U+08}]>, that is it
574 matches the characters whose code points in Unicode are 6, 7, and 8.
575 But that C<\x08> might indicate that you meant something different, so
576 the warning gets raised.
578 =item Buffer overflow in prime_env_iter: %s
580 (W internal) A warning peculiar to VMS. While Perl was preparing to
581 iterate over %ENV, it encountered a logical name or symbol definition
582 which was too long, so it was truncated to the string shown.
584 =item Callback called exit
586 (F) A subroutine invoked from an external package via call_sv()
587 exited by calling exit.
589 =item %s() called too early to check prototype
591 (W prototype) You've called a function that has a prototype before the
592 parser saw a definition or declaration for it, and Perl could not check
593 that the call conforms to the prototype. You need to either add an
594 early prototype declaration for the subroutine in question, or move the
595 subroutine definition ahead of the call to get proper prototype
596 checking. Alternatively, if you are certain that you're calling the
597 function correctly, you may put an ampersand before the name to avoid
598 the warning. See L<perlsub>.
600 =item Calling POSIX::%s() is deprecated
602 (D deprecated) You called a function whose use is deprecated. See
603 the function's name in L<POSIX> for details.
607 (F) You passed an invalid number (like an infinity or not-a-number) to C<chr>.
609 =item Cannot compress %f in pack
611 (F) You tried compressing an infinity or not-a-number as an unsigned
612 integer with BER, which makes no sense.
614 =item Cannot compress integer in pack
616 (F) An argument to pack("w",...) was too large to compress.
617 The BER compressed integer format can only be used with positive
618 integers, and you attempted to compress a very large number (> 1e308).
619 See L<perlfunc/pack>.
621 =item Cannot compress negative numbers in pack
623 (F) An argument to pack("w",...) was negative. The BER compressed integer
624 format can only be used with positive integers. See L<perlfunc/pack>.
626 =item Cannot convert a reference to %s to typeglob
628 (F) You manipulated Perl's symbol table directly, stored a reference
629 in it, then tried to access that symbol via conventional Perl syntax.
630 The access triggers Perl to autovivify that typeglob, but it there is
631 no legal conversion from that type of reference to a typeglob.
633 =item Cannot copy to %s
635 (P) Perl detected an attempt to copy a value to an internal type that cannot
636 be directly assigned to.
638 =item Cannot find encoding "%s"
640 (S io) You tried to apply an encoding that did not exist to a filehandle,
641 either with open() or binmode().
643 =item Cannot pack %f with '%c'
645 (F) You tried converting an infinity or not-a-number to an integer,
646 which makes no sense.
648 =item Cannot printf %f with '%c'
650 (F) You tried printing an infinity or not-a-number as a character (%c),
651 which makes no sense. Maybe you meant '%s', or just stringifying it?
653 =item Cannot set tied @DB::args
655 (F) C<caller> tried to set C<@DB::args>, but found it tied. Tying C<@DB::args>
656 is not supported. (Before this error was added, it used to crash.)
658 =item Cannot tie unreifiable array
660 (P) You somehow managed to call C<tie> on an array that does not
661 keep a reference count on its arguments and cannot be made to
662 do so. Such arrays are not even supposed to be accessible to
663 Perl code, but are only used internally.
665 =item Cannot yet reorder sv_catpvfn() arguments from va_list
667 (F) Some XS code tried to use C<sv_catpvfn()> or a related function with a
668 format string that specifies explicit indexes for some of the elements, and
669 using a C-style variable-argument list (a C<va_list>). This is not currently
670 supported. XS authors wanting to do this must instead construct a C array of
671 C<SV*> scalars containing the arguments.
673 =item Can only compress unsigned integers in pack
675 (F) An argument to pack("w",...) was not an integer. The BER compressed
676 integer format can only be used with positive integers, and you attempted
677 to compress something else. See L<perlfunc/pack>.
679 =item Can't bless non-reference value
681 (F) Only hard references may be blessed. This is how Perl "enforces"
682 encapsulation of objects. See L<perlobj>.
684 =item Can't "break" in a loop topicalizer
686 (F) You called C<break>, but you're in a C<foreach> block rather than
687 a C<given> block. You probably meant to use C<next> or C<last>.
689 =item Can't "break" outside a given block
691 (F) You called C<break>, but you're not inside a C<given> block.
693 =item Can't call method "%s" on an undefined value
695 (F) You used the syntax of a method call, but the slot filled by the
696 object reference or package name contains an undefined value. Something
697 like this will reproduce the error:
700 process $BADREF 1,2,3;
701 $BADREF->process(1,2,3);
703 =item Can't call method "%s" on unblessed reference
705 (F) A method call must know in what package it's supposed to run. It
706 ordinarily finds this out from the object reference you supply, but you
707 didn't supply an object reference in this case. A reference isn't an
708 object reference until it has been blessed. See L<perlobj>.
710 =item Can't call method "%s" without a package or object reference
712 (F) You used the syntax of a method call, but the slot filled by the
713 object reference or package name contains an expression that returns a
714 defined value which is neither an object reference nor a package name.
715 Something like this will reproduce the error:
718 process $BADREF 1,2,3;
719 $BADREF->process(1,2,3);
721 =item Can't call mro_isa_changed_in() on anonymous symbol table
723 (P) Perl got confused as to whether a hash was a plain hash or a
724 symbol table hash when trying to update @ISA caches.
726 =item Can't call mro_method_changed_in() on anonymous symbol table
728 (F) An XS module tried to call C<mro_method_changed_in> on a hash that was
729 not attached to the symbol table.
731 =item Can't chdir to %s
733 (F) You called C<perl -x/foo/bar>, but F</foo/bar> is not a directory
734 that you can chdir to, possibly because it doesn't exist.
736 =item Can't check filesystem of script "%s" for nosuid
738 (P) For some reason you can't check the filesystem of the script for
741 =item Can't coerce %s to %s in %s
743 (F) Certain types of SVs, in particular real symbol table entries
744 (typeglobs), can't be forced to stop being what they are. So you can't
754 but then $foo no longer contains a glob.
756 =item Can't "continue" outside a when block
758 (F) You called C<continue>, but you're not inside a C<when>
761 =item Can't create pipe mailbox
763 (P) An error peculiar to VMS. The process is suffering from exhausted
764 quotas or other plumbing problems.
766 =item Can't declare %s in "%s"
768 (F) Only scalar, array, and hash variables may be declared as "my", "our" or
769 "state" variables. They must have ordinary identifiers as names.
771 =item Can't "default" outside a topicalizer
773 (F) You have used a C<default> block that is neither inside a
774 C<foreach> loop nor a C<given> block. (Note that this error is
775 issued on exit from the C<default> block, so you won't get the
776 error if you use an explicit C<continue>.)
778 =item Can't do inplace edit: %s is not a regular file
780 (S inplace) You tried to use the B<-i> switch on a special file, such as
781 a file in /dev, a FIFO or an uneditable directory. The file was ignored.
783 =item Can't do inplace edit on %s: %s
785 (S inplace) The creation of the new file failed for the indicated
788 =item Can't do inplace edit without backup
790 (F) You're on a system such as MS-DOS that gets confused if you try
791 reading from a deleted (but still opened) file. You have to say
792 C<-i.bak>, or some such.
794 =item Can't do inplace edit: %s would not be unique
796 (S inplace) Your filesystem does not support filenames longer than 14
797 characters and Perl was unable to create a unique filename during
798 inplace editing with the B<-i> switch. The file was ignored.
800 =item Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".
802 (W locale) You are 1) running under "C<use locale>"; 2) the current
803 locale is not a UTF-8 one; 3) you tried to do the designated case-change
804 operation on the specified Unicode character; and 4) the result of this
805 operation would mix Unicode and locale rules, which likely conflict.
806 Mixing of different rule types is forbidden, so the operation was not
807 done; instead the result is the indicated value, which is the best
808 available that uses entirely Unicode rules. That turns out to almost
809 always be the original character, unchanged.
811 It is generally a bad idea to mix non-UTF-8 locales and Unicode, and
812 this issue is one of the reasons why. This warning is raised when
813 Unicode rules would normally cause the result of this operation to
814 contain a character that is in the range specified by the locale,
815 0..255, and hence is subject to the locale's rules, not Unicode's.
817 If you are using locale purely for its characteristics related to things
818 like its numeric and time formatting (and not C<LC_CTYPE>), consider
819 using a restricted form of the locale pragma (see L<perllocale/The "use
820 locale" pragma>) like "S<C<use locale ':not_characters'>>".
822 Note that failed case-changing operations done as a result of
823 case-insensitive C</i> regular expression matching will show up in this
824 warning as having the C<fc> operation (as that is what the regular
825 expression engine calls behind the scenes.)
827 =item Can't do waitpid with flags
829 (F) This machine doesn't have either waitpid() or wait4(), so only
830 waitpid() without flags is emulated.
832 =item Can't emulate -%s on #! line
834 (F) The #! line specifies a switch that doesn't make sense at this
835 point. For example, it'd be kind of silly to put a B<-x> on the #!
838 =item Can't %s %s-endian %ss on this platform
840 (F) Your platform's byte-order is neither big-endian nor little-endian,
841 or it has a very strange pointer size. Packing and unpacking big- or
842 little-endian floating point values and pointers may not be possible.
843 See L<perlfunc/pack>.
845 =item Can't exec "%s": %s
847 (W exec) A system(), exec(), or piped open call could not execute the
848 named program for the indicated reason. Typical reasons include: the
849 permissions were wrong on the file, the file wasn't found in
850 C<$ENV{PATH}>, the executable in question was compiled for another
851 architecture, or the #! line in a script points to an interpreter that
852 can't be run for similar reasons. (Or maybe your system doesn't support
857 (F) Perl was trying to execute the indicated program for you because
858 that's what the #! line said. If that's not what you wanted, you may
859 need to mention "perl" on the #! line somewhere.
861 =item Can't execute %s
863 (F) You used the B<-S> switch, but the copies of the script to execute
864 found in the PATH did not have correct permissions.
866 =item Can't find an opnumber for "%s"
868 (F) A string of a form C<CORE::word> was given to prototype(), but there
869 is no builtin with the name C<word>.
871 =item Can't find %s character property "%s"
873 (F) You used C<\p{}> or C<\P{}> but the character property by that name
874 could not be found. Maybe you misspelled the name of the property?
875 See L<perluniprops/Properties accessible through \p{} and \P{}>
876 for a complete list of available official properties.
878 =item Can't find label %s
880 (F) You said to goto a label that isn't mentioned anywhere that it's
881 possible for us to go to. See L<perlfunc/goto>.
883 =item Can't find %s on PATH
885 (F) You used the B<-S> switch, but the script to execute could not be
888 =item Can't find %s on PATH, '.' not in PATH
890 (F) You used the B<-S> switch, but the script to execute could not be
891 found in the PATH, or at least not with the correct permissions. The
892 script exists in the current directory, but PATH prohibits running it.
894 =item Can't find string terminator %s anywhere before EOF
896 (F) Perl strings can stretch over multiple lines. This message means
897 that the closing delimiter was omitted. Because bracketed quotes count
898 nesting levels, the following is missing its final parenthesis:
900 print q(The character '(' starts a side comment.);
902 If you're getting this error from a here-document, you may have
903 included unseen whitespace before or after your closing tag or there
904 may not be a linebreak after it. A good programmer's editor will have
905 a way to help you find these characters (or lack of characters). See
906 L<perlop> for the full details on here-documents.
908 =item Can't find Unicode property definition "%s"
910 (F) You may have tried to use C<\p> which means a Unicode
911 property (for example C<\p{Lu}> matches all uppercase
912 letters). If you did mean to use a Unicode property, see
913 L<perluniprops/Properties accessible through \p{} and \P{}>
914 for a complete list of available properties. If you didn't
915 mean to use a Unicode property, escape the C<\p>, either by
916 C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, or
921 (F) A fatal error occurred while trying to fork while opening a
924 =item Can't fork, trying again in 5 seconds
926 (W pipe) A fork in a piped open failed with EAGAIN and will be retried
929 =item Can't get filespec - stale stat buffer?
931 (S) A warning peculiar to VMS. This arises because of the difference
932 between access checks under VMS and under the Unix model Perl assumes.
933 Under VMS, access checks are done by filename, rather than by bits in
934 the stat buffer, so that ACLs and other protections can be taken into
935 account. Unfortunately, Perl assumes that the stat buffer contains all
936 the necessary information, and passes it, instead of the filespec, to
937 the access-checking routine. It will try to retrieve the filespec using
938 the device name and FID present in the stat buffer, but this works only
939 if you haven't made a subsequent call to the CRTL stat() routine,
940 because the device name is overwritten with each call. If this warning
941 appears, the name lookup failed, and the access-checking routine gave up
942 and returned FALSE, just to be conservative. (Note: The access-checking
943 routine knows about the Perl C<stat> operator and file tests, so you
944 shouldn't ever see this warning in response to a Perl command; it arises
945 only if some internal code takes stat buffers lightly.)
947 =item Can't get pipe mailbox device name
949 (P) An error peculiar to VMS. After creating a mailbox to act as a
950 pipe, Perl can't retrieve its name for later use.
952 =item Can't get SYSGEN parameter value for MAXBUF
954 (P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
955 mailbox buffers to be, and didn't get an answer.
957 =item Can't "goto" into the middle of a foreach loop
959 (F) A "goto" statement was executed to jump into the middle of a foreach
960 loop. You can't get there from here. See L<perlfunc/goto>.
962 =item Can't "goto" out of a pseudo block
964 (F) A "goto" statement was executed to jump out of what might look like
965 a block, except that it isn't a proper block. This usually occurs if
966 you tried to jump out of a sort() block or subroutine, which is a no-no.
967 See L<perlfunc/goto>.
969 =item Can't goto subroutine from an eval-%s
971 (F) The "goto subroutine" call can't be used to jump out of an eval
974 =item Can't goto subroutine from a sort sub (or similar callback)
976 (F) The "goto subroutine" call can't be used to jump out of the
977 comparison sub for a sort(), or from a similar callback (such
978 as the reduce() function in List::Util).
980 =item Can't goto subroutine outside a subroutine
982 (F) The deeply magical "goto subroutine" call can only replace one
983 subroutine call for another. It can't manufacture one out of whole
984 cloth. In general you should be calling it out of only an AUTOLOAD
985 routine anyway. See L<perlfunc/goto>.
987 =item Can't ignore signal CHLD, forcing to default
989 (W signal) Perl has detected that it is being run with the SIGCHLD
990 signal (sometimes known as SIGCLD) disabled. Since disabling this
991 signal will interfere with proper determination of exit status of child
992 processes, Perl has reset the signal to its default value. This
993 situation typically indicates that the parent program under which Perl
994 may be running (e.g. cron) is being very careless.
996 =item Can't kill a non-numeric process ID
998 (F) Process identifiers must be (signed) integers. It is a fatal error to
999 attempt to kill() an undefined, empty-string or otherwise non-numeric
1002 =item Can't "last" outside a loop block
1004 (F) A "last" statement was executed to break out of the current block,
1005 except that there's this itty bitty problem called there isn't a current
1006 block. Note that an "if" or "else" block doesn't count as a "loopish"
1007 block, as doesn't a block given to sort(), map() or grep(). You can
1008 usually double the curlies to get the same effect though, because the
1009 inner curlies will be considered a block that loops once. See
1012 =item Can't linearize anonymous symbol table
1014 (F) Perl tried to calculate the method resolution order (MRO) of a
1015 package, but failed because the package stash has no name.
1017 =item Can't load '%s' for module %s
1019 (F) The module you tried to load failed to load a dynamic extension.
1020 This may either mean that you upgraded your version of perl to one
1021 that is incompatible with your old dynamic extensions (which is known
1022 to happen between major versions of perl), or (more likely) that your
1023 dynamic extension was built against an older version of the library
1024 that is installed on your system. You may need to rebuild your old
1027 =item Can't localize lexical variable %s
1029 (F) You used local on a variable name that was previously declared as a
1030 lexical variable using "my" or "state". This is not allowed. If you
1031 want to localize a package variable of the same name, qualify it with
1034 =item Can't localize through a reference
1036 (F) You said something like C<local $$ref>, which Perl can't currently
1037 handle, because when it goes to restore the old value of whatever $ref
1038 pointed to after the scope of the local() is finished, it can't be sure
1039 that $ref will still be a reference.
1041 =item Can't locate %s
1043 (F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be found.
1044 Perl looks for the file in all the locations mentioned in @INC, unless
1045 the file name included the full path to the file. Perhaps you need
1046 to set the PERL5LIB or PERL5OPT environment variable to say where the
1047 extra library is, or maybe the script needs to add the library name
1048 to @INC. Or maybe you just misspelled the name of the file. See
1049 L<perlfunc/require> and L<lib>.
1051 =item Can't locate auto/%s.al in @INC
1053 (F) A function (or method) was called in a package which allows
1054 autoload, but there is no function to autoload. Most probable causes
1055 are a misprint in a function/method name or a failure to C<AutoSplit>
1056 the file, say, by doing C<make install>.
1058 =item Can't locate loadable object for module %s in @INC
1060 (F) The module you loaded is trying to load an external library, like
1061 for example, F<foo.so> or F<bar.dll>, but the L<DynaLoader> module was
1062 unable to locate this library. See L<DynaLoader>.
1064 =item Can't locate object method "%s" via package "%s"
1066 (F) You called a method correctly, and it correctly indicated a package
1067 functioning as a class, but that package doesn't define that particular
1068 method, nor does any of its base classes. See L<perlobj>.
1070 =item Can't locate object method "%s" via package "%s" (perhaps you forgot
1073 (F) You called a method on a class that did not exist, and the method
1074 could not be found in UNIVERSAL. This often means that a method
1075 requires a package that has not been loaded.
1077 =item Can't locate package %s for @%s::ISA
1079 (W syntax) The @ISA array contained the name of another package that
1080 doesn't seem to exist.
1082 =item Can't locate PerlIO%s
1084 (F) You tried to use in open() a PerlIO layer that does not exist,
1085 e.g. open(FH, ">:nosuchlayer", "somefile").
1087 =item Can't make list assignment to %ENV on this system
1089 (F) List assignment to %ENV is not supported on some systems, notably
1092 =item Can't make loaded symbols global on this platform while loading %s
1094 (S) A module passed the flag 0x01 to DynaLoader::dl_load_file() to request
1095 that symbols from the stated file are made available globally within the
1096 process, but that functionality is not available on this platform. Whilst
1097 the module likely will still work, this may prevent the perl interpreter
1098 from loading other XS-based extensions which need to link directly to
1099 functions defined in the C or XS code in the stated file.
1101 =item Can't modify %s in %s
1103 (F) You aren't allowed to assign to the item indicated, or otherwise try
1104 to change it, such as with an auto-increment.
1106 =item Can't modify nonexistent substring
1108 (P) The internal routine that does assignment to a substr() was handed
1111 =item Can't modify non-lvalue subroutine call
1113 (F) Subroutines meant to be used in lvalue context should be declared as
1114 such. See L<perlsub/"Lvalue subroutines">.
1116 =item Can't modify reference to %s in %s assignment
1118 (F) Only a limited number of constructs can be used as the argument to a
1119 reference constructor on the left-hand side of an assignment, and what
1120 you used was not one of them. See L<perlref/Assigning to References>.
1122 =item Can't modify reference to localized parenthesized array in list
1125 (F) Assigning to C<\local(@array)> or C<\(local @array)> is not supported, as
1126 it is not clear exactly what it should do. If you meant to make @array
1127 refer to some other array, use C<\@array = \@other_array>. If you want to
1128 make the elements of @array aliases of the scalars referenced on the
1129 right-hand side, use C<\(@array) = @scalar_refs>.
1131 =item Can't modify reference to parenthesized hash in list assignment
1133 (F) Assigning to C<\(%hash)> is not supported. If you meant to make %hash
1134 refer to some other hash, use C<\%hash = \%other_hash>. If you want to
1135 make the elements of %hash into aliases of the scalars referenced on the
1136 right-hand side, use a hash slice: C<\@hash{@keys} = @those_scalar_refs>.
1138 =item Can't msgrcv to read-only var
1140 (F) The target of a msgrcv must be modifiable to be used as a receive
1143 =item Can't "next" outside a loop block
1145 (F) A "next" statement was executed to reiterate the current block, but
1146 there isn't a current block. Note that an "if" or "else" block doesn't
1147 count as a "loopish" block, as doesn't a block given to sort(), map() or
1148 grep(). You can usually double the curlies to get the same effect
1149 though, because the inner curlies will be considered a block that loops
1150 once. See L<perlfunc/next>.
1152 =item Can't open %s: %s
1154 (S inplace) The implicit opening of a file through use of the C<< <> >>
1155 filehandle, either implicitly under the C<-n> or C<-p> command-line
1156 switches, or explicitly, failed for the indicated reason. Usually
1157 this is because you don't have read permission for a file which
1158 you named on the command line.
1160 (F) You tried to call perl with the B<-e> switch, but F</dev/null> (or
1161 your operating system's equivalent) could not be opened.
1163 =item Can't open a reference
1165 (W io) You tried to open a scalar reference for reading or writing,
1166 using the 3-arg open() syntax:
1170 but your version of perl is compiled without perlio, and this form of
1171 open is not supported.
1173 =item Can't open bidirectional pipe
1175 (W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
1176 You can try any of several modules in the Perl library to do this, such
1177 as IPC::Open2. Alternately, direct the pipe's output to a file using
1178 ">", and then read it in under a different file handle.
1180 =item Can't open error file %s as stderr
1182 (F) An error peculiar to VMS. Perl does its own command line
1183 redirection, and couldn't open the file specified after '2>' or '2>>' on
1184 the command line for writing.
1186 =item Can't open input file %s as stdin
1188 (F) An error peculiar to VMS. Perl does its own command line
1189 redirection, and couldn't open the file specified after '<' on the
1190 command line for reading.
1192 =item Can't open output file %s as stdout
1194 (F) An error peculiar to VMS. Perl does its own command line
1195 redirection, and couldn't open the file specified after '>' or '>>' on
1196 the command line for writing.
1198 =item Can't open output pipe (name: %s)
1200 (P) An error peculiar to VMS. Perl does its own command line
1201 redirection, and couldn't open the pipe into which to send data destined
1204 =item Can't open perl script "%s": %s
1206 (F) The script you specified can't be opened for the indicated reason.
1208 If you're debugging a script that uses #!, and normally relies on the
1209 shell's $PATH search, the -S option causes perl to do that search, so
1210 you don't have to type the path or C<`which $scriptname`>.
1212 =item Can't read CRTL environ
1214 (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
1215 from the CRTL's internal environment array and discovered the array was
1216 missing. You need to figure out where your CRTL misplaced its environ
1217 or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
1220 =item Can't redeclare "%s" in "%s"
1222 (F) A "my", "our" or "state" declaration was found within another declaration,
1223 such as C<my ($x, my($y), $z)> or C<our (my $x)>.
1225 =item Can't "redo" outside a loop block
1227 (F) A "redo" statement was executed to restart the current block, but
1228 there isn't a current block. Note that an "if" or "else" block doesn't
1229 count as a "loopish" block, as doesn't a block given to sort(), map()
1230 or grep(). You can usually double the curlies to get the same effect
1231 though, because the inner curlies will be considered a block that
1232 loops once. See L<perlfunc/redo>.
1234 =item Can't remove %s: %s, skipping file
1236 (S inplace) You requested an inplace edit without creating a backup
1237 file. Perl was unable to remove the original file to replace it with
1238 the modified file. The file was left unmodified.
1240 =item Can't rename %s to %s: %s, skipping file
1242 (S inplace) The rename done by the B<-i> switch failed for some reason,
1243 probably because you don't have write permission to the directory.
1245 =item Can't reopen input pipe (name: %s) in binary mode
1247 (P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
1248 to reopen it to accept binary data. Alas, it failed.
1250 =item Can't represent character for Ox%X on this platform
1252 (F) There is a hard limit to how big a character code point can be due
1253 to the fundamental properties of UTF-8, especially on EBCDIC
1254 platforms. The given code point exceeds that. The only work-around is
1255 to not use such a large code point.
1257 =item Can't reset %ENV on this system
1259 (F) You called C<reset('E')> or similar, which tried to reset
1260 all variables in the current package beginning with "E". In
1261 the main package, that includes %ENV. Resetting %ENV is not
1262 supported on some systems, notably VMS.
1264 =item Can't resolve method "%s" overloading "%s" in package "%s"
1266 (F)(P) Error resolving overloading specified by a method name (as
1267 opposed to a subroutine reference): no such method callable via the
1268 package. If the method name is C<???>, this is an internal error.
1270 =item Can't return %s from lvalue subroutine
1272 (F) Perl detected an attempt to return illegal lvalues (such as
1273 temporary or readonly values) from a subroutine used as an lvalue. This
1276 =item Can't return outside a subroutine
1278 (F) The return statement was executed in mainline code, that is, where
1279 there was no subroutine call to return out of. See L<perlsub>.
1281 =item Can't return %s to lvalue scalar context
1283 (F) You tried to return a complete array or hash from an lvalue
1284 subroutine, but you called the subroutine in a way that made Perl
1285 think you meant to return only one value. You probably meant to
1286 write parentheses around the call to the subroutine, which tell
1287 Perl that the call should be in list context.
1289 =item Can't stat script "%s"
1291 (P) For some reason you can't fstat() the script even though you have it
1292 open already. Bizarre.
1294 =item Can't take log of %g
1296 (F) For ordinary real numbers, you can't take the logarithm of a
1297 negative number or zero. There's a Math::Complex package that comes
1298 standard with Perl, though, if you really want to do that for the
1301 =item Can't take sqrt of %g
1303 (F) For ordinary real numbers, you can't take the square root of a
1304 negative number. There's a Math::Complex package that comes standard
1305 with Perl, though, if you really want to do that.
1307 =item Can't undef active subroutine
1309 (F) You can't undefine a routine that's currently running. You can,
1310 however, redefine it while it's running, and you can even undef the
1311 redefined subroutine while the old routine is running. Go figure.
1313 =item Can't upgrade %s (%d) to %d
1315 (P) The internal sv_upgrade routine adds "members" to an SV, making it
1316 into a more specialized kind of SV. The top several SV types are so
1317 specialized, however, that they cannot be interconverted. This message
1318 indicates that such a conversion was attempted.
1320 =item Can't use '%c' after -mname
1322 (F) You tried to call perl with the B<-m> switch, but you put something
1323 other than "=" after the module name.
1325 =item Can't use a hash as a reference
1327 (F) You tried to use a hash as a reference, as in
1328 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl
1329 <= 5.22.0 used to allow this syntax, but shouldn't
1330 have. This was deprecated in perl 5.6.1.
1332 =item Can't use an array as a reference
1334 (F) You tried to use an array as a reference, as in
1335 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.22.0
1336 used to allow this syntax, but shouldn't have. This
1337 was deprecated in perl 5.6.1.
1339 =item Can't use anonymous symbol table for method lookup
1341 (F) The internal routine that does method lookup was handed a symbol
1342 table that doesn't have a name. Symbol tables can become anonymous
1343 for example by undefining stashes: C<undef %Some::Package::>.
1345 =item Can't use an undefined value as %s reference
1347 (F) A value used as either a hard reference or a symbolic reference must
1348 be a defined value. This helps to delurk some insidious errors.
1350 =item Can't use bareword ("%s") as %s ref while "strict refs" in use
1352 (F) Only hard references are allowed by "strict refs". Symbolic
1353 references are disallowed. See L<perlref>.
1355 =item Can't use %! because Errno.pm is not available
1357 (F) The first time the C<%!> hash is used, perl automatically loads the
1358 Errno.pm module. The Errno module is expected to tie the %! hash to
1359 provide symbolic names for C<$!> errno values.
1361 =item Can't use both '<' and '>' after type '%c' in %s
1363 (F) A type cannot be forced to have both big-endian and little-endian
1364 byte-order at the same time, so this combination of modifiers is not
1365 allowed. See L<perlfunc/pack>.
1367 =item Can't use 'defined(@array)' (Maybe you should just omit the defined()?)
1369 (F) defined() is not useful on arrays because it
1370 checks for an undefined I<scalar> value. If you want to see if the
1371 array is empty, just use C<if (@array) { # not empty }> for example.
1373 =item Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)
1375 (F) C<defined()> is not usually right on hashes.
1377 Although C<defined %hash> is false on a plain not-yet-used hash, it
1378 becomes true in several non-obvious circumstances, including iterators,
1379 weak references, stash names, even remaining true after C<undef %hash>.
1380 These things make C<defined %hash> fairly useless in practice, so it now
1381 generates a fatal error.
1383 If a check for non-empty is what you wanted then just put it in boolean
1384 context (see L<perldata/Scalar values>):
1390 If you had C<defined %Foo::Bar::QUUX> to check whether such a package
1391 variable exists then that's never really been reliable, and isn't
1392 a good way to enquire about the features of a package, or whether
1395 =item Can't use %s for loop variable
1397 (P) The parser got confused when trying to parse a C<foreach> loop.
1399 =item Can't use global %s in "%s"
1401 (F) You tried to declare a magical variable as a lexical variable. This
1402 is not allowed, because the magic can be tied to only one location
1403 (namely the global variable) and it would be incredibly confusing to
1404 have variables in your program that looked like magical variables but
1407 =item Can't use '%c' in a group with different byte-order in %s
1409 (F) You attempted to force a different byte-order on a type
1410 that is already inside a group with a byte-order modifier.
1411 For example you cannot force little-endianness on a type that
1412 is inside a big-endian group.
1414 =item Can't use "my %s" in sort comparison
1416 (F) The global variables $a and $b are reserved for sort comparisons.
1417 You mentioned $a or $b in the same line as the <=> or cmp operator,
1418 and the variable had earlier been declared as a lexical variable.
1419 Either qualify the sort variable with the package name, or rename the
1422 =item Can't use %s ref as %s ref
1424 (F) You've mixed up your reference types. You have to dereference a
1425 reference of the type needed. You can use the ref() function to
1426 test the type of the reference, if need be.
1428 =item Can't use string ("%s") as %s ref while "strict refs" in use
1430 =item Can't use string ("%s"...) as %s ref while "strict refs" in use
1432 (F) You've told Perl to dereference a string, something which
1433 C<use strict> blocks to prevent it happening accidentally. See
1434 L<perlref/"Symbolic references">. This can be triggered by an C<@> or C<$>
1435 in a double-quoted string immediately before interpolating a variable,
1436 for example in C<"user @$twitter_id">, which says to treat the contents
1437 of C<$twitter_id> as an array reference; use a C<\> to have a literal C<@>
1438 symbol followed by the contents of C<$twitter_id>: C<"user \@$twitter_id">.
1440 =item Can't use subscript on %s
1442 (F) The compiler tried to interpret a bracketed expression as a
1443 subscript. But to the left of the brackets was an expression that
1444 didn't look like a hash or array reference, or anything else subscriptable.
1446 =item Can't use \%c to mean $%c in expression
1448 (W syntax) In an ordinary expression, backslash is a unary operator that
1449 creates a reference to its argument. The use of backslash to indicate a
1450 backreference to a matched substring is valid only as part of a regular
1451 expression pattern. Trying to do this in ordinary Perl code produces a
1452 value that prints out looking like SCALAR(0xdecaf). Use the $1 form
1455 =item Can't weaken a nonreference
1457 (F) You attempted to weaken something that was not a reference. Only
1458 references can be weakened.
1460 =item Can't "when" outside a topicalizer
1462 (F) You have used a when() block that is neither inside a C<foreach>
1463 loop nor a C<given> block. (Note that this error is issued on exit
1464 from the C<when> block, so you won't get the error if the match fails,
1465 or if you use an explicit C<continue>.)
1467 =item Can't x= to read-only value
1469 (F) You tried to repeat a constant value (often the undefined value)
1470 with an assignment operator, which implies modifying the value itself.
1471 Perhaps you need to copy the value to a temporary, and repeat that.
1473 =item Character following "\c" must be printable ASCII
1475 (F) In C<\cI<X>>, I<X> must be a printable (non-control) ASCII character.
1477 Note that ASCII characters that don't map to control characters are
1478 discouraged, and will generate the warning (when enabled)
1479 L</""\c%c" is more clearly written simply as "%s"">.
1481 =item Character in 'C' format wrapped in pack
1487 where $x is either less than 0 or more than 255; the C<"C"> format is
1488 only for encoding native operating system characters (ASCII, EBCDIC,
1489 and so on) and not for Unicode characters, so Perl behaved as if you meant
1493 If you actually want to pack Unicode codepoints, use the C<"U"> format
1496 =item Character in 'c' format wrapped in pack
1502 where $x is either less than -128 or more than 127; the C<"c"> format
1503 is only for encoding native operating system characters (ASCII, EBCDIC,
1504 and so on) and not for Unicode characters, so Perl behaved as if you meant
1506 pack("c", $x & 255);
1508 If you actually want to pack Unicode codepoints, use the C<"U"> format
1511 =item Character in '%c' format wrapped in unpack
1513 (W unpack) You tried something like
1515 unpack("H", "\x{2a1}")
1517 where the format expects to process a byte (a character with a value
1518 below 256), but a higher value was provided instead. Perl uses the
1519 value modulus 256 instead, as if you had provided:
1521 unpack("H", "\x{a1}")
1523 =item Character in 'W' format wrapped in pack
1529 where $x is either less than 0 or more than 255. However, C<U0>-mode
1530 expects all values to fall in the interval [0, 255], so Perl behaved
1533 pack("U0W", $x & 255)
1535 =item Character(s) in '%c' format wrapped in pack
1537 (W pack) You tried something like
1539 pack("u", "\x{1f3}b")
1541 where the format expects to process a sequence of bytes (character with a
1542 value below 256), but some of the characters had a higher value. Perl
1543 uses the character values modulus 256 instead, as if you had provided:
1545 pack("u", "\x{f3}b")
1547 =item Character(s) in '%c' format wrapped in unpack
1549 (W unpack) You tried something like
1551 unpack("s", "\x{1f3}b")
1553 where the format expects to process a sequence of bytes (character with a
1554 value below 256), but some of the characters had a higher value. Perl
1555 uses the character values modulus 256 instead, as if you had provided:
1557 unpack("s", "\x{f3}b")
1559 =item charnames alias definitions may not contain a sequence of multiple spaces
1561 (F) You defined a character name which had multiple space characters
1562 in a row. Change them to single spaces. Usually these names are
1563 defined in the C<:alias> import argument to C<use charnames>, but they
1564 could be defined by a translator installed into C<$^H{charnames}>. See
1565 L<charnames/CUSTOM ALIASES>.
1567 =item charnames alias definitions may not contain trailing white-space
1569 (F) You defined a character name which ended in a space
1570 character. Remove the trailing space(s). Usually these names are
1571 defined in the C<:alias> import argument to C<use charnames>, but they
1572 could be defined by a translator installed into C<$^H{charnames}>.
1573 See L<charnames/CUSTOM ALIASES>.
1575 =item chdir() on unopened filehandle %s
1577 (W unopened) You tried chdir() on a filehandle that was never opened.
1579 =item \C no longer supported in regex; marked by S<<-- HERE> in m/%s/
1581 (F) The \C character class used to allow a match of single byte within a
1582 multi-byte utf-8 character, but was removed in v5.24 as it broke
1583 encapsulation and its implementation was extremely buggy. If you really
1584 need to process the individual bytes, you probably want to convert your
1585 string to one where each underlying byte is stored as a character, with
1588 =item "\c%c" is more clearly written simply as "%s"
1590 (W syntax) The C<\cI<X>> construct is intended to be a way to specify
1591 non-printable characters. You used it for a printable one, which
1592 is better written as simply itself, perhaps preceded by a backslash
1593 for non-word characters. Doing it the way you did is not portable
1594 between ASCII and EBCDIC platforms.
1596 =item Cloning substitution context is unimplemented
1598 (F) Creating a new thread inside the C<s///> operator is not supported.
1600 =item closedir() attempted on invalid dirhandle %s
1602 (W io) The dirhandle you tried to close is either closed or not really
1603 a dirhandle. Check your control flow.
1605 =item close() on unopened filehandle %s
1607 (W unopened) You tried to close a filehandle that was never opened.
1609 =item Closure prototype called
1611 (F) If a closure has attributes, the subroutine passed to an attribute
1612 handler is the prototype that is cloned when a new closure is created.
1613 This subroutine cannot be called.
1615 =item Code missing after '/'
1617 (F) You had a (sub-)template that ends with a '/'. There must be
1618 another template code following the slash. See L<perlfunc/pack>.
1620 =item Code point 0x%X is not Unicode, may not be portable
1622 (S non_unicode) You had a code point above the Unicode maximum
1625 Perl allows strings to contain a superset of Unicode code points, up
1626 to the limit of what is storable in an unsigned integer on your system,
1627 but these may not be accepted by other languages/systems. At one time,
1628 it was legal in some standards to have code points up to 0x7FFF_FFFF,
1629 but not higher. Code points above 0xFFFF_FFFF require larger than a
1632 =item %s: Command not found
1634 (A) You've accidentally run your script through B<csh> or another shell
1635 instead of Perl. Check the #! line, or manually feed your script into
1636 Perl yourself. The #! line at the top of your file could look like
1640 =item Compilation failed in require
1642 (F) Perl could not compile a file specified in a C<require> statement.
1643 Perl uses this generic message when none of the errors that it
1644 encountered were severe enough to halt compilation immediately.
1646 =item Complex regular subexpression recursion limit (%d) exceeded
1648 (W regexp) The regular expression engine uses recursion in complex
1649 situations where back-tracking is required. Recursion depth is limited
1650 to 32766, or perhaps less in architectures where the stack cannot grow
1651 arbitrarily. ("Simple" and "medium" situations are handled without
1652 recursion and are not subject to a limit.) Try shortening the string
1653 under examination; looping in Perl code (e.g. with C<while>) rather than
1654 in the regular expression engine; or rewriting the regular expression so
1655 that it is simpler or backtracks less. (See L<perlfaq2> for information
1656 on I<Mastering Regular Expressions>.)
1658 =item connect() on closed socket %s
1660 (W closed) You tried to do a connect on a closed socket. Did you forget
1661 to check the return value of your socket() call? See
1662 L<perlfunc/connect>.
1664 =item Constant(%s): Call to &{$^H{%s}} did not return a defined value
1666 (F) The subroutine registered to handle constant overloading
1667 (see L<overload>) or a custom charnames handler (see
1668 L<charnames/CUSTOM TRANSLATORS>) returned an undefined value.
1670 =item Constant(%s): $^H{%s} is not defined
1672 (F) The parser found inconsistencies while attempting to define an
1673 overloaded constant. Perhaps you forgot to load the corresponding
1676 =item Constant is not %s reference
1678 (F) A constant value (perhaps declared using the C<use constant> pragma)
1679 is being dereferenced, but it amounts to the wrong type of reference.
1680 The message indicates the type of reference that was expected. This
1681 usually indicates a syntax error in dereferencing the constant value.
1682 See L<perlsub/"Constant Functions"> and L<constant>.
1684 =item Constants from lexical variables potentially modified elsewhere are
1687 (D deprecated) You wrote something like
1690 $sub = sub () { $var };
1692 but $var is referenced elsewhere and could be modified after the C<sub>
1693 expression is evaluated. Either it is explicitly modified elsewhere
1694 (C<$var = 3>) or it is passed to a subroutine or to an operator like
1695 C<printf> or C<map>, which may or may not modify the variable.
1697 Traditionally, Perl has captured the value of the variable at that
1698 point and turned the subroutine into a constant eligible for inlining.
1699 In those cases where the variable can be modified elsewhere, this
1700 breaks the behavior of closures, in which the subroutine captures
1701 the variable itself, rather than its value, so future changes to the
1702 variable are reflected in the subroutine's return value.
1704 This usage is deprecated, because the behavior is likely to change
1705 in a future version of Perl.
1707 If you intended for the subroutine to be eligible for inlining, then
1708 make sure the variable is not referenced elsewhere, possibly by
1712 $sub = sub () { $var2 };
1714 If you do want this subroutine to be a closure that reflects future
1715 changes to the variable that it closes over, add an explicit C<return>:
1718 $sub = sub () { return $var };
1720 =item Constant subroutine %s redefined
1722 (W redefine)(S) You redefined a subroutine which had previously
1723 been eligible for inlining. See L<perlsub/"Constant Functions">
1724 for commentary and workarounds.
1726 =item Constant subroutine %s undefined
1728 (W misc) You undefined a subroutine which had previously been eligible
1729 for inlining. See L<perlsub/"Constant Functions"> for commentary and
1732 =item Constant(%s) unknown
1734 (F) The parser found inconsistencies either while attempting
1735 to define an overloaded constant, or when trying to find the
1736 character name specified in the C<\N{...}> escape. Perhaps you
1737 forgot to load the corresponding L<overload> pragma?
1739 =item :const is experimental
1741 (S experimental::const_attr) The "const" attribute is experimental.
1742 If you want to use the feature, disable the warning with C<no warnings
1743 'experimental::const_attr'>, but know that in doing so you are taking
1744 the risk that your code may break in a future Perl version.
1746 =item :const is not permitted on named subroutines
1748 (F) The "const" attribute causes an anonymous subroutine to be run and
1749 its value captured at the time that it is cloned. Named subroutines are
1750 not cloned like this, so the attribute does not make sense on them.
1752 =item Copy method did not return a reference
1754 (F) The method which overloads "=" is buggy. See
1755 L<overload/Copy Constructor>.
1757 =item &CORE::%s cannot be called directly
1759 (F) You tried to call a subroutine in the C<CORE::> namespace
1760 with C<&foo> syntax or through a reference. Some subroutines
1761 in this package cannot yet be called that way, but must be
1762 called as barewords. Something like this will work:
1764 BEGIN { *shove = \&CORE::push; }
1765 shove @array, 1,2,3; # pushes on to @array
1767 =item CORE::%s is not a keyword
1769 (F) The CORE:: namespace is reserved for Perl keywords.
1771 =item Corrupted regexp opcode %d > %d
1773 (P) This is either an error in Perl, or, if you're using
1774 one, your L<custom regular expression engine|perlreapi>. If not the
1775 latter, report the problem through the L<perlbug> utility.
1777 =item corrupted regexp pointers
1779 (P) The regular expression engine got confused by what the regular
1780 expression compiler gave it.
1782 =item corrupted regexp program
1784 (P) The regular expression engine got passed a regexp program without a
1787 =item Corrupt malloc ptr 0x%x at 0x%x
1789 (P) The malloc package that comes with Perl had an internal failure.
1791 =item Count after length/code in unpack
1793 (F) You had an unpack template indicating a counted-length string, but
1794 you have also specified an explicit size for the string. See
1798 The following are used in lib/diagnostics.t for testing two =items that
1799 share the same description. Changes here need to be propagated to there
1801 =item Deep recursion on anonymous subroutine
1803 =item Deep recursion on subroutine "%s"
1805 (W recursion) This subroutine has called itself (directly or indirectly)
1806 100 times more than it has returned. This probably indicates an
1807 infinite recursion, unless you're writing strange benchmark programs, in
1808 which case it indicates something else.
1810 This threshold can be changed from 100, by recompiling the F<perl> binary,
1811 setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1813 =item (?(DEFINE)....) does not allow branches in regex; marked by
1814 S<<-- HERE> in m/%s/
1816 (F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
1817 most likely cause of this error is that you left out a parenthesis inside
1818 of the C<....> part.
1820 The S<<-- HERE> shows whereabouts in the regular expression the problem was
1823 =item %s defines neither package nor VERSION--version check failed
1825 (F) You said something like "use Module 42" but in the Module file
1826 there are neither package declarations nor a C<$VERSION>.
1828 =item delete argument is index/value array slice, use array slice
1830 (F) You used index/value array slice syntax (C<%array[...]>) as
1831 the argument to C<delete>. You probably meant C<@array[...]> with
1832 an @ symbol instead.
1834 =item delete argument is key/value hash slice, use hash slice
1836 (F) You used key/value hash slice syntax (C<%hash{...}>) as the argument to
1837 C<delete>. You probably meant C<@hash{...}> with an @ symbol instead.
1839 =item delete argument is not a HASH or ARRAY element or slice
1841 (F) The argument to C<delete> must be either a hash or array element,
1847 or a hash or array slice, such as:
1849 @foo[$bar, $baz, $xyzzy]
1850 @{$ref->[12]}{"susie", "queue"}
1852 =item Delimiter for here document is too long
1854 (F) In a here document construct like C<<<FOO>, the label C<FOO> is too
1855 long for Perl to handle. You have to be seriously twisted to write code
1856 that triggers this error.
1858 =item Deprecated use of my() in false conditional
1860 (D deprecated) You used a declaration similar to C<my $x if 0>. There
1861 has been a long-standing bug in Perl that causes a lexical variable
1862 not to be cleared at scope exit when its declaration includes a false
1863 conditional. Some people have exploited this bug to achieve a kind of
1864 static variable. Since we intend to fix this bug, we don't want people
1865 relying on this behavior. You can achieve a similar static effect by
1866 declaring the variable in a separate block outside the function, eg
1868 sub f { my $x if 0; return $x++ }
1872 { my $x; sub f { return $x++ } }
1874 Beginning with perl 5.10.0, you can also use C<state> variables to have
1875 lexicals that are initialized only once (see L<feature>):
1877 sub f { state $x; return $x++ }
1879 =item DESTROY created new reference to dead object '%s'
1881 (F) A DESTROY() method created a new reference to the object which is
1882 just being DESTROYed. Perl is confused, and prefers to abort rather
1883 than to create a dangling reference.
1885 =item Did not produce a valid header
1889 =item %s did not return a true value
1891 (F) A required (or used) file must return a true value to indicate that
1892 it compiled correctly and ran its initialization code correctly. It's
1893 traditional to end such a file with a "1;", though any true value would
1894 do. See L<perlfunc/require>.
1896 =item (Did you mean &%s instead?)
1898 (W misc) You probably referred to an imported subroutine &FOO as $FOO or
1901 =item (Did you mean "local" instead of "our"?)
1903 (W misc) Remember that "our" does not localize the declared global
1904 variable. You have declared it again in the same lexical scope, which
1907 =item (Did you mean $ or @ instead of %?)
1909 (W) You probably said %hash{$key} when you meant $hash{$key} or
1910 @hash{@keys}. On the other hand, maybe you just meant %hash and got
1915 (F) You passed die() an empty string (the equivalent of C<die "">) or
1916 you called it with no args and C<$@> was empty.
1918 =item Document contains no data
1922 =item %s does not define %s::VERSION--version check failed
1924 (F) You said something like "use Module 42" but the Module did not
1925 define a C<$VERSION>.
1927 =item '/' does not take a repeat count
1929 (F) You cannot put a repeat count of any kind right after the '/' code.
1930 See L<perlfunc/pack>.
1932 =item Don't know how to get file name
1934 (P) C<PerlIO_getname>, a perl internal I/O function specific to VMS, was
1935 somehow called on another platform. This should not happen.
1937 =item Don't know how to handle magic of type \%o
1939 (P) The internal handling of magical variables has been cursed.
1941 =item do_study: out of memory
1943 (P) This should have been caught by safemalloc() instead.
1945 =item (Do you need to predeclare %s?)
1947 (S syntax) This is an educated guess made in conjunction with the message
1948 "%s found where operator expected". It often means a subroutine or module
1949 name is being referenced that hasn't been declared yet. This may be
1950 because of ordering problems in your file, or because of a missing
1951 "sub", "package", "require", or "use" statement. If you're referencing
1952 something that isn't defined yet, you don't actually have to define the
1953 subroutine or package before the current location. You can use an empty
1954 "sub foo;" or "package FOO;" to enter a "forward" declaration.
1956 =item dump() better written as CORE::dump()
1958 (W misc) You used the obsolescent C<dump()> built-in function, without fully
1959 qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
1961 =item dump is not supported
1963 (F) Your machine doesn't support dump/undump.
1965 =item Duplicate free() ignored
1967 (S malloc) An internal routine called free() on something that had
1970 =item Duplicate modifier '%c' after '%c' in %s
1972 (W unpack) You have applied the same modifier more than once after a
1973 type in a pack template. See L<perlfunc/pack>.
1975 =item elseif should be elsif
1977 (S syntax) There is no keyword "elseif" in Perl because Larry thinks
1978 it's ugly. Your code will be interpreted as an attempt to call a method
1979 named "elseif" for the class returned by the following block. This is
1980 unlikely to be what you want.
1982 =item Empty \%c{} in regex; marked by S<<-- HERE> in m/%s/
1984 (F) C<\p> and C<\P> are used to introduce a named Unicode property, as
1985 described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
1986 a regular expression without specifying the property name.
1988 =item entering effective %s failed
1990 (F) While under the C<use filetest> pragma, switching the real and
1991 effective uids or gids failed.
1993 =item %ENV is aliased to %s
1995 (F) You're running under taint mode, and the C<%ENV> variable has been
1996 aliased to another hash, so it doesn't reflect anymore the state of the
1997 program's environment. This is potentially insecure.
1999 =item Error converting file specification %s
2001 (F) An error peculiar to VMS. Because Perl may have to deal with file
2002 specifications in either VMS or Unix syntax, it converts them to a
2003 single form when it must operate on them directly. Either you've passed
2004 an invalid file specification to Perl, or you've found a case the
2005 conversion routines don't handle. Drat.
2007 =item Eval-group in insecure regular expression
2009 (F) Perl detected tainted data when trying to compile a regular
2010 expression that contains the C<(?{ ... })> zero-width assertion, which
2011 is unsafe. See L<perlre/(?{ code })>, and L<perlsec>.
2013 =item Eval-group not allowed at runtime, use re 'eval' in regex m/%s/
2015 (F) Perl tried to compile a regular expression containing the
2016 C<(?{ ... })> zero-width assertion at run time, as it would when the
2017 pattern contains interpolated values. Since that is a security risk,
2018 it is not allowed. If you insist, you may still do this by using the
2019 C<re 'eval'> pragma or by explicitly building the pattern from an
2020 interpolated string at run time and using that in an eval(). See
2021 L<perlre/(?{ code })>.
2023 =item Eval-group not allowed, use re 'eval' in regex m/%s/
2025 (F) A regular expression contained the C<(?{ ... })> zero-width
2026 assertion, but that construct is only allowed when the C<use re 'eval'>
2027 pragma is in effect. See L<perlre/(?{ code })>.
2029 =item EVAL without pos change exceeded limit in regex; marked by
2030 S<<-- HERE> in m/%s/
2032 (F) You used a pattern that nested too many EVAL calls without consuming
2033 any text. Restructure the pattern so that text is consumed.
2035 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2038 =item Excessively long <> operator
2040 (F) The contents of a <> operator may not exceed the maximum size of a
2041 Perl identifier. If you're just trying to glob a long list of
2042 filenames, try using the glob() operator, or put the filenames into a
2043 variable and glob that.
2045 =item exec? I'm not *that* kind of operating system
2047 (F) The C<exec> function is not implemented on some systems, e.g., Symbian
2048 OS. See L<perlport>.
2050 =item Execution of %s aborted due to compilation errors.
2052 (F) The final summary message when a Perl compilation fails.
2054 =item exists argument is not a HASH or ARRAY element or a subroutine
2056 (F) The argument to C<exists> must be a hash or array element or a
2057 subroutine with an ampersand, such as:
2063 =item exists argument is not a subroutine name
2065 (F) The argument to C<exists> for C<exists &sub> must be a subroutine name,
2066 and not a subroutine call. C<exists &sub()> will generate this error.
2068 =item Exiting eval via %s
2070 (W exiting) You are exiting an eval by unconventional means, such as a
2071 goto, or a loop control statement.
2073 =item Exiting format via %s
2075 (W exiting) You are exiting a format by unconventional means, such as a
2076 goto, or a loop control statement.
2078 =item Exiting pseudo-block via %s
2080 (W exiting) You are exiting a rather special block construct (like a
2081 sort block or subroutine) by unconventional means, such as a goto, or a
2082 loop control statement. See L<perlfunc/sort>.
2084 =item Exiting subroutine via %s
2086 (W exiting) You are exiting a subroutine by unconventional means, such
2087 as a goto, or a loop control statement.
2089 =item Exiting substitution via %s
2091 (W exiting) You are exiting a substitution by unconventional means, such
2092 as a return, a goto, or a loop control statement.
2094 =item Expecting close bracket in regex; marked by S<<-- HERE> in m/%s/
2096 (F) You wrote something like
2100 to denote a capturing group of the form
2101 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>,
2102 but omitted the C<")">.
2104 =item Expecting '(?flags:(?[...' in regex; marked by S<<-- HERE> in m/%s/
2106 (F) The C<(?[...])> extended character class regular expression construct
2107 only allows character classes (including character class escapes like
2108 C<\d>), operators, and parentheses. The one exception is C<(?flags:...)>
2109 containing at least one flag and exactly one C<(?[...])> construct.
2110 This allows a regular expression containing just C<(?[...])> to be
2111 interpolated. If you see this error message, then you probably
2112 have some other C<(?...)> construct inside your character class. See
2113 L<perlrecharclass/Extended Bracketed Character Classes>.
2115 =item Experimental aliasing via reference not enabled
2117 (F) To do aliasing via references, you must first enable the feature:
2119 no warnings "experimental::refaliasing";
2120 use feature "refaliasing";
2123 =item Experimental subroutine signatures not enabled
2125 (F) To use subroutine signatures, you must first enable them:
2127 no warnings "experimental::signatures";
2128 use feature "signatures";
2129 sub foo ($left, $right) { ... }
2131 =item Experimental %s on scalar is now forbidden
2133 (F) An experimental feature added in Perl 5.14 allowed C<each>, C<keys>,
2134 C<push>, C<pop>, C<shift>, C<splice>, C<unshift>, and C<values> to be called
2135 with a scalar argument. This experiment is considered unsuccessful, and has
2136 been removed. The C<postderef> feature may meet your needs better.
2138 =item Experimental "%s" subs not enabled
2140 (F) To use lexical subs, you must first enable them:
2142 no warnings 'experimental::lexical_subs';
2143 use feature 'lexical_subs';
2146 =item Explicit blessing to '' (assuming package main)
2148 (W misc) You are blessing a reference to a zero length string. This has
2149 the effect of blessing the reference into the package main. This is
2150 usually not what you want. Consider providing a default target package,
2151 e.g. bless($ref, $p || 'MyPackage');
2153 =item %s: Expression syntax
2155 (A) You've accidentally run your script through B<csh> instead of Perl.
2156 Check the #! line, or manually feed your script into Perl yourself.
2158 =item %s failed--call queue aborted
2160 (F) An untrapped exception was raised while executing a UNITCHECK,
2161 CHECK, INIT, or END subroutine. Processing of the remainder of the
2162 queue of such routines has been prematurely ended.
2164 =item False [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2166 (W regexp)(F) A character class range must start and end at a literal
2167 character, not another character class like C<\d> or C<[:alpha:]>. The "-"
2168 in your false range is interpreted as a literal "-". In a C<(?[...])>
2169 construct, this is an error, rather than a warning. Consider quoting
2170 the "-", "\-". The S<<-- HERE> shows whereabouts in the regular expression
2171 the problem was discovered. See L<perlre>.
2173 =item Fatal VMS error (status=%d) at %s, line %d
2175 (P) An error peculiar to VMS. Something untoward happened in a VMS
2176 system service or RTL routine; Perl's exit status should provide more
2177 details. The filename in "at %s" and the line number in "line %d" tell
2178 you which section of the Perl source code is distressed.
2180 =item fcntl is not implemented
2182 (F) Your machine apparently doesn't implement fcntl(). What is this, a
2183 PDP-11 or something?
2185 =item FETCHSIZE returned a negative value
2187 (F) A tied array claimed to have a negative number of elements, which
2190 =item Field too wide in 'u' format in pack
2192 (W pack) Each line in an uuencoded string starts with a length indicator
2193 which can't encode values above 63. So there is no point in asking for
2194 a line length bigger than that. Perl will behave as if you specified
2195 C<u63> as the format.
2197 =item Filehandle %s opened only for input
2199 (W io) You tried to write on a read-only filehandle. If you intended
2200 it to be a read-write filehandle, you needed to open it with "+<" or
2201 "+>" or "+>>" instead of with "<" or nothing. If you intended only to
2202 write the file, use ">" or ">>". See L<perlfunc/open>.
2204 =item Filehandle %s opened only for output
2206 (W io) You tried to read from a filehandle opened only for writing, If
2207 you intended it to be a read/write filehandle, you needed to open it
2208 with "+<" or "+>" or "+>>" instead of with ">". If you intended only to
2209 read from the file, use "<". See L<perlfunc/open>. Another possibility
2210 is that you attempted to open filedescriptor 0 (also known as STDIN) for
2211 output (maybe you closed STDIN earlier?).
2213 =item Filehandle %s reopened as %s only for input
2215 (W io) You opened for reading a filehandle that got the same filehandle id
2216 as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR
2219 =item Filehandle STDIN reopened as %s only for output
2221 (W io) You opened for writing a filehandle that got the same filehandle id
2222 as STDIN. This occurred because you closed STDIN previously.
2224 =item Final $ should be \$ or $name
2226 (F) You must now decide whether the final $ in a string was meant to be
2227 a literal dollar sign, or was meant to introduce a variable name that
2228 happens to be missing. So you have to put either the backslash or the
2231 =item flock() on closed filehandle %s
2233 (W closed) The filehandle you're attempting to flock() got itself closed
2234 some time before now. Check your control flow. flock() operates on
2235 filehandles. Are you attempting to call flock() on a dirhandle by the
2238 =item Format not terminated
2240 (F) A format must be terminated by a line with a solitary dot. Perl got
2241 to the end of your file without finding such a line.
2243 =item Format %s redefined
2245 (W redefine) You redefined a format. To suppress this warning, say
2248 no warnings 'redefine';
2249 eval "format NAME =...";
2252 =item Found = in conditional, should be ==
2262 (or something like that).
2264 =item %s found where operator expected
2266 (S syntax) The Perl lexer knows whether to expect a term or an operator.
2267 If it sees what it knows to be a term when it was expecting to see an
2268 operator, it gives you this warning. Usually it indicates that an
2269 operator or delimiter was omitted, such as a semicolon.
2271 =item gdbm store returned %d, errno %d, key "%s"
2273 (S) A warning from the GDBM_File extension that a store failed.
2275 =item gethostent not implemented
2277 (F) Your C library apparently doesn't implement gethostent(), probably
2278 because if it did, it'd feel morally obligated to return every hostname
2281 =item get%sname() on closed socket %s
2283 (W closed) You tried to get a socket or peer socket name on a closed
2284 socket. Did you forget to check the return value of your socket() call?
2286 =item getpwnam returned invalid UIC %#o for user "%s"
2288 (S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
2289 C<getpwnam> operator returned an invalid UIC.
2291 =item getsockopt() on closed socket %s
2293 (W closed) You tried to get a socket option on a closed socket. Did you
2294 forget to check the return value of your socket() call? See
2295 L<perlfunc/getsockopt>.
2297 =item given is experimental
2299 (S experimental::smartmatch) C<given> depends on smartmatch, which
2300 is experimental, so its behavior may change or even be removed
2301 in any future release of perl. See the explanation under
2302 L<perlsyn/Experimental Details on given and when>.
2304 =item Global symbol "%s" requires explicit package name (did you forget to
2307 (F) You've said "use strict" or "use strict vars", which indicates
2308 that all variables must either be lexically scoped (using "my" or "state"),
2309 declared beforehand using "our", or explicitly qualified to say
2310 which package the global variable is in (using "::").
2312 =item glob failed (%s)
2314 (S glob) Something went wrong with the external program(s) used
2315 for C<glob> and C<< <*.c> >>. Usually, this means that you supplied a C<glob>
2316 pattern that caused the external program to fail and exit with a
2317 nonzero status. If the message indicates that the abnormal exit
2318 resulted in a coredump, this may also mean that your csh (C shell)
2319 is broken. If so, you should change all of the csh-related variables
2320 in config.sh: If you have tcsh, make the variables refer to it as
2321 if it were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them
2322 all empty (except that C<d_csh> should be C<'undef'>) so that Perl will
2323 think csh is missing. In either case, after editing config.sh, run
2324 C<./Configure -S> and rebuild Perl.
2326 =item Glob not terminated
2328 (F) The lexer saw a left angle bracket in a place where it was expecting
2329 a term, so it's looking for the corresponding right angle bracket, and
2330 not finding it. Chances are you left some needed parentheses out
2331 earlier in the line, and you really meant a "less than".
2333 =item gmtime(%f) failed
2335 (W overflow) You called C<gmtime> with a number that it could not handle:
2336 too large, too small, or NaN. The returned value is C<undef>.
2338 =item gmtime(%f) too large
2340 (W overflow) You called C<gmtime> with a number that was larger than
2341 it can reliably handle and C<gmtime> probably returned the wrong
2342 date. This warning is also triggered with NaN (the special
2343 not-a-number value).
2345 =item gmtime(%f) too small
2347 (W overflow) You called C<gmtime> with a number that was smaller than
2348 it can reliably handle and C<gmtime> probably returned the wrong date.
2350 =item Got an error from DosAllocMem
2352 (P) An error peculiar to OS/2. Most probably you're using an obsolete
2353 version of Perl, and this should not happen anyway.
2355 =item goto must have label
2357 (F) Unlike with "next" or "last", you're not allowed to goto an
2358 unspecified destination. See L<perlfunc/goto>.
2360 =item Goto undefined subroutine%s
2362 (F) You tried to call a subroutine with C<goto &sub> syntax, but
2363 the indicated subroutine hasn't been defined, or if it was, it
2364 has since been undefined.
2366 =item Group name must start with a non-digit word character in regex; marked by
2367 S<<-- HERE> in m/%s/
2369 (F) Group names must follow the rules for perl identifiers, meaning
2370 they must start with a non-digit word character. A common cause of
2371 this error is using (?&0) instead of (?0). See L<perlre>.
2373 =item ()-group starts with a count
2375 (F) A ()-group started with a count. A count is supposed to follow
2376 something: a template character or a ()-group. See L<perlfunc/pack>.
2378 =item %s had compilation errors.
2380 (F) The final summary message when a C<perl -c> fails.
2382 =item Had to create %s unexpectedly
2384 (S internal) A routine asked for a symbol from a symbol table that ought
2385 to have existed already, but for some reason it didn't, and had to be
2386 created on an emergency basis to prevent a core dump.
2388 =item %s has too many errors
2390 (F) The parser has given up trying to parse the program after 10 errors.
2391 Further error messages would likely be uninformative.
2393 =item Having more than one /%c regexp modifier is deprecated
2395 (D deprecated, regexp) You used the indicated regular expression pattern
2396 modifier at least twice in a string of modifiers. It is deprecated to
2397 do this with this particular modifier, to allow future extensions to the
2400 =item Hexadecimal float: exponent overflow
2402 (W overflow) The hexadecimal floating point has a larger exponent
2403 than the floating point supports.
2405 =item Hexadecimal float: exponent underflow
2407 (W overflow) The hexadecimal floating point has a smaller exponent
2408 than the floating point supports.
2410 =item Hexadecimal float: internal error (%s)
2412 (F) Something went horribly bad in hexadecimal float handling.
2414 =item Hexadecimal float: mantissa overflow
2416 (W overflow) The hexadecimal floating point literal had more bits in
2417 the mantissa (the part between the 0x and the exponent, also known as
2418 the fraction or the significand) than the floating point supports.
2420 =item Hexadecimal float: precision loss
2422 (W overflow) The hexadecimal floating point had internally more
2423 digits than could be output. This can be caused by unsupported
2424 long double formats, or by 64-bit integers not being available
2425 (needed to retrieve the digits under some configurations).
2427 =item Hexadecimal float: unsupported long double format
2429 (F) You have configured Perl to use long doubles but
2430 the internals of the long double format are unknown;
2431 therefore the hexadecimal float output is impossible.
2433 =item Hexadecimal number > 0xffffffff non-portable
2435 (W portable) The hexadecimal number you specified is larger than 2**32-1
2436 (4294967295) and therefore non-portable between systems. See
2437 L<perlport> for more on portability concerns.
2439 =item Identifier too long
2441 (F) Perl limits identifiers (names for variables, functions, etc.) to
2442 about 250 characters for simple names, and somewhat more for compound
2443 names (like C<$A::B>). You've exceeded Perl's limits. Future versions
2444 of Perl are likely to eliminate these arbitrary limitations.
2446 =item Ignoring zero length \N{} in character class in regex; marked by
2447 S<<-- HERE> in m/%s/
2449 (W regexp) Named Unicode character escapes (C<\N{...}>) may return a
2450 zero-length sequence. When such an escape is used in a character
2451 class its behavior is not well defined. Check that the correct
2452 escape has been used, and the correct charname handler is in scope.
2454 =item Illegal binary digit %s
2456 (F) You used a digit other than 0 or 1 in a binary number.
2458 =item Illegal binary digit %s ignored
2460 (W digit) You may have tried to use a digit other than 0 or 1 in a
2461 binary number. Interpretation of the binary number stopped before the
2464 =item Illegal character after '_' in prototype for %s : %s
2466 (W illegalproto) An illegal character was found in a prototype
2467 declaration. The '_' in a prototype must be followed by a ';',
2468 indicating the rest of the parameters are optional, or one of '@'
2469 or '%', since those two will accept 0 or more final parameters.
2471 =item Illegal character \%o (carriage return)
2473 (F) Perl normally treats carriage returns in the program text as it
2474 would any other whitespace, which means you should never see this error
2475 when Perl was built using standard options. For some reason, your
2476 version of Perl appears to have been built without this support. Talk
2477 to your Perl administrator.
2479 =item Illegal character in prototype for %s : %s
2481 (W illegalproto) An illegal character was found in a prototype declaration.
2482 Legal characters in prototypes are $, @, %, *, ;, [, ], &, \, and +.
2483 Perhaps you were trying to write a subroutine signature but didn't enable
2484 that feature first (C<use feature 'signatures'>), so your signature was
2485 instead interpreted as a bad prototype.
2487 =item Illegal declaration of anonymous subroutine
2489 (F) When using the C<sub> keyword to construct an anonymous subroutine,
2490 you must always specify a block of code. See L<perlsub>.
2492 =item Illegal declaration of subroutine %s
2494 (F) A subroutine was not declared correctly. See L<perlsub>.
2496 =item Illegal division by zero
2498 (F) You tried to divide a number by 0. Either something was wrong in
2499 your logic, or you need to put a conditional in to guard against
2502 =item Illegal hexadecimal digit %s ignored
2504 (W digit) You may have tried to use a character other than 0 - 9 or
2505 A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
2506 number stopped before the illegal character.
2508 =item Illegal modulus zero
2510 (F) You tried to divide a number by 0 to get the remainder. Most
2511 numbers don't take to this kindly.
2513 =item Illegal number of bits in vec
2515 (F) The number of bits in vec() (the third argument) must be a power of
2516 two from 1 to 32 (or 64, if your platform supports that).
2518 =item Illegal octal digit %s
2520 (F) You used an 8 or 9 in an octal number.
2522 =item Illegal octal digit %s ignored
2524 (W digit) You may have tried to use an 8 or 9 in an octal number.
2525 Interpretation of the octal number stopped before the 8 or 9.
2527 =item Illegal pattern in regex; marked by S<<-- HERE> in m/%s/
2529 (F) You wrote something like
2533 The C<"+"> is valid only when followed by digits, indicating a
2534 capturing group. See
2535 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
2537 =item Illegal suidscript
2539 (F) The script run under suidperl was somehow illegal.
2541 =item Illegal switch in PERL5OPT: -%c
2543 (X) The PERL5OPT environment variable may only be used to set the
2544 following switches: B<-[CDIMUdmtw]>.
2546 =item Ill-formed CRTL environ value "%s"
2548 (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
2549 internal environ array, and encountered an element without the C<=>
2550 delimiter used to separate keys from values. The element is ignored.
2552 =item Ill-formed message in prime_env_iter: |%s|
2554 (W internal) A warning peculiar to VMS. Perl tried to read a logical
2555 name or CLI symbol definition when preparing to iterate over %ENV, and
2556 didn't see the expected delimiter between key and value, so the line was
2559 =item (in cleanup) %s
2561 (W misc) This prefix usually indicates that a DESTROY() method raised
2562 the indicated exception. Since destructors are usually called by the
2563 system at arbitrary points during execution, and often a vast number of
2564 times, the warning is issued only once for any number of failures that
2565 would otherwise result in the same message being repeated.
2567 Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
2568 also result in this warning. See L<perlcall/G_KEEPERR>.
2570 =item Incomplete expression within '(?[ ])' in regex; marked by S<<-- HERE>
2573 (F) There was a syntax error within the C<(?[ ])>. This can happen if the
2574 expression inside the construct was completely empty, or if there are
2575 too many or few operands for the number of operators. Perl is not smart
2576 enough to give you a more precise indication as to what is wrong.
2578 =item Inconsistent hierarchy during C3 merge of class '%s': merging failed on
2581 (F) The method resolution order (MRO) of the given class is not
2582 C3-consistent, and you have enabled the C3 MRO for this class. See the C3
2583 documentation in L<mro> for more information.
2585 =item In EBCDIC the v-string components cannot exceed 2147483647
2587 (F) An error peculiar to EBCDIC. Internally, v-strings are stored as
2588 Unicode code points, and encoded in EBCDIC as UTF-EBCDIC. The UTF-EBCDIC
2589 encoding is limited to code points no larger than 2147483647 (0x7FFFFFFF).
2591 =item Infinite recursion in regex
2593 (F) You used a pattern that references itself without consuming any input
2594 text. You should check the pattern to ensure that recursive patterns
2595 either consume text or fail.
2597 =item Initialization of state variables in list context currently forbidden
2599 (F) Currently the implementation of "state" only permits the
2600 initialization of scalar variables in scalar context. Re-write
2601 C<state ($a) = 42> as C<state $a = 42> to change from list to scalar
2602 context. Constructions such as C<state (@a) = foo()> will be
2603 supported in a future perl release.
2605 =item %%s[%s] in scalar context better written as $%s[%s]
2607 (W syntax) In scalar context, you've used an array index/value slice
2608 (indicated by %) to select a single element of an array. Generally
2609 it's better to ask for a scalar value (indicated by $). The difference
2610 is that C<$foo[&bar]> always behaves like a scalar, both in the value it
2611 returns and when evaluating its argument, while C<%foo[&bar]> provides
2612 a list context to its subscript, which can do weird things if you're
2613 expecting only one subscript. When called in list context, it also
2614 returns the index (what C<&bar> returns) in addition to the value.
2616 =item %%s{%s} in scalar context better written as $%s{%s}
2618 (W syntax) In scalar context, you've used a hash key/value slice
2619 (indicated by %) to select a single element of a hash. Generally it's
2620 better to ask for a scalar value (indicated by $). The difference
2621 is that C<$foo{&bar}> always behaves like a scalar, both in the value
2622 it returns and when evaluating its argument, while C<@foo{&bar}> and
2623 provides a list context to its subscript, which can do weird things
2624 if you're expecting only one subscript. When called in list context,
2625 it also returns the key in addition to the value.
2627 =item %s() is deprecated on :utf8 handles
2629 (W deprecated) The sysread(), recv(), syswrite() and send() operators
2630 are deprecated on handles that have the C<:utf8> layer, either
2631 explicitly, or implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
2633 Both sysread() and recv() currently use only the C<:utf8> flag for the
2634 stream, ignoring the actual layers. Since sysread() and recv() do no
2635 UTF-8 validation they can end up creating invalidly encoded scalars.
2637 Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise
2638 ignoring any layers. If the flag is set, both write the value UTF-8
2639 encoded, even if the layer is some different encoding, such as the
2642 Ideally, all of these operators would completely ignore the C<:utf8>
2643 state, working only with bytes, but this would result in silently
2644 breaking existing code. To avoid this a future version of perl will
2645 throw an exception when any of sysread(), recv(), syswrite() or send()
2646 are called on handle with the C<:utf8> layer.
2648 =item Insecure dependency in %s
2650 (F) You tried to do something that the tainting mechanism didn't like.
2651 The tainting mechanism is turned on when you're running setuid or
2652 setgid, or when you specify B<-T> to turn it on explicitly. The
2653 tainting mechanism labels all data that's derived directly or indirectly
2654 from the user, who is considered to be unworthy of your trust. If any
2655 such data is used in a "dangerous" operation, you get this error. See
2656 L<perlsec> for more information.
2658 =item Insecure directory in %s
2660 (F) You can't use system(), exec(), or a piped open in a setuid or
2661 setgid script if C<$ENV{PATH}> contains a directory that is writable by
2662 the world. Also, the PATH must not contain any relative directory.
2665 =item Insecure $ENV{%s} while running %s
2667 (F) You can't use system(), exec(), or a piped open in a setuid or
2668 setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
2669 C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
2670 supplied (or potentially supplied) by the user. The script must set
2671 the path to a known value, using trustworthy data. See L<perlsec>.
2673 =item Insecure user-defined property %s
2675 (F) Perl detected tainted data when trying to compile a regular
2676 expression that contains a call to a user-defined character property
2677 function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2678 See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
2680 =item Integer overflow in format string for %s
2682 (F) The indexes and widths specified in the format string of C<printf()>
2683 or C<sprintf()> are too large. The numbers must not overflow the size of
2684 integers for your architecture.
2686 =item Integer overflow in %s number
2688 (S overflow) The hexadecimal, octal or binary number you have specified
2689 either as a literal or as an argument to hex() or oct() is too big for
2690 your architecture, and has been converted to a floating point number.
2691 On a 32-bit architecture the largest hexadecimal, octal or binary number
2692 representable without overflow is 0xFFFFFFFF, 037777777777, or
2693 0b11111111111111111111111111111111 respectively. Note that Perl
2694 transparently promotes all numbers to a floating point representation
2695 internally--subject to loss of precision errors in subsequent
2698 =item Integer overflow in srand
2700 (S overflow) The number you have passed to srand is too big to fit
2701 in your architecture's integer representation. The number has been
2702 replaced with the largest integer supported (0xFFFFFFFF on 32-bit
2703 architectures). This means you may be getting less randomness than
2704 you expect, because different random seeds above the maximum will
2705 return the same sequence of random numbers.
2707 =item Integer overflow in version
2709 =item Integer overflow in version %d
2711 (W overflow) Some portion of a version initialization is too large for
2712 the size of integers for your architecture. This is not a warning
2713 because there is no rational reason for a version to try and use an
2714 element larger than typically 2**32. This is usually caused by trying
2715 to use some odd mathematical operation as a version, like 100/9.
2717 =item Internal disaster in regex; marked by S<<-- HERE> in m/%s/
2719 (P) Something went badly wrong in the regular expression parser.
2720 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2723 =item Internal inconsistency in tracking vforks
2725 (S) A warning peculiar to VMS. Perl keeps track of the number of times
2726 you've called C<fork> and C<exec>, to determine whether the current call
2727 to C<exec> should affect the current script or a subprocess (see
2728 L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
2729 Perl is making a guess and treating this C<exec> as a request to
2730 terminate the Perl script and execute the specified command.
2732 =item internal %<num>p might conflict with future printf extensions
2734 (S internal) Perl's internal routine that handles C<printf> and C<sprintf>
2735 formatting follows a slightly different set of rules when called from
2736 C or XS code. Specifically, formats consisting of digits followed
2737 by "p" (e.g., "%7p") are reserved for future use. If you see this
2738 message, then an XS module tried to call that routine with one such
2741 =item Internal urp in regex; marked by S<<-- HERE> in m/%s/
2743 (P) Something went badly awry in the regular expression parser. The
2744 S<<-- HERE> shows whereabouts in the regular expression the problem was
2747 =item %s (...) interpreted as function
2749 (W syntax) You've run afoul of the rule that says that any list operator
2750 followed by parentheses turns into a function, with all the list
2751 operators arguments found inside the parentheses. See
2752 L<perlop/Terms and List Operators (Leftward)>.
2754 =item In '(?...)', the '(' and '?' must be adjacent in regex;
2755 marked by S<<-- HERE> in m/%s/
2757 (F) The two-character sequence C<"(?"> in this context in a regular
2758 expression pattern should be an indivisible token, with nothing
2759 intervening between the C<"("> and the C<"?">, but you separated them
2762 =item Invalid %s attribute: %s
2764 (F) The indicated attribute for a subroutine or variable was not recognized
2765 by Perl or by a user-supplied handler. See L<attributes>.
2767 =item Invalid %s attributes: %s
2769 (F) The indicated attributes for a subroutine or variable were not
2770 recognized by Perl or by a user-supplied handler. See L<attributes>.
2772 =item Invalid character in charnames alias definition; marked by
2775 (F) You tried to create a custom alias for a character name, with
2776 the C<:alias> option to C<use charnames> and the specified character in
2777 the indicated name isn't valid. See L<charnames/CUSTOM ALIASES>.
2779 =item Invalid \0 character in %s for %s: %s\0%s
2781 (W syscalls) Embedded \0 characters in pathnames or other system call
2782 arguments produce a warning as of 5.20. The parts after the \0 were
2783 formerly ignored by system calls.
2785 =item Invalid character in \N{...}; marked by S<<-- HERE> in \N{%s}
2787 (F) Only certain characters are valid for character names. The
2788 indicated one isn't. See L<charnames/CUSTOM ALIASES>.
2790 =item Invalid conversion in %s: "%s"
2792 (W printf) Perl does not understand the given format conversion. See
2793 L<perlfunc/sprintf>.
2795 =item Invalid escape in the specified encoding in regex; marked by
2796 S<<-- HERE> in m/%s/
2798 (W regexp)(F) The numeric escape (for example C<\xHH>) of value < 256
2799 didn't correspond to a single character through the conversion
2800 from the encoding specified by the encoding pragma.
2801 The escape was replaced with REPLACEMENT CHARACTER (U+FFFD)
2802 instead, except within S<C<(?[ ])>>, where it is a fatal error.
2803 The S<<-- HERE> shows whereabouts in the regular expression the
2804 escape was discovered.
2806 =item Invalid hexadecimal number in \N{U+...}
2808 =item Invalid hexadecimal number in \N{U+...} in regex; marked by
2809 S<<-- HERE> in m/%s/
2811 (F) The character constant represented by C<...> is not a valid hexadecimal
2812 number. Either it is empty, or you tried to use a character other than
2813 0 - 9 or A - F, a - f in a hexadecimal number.
2815 =item Invalid module name %s with -%c option: contains single ':'
2817 (F) The module argument to perl's B<-m> and B<-M> command-line options
2818 cannot contain single colons in the module name, but only in the
2819 arguments after "=". In other words, B<-MFoo::Bar=:baz> is ok, but
2820 B<-MFoo:Bar=baz> is not.
2822 =item Invalid mro name: '%s'
2824 (F) You tried to C<mro::set_mro("classname", "foo")> or C<use mro 'foo'>,
2825 where C<foo> is not a valid method resolution order (MRO). Currently,
2826 the only valid ones supported are C<dfs> and C<c3>, unless you have loaded
2827 a module that is a MRO plugin. See L<mro> and L<perlmroapi>.
2829 =item Invalid negative number (%s) in chr
2831 (W utf8) You passed a negative number to C<chr>. Negative numbers are
2832 not valid character numbers, so it returns the Unicode replacement
2835 =item invalid option -D%c, use -D'' to see choices
2837 (S debugging) Perl was called with invalid debugger flags. Call perl
2838 with the B<-D> option with no flags to see the list of acceptable values.
2839 See also L<perlrun/-Dletters>.
2841 =item Invalid quantifier in {,} in regex; marked by S<<-- HERE> in m/%s/
2843 (F) The pattern looks like a {min,max} quantifier, but the min or max
2844 could not be parsed as a valid number - either it has leading zeroes,
2845 or it represents too big a number to cope with. The S<<-- HERE> shows
2846 where in the regular expression the problem was discovered. See L<perlre>.
2848 =item Invalid [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2850 (F) The range specified in a character class had a minimum character
2851 greater than the maximum character. One possibility is that you forgot the
2852 C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
2853 up to C<ff>. The S<<-- HERE> shows whereabouts in the regular expression the
2854 problem was discovered. See L<perlre>.
2856 =item Invalid range "%s" in transliteration operator
2858 (F) The range specified in the tr/// or y/// operator had a minimum
2859 character greater than the maximum character. See L<perlop>.
2861 =item Invalid separator character %s in attribute list
2863 (F) Something other than a colon or whitespace was seen between the
2864 elements of an attribute list. If the previous attribute had a
2865 parenthesised parameter list, perhaps that list was terminated too soon.
2868 =item Invalid separator character %s in PerlIO layer specification %s
2870 (W layer) When pushing layers onto the Perl I/O system, something other
2871 than a colon or whitespace was seen between the elements of a layer list.
2872 If the previous attribute had a parenthesised parameter list, perhaps that
2873 list was terminated too soon.
2875 =item Invalid strict version format (%s)
2877 (F) A version number did not meet the "strict" criteria for versions.
2878 A "strict" version number is a positive decimal number (integer or
2879 decimal-fraction) without exponentiation or else a dotted-decimal
2880 v-string with a leading 'v' character and at least three components.
2881 The parenthesized text indicates which criteria were not met.
2882 See the L<version> module for more details on allowed version formats.
2884 =item Invalid type '%s' in %s
2886 (F) The given character is not a valid pack or unpack type.
2887 See L<perlfunc/pack>.
2889 (W) The given character is not a valid pack or unpack type but used to be
2892 =item Invalid version format (%s)
2894 (F) A version number did not meet the "lax" criteria for versions.
2895 A "lax" version number is a positive decimal number (integer or
2896 decimal-fraction) without exponentiation or else a dotted-decimal
2897 v-string. If the v-string has fewer than three components, it
2898 must have a leading 'v' character. Otherwise, the leading 'v' is
2899 optional. Both decimal and dotted-decimal versions may have a
2900 trailing "alpha" component separated by an underscore character
2901 after a fractional or dotted-decimal component. The parenthesized
2902 text indicates which criteria were not met. See the L<version> module
2903 for more details on allowed version formats.
2905 =item Invalid version object
2907 (F) The internal structure of the version object was invalid.
2908 Perhaps the internals were modified directly in some way or
2909 an arbitrary reference was blessed into the "version" class.
2911 =item In '(*VERB...)', the '(' and '*' must be adjacent in regex;
2912 marked by S<<-- HERE> in m/%s/
2914 (F) The two-character sequence C<"(*"> in
2915 this context in a regular expression pattern should be an
2916 indivisible token, with nothing intervening between the C<"(">
2917 and the C<"*">, but you separated them.
2919 =item ioctl is not implemented
2921 (F) Your machine apparently doesn't implement ioctl(), which is pretty
2922 strange for a machine that supports C.
2924 =item ioctl() on unopened %s
2926 (W unopened) You tried ioctl() on a filehandle that was never opened.
2927 Check your control flow and number of arguments.
2929 =item IO layers (like '%s') unavailable
2931 (F) Your Perl has not been configured to have PerlIO, and therefore
2932 you cannot use IO layers. To have PerlIO, Perl must be configured
2935 =item IO::Socket::atmark not implemented on this architecture
2937 (F) Your machine doesn't implement the sockatmark() functionality,
2938 neither as a system call nor an ioctl call (SIOCATMARK).
2940 =item '%s' is an unknown bound type in regex; marked by S<<-- HERE> in m/%s/
2942 (F) You used C<\b{...}> or C<\B{...}> and the C<...> is not known to
2943 Perl. The current valid ones are given in
2944 L<perlrebackslash/\b{}, \b, \B{}, \B>.
2946 =item "%s" is more clearly written simply as "%s" in regex; marked by S<<-- HERE> in m/%s/
2948 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
2950 You specified a character that has the given plainer way of writing it,
2951 and which is also portable to platforms running with different character
2954 =item $* is no longer supported
2956 (D deprecated, syntax) The special variable C<$*>, deprecated in older
2957 perls, has been removed as of 5.10.0 and is no longer supported. In
2958 previous versions of perl the use of C<$*> enabled or disabled multi-line
2959 matching within a string.
2961 Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
2962 modifiers. You can enable C</m> for a lexical scope (even a whole file)
2963 with C<use re '/m'>. (In older versions: when C<$*> was set to a true value
2964 then all regular expressions behaved as if they were written using C</m>.)
2966 =item $# is no longer supported
2968 (D deprecated, syntax) The special variable C<$#>, deprecated in older
2969 perls, has been removed as of 5.10.0 and is no longer supported. You
2970 should use the printf/sprintf functions instead.
2972 =item '%s' is not a code reference
2974 (W overload) The second (fourth, sixth, ...) argument of
2975 overload::constant needs to be a code reference. Either
2976 an anonymous subroutine, or a reference to a subroutine.
2978 =item '%s' is not an overloadable type
2980 (W overload) You tried to overload a constant type the overload package is
2983 =item -i used with no filenames on the command line, reading from STDIN
2985 (S inplace) The C<-i> option was passed on the command line, indicating
2986 that the script is intended to edit files in place, but no files were
2987 given. This is usually a mistake, since editing STDIN in place doesn't
2988 make sense, and can be confusing because it can make perl look like
2989 it is hanging when it is really just trying to read from STDIN. You
2990 should either pass a filename to edit, or remove C<-i> from the command
2991 line. See L<perlrun> for more details.
2993 =item Junk on end of regexp in regex m/%s/
2995 (P) The regular expression parser is confused.
2997 =item Label not found for "last %s"
2999 (F) You named a loop to break out of, but you're not currently in a loop
3000 of that name, not even if you count where you were called from. See
3003 =item Label not found for "next %s"
3005 (F) You named a loop to continue, but you're not currently in a loop of
3006 that name, not even if you count where you were called from. See
3009 =item Label not found for "redo %s"
3011 (F) You named a loop to restart, but you're not currently in a loop of
3012 that name, not even if you count where you were called from. See
3015 =item leaving effective %s failed
3017 (F) While under the C<use filetest> pragma, switching the real and
3018 effective uids or gids failed.
3020 =item length/code after end of string in unpack
3022 (F) While unpacking, the string buffer was already used up when an unpack
3023 length/code combination tried to obtain more data. This results in
3024 an undefined value for the length. See L<perlfunc/pack>.
3026 =item length() used on %s (did you mean "scalar(%s)"?)
3028 (W syntax) You used length() on either an array or a hash when you
3029 probably wanted a count of the items.
3031 Array size can be obtained by doing:
3035 The number of items in a hash can be obtained by doing:
3039 =item Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
3041 (F) An extension is attempting to insert text into the current parse
3042 (using L<lex_stuff_pvn|perlapi/lex_stuff_pvn> or similar), but tried to insert a character that
3043 couldn't be part of the current input. This is an inherent pitfall
3044 of the stuffing mechanism, and one of the reasons to avoid it. Where
3045 it is necessary to stuff, stuffing only plain ASCII is recommended.
3047 =item Lexing code internal error (%s)
3049 (F) Lexing code supplied by an extension violated the lexer's API in a
3052 =item listen() on closed socket %s
3054 (W closed) You tried to do a listen on a closed socket. Did you forget
3055 to check the return value of your socket() call? See
3058 =item List form of piped open not implemented
3060 (F) On some platforms, notably Windows, the three-or-more-arguments
3061 form of C<open> does not support pipes, such as C<open($pipe, '|-', @args)>.
3062 Use the two-argument C<open($pipe, '|prog arg1 arg2...')> form instead.
3064 =item %s: loadable library and perl binaries are mismatched (got handshake key %p, needed %p)
3066 (P) A dynamic loading library C<.so> or C<.dll> was being loaded into the
3067 process that was built against a different build of perl than the
3068 said library was compiled against. Reinstalling the XS module will
3069 likely fix this error.
3071 =item Locale '%s' may not work well.%s
3073 (W locale) You are using the named locale, which is a non-UTF-8 one, and
3074 which perl has determined is not fully compatible with what it can
3075 handle. The second C<%s> gives a reason.
3077 By far the most common reason is that the locale has characters in it
3078 that are represented by more than one byte. The only such locales that
3079 Perl can handle are the UTF-8 locales. Most likely the specified locale
3080 is a non-UTF-8 one for an East Asian language such as Chinese or
3081 Japanese. If the locale is a superset of ASCII, the ASCII portion of it
3084 Some essentially obsolete locales that aren't supersets of ASCII, mainly
3085 those in ISO 646 or other 7-bit locales, such as ASMO 449, can also have
3086 problems, depending on what portions of the ASCII character set get
3087 changed by the locale and are also used by the program.
3088 The warning message lists the determinable conflicting characters.
3090 Note that not all incompatibilities are found.
3092 If this happens to you, there's not much you can do except switch to use a
3093 different locale or use L<Encode> to translate from the locale into
3094 UTF-8; if that's impracticable, you have been warned that some things
3097 This message is output once each time a bad locale is switched into
3098 within the scope of C<S<use locale>>, or on the first possibly-affected
3099 operation if the C<S<use locale>> inherits a bad one. It is not raised
3100 for any operations from the L<POSIX> module.
3102 =item localtime(%f) failed
3104 (W overflow) You called C<localtime> with a number that it could not handle:
3105 too large, too small, or NaN. The returned value is C<undef>.
3107 =item localtime(%f) too large
3109 (W overflow) You called C<localtime> with a number that was larger
3110 than it can reliably handle and C<localtime> probably returned the
3111 wrong date. This warning is also triggered with NaN (the special
3112 not-a-number value).
3114 =item localtime(%f) too small
3116 (W overflow) You called C<localtime> with a number that was smaller
3117 than it can reliably handle and C<localtime> probably returned the
3120 =item Lookbehind longer than %d not implemented in regex m/%s/
3122 (F) There is currently a limit on the length of string which lookbehind can
3123 handle. This restriction may be eased in a future release.
3125 =item Lost precision when %s %f by 1
3127 (W imprecision) The value you attempted to increment or decrement by one
3128 is too large for the underlying floating point representation to store
3129 accurately, hence the target of C<++> or C<--> is unchanged. Perl issues this
3130 warning because it has already switched from integers to floating point
3131 when values are too large for integers, and now even floating point is
3132 insufficient. You may wish to switch to using L<Math::BigInt> explicitly.
3134 =item lstat() on filehandle%s
3136 (W io) You tried to do an lstat on a filehandle. What did you mean
3137 by that? lstat() makes sense only on filenames. (Perl did a fstat()
3138 instead on the filehandle.)
3140 =item lvalue attribute %s already-defined subroutine
3142 (W misc) Although L<attributes.pm|attributes> allows this, turning the lvalue
3143 attribute on or off on a Perl subroutine that is already defined
3144 does not always work properly. It may or may not do what you
3145 want, depending on what code is inside the subroutine, with exact
3146 details subject to change between Perl versions. Only do this
3147 if you really know what you are doing.
3149 =item lvalue attribute ignored after the subroutine has been defined
3151 (W misc) Using the C<:lvalue> declarative syntax to make a Perl
3152 subroutine an lvalue subroutine after it has been defined is
3153 not permitted. To make the subroutine an lvalue subroutine,
3154 add the lvalue attribute to the definition, or put the C<sub
3155 foo :lvalue;> declaration before the definition.
3157 See also L<attributes.pm|attributes>.
3159 =item Magical list constants are not supported
3161 (F) You assigned a magical array to a stash element, and then tried
3162 to use the subroutine from the same slot. You are asking Perl to do
3163 something it cannot do, details subject to change between Perl versions.
3165 =item Malformed integer in [] in pack
3167 (F) Between the brackets enclosing a numeric repeat count only digits
3168 are permitted. See L<perlfunc/pack>.
3170 =item Malformed integer in [] in unpack
3172 (F) Between the brackets enclosing a numeric repeat count only digits
3173 are permitted. See L<perlfunc/pack>.
3175 =item Malformed PERLLIB_PREFIX
3177 (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
3184 with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
3185 a builtin library search path, prefix2 is substituted. The error may
3186 appear if components are not found, or are too long. See
3187 "PERLLIB_PREFIX" in L<perlos2>.
3189 =item Malformed prototype for %s: %s
3191 (F) You tried to use a function with a malformed prototype. The
3192 syntax of function prototypes is given a brief compile-time check for
3193 obvious errors like invalid characters. A more rigorous check is run
3194 when the function is called.
3195 Perhaps the function's author was trying to write a subroutine signature
3196 but didn't enable that feature first (C<use feature 'signatures'>),
3197 so the signature was instead interpreted as a bad prototype.
3199 =item Malformed UTF-8 character (%s)
3201 (S utf8)(F) Perl detected a string that didn't comply with UTF-8
3202 encoding rules, even though it had the UTF8 flag on.
3204 One possible cause is that you set the UTF8 flag yourself for data that
3205 you thought to be in UTF-8 but it wasn't (it was for example legacy
3206 8-bit data). To guard against this, you can use Encode::decode_utf8.
3208 If you use the C<:encoding(UTF-8)> PerlIO layer for input, invalid byte
3209 sequences are handled gracefully, but if you use C<:utf8>, the flag is
3210 set without validating the data, possibly resulting in this error
3213 See also L<Encode/"Handling Malformed Data">.
3215 =item Malformed UTF-8 character immediately after '%s'
3217 (F) You said C<use utf8>, but the program file doesn't comply with UTF-8
3218 encoding rules. The message prints out the properly encoded characters
3219 just before the first bad one. If C<utf8> warnings are enabled, a
3220 warning is generated that gives more details about the type of
3223 =item Malformed UTF-8 returned by \N{%s} immediately after '%s'
3225 (F) The charnames handler returned malformed UTF-8.
3227 =item Malformed UTF-8 string in '%c' format in unpack
3229 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3230 rules and perl was unable to guess how to make more progress.
3232 =item Malformed UTF-8 string in pack
3234 (F) You tried to pack something that didn't comply with UTF-8 encoding
3235 rules and perl was unable to guess how to make more progress.
3237 =item Malformed UTF-8 string in unpack
3239 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3240 rules and perl was unable to guess how to make more progress.
3242 =item Malformed UTF-16 surrogate
3244 (F) Perl thought it was reading UTF-16 encoded character data but while
3245 doing it Perl met a malformed Unicode surrogate.
3247 =item Mandatory parameter follows optional parameter
3249 (F) In a subroutine signature, you wrote something like "$a = undef,
3250 $b", making an earlier parameter optional and a later one mandatory.
3251 Parameters are filled from left to right, so it's impossible for the
3252 caller to omit an earlier one and pass a later one. If you want to act
3253 as if the parameters are filled from right to left, declare the rightmost
3254 optional and then shuffle the parameters around in the subroutine's body.
3256 =item Matched non-Unicode code point 0x%X against Unicode property; may
3259 (S non_unicode) Perl allows strings to contain a superset of
3260 Unicode code points; each code point may be as large as what is storable
3261 in an unsigned integer on your system, but these may not be accepted by
3262 other languages/systems. This message occurs when you matched a string
3263 containing such a code point against a regular expression pattern, and
3264 the code point was matched against a Unicode property, C<\p{...}> or
3265 C<\P{...}>. Unicode properties are only defined on Unicode code points,
3266 so the result of this match is undefined by Unicode, but Perl (starting
3267 in v5.20) treats non-Unicode code points as if they were typical
3268 unassigned Unicode ones, and matched this one accordingly. Whether a
3269 given property matches these code points or not is specified in
3270 L<perluniprops/Properties accessible through \p{} and \P{}>.
3272 This message is suppressed (unless it has been made fatal) if it is
3273 immaterial to the results of the match if the code point is Unicode or
3274 not. For example, the property C<\p{ASCII_Hex_Digit}> only can match
3275 the 22 characters C<[0-9A-Fa-f]>, so obviously all other code points,
3276 Unicode or not, won't match it. (And C<\P{ASCII_Hex_Digit}> will match
3277 every code point except these 22.)
3279 Getting this message indicates that the outcome of the match arguably
3280 should have been the opposite of what actually happened. If you think
3281 that is the case, you may wish to make the C<non_unicode> warnings
3282 category fatal; if you agree with Perl's decision, you may wish to turn
3285 See L<perlunicode/Beyond Unicode code points> for more information.
3287 =item %s matches null string many times in regex; marked by S<<-- HERE> in
3290 (W regexp) The pattern you've specified would be an infinite loop if the
3291 regular expression engine didn't specifically check for that. The S<<-- HERE>
3292 shows whereabouts in the regular expression the problem was discovered.
3295 =item Maximal count of pending signals (%u) exceeded
3297 (F) Perl aborted due to too high a number of signals pending. This
3298 usually indicates that your operating system tried to deliver signals
3299 too fast (with a very high priority), starving the perl process from
3300 resources it would need to reach a point where it can process signals
3301 safely. (See L<perlipc/"Deferred Signals (Safe Signals)">.)
3303 =item "%s" may clash with future reserved word
3305 (W) This warning may be due to running a perl5 script through a perl4
3306 interpreter, especially if the word that is being warned about is
3309 =item '%' may not be used in pack
3311 (F) You can't pack a string by supplying a checksum, because the
3312 checksumming process loses information, and you can't go the other way.
3313 See L<perlfunc/unpack>.
3315 =item Method for operation %s not found in package %s during blessing
3317 (F) An attempt was made to specify an entry in an overloading table that
3318 doesn't resolve to a valid subroutine. See L<overload>.
3320 =item Method %s not permitted
3324 =item Might be a runaway multi-line %s string starting on line %d
3326 (S) An advisory indicating that the previous error may have been caused
3327 by a missing delimiter on a string or pattern, because it eventually
3328 ended earlier on the current line.
3330 =item Misplaced _ in number
3332 (W syntax) An underscore (underbar) in a numeric constant did not
3333 separate two digits.
3335 =item Missing argument in %s
3337 (W missing) You called a function with fewer arguments than other
3338 arguments you supplied indicated would be needed.
3340 Currently only emitted when a printf-type format required more
3341 arguments than were supplied, but might be used in the future for
3342 other cases where we can statically determine that arguments to
3343 functions are missing, e.g. for the L<perlfunc/pack> function.
3345 =item Missing argument to -%c
3347 (F) The argument to the indicated command line switch must follow
3348 immediately after the switch, without intervening spaces.
3350 =item Missing braces on \N{}
3352 =item Missing braces on \N{} in regex; marked by S<<-- HERE> in m/%s/
3354 (F) Wrong syntax of character name literal C<\N{charname}> within
3355 double-quotish context. This can also happen when there is a space
3356 (or comment) between the C<\N> and the C<{> in a regex with the C</x> modifier.
3357 This modifier does not change the requirement that the brace immediately
3360 =item Missing braces on \o{}
3362 (F) A C<\o> must be followed immediately by a C<{> in double-quotish context.
3364 =item Missing comma after first argument to %s function
3366 (F) While certain functions allow you to specify a filehandle or an
3367 "indirect object" before the argument list, this ain't one of them.
3369 =item Missing command in piped open
3371 (W pipe) You used the C<open(FH, "| command")> or
3372 C<open(FH, "command |")> construction, but the command was missing or
3375 =item Missing control char name in \c
3377 (F) A double-quoted string ended with "\c", without the required control
3380 =item Missing ']' in prototype for %s : %s
3382 (W illegalproto) A grouping was started with C<[> but never closed with C<]>.
3384 =item Missing name in "%s sub"
3386 (F) The syntax for lexically scoped subroutines requires that
3387 they have a name with which they can be found.
3389 =item Missing $ on loop variable
3391 (F) Apparently you've been programming in B<csh> too much. Variables
3392 are always mentioned with the $ in Perl, unlike in the shells, where it
3393 can vary from one line to the next.
3395 =item (Missing operator before %s?)
3397 (S syntax) This is an educated guess made in conjunction with the message
3398 "%s found where operator expected". Often the missing operator is a comma.
3400 =item Missing or undefined argument to require
3402 (F) You tried to call require with no argument or with an undefined
3403 value as an argument. Require expects either a package name or a
3404 file-specification as an argument. See L<perlfunc/require>.
3406 =item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
3408 (F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
3410 =item Missing right brace on \N{}
3412 =item Missing right brace on \N{} or unescaped left brace after \N
3414 (F) C<\N> has two meanings.
3416 The traditional one has it followed by a name enclosed in braces,
3417 meaning the character (or sequence of characters) given by that
3418 name. Thus C<\N{ASTERISK}> is another way of writing C<*>, valid in both
3419 double-quoted strings and regular expression patterns. In patterns,
3420 it doesn't have the meaning an unescaped C<*> does.
3422 Starting in Perl 5.12.0, C<\N> also can have an additional meaning (only)
3423 in patterns, namely to match a non-newline character. (This is short
3424 for C<[^\n]>, and like C<.> but is not affected by the C</s> regex modifier.)
3426 This can lead to some ambiguities. When C<\N> is not followed immediately
3427 by a left brace, Perl assumes the C<[^\n]> meaning. Also, if the braces
3428 form a valid quantifier such as C<\N{3}> or C<\N{5,}>, Perl assumes that this
3429 means to match the given quantity of non-newlines (in these examples,
3430 3; and 5 or more, respectively). In all other case, where there is a
3431 C<\N{> and a matching C<}>, Perl assumes that a character name is desired.
3433 However, if there is no matching C<}>, Perl doesn't know if it was
3434 mistakenly omitted, or if C<[^\n]{> was desired, and raises this error.
3435 If you meant the former, add the right brace; if you meant the latter,
3436 escape the brace with a backslash, like so: C<\N\{>
3438 =item Missing right curly or square bracket
3440 (F) The lexer counted more opening curly or square brackets than closing
3441 ones. As a general rule, you'll find it's missing near the place you
3444 =item (Missing semicolon on previous line?)
3446 (S syntax) This is an educated guess made in conjunction with the message
3447 "%s found where operator expected". Don't automatically put a semicolon on
3448 the previous line just because you saw this message.
3450 =item Modification of a read-only value attempted
3452 (F) You tried, directly or indirectly, to change the value of a
3453 constant. You didn't, of course, try "2 = 1", because the compiler
3454 catches that. But an easy way to do the same thing is:
3456 sub mod { $_[0] = 1 }
3459 Another way is to assign to a substr() that's off the end of the string.
3461 Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
3462 is aliased to a constant in the look I<LIST>:
3465 foreach my $n ($x, 2) {
3466 $n *= 2; # modifies the $x, but fails on attempt to
3469 =item Modification of non-creatable array value attempted, %s
3471 (F) You tried to make an array value spring into existence, and the
3472 subscript was probably negative, even counting from end of the array
3475 =item Modification of non-creatable hash value attempted, %s
3477 (P) You tried to make a hash value spring into existence, and it
3478 couldn't be created for some peculiar reason.
3480 =item Module name must be constant
3482 (F) Only a bare module name is allowed as the first argument to a "use".
3484 =item Module name required with -%c option
3486 (F) The C<-M> or C<-m> options say that Perl should load some module, but
3487 you omitted the name of the module. Consult L<perlrun> for full details
3488 about C<-M> and C<-m>.
3490 =item More than one argument to '%s' open
3492 (F) The C<open> function has been asked to open multiple files. This
3493 can happen if you are trying to open a pipe to a command that takes a
3494 list of arguments, but have forgotten to specify a piped open mode.
3495 See L<perlfunc/open> for details.
3497 =item mprotect for COW string %p %u failed with %d
3499 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3500 L<perlguts/"Copy on Write">), but a shared string buffer
3501 could not be made read-only.
3503 =item mprotect for %p %u failed with %d
3505 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see L<perlhacktips>),
3506 but an op tree could not be made read-only.
3508 =item mprotect RW for COW string %p %u failed with %d
3510 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3511 L<perlguts/"Copy on Write">), but a read-only shared string
3512 buffer could not be made mutable.
3514 =item mprotect RW for %p %u failed with %d
3516 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see
3517 L<perlhacktips>), but a read-only op tree could not be made
3518 mutable before freeing the ops.
3520 =item msg%s not implemented
3522 (F) You don't have System V message IPC on your system.
3524 =item Multidimensional syntax %s not supported
3526 (W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
3527 They're written like C<$foo[1][2][3]>, as in C.
3529 =item '/' must follow a numeric type in unpack
3531 (F) You had an unpack template that contained a '/', but this did not
3532 follow some unpack specification producing a numeric value.
3533 See L<perlfunc/pack>.
3535 =item %s must not be a named sequence in transliteration operator
3537 (F) Transliteration (C<tr///> and C<y///>) transliterates individual
3538 characters. But a named sequence by definition is more than an
3539 individual charater, and hence doing this operation on it doesn't make
3542 =item "my sub" not yet implemented
3544 (F) Lexically scoped subroutines are not yet implemented. Don't try
3547 =item "my" subroutine %s can't be in a package
3549 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
3550 sense to try to declare one with a package qualifier on the front.
3552 =item "my %s" used in sort comparison
3554 (W syntax) The package variables $a and $b are used for sort comparisons.
3555 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
3556 sort comparison block, and the variable had earlier been declared as a
3557 lexical variable. Either qualify the sort variable with the package
3558 name, or rename the lexical variable.
3560 =item "my" variable %s can't be in a package
3562 (F) Lexically scoped variables aren't in a package, so it doesn't make
3563 sense to try to declare one with a package qualifier on the front. Use
3564 local() if you want to localize a package variable.
3566 =item Name "%s::%s" used only once: possible typo
3568 (W once) Typographical errors often show up as unique variable
3569 names. If you had a good reason for having a unique name, then
3570 just mention it again somehow to suppress the message. The C<our>
3571 declaration is also provided for this purpose.
3573 NOTE: This warning detects package symbols that have been used
3574 only once. This means lexical variables will never trigger this
3575 warning. It also means that all of the package variables $c, @c,
3576 %c, as well as *c, &c, sub c{}, c(), and c (the filehandle or
3577 format) are considered the same; if a program uses $c only once
3578 but also uses any of the others it will not trigger this warning.
3579 Symbols beginning with an underscore and symbols using special
3580 identifiers (q.v. L<perldata>) are exempt from this warning.
3582 =item Need exactly 3 octal digits in regex; marked by S<<-- HERE> in m/%s/
3584 (F) Within S<C<(?[ ])>>, all constants interpreted as octal need to be
3585 exactly 3 digits long. This helps catch some ambiguities. If your
3586 constant is too short, add leading zeros, like
3588 (?[ [ \078 ] ]) # Syntax error!
3589 (?[ [ \0078 ] ]) # Works
3590 (?[ [ \007 8 ] ]) # Clearer
3592 The maximum number this construct can express is C<\777>. If you
3593 need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes> instead. If you meant
3594 two separate things, you need to separate them:
3596 (?[ [ \7776 ] ]) # Syntax error!
3597 (?[ [ \o{7776} ] ]) # One meaning
3598 (?[ [ \777 6 ] ]) # Another meaning
3599 (?[ [ \777 \006 ] ]) # Still another
3601 =item Negative '/' count in unpack
3603 (F) The length count obtained from a length/code unpack operation was
3604 negative. See L<perlfunc/pack>.
3606 =item Negative length
3608 (F) You tried to do a read/write/send/recv operation with a buffer
3609 length that is less than 0. This is difficult to imagine.
3611 =item Negative offset to vec in lvalue context
3613 (F) When C<vec> is called in an lvalue context, the second argument must be
3614 greater than or equal to zero.
3616 =item Negative repeat count does nothing
3618 (W numeric) You tried to execute the
3619 L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
3620 times, which doesn't make sense.
3622 =item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
3624 (F) You can't quantify a quantifier without intervening parentheses.
3625 So things like ** or +* or ?* are illegal. The S<<-- HERE> shows
3626 whereabouts in the regular expression the problem was discovered.
3628 Note that the minimal matching quantifiers, C<*?>, C<+?>, and
3629 C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
3631 =item %s never introduced
3633 (S internal) The symbol in question was declared but somehow went out of
3634 scope before it could possibly have been used.
3636 =item next::method/next::can/maybe::next::method cannot find enclosing method
3638 (F) C<next::method> needs to be called within the context of a
3639 real method in a real package, and it could not find such a context.
3642 =item \N in a character class must be a named character: \N{...} in regex;
3643 marked by S<<-- HERE> in m/%s/
3645 (F) The new (as of Perl 5.12) meaning of C<\N> as C<[^\n]> is not valid in a
3646 bracketed character class, for the same reason that C<.> in a character
3647 class loses its specialness: it matches almost everything, which is
3648 probably not what you want.
3650 =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/
3652 (F) Named Unicode character escapes (C<\N{...}>) may return a
3653 multi-character sequence. Even though a character class is
3654 supposed to match just one character of input, perl will match the
3655 whole thing correctly, except when the class is inverted (C<[^...]>),
3656 or the escape is the beginning or final end point of a range. The
3657 mathematically logical behavior for what matches when inverting
3658 is very different from what people expect, so we have decided to
3659 forbid it. Similarly unclear is what should be generated when the
3660 C<\N{...}> is used as one of the end points of the range, such as in
3662 [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]
3664 What is meant here is unclear, as the C<\N{...}> escape is a sequence
3665 of code points, so this is made an error.
3667 =item \N{NAME} must be resolved by the lexer in regex; marked by
3668 S<<-- HERE> in m/%s/
3670 (F) When compiling a regex pattern, an unresolved named character or
3671 sequence was encountered. This can happen in any of several ways that
3672 bypass the lexer, such as using single-quotish context, or an extra
3673 backslash in double-quotish:
3675 $re = '\N{SPACE}'; # Wrong!
3676 $re = "\\N{SPACE}"; # Wrong!
3679 Instead, use double-quotes with a single backslash:
3681 $re = "\N{SPACE}"; # ok
3684 The lexer can be bypassed as well by creating the pattern from smaller
3688 /${re}{SPACE}/; # Wrong!
3690 It's not a good idea to split a construct in the middle like this, and
3691 it doesn't work here. Instead use the solution above.
3693 Finally, the message also can happen under the C</x> regex modifier when the
3694 C<\N> is separated by spaces from the C<{>, in which case, remove the spaces.
3696 /\N {SPACE}/x; # Wrong!
3699 =item No %s allowed while running setuid
3701 (F) Certain operations are deemed to be too insecure for a setuid or
3702 setgid script to even be allowed to attempt. Generally speaking there
3703 will be another way to do what you want that is, if not secure, at least
3704 securable. See L<perlsec>.
3706 =item NO-BREAK SPACE in a charnames alias definition is deprecated
3708 (D deprecated) You defined a character name which contained a no-break
3709 space character. Change it to a regular space. Usually these names are
3710 defined in the C<:alias> import argument to C<use charnames>, but they
3711 could be defined by a translator installed into C<$^H{charnames}>. See
3712 L<charnames/CUSTOM ALIASES>.
3714 =item No code specified for -%c
3716 (F) Perl's B<-e> and B<-E> command-line options require an argument. If
3717 you want to run an empty program, pass the empty string as a separate
3718 argument or run a program consisting of a single 0 or 1:
3724 =item No comma allowed after %s
3726 (F) A list operator that has a filehandle or "indirect object" is
3727 not allowed to have a comma between that and the following arguments.
3728 Otherwise it'd be just another one of the arguments.
3730 One possible cause for this is that you expected to have imported
3731 a constant to your name space with B<use> or B<import> while no such
3732 importing took place, it may for example be that your operating
3733 system does not support that particular constant. Hopefully you did
3734 use an explicit import list for the constants you expect to see;
3735 please see L<perlfunc/use> and L<perlfunc/import>. While an
3736 explicit import list would probably have caught this error earlier
3737 it naturally does not remedy the fact that your operating system
3738 still does not support that constant. Maybe you have a typo in
3739 the constants of the symbol import list of B<use> or B<import> or in the
3740 constant name at the line where this error was triggered?
3742 =item No command into which to pipe on command line
3744 (F) An error peculiar to VMS. Perl handles its own command line
3745 redirection, and found a '|' at the end of the command line, so it
3746 doesn't know where you want to pipe the output from this command.
3748 =item No DB::DB routine defined
3750 (F) The currently executing code was compiled with the B<-d> switch, but
3751 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3752 module) didn't define a routine to be called at the beginning of each
3755 =item No dbm on this machine
3757 (P) This is counted as an internal error, because every machine should
3758 supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
3760 =item No DB::sub routine defined
3762 (F) The currently executing code was compiled with the B<-d> switch, but
3763 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3764 module) didn't define a C<DB::sub> routine to be called at the beginning
3765 of each ordinary subroutine call.
3767 =item No directory specified for -I
3769 (F) The B<-I> command-line switch requires a directory name as part of the
3770 I<same> argument. Use B<-Ilib>, for instance. B<-I lib> won't work.
3772 =item No error file after 2> or 2>> on command line
3774 (F) An error peculiar to VMS. Perl handles its own command line
3775 redirection, and found a '2>' or a '2>>' on the command line, but can't
3776 find the name of the file to which to write data destined for stderr.
3778 =item No group ending character '%c' found in template
3780 (F) A pack or unpack template has an opening '(' or '[' without its
3781 matching counterpart. See L<perlfunc/pack>.
3783 =item No input file after < on command line
3785 (F) An error peculiar to VMS. Perl handles its own command line
3786 redirection, and found a '<' on the command line, but can't find the
3787 name of the file from which to read data for stdin.
3789 =item No next::method '%s' found for %s
3791 (F) C<next::method> found no further instances of this method name
3792 in the remaining packages of the MRO of this class. If you don't want
3793 it throwing an exception, use C<maybe::next::method>
3794 or C<next::can>. See L<mro>.
3796 =item Non-finite repeat count does nothing
3798 (W numeric) You tried to execute the
3799 L<C<x>|perlop/Multiplicative Operators> repetition operator C<Inf> (or
3800 C<-Inf>) or C<NaN> times, which doesn't make sense.
3802 =item Non-hex character in regex; marked by S<<-- HERE> in m/%s/
3804 (F) In a regular expression, there was a non-hexadecimal character where
3805 a hex one was expected, like
3810 =item Non-octal character in regex; marked by S<<-- HERE> in m/%s/
3812 (F) In a regular expression, there was a non-octal character where
3813 an octal one was expected, like
3817 =item Non-octal character '%c'. Resolved as "%s"
3819 (W digit) In parsing an octal numeric constant, a character was
3820 unexpectedly encountered that isn't octal. The resulting value
3823 =item "no" not allowed in expression
3825 (F) The "no" keyword is recognized and executed at compile time, and
3826 returns no useful value. See L<perlmod>.
3828 =item Non-string passed as bitmask
3830 (W misc) A number has been passed as a bitmask argument to select().
3831 Use the vec() function to construct the file descriptor bitmasks for
3832 select. See L<perlfunc/select>.
3834 =item No output file after > on command line
3836 (F) An error peculiar to VMS. Perl handles its own command line
3837 redirection, and found a lone '>' at the end of the command line, so it
3838 doesn't know where you wanted to redirect stdout.
3840 =item No output file after > or >> on command line
3842 (F) An error peculiar to VMS. Perl handles its own command line
3843 redirection, and found a '>' or a '>>' on the command line, but can't
3844 find the name of the file to which to write data destined for stdout.
3846 =item No package name allowed for variable %s in "our"
3848 (F) Fully qualified variable names are not allowed in "our"
3849 declarations, because that doesn't make much sense under existing
3850 rules. Such syntax is reserved for future extensions.
3852 =item No Perl script found in input
3854 (F) You called C<perl -x>, but no line was found in the file beginning
3855 with #! and containing the word "perl".
3857 =item No setregid available
3859 (F) Configure didn't find anything resembling the setregid() call for
3862 =item No setreuid available
3864 (F) Configure didn't find anything resembling the setreuid() call for
3867 =item No such class %s
3869 (F) You provided a class qualifier in a "my", "our" or "state"
3870 declaration, but this class doesn't exist at this point in your program.
3872 =item No such class field "%s" in variable %s of type %s
3874 (F) You tried to access a key from a hash through the indicated typed
3875 variable but that key is not allowed by the package of the same type.
3876 The indicated package has restricted the set of allowed keys using the
3879 =item No such hook: %s
3881 (F) You specified a signal hook that was not recognized by Perl.
3882 Currently, Perl accepts C<__DIE__> and C<__WARN__> as valid signal hooks.
3884 =item No such pipe open
3886 (P) An error peculiar to VMS. The internal routine my_pclose() tried to
3887 close a pipe which hadn't been opened. This should have been caught
3888 earlier as an attempt to close an unopened filehandle.
3890 =item No such signal: SIG%s
3892 (W signal) You specified a signal name as a subscript to %SIG that was
3893 not recognized. Say C<kill -l> in your shell to see the valid signal
3894 names on your system.
3896 =item Not a CODE reference
3898 (F) Perl was trying to evaluate a reference to a code value (that is, a
3899 subroutine), but found a reference to something else instead. You can
3900 use the ref() function to find out what kind of ref it really was. See
3903 =item Not a GLOB reference
3905 (F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
3906 symbol table entry that looks like C<*foo>), but found a reference to
3907 something else instead. You can use the ref() function to find out what
3908 kind of ref it really was. See L<perlref>.
3910 =item Not a HASH reference
3912 (F) Perl was trying to evaluate a reference to a hash value, but found a
3913 reference to something else instead. You can use the ref() function to
3914 find out what kind of ref it really was. See L<perlref>.
3916 =item Not an ARRAY reference
3918 (F) Perl was trying to evaluate a reference to an array value, but found
3919 a reference to something else instead. You can use the ref() function
3920 to find out what kind of ref it really was. See L<perlref>.
3922 =item Not an unblessed ARRAY reference
3924 (F) You passed a reference to a blessed array to C<push>, C<shift> or
3925 another array function. These only accept unblessed array references
3926 or arrays beginning explicitly with C<@>.
3928 =item Not a SCALAR reference
3930 (F) Perl was trying to evaluate a reference to a scalar value, but found
3931 a reference to something else instead. You can use the ref() function
3932 to find out what kind of ref it really was. See L<perlref>.
3934 =item Not a subroutine reference
3936 (F) Perl was trying to evaluate a reference to a code value (that is, a
3937 subroutine), but found a reference to something else instead. You can
3938 use the ref() function to find out what kind of ref it really was. See
3941 =item Not a subroutine reference in overload table
3943 (F) An attempt was made to specify an entry in an overloading table that
3944 doesn't somehow point to a valid subroutine. See L<overload>.
3946 =item Not enough arguments for %s
3948 (F) The function requires more arguments than you specified.
3950 =item Not enough format arguments
3952 (W syntax) A format specified more picture fields than the next line
3953 supplied. See L<perlform>.
3957 (A) You've accidentally run your script through the Bourne shell instead
3958 of Perl. Check the #! line, or manually feed your script into Perl
3961 =item (?[...]) not valid in locale in regex; marked by S<<-- HERE> in m/%s/
3963 (F) C<(?[...])> cannot be used within the scope of a C<S<use locale>> or with
3964 an C</l> regular expression modifier, as that would require deferring
3965 to run-time the calculation of what it should evaluate to, and it is
3966 regex compile-time only.
3968 =item no UTC offset information; assuming local time is UTC
3970 (S) A warning peculiar to VMS. Perl was unable to find the local
3971 timezone offset, so it's assuming that local system time is equivalent
3972 to UTC. If it's not, define the logical name
3973 F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
3974 need to be added to UTC to get local time.
3976 =item NULL OP IN RUN
3978 (S debugging) Some internal routine called run() with a null opcode
3981 =item Null picture in formline
3983 (F) The first argument to formline must be a valid format picture
3984 specification. It was found to be empty, which probably means you
3985 supplied it an uninitialized value. See L<perlform>.
3989 (P) An attempt was made to realloc NULL.
3991 =item NULL regexp argument
3993 (P) The internal pattern matching routines blew it big time.
3995 =item NULL regexp parameter
3997 (P) The internal pattern matching routines are out of their gourd.
3999 =item Number too long
4001 (F) Perl limits the representation of decimal numbers in programs to
4002 about 250 characters. You've exceeded that length. Future
4003 versions of Perl are likely to eliminate this arbitrary limitation. In
4004 the meantime, try using scientific notation (e.g. "1e6" instead of
4007 =item Number with no digits
4009 (F) Perl was looking for a number but found nothing that looked like
4010 a number. This happens, for example with C<\o{}>, with no number between
4013 =item Octal number > 037777777777 non-portable
4015 (W portable) The octal number you specified is larger than 2**32-1
4016 (4294967295) and therefore non-portable between systems. See
4017 L<perlport> for more on portability concerns.
4019 =item Odd name/value argument for subroutine
4021 (F) A subroutine using a slurpy hash parameter in its signature
4022 received an odd number of arguments to populate the hash. It requires
4023 the arguments to be paired, with the same number of keys as values.
4024 The caller of the subroutine is presumably at fault. Inconveniently,
4025 this error will be reported at the location of the subroutine, not that
4028 =item Odd number of arguments for overload::constant
4030 (W overload) The call to overload::constant contained an odd number of
4031 arguments. The arguments should come in pairs.
4033 =item Odd number of elements in anonymous hash
4035 (W misc) You specified an odd number of elements to initialize a hash,
4036 which is odd, because hashes come in key/value pairs.
4038 =item Odd number of elements in hash assignment
4040 (W misc) You specified an odd number of elements to initialize a hash,
4041 which is odd, because hashes come in key/value pairs.
4043 =item Offset outside string
4045 (F)(W layer) You tried to do a read/write/send/recv/seek operation
4046 with an offset pointing outside the buffer. This is difficult to
4047 imagine. The sole exceptions to this are that zero padding will
4048 take place when going past the end of the string when either
4049 C<sysread()>ing a file, or when seeking past the end of a scalar opened
4050 for I/O (in anticipation of future reads and to imitate the behavior
4053 =item %s() on unopened %s
4055 (W unopened) An I/O operation was attempted on a filehandle that was
4056 never initialized. You need to do an open(), a sysopen(), or a socket()
4057 call, or call a constructor from the FileHandle package.
4059 =item -%s on unopened filehandle %s
4061 (W unopened) You tried to invoke a file test operator on a filehandle
4062 that isn't open. Check your control flow. See also L<perlfunc/-X>.
4066 (S internal) An internal warning that the grammar is screwed up.
4070 (S internal) An internal warning that the grammar is screwed up.
4072 =item Opening dirhandle %s also as a file
4074 (D io, deprecated) You used open() to associate a filehandle to
4075 a symbol (glob or scalar) that already holds a dirhandle.
4076 Although legal, this idiom might render your code confusing
4079 =item Opening filehandle %s also as a directory
4081 (D io, deprecated) You used opendir() to associate a dirhandle to
4082 a symbol (glob or scalar) that already holds a filehandle.
4083 Although legal, this idiom might render your code confusing
4086 =item Operand with no preceding operator in regex; marked by S<<-- HERE> in
4089 (F) You wrote something like
4091 (?[ \p{Digit} \p{Thai} ])
4093 There are two operands, but no operator giving how you want to combine
4096 =item Operation "%s": no method found, %s
4098 (F) An attempt was made to perform an overloaded operation for which no
4099 handler was defined. While some handlers can be autogenerated in terms
4100 of other handlers, there is no default handler for any operation, unless
4101 the C<fallback> overloading key is specified to be true. See L<overload>.
4103 =item Operation "%s" returns its argument for non-Unicode code point 0x%X
4105 (S non_unicode) You performed an operation requiring Unicode rules
4106 on a code point that is not in Unicode, so what it should do is not
4107 defined. Perl has chosen to have it do nothing, and warn you.
4109 If the operation shown is "ToFold", it means that case-insensitive
4110 matching in a regular expression was done on the code point.
4112 If you know what you are doing you can turn off this warning by
4113 C<no warnings 'non_unicode';>.
4115 =item Operation "%s" returns its argument for UTF-16 surrogate U+%X
4117 (S surrogate) You performed an operation requiring Unicode
4118 rules on a Unicode surrogate. Unicode frowns upon the use
4119 of surrogates for anything but storing strings in UTF-16, but
4120 rules are (reluctantly) defined for the surrogates, and
4121 they are to do nothing for this operation. Because the use of
4122 surrogates can be dangerous, Perl warns.
4124 If the operation shown is "ToFold", it means that case-insensitive
4125 matching in a regular expression was done on the code point.
4127 If you know what you are doing you can turn off this warning by
4128 C<no warnings 'surrogate';>.
4130 =item Operator or semicolon missing before %s
4132 (S ambiguous) You used a variable or subroutine call where the parser
4133 was expecting an operator. The parser has assumed you really meant to
4134 use an operator, but this is highly likely to be incorrect. For
4135 example, if you say "*foo *foo" it will be interpreted as if you said
4138 =item Optional parameter lacks default expression
4140 (F) In a subroutine signature, you wrote something like "$a =", making a
4141 named optional parameter without a default value. A nameless optional
4142 parameter is permitted to have no default value, but a named one must
4143 have a specific default. You probably want "$a = undef".
4145 =item "our" variable %s redeclared
4147 (W misc) You seem to have already declared the same global once before
4148 in the current lexical scope.
4150 =item Out of memory!
4152 (X) The malloc() function returned 0, indicating there was insufficient
4153 remaining memory (or virtual memory) to satisfy the request. Perl has
4154 no option but to exit immediately.
4156 At least in Unix you may be able to get past this by increasing your
4157 process datasize limits: in csh/tcsh use C<limit> and
4158 C<limit datasize n> (where C<n> is the number of kilobytes) to check
4159 the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
4160 and C<ulimit -d n>, respectively.
4162 =item Out of memory during %s extend
4164 (X) An attempt was made to extend an array, a list, or a string beyond
4165 the largest possible memory allocation.
4167 =item Out of memory during "large" request for %s
4169 (F) The malloc() function returned 0, indicating there was insufficient
4170 remaining memory (or virtual memory) to satisfy the request. However,
4171 the request was judged large enough (compile-time default is 64K), so a
4172 possibility to shut down by trapping this error is granted.
4174 =item Out of memory during request for %s
4176 (X)(F) The malloc() function returned 0, indicating there was
4177 insufficient remaining memory (or virtual memory) to satisfy the
4180 The request was judged to be small, so the possibility to trap it
4181 depends on the way perl was compiled. By default it is not trappable.
4182 However, if compiled for this, Perl may use the contents of C<$^M> as an
4183 emergency pool after die()ing with this message. In this case the error
4184 is trappable I<once>, and the error message will include the line and file
4185 where the failed request happened.
4187 =item Out of memory during ridiculously large request
4189 (F) You can't allocate more than 2^31+"small amount" bytes. This error
4190 is most likely to be caused by a typo in the Perl program. e.g.,
4191 C<$arr[time]> instead of C<$arr[$time]>.
4193 =item Out of memory for yacc stack
4195 (F) The yacc parser wanted to grow its stack so it could continue
4196 parsing, but realloc() wouldn't give it more memory, virtual or
4199 =item '.' outside of string in pack
4201 (F) The argument to a '.' in your template tried to move the working
4202 position to before the start of the packed string being built.
4204 =item '@' outside of string in unpack
4206 (F) You had a template that specified an absolute position outside
4207 the string being unpacked. See L<perlfunc/pack>.
4209 =item '@' outside of string with malformed UTF-8 in unpack
4211 (F) You had a template that specified an absolute position outside
4212 the string being unpacked. The string being unpacked was also invalid
4213 UTF-8. See L<perlfunc/pack>.
4215 =item overload arg '%s' is invalid
4217 (W overload) The L<overload> pragma was passed an argument it did not
4218 recognize. Did you mistype an operator?
4220 =item Overloaded dereference did not return a reference
4222 (F) An object with an overloaded dereference operator was dereferenced,
4223 but the overloaded operation did not return a reference. See
4226 =item Overloaded qr did not return a REGEXP
4228 (F) An object with a C<qr> overload was used as part of a match, but the
4229 overloaded operation didn't return a compiled regexp. See L<overload>.
4231 =item %s package attribute may clash with future reserved word: %s
4233 (W reserved) A lowercase attribute name was used that had a
4234 package-specific handler. That name might have a meaning to Perl itself
4235 some day, even though it doesn't yet. Perhaps you should use a
4236 mixed-case attribute name, instead. See L<attributes>.
4238 =item pack/unpack repeat count overflow
4240 (F) You can't specify a repeat count so large that it overflows your
4241 signed integers. See L<perlfunc/pack>.
4245 (W io) A single call to write() produced more lines than can fit on a
4246 page. See L<perlform>.
4250 (P) An internal error.
4252 =item panic: attempt to call %s in %s
4254 (P) One of the file test operators entered a code branch that calls
4255 an ACL related-function, but that function is not available on this
4256 platform. Earlier checks mean that it should not be possible to
4257 enter this branch on this platform.
4259 =item panic: child pseudo-process was never scheduled
4261 (P) A child pseudo-process in the ithreads implementation on Windows
4262 was not scheduled within the time period allowed and therefore was not
4263 able to initialize properly.
4265 =item panic: ck_grep, type=%u
4267 (P) Failed an internal consistency check trying to compile a grep.
4269 =item panic: ck_split, type=%u
4271 (P) Failed an internal consistency check trying to compile a split.
4273 =item panic: corrupt saved stack index %ld
4275 (P) The savestack was requested to restore more localized values than
4276 there are in the savestack.
4278 =item panic: del_backref
4280 (P) Failed an internal consistency check while trying to reset a weak
4285 (P) We popped the context stack to an eval context, and then discovered
4286 it wasn't an eval context.
4288 =item panic: do_subst
4290 (P) The internal pp_subst() routine was called with invalid operational
4293 =item panic: do_trans_%s
4295 (P) The internal do_trans routines were called with invalid operational
4298 =item panic: fold_constants JMPENV_PUSH returned %d
4300 (P) While attempting folding constants an exception other than an C<eval>
4303 =item panic: frexp: %f
4305 (P) The library function frexp() failed, making printf("%f") impossible.
4307 =item panic: goto, type=%u, ix=%ld
4309 (P) We popped the context stack to a context with the specified label,
4310 and then discovered it wasn't a context we know how to do a goto in.
4312 =item panic: gp_free failed to free glob pointer
4314 (P) The internal routine used to clear a typeglob's entries tried
4315 repeatedly, but each time something re-created entries in the glob.
4316 Most likely the glob contains an object with a reference back to
4317 the glob and a destructor that adds a new object to the glob.
4319 =item panic: INTERPCASEMOD, %s
4321 (P) The lexer got into a bad state at a case modifier.
4323 =item panic: INTERPCONCAT, %s
4325 (P) The lexer got into a bad state parsing a string with brackets.
4327 =item panic: kid popen errno read
4329 (F) A forked child returned an incomprehensible message about its errno.
4331 =item panic: last, type=%u
4333 (P) We popped the context stack to a block context, and then discovered
4334 it wasn't a block context.
4336 =item panic: leave_scope clearsv
4338 (P) A writable lexical variable became read-only somehow within the
4341 =item panic: leave_scope inconsistency %u
4343 (P) The savestack probably got out of sync. At least, there was an
4344 invalid enum on the top of it.
4346 =item panic: magic_killbackrefs
4348 (P) Failed an internal consistency check while trying to reset all weak
4349 references to an object.
4351 =item panic: malloc, %s
4353 (P) Something requested a negative number of bytes of malloc.
4355 =item panic: memory wrap
4357 (P) Something tried to allocate either more memory than possible or a
4360 =item panic: pad_alloc, %p!=%p
4362 (P) The compiler got confused about which scratch pad it was allocating
4363 and freeing temporaries and lexicals from.
4365 =item panic: pad_free curpad, %p!=%p
4367 (P) The compiler got confused about which scratch pad it was allocating
4368 and freeing temporaries and lexicals from.
4370 =item panic: pad_free po
4372 (P) A zero scratch pad offset was detected internally. An attempt was
4373 made to free a target that had not been allocated to begin with.
4375 =item panic: pad_reset curpad, %p!=%p
4377 (P) The compiler got confused about which scratch pad it was allocating
4378 and freeing temporaries and lexicals from.
4380 =item panic: pad_sv po
4382 (P) A zero scratch pad offset was detected internally. Most likely
4383 an operator needed a target but that target had not been allocated
4384 for whatever reason.
4386 =item panic: pad_swipe curpad, %p!=%p
4388 (P) The compiler got confused about which scratch pad it was allocating
4389 and freeing temporaries and lexicals from.
4391 =item panic: pad_swipe po
4393 (P) An invalid scratch pad offset was detected internally.
4395 =item panic: pp_iter, type=%u
4397 (P) The foreach iterator got called in a non-loop context frame.
4399 =item panic: pp_match%s
4401 (P) The internal pp_match() routine was called with invalid operational
4404 =item panic: pp_split, pm=%p, s=%p
4406 (P) Something terrible went wrong in setting up for the split.
4408 =item panic: realloc, %s
4410 (P) Something requested a negative number of bytes of realloc.
4412 =item panic: reference miscount on nsv in sv_replace() (%d != 1)
4414 (P) The internal sv_replace() function was handed a new SV with a
4415 reference count other than 1.
4417 =item panic: restartop in %s
4419 (P) Some internal routine requested a goto (or something like it), and
4420 didn't supply the destination.
4422 =item panic: return, type=%u
4424 (P) We popped the context stack to a subroutine or eval context, and
4425 then discovered it wasn't a subroutine or eval context.
4427 =item panic: scan_num, %s
4429 (P) scan_num() got called on something that wasn't a number.
4431 =item panic: Sequence (?{...}): no code block found in regex m/%s/
4433 (P) While compiling a pattern that has embedded (?{}) or (??{}) code
4434 blocks, perl couldn't locate the code block that should have already been
4435 seen and compiled by perl before control passed to the regex compiler.
4437 =item panic: strxfrm() gets absurd - a => %u, ab => %u
4439 (P) The interpreter's sanity check of the C function strxfrm() failed.
4440 In your current locale the returned transformation of the string "ab"
4441 is shorter than that of the string "a", which makes no sense.
4443 =item panic: sv_chop %s
4445 (P) The sv_chop() routine was passed a position that is not within the
4446 scalar's string buffer.
4448 =item panic: sv_insert, midend=%p, bigend=%p
4450 (P) The sv_insert() routine was told to remove more string than there
4453 =item panic: top_env
4455 (P) The compiler attempted to do a goto, or something weird like that.
4457 =item panic: unimplemented op %s (#%d) called
4459 (P) The compiler is screwed up and attempted to use an op that isn't
4460 permitted at run time.
4462 =item panic: utf16_to_utf8: odd bytelen
4464 (P) Something tried to call utf16_to_utf8 with an odd (as opposed
4465 to even) byte length.
4467 =item panic: utf16_to_utf8_reversed: odd bytelen
4469 (P) Something tried to call utf16_to_utf8_reversed with an odd (as opposed
4470 to even) byte length.
4472 =item panic: yylex, %s
4474 (P) The lexer got into a bad state while processing a case modifier.
4476 =item Parentheses missing around "%s" list
4478 (W parenthesis) You said something like
4484 my ($foo, $bar) = @_;
4486 Remember that "my", "our", "local" and "state" bind tighter than comma.
4488 =item Parsing code internal error (%s)
4490 (F) Parsing code supplied by an extension violated the parser's API in
4493 =item Passing malformed UTF-8 to "%s" is deprecated
4495 (D deprecated, utf8) This message indicates a bug either in the Perl
4496 core or in XS code. Such code was trying to find out if a character,
4497 allegedly stored internally encoded as UTF-8, was of a given type, such
4498 as being punctuation or a digit. But the character was not encoded in
4499 legal UTF-8. The C<%s> is replaced by a string that can be used by
4500 knowledgeable people to determine what the type being checked against
4501 was. If C<utf8> warnings are enabled, a further message is raised,
4502 giving details of the malformation.
4504 =item Pattern subroutine nesting without pos change exceeded limit in regex
4506 (F) You used a pattern that uses too many nested subpattern calls without
4507 consuming any text. Restructure the pattern so text is consumed before
4508 the nesting limit is exceeded.
4510 =item C<-p> destination: %s
4512 (F) An error occurred during the implicit output invoked by the C<-p>
4513 command-line switch. (This output goes to STDOUT unless you've
4514 redirected it with select().)
4516 =item Perl API version %s of %s does not match %s
4518 (F) The XS module in question was compiled against a different incompatible
4519 version of Perl than the one that has loaded the XS module.
4521 =item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
4522 utility to report; in regex; marked by S<<-- HERE> in m/%s/
4524 (S regexp) You used a regular expression with case-insensitive matching,
4525 and there is a bug in Perl in which the built-in regular expression
4526 folding rules are not accurate. This may lead to incorrect results.
4527 Please report this as a bug using the L<perlbug> utility.
4529 =item PerlIO layer ':win32' is experimental
4531 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
4532 experimental. If you want to take the risk of using this layer,
4533 simply disable this warning:
4535 no warnings "experimental::win32_perlio";
4537 =item Perl_my_%s() not available
4539 (F) Your platform has very uncommon byte-order and integer size,
4540 so it was not possible to set up some or all fixed-width byte-order
4541 conversion functions. This is only a problem when you're using the
4542 '<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
4544 =item Perl %s required (did you mean %s?)--this is only %s, stopped
4546 (F) The code you are trying to run has asked for a newer version of
4547 Perl than you are running. Perhaps C<use 5.10> was written instead
4548 of C<use 5.010> or C<use v5.10>. Without the leading C<v>, the number is
4549 interpreted as a decimal, with every three digits after the
4550 decimal point representing a part of the version number. So 5.10
4551 is equivalent to v5.100.
4553 =item Perl %s required--this is only %s, stopped
4555 (F) The module in question uses features of a version of Perl more
4556 recent than the currently running version. How long has it been since
4557 you upgraded, anyway? See L<perlfunc/require>.
4559 =item PERL_SH_DIR too long
4561 (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
4562 C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
4564 =item PERL_SIGNALS illegal: "%s"
4566 (X) See L<perlrun/PERL_SIGNALS> for legal values.
4568 =item Perls since %s too modern--this is %s, stopped
4570 (F) The code you are trying to run claims it will not run
4571 on the version of Perl you are using because it is too new.
4572 Maybe the code needs to be updated, or maybe it is simply
4573 wrong and the version check should just be removed.
4575 =item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only partially set
4577 (S) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
4578 contained a non hex character. This could mean you are not using the
4579 hash seed you think you are.
4581 =item perl: warning: Setting locale failed.
4583 (S) The whole warning message will look something like:
4585 perl: warning: Setting locale failed.
4586 perl: warning: Please check that your locale settings:
4589 are supported and installed on your system.
4590 perl: warning: Falling back to the standard locale ("C").
4592 Exactly what were the failed locale settings varies. In the above the
4593 settings were that the LC_ALL was "En_US" and the LANG had no value.
4594 This error means that Perl detected that you and/or your operating
4595 system supplier and/or system administrator have set up the so-called
4596 locale system but Perl could not use those settings. This was not
4597 dead serious, fortunately: there is a "default locale" called "C" that
4598 Perl can and will use, and the script will be run. Before you really
4599 fix the problem, however, you will get the same error message each
4600 time you run Perl. How to really fix the problem can be found in
4601 L<perllocale> section B<LOCALE PROBLEMS>.
4603 =item perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
4605 (S) Perl was run with the environment variable PERL_PERTURB_KEYS defined
4606 but containing an unexpected value. The legal values of this setting
4609 Numeric | String | Result
4610 --------+---------------+-----------------------------------------
4611 0 | NO | Disables key traversal randomization
4612 1 | RANDOM | Enables full key traversal randomization
4613 2 | DETERMINISTIC | Enables repeatable key traversal
4616 Both numeric and string values are accepted, but note that string values are
4617 case sensitive. The default for this setting is "RANDOM" or 1.
4619 =item pid %x not a child
4621 (W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
4622 process which isn't a subprocess of the current process. While this is
4623 fine from VMS' perspective, it's probably not what you intended.
4625 =item 'P' must have an explicit size in unpack
4627 (F) The unpack format P must have an explicit size, not "*".
4629 =item POSIX class [:%s:] unknown in regex; marked by S<<-- HERE> in m/%s/
4631 (F) The class in the character class [: :] syntax is unknown. The S<<-- HERE>
4632 shows whereabouts in the regular expression the problem was discovered.
4633 Note that the POSIX character classes do B<not> have the C<is> prefix
4634 the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
4635 not C<isprint>. See L<perlre>.
4637 =item POSIX getpgrp can't take an argument
4639 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
4640 the BSD version, which takes a pid.
4642 =item POSIX syntax [%c %c] belongs inside character classes in regex; marked by
4643 S<<-- HERE> in m/%s/
4645 (W regexp) The character class constructs [: :], [= =], and [. .] go
4646 I<inside> character classes, the [] are part of the construct, for example:
4647 /[012[:alpha:]345]/. Note that [= =] and [. .] are not currently
4648 implemented; they are simply placeholders for future extensions and
4649 will cause fatal errors. The S<<-- HERE> shows whereabouts in the regular
4650 expression the problem was discovered. See L<perlre>.
4652 =item POSIX syntax [. .] is reserved for future extensions in regex; marked by
4653 S<<-- HERE> in m/%s/
4655 (F) Within regular expression character classes ([]) the syntax beginning
4656 with "[." and ending with ".]" is reserved for future extensions. If you
4657 need to represent those character sequences inside a regular expression
4658 character class, just quote the square brackets with the backslash: "\[."
4659 and ".\]". The S<<-- HERE> shows whereabouts in the regular expression the
4660 problem was discovered. See L<perlre>.
4662 =item POSIX syntax [= =] is reserved for future extensions in regex; marked by
4663 S<<-- HERE> in m/%s/
4665 (F) Within regular expression character classes ([]) the syntax beginning
4666 with "[=" and ending with "=]" is reserved for future extensions. If you
4667 need to represent those character sequences inside a regular expression
4668 character class, just quote the square brackets with the backslash: "\[="
4669 and "=\]". The S<<-- HERE> shows whereabouts in the regular expression the
4670 problem was discovered. See L<perlre>.
4672 =item Possible attempt to put comments in qw() list
4674 (W qw) qw() lists contain items separated by whitespace; as with literal
4675 strings, comment characters are not ignored, but are instead treated as
4676 literal data. (You may have used different delimiters than the
4677 parentheses shown here; braces are also frequently used.)
4679 You probably wrote something like this:
4686 when you should have written this:
4693 If you really want comments, build your list the
4694 old-fashioned way, with quotes and commas:
4698 'b', # another comment
4701 =item Possible attempt to separate words with commas
4703 (W qw) qw() lists contain items separated by whitespace; therefore
4704 commas aren't needed to separate the items. (You may have used
4705 different delimiters than the parentheses shown here; braces are also
4708 You probably wrote something like this:
4712 which puts literal commas into some of the list items. Write it without
4713 commas if you don't want them to appear in your data:
4717 =item Possible memory corruption: %s overflowed 3rd argument
4719 (F) An ioctl() or fcntl() returned more than Perl was bargaining for.
4720 Perl guesses a reasonable buffer size, but puts a sentinel byte at the
4721 end of the buffer just in case. This sentinel byte got clobbered, and
4722 Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
4724 =item Possible precedence issue with control flow operator
4726 (W syntax) There is a possible problem with the mixing of a control
4727 flow operator (e.g. C<return>) and a low-precedence operator like
4730 sub { return $a or $b; }
4734 sub { (return $a) or $b; }
4736 Which is effectively just:
4740 Either use parentheses or the high-precedence variant of the operator.
4742 Note this may be also triggered for constructs like:
4746 =item Possible precedence problem on bitwise %s operator
4748 (W precedence) Your program uses a bitwise logical operator in conjunction
4749 with a numeric comparison operator, like this :
4751 if ($x & $y == 0) { ... }
4753 This expression is actually equivalent to C<$x & ($y == 0)>, due to the
4754 higher precedence of C<==>. This is probably not what you want. (If you
4755 really meant to write this, disable the warning, or, better, put the
4756 parentheses explicitly and write C<$x & ($y == 0)>).
4758 =item Possible unintended interpolation of $\ in regex
4760 (W ambiguous) You said something like C<m/$\/> in a regex.
4761 The regex C<m/foo$\s+bar/m> translates to: match the word 'foo', the output
4762 record separator (see L<perlvar/$\>) and the letter 's' (one time or more)
4763 followed by the word 'bar'.
4765 If this is what you intended then you can silence the warning by using
4766 C<m/${\}/> (for example: C<m/foo${\}s+bar/>).
4768 If instead you intended to match the word 'foo' at the end of the line
4769 followed by whitespace and the word 'bar' on the next line then you can use
4770 C<m/$(?)\/> (for example: C<m/foo$(?)\s+bar/>).
4772 =item Possible unintended interpolation of %s in string
4774 (W ambiguous) You said something like '@foo' in a double-quoted string
4775 but there was no array C<@foo> in scope at the time. If you wanted a
4776 literal @foo, then write it as \@foo; otherwise find out what happened
4777 to the array you apparently lost track of.
4779 =item Precedence problem: open %s should be open(%s)
4781 (S precedence) The old irregular construct
4785 is now misinterpreted as
4789 because of the strict regularization of Perl 5's grammar into unary and
4790 list operators. (The old open was a little of both.) You must put
4791 parentheses around the filehandle, or use the new "or" operator instead
4794 =item Premature end of script headers
4798 =item printf() on closed filehandle %s
4800 (W closed) The filehandle you're writing to got itself closed sometime
4801 before now. Check your control flow.
4803 =item print() on closed filehandle %s
4805 (W closed) The filehandle you're printing on got itself closed sometime
4806 before now. Check your control flow.
4808 =item Process terminated by SIG%s
4810 (W) This is a standard message issued by OS/2 applications, while *nix
4811 applications die in silence. It is considered a feature of the OS/2
4812 port. One can easily disable this by appropriate sighandlers, see
4813 L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
4816 =item Property '%s' is unknown in regex; marked by S<<-- HERE> in m/%s/
4818 (F) The named property which you specified via C<\p> or C<\P> is not one
4819 known to Perl. Perhaps you misspelled the name? See
4820 L<perluniprops/Properties accessible through \p{} and \P{}>
4821 for a complete list of available official
4822 properties. If it is a L<user-defined property|perlunicode/User-Defined Character Properties>
4823 it must have been defined by the time the regular expression is
4826 =item Prototype after '%c' for %s : %s
4828 (W illegalproto) A character follows % or @ in a prototype. This is
4829 useless, since % and @ gobble the rest of the subroutine arguments.
4831 =item Prototype mismatch: %s vs %s
4833 (S prototype) The subroutine being declared or defined had previously been
4834 declared or defined with a different function prototype.
4836 =item Prototype not terminated
4838 (F) You've omitted the closing parenthesis in a function prototype
4841 =item Prototype '%s' overridden by attribute 'prototype(%s)' in %s
4843 (W prototype) A prototype was declared in both the parentheses after
4844 the sub name and via the prototype attribute. The prototype in
4845 parentheses is useless, since it will be replaced by the prototype
4846 from the attribute before it's ever used.
4848 =item Quantifier follows nothing in regex; marked by S<<-- HERE> in m/%s/
4850 (F) You started a regular expression with a quantifier. Backslash it if
4851 you meant it literally. The S<<-- HERE> shows whereabouts in the regular
4852 expression the problem was discovered. See L<perlre>.
4854 =item Quantifier in {,} bigger than %d in regex; marked by S<<-- HERE> in m/%s/
4856 (F) There is currently a limit to the size of the min and max values of
4857 the {min,max} construct. The S<<-- HERE> shows whereabouts in the regular
4858 expression the problem was discovered. See L<perlre>.
4860 =item Quantifier {n,m} with n > m can't match in regex
4862 =item Quantifier {n,m} with n > m can't match in regex; marked by
4863 S<<-- HERE> in m/%s/
4865 (W regexp) Minima should be less than or equal to maxima. If you really
4866 want your regexp to match something 0 times, just put {0}.
4868 =item Quantifier unexpected on zero-length expression in regex m/%s/
4870 (W regexp) You applied a regular expression quantifier in a place where
4871 it makes no sense, such as on a zero-width assertion. Try putting the
4872 quantifier inside the assertion instead. For example, the way to match
4873 "abc" provided that it is followed by three repetitions of "xyz" is
4874 C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
4876 =item Range iterator outside integer range
4878 (F) One (or both) of the numeric arguments to the range operator ".."
4879 are outside the range which can be represented by integers internally.
4880 One possible workaround is to force Perl to use magical string increment
4881 by prepending "0" to your numbers.
4883 =item Ranges of ASCII printables should be some subset of "0-9", "A-Z", or
4884 "a-z" in regex; marked by S<<-- HERE> in m/%s/
4886 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
4888 Stricter rules help to find typos and other errors. Perhaps you didn't
4889 even intend a range here, if the C<"-"> was meant to be some other
4890 character, or should have been escaped (like C<"\-">). If you did
4891 intend a range, the one that was used is not portable between ASCII and
4892 EBCDIC platforms, and doesn't have an obvious meaning to a casual
4895 [3-7] # OK; Obvious and portable
4896 [d-g] # OK; Obvious and portable
4897 [A-Y] # OK; Obvious and portable
4898 [A-z] # WRONG; Not portable; not clear what is meant
4899 [a-Z] # WRONG; Not portable; not clear what is meant
4900 [%-.] # WRONG; Not portable; not clear what is meant
4901 [\x41-Z] # WRONG; Not portable; not obvious to non-geek
4903 (You can force portability by specifying a Unicode range, which means that
4904 the endpoints are specified by
4905 L<C<\N{...}>|perlrecharclass/Character Ranges>, but the meaning may
4906 still not be obvious.)
4907 The stricter rules require that ranges that start or stop with an ASCII
4908 character that is not a control have all their endpoints be the literal
4909 character, and not some escape sequence (like C<"\x41">), and the ranges
4910 must be all digits, or all uppercase letters, or all lowercase letters.
4912 =item Ranges of digits should be from the same group in regex; marked by
4913 S<<-- HERE> in m/%s/
4915 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
4917 Stricter rules help to find typos and other errors. You included a
4918 range, and at least one of the end points is a decimal digit. Under the
4919 stricter rules, when this happens, both end points should be digits in
4920 the same group of 10 consecutive digits.
4922 =item readdir() attempted on invalid dirhandle %s
4924 (W io) The dirhandle you're reading from is either closed or not really
4925 a dirhandle. Check your control flow.
4927 =item readline() on closed filehandle %s
4929 (W closed) The filehandle you're reading from got itself closed sometime
4930 before now. Check your control flow.
4932 =item read() on closed filehandle %s
4934 (W closed) You tried to read from a closed filehandle.
4936 =item read() on unopened filehandle %s
4938 (W unopened) You tried to read from a filehandle that was never opened.
4940 =item Reallocation too large: %x
4942 (F) You can't allocate more than 64K on an MS-DOS machine.
4944 =item realloc() of freed memory ignored
4946 (S malloc) An internal routine called realloc() on something that had
4949 =item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
4951 (S debugging) You can't use the B<-D> option unless the code to produce
4952 the desired output is compiled into Perl, which entails some overhead,
4953 which is why it's currently left out of your copy.
4955 =item Recursive call to Perl_load_module in PerlIO_find_layer
4957 (P) It is currently not permitted to load modules when creating
4958 a filehandle inside an %INC hook. This can happen with C<open my
4959 $fh, '<', \$scalar>, which implicitly loads PerlIO::scalar. Try
4960 loading PerlIO::scalar explicitly first.
4962 =item Recursive inheritance detected in package '%s'
4964 (F) While calculating the method resolution order (MRO) of a package, Perl
4965 believes it found an infinite loop in the C<@ISA> hierarchy. This is a
4966 crude check that bails out after 100 levels of C<@ISA> depth.
4968 =item Redundant argument in %s
4970 (W redundant) You called a function with more arguments than other
4971 arguments you supplied indicated would be needed. Currently only
4972 emitted when a printf-type format required fewer arguments than were
4973 supplied, but might be used in the future for e.g. L<perlfunc/pack>.
4975 =item refcnt_dec: fd %d%s
4977 =item refcnt: fd %d%s
4979 =item refcnt_inc: fd %d%s
4981 (P) Perl's I/O implementation failed an internal consistency check. If
4982 you see this message, something is very wrong.
4984 =item Reference found where even-sized list expected
4986 (W misc) You gave a single reference where Perl was expecting a list
4987 with an even number of elements (for assignment to a hash). This
4988 usually means that you used the anon hash constructor when you meant
4989 to use parens. In any case, a hash requires key/value B<pairs>.
4991 %hash = { one => 1, two => 2, }; # WRONG
4992 %hash = [ qw/ an anon array / ]; # WRONG
4993 %hash = ( one => 1, two => 2, ); # right
4994 %hash = qw( one 1 two 2 ); # also fine
4996 =item Reference is already weak
4998 (W misc) You have attempted to weaken a reference that is already weak.
4999 Doing so has no effect.
5001 =item Reference to invalid group 0 in regex; marked by S<<-- HERE> in m/%s/
5003 (F) You used C<\g0> or similar in a regular expression. You may refer
5004 to capturing parentheses only with strictly positive integers
5005 (normal backreferences) or with strictly negative integers (relative
5006 backreferences). Using 0 does not make sense.
5008 =item Reference to nonexistent group in regex; marked by S<<-- HERE> in
5011 (F) You used something like C<\7> in your regular expression, but there are
5012 not at least seven sets of capturing parentheses in the expression. If
5013 you wanted to have the character with ordinal 7 inserted into the regular
5014 expression, prepend zeroes to make it three digits long: C<\007>
5016 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5019 =item Reference to nonexistent named group in regex; marked by S<<-- HERE>
5022 (F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
5023 expression, but there is no corresponding named capturing parentheses
5024 such as C<(?'NAME'...)> or C<< (?<NAME>...) >>. Check if the name has been
5025 spelled correctly both in the backreference and the declaration.
5027 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5030 =item Reference to nonexistent or unclosed group in regex; marked by
5031 S<<-- HERE> in m/%s/
5033 (F) You used something like C<\g{-7}> in your regular expression, but there
5034 are not at least seven sets of closed capturing parentheses in the
5035 expression before where the C<\g{-7}> was located.
5037 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5040 =item regexp memory corruption
5042 (P) The regular expression engine got confused by what the regular
5043 expression compiler gave it.
5045 =item Regexp modifier "/%c" may appear a maximum of twice
5047 =item Regexp modifier "%c" may appear a maximum of twice in regex; marked
5048 by S<<-- HERE> in m/%s/
5050 (F) The regular expression pattern had too many occurrences
5051 of the specified modifier. Remove the extraneous ones.
5053 =item Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
5056 (F) Turning off the given modifier has the side effect of turning on
5057 another one. Perl currently doesn't allow this. Reword the regular
5058 expression to use the modifier you want to turn on (and place it before
5059 the minus), instead of the one you want to turn off.
5061 =item Regexp modifier "/%c" may not appear twice
5063 =item Regexp modifier "%c" may not appear twice in regex; marked by <--
5066 (F) The regular expression pattern had too many occurrences
5067 of the specified modifier. Remove the extraneous ones.
5069 =item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5071 =item Regexp modifiers "%c" and "%c" are mutually exclusive in regex;
5072 marked by S<<-- HERE> in m/%s/
5074 (F) The regular expression pattern had more than one of these
5075 mutually exclusive modifiers. Retain only the modifier that is
5076 supposed to be there.
5078 =item Regexp out of space in regex m/%s/
5080 (P) A "can't happen" error, because safemalloc() should have caught it
5083 =item Repeated format line will never terminate (~~ and @#)
5085 (F) Your format contains the ~~ repeat-until-blank sequence and a
5086 numeric field that will never go blank so that the repetition never
5087 terminates. You might use ^# instead. See L<perlform>.
5089 =item Replacement list is longer than search list
5091 (W misc) You have used a replacement list that is longer than the
5092 search list. So the additional elements in the replacement list
5095 =item '%s' resolved to '\o{%s}%d'
5097 (W misc, regexp) You wrote something like C<\08>, or C<\179> in a
5098 double-quotish string. All but the last digit is treated as a single
5099 character, specified in octal. The last digit is the next character in
5100 the string. To tell Perl that this is indeed what you want, you can use
5101 the C<\o{ }> syntax, or use exactly three digits to specify the octal
5104 =item Reversed %s= operator
5106 (W syntax) You wrote your assignment operator backwards. The = must
5107 always come last, to avoid ambiguity with subsequent unary operators.
5109 =item rewinddir() attempted on invalid dirhandle %s
5111 (W io) The dirhandle you tried to do a rewinddir() on is either closed
5112 or not really a dirhandle. Check your control flow.
5114 =item Scalars leaked: %d
5116 (S internal) Something went wrong in Perl's internal bookkeeping
5117 of scalars: not all scalar variables were deallocated by the time
5118 Perl exited. What this usually indicates is a memory leak, which
5119 is of course bad, especially if the Perl program is intended to be
5122 =item Scalar value @%s[%s] better written as $%s[%s]
5124 (W syntax) You've used an array slice (indicated by @) to select a
5125 single element of an array. Generally it's better to ask for a scalar
5126 value (indicated by $). The difference is that C<$foo[&bar]> always
5127 behaves like a scalar, both when assigning to it and when evaluating its
5128 argument, while C<@foo[&bar]> behaves like a list when you assign to it,
5129 and provides a list context to its subscript, which can do weird things
5130 if you're expecting only one subscript.
5132 On the other hand, if you were actually hoping to treat the array
5133 element as a list, you need to look into how references work, because
5134 Perl will not magically convert between scalars and lists for you. See
5137 =item Scalar value @%s{%s} better written as $%s{%s}
5139 (W syntax) You've used a hash slice (indicated by @) to select a single
5140 element of a hash. Generally it's better to ask for a scalar value
5141 (indicated by $). The difference is that C<$foo{&bar}> always behaves
5142 like a scalar, both when assigning to it and when evaluating its
5143 argument, while C<@foo{&bar}> behaves like a list when you assign to it,
5144 and provides a list context to its subscript, which can do weird things
5145 if you're expecting only one subscript.
5147 On the other hand, if you were actually hoping to treat the hash element
5148 as a list, you need to look into how references work, because Perl will
5149 not magically convert between scalars and lists for you. See
5152 =item Search pattern not terminated
5154 (F) The lexer couldn't find the final delimiter of a // or m{}
5155 construct. Remember that bracketing delimiters count nesting level.
5156 Missing the leading C<$> from a variable C<$m> may cause this error.
5158 Note that since Perl 5.10.0 a // can also be the I<defined-or>
5159 construct, not just the empty search pattern. Therefore code written
5160 in Perl 5.10.0 or later that uses the // as the I<defined-or> can be
5161 misparsed by pre-5.10.0 Perls as a non-terminated search pattern.
5163 =item seekdir() attempted on invalid dirhandle %s
5165 (W io) The dirhandle you are doing a seekdir() on is either closed or not
5166 really a dirhandle. Check your control flow.
5168 =item %sseek() on unopened filehandle
5170 (W unopened) You tried to use the seek() or sysseek() function on a
5171 filehandle that was either never opened or has since been closed.
5173 =item select not implemented
5175 (F) This machine doesn't implement the select() system call.
5177 =item Self-ties of arrays and hashes are not supported
5179 (F) Self-ties are of arrays and hashes are not supported in
5180 the current implementation.
5182 =item Semicolon seems to be missing
5184 (W semicolon) A nearby syntax error was probably caused by a missing
5185 semicolon, or possibly some other missing operator, such as a comma.
5187 =item semi-panic: attempt to dup freed string
5189 (S internal) The internal newSVsv() routine was called to duplicate a
5190 scalar that had previously been marked as free.
5192 =item sem%s not implemented
5194 (F) You don't have System V semaphore IPC on your system.
5196 =item send() on closed socket %s
5198 (W closed) The socket you're sending to got itself closed sometime
5199 before now. Check your control flow.
5201 =item Sequence "\c{" invalid
5203 (F) These three characters may not appear in sequence in a
5204 double-quotish context. This message is raised only on non-ASCII
5205 platforms (a different error message is output on ASCII ones). If you
5206 were intending to specify a control character with this sequence, you'll
5207 have to use a different way to specify it.
5209 =item Sequence (? incomplete in regex; marked by S<<-- HERE> in m/%s/
5211 (F) A regular expression ended with an incomplete extension (?. The
5212 S<<-- HERE> shows whereabouts in the regular expression the problem was
5213 discovered. See L<perlre>.
5215 =item Sequence (?%c...) not implemented in regex; marked by S<<-- HERE> in
5218 (F) A proposed regular expression extension has the character reserved
5219 but has not yet been written. The S<<-- HERE> shows whereabouts in the
5220 regular expression the problem was discovered. See L<perlre>.
5222 =item Sequence (?%s...) not recognized in regex; marked by S<<-- HERE> in
5225 (F) You used a regular expression extension that doesn't make sense.
5226 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5227 discovered. This may happen when using the C<(?^...)> construct to tell
5228 Perl to use the default regular expression modifiers, and you
5229 redundantly specify a default modifier. For other
5230 causes, see L<perlre>.
5232 =item Sequence (?#... not terminated in regex m/%s/
5234 (F) A regular expression comment must be terminated by a closing
5235 parenthesis. Embedded parentheses aren't allowed. See
5238 =item Sequence (?&... not terminated in regex; marked by S<<-- HERE> in
5241 (F) A named reference of the form C<(?&...)> was missing the final
5242 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5243 in the regular expression the problem was discovered.
5245 =item Sequence (?%c... not terminated in regex; marked by S<<-- HERE>
5248 (F) A named group of the form C<(?'...')> or C<< (?<...>) >> was missing the final
5249 closing quote or angle bracket. The S<<-- HERE> shows whereabouts in the
5250 regular expression the problem was discovered.
5252 =item Sequence (?(%c... not terminated in regex; marked by S<<-- HERE>
5255 (F) A named reference of the form C<(?('...')...)> or C<< (?(<...>)...) >> was
5256 missing the final closing quote or angle bracket after the name. The
5257 S<<-- HERE> shows whereabouts in the regular expression the problem was
5260 =item Sequence \%s... not terminated in regex; marked by S<<-- HERE> in
5263 (F) The regular expression expects a mandatory argument following the escape
5264 sequence and this has been omitted or incorrectly written.
5266 =item Sequence (?{...}) not terminated with ')'
5268 (F) The end of the perl code contained within the {...} must be
5269 followed immediately by a ')'.
5271 =item Sequence ?P=... not terminated in regex; marked by S<<-- HERE> in
5274 (F) A named reference of the form C<(?P=...)> was missing the final
5275 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5276 in the regular expression the problem was discovered.
5278 =item Sequence (?R) not terminated in regex m/%s/
5280 (F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
5283 =item Server error (a.k.a. "500 Server error")
5285 (A) This is the error message generally seen in a browser window
5286 when trying to run a CGI program (including SSI) over the web. The
5287 actual error text varies widely from server to server. The most
5288 frequently-seen variants are "500 Server error", "Method (something)
5289 not permitted", "Document contains no data", "Premature end of script
5290 headers", and "Did not produce a valid header".
5292 B<This is a CGI error, not a Perl error>.
5294 You need to make sure your script is executable, is accessible by
5295 the user CGI is running the script under (which is probably not the
5296 user account you tested it under), does not rely on any environment
5297 variables (like PATH) from the user it isn't running under, and isn't
5298 in a location where the CGI server can't find it, basically, more or
5299 less. Please see the following for more information:
5301 http://www.perl.org/CGI_MetaFAQ.html
5302 http://www.htmlhelp.org/faq/cgifaq.html
5303 http://www.w3.org/Security/Faq/
5305 You should also look at L<perlfaq9>.
5307 =item setegid() not implemented
5309 (F) You tried to assign to C<$)>, and your operating system doesn't
5310 support the setegid() system call (or equivalent), or at least Configure
5313 =item seteuid() not implemented
5315 (F) You tried to assign to C<< $> >>, and your operating system doesn't
5316 support the seteuid() system call (or equivalent), or at least Configure
5319 =item setpgrp can't take arguments
5321 (F) Your system has the setpgrp() from BSD 4.2, which takes no
5322 arguments, unlike POSIX setpgid(), which takes a process ID and process
5325 =item setrgid() not implemented
5327 (F) You tried to assign to C<$(>, and your operating system doesn't
5328 support the setrgid() system call (or equivalent), or at least Configure
5331 =item setruid() not implemented
5333 (F) You tried to assign to C<$<>, and your operating system doesn't
5334 support the setruid() system call (or equivalent), or at least Configure
5337 =item setsockopt() on closed socket %s
5339 (W closed) You tried to set a socket option on a closed socket. Did you
5340 forget to check the return value of your socket() call? See
5341 L<perlfunc/setsockopt>.
5343 =item Setting ${^ENCODING} is deprecated
5345 (D deprecated) You assigned a non-C<undef> value to C<${^ENCODING}>.
5346 This is deprecated; see C<L<perlvar/${^ENCODING}>> for details.
5348 =item Setting $/ to a reference to %s as a form of slurp is deprecated, treating as undef
5350 (D deprecated) You assigned a reference to a scalar to C<$/> where the
5351 referenced item is not a positive integer. In older perls this B<appeared>
5352 to work the same as setting it to C<undef> but was in fact internally
5353 different, less efficient and with very bad luck could have resulted in
5354 your file being split by a stringified form of the reference.
5356 In Perl 5.20.0 this was changed so that it would be B<exactly> the same as
5357 setting C<$/> to undef, with the exception that this warning would be
5360 You are recommended to change your code to set C<$/> to C<undef> explicitly
5361 if you wish to slurp the file. In future versions of Perl assigning
5362 a reference to will throw a fatal error.
5364 =item Setting $/ to %s reference is forbidden
5366 (F) You tried to assign a reference to a non integer to C<$/>. In older
5367 Perls this would have behaved similarly to setting it to a reference to
5368 a positive integer, where the integer was the address of the reference.
5369 As of Perl 5.20.0 this is a fatal error, to allow future versions of Perl
5370 to use non-integer refs for more interesting purposes.
5372 =item shm%s not implemented
5374 (F) You don't have System V shared memory IPC on your system.
5376 =item !=~ should be !~
5378 (W syntax) The non-matching operator is !~, not !=~. !=~ will be
5379 interpreted as the != (numeric not equal) and ~ (1's complement)
5380 operators: probably not what you intended.
5382 =item /%s/ should probably be written as "%s"
5384 (W syntax) You have used a pattern where Perl expected to find a string,
5385 as in the first argument to C<join>. Perl will treat the true or false
5386 result of matching the pattern against $_ as the string, which is
5387 probably not what you had in mind.
5389 =item shutdown() on closed socket %s
5391 (W closed) You tried to do a shutdown on a closed socket. Seems a bit
5394 =item SIG%s handler "%s" not defined
5396 (W signal) The signal handler named in %SIG doesn't, in fact, exist.
5397 Perhaps you put it into the wrong package?
5399 =item Slab leaked from cv %p
5401 (S) If you see this message, then something is seriously wrong with the
5402 internal bookkeeping of op trees. An op tree needed to be freed after
5403 a compilation error, but could not be found, so it was leaked instead.
5405 =item sleep(%u) too large
5407 (W overflow) You called C<sleep> with a number that was larger than
5408 it can reliably handle and C<sleep> probably slept for less time than
5411 =item Slurpy parameter not last
5413 (F) In a subroutine signature, you put something after a slurpy (array or
5414 hash) parameter. The slurpy parameter takes all the available arguments,
5415 so there can't be any left to fill later parameters.
5417 =item Smart matching a non-overloaded object breaks encapsulation
5419 (F) You should not use the C<~~> operator on an object that does not
5420 overload it: Perl refuses to use the object's underlying structure
5421 for the smart match.
5423 =item Smartmatch is experimental
5425 (S experimental::smartmatch) This warning is emitted if you
5426 use the smartmatch (C<~~>) operator. This is currently an experimental
5427 feature, and its details are subject to change in future releases of
5428 Perl. Particularly, its current behavior is noticed for being
5429 unnecessarily complex and unintuitive, and is very likely to be
5432 =item sort is now a reserved word
5434 (F) An ancient error message that almost nobody ever runs into anymore.
5435 But before sort was a keyword, people sometimes used it as a filehandle.
5437 =item Source filters apply only to byte streams
5439 (F) You tried to activate a source filter (usually by loading a
5440 source filter module) within a string passed to C<eval>. This is
5441 not permitted under the C<unicode_eval> feature. Consider using
5442 C<evalbytes> instead. See L<feature>.
5444 =item splice() offset past end of array
5446 (W misc) You attempted to specify an offset that was past the end of
5447 the array passed to splice(). Splicing will instead commence at the
5448 end of the array, rather than past it. If this isn't what you want,
5449 try explicitly pre-extending the array by assigning $#array = $offset.
5450 See L<perlfunc/splice>.
5454 (P) The split was looping infinitely. (Obviously, a split shouldn't
5455 iterate more times than there are characters of input, which is what
5456 happened.) See L<perlfunc/split>.
5458 =item Statement unlikely to be reached
5460 (W exec) You did an exec() with some statement after it other than a
5461 die(). This is almost always an error, because exec() never returns
5462 unless there was a failure. You probably wanted to use system()
5463 instead, which does return. To suppress this warning, put the exec() in
5466 =item "state" subroutine %s can't be in a package
5468 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
5469 sense to try to declare one with a package qualifier on the front.
5471 =item "state %s" used in sort comparison
5473 (W syntax) The package variables $a and $b are used for sort comparisons.
5474 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
5475 sort comparison block, and the variable had earlier been declared as a
5476 lexical variable. Either qualify the sort variable with the package
5477 name, or rename the lexical variable.
5479 =item "state" variable %s can't be in a package
5481 (F) Lexically scoped variables aren't in a package, so it doesn't make
5482 sense to try to declare one with a package qualifier on the front. Use
5483 local() if you want to localize a package variable.
5485 =item stat() on unopened filehandle %s
5487 (W unopened) You tried to use the stat() function on a filehandle that
5488 was either never opened or has since been closed.
5490 =item Strings with code points over 0xFF may not be mapped into in-memory file handles
5492 (W utf8) You tried to open a reference to a scalar for read or append
5493 where the scalar contained code points over 0xFF. In-memory files
5494 model on-disk files and can only contain bytes.
5496 =item Stub found while resolving method "%s" overloading "%s" in package "%s"
5498 (P) Overloading resolution over @ISA tree may be broken by importation
5499 stubs. Stubs should never be implicitly created, but explicit calls to
5500 C<can> may break this.
5502 =item Subroutine "&%s" is not available
5504 (W closure) During compilation, an inner named subroutine or eval is
5505 attempting to capture an outer lexical subroutine that is not currently
5506 available. This can happen for one of two reasons. First, the lexical
5507 subroutine may be declared in an outer anonymous subroutine that has
5508 not yet been created. (Remember that named subs are created at compile
5509 time, while anonymous subs are created at run-time.) For example,
5511 sub { my sub a {...} sub f { \&a } }
5513 At the time that f is created, it can't capture the current "a" sub,
5514 since the anonymous subroutine hasn't been created yet. Conversely, the
5515 following won't give a warning since the anonymous subroutine has by now
5516 been created and is live:
5518 sub { my sub a {...} eval 'sub f { \&a }' }->();
5520 The second situation is caused by an eval accessing a lexical subroutine
5521 that has gone out of scope, for example,
5529 Here, when the '\&a' in the eval is being compiled, f() is not currently
5530 being executed, so its &a is not available for capture.
5532 =item "%s" subroutine &%s masks earlier declaration in same %s
5534 (W misc) A "my" or "state" subroutine has been redeclared in the
5535 current scope or statement, effectively eliminating all access to
5536 the previous instance. This is almost always a typographical error.
5537 Note that the earlier subroutine will still exist until the end of
5538 the scope or until all closure references to it are destroyed.
5540 =item Subroutine %s redefined
5542 (W redefine) You redefined a subroutine. To suppress this warning, say
5545 no warnings 'redefine';
5546 eval "sub name { ... }";
5549 =item Subroutine "%s" will not stay shared
5551 (W closure) An inner (nested) I<named> subroutine is referencing a "my"
5552 subroutine defined in an outer named subroutine.
5554 When the inner subroutine is called, it will see the value of the outer
5555 subroutine's lexical subroutine as it was before and during the *first*
5556 call to the outer subroutine; in this case, after the first call to the
5557 outer subroutine is complete, the inner and outer subroutines will no
5558 longer share a common value for the lexical subroutine. In other words,
5559 it will no longer be shared. This will especially make a difference
5560 if the lexical subroutines accesses lexical variables declared in its
5563 This problem can usually be solved by making the inner subroutine
5564 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
5565 reference lexical subroutines in outer subroutines are created, they
5566 are automatically rebound to the current values of such lexical subs.
5568 =item Substitution loop
5570 (P) The substitution was looping infinitely. (Obviously, a substitution
5571 shouldn't iterate more times than there are characters of input, which
5572 is what happened.) See the discussion of substitution in
5573 L<perlop/"Regexp Quote-Like Operators">.
5575 =item Substitution pattern not terminated
5577 (F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
5578 construct. Remember that bracketing delimiters count nesting level.
5579 Missing the leading C<$> from variable C<$s> may cause this error.
5581 =item Substitution replacement not terminated
5583 (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
5584 construct. Remember that bracketing delimiters count nesting level.
5585 Missing the leading C<$> from variable C<$s> may cause this error.
5587 =item substr outside of string
5589 (W substr)(F) You tried to reference a substr() that pointed outside of
5590 a string. That is, the absolute value of the offset was larger than the
5591 length of the string. See L<perlfunc/substr>. This warning is fatal if
5592 substr is used in an lvalue context (as the left hand side of an
5593 assignment or as a subroutine argument for example).
5595 =item sv_upgrade from type %d down to type %d
5597 (P) Perl tried to force the upgrade of an SV to a type which was actually
5598 inferior to its current type.
5600 =item SWASHNEW didn't return an HV ref
5602 (P) Something went wrong internally when Perl was trying to look up
5605 =item Switch (?(condition)... contains too many branches in regex; marked by
5606 S<<-- HERE> in m/%s/
5608 (F) A (?(condition)if-clause|else-clause) construct can have at most
5609 two branches (the if-clause and the else-clause). If you want one or
5610 both to contain alternation, such as using C<this|that|other>, enclose
5611 it in clustering parentheses:
5613 (?(condition)(?:this|that|other)|else-clause)
5615 The S<<-- HERE> shows whereabouts in the regular expression the problem
5616 was discovered. See L<perlre>.
5618 =item Switch condition not recognized in regex; marked by S<<-- HERE> in
5621 (F) The condition part of a (?(condition)if-clause|else-clause) construct
5622 is not known. The condition must be one of the following:
5624 (1) (2) ... true if 1st, 2nd, etc., capture matched
5625 (<NAME>) ('NAME') true if named capture matched
5626 (?=...) (?<=...) true if subpattern matches
5627 (?!...) (?<!...) true if subpattern fails to match
5628 (?{ CODE }) true if code returns a true value
5629 (R) true if evaluating inside recursion
5630 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
5631 (R&NAME) true if directly inside named capture
5632 (DEFINE) always false; for defining named subpatterns
5634 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5635 discovered. See L<perlre>.
5637 =item Switch (?(condition)... not terminated in regex; marked by
5638 S<<-- HERE> in m/%s/
5640 (F) You omitted to close a (?(condition)...) block somewhere
5641 in the pattern. Add a closing parenthesis in the appropriate
5642 position. See L<perlre>.
5644 =item switching effective %s is not implemented
5646 (F) While under the C<use filetest> pragma, we cannot switch the real
5647 and effective uids or gids.
5651 (F) Probably means you had a syntax error. Common reasons include:
5653 A keyword is misspelled.
5654 A semicolon is missing.
5656 An opening or closing parenthesis is missing.
5657 An opening or closing brace is missing.
5658 A closing quote is missing.
5660 Often there will be another error message associated with the syntax
5661 error giving more information. (Sometimes it helps to turn on B<-w>.)
5662 The error message itself often tells you where it was in the line when
5663 it decided to give up. Sometimes the actual error is several tokens
5664 before this, because Perl is good at understanding random input.
5665 Occasionally the line number may be misleading, and once in a blue moon
5666 the only way to figure out what's triggering the error is to call
5667 C<perl -c> repeatedly, chopping away half the program each time to see
5668 if the error went away. Sort of the cybernetic version of S<20 questions>.
5670 =item syntax error at line %d: '%s' unexpected
5672 (A) You've accidentally run your script through the Bourne shell instead
5673 of Perl. Check the #! line, or manually feed your script into Perl
5676 =item syntax error in file %s at line %d, next 2 tokens "%s"
5678 (F) This error is likely to occur if you run a perl5 script through
5679 a perl4 interpreter, especially if the next 2 tokens are "use strict"
5680 or "my $var" or "our $var".
5682 =item Syntax error in (?[...]) in regex m/%s/
5684 (F) Perl could not figure out what you meant inside this construct; this
5685 notifies you that it is giving up trying.
5689 (F) The final summary message when a C<perl -c> succeeds.
5691 =item sysread() on closed filehandle %s
5693 (W closed) You tried to read from a closed filehandle.
5695 =item sysread() on unopened filehandle %s
5697 (W unopened) You tried to read from a filehandle that was never opened.
5699 =item System V %s is not implemented on this machine
5701 (F) You tried to do something with a function beginning with "sem",
5702 "shm", or "msg" but that System V IPC is not implemented in your
5703 machine. In some machines the functionality can exist but be
5704 unconfigured. Consult your system support.
5706 =item syswrite() on closed filehandle %s
5708 (W closed) The filehandle you're writing to got itself closed sometime
5709 before now. Check your control flow.
5711 =item C<-T> and C<-B> not implemented on filehandles
5713 (F) Perl can't peek at the stdio buffer of filehandles when it doesn't
5714 know about your kind of stdio. You'll have to use a filename instead.
5716 =item Target of goto is too deeply nested
5718 (F) You tried to use C<goto> to reach a label that was too deeply nested
5719 for Perl to reach. Perl is doing you a favor by refusing.
5721 =item telldir() attempted on invalid dirhandle %s
5723 (W io) The dirhandle you tried to telldir() is either closed or not really
5724 a dirhandle. Check your control flow.
5726 =item tell() on unopened filehandle
5728 (W unopened) You tried to use the tell() function on a filehandle that
5729 was either never opened or has since been closed.
5731 =item That use of $[ is unsupported
5733 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
5734 as a compiler directive. You may say only one of
5743 This is to prevent the problem of one module changing the array base out
5744 from under another module inadvertently. See L<perlvar/$[> and L<arybase>.
5746 =item The bitwise feature is experimental
5748 (S experimental::bitwise) This warning is emitted if you use bitwise
5749 operators (C<& | ^ ~ &. |. ^. ~.>) with the "bitwise" feature enabled.
5750 Simply suppress the warning if you want to use the feature, but know
5751 that in doing so you are taking the risk of using an experimental
5752 feature which may change or be removed in a future Perl version:
5754 no warnings "experimental::bitwise";
5755 use feature "bitwise";
5758 =item The crypt() function is unimplemented due to excessive paranoia.
5760 (F) Configure couldn't find the crypt() function on your machine,
5761 probably because your vendor didn't supply it, probably because they
5762 think the U.S. Government thinks it's a secret, or at least that they
5763 will continue to pretend that it is. And if you quote me on that, I
5766 =item The %s function is unimplemented
5768 (F) The function indicated isn't implemented on this architecture,
5769 according to the probings of Configure.
5771 =item The lexical_subs feature is experimental
5773 (S experimental::lexical_subs) This warning is emitted if you
5774 declare a sub with C<my> or C<state>. Simply suppress the warning
5775 if you want to use the feature, but know that in doing so you
5776 are taking the risk of using an experimental feature which may
5777 change or be removed in a future Perl version:
5779 no warnings "experimental::lexical_subs";
5780 use feature "lexical_subs";
5783 =item The regex_sets feature is experimental
5785 (S experimental::regex_sets) This warning is emitted if you
5786 use the syntax S<C<(?[ ])>> in a regular expression.
5787 The details of this feature are subject to change.
5788 if you want to use it, but know that in doing so you
5789 are taking the risk of using an experimental feature which may
5790 change in a future Perl version, you can do this to silence the
5793 no warnings "experimental::regex_sets";
5795 =item The signatures feature is experimental
5797 (S experimental::signatures) This warning is emitted if you unwrap a
5798 subroutine's arguments using a signature. Simply suppress the warning
5799 if you want to use the feature, but know that in doing so you are taking
5800 the risk of using an experimental feature which may change or be removed
5801 in a future Perl version:
5803 no warnings "experimental::signatures";
5804 use feature "signatures";
5805 sub foo ($left, $right) { ... }
5807 =item The stat preceding %s wasn't an lstat
5809 (F) It makes no sense to test the current stat buffer for symbolic
5810 linkhood if the last stat that wrote to the stat buffer already went
5811 past the symlink to get to the real file. Use an actual filename
5814 =item The 'unique' attribute may only be applied to 'our' variables
5816 (F) This attribute was never supported on C<my> or C<sub> declarations.
5818 =item This Perl can't reset CRTL environ elements (%s)
5820 =item This Perl can't set CRTL environ elements (%s=%s)
5822 (W internal) Warnings peculiar to VMS. You tried to change or delete an
5823 element of the CRTL's internal environ array, but your copy of Perl
5824 wasn't built with a CRTL that contained the setenv() function. You'll
5825 need to rebuild Perl with a CRTL that does, or redefine
5826 F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
5827 target of the change to
5828 %ENV which produced the warning.
5830 =item This Perl has not been built with support for randomized hash key traversal but something called Perl_hv_rand_set().
5832 (F) Something has attempted to use an internal API call which
5833 depends on Perl being compiled with the default support for randomized hash
5834 key traversal, but this Perl has been compiled without it. You should
5835 report this warning to the relevant upstream party, or recompile perl
5836 with default options.
5838 =item times not implemented
5840 (F) Your version of the C library apparently doesn't do times(). I
5841 suspect you're not running on Unix.
5843 =item "-T" is on the #! line, it must also be used on the command line
5845 (X) The #! line (or local equivalent) in a Perl script contains
5846 the B<-T> option (or the B<-t> option), but Perl was not invoked with
5847 B<-T> in its command line. This is an error because, by the time
5848 Perl discovers a B<-T> in a script, it's too late to properly taint
5849 everything from the environment. So Perl gives up.
5851 If the Perl script is being executed as a command using the #!
5852 mechanism (or its local equivalent), this error can usually be
5853 fixed by editing the #! line so that the B<-%c> option is a part of
5854 Perl's first argument: e.g. change C<perl -n -%c> to C<perl -%c -n>.
5856 If the Perl script is being executed as C<perl scriptname>, then the
5857 B<-%c> option must appear on the command line: C<perl -%c scriptname>.
5859 =item To%s: illegal mapping '%s'
5861 (F) You tried to define a customized To-mapping for lc(), lcfirst,
5862 uc(), or ucfirst() (or their string-inlined versions), but you
5863 specified an illegal mapping.
5864 See L<perlunicode/"User-Defined Character Properties">.
5866 =item Too deeply nested ()-groups
5868 (F) Your template contains ()-groups with a ridiculously deep nesting level.
5870 =item Too few args to syscall
5872 (F) There has to be at least one argument to syscall() to specify the
5873 system call to call, silly dilly.
5875 =item Too few arguments for subroutine
5877 (F) A subroutine using a signature received fewer arguments than required
5878 by the signature. The caller of the subroutine is presumably at fault.
5879 Inconveniently, this error will be reported at the location of the
5880 subroutine, not that of the caller.
5882 =item Too late for "-%s" option
5884 (X) The #! line (or local equivalent) in a Perl script contains the
5885 B<-M>, B<-m> or B<-C> option.
5887 In the case of B<-M> and B<-m>, this is an error because those options
5888 are not intended for use inside scripts. Use the C<use> pragma instead.
5890 The B<-C> option only works if it is specified on the command line as
5891 well (with the same sequence of letters or numbers following). Either
5892 specify this option on the command line, or, if your system supports
5893 it, make your script executable and run it directly instead of passing
5896 =item Too late to run %s block
5898 (W void) A CHECK or INIT block is being defined during run time proper,
5899 when the opportunity to run them has already passed. Perhaps you are
5900 loading a file with C<require> or C<do> when you should be using C<use>
5901 instead. Or perhaps you should put the C<require> or C<do> inside a
5904 =item Too many args to syscall
5906 (F) Perl supports a maximum of only 14 args to syscall().
5908 =item Too many arguments for %s
5910 (F) The function requires fewer arguments than you specified.
5912 =item Too many arguments for subroutine
5914 (F) A subroutine using a signature received more arguments than required
5915 by the signature. The caller of the subroutine is presumably at fault.
5916 Inconveniently, this error will be reported at the location of the
5917 subroutine, not that of the caller.
5921 (A) You've accidentally run your script through B<csh> instead of Perl.
5922 Check the #! line, or manually feed your script into Perl yourself.
5926 (A) You've accidentally run your script through B<csh> instead of Perl.
5927 Check the #! line, or manually feed your script into Perl yourself.
5929 =item Trailing \ in regex m/%s/
5931 (F) The regular expression ends with an unbackslashed backslash.
5932 Backslash it. See L<perlre>.
5934 =item Transliteration pattern not terminated
5936 (F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
5937 or y/// or y[][] construct. Missing the leading C<$> from variables
5938 C<$tr> or C<$y> may cause this error.
5940 =item Transliteration replacement not terminated
5942 (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
5943 y/// or y[][] construct.
5945 =item '%s' trapped by operation mask
5947 (F) You tried to use an operator from a Safe compartment in which it's
5948 disallowed. See L<Safe>.
5950 =item truncate not implemented
5952 (F) Your machine doesn't implement a file truncation mechanism that
5953 Configure knows about.
5955 =item Type of arg %d to &CORE::%s must be %s
5957 (F) The subroutine in question in the CORE package requires its argument
5958 to be a hard reference to data of the specified type. Overloading is
5959 ignored, so a reference to an object that is not the specified type, but
5960 nonetheless has overloading to handle it, will still not be accepted.
5962 =item Type of arg %d to %s must be %s (not %s)
5964 (F) This function requires the argument in that position to be of a
5965 certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
5966 %NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
5967 {EXPR} forms as an explicit dereference. See L<perlref>.
5969 =item umask not implemented
5971 (F) Your machine doesn't implement the umask function and you tried to
5972 use it to restrict permissions for yourself (EXPR & 0700).
5974 =item Unbalanced context: %d more PUSHes than POPs
5976 (S internal) The exit code detected an internal inconsistency in how
5977 many execution contexts were entered and left.
5979 =item Unbalanced saves: %d more saves than restores
5981 (S internal) The exit code detected an internal inconsistency in how
5982 many values were temporarily localized.
5984 =item Unbalanced scopes: %d more ENTERs than LEAVEs
5986 (S internal) The exit code detected an internal inconsistency in how
5987 many blocks were entered and left.
5989 =item Unbalanced string table refcount: (%d) for "%s"
5991 (S internal) On exit, Perl found some strings remaining in the shared
5992 string table used for copy on write and for hash keys. The entries
5993 should have been freed, so this indicates a bug somewhere.
5995 =item Unbalanced tmps: %d more allocs than frees
5997 (S internal) The exit code detected an internal inconsistency in how
5998 many mortal scalars were allocated and freed.
6000 =item Undefined format "%s" called
6002 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6003 another package? See L<perlform>.
6005 =item Undefined sort subroutine "%s" called
6007 (F) The sort comparison routine specified doesn't seem to exist.
6008 Perhaps it's in a different package? See L<perlfunc/sort>.
6010 =item Undefined subroutine &%s called
6012 (F) The subroutine indicated hasn't been defined, or if it was, it has
6013 since been undefined.
6015 =item Undefined subroutine called
6017 (F) The anonymous subroutine you're trying to call hasn't been defined,
6018 or if it was, it has since been undefined.
6020 =item Undefined subroutine in sort
6022 (F) The sort comparison routine specified is declared but doesn't seem
6023 to have been defined yet. See L<perlfunc/sort>.
6025 =item Undefined top format "%s" called
6027 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6028 another package? See L<perlform>.
6030 =item Undefined value assigned to typeglob
6032 (W misc) An undefined value was assigned to a typeglob, a la
6033 C<*foo = undef>. This does nothing. It's possible that you really mean
6036 =item %s: Undefined variable
6038 (A) You've accidentally run your script through B<csh> instead of Perl.
6039 Check the #! line, or manually feed your script into Perl yourself.
6041 =item Unescaped left brace in regex is deprecated, passed through in regex;
6042 marked by S<<-- HERE> in m/%s/
6044 (D deprecated, regexp) You used a literal C<"{"> character in a regular
6045 expression pattern. You should change to use C<"\{"> instead, because a
6046 future version of Perl (tentatively v5.26) will consider this to be a
6047 syntax error. If the pattern delimiters are also braces, any matching
6048 right brace (C<"}">) should also be escaped to avoid confusing the parser,
6053 =item unexec of %s into %s failed!
6055 (F) The unexec() routine failed for some reason. See your local FSF
6056 representative, who probably put it there in the first place.
6058 =item Unexpected binary operator '%c' with no preceding operand in regex;
6059 marked by S<<-- HERE> in m/%s/
6061 (F) You had something like this:
6065 where the C<"|"> is a binary operator with an operand on the right, but
6066 no operand on the left.
6068 =item Unexpected character in regex; marked by S<<-- HERE> in m/%s/
6070 (F) You had something like this:
6074 Within C<(?[ ])>, no literal characters are allowed unless they are
6075 within an inner pair of square brackets, like
6079 Another possibility is that you forgot a backslash. Perl isn't smart
6080 enough to figure out what you really meant.
6082 =item Unexpected constant lvalue entersub entry via type/targ %d:%d
6084 (P) When compiling a subroutine call in lvalue context, Perl failed an
6085 internal consistency check. It encountered a malformed op tree.
6087 =item Unexpected exit %u
6089 (S) exit() was called or the script otherwise finished gracefully when
6090 C<PERL_EXIT_WARN> was set in C<PL_exit_flags>.
6092 =item Unexpected exit failure %d
6094 (S) An uncaught die() was called when C<PERL_EXIT_WARN> was set in
6097 =item Unexpected ')' in regex; marked by S<<-- HERE> in m/%s/
6099 (F) You had something like this:
6101 (?[ ( \p{Digit} + ) ])
6103 The C<")"> is out-of-place. Something apparently was supposed to
6104 be combined with the digits, or the C<"+"> shouldn't be there, or
6105 something like that. Perl can't figure out what was intended.
6107 =item Unexpected '(' with no preceding operator in regex; marked by
6108 S<<-- HERE> in m/%s/
6110 (F) You had something like this:
6112 (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
6114 There should be an operator before the C<"(">, as there's
6115 no indication as to how the digits are to be combined
6116 with the characters in the Lao and Thai scripts.
6118 =item Unicode non-character U+%X is not recommended for open interchange
6120 (S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
6121 defined by the Unicode standard to be non-characters. Those
6122 are legal codepoints, but are reserved for internal use; so,
6123 applications shouldn't attempt to exchange them. An application
6124 may not be expecting any of these characters at all, and receiving
6125 them may lead to bugs. If you know what you are doing you can
6126 turn off this warning by C<no warnings 'nonchar';>.
6128 This is not really a "severe" error, but it is supposed to be
6129 raised by default even if warnings are not enabled, and currently
6130 the only way to do that in Perl is to mark it as serious.
6132 =item Unicode surrogate U+%X is illegal in UTF-8
6134 (S surrogate) You had a UTF-16 surrogate in a context where they are
6135 not considered acceptable. These code points, between U+D800 and
6136 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6137 internally allows all unsigned integer code points (up to the size limit
6138 available on your platform), including surrogates. But these can cause
6139 problems when being input or output, which is likely where this message
6140 came from. If you really really know what you are doing you can turn
6141 off this warning by C<no warnings 'surrogate';>.
6143 =item Unknown charname '%s'
6145 (F) The name you used inside C<\N{}> is unknown to Perl. Check the
6146 spelling. You can say C<use charnames ":loose"> to not have to be
6147 so precise about spaces, hyphens, and capitalization on standard Unicode
6148 names. (Any custom aliases that have been created must be specified
6149 exactly, regardless of whether C<:loose> is used or not.) This error may
6150 also happen if the C<\N{}> is not in the scope of the corresponding
6151 C<S<use charnames>>.
6155 (P) Perl was about to print an error message in C<$@>, but the C<$@> variable
6156 did not exist, even after an attempt to create it.
6158 =item Unknown open() mode '%s'
6160 (F) The second argument of 3-argument open() is not among the list
6161 of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
6162 C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
6164 =item Unknown PerlIO layer "%s"
6166 (W layer) An attempt was made to push an unknown layer onto the Perl I/O
6167 system. (Layers take care of transforming data between external and
6168 internal representations.) Note that some layers, such as C<mmap>,
6169 are not supported in all environments. If your program didn't
6170 explicitly request the failing operation, it may be the result of the
6171 value of the environment variable PERLIO.
6173 =item Unknown process %x sent message to prime_env_iter: %s
6175 (P) An error peculiar to VMS. Perl was reading values for %ENV before
6176 iterating over it, and someone else stuck a message in the stream of
6177 data Perl expected. Someone's very confused, or perhaps trying to
6178 subvert Perl's population of %ENV for nefarious purposes.
6180 =item Unknown regex modifier "%s"
6182 (F) Alphanumerics immediately following the closing delimiter
6183 of a regular expression pattern are interpreted by Perl as modifier
6184 flags for the regex. One of the ones you specified is invalid. One way
6185 this can happen is if you didn't put in white space between the end of
6186 the regex and a following alphanumeric operator:
6188 if ($a =~ /foo/and $bar == 3) { ... }
6190 The C<"a"> is a valid modifier flag, but the C<"n"> is not, and raises
6191 this error. Likely what was meant instead was:
6193 if ($a =~ /foo/ and $bar == 3) { ... }
6195 =item Unknown "re" subpragma '%s' (known ones are: %s)
6197 (W) You tried to use an unknown subpragma of the "re" pragma.
6199 =item Unknown switch condition (?(...)) in regex; marked by S<<-- HERE> in
6202 (F) The condition part of a (?(condition)if-clause|else-clause) construct
6203 is not known. The condition must be one of the following:
6205 (1) (2) ... true if 1st, 2nd, etc., capture matched
6206 (<NAME>) ('NAME') true if named capture matched
6207 (?=...) (?<=...) true if subpattern matches
6208 (?!...) (?<!...) true if subpattern fails to match
6209 (?{ CODE }) true if code returns a true value
6210 (R) true if evaluating inside recursion
6211 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
6212 (R&NAME) true if directly inside named capture
6213 (DEFINE) always false; for defining named subpatterns
6215 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6216 discovered. See L<perlre>.
6218 =item Unknown Unicode option letter '%c'
6220 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6221 of the C<-C> switch for the list of known options.
6223 =item Unknown Unicode option value %d
6225 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6226 of the C<-C> switch for the list of known options.
6228 =item Unknown verb pattern '%s' in regex; marked by S<<-- HERE> in m/%s/
6230 (F) You either made a typo or have incorrectly put a C<*> quantifier
6231 after an open brace in your pattern. Check the pattern and review
6232 L<perlre> for details on legal verb patterns.
6234 =item Unknown warnings category '%s'
6236 (F) An error issued by the C<warnings> pragma. You specified a warnings
6237 category that is unknown to perl at this point.
6239 Note that if you want to enable a warnings category registered by a
6240 module (e.g. C<use warnings 'File::Find'>), you must have loaded this
6243 =item Unmatched '[' in POSIX class in regex; marked by S<<-- HERE> in m/%s/
6245 (F) You had something like this:
6249 That should be written:
6253 =item Unmatched '%c' in POSIX class in regex; marked by S<<-- HERE> in
6256 (F) You had something like this:
6260 There should be a second C<":">, like this:
6264 =item Unmatched [ in regex; marked by S<<-- HERE> in m/%s/
6266 (F) The brackets around a character class must match. If you wish to
6267 include a closing bracket in a character class, backslash it or put it
6268 first. The S<<-- HERE> shows whereabouts in the regular expression the
6269 problem was discovered. See L<perlre>.
6271 =item Unmatched ( in regex; marked by S<<-- HERE> in m/%s/
6273 =item Unmatched ) in regex; marked by S<<-- HERE> in m/%s/
6275 (F) Unbackslashed parentheses must always be balanced in regular
6276 expressions. If you're a vi user, the % key is valuable for finding
6277 the matching parenthesis. The S<<-- HERE> shows whereabouts in the
6278 regular expression the problem was discovered. See L<perlre>.
6280 =item Unmatched right %s bracket
6282 (F) The lexer counted more closing curly or square brackets than opening
6283 ones, so you're probably missing a matching opening bracket. As a
6284 general rule, you'll find the missing one (so to speak) near the place
6285 you were last editing.
6287 =item Unquoted string "%s" may clash with future reserved word
6289 (W reserved) You used a bareword that might someday be claimed as a
6290 reserved word. It's best to put such a word in quotes, or capitalize it
6291 somehow, or insert an underbar into it. You might also declare it as a
6294 =item Unrecognized character %s; marked by S<<-- HERE> after %s near column
6297 (F) The Perl parser has no idea what to do with the specified character
6298 in your Perl script (or eval) near the specified column. Perhaps you
6299 tried to run a compressed script, a binary program, or a directory as
6302 =item Unrecognized escape \%c in character class in regex; marked by
6303 S<<-- HERE> in m/%s/
6305 (F) You used a backslash-character combination which is not
6306 recognized by Perl inside character classes. This is a fatal
6307 error when the character class is used within C<(?[ ])>.
6309 =item Unrecognized escape \%c in character class passed through in regex;
6310 marked by S<<-- HERE> in m/%s/
6312 (W regexp) You used a backslash-character combination which is not
6313 recognized by Perl inside character classes. The character was
6314 understood literally, but this may change in a future version of Perl.
6315 The S<<-- HERE> shows whereabouts in the regular expression the
6316 escape was discovered.
6318 =item Unrecognized escape \%c passed through
6320 (W misc) You used a backslash-character combination which is not
6321 recognized by Perl. The character was understood literally, but this may
6322 change in a future version of Perl.
6324 =item Unrecognized escape \%s passed through in regex; marked by
6325 S<<-- HERE> in m/%s/
6327 (W regexp) You used a backslash-character combination which is not
6328 recognized by Perl. The character(s) were understood literally, but
6329 this may change in a future version of Perl. The S<<-- HERE> shows
6330 whereabouts in the regular expression the escape was discovered.
6332 =item Unrecognized signal name "%s"
6334 (F) You specified a signal name to the kill() function that was not
6335 recognized. Say C<kill -l> in your shell to see the valid signal names
6338 =item Unrecognized switch: -%s (-h will show valid options)
6340 (F) You specified an illegal option to Perl. Don't do that. (If you
6341 think you didn't do that, check the #! line to see if it's supplying the
6342 bad switch on your behalf.)
6344 =item Unsuccessful %s on filename containing newline
6346 (W newline) A file operation was attempted on a filename, and that
6347 operation failed, PROBABLY because the filename contained a newline,
6348 PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
6350 =item Unsupported directory function "%s" called
6352 (F) Your machine doesn't support opendir() and readdir().
6354 =item Unsupported function %s
6356 (F) This machine doesn't implement the indicated function, apparently.
6357 At least, Configure doesn't think so.
6359 =item Unsupported function fork
6361 (F) Your version of executable does not support forking.
6363 Note that under some systems, like OS/2, there may be different flavors
6364 of Perl executables, some of which may support fork, some not. Try
6365 changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
6367 =item Unsupported script encoding %s
6369 (F) Your program file begins with a Unicode Byte Order Mark (BOM) which
6370 declares it to be in a Unicode encoding that Perl cannot read.
6372 =item Unsupported socket function "%s" called
6374 (F) Your machine doesn't support the Berkeley socket mechanism, or at
6375 least that's what Configure thought.
6377 =item Unterminated attribute list
6379 (F) The lexer found something other than a simple identifier at the
6380 start of an attribute, and it wasn't a semicolon or the start of a
6381 block. Perhaps you terminated the parameter list of the previous
6382 attribute too soon. See L<attributes>.
6384 =item Unterminated attribute parameter in attribute list
6386 (F) The lexer saw an opening (left) parenthesis character while parsing
6387 an attribute list, but the matching closing (right) parenthesis
6388 character was not found. You may need to add (or remove) a backslash
6389 character to get your parentheses to balance. See L<attributes>.
6391 =item Unterminated compressed integer
6393 (F) An argument to unpack("w",...) was incompatible with the BER
6394 compressed integer format and could not be converted to an integer.
6395 See L<perlfunc/pack>.
6397 =item Unterminated delimiter for here document
6399 (F) This message occurs when a here document label has an initial
6400 quotation mark but the final quotation mark is missing. Perhaps
6409 =item Unterminated \g... pattern in regex; marked by S<<-- HERE> in m/%s/
6411 =item Unterminated \g{...} pattern in regex; marked by S<<-- HERE> in m/%s/
6413 (F) In a regular expression, you had a C<\g> that wasn't followed by a
6414 proper group reference. In the case of C<\g{>, the closing brace is
6415 missing; otherwise the C<\g> must be followed by an integer. Fix the
6418 =item Unterminated <> operator
6420 (F) The lexer saw a left angle bracket in a place where it was expecting
6421 a term, so it's looking for the corresponding right angle bracket, and
6422 not finding it. Chances are you left some needed parentheses out
6423 earlier in the line, and you really meant a "less than".
6425 =item Unterminated verb pattern argument in regex; marked by S<<-- HERE> in
6428 (F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
6429 the pattern with a C<)>. Fix the pattern and retry.
6431 =item Unterminated verb pattern in regex; marked by S<<-- HERE> in m/%s/
6433 (F) You used a pattern of the form C<(*VERB)> but did not terminate
6434 the pattern with a C<)>. Fix the pattern and retry.
6436 =item untie attempted while %d inner references still exist
6438 (W untie) A copy of the object returned from C<tie> (or C<tied>) was
6439 still valid when C<untie> was called.
6441 =item Usage: POSIX::%s(%s)
6443 (F) You called a POSIX function with incorrect arguments.
6444 See L<POSIX/FUNCTIONS> for more information.
6446 =item Usage: Win32::%s(%s)
6448 (F) You called a Win32 function with incorrect arguments.
6449 See L<Win32> for more information.
6451 =item $[ used in %s (did you mean $] ?)
6453 (W syntax) You used C<$[> in a comparison, such as:
6459 You probably meant to use C<$]> instead. C<$[> is the base for indexing
6460 arrays. C<$]> is the Perl version number in decimal.
6462 =item Use "%s" instead of "%s"
6464 (F) The second listed construct is no longer legal. Use the first one
6467 =item Useless assignment to a temporary
6469 (W misc) You assigned to an lvalue subroutine, but what
6470 the subroutine returned was a temporary scalar about to
6471 be discarded, so the assignment had no effect.
6473 =item Useless (?-%s) - don't use /%s modifier in regex; marked by
6474 S<<-- HERE> in m/%s/
6476 (W regexp) You have used an internal modifier such as (?-o) that has no
6477 meaning unless removed from the entire regexp:
6479 if ($string =~ /(?-o)$pattern/o) { ... }
6483 if ($string =~ /$pattern/) { ... }
6485 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6486 discovered. See L<perlre>.
6488 =item Useless localization of %s
6490 (W syntax) The localization of lvalues such as C<local($x=10)> is legal,
6491 but in fact the local() currently has no effect. This may change at
6492 some point in the future, but in the meantime such code is discouraged.
6494 =item Useless (?%s) - use /%s modifier in regex; marked by S<<-- HERE> in
6497 (W regexp) You have used an internal modifier such as (?o) that has no
6498 meaning unless applied to the entire regexp:
6500 if ($string =~ /(?o)$pattern/) { ... }
6504 if ($string =~ /$pattern/o) { ... }
6506 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6507 discovered. See L<perlre>.
6509 =item Useless use of attribute "const"
6511 (W misc) The C<const> attribute has no effect except
6512 on anonymous closure prototypes. You applied it to
6513 a subroutine via L<attributes.pm|attributes>. This is only useful
6514 inside an attribute handler for an anonymous subroutine.
6516 =item Useless use of /d modifier in transliteration operator
6518 (W misc) You have used the /d modifier where the searchlist has the
6519 same length as the replacelist. See L<perlop> for more information
6520 about the /d modifier.
6522 =item Useless use of \E
6524 (W misc) You have a \E in a double-quotish string without a C<\U>,
6525 C<\L> or C<\Q> preceding it.
6527 =item Useless use of greediness modifier '%c' in regex; marked by S<<-- HERE> in m/%s/
6529 (W regexp) You specified something like these:
6534 The C<"?"> and C<"+"> don't have any effect, as they modify whether to
6535 match more or fewer when there is a choice, and by specifying to match
6536 exactly a given numer, there is no room left for a choice.
6538 =item Useless use of %s in void context
6540 (W void) You did something without a side effect in a context that does
6541 nothing with the return value, such as a statement that doesn't return a
6542 value from a block, or the left side of a scalar comma operator. Very
6543 often this points not to stupidity on your part, but a failure of Perl
6544 to parse your program the way you thought it would. For example, you'd
6545 get this if you mixed up your C precedence with Python precedence and
6550 when you meant to say
6552 ($one, $two) = (1, 2);
6554 Another common error is to use ordinary parentheses to construct a list
6555 reference when you should be using square or curly brackets, for
6560 when you should have said
6564 The square brackets explicitly turn a list value into a scalar value,
6565 while parentheses do not. So when a parenthesized list is evaluated in
6566 a scalar context, the comma is treated like C's comma operator, which
6567 throws away the left argument, which is not what you want. See
6568 L<perlref> for more on this.
6570 This warning will not be issued for numerical constants equal to 0 or 1
6571 since they are often used in statements like
6573 1 while sub_with_side_effects();
6575 String constants that would normally evaluate to 0 or 1 are warned
6578 =item Useless use of (?-p) in regex; marked by S<<-- HERE> in m/%s/
6580 (W regexp) The C<p> modifier cannot be turned off once set. Trying to do
6583 =item Useless use of "re" pragma
6585 (W) You did C<use re;> without any arguments. That isn't very useful.
6587 =item Useless use of sort in scalar context
6589 (W void) You used sort in scalar context, as in :
6593 This is not very useful, and perl currently optimizes this away.
6595 =item Useless use of %s with no values
6597 (W syntax) You used the push() or unshift() function with no arguments
6598 apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
6599 usually have any effect on the array, so is completely useless. It's
6600 possible in principle that push(@tied_array) could have some effect
6601 if the array is tied to a class which implements a PUSH method. If so,
6602 you can write it as C<push(@tied_array,())> to avoid this warning.
6604 =item "use" not allowed in expression
6606 (F) The "use" keyword is recognized and executed at compile time, and
6607 returns no useful value. See L<perlmod>.
6609 =item Use of assignment to $[ is deprecated
6611 (D deprecated) The C<$[> variable (index of the first element in an array)
6612 is deprecated. See L<perlvar/"$[">.
6614 =item Use of bare << to mean <<"" is deprecated
6616 (D deprecated) You are now encouraged to use the explicitly quoted
6617 form if you wish to use an empty line as the terminator of the
6620 =item Use of %s for non-UTF-8 locale is wrong. Assuming a UTF-8 locale
6622 (W locale) You are matching a regular expression using locale rules,
6623 and the specified construct was encountered. This construct is only
6624 valid for UTF-8 locales, which the current locale isn't. This doesn't
6625 make sense. Perl will continue, assuming a Unicode (UTF-8) locale, but
6626 the results are likely to be wrong.
6628 =item Use of /c modifier is meaningless in s///
6630 (W regexp) You used the /c modifier in a substitution. The /c
6631 modifier is not presently meaningful in substitutions.
6633 =item Use of /c modifier is meaningless without /g
6635 (W regexp) You used the /c modifier with a regex operand, but didn't
6636 use the /g modifier. Currently, /c is meaningful only when /g is
6637 used. (This may change in the future.)
6639 =item Use of comma-less variable list is deprecated
6641 (D deprecated) The values you give to a format should be
6642 separated by commas, not just aligned on a line.
6644 =item Use of each() on hash after insertion without resetting hash iterator results in undefined behavior
6646 (S internal) The behavior of C<each()> after insertion is undefined;
6647 it may skip items, or visit items more than once. Consider using
6648 C<keys()> instead of C<each()>.
6650 =item Use of := for an empty attribute list is not allowed
6652 (F) The construction C<my $x := 42> used to parse as equivalent to
6653 C<my $x : = 42> (applying an empty attribute list to C<$x>).
6654 This construct was deprecated in 5.12.0, and has now been made a syntax
6655 error, so C<:=> can be reclaimed as a new operator in the future.
6657 If you need an empty attribute list, for example in a code generator, add
6658 a space before the C<=>.
6660 =item Use of freed value in iteration
6662 (F) Perhaps you modified the iterated array within the loop?
6663 This error is typically caused by code like the following:
6666 @a = () for (1,2,@a);
6668 You are not supposed to modify arrays while they are being iterated over.
6669 For speed and efficiency reasons, Perl internally does not do full
6670 reference-counting of iterated items, hence deleting such an item in the
6671 middle of an iteration causes Perl to see a freed value.
6673 =item Use of *glob{FILEHANDLE} is deprecated
6675 (D deprecated) You are now encouraged to use the shorter *glob{IO} form
6676 to access the filehandle slot within a typeglob.
6678 =item Use of /g modifier is meaningless in split
6680 (W regexp) You used the /g modifier on the pattern for a C<split>
6681 operator. Since C<split> always tries to match the pattern
6682 repeatedly, the C</g> has no effect.
6684 =item Use of "goto" to jump into a construct is deprecated
6686 (D deprecated) Using C<goto> to jump from an outer scope into an inner
6687 scope is deprecated and should be avoided.
6689 =item Use of inherited AUTOLOAD for non-method %s() is deprecated
6691 (D deprecated) As an (ahem) accidental feature, C<AUTOLOAD>
6692 subroutines are looked up as methods (using the C<@ISA> hierarchy)
6693 even when the subroutines to be autoloaded were called as plain
6694 functions (e.g. C<Foo::bar()>), not as methods (e.g. C<< Foo->bar() >> or
6695 C<< $obj->bar() >>).
6697 This bug will be rectified in future by using method lookup only for
6698 methods' C<AUTOLOAD>s. However, there is a significant base of existing
6699 code that may be using the old behavior. So, as an interim step, Perl
6700 currently issues an optional warning when non-methods use inherited
6703 The simple rule is: Inheritance will not work when autoloading
6704 non-methods. The simple fix for old code is: In any module that used
6705 to depend on inheriting C<AUTOLOAD> for non-methods from a base class
6706 named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
6709 In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
6710 you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
6711 C<use AutoLoader 'AUTOLOAD';>.
6713 =item Use of %s in printf format not supported
6715 (F) You attempted to use a feature of printf that is accessible from
6716 only C. This usually means there's a better way to do it in Perl.
6718 =item Use of %s is deprecated
6720 (D deprecated) The construct indicated is no longer recommended for use,
6721 generally because there's a better way to do it, and also because the
6722 old way has bad side effects.
6724 =item Use of literal control characters in variable names is deprecated
6726 =item Use of literal non-graphic characters in variable names is deprecated
6728 (D deprecated) Using literal non-graphic (including control)
6729 characters in the source to refer to the ^FOO variables, like C<$^X> and
6730 C<${^GLOBAL_PHASE}> is now deprecated. (We use C<^X> and C<^G> here for
6731 legibility. They actually represent the non-printable control
6732 characters, code points 0x18 and 0x07, respectively; C<^A> would mean
6733 the control character whose code point is 0x01.) This only affects
6734 code like C<$\cT>, where C<\cT> is a control in the source code; C<${"\cT"}> and
6735 C<$^T> remain valid. Things that are non-controls and also not graphic
6736 are NO-BREAK SPACE and SOFT HYPHEN, which were previously only allowed
6737 for historical reasons.
6739 =item Use of -l on filehandle%s
6741 (W io) A filehandle represents an opened file, and when you opened the file
6742 it already went past any symlink you are presumably trying to look for.
6743 The operation returned C<undef>. Use a filename instead.
6745 =item Use of %s on a handle without * is deprecated
6747 (D deprecated) You used C<tie>, C<tied> or C<untie> on a scalar but that scalar
6748 happens to hold a typeglob, which means its filehandle will be tied. If
6749 you mean to tie a handle, use an explicit * as in C<tie *$handle>.
6751 This was a long-standing bug that was removed in Perl 5.16, as there was
6752 no way to tie the scalar itself when it held a typeglob, and no way to
6753 untie a scalar that had had a typeglob assigned to it. If you see this
6754 message, you must be using an older version.
6756 =item Use of reference "%s" as array index
6758 (W misc) You tried to use a reference as an array index; this probably
6759 isn't what you mean, because references in numerical context tend
6760 to be huge numbers, and so usually indicates programmer error.
6762 If you really do mean it, explicitly numify your reference, like so:
6763 C<$array[0+$ref]>. This warning is not given for overloaded objects,
6764 however, because you can overload the numification and stringification
6765 operators and then you presumably know what you are doing.
6767 =item Use of state $_ is experimental
6769 (S experimental::lexical_topic) Lexical $_ is an experimental feature and
6770 its behavior may change or even be removed in any future release of perl.
6771 See the explanation under L<perlvar/$_>.
6773 =item Use of tainted arguments in %s is deprecated
6775 (W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
6776 arguments and at least one of them is tainted. This used to be allowed
6777 but will become a fatal error in a future version of perl. Untaint your
6778 arguments. See L<perlsec>.
6780 =item Use of uninitialized value%s
6782 (W uninitialized) An undefined value was used as if it were already
6783 defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
6784 To suppress this warning assign a defined value to your variables.
6786 To help you figure out what was undefined, perl will try to tell you
6787 the name of the variable (if any) that was undefined. In some cases
6788 it cannot do this, so it also tells you what operation you used the
6789 undefined value in. Note, however, that perl optimizes your program
6790 and the operation displayed in the warning may not necessarily appear
6791 literally in your program. For example, C<"that $foo"> is usually
6792 optimized into C<"that " . $foo>, and the warning will refer to the
6793 C<concatenation (.)> operator, even though there is no C<.> in
6796 =item "use re 'strict'" is experimental
6798 (S experimental::re_strict) The things that are different when a regular
6799 expression pattern is compiled under C<'strict'> are subject to change
6800 in future Perl releases in incompatible ways. This means that a pattern
6801 that compiles today may not in a future Perl release. This warning is
6802 to alert you to that risk.
6804 =item Use \x{...} for more than two hex characters in regex; marked by
6805 S<<-- HERE> in m/%s/
6807 (F) In a regular expression, you said something like
6811 Perl isn't sure if you meant this
6815 or if you meant this
6817 (?[ [ \x{BE} E F ] ])
6819 You need to add either braces or blanks to disambiguate.
6821 =item Using just the first character returned by \N{} in character class in
6822 regex; marked by S<<-- HERE> in m/%s/
6824 (W regexp) Named Unicode character escapes C<(\N{...})> may return
6825 a multi-character sequence. Even though a character class is
6826 supposed to match just one character of input, perl will match
6827 the whole thing correctly, except when the class is inverted
6828 (C<[^...]>), or the escape is the beginning or final end point of
6829 a range. For these, what should happen isn't clear at all. In
6830 these circumstances, Perl discards all but the first character
6831 of the returned sequence, which is not likely what you want.
6833 =item Using /u for '%s' instead of /%s in regex; marked by S<<-- HERE> in m/%s/
6835 (W regexp) You used a Unicode boundary (C<\b{...}> or C<\B{...}>) in a
6836 portion of a regular expression where the character set modifiers C</a>
6837 or C</aa> are in effect. These two modifiers indicate an ASCII
6838 interpretation, and this doesn't make sense for a Unicode defintion.
6839 The generated regular expression will compile so that the boundary uses
6840 all of Unicode. No other portion of the regular expression is affected.
6842 =item Using !~ with %s doesn't make sense
6844 (F) Using the C<!~> operator with C<s///r>, C<tr///r> or C<y///r> is
6845 currently reserved for future use, as the exact behavior has not
6846 been decided. (Simply returning the boolean opposite of the
6847 modified string is usually not particularly useful.)
6849 =item UTF-16 surrogate U+%X
6851 (S surrogate) You had a UTF-16 surrogate in a context where they are
6852 not considered acceptable. These code points, between U+D800 and
6853 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6854 internally allows all unsigned integer code points (up to the size limit
6855 available on your platform), including surrogates. But these can cause
6856 problems when being input or output, which is likely where this message
6857 came from. If you really really know what you are doing you can turn
6858 off this warning by C<no warnings 'surrogate';>.
6860 =item Value of %s can be "0"; test with defined()
6862 (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
6863 C<each()>, or C<readdir()> as a boolean value. Each of these constructs
6864 can return a value of "0"; that would make the conditional expression
6865 false, which is probably not what you intended. When using these
6866 constructs in conditional expressions, test their values with the
6867 C<defined> operator.
6869 =item Value of CLI symbol "%s" too long
6871 (W misc) A warning peculiar to VMS. Perl tried to read the value of an
6872 %ENV element from a CLI symbol table, and found a resultant string
6873 longer than 1024 characters. The return value has been truncated to
6876 =item Variable "%s" is not available
6878 (W closure) During compilation, an inner named subroutine or eval is
6879 attempting to capture an outer lexical that is not currently available.
6880 This can happen for one of two reasons. First, the outer lexical may be
6881 declared in an outer anonymous subroutine that has not yet been created.
6882 (Remember that named subs are created at compile time, while anonymous
6883 subs are created at run-time.) For example,
6885 sub { my $a; sub f { $a } }
6887 At the time that f is created, it can't capture the current value of $a,
6888 since the anonymous subroutine hasn't been created yet. Conversely,
6889 the following won't give a warning since the anonymous subroutine has by
6890 now been created and is live:
6892 sub { my $a; eval 'sub f { $a }' }->();
6894 The second situation is caused by an eval accessing a variable that has
6895 gone out of scope, for example,
6903 Here, when the '$a' in the eval is being compiled, f() is not currently
6904 being executed, so its $a is not available for capture.
6906 =item Variable "%s" is not imported%s
6908 (S misc) With "use strict" in effect, you referred to a global variable
6909 that you apparently thought was imported from another module, because
6910 something else of the same name (usually a subroutine) is exported by
6911 that module. It usually means you put the wrong funny character on the
6912 front of your variable.
6914 =item Variable length lookbehind not implemented in regex m/%s/
6916 (F) Lookbehind is allowed only for subexpressions whose length is fixed and
6917 known at compile time. For positive lookbehind, you can use the C<\K>
6918 regex construct as a way to get the equivalent functionality. See
6919 L<perlre/(?<=pattern) \K>.
6921 There are non-obvious Unicode rules under C</i> that can match variably,
6922 but which you might not think could. For example, the substring C<"ss">
6923 can match the single character LATIN SMALL LETTER SHARP S. There are
6924 other sequences of ASCII characters that can match single ligature
6925 characters, such as LATIN SMALL LIGATURE FFI matching C<qr/ffi/i>.
6926 Starting in Perl v5.16, if you only care about ASCII matches, adding the
6927 C</aa> modifier to the regex will exclude all these non-obvious matches,
6928 thus getting rid of this message. You can also say C<S<use re qw(/aa)>>
6929 to apply C</aa> to all regular expressions compiled within its scope.
6932 =item "%s" variable %s masks earlier declaration in same %s
6934 (W misc) A "my", "our" or "state" variable has been redeclared in the
6935 current scope or statement, effectively eliminating all access to the
6936 previous instance. This is almost always a typographical error. Note
6937 that the earlier variable will still exist until the end of the scope
6938 or until all closure references to it are destroyed.
6940 =item Variable syntax
6942 (A) You've accidentally run your script through B<csh> instead
6943 of Perl. Check the #! line, or manually feed your script into
6946 =item Variable "%s" will not stay shared
6948 (W closure) An inner (nested) I<named> subroutine is referencing a
6949 lexical variable defined in an outer named subroutine.
6951 When the inner subroutine is called, it will see the value of
6952 the outer subroutine's variable as it was before and during the *first*
6953 call to the outer subroutine; in this case, after the first call to the
6954 outer subroutine is complete, the inner and outer subroutines will no
6955 longer share a common value for the variable. In other words, the
6956 variable will no longer be shared.
6958 This problem can usually be solved by making the inner subroutine
6959 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
6960 reference variables in outer subroutines are created, they
6961 are automatically rebound to the current values of such variables.
6963 =item vector argument not supported with alpha versions
6965 (S printf) The %vd (s)printf format does not support version objects
6968 =item Verb pattern '%s' has a mandatory argument in regex; marked by
6969 S<<-- HERE> in m/%s/
6971 (F) You used a verb pattern that requires an argument. Supply an
6972 argument or check that you are using the right verb.
6974 =item Verb pattern '%s' may not have an argument in regex; marked by
6975 S<<-- HERE> in m/%s/
6977 (F) You used a verb pattern that is not allowed an argument. Remove the
6978 argument or check that you are using the right verb.
6980 =item Version number must be a constant number
6982 (P) The attempt to translate a C<use Module n.n LIST> statement into
6983 its equivalent C<BEGIN> block found an internal inconsistency with
6986 =item Version string '%s' contains invalid data; ignoring: '%s'
6988 (W misc) The version string contains invalid characters at the end, which
6991 =item Warning: something's wrong
6993 (W) You passed warn() an empty string (the equivalent of C<warn "">) or
6994 you called it with no args and C<$@> was empty.
6996 =item Warning: unable to close filehandle %s properly
6998 (S) The implicit close() done by an open() got an error indication on
6999 the close(). This usually indicates your file system ran out of disk
7002 =item Warning: unable to close filehandle properly: %s
7004 =item Warning: unable to close filehandle %s properly: %s
7006 (S io) An error occurred when Perl implicitly closed a filehandle. This
7007 usually indicates your file system ran out of disk space.
7009 =item Warning: Use of "%s" without parentheses is ambiguous
7011 (S ambiguous) You wrote a unary operator followed by something that
7012 looks like a binary operator that could also have been interpreted as a
7013 term or unary operator. For instance, if you know that the rand
7014 function has a default argument of 1.0, and you write
7018 you may THINK you wrote the same thing as
7022 but in actual fact, you got
7026 So put in parentheses to say what you really mean.
7028 =item when is experimental
7030 (S experimental::smartmatch) C<when> depends on smartmatch, which is
7031 experimental. Additionally, it has several special cases that may
7032 not be immediately obvious, and their behavior may change or
7033 even be removed in any future release of perl. See the explanation
7034 under L<perlsyn/Experimental Details on given and when>.
7036 =item Wide character in %s
7038 (S utf8) Perl met a wide character (>255) when it wasn't expecting
7039 one. This warning is by default on for I/O (like print). The easiest
7040 way to quiet this warning is simply to add the C<:utf8> layer to the
7041 output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
7042 warning is to add C<no warnings 'utf8';> but that is often closer to
7043 cheating. In general, you are supposed to explicitly mark the
7044 filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
7046 =item Wide character (U+%X) in %s
7048 (W locale) While in a single-byte locale (I<i.e.>, a non-UTF-8
7049 one), a multi-byte character was encountered. Perl considers this
7050 character to be the specified Unicode code point. Combining non-UTF-8
7051 locales and Unicode is dangerous. Almost certainly some characters
7052 will have two different representations. For example, in the ISO 8859-7
7053 (Greek) locale, the code point 0xC3 represents a Capital Gamma. But so
7054 also does 0x393. This will make string comparisons unreliable.
7056 You likely need to figure out how this multi-byte character got mixed up
7057 with your single-byte locale (or perhaps you thought you had a UTF-8
7058 locale, but Perl disagrees).
7060 =item %s() with negative argument
7062 (S misc) Certain operations make no sense with negative arguments.
7063 Warning is given and the operation is not done.
7065 =item Within []-length '%c' not allowed
7067 (F) The count in the (un)pack template may be replaced by C<[TEMPLATE]>
7068 only if C<TEMPLATE> always matches the same amount of packed bytes that
7069 can be determined from the template alone. This is not possible if
7070 it contains any of the codes @, /, U, u, w or a *-length. Redesign
7073 =item write() on closed filehandle %s
7075 (W closed) The filehandle you're writing to got itself closed sometime
7076 before now. Check your control flow.
7078 =item %s "\x%X" does not map to Unicode
7080 (S utf8) When reading in different encodings, Perl tries to
7081 map everything into Unicode characters. The bytes you read
7082 in are not legal in this encoding. For example
7084 utf8 "\xE4" does not map to Unicode
7086 if you try to read in the a-diaereses Latin-1 as UTF-8.
7088 =item 'X' outside of string
7090 (F) You had a (un)pack template that specified a relative position before
7091 the beginning of the string being (un)packed. See L<perlfunc/pack>.
7093 =item 'x' outside of string in unpack
7095 (F) You had a pack template that specified a relative position after
7096 the end of the string being unpacked. See L<perlfunc/pack>.
7098 =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
7100 (F) And you probably never will, because you probably don't have the
7101 sources to your kernel, and your vendor probably doesn't give a rip
7102 about what you want. Your best bet is to put a setuid C wrapper around
7105 =item You need to quote "%s"
7107 (W syntax) You assigned a bareword as a signal handler name.
7108 Unfortunately, you already have a subroutine of that name declared,
7109 which means that Perl 5 will try to call the subroutine when the
7110 assignment is executed, which is probably not what you want. (If it IS
7111 what you want, put an & in front.)
7113 =item Your random numbers are not that random
7115 (F) When trying to initialize the random seed for hashes, Perl could
7116 not get any randomness out of your system. This usually indicates
7117 Something Very Wrong.
7119 =item Zero length \N{} in regex; marked by S<<-- HERE> in m/%s/
7121 (F) Named Unicode character escapes (C<\N{...}>) may return a zero-length
7122 sequence. Such an escape was used in an extended character class, i.e.
7123 C<(?[...])>, which is not permitted. Check that the correct escape has
7124 been used, and the correct charnames handler is in scope. The S<<-- HERE>
7125 shows whereabouts in the regular expression the problem was discovered.
7131 L<warnings>, L<diagnostics>.