3 perldiag - various Perl diagnostics
7 These messages are classified as follows (listed in increasing order of
10 (W) A warning (optional).
11 (D) A deprecation (enabled by default).
12 (S) A severe warning (enabled by default).
13 (F) A fatal error (trappable).
14 (P) An internal error you should never see (trappable).
15 (X) A very fatal error (nontrappable).
16 (A) An alien error message (not generated by Perl).
18 The majority of messages from the first three classifications above
19 (W, D & S) can be controlled using the C<warnings> pragma.
21 If a message can be controlled by the C<warnings> pragma, its warning
22 category is included with the classification letter in the description
23 below. E.g. C<(W closed)> means a warning in the C<closed> category.
25 Optional warnings are enabled by using the C<warnings> pragma or the B<-w>
26 and B<-W> switches. Warnings may be captured by setting C<$SIG{__WARN__}>
27 to a reference to a routine that will be called on each warning instead
28 of printing it. See L<perlvar>.
30 Severe warnings are always enabled, unless they are explicitly disabled
31 with the C<warnings> pragma or the B<-X> switch.
33 Trappable errors may be trapped using the eval operator. See
34 L<perlfunc/eval>. In almost all cases, warnings may be selectively
35 disabled or promoted to fatal errors using the C<warnings> pragma.
38 The messages are in alphabetical order, without regard to upper or
39 lower-case. Some of these messages are generic. Spots that vary are
40 denoted with a %s or other printf-style escape. These escapes are
41 ignored by the alphabetical order, as are all characters other than
42 letters. To look up your message, just ignore anything that is not a
47 =item accept() on closed socket %s
49 (W closed) You tried to do an accept on a closed socket. Did you forget
50 to check the return value of your socket() call? See
53 =item Aliasing via reference is experimental
55 (S experimental::refaliasing) This warning is emitted if you use
56 a reference constructor on the left-hand side of an assignment to
57 alias one variable to another. Simply suppress the warning if you
58 want to use the feature, but know that in doing so you are taking
59 the risk of using an experimental feature which may change or be
60 removed in a future Perl version:
62 no warnings "experimental::refaliasing";
63 use feature "refaliasing";
66 =item Allocation too large: %x
68 (X) You can't allocate more than 64K on an MS-DOS machine.
70 =item '%c' allowed only after types %s in %s
72 (F) The modifiers '!', '<' and '>' are allowed in pack() or unpack() only
73 after certain types. See L<perlfunc/pack>.
75 =item alpha->numify() is lossy
77 (W numeric) An alpha version can not be numified without losing
80 =item Ambiguous call resolved as CORE::%s(), qualify as such or use &
82 (W ambiguous) A subroutine you have declared has the same name as a Perl
83 keyword, and you have used the name without qualification for calling
84 one or the other. Perl decided to call the builtin because the
85 subroutine is not imported.
87 To force interpretation as a subroutine call, either put an ampersand
88 before the subroutine name, or qualify the name with its package.
89 Alternatively, you can import the subroutine (or pretend that it's
90 imported with the C<use subs> pragma).
92 To silently interpret it as the Perl operator, use the C<CORE::> prefix
93 on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
94 to be an object method (see L<perlsub/"Subroutine Attributes"> or
97 =item Ambiguous range in transliteration operator
99 (F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
100 all. To include a C<-> character in a transliteration, put it either
101 first or last. (In the past, C<tr/a-z-0//> was synonymous with
102 C<tr/a-y//>, which was probably not what you would have expected.)
104 =item Ambiguous use of %s resolved as %s
106 (S ambiguous) You said something that may not be interpreted the way
107 you thought. Normally it's pretty easy to disambiguate it by supplying
108 a missing quote, operator, parenthesis pair or declaration.
110 =item Ambiguous use of -%s resolved as -&%s()
112 (S ambiguous) You wrote something like C<-foo>, which might be the
113 string C<"-foo">, or a call to the function C<foo>, negated. If you meant
114 the string, just write C<"-foo">. If you meant the function call,
117 =item Ambiguous use of %c resolved as operator %c
119 (S ambiguous) C<%>, C<&>, and C<*> are both infix operators (modulus,
120 bitwise and, and multiplication) I<and> initial special characters
121 (denoting hashes, subroutines and typeglobs), and you said something
122 like C<*foo * foo> that might be interpreted as either of them. We
123 assumed you meant the infix operator, but please try to make it more
124 clear -- in the example given, you might write C<*foo * foo()> if you
125 really meant to multiply a glob by the result of calling a function.
127 =item Ambiguous use of %c{%s} resolved to %c%s
129 (W ambiguous) You wrote something like C<@{foo}>, which might be
130 asking for the variable C<@foo>, or it might be calling a function
131 named foo, and dereferencing it as an array reference. If you wanted
132 the variable, you can just write C<@foo>. If you wanted to call the
133 function, write C<@{foo()}> ... or you could just not have a variable
134 and a function with the same name, and save yourself a lot of trouble.
136 =item Ambiguous use of %c{%s[...]} resolved to %c%s[...]
138 =item Ambiguous use of %c{%s{...}} resolved to %c%s{...}
140 (W ambiguous) You wrote something like C<${foo[2]}> (where foo represents
141 the name of a Perl keyword), which might be looking for element number
142 2 of the array named C<@foo>, in which case please write C<$foo[2]>, or you
143 might have meant to pass an anonymous arrayref to the function named
144 foo, and then do a scalar deref on the value it returns. If you meant
145 that, write C<${foo([2])}>.
147 In regular expressions, the C<${foo[2]}> syntax is sometimes necessary
148 to disambiguate between array subscripts and character classes.
149 C</$length[2345]/>, for instance, will be interpreted as C<$length> followed
150 by the character class C<[2345]>. If an array subscript is what you
151 want, you can avoid the warning by changing C</${length[2345]}/> to the
152 unsightly C</${\$length[2345]}/>, by renaming your array to something
153 that does not coincide with a built-in keyword, or by simply turning
154 off warnings with C<no warnings 'ambiguous';>.
156 =item '|' and '<' may not both be specified on command line
158 (F) An error peculiar to VMS. Perl does its own command line
159 redirection, and found that STDIN was a pipe, and that you also tried to
160 redirect STDIN using '<'. Only one STDIN stream to a customer, please.
162 =item '|' and '>' may not both be specified on command line
164 (F) An error peculiar to VMS. Perl does its own command line
165 redirection, and thinks you tried to redirect stdout both to a file and
166 into a pipe to another command. You need to choose one or the other,
167 though nothing's stopping you from piping into a program or Perl script
168 which 'splits' output into two streams, such as
170 open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
177 =item Applying %s to %s will act on scalar(%s)
179 (W misc) The pattern match (C<//>), substitution (C<s///>), and
180 transliteration (C<tr///>) operators work on scalar values. If you apply
181 one of them to an array or a hash, it will convert the array or hash to
182 a scalar value (the length of an array, or the population info of a
183 hash) and then work on that scalar value. This is probably not what
184 you meant to do. See L<perlfunc/grep> and L<perlfunc/map> for
187 =item Arg too short for msgsnd
189 (F) msgsnd() requires a string at least as long as sizeof(long).
191 =item Argument "%s" isn't numeric%s
193 (W numeric) The indicated string was fed as an argument to an operator
194 that expected a numeric value instead. If you're fortunate the message
195 will identify which operator was so unfortunate.
197 Note that for the C<Inf> and C<NaN> (infinity and not-a-number) the
198 definition of "numeric" is somewhat unusual: the strings themselves
199 (like "Inf") are considered numeric, and anything following them is
200 considered non-numeric.
202 =item Argument list not closed for PerlIO layer "%s"
204 (W layer) When pushing a layer with arguments onto the Perl I/O
205 system you forgot the ) that closes the argument list. (Layers
206 take care of transforming data between external and internal
207 representations.) Perl stopped parsing the layer list at this
208 point and did not attempt to push this layer. If your program
209 didn't explicitly request the failing operation, it may be the
210 result of the value of the environment variable PERLIO.
212 =item Argument "%s" treated as 0 in increment (++)
214 (W numeric) The indicated string was fed as an argument to the C<++>
215 operator which expects either a number or a string matching
216 C</^[a-zA-Z]*[0-9]*\z/>. See L<perlop/Auto-increment and
217 Auto-decrement> for details.
219 =item Array passed to stat will be coerced to a scalar%s
221 (W syntax) You called stat() on an array, but the array will be
222 coerced to a scalar - the number of elements in the array.
224 =item assertion botched: %s
226 (X) The malloc package that comes with Perl had an internal failure.
228 =item Assertion %s failed: file "%s", line %d
230 (X) A general assertion failed. The file in question must be examined.
232 =item Assigned value is not a reference
234 (F) You tried to assign something that was not a reference to an lvalue
235 reference (e.g., C<\$x = $y>). If you meant to make $x an alias to $y, use
238 =item Assigned value is not %s reference
240 (F) You tried to assign a reference to a reference constructor, but the
241 two references were not of the same type. You cannot alias a scalar to
242 an array, or an array to a hash; the two types must match.
247 \$x = $y; # error; did you mean \$y?
249 =item Assigning non-zero to $[ is no longer possible
251 (F) When the "array_base" feature is disabled (e.g., under C<use v5.16;>)
252 the special variable C<$[>, which is deprecated, is now a fixed zero value.
254 =item Assignment to both a list and a scalar
256 (F) If you assign to a conditional operator, the 2nd and 3rd arguments
257 must either both be scalars or both be lists. Otherwise Perl won't
258 know which context to supply to the right side.
260 =item Assuming NOT a POSIX class since %s in regex; marked by S<<-- HERE> in m/%s/
262 (W regexp) You had something like these:
267 They look like they might have been meant to be the POSIX classes
268 C<[:alnum:]> or C<[:digit:]>. If so, they should be written:
273 Since these aren't legal POSIX class specifications, but are legal
274 bracketed character classes, Perl treats them as the latter. In the
275 first example, it matches the characters C<":">, C<"[">, C<"a">, C<"l">,
276 C<"m">, C<"n">, and C<"u">.
278 If these weren't meant to be POSIX classes, this warning message is
279 spurious, and can be suppressed by reordering things, such as
287 =item <> at require-statement should be quotes
289 (F) You wrote C<< require <file> >> when you should have written
292 =item Attempt to access disallowed key '%s' in a restricted hash
294 (F) The failing code has attempted to get or set a key which is not in
295 the current set of allowed keys of a restricted hash.
297 =item Attempt to bless into a freed package
299 (F) You wrote C<bless $foo> with one argument after somehow causing
300 the current package to be freed. Perl cannot figure out what to
301 do, so it throws up in hands in despair.
303 =item Attempt to bless into a reference
305 (F) The CLASSNAME argument to the bless() operator is expected to be
306 the name of the package to bless the resulting object into. You've
307 supplied instead a reference to something: perhaps you wrote
313 bless $self, ref($proto) || $proto;
315 If you actually want to bless into the stringified version
316 of the reference supplied, you need to stringify it yourself, for
319 bless $self, "$proto";
321 =item Attempt to clear deleted array
323 (S debugging) An array was assigned to when it was being freed.
324 Freed values are not supposed to be visible to Perl code. This
325 can also happen if XS code calls C<av_clear> from a custom magic
326 callback on the array.
328 =item Attempt to delete disallowed key '%s' from a restricted hash
330 (F) The failing code attempted to delete from a restricted hash a key
331 which is not in its key set.
333 =item Attempt to delete readonly key '%s' from a restricted hash
335 (F) The failing code attempted to delete a key whose value has been
336 declared readonly from a restricted hash.
338 =item Attempt to free non-arena SV: 0x%x
340 (S internal) All SV objects are supposed to be allocated from arenas
341 that will be garbage collected on exit. An SV was discovered to be
342 outside any of those arenas.
344 =item Attempt to free nonexistent shared string '%s'%s
346 (S internal) Perl maintains a reference-counted internal table of
347 strings to optimize the storage and access of hash keys and other
348 strings. This indicates someone tried to decrement the reference count
349 of a string that can no longer be found in the table.
351 =item Attempt to free temp prematurely: SV 0x%x
353 (S debugging) Mortalized values are supposed to be freed by the
354 free_tmps() routine. This indicates that something else is freeing the
355 SV before the free_tmps() routine gets a chance, which means that the
356 free_tmps() routine will be freeing an unreferenced scalar when it does
359 =item Attempt to free unreferenced glob pointers
361 (S internal) The reference counts got screwed up on symbol aliases.
363 =item Attempt to free unreferenced scalar: SV 0x%x
365 (S internal) Perl went to decrement the reference count of a scalar to
366 see if it would go to 0, and discovered that it had already gone to 0
367 earlier, and should have been freed, and in fact, probably was freed.
368 This could indicate that SvREFCNT_dec() was called too many times, or
369 that SvREFCNT_inc() was called too few times, or that the SV was
370 mortalized when it shouldn't have been, or that memory has been
373 =item Attempt to pack pointer to temporary value
375 (W pack) You tried to pass a temporary value (like the result of a
376 function, or a computed expression) to the "p" pack() template. This
377 means the result contains a pointer to a location that could become
378 invalid anytime, even before the end of the current statement. Use
379 literals or global values as arguments to the "p" pack() template to
382 =item Attempt to reload %s aborted.
384 (F) You tried to load a file with C<use> or C<require> that failed to
385 compile once already. Perl will not try to compile this file again
386 unless you delete its entry from %INC. See L<perlfunc/require> and
389 =item Attempt to set length of freed array
391 (W misc) You tried to set the length of an array which has
392 been freed. You can do this by storing a reference to the
393 scalar representing the last index of an array and later
394 assigning through that reference. For example
396 $r = do {my @a; \$#a};
399 =item Attempt to use reference as lvalue in substr
401 (W substr) You supplied a reference as the first argument to substr()
402 used as an lvalue, which is pretty strange. Perhaps you forgot to
403 dereference it first. See L<perlfunc/substr>.
405 =item Attribute "locked" is deprecated
407 (D deprecated) You have used the attributes pragma to modify the
408 "locked" attribute on a code reference. The :locked attribute is
409 obsolete, has had no effect since 5005 threads were removed, and
410 will be removed in a future release of Perl 5.
412 =item Attribute prototype(%s) discards earlier prototype attribute in same sub
414 (W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
415 example. Since each sub can only have one prototype, the earlier
416 declaration(s) are discarded while the last one is applied.
418 =item Attribute "unique" is deprecated
420 (D deprecated) You have used the attributes pragma to modify
421 the "unique" attribute on an array, hash or scalar reference.
422 The :unique attribute has had no effect since Perl 5.8.8, and
423 will be removed in a future release of Perl 5.
425 =item av_reify called on tied array
427 (S debugging) This indicates that something went wrong and Perl got I<very>
428 confused about C<@_> or C<@DB::args> being tied.
430 =item Bad arg length for %s, is %u, should be %d
432 (F) You passed a buffer of the wrong size to one of msgctl(), semctl()
433 or shmctl(). In C parlance, the correct sizes are, respectively,
434 S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
435 S<sizeof(struct shmid_ds *)>.
437 =item Bad evalled substitution pattern
439 (F) You've used the C</e> switch to evaluate the replacement for a
440 substitution, but perl found a syntax error in the code to evaluate,
441 most likely an unexpected right brace '}'.
443 =item Bad filehandle: %s
445 (F) A symbol was passed to something wanting a filehandle, but the
446 symbol has no filehandle associated with it. Perhaps you didn't do an
447 open(), or did it in another package.
449 =item Bad free() ignored
451 (S malloc) An internal routine called free() on something that had never
452 been malloc()ed in the first place. Mandatory, but can be disabled by
453 setting environment variable C<PERL_BADFREE> to 0.
455 This message can be seen quite often with DB_File on systems with "hard"
456 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
457 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
461 (P) One of the internal hash routines was passed a null HV pointer.
463 =item Badly placed ()'s
465 (A) You've accidentally run your script through B<csh> instead
466 of Perl. Check the #! line, or manually feed your script into
469 =item Bad name after %s
471 (F) You started to name a symbol by using a package prefix, and then
472 didn't finish the symbol. In particular, you can't interpolate outside
481 $sym = "mypack::$var";
483 =item Bad plugin affecting keyword '%s'
485 (F) An extension using the keyword plugin mechanism violated the
488 =item Bad realloc() ignored
490 (S malloc) An internal routine called realloc() on something that
491 had never been malloc()ed in the first place. Mandatory, but can
492 be disabled by setting the environment variable C<PERL_BADFREE> to 1.
494 =item Bad symbol for array
496 (P) An internal request asked to add an array entry to something that
497 wasn't a symbol table entry.
499 =item Bad symbol for dirhandle
501 (P) An internal request asked to add a dirhandle entry to something
502 that wasn't a symbol table entry.
504 =item Bad symbol for filehandle
506 (P) An internal request asked to add a filehandle entry to something
507 that wasn't a symbol table entry.
509 =item Bad symbol for hash
511 (P) An internal request asked to add a hash entry to something that
512 wasn't a symbol table entry.
514 =item Bad symbol for scalar
516 (P) An internal request asked to add a scalar entry to something that
517 wasn't a symbol table entry.
519 =item Bareword found in conditional
521 (W bareword) The compiler found a bareword where it expected a
522 conditional, which often indicates that an || or && was parsed as part
523 of the last argument of the previous construct, for example:
527 It may also indicate a misspelled constant that has been interpreted as
530 use constant TYPO => 1;
531 if (TYOP) { print "foo" }
533 The C<strict> pragma is useful in avoiding such errors.
535 =item Bareword in require contains "%s"
537 =item Bareword in require maps to disallowed filename "%s"
539 =item Bareword in require maps to empty filename
541 (F) The bareword form of require has been invoked with a filename which could
542 not have been generated by a valid bareword permitted by the parser. You
543 shouldn't be able to get this error from Perl code, but XS code may throw it
544 if it passes an invalid module name to C<Perl_load_module>.
546 =item Bareword in require must not start with a double-colon: "%s"
548 (F) In C<require Bare::Word>, the bareword is not allowed to start with a
549 double-colon. Write C<require ::Foo::Bar> as C<require Foo::Bar> instead.
551 =item Bareword "%s" not allowed while "strict subs" in use
553 (F) With "strict subs" in use, a bareword is only allowed as a
554 subroutine identifier, in curly brackets or to the left of the "=>"
555 symbol. Perhaps you need to predeclare a subroutine?
557 =item Bareword "%s" refers to nonexistent package
559 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
560 compiler saw no other uses of that namespace before that point. Perhaps
561 you need to predeclare a package?
563 =item BEGIN failed--compilation aborted
565 (F) An untrapped exception was raised while executing a BEGIN
566 subroutine. Compilation stops immediately and the interpreter is
569 =item BEGIN not safe after errors--compilation aborted
571 (F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
572 implies a C<BEGIN {}>) after one or more compilation errors had already
573 occurred. Since the intended environment for the C<BEGIN {}> could not
574 be guaranteed (due to the errors), and since subsequent code likely
575 depends on its correct operation, Perl just gave up.
577 =item \%d better written as $%d
579 (W syntax) Outside of patterns, backreferences live on as variables.
580 The use of backslashes is grandfathered on the right-hand side of a
581 substitution, but stylistically it's better to use the variable form
582 because other Perl programmers will expect it, and it works better if
583 there are more than 9 backreferences.
585 =item Binary number > 0b11111111111111111111111111111111 non-portable
587 (W portable) The binary number you specified is larger than 2**32-1
588 (4294967295) and therefore non-portable between systems. See
589 L<perlport> for more on portability concerns.
591 =item bind() on closed socket %s
593 (W closed) You tried to do a bind on a closed socket. Did you forget to
594 check the return value of your socket() call? See L<perlfunc/bind>.
596 =item binmode() on closed filehandle %s
598 (W unopened) You tried binmode() on a filehandle that was never opened.
599 Check your control flow and number of arguments.
601 =item Bit vector size > 32 non-portable
603 (W portable) Using bit vector sizes larger than 32 is non-portable.
605 =item Bizarre copy of %s
607 (P) Perl detected an attempt to copy an internal value that is not
610 =item Bizarre SvTYPE [%d]
612 (P) When starting a new thread or returning values from a thread, Perl
613 encountered an invalid data type.
615 =item Both or neither range ends should be Unicode in regex; marked by
618 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
620 In a bracketed character class in a regular expression pattern, you
621 had a range which has exactly one end of it specified using C<\N{}>, and
622 the other end is specified using a non-portable mechanism. Perl treats
623 the range as a Unicode range, that is, all the characters in it are
624 considered to be the Unicode characters, and which may be different code
625 points on some platforms Perl runs on. For example, C<[\N{U+06}-\x08]>
626 is treated as if you had instead said C<[\N{U+06}-\N{U+08}]>, that is it
627 matches the characters whose code points in Unicode are 6, 7, and 8.
628 But that C<\x08> might indicate that you meant something different, so
629 the warning gets raised.
631 =item Buffer overflow in prime_env_iter: %s
633 (W internal) A warning peculiar to VMS. While Perl was preparing to
634 iterate over %ENV, it encountered a logical name or symbol definition
635 which was too long, so it was truncated to the string shown.
637 =item Callback called exit
639 (F) A subroutine invoked from an external package via call_sv()
640 exited by calling exit.
642 =item %s() called too early to check prototype
644 (W prototype) You've called a function that has a prototype before the
645 parser saw a definition or declaration for it, and Perl could not check
646 that the call conforms to the prototype. You need to either add an
647 early prototype declaration for the subroutine in question, or move the
648 subroutine definition ahead of the call to get proper prototype
649 checking. Alternatively, if you are certain that you're calling the
650 function correctly, you may put an ampersand before the name to avoid
651 the warning. See L<perlsub>.
653 =item Calling POSIX::%s() is deprecated
655 (D deprecated) You called a function whose use is deprecated. See
656 the function's name in L<POSIX> for details.
660 (F) You passed an invalid number (like an infinity or not-a-number) to C<chr>.
662 =item Cannot compress %f in pack
664 (F) You tried compressing an infinity or not-a-number as an unsigned
665 integer with BER, which makes no sense.
667 =item Cannot compress integer in pack
669 (F) An argument to pack("w",...) was too large to compress.
670 The BER compressed integer format can only be used with positive
671 integers, and you attempted to compress a very large number (> 1e308).
672 See L<perlfunc/pack>.
674 =item Cannot compress negative numbers in pack
676 (F) An argument to pack("w",...) was negative. The BER compressed integer
677 format can only be used with positive integers. See L<perlfunc/pack>.
679 =item Cannot convert a reference to %s to typeglob
681 (F) You manipulated Perl's symbol table directly, stored a reference
682 in it, then tried to access that symbol via conventional Perl syntax.
683 The access triggers Perl to autovivify that typeglob, but it there is
684 no legal conversion from that type of reference to a typeglob.
686 =item Cannot copy to %s
688 (P) Perl detected an attempt to copy a value to an internal type that cannot
689 be directly assigned to.
691 =item Cannot find encoding "%s"
693 (S io) You tried to apply an encoding that did not exist to a filehandle,
694 either with open() or binmode().
696 =item Cannot pack %f with '%c'
698 (F) You tried converting an infinity or not-a-number to an integer,
699 which makes no sense.
701 =item Cannot printf %f with '%c'
703 (F) You tried printing an infinity or not-a-number as a character (%c),
704 which makes no sense. Maybe you meant '%s', or just stringifying it?
706 =item Cannot set tied @DB::args
708 (F) C<caller> tried to set C<@DB::args>, but found it tied. Tying C<@DB::args>
709 is not supported. (Before this error was added, it used to crash.)
711 =item Cannot tie unreifiable array
713 (P) You somehow managed to call C<tie> on an array that does not
714 keep a reference count on its arguments and cannot be made to
715 do so. Such arrays are not even supposed to be accessible to
716 Perl code, but are only used internally.
718 =item Cannot yet reorder sv_catpvfn() arguments from va_list
720 (F) Some XS code tried to use C<sv_catpvfn()> or a related function with a
721 format string that specifies explicit indexes for some of the elements, and
722 using a C-style variable-argument list (a C<va_list>). This is not currently
723 supported. XS authors wanting to do this must instead construct a C array of
724 C<SV*> scalars containing the arguments.
726 =item Can only compress unsigned integers in pack
728 (F) An argument to pack("w",...) was not an integer. The BER compressed
729 integer format can only be used with positive integers, and you attempted
730 to compress something else. See L<perlfunc/pack>.
732 =item Can't bless non-reference value
734 (F) Only hard references may be blessed. This is how Perl "enforces"
735 encapsulation of objects. See L<perlobj>.
737 =item Can't "break" in a loop topicalizer
739 (F) You called C<break>, but you're in a C<foreach> block rather than
740 a C<given> block. You probably meant to use C<next> or C<last>.
742 =item Can't "break" outside a given block
744 (F) You called C<break>, but you're not inside a C<given> block.
746 =item Can't call method "%s" on an undefined value
748 (F) You used the syntax of a method call, but the slot filled by the
749 object reference or package name contains an undefined value. Something
750 like this will reproduce the error:
753 process $BADREF 1,2,3;
754 $BADREF->process(1,2,3);
756 =item Can't call method "%s" on unblessed reference
758 (F) A method call must know in what package it's supposed to run. It
759 ordinarily finds this out from the object reference you supply, but you
760 didn't supply an object reference in this case. A reference isn't an
761 object reference until it has been blessed. See L<perlobj>.
763 =item Can't call method "%s" without a package or object reference
765 (F) You used the syntax of a method call, but the slot filled by the
766 object reference or package name contains an expression that returns a
767 defined value which is neither an object reference nor a package name.
768 Something like this will reproduce the error:
771 process $BADREF 1,2,3;
772 $BADREF->process(1,2,3);
774 =item Can't call mro_isa_changed_in() on anonymous symbol table
776 (P) Perl got confused as to whether a hash was a plain hash or a
777 symbol table hash when trying to update @ISA caches.
779 =item Can't call mro_method_changed_in() on anonymous symbol table
781 (F) An XS module tried to call C<mro_method_changed_in> on a hash that was
782 not attached to the symbol table.
784 =item Can't chdir to %s
786 (F) You called C<perl -x/foo/bar>, but F</foo/bar> is not a directory
787 that you can chdir to, possibly because it doesn't exist.
789 =item Can't check filesystem of script "%s" for nosuid
791 (P) For some reason you can't check the filesystem of the script for
794 =item Can't coerce %s to %s in %s
796 (F) Certain types of SVs, in particular real symbol table entries
797 (typeglobs), can't be forced to stop being what they are. So you can't
807 but then $foo no longer contains a glob.
809 =item Can't "continue" outside a when block
811 (F) You called C<continue>, but you're not inside a C<when>
814 =item Can't create pipe mailbox
816 (P) An error peculiar to VMS. The process is suffering from exhausted
817 quotas or other plumbing problems.
819 =item Can't declare %s in "%s"
821 (F) Only scalar, array, and hash variables may be declared as "my", "our" or
822 "state" variables. They must have ordinary identifiers as names.
824 =item Can't "default" outside a topicalizer
826 (F) You have used a C<default> block that is neither inside a
827 C<foreach> loop nor a C<given> block. (Note that this error is
828 issued on exit from the C<default> block, so you won't get the
829 error if you use an explicit C<continue>.)
831 =item Can't do inplace edit: %s is not a regular file
833 (S inplace) You tried to use the B<-i> switch on a special file, such as
834 a file in /dev, a FIFO or an uneditable directory. The file was ignored.
836 =item Can't do inplace edit on %s: %s
838 (S inplace) The creation of the new file failed for the indicated
841 =item Can't do inplace edit without backup
843 (F) You're on a system such as MS-DOS that gets confused if you try
844 reading from a deleted (but still opened) file. You have to say
845 C<-i.bak>, or some such.
847 =item Can't do inplace edit: %s would not be unique
849 (S inplace) Your filesystem does not support filenames longer than 14
850 characters and Perl was unable to create a unique filename during
851 inplace editing with the B<-i> switch. The file was ignored.
853 =item Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".
855 (W locale) You are 1) running under "C<use locale>"; 2) the current
856 locale is not a UTF-8 one; 3) you tried to do the designated case-change
857 operation on the specified Unicode character; and 4) the result of this
858 operation would mix Unicode and locale rules, which likely conflict.
859 Mixing of different rule types is forbidden, so the operation was not
860 done; instead the result is the indicated value, which is the best
861 available that uses entirely Unicode rules. That turns out to almost
862 always be the original character, unchanged.
864 It is generally a bad idea to mix non-UTF-8 locales and Unicode, and
865 this issue is one of the reasons why. This warning is raised when
866 Unicode rules would normally cause the result of this operation to
867 contain a character that is in the range specified by the locale,
868 0..255, and hence is subject to the locale's rules, not Unicode's.
870 If you are using locale purely for its characteristics related to things
871 like its numeric and time formatting (and not C<LC_CTYPE>), consider
872 using a restricted form of the locale pragma (see L<perllocale/The "use
873 locale" pragma>) like "S<C<use locale ':not_characters'>>".
875 Note that failed case-changing operations done as a result of
876 case-insensitive C</i> regular expression matching will show up in this
877 warning as having the C<fc> operation (as that is what the regular
878 expression engine calls behind the scenes.)
880 =item Can't do waitpid with flags
882 (F) This machine doesn't have either waitpid() or wait4(), so only
883 waitpid() without flags is emulated.
885 =item Can't emulate -%s on #! line
887 (F) The #! line specifies a switch that doesn't make sense at this
888 point. For example, it'd be kind of silly to put a B<-x> on the #!
891 =item Can't %s %s-endian %ss on this platform
893 (F) Your platform's byte-order is neither big-endian nor little-endian,
894 or it has a very strange pointer size. Packing and unpacking big- or
895 little-endian floating point values and pointers may not be possible.
896 See L<perlfunc/pack>.
898 =item Can't exec "%s": %s
900 (W exec) A system(), exec(), or piped open call could not execute the
901 named program for the indicated reason. Typical reasons include: the
902 permissions were wrong on the file, the file wasn't found in
903 C<$ENV{PATH}>, the executable in question was compiled for another
904 architecture, or the #! line in a script points to an interpreter that
905 can't be run for similar reasons. (Or maybe your system doesn't support
910 (F) Perl was trying to execute the indicated program for you because
911 that's what the #! line said. If that's not what you wanted, you may
912 need to mention "perl" on the #! line somewhere.
914 =item Can't execute %s
916 (F) You used the B<-S> switch, but the copies of the script to execute
917 found in the PATH did not have correct permissions.
919 =item Can't find an opnumber for "%s"
921 (F) A string of a form C<CORE::word> was given to prototype(), but there
922 is no builtin with the name C<word>.
924 =item Can't find label %s
926 (F) You said to goto a label that isn't mentioned anywhere that it's
927 possible for us to go to. See L<perlfunc/goto>.
929 =item Can't find %s on PATH
931 (F) You used the B<-S> switch, but the script to execute could not be
934 =item Can't find %s on PATH, '.' not in PATH
936 (F) You used the B<-S> switch, but the script to execute could not be
937 found in the PATH, or at least not with the correct permissions. The
938 script exists in the current directory, but PATH prohibits running it.
940 =item Can't find string terminator %s anywhere before EOF
942 (F) Perl strings can stretch over multiple lines. This message means
943 that the closing delimiter was omitted. Because bracketed quotes count
944 nesting levels, the following is missing its final parenthesis:
946 print q(The character '(' starts a side comment.);
948 If you're getting this error from a here-document, you may have
949 included unseen whitespace before or after your closing tag or there
950 may not be a linebreak after it. A good programmer's editor will have
951 a way to help you find these characters (or lack of characters). See
952 L<perlop> for the full details on here-documents.
954 =item Can't find Unicode property definition "%s"
956 =item Can't find Unicode property definition "%s" in regex; marked by <-- HERE in m/%s/
958 (F) The named property which you specified via C<\p> or C<\P> is not one
959 known to Perl. Perhaps you misspelled the name? See
960 L<perluniprops/Properties accessible through \p{} and \P{}>
961 for a complete list of available official
962 properties. If it is a
963 L<user-defined property|perlunicode/User-Defined Character Properties>
964 it must have been defined by the time the regular expression is
967 If you didn't mean to use a Unicode property, escape the C<\p>, either
968 by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, or
973 (F) A fatal error occurred while trying to fork while opening a
976 =item Can't fork, trying again in 5 seconds
978 (W pipe) A fork in a piped open failed with EAGAIN and will be retried
981 =item Can't get filespec - stale stat buffer?
983 (S) A warning peculiar to VMS. This arises because of the difference
984 between access checks under VMS and under the Unix model Perl assumes.
985 Under VMS, access checks are done by filename, rather than by bits in
986 the stat buffer, so that ACLs and other protections can be taken into
987 account. Unfortunately, Perl assumes that the stat buffer contains all
988 the necessary information, and passes it, instead of the filespec, to
989 the access-checking routine. It will try to retrieve the filespec using
990 the device name and FID present in the stat buffer, but this works only
991 if you haven't made a subsequent call to the CRTL stat() routine,
992 because the device name is overwritten with each call. If this warning
993 appears, the name lookup failed, and the access-checking routine gave up
994 and returned FALSE, just to be conservative. (Note: The access-checking
995 routine knows about the Perl C<stat> operator and file tests, so you
996 shouldn't ever see this warning in response to a Perl command; it arises
997 only if some internal code takes stat buffers lightly.)
999 =item Can't get pipe mailbox device name
1001 (P) An error peculiar to VMS. After creating a mailbox to act as a
1002 pipe, Perl can't retrieve its name for later use.
1004 =item Can't get SYSGEN parameter value for MAXBUF
1006 (P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
1007 mailbox buffers to be, and didn't get an answer.
1009 =item Can't "goto" into the middle of a foreach loop
1011 (F) A "goto" statement was executed to jump into the middle of a foreach
1012 loop. You can't get there from here. See L<perlfunc/goto>.
1014 =item Can't "goto" out of a pseudo block
1016 (F) A "goto" statement was executed to jump out of what might look like
1017 a block, except that it isn't a proper block. This usually occurs if
1018 you tried to jump out of a sort() block or subroutine, which is a no-no.
1019 See L<perlfunc/goto>.
1021 =item Can't goto subroutine from an eval-%s
1023 (F) The "goto subroutine" call can't be used to jump out of an eval
1026 =item Can't goto subroutine from a sort sub (or similar callback)
1028 (F) The "goto subroutine" call can't be used to jump out of the
1029 comparison sub for a sort(), or from a similar callback (such
1030 as the reduce() function in List::Util).
1032 =item Can't goto subroutine outside a subroutine
1034 (F) The deeply magical "goto subroutine" call can only replace one
1035 subroutine call for another. It can't manufacture one out of whole
1036 cloth. In general you should be calling it out of only an AUTOLOAD
1037 routine anyway. See L<perlfunc/goto>.
1039 =item Can't ignore signal CHLD, forcing to default
1041 (W signal) Perl has detected that it is being run with the SIGCHLD
1042 signal (sometimes known as SIGCLD) disabled. Since disabling this
1043 signal will interfere with proper determination of exit status of child
1044 processes, Perl has reset the signal to its default value. This
1045 situation typically indicates that the parent program under which Perl
1046 may be running (e.g. cron) is being very careless.
1048 =item Can't kill a non-numeric process ID
1050 (F) Process identifiers must be (signed) integers. It is a fatal error to
1051 attempt to kill() an undefined, empty-string or otherwise non-numeric
1054 =item Can't "last" outside a loop block
1056 (F) A "last" statement was executed to break out of the current block,
1057 except that there's this itty bitty problem called there isn't a current
1058 block. Note that an "if" or "else" block doesn't count as a "loopish"
1059 block, as doesn't a block given to sort(), map() or grep(). You can
1060 usually double the curlies to get the same effect though, because the
1061 inner curlies will be considered a block that loops once. See
1064 =item Can't linearize anonymous symbol table
1066 (F) Perl tried to calculate the method resolution order (MRO) of a
1067 package, but failed because the package stash has no name.
1069 =item Can't load '%s' for module %s
1071 (F) The module you tried to load failed to load a dynamic extension.
1072 This may either mean that you upgraded your version of perl to one
1073 that is incompatible with your old dynamic extensions (which is known
1074 to happen between major versions of perl), or (more likely) that your
1075 dynamic extension was built against an older version of the library
1076 that is installed on your system. You may need to rebuild your old
1079 =item Can't localize lexical variable %s
1081 (F) You used local on a variable name that was previously declared as a
1082 lexical variable using "my" or "state". This is not allowed. If you
1083 want to localize a package variable of the same name, qualify it with
1086 =item Can't localize through a reference
1088 (F) You said something like C<local $$ref>, which Perl can't currently
1089 handle, because when it goes to restore the old value of whatever $ref
1090 pointed to after the scope of the local() is finished, it can't be sure
1091 that $ref will still be a reference.
1093 =item Can't locate %s
1095 (F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be found.
1096 Perl looks for the file in all the locations mentioned in @INC, unless
1097 the file name included the full path to the file. Perhaps you need
1098 to set the PERL5LIB or PERL5OPT environment variable to say where the
1099 extra library is, or maybe the script needs to add the library name
1100 to @INC. Or maybe you just misspelled the name of the file. See
1101 L<perlfunc/require> and L<lib>.
1103 =item Can't locate auto/%s.al in @INC
1105 (F) A function (or method) was called in a package which allows
1106 autoload, but there is no function to autoload. Most probable causes
1107 are a misprint in a function/method name or a failure to C<AutoSplit>
1108 the file, say, by doing C<make install>.
1110 =item Can't locate loadable object for module %s in @INC
1112 (F) The module you loaded is trying to load an external library, like
1113 for example, F<foo.so> or F<bar.dll>, but the L<DynaLoader> module was
1114 unable to locate this library. See L<DynaLoader>.
1116 =item Can't locate object method "%s" via package "%s"
1118 (F) You called a method correctly, and it correctly indicated a package
1119 functioning as a class, but that package doesn't define that particular
1120 method, nor does any of its base classes. See L<perlobj>.
1122 =item Can't locate object method "%s" via package "%s" (perhaps you forgot
1125 (F) You called a method on a class that did not exist, and the method
1126 could not be found in UNIVERSAL. This often means that a method
1127 requires a package that has not been loaded.
1129 =item Can't locate package %s for @%s::ISA
1131 (W syntax) The @ISA array contained the name of another package that
1132 doesn't seem to exist.
1134 =item Can't locate PerlIO%s
1136 (F) You tried to use in open() a PerlIO layer that does not exist,
1137 e.g. open(FH, ">:nosuchlayer", "somefile").
1139 =item Can't make list assignment to %ENV on this system
1141 (F) List assignment to %ENV is not supported on some systems, notably
1144 =item Can't make loaded symbols global on this platform while loading %s
1146 (S) A module passed the flag 0x01 to DynaLoader::dl_load_file() to request
1147 that symbols from the stated file are made available globally within the
1148 process, but that functionality is not available on this platform. Whilst
1149 the module likely will still work, this may prevent the perl interpreter
1150 from loading other XS-based extensions which need to link directly to
1151 functions defined in the C or XS code in the stated file.
1153 =item Can't modify %s in %s
1155 (F) You aren't allowed to assign to the item indicated, or otherwise try
1156 to change it, such as with an auto-increment.
1158 =item Can't modify nonexistent substring
1160 (P) The internal routine that does assignment to a substr() was handed
1163 =item Can't modify non-lvalue subroutine call of &%s
1165 (F) Subroutines meant to be used in lvalue context should be declared as
1166 such. See L<perlsub/"Lvalue subroutines">.
1168 =item Can't modify reference to %s in %s assignment
1170 (F) Only a limited number of constructs can be used as the argument to a
1171 reference constructor on the left-hand side of an assignment, and what
1172 you used was not one of them. See L<perlref/Assigning to References>.
1174 =item Can't modify reference to localized parenthesized array in list
1177 (F) Assigning to C<\local(@array)> or C<\(local @array)> is not supported, as
1178 it is not clear exactly what it should do. If you meant to make @array
1179 refer to some other array, use C<\@array = \@other_array>. If you want to
1180 make the elements of @array aliases of the scalars referenced on the
1181 right-hand side, use C<\(@array) = @scalar_refs>.
1183 =item Can't modify reference to parenthesized hash in list assignment
1185 (F) Assigning to C<\(%hash)> is not supported. If you meant to make %hash
1186 refer to some other hash, use C<\%hash = \%other_hash>. If you want to
1187 make the elements of %hash into aliases of the scalars referenced on the
1188 right-hand side, use a hash slice: C<\@hash{@keys} = @those_scalar_refs>.
1190 =item Can't msgrcv to read-only var
1192 (F) The target of a msgrcv must be modifiable to be used as a receive
1195 =item Can't "next" outside a loop block
1197 (F) A "next" statement was executed to reiterate the current block, but
1198 there isn't a current block. Note that an "if" or "else" block doesn't
1199 count as a "loopish" block, as doesn't a block given to sort(), map() or
1200 grep(). You can usually double the curlies to get the same effect
1201 though, because the inner curlies will be considered a block that loops
1202 once. See L<perlfunc/next>.
1204 =item Can't open %s: %s
1206 (S inplace) The implicit opening of a file through use of the C<< <> >>
1207 filehandle, either implicitly under the C<-n> or C<-p> command-line
1208 switches, or explicitly, failed for the indicated reason. Usually
1209 this is because you don't have read permission for a file which
1210 you named on the command line.
1212 (F) You tried to call perl with the B<-e> switch, but F</dev/null> (or
1213 your operating system's equivalent) could not be opened.
1215 =item Can't open a reference
1217 (W io) You tried to open a scalar reference for reading or writing,
1218 using the 3-arg open() syntax:
1222 but your version of perl is compiled without perlio, and this form of
1223 open is not supported.
1225 =item Can't open bidirectional pipe
1227 (W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
1228 You can try any of several modules in the Perl library to do this, such
1229 as IPC::Open2. Alternately, direct the pipe's output to a file using
1230 ">", and then read it in under a different file handle.
1232 =item Can't open error file %s as stderr
1234 (F) An error peculiar to VMS. Perl does its own command line
1235 redirection, and couldn't open the file specified after '2>' or '2>>' on
1236 the command line for writing.
1238 =item Can't open input file %s as stdin
1240 (F) An error peculiar to VMS. Perl does its own command line
1241 redirection, and couldn't open the file specified after '<' on the
1242 command line for reading.
1244 =item Can't open output file %s as stdout
1246 (F) An error peculiar to VMS. Perl does its own command line
1247 redirection, and couldn't open the file specified after '>' or '>>' on
1248 the command line for writing.
1250 =item Can't open output pipe (name: %s)
1252 (P) An error peculiar to VMS. Perl does its own command line
1253 redirection, and couldn't open the pipe into which to send data destined
1256 =item Can't open perl script "%s": %s
1258 (F) The script you specified can't be opened for the indicated reason.
1260 If you're debugging a script that uses #!, and normally relies on the
1261 shell's $PATH search, the -S option causes perl to do that search, so
1262 you don't have to type the path or C<`which $scriptname`>.
1264 =item Can't read CRTL environ
1266 (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
1267 from the CRTL's internal environment array and discovered the array was
1268 missing. You need to figure out where your CRTL misplaced its environ
1269 or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
1272 =item Can't redeclare "%s" in "%s"
1274 (F) A "my", "our" or "state" declaration was found within another declaration,
1275 such as C<my ($x, my($y), $z)> or C<our (my $x)>.
1277 =item Can't "redo" outside a loop block
1279 (F) A "redo" statement was executed to restart the current block, but
1280 there isn't a current block. Note that an "if" or "else" block doesn't
1281 count as a "loopish" block, as doesn't a block given to sort(), map()
1282 or grep(). You can usually double the curlies to get the same effect
1283 though, because the inner curlies will be considered a block that
1284 loops once. See L<perlfunc/redo>.
1286 =item Can't remove %s: %s, skipping file
1288 (S inplace) You requested an inplace edit without creating a backup
1289 file. Perl was unable to remove the original file to replace it with
1290 the modified file. The file was left unmodified.
1292 =item Can't rename %s to %s: %s, skipping file
1294 (S inplace) The rename done by the B<-i> switch failed for some reason,
1295 probably because you don't have write permission to the directory.
1297 =item Can't reopen input pipe (name: %s) in binary mode
1299 (P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
1300 to reopen it to accept binary data. Alas, it failed.
1302 =item Can't represent character for Ox%X on this platform
1304 (F) There is a hard limit to how big a character code point can be due
1305 to the fundamental properties of UTF-8, especially on EBCDIC
1306 platforms. The given code point exceeds that. The only work-around is
1307 to not use such a large code point.
1309 =item Can't reset %ENV on this system
1311 (F) You called C<reset('E')> or similar, which tried to reset
1312 all variables in the current package beginning with "E". In
1313 the main package, that includes %ENV. Resetting %ENV is not
1314 supported on some systems, notably VMS.
1316 =item Can't resolve method "%s" overloading "%s" in package "%s"
1318 (F)(P) Error resolving overloading specified by a method name (as
1319 opposed to a subroutine reference): no such method callable via the
1320 package. If the method name is C<???>, this is an internal error.
1322 =item Can't return %s from lvalue subroutine
1324 (F) Perl detected an attempt to return illegal lvalues (such as
1325 temporary or readonly values) from a subroutine used as an lvalue. This
1328 =item Can't return outside a subroutine
1330 (F) The return statement was executed in mainline code, that is, where
1331 there was no subroutine call to return out of. See L<perlsub>.
1333 =item Can't return %s to lvalue scalar context
1335 (F) You tried to return a complete array or hash from an lvalue
1336 subroutine, but you called the subroutine in a way that made Perl
1337 think you meant to return only one value. You probably meant to
1338 write parentheses around the call to the subroutine, which tell
1339 Perl that the call should be in list context.
1341 =item Can't stat script "%s"
1343 (P) For some reason you can't fstat() the script even though you have it
1344 open already. Bizarre.
1346 =item Can't take log of %g
1348 (F) For ordinary real numbers, you can't take the logarithm of a
1349 negative number or zero. There's a Math::Complex package that comes
1350 standard with Perl, though, if you really want to do that for the
1353 =item Can't take sqrt of %g
1355 (F) For ordinary real numbers, you can't take the square root of a
1356 negative number. There's a Math::Complex package that comes standard
1357 with Perl, though, if you really want to do that.
1359 =item Can't undef active subroutine
1361 (F) You can't undefine a routine that's currently running. You can,
1362 however, redefine it while it's running, and you can even undef the
1363 redefined subroutine while the old routine is running. Go figure.
1365 =item Can't upgrade %s (%d) to %d
1367 (P) The internal sv_upgrade routine adds "members" to an SV, making it
1368 into a more specialized kind of SV. The top several SV types are so
1369 specialized, however, that they cannot be interconverted. This message
1370 indicates that such a conversion was attempted.
1372 =item Can't use '%c' after -mname
1374 (F) You tried to call perl with the B<-m> switch, but you put something
1375 other than "=" after the module name.
1377 =item Can't use a hash as a reference
1379 (F) You tried to use a hash as a reference, as in
1380 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl
1381 <= 5.22.0 used to allow this syntax, but shouldn't
1382 have. This was deprecated in perl 5.6.1.
1384 =item Can't use an array as a reference
1386 (F) You tried to use an array as a reference, as in
1387 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.22.0
1388 used to allow this syntax, but shouldn't have. This
1389 was deprecated in perl 5.6.1.
1391 =item Can't use anonymous symbol table for method lookup
1393 (F) The internal routine that does method lookup was handed a symbol
1394 table that doesn't have a name. Symbol tables can become anonymous
1395 for example by undefining stashes: C<undef %Some::Package::>.
1397 =item Can't use an undefined value as %s reference
1399 (F) A value used as either a hard reference or a symbolic reference must
1400 be a defined value. This helps to delurk some insidious errors.
1402 =item Can't use bareword ("%s") as %s ref while "strict refs" in use
1404 (F) Only hard references are allowed by "strict refs". Symbolic
1405 references are disallowed. See L<perlref>.
1407 =item Can't use %! because Errno.pm is not available
1409 (F) The first time the C<%!> hash is used, perl automatically loads the
1410 Errno.pm module. The Errno module is expected to tie the %! hash to
1411 provide symbolic names for C<$!> errno values.
1413 =item Can't use both '<' and '>' after type '%c' in %s
1415 (F) A type cannot be forced to have both big-endian and little-endian
1416 byte-order at the same time, so this combination of modifiers is not
1417 allowed. See L<perlfunc/pack>.
1419 =item Can't use 'defined(@array)' (Maybe you should just omit the defined()?)
1421 (F) defined() is not useful on arrays because it
1422 checks for an undefined I<scalar> value. If you want to see if the
1423 array is empty, just use C<if (@array) { # not empty }> for example.
1425 =item Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)
1427 (F) C<defined()> is not usually right on hashes.
1429 Although C<defined %hash> is false on a plain not-yet-used hash, it
1430 becomes true in several non-obvious circumstances, including iterators,
1431 weak references, stash names, even remaining true after C<undef %hash>.
1432 These things make C<defined %hash> fairly useless in practice, so it now
1433 generates a fatal error.
1435 If a check for non-empty is what you wanted then just put it in boolean
1436 context (see L<perldata/Scalar values>):
1442 If you had C<defined %Foo::Bar::QUUX> to check whether such a package
1443 variable exists then that's never really been reliable, and isn't
1444 a good way to enquire about the features of a package, or whether
1447 =item Can't use %s for loop variable
1449 (P) The parser got confused when trying to parse a C<foreach> loop.
1451 =item Can't use global %s in "%s"
1453 (F) You tried to declare a magical variable as a lexical variable. This
1454 is not allowed, because the magic can be tied to only one location
1455 (namely the global variable) and it would be incredibly confusing to
1456 have variables in your program that looked like magical variables but
1459 =item Can't use '%c' in a group with different byte-order in %s
1461 (F) You attempted to force a different byte-order on a type
1462 that is already inside a group with a byte-order modifier.
1463 For example you cannot force little-endianness on a type that
1464 is inside a big-endian group.
1466 =item Can't use "my %s" in sort comparison
1468 (F) The global variables $a and $b are reserved for sort comparisons.
1469 You mentioned $a or $b in the same line as the <=> or cmp operator,
1470 and the variable had earlier been declared as a lexical variable.
1471 Either qualify the sort variable with the package name, or rename the
1474 =item Can't use %s ref as %s ref
1476 (F) You've mixed up your reference types. You have to dereference a
1477 reference of the type needed. You can use the ref() function to
1478 test the type of the reference, if need be.
1480 =item Can't use string ("%s") as %s ref while "strict refs" in use
1482 =item Can't use string ("%s"...) as %s ref while "strict refs" in use
1484 (F) You've told Perl to dereference a string, something which
1485 C<use strict> blocks to prevent it happening accidentally. See
1486 L<perlref/"Symbolic references">. This can be triggered by an C<@> or C<$>
1487 in a double-quoted string immediately before interpolating a variable,
1488 for example in C<"user @$twitter_id">, which says to treat the contents
1489 of C<$twitter_id> as an array reference; use a C<\> to have a literal C<@>
1490 symbol followed by the contents of C<$twitter_id>: C<"user \@$twitter_id">.
1492 =item Can't use subscript on %s
1494 (F) The compiler tried to interpret a bracketed expression as a
1495 subscript. But to the left of the brackets was an expression that
1496 didn't look like a hash or array reference, or anything else subscriptable.
1498 =item Can't use \%c to mean $%c in expression
1500 (W syntax) In an ordinary expression, backslash is a unary operator that
1501 creates a reference to its argument. The use of backslash to indicate a
1502 backreference to a matched substring is valid only as part of a regular
1503 expression pattern. Trying to do this in ordinary Perl code produces a
1504 value that prints out looking like SCALAR(0xdecaf). Use the $1 form
1507 =item Can't weaken a nonreference
1509 (F) You attempted to weaken something that was not a reference. Only
1510 references can be weakened.
1512 =item Can't "when" outside a topicalizer
1514 (F) You have used a when() block that is neither inside a C<foreach>
1515 loop nor a C<given> block. (Note that this error is issued on exit
1516 from the C<when> block, so you won't get the error if the match fails,
1517 or if you use an explicit C<continue>.)
1519 =item Can't x= to read-only value
1521 (F) You tried to repeat a constant value (often the undefined value)
1522 with an assignment operator, which implies modifying the value itself.
1523 Perhaps you need to copy the value to a temporary, and repeat that.
1525 =item Character following "\c" must be printable ASCII
1527 (F) In C<\cI<X>>, I<X> must be a printable (non-control) ASCII character.
1529 Note that ASCII characters that don't map to control characters are
1530 discouraged, and will generate the warning (when enabled)
1531 L</""\c%c" is more clearly written simply as "%s"">.
1533 =item Character following \%c must be '{' or a single-character Unicode property name in regex; marked by <-- HERE in m/%s/
1535 (F) (In the above the C<%c> is replaced by either C<p> or C<P>.) You
1536 specified something that isn't a legal Unicode property name. Most
1537 Unicode properties are specified by C<\p{...}>. But if the name is a
1538 single character one, the braces may be omitted.
1540 =item Character in 'C' format wrapped in pack
1546 where $x is either less than 0 or more than 255; the C<"C"> format is
1547 only for encoding native operating system characters (ASCII, EBCDIC,
1548 and so on) and not for Unicode characters, so Perl behaved as if you meant
1552 If you actually want to pack Unicode codepoints, use the C<"U"> format
1555 =item Character in 'c' format wrapped in pack
1561 where $x is either less than -128 or more than 127; the C<"c"> format
1562 is only for encoding native operating system characters (ASCII, EBCDIC,
1563 and so on) and not for Unicode characters, so Perl behaved as if you meant
1565 pack("c", $x & 255);
1567 If you actually want to pack Unicode codepoints, use the C<"U"> format
1570 =item Character in '%c' format wrapped in unpack
1572 (W unpack) You tried something like
1574 unpack("H", "\x{2a1}")
1576 where the format expects to process a byte (a character with a value
1577 below 256), but a higher value was provided instead. Perl uses the
1578 value modulus 256 instead, as if you had provided:
1580 unpack("H", "\x{a1}")
1582 =item Character in 'W' format wrapped in pack
1588 where $x is either less than 0 or more than 255. However, C<U0>-mode
1589 expects all values to fall in the interval [0, 255], so Perl behaved
1592 pack("U0W", $x & 255)
1594 =item Character(s) in '%c' format wrapped in pack
1596 (W pack) You tried something like
1598 pack("u", "\x{1f3}b")
1600 where the format expects to process a sequence of bytes (character with a
1601 value below 256), but some of the characters had a higher value. Perl
1602 uses the character values modulus 256 instead, as if you had provided:
1604 pack("u", "\x{f3}b")
1606 =item Character(s) in '%c' format wrapped in unpack
1608 (W unpack) You tried something like
1610 unpack("s", "\x{1f3}b")
1612 where the format expects to process a sequence of bytes (character with a
1613 value below 256), but some of the characters had a higher value. Perl
1614 uses the character values modulus 256 instead, as if you had provided:
1616 unpack("s", "\x{f3}b")
1618 =item charnames alias definitions may not contain a sequence of multiple spaces
1620 (F) You defined a character name which had multiple space characters
1621 in a row. Change them to single spaces. Usually these names are
1622 defined in the C<:alias> import argument to C<use charnames>, but they
1623 could be defined by a translator installed into C<$^H{charnames}>. See
1624 L<charnames/CUSTOM ALIASES>.
1626 =item charnames alias definitions may not contain trailing white-space
1628 (F) You defined a character name which ended in a space
1629 character. Remove the trailing space(s). Usually these names are
1630 defined in the C<:alias> import argument to C<use charnames>, but they
1631 could be defined by a translator installed into C<$^H{charnames}>.
1632 See L<charnames/CUSTOM ALIASES>.
1634 =item chdir() on unopened filehandle %s
1636 (W unopened) You tried chdir() on a filehandle that was never opened.
1638 =item "\c%c" is more clearly written simply as "%s"
1640 (W syntax) The C<\cI<X>> construct is intended to be a way to specify
1641 non-printable characters. You used it for a printable one, which
1642 is better written as simply itself, perhaps preceded by a backslash
1643 for non-word characters. Doing it the way you did is not portable
1644 between ASCII and EBCDIC platforms.
1646 =item Cloning substitution context is unimplemented
1648 (F) Creating a new thread inside the C<s///> operator is not supported.
1650 =item closedir() attempted on invalid dirhandle %s
1652 (W io) The dirhandle you tried to close is either closed or not really
1653 a dirhandle. Check your control flow.
1655 =item close() on unopened filehandle %s
1657 (W unopened) You tried to close a filehandle that was never opened.
1659 =item Closure prototype called
1661 (F) If a closure has attributes, the subroutine passed to an attribute
1662 handler is the prototype that is cloned when a new closure is created.
1663 This subroutine cannot be called.
1665 =item \C no longer supported in regex; marked by S<<-- HERE> in m/%s/
1667 (F) The \C character class used to allow a match of single byte
1668 within a multi-byte utf-8 character, but was removed in v5.24 as
1669 it broke encapsulation and its implementation was extremely buggy.
1670 If you really need to process the individual bytes, you probably
1671 want to convert your string to one where each underlying byte is
1672 stored as a character, with utf8::encode().
1674 =item Code missing after '/'
1676 (F) You had a (sub-)template that ends with a '/'. There must be
1677 another template code following the slash. See L<perlfunc/pack>.
1679 =item Code point 0x%X is not Unicode, and not portable
1681 (S non_unicode) You had a code point that has never been in any
1682 standard, so it is likely that languages other than Perl will NOT
1683 understand it. At one time, it was legal in some standards to have code
1684 points up to 0x7FFF_FFFF, but not higher, and this code point is higher.
1686 Acceptance of these code points is a Perl extension, and you should
1687 expect that nothing other than Perl can handle them; Perl itself on
1688 EBCDIC platforms before v5.24 does not handle them.
1690 Code points above 0xFFFF_FFFF require larger than a 32 bit word.
1692 Perl also makes no guarantees that the representation of these code
1693 points won't change at some point in the future, say when machines
1694 become available that have larger than a 64-bit word. At that time,
1695 files written by an older Perl would require conversion before being
1696 readable by a newer Perl.
1698 =item Code point 0x%X is not Unicode, may not be portable
1700 (S non_unicode) You had a code point above the Unicode maximum
1703 Perl allows strings to contain a superset of Unicode code points, but
1704 these may not be accepted by other languages/systems. Further, even if
1705 these languages/systems accept these large code points, they may have
1706 chosen a different representation for them than the UTF-8-like one that
1707 Perl has, which would mean files are not exchangeable between them and
1710 On EBCDIC platforms, code points above 0x3FFF_FFFF have a different
1711 representation in Perl v5.24 than before, so any file containing these
1712 that was written before that version will require conversion before
1713 being readable by a later Perl.
1715 =item %s: Command not found
1717 (A) You've accidentally run your script through B<csh> or another shell
1718 instead of Perl. Check the #! line, or manually feed your script into
1719 Perl yourself. The #! line at the top of your file could look like
1723 =item %s: command not found
1725 (A) You've accidentally run your script through B<bash> or another shell
1726 instead of Perl. Check the #! line, or manually feed your script into
1727 Perl yourself. The #! line at the top of your file could look like
1731 =item %s: command not found: %s
1733 (A) You've accidentally run your script through B<zsh> or another shell
1734 instead of Perl. Check the #! line, or manually feed your script into
1735 Perl yourself. The #! line at the top of your file could look like
1739 =item Compilation failed in require
1741 (F) Perl could not compile a file specified in a C<require> statement.
1742 Perl uses this generic message when none of the errors that it
1743 encountered were severe enough to halt compilation immediately.
1745 =item Complex regular subexpression recursion limit (%d) exceeded
1747 (W regexp) The regular expression engine uses recursion in complex
1748 situations where back-tracking is required. Recursion depth is limited
1749 to 32766, or perhaps less in architectures where the stack cannot grow
1750 arbitrarily. ("Simple" and "medium" situations are handled without
1751 recursion and are not subject to a limit.) Try shortening the string
1752 under examination; looping in Perl code (e.g. with C<while>) rather than
1753 in the regular expression engine; or rewriting the regular expression so
1754 that it is simpler or backtracks less. (See L<perlfaq2> for information
1755 on I<Mastering Regular Expressions>.)
1757 =item connect() on closed socket %s
1759 (W closed) You tried to do a connect on a closed socket. Did you forget
1760 to check the return value of your socket() call? See
1761 L<perlfunc/connect>.
1763 =item Constant(%s): Call to &{$^H{%s}} did not return a defined value
1765 (F) The subroutine registered to handle constant overloading
1766 (see L<overload>) or a custom charnames handler (see
1767 L<charnames/CUSTOM TRANSLATORS>) returned an undefined value.
1769 =item Constant(%s): $^H{%s} is not defined
1771 (F) The parser found inconsistencies while attempting to define an
1772 overloaded constant. Perhaps you forgot to load the corresponding
1775 =item Constant is not %s reference
1777 (F) A constant value (perhaps declared using the C<use constant> pragma)
1778 is being dereferenced, but it amounts to the wrong type of reference.
1779 The message indicates the type of reference that was expected. This
1780 usually indicates a syntax error in dereferencing the constant value.
1781 See L<perlsub/"Constant Functions"> and L<constant>.
1783 =item Constants from lexical variables potentially modified elsewhere are
1786 (D deprecated) You wrote something like
1789 $sub = sub () { $var };
1791 but $var is referenced elsewhere and could be modified after the C<sub>
1792 expression is evaluated. Either it is explicitly modified elsewhere
1793 (C<$var = 3>) or it is passed to a subroutine or to an operator like
1794 C<printf> or C<map>, which may or may not modify the variable.
1796 Traditionally, Perl has captured the value of the variable at that
1797 point and turned the subroutine into a constant eligible for inlining.
1798 In those cases where the variable can be modified elsewhere, this
1799 breaks the behavior of closures, in which the subroutine captures
1800 the variable itself, rather than its value, so future changes to the
1801 variable are reflected in the subroutine's return value.
1803 This usage is deprecated, because the behavior is likely to change
1804 in a future version of Perl.
1806 If you intended for the subroutine to be eligible for inlining, then
1807 make sure the variable is not referenced elsewhere, possibly by
1811 $sub = sub () { $var2 };
1813 If you do want this subroutine to be a closure that reflects future
1814 changes to the variable that it closes over, add an explicit C<return>:
1817 $sub = sub () { return $var };
1819 =item Constant subroutine %s redefined
1821 (W redefine)(S) You redefined a subroutine which had previously
1822 been eligible for inlining. See L<perlsub/"Constant Functions">
1823 for commentary and workarounds.
1825 =item Constant subroutine %s undefined
1827 (W misc) You undefined a subroutine which had previously been eligible
1828 for inlining. See L<perlsub/"Constant Functions"> for commentary and
1831 =item Constant(%s) unknown
1833 (F) The parser found inconsistencies either while attempting
1834 to define an overloaded constant, or when trying to find the
1835 character name specified in the C<\N{...}> escape. Perhaps you
1836 forgot to load the corresponding L<overload> pragma?
1838 =item :const is experimental
1840 (S experimental::const_attr) The "const" attribute is experimental.
1841 If you want to use the feature, disable the warning with C<no warnings
1842 'experimental::const_attr'>, but know that in doing so you are taking
1843 the risk that your code may break in a future Perl version.
1845 =item :const is not permitted on named subroutines
1847 (F) The "const" attribute causes an anonymous subroutine to be run and
1848 its value captured at the time that it is cloned. Named subroutines are
1849 not cloned like this, so the attribute does not make sense on them.
1851 =item Copy method did not return a reference
1853 (F) The method which overloads "=" is buggy. See
1854 L<overload/Copy Constructor>.
1856 =item &CORE::%s cannot be called directly
1858 (F) You tried to call a subroutine in the C<CORE::> namespace
1859 with C<&foo> syntax or through a reference. Some subroutines
1860 in this package cannot yet be called that way, but must be
1861 called as barewords. Something like this will work:
1863 BEGIN { *shove = \&CORE::push; }
1864 shove @array, 1,2,3; # pushes on to @array
1866 =item CORE::%s is not a keyword
1868 (F) The CORE:: namespace is reserved for Perl keywords.
1870 =item Corrupted regexp opcode %d > %d
1872 (P) This is either an error in Perl, or, if you're using
1873 one, your L<custom regular expression engine|perlreapi>. If not the
1874 latter, report the problem through the L<perlbug> utility.
1876 =item corrupted regexp pointers
1878 (P) The regular expression engine got confused by what the regular
1879 expression compiler gave it.
1881 =item corrupted regexp program
1883 (P) The regular expression engine got passed a regexp program without a
1886 =item Corrupt malloc ptr 0x%x at 0x%x
1888 (P) The malloc package that comes with Perl had an internal failure.
1890 =item Count after length/code in unpack
1892 (F) You had an unpack template indicating a counted-length string, but
1893 you have also specified an explicit size for the string. See
1897 The following are used in lib/diagnostics.t for testing two =items that
1898 share the same description. Changes here need to be propagated to there
1900 =item Deep recursion on anonymous subroutine
1902 =item Deep recursion on subroutine "%s"
1904 (W recursion) This subroutine has called itself (directly or indirectly)
1905 100 times more than it has returned. This probably indicates an
1906 infinite recursion, unless you're writing strange benchmark programs, in
1907 which case it indicates something else.
1909 This threshold can be changed from 100, by recompiling the F<perl> binary,
1910 setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1912 =item (?(DEFINE)....) does not allow branches in regex; marked by
1913 S<<-- HERE> in m/%s/
1915 (F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
1916 most likely cause of this error is that you left out a parenthesis inside
1917 of the C<....> part.
1919 The S<<-- HERE> shows whereabouts in the regular expression the problem was
1922 =item %s defines neither package nor VERSION--version check failed
1924 (F) You said something like "use Module 42" but in the Module file
1925 there are neither package declarations nor a C<$VERSION>.
1927 =item delete argument is index/value array slice, use array slice
1929 (F) You used index/value array slice syntax (C<%array[...]>) as
1930 the argument to C<delete>. You probably meant C<@array[...]> with
1931 an @ symbol instead.
1933 =item delete argument is key/value hash slice, use hash slice
1935 (F) You used key/value hash slice syntax (C<%hash{...}>) as the argument to
1936 C<delete>. You probably meant C<@hash{...}> with an @ symbol instead.
1938 =item delete argument is not a HASH or ARRAY element or slice
1940 (F) The argument to C<delete> must be either a hash or array element,
1946 or a hash or array slice, such as:
1948 @foo[$bar, $baz, $xyzzy]
1949 @{$ref->[12]}{"susie", "queue"}
1951 =item Delimiter for here document is too long
1953 (F) In a here document construct like C<<<FOO>, the label C<FOO> is too
1954 long for Perl to handle. You have to be seriously twisted to write code
1955 that triggers this error.
1957 =item Deprecated use of my() in false conditional
1959 (D deprecated) You used a declaration similar to C<my $x if 0>. There
1960 has been a long-standing bug in Perl that causes a lexical variable
1961 not to be cleared at scope exit when its declaration includes a false
1962 conditional. Some people have exploited this bug to achieve a kind of
1963 static variable. Since we intend to fix this bug, we don't want people
1964 relying on this behavior. You can achieve a similar static effect by
1965 declaring the variable in a separate block outside the function, eg
1967 sub f { my $x if 0; return $x++ }
1971 { my $x; sub f { return $x++ } }
1973 Beginning with perl 5.10.0, you can also use C<state> variables to have
1974 lexicals that are initialized only once (see L<feature>):
1976 sub f { state $x; return $x++ }
1978 =item DESTROY created new reference to dead object '%s'
1980 (F) A DESTROY() method created a new reference to the object which is
1981 just being DESTROYed. Perl is confused, and prefers to abort rather
1982 than to create a dangling reference.
1984 =item Did not produce a valid header
1988 =item %s did not return a true value
1990 (F) A required (or used) file must return a true value to indicate that
1991 it compiled correctly and ran its initialization code correctly. It's
1992 traditional to end such a file with a "1;", though any true value would
1993 do. See L<perlfunc/require>.
1995 =item (Did you mean &%s instead?)
1997 (W misc) You probably referred to an imported subroutine &FOO as $FOO or
2000 =item (Did you mean "local" instead of "our"?)
2002 (W misc) Remember that "our" does not localize the declared global
2003 variable. You have declared it again in the same lexical scope, which
2006 =item (Did you mean $ or @ instead of %?)
2008 (W) You probably said %hash{$key} when you meant $hash{$key} or
2009 @hash{@keys}. On the other hand, maybe you just meant %hash and got
2014 (F) You passed die() an empty string (the equivalent of C<die "">) or
2015 you called it with no args and C<$@> was empty.
2017 =item Document contains no data
2021 =item %s does not define %s::VERSION--version check failed
2023 (F) You said something like "use Module 42" but the Module did not
2024 define a C<$VERSION>.
2026 =item '/' does not take a repeat count
2028 (F) You cannot put a repeat count of any kind right after the '/' code.
2029 See L<perlfunc/pack>.
2031 =item Don't know how to get file name
2033 (P) C<PerlIO_getname>, a perl internal I/O function specific to VMS, was
2034 somehow called on another platform. This should not happen.
2036 =item Don't know how to handle magic of type \%o
2038 (P) The internal handling of magical variables has been cursed.
2040 =item do_study: out of memory
2042 (P) This should have been caught by safemalloc() instead.
2044 =item (Do you need to predeclare %s?)
2046 (S syntax) This is an educated guess made in conjunction with the message
2047 "%s found where operator expected". It often means a subroutine or module
2048 name is being referenced that hasn't been declared yet. This may be
2049 because of ordering problems in your file, or because of a missing
2050 "sub", "package", "require", or "use" statement. If you're referencing
2051 something that isn't defined yet, you don't actually have to define the
2052 subroutine or package before the current location. You can use an empty
2053 "sub foo;" or "package FOO;" to enter a "forward" declaration.
2055 =item dump() better written as CORE::dump()
2057 (W misc) You used the obsolescent C<dump()> built-in function, without fully
2058 qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
2060 =item dump is not supported
2062 (F) Your machine doesn't support dump/undump.
2064 =item Duplicate free() ignored
2066 (S malloc) An internal routine called free() on something that had
2069 =item Duplicate modifier '%c' after '%c' in %s
2071 (W unpack) You have applied the same modifier more than once after a
2072 type in a pack template. See L<perlfunc/pack>.
2074 =item elseif should be elsif
2076 (S syntax) There is no keyword "elseif" in Perl because Larry thinks
2077 it's ugly. Your code will be interpreted as an attempt to call a method
2078 named "elseif" for the class returned by the following block. This is
2079 unlikely to be what you want.
2081 =item Empty \%c in regex; marked by S<<-- HERE> in m/%s/
2083 =item Empty \%c{} in regex; marked by S<<-- HERE> in m/%s/
2085 (F) C<\p> and C<\P> are used to introduce a named Unicode property, as
2086 described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
2087 a regular expression without specifying the property name.
2089 =item entering effective %s failed
2091 (F) While under the C<use filetest> pragma, switching the real and
2092 effective uids or gids failed.
2094 =item %ENV is aliased to %s
2096 (F) You're running under taint mode, and the C<%ENV> variable has been
2097 aliased to another hash, so it doesn't reflect anymore the state of the
2098 program's environment. This is potentially insecure.
2100 =item Error converting file specification %s
2102 (F) An error peculiar to VMS. Because Perl may have to deal with file
2103 specifications in either VMS or Unix syntax, it converts them to a
2104 single form when it must operate on them directly. Either you've passed
2105 an invalid file specification to Perl, or you've found a case the
2106 conversion routines don't handle. Drat.
2108 =item Eval-group in insecure regular expression
2110 (F) Perl detected tainted data when trying to compile a regular
2111 expression that contains the C<(?{ ... })> zero-width assertion, which
2112 is unsafe. See L<perlre/(?{ code })>, and L<perlsec>.
2114 =item Eval-group not allowed at runtime, use re 'eval' in regex m/%s/
2116 (F) Perl tried to compile a regular expression containing the
2117 C<(?{ ... })> zero-width assertion at run time, as it would when the
2118 pattern contains interpolated values. Since that is a security risk,
2119 it is not allowed. If you insist, you may still do this by using the
2120 C<re 'eval'> pragma or by explicitly building the pattern from an
2121 interpolated string at run time and using that in an eval(). See
2122 L<perlre/(?{ code })>.
2124 =item Eval-group not allowed, use re 'eval' in regex m/%s/
2126 (F) A regular expression contained the C<(?{ ... })> zero-width
2127 assertion, but that construct is only allowed when the C<use re 'eval'>
2128 pragma is in effect. See L<perlre/(?{ code })>.
2130 =item EVAL without pos change exceeded limit in regex; marked by
2131 S<<-- HERE> in m/%s/
2133 (F) You used a pattern that nested too many EVAL calls without consuming
2134 any text. Restructure the pattern so that text is consumed.
2136 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2139 =item Excessively long <> operator
2141 (F) The contents of a <> operator may not exceed the maximum size of a
2142 Perl identifier. If you're just trying to glob a long list of
2143 filenames, try using the glob() operator, or put the filenames into a
2144 variable and glob that.
2146 =item exec? I'm not *that* kind of operating system
2148 (F) The C<exec> function is not implemented on some systems, e.g., Symbian
2149 OS. See L<perlport>.
2151 =item Execution of %s aborted due to compilation errors.
2153 (F) The final summary message when a Perl compilation fails.
2155 =item exists argument is not a HASH or ARRAY element or a subroutine
2157 (F) The argument to C<exists> must be a hash or array element or a
2158 subroutine with an ampersand, such as:
2164 =item exists argument is not a subroutine name
2166 (F) The argument to C<exists> for C<exists &sub> must be a subroutine name,
2167 and not a subroutine call. C<exists &sub()> will generate this error.
2169 =item Exiting eval via %s
2171 (W exiting) You are exiting an eval by unconventional means, such as a
2172 goto, or a loop control statement.
2174 =item Exiting format via %s
2176 (W exiting) You are exiting a format by unconventional means, such as a
2177 goto, or a loop control statement.
2179 =item Exiting pseudo-block via %s
2181 (W exiting) You are exiting a rather special block construct (like a
2182 sort block or subroutine) by unconventional means, such as a goto, or a
2183 loop control statement. See L<perlfunc/sort>.
2185 =item Exiting subroutine via %s
2187 (W exiting) You are exiting a subroutine by unconventional means, such
2188 as a goto, or a loop control statement.
2190 =item Exiting substitution via %s
2192 (W exiting) You are exiting a substitution by unconventional means, such
2193 as a return, a goto, or a loop control statement.
2195 =item Expecting close bracket in regex; marked by S<<-- HERE> in m/%s/
2197 (F) You wrote something like
2201 to denote a capturing group of the form
2202 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>,
2203 but omitted the C<")">.
2205 =item Expecting '(?flags:(?[...' in regex; marked by S<<-- HERE> in m/%s/
2207 (F) The C<(?[...])> extended character class regular expression construct
2208 only allows character classes (including character class escapes like
2209 C<\d>), operators, and parentheses. The one exception is C<(?flags:...)>
2210 containing at least one flag and exactly one C<(?[...])> construct.
2211 This allows a regular expression containing just C<(?[...])> to be
2212 interpolated. If you see this error message, then you probably
2213 have some other C<(?...)> construct inside your character class. See
2214 L<perlrecharclass/Extended Bracketed Character Classes>.
2216 =item Experimental aliasing via reference not enabled
2218 (F) To do aliasing via references, you must first enable the feature:
2220 no warnings "experimental::refaliasing";
2221 use feature "refaliasing";
2224 =item Experimental %s on scalar is now forbidden
2226 (F) An experimental feature added in Perl 5.14 allowed C<each>, C<keys>,
2227 C<push>, C<pop>, C<shift>, C<splice>, C<unshift>, and C<values> to be called with a
2228 scalar argument. This experiment is considered unsuccessful, and
2229 has been removed. The C<postderef> feature may meet your needs better.
2231 =item Experimental subroutine signatures not enabled
2233 (F) To use subroutine signatures, you must first enable them:
2235 no warnings "experimental::signatures";
2236 use feature "signatures";
2237 sub foo ($left, $right) { ... }
2239 =item Explicit blessing to '' (assuming package main)
2241 (W misc) You are blessing a reference to a zero length string. This has
2242 the effect of blessing the reference into the package main. This is
2243 usually not what you want. Consider providing a default target package,
2244 e.g. bless($ref, $p || 'MyPackage');
2246 =item %s: Expression syntax
2248 (A) You've accidentally run your script through B<csh> instead of Perl.
2249 Check the #! line, or manually feed your script into Perl yourself.
2251 =item %s failed--call queue aborted
2253 (F) An untrapped exception was raised while executing a UNITCHECK,
2254 CHECK, INIT, or END subroutine. Processing of the remainder of the
2255 queue of such routines has been prematurely ended.
2257 =item Failed to close in-place edit file %s: %s
2259 (F) Closing an output file from in-place editing, as with the C<-i>
2260 command-line switch, failed.
2262 =item False [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2264 (W regexp)(F) A character class range must start and end at a literal
2265 character, not another character class like C<\d> or C<[:alpha:]>. The "-"
2266 in your false range is interpreted as a literal "-". In a C<(?[...])>
2267 construct, this is an error, rather than a warning. Consider quoting
2268 the "-", "\-". The S<<-- HERE> shows whereabouts in the regular expression
2269 the problem was discovered. See L<perlre>.
2271 =item Fatal VMS error (status=%d) at %s, line %d
2273 (P) An error peculiar to VMS. Something untoward happened in a VMS
2274 system service or RTL routine; Perl's exit status should provide more
2275 details. The filename in "at %s" and the line number in "line %d" tell
2276 you which section of the Perl source code is distressed.
2278 =item fcntl is not implemented
2280 (F) Your machine apparently doesn't implement fcntl(). What is this, a
2281 PDP-11 or something?
2283 =item FETCHSIZE returned a negative value
2285 (F) A tied array claimed to have a negative number of elements, which
2288 =item Field too wide in 'u' format in pack
2290 (W pack) Each line in an uuencoded string starts with a length indicator
2291 which can't encode values above 63. So there is no point in asking for
2292 a line length bigger than that. Perl will behave as if you specified
2293 C<u63> as the format.
2295 =item Filehandle %s opened only for input
2297 (W io) You tried to write on a read-only filehandle. If you intended
2298 it to be a read-write filehandle, you needed to open it with "+<" or
2299 "+>" or "+>>" instead of with "<" or nothing. If you intended only to
2300 write the file, use ">" or ">>". See L<perlfunc/open>.
2302 =item Filehandle %s opened only for output
2304 (W io) You tried to read from a filehandle opened only for writing, If
2305 you intended it to be a read/write filehandle, you needed to open it
2306 with "+<" or "+>" or "+>>" instead of with ">". If you intended only to
2307 read from the file, use "<". See L<perlfunc/open>. Another possibility
2308 is that you attempted to open filedescriptor 0 (also known as STDIN) for
2309 output (maybe you closed STDIN earlier?).
2311 =item Filehandle %s reopened as %s only for input
2313 (W io) You opened for reading a filehandle that got the same filehandle id
2314 as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR
2317 =item Filehandle STDIN reopened as %s only for output
2319 (W io) You opened for writing a filehandle that got the same filehandle id
2320 as STDIN. This occurred because you closed STDIN previously.
2322 =item Final $ should be \$ or $name
2324 (F) You must now decide whether the final $ in a string was meant to be
2325 a literal dollar sign, or was meant to introduce a variable name that
2326 happens to be missing. So you have to put either the backslash or the
2329 =item flock() on closed filehandle %s
2331 (W closed) The filehandle you're attempting to flock() got itself closed
2332 some time before now. Check your control flow. flock() operates on
2333 filehandles. Are you attempting to call flock() on a dirhandle by the
2336 =item Format not terminated
2338 (F) A format must be terminated by a line with a solitary dot. Perl got
2339 to the end of your file without finding such a line.
2341 =item Format %s redefined
2343 (W redefine) You redefined a format. To suppress this warning, say
2346 no warnings 'redefine';
2347 eval "format NAME =...";
2350 =item Found = in conditional, should be ==
2360 (or something like that).
2362 =item %s found where operator expected
2364 (S syntax) The Perl lexer knows whether to expect a term or an operator.
2365 If it sees what it knows to be a term when it was expecting to see an
2366 operator, it gives you this warning. Usually it indicates that an
2367 operator or delimiter was omitted, such as a semicolon.
2369 =item gdbm store returned %d, errno %d, key "%s"
2371 (S) A warning from the GDBM_File extension that a store failed.
2373 =item gethostent not implemented
2375 (F) Your C library apparently doesn't implement gethostent(), probably
2376 because if it did, it'd feel morally obligated to return every hostname
2379 =item get%sname() on closed socket %s
2381 (W closed) You tried to get a socket or peer socket name on a closed
2382 socket. Did you forget to check the return value of your socket() call?
2384 =item getpwnam returned invalid UIC %#o for user "%s"
2386 (S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
2387 C<getpwnam> operator returned an invalid UIC.
2389 =item getsockopt() on closed socket %s
2391 (W closed) You tried to get a socket option on a closed socket. Did you
2392 forget to check the return value of your socket() call? See
2393 L<perlfunc/getsockopt>.
2395 =item given is experimental
2397 (S experimental::smartmatch) C<given> depends on smartmatch, which
2398 is experimental, so its behavior may change or even be removed
2399 in any future release of perl. See the explanation under
2400 L<perlsyn/Experimental Details on given and when>.
2402 =item Global symbol "%s" requires explicit package name (did you forget to
2405 (F) You've said "use strict" or "use strict vars", which indicates
2406 that all variables must either be lexically scoped (using "my" or "state"),
2407 declared beforehand using "our", or explicitly qualified to say
2408 which package the global variable is in (using "::").
2410 =item glob failed (%s)
2412 (S glob) Something went wrong with the external program(s) used
2413 for C<glob> and C<< <*.c> >>. Usually, this means that you supplied a C<glob>
2414 pattern that caused the external program to fail and exit with a
2415 nonzero status. If the message indicates that the abnormal exit
2416 resulted in a coredump, this may also mean that your csh (C shell)
2417 is broken. If so, you should change all of the csh-related variables
2418 in config.sh: If you have tcsh, make the variables refer to it as
2419 if it were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them
2420 all empty (except that C<d_csh> should be C<'undef'>) so that Perl will
2421 think csh is missing. In either case, after editing config.sh, run
2422 C<./Configure -S> and rebuild Perl.
2424 =item Glob not terminated
2426 (F) The lexer saw a left angle bracket in a place where it was expecting
2427 a term, so it's looking for the corresponding right angle bracket, and
2428 not finding it. Chances are you left some needed parentheses out
2429 earlier in the line, and you really meant a "less than".
2431 =item gmtime(%f) failed
2433 (W overflow) You called C<gmtime> with a number that it could not handle:
2434 too large, too small, or NaN. The returned value is C<undef>.
2436 =item gmtime(%f) too large
2438 (W overflow) You called C<gmtime> with a number that was larger than
2439 it can reliably handle and C<gmtime> probably returned the wrong
2440 date. This warning is also triggered with NaN (the special
2441 not-a-number value).
2443 =item gmtime(%f) too small
2445 (W overflow) You called C<gmtime> with a number that was smaller than
2446 it can reliably handle and C<gmtime> probably returned the wrong date.
2448 =item Got an error from DosAllocMem
2450 (P) An error peculiar to OS/2. Most probably you're using an obsolete
2451 version of Perl, and this should not happen anyway.
2453 =item goto must have label
2455 (F) Unlike with "next" or "last", you're not allowed to goto an
2456 unspecified destination. See L<perlfunc/goto>.
2458 =item Goto undefined subroutine%s
2460 (F) You tried to call a subroutine with C<goto &sub> syntax, but
2461 the indicated subroutine hasn't been defined, or if it was, it
2462 has since been undefined.
2464 =item Group name must start with a non-digit word character in regex; marked by
2465 S<<-- HERE> in m/%s/
2467 (F) Group names must follow the rules for perl identifiers, meaning
2468 they must start with a non-digit word character. A common cause of
2469 this error is using (?&0) instead of (?0). See L<perlre>.
2471 =item ()-group starts with a count
2473 (F) A ()-group started with a count. A count is supposed to follow
2474 something: a template character or a ()-group. See L<perlfunc/pack>.
2476 =item %s had compilation errors.
2478 (F) The final summary message when a C<perl -c> fails.
2480 =item Had to create %s unexpectedly
2482 (S internal) A routine asked for a symbol from a symbol table that ought
2483 to have existed already, but for some reason it didn't, and had to be
2484 created on an emergency basis to prevent a core dump.
2486 =item %s has too many errors
2488 (F) The parser has given up trying to parse the program after 10 errors.
2489 Further error messages would likely be uninformative.
2491 =item Hexadecimal float: exponent overflow
2493 (W overflow) The hexadecimal floating point has a larger exponent
2494 than the floating point supports.
2496 =item Hexadecimal float: exponent underflow
2498 (W overflow) The hexadecimal floating point has a smaller exponent
2499 than the floating point supports.
2501 =item Hexadecimal float: internal error (%s)
2503 (F) Something went horribly bad in hexadecimal float handling.
2505 =item Hexadecimal float: mantissa overflow
2507 (W overflow) The hexadecimal floating point literal had more bits in
2508 the mantissa (the part between the 0x and the exponent, also known as
2509 the fraction or the significand) than the floating point supports.
2511 =item Hexadecimal float: precision loss
2513 (W overflow) The hexadecimal floating point had internally more
2514 digits than could be output. This can be caused by unsupported
2515 long double formats, or by 64-bit integers not being available
2516 (needed to retrieve the digits under some configurations).
2518 =item Hexadecimal float: unsupported long double format
2520 (F) You have configured Perl to use long doubles but
2521 the internals of the long double format are unknown;
2522 therefore the hexadecimal float output is impossible.
2524 =item Hexadecimal number > 0xffffffff non-portable
2526 (W portable) The hexadecimal number you specified is larger than 2**32-1
2527 (4294967295) and therefore non-portable between systems. See
2528 L<perlport> for more on portability concerns.
2530 =item Identifier too long
2532 (F) Perl limits identifiers (names for variables, functions, etc.) to
2533 about 250 characters for simple names, and somewhat more for compound
2534 names (like C<$A::B>). You've exceeded Perl's limits. Future versions
2535 of Perl are likely to eliminate these arbitrary limitations.
2537 =item Ignoring zero length \N{} in character class in regex; marked by
2538 S<<-- HERE> in m/%s/
2540 (W regexp) Named Unicode character escapes (C<\N{...}>) may return a
2541 zero-length sequence. When such an escape is used in a character
2542 class its behavior is not well defined. Check that the correct
2543 escape has been used, and the correct charname handler is in scope.
2545 =item Illegal binary digit %s
2547 (F) You used a digit other than 0 or 1 in a binary number.
2549 =item Illegal binary digit %s ignored
2551 (W digit) You may have tried to use a digit other than 0 or 1 in a
2552 binary number. Interpretation of the binary number stopped before the
2555 =item Illegal character after '_' in prototype for %s : %s
2557 (W illegalproto) An illegal character was found in a prototype
2558 declaration. The '_' in a prototype must be followed by a ';',
2559 indicating the rest of the parameters are optional, or one of '@'
2560 or '%', since those two will accept 0 or more final parameters.
2562 =item Illegal character \%o (carriage return)
2564 (F) Perl normally treats carriage returns in the program text as it
2565 would any other whitespace, which means you should never see this error
2566 when Perl was built using standard options. For some reason, your
2567 version of Perl appears to have been built without this support. Talk
2568 to your Perl administrator.
2570 =item Illegal character in prototype for %s : %s
2572 (W illegalproto) An illegal character was found in a prototype declaration.
2573 Legal characters in prototypes are $, @, %, *, ;, [, ], &, \, and +.
2574 Perhaps you were trying to write a subroutine signature but didn't enable
2575 that feature first (C<use feature 'signatures'>), so your signature was
2576 instead interpreted as a bad prototype.
2578 =item Illegal declaration of anonymous subroutine
2580 (F) When using the C<sub> keyword to construct an anonymous subroutine,
2581 you must always specify a block of code. See L<perlsub>.
2583 =item Illegal declaration of subroutine %s
2585 (F) A subroutine was not declared correctly. See L<perlsub>.
2587 =item Illegal division by zero
2589 (F) You tried to divide a number by 0. Either something was wrong in
2590 your logic, or you need to put a conditional in to guard against
2593 =item Illegal hexadecimal digit %s ignored
2595 (W digit) You may have tried to use a character other than 0 - 9 or
2596 A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
2597 number stopped before the illegal character.
2599 =item Illegal modulus zero
2601 (F) You tried to divide a number by 0 to get the remainder. Most
2602 numbers don't take to this kindly.
2604 =item Illegal number of bits in vec
2606 (F) The number of bits in vec() (the third argument) must be a power of
2607 two from 1 to 32 (or 64, if your platform supports that).
2609 =item Illegal octal digit %s
2611 (F) You used an 8 or 9 in an octal number.
2613 =item Illegal octal digit %s ignored
2615 (W digit) You may have tried to use an 8 or 9 in an octal number.
2616 Interpretation of the octal number stopped before the 8 or 9.
2618 =item Illegal pattern in regex; marked by S<<-- HERE> in m/%s/
2620 (F) You wrote something like
2624 The C<"+"> is valid only when followed by digits, indicating a
2625 capturing group. See
2626 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
2628 =item Illegal suidscript
2630 (F) The script run under suidperl was somehow illegal.
2632 =item Illegal switch in PERL5OPT: -%c
2634 (X) The PERL5OPT environment variable may only be used to set the
2635 following switches: B<-[CDIMUdmtw]>.
2637 =item Illegal user-defined property name
2639 (F) You specified a Unicode-like property name in a regular expression
2640 pattern (using C<\p{}> or C<\P{}>) that Perl knows isn't an official
2641 Unicode property, and was likely meant to be a user-defined property
2642 name, but it can't be one of those, as they must begin with either C<In>
2643 or C<Is>. Check the spelling. See also
2644 L</Can't find Unicode property definition "%s">.
2646 =item Ill-formed CRTL environ value "%s"
2648 (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
2649 internal environ array, and encountered an element without the C<=>
2650 delimiter used to separate keys from values. The element is ignored.
2652 =item Ill-formed message in prime_env_iter: |%s|
2654 (W internal) A warning peculiar to VMS. Perl tried to read a logical
2655 name or CLI symbol definition when preparing to iterate over %ENV, and
2656 didn't see the expected delimiter between key and value, so the line was
2659 =item (in cleanup) %s
2661 (W misc) This prefix usually indicates that a DESTROY() method raised
2662 the indicated exception. Since destructors are usually called by the
2663 system at arbitrary points during execution, and often a vast number of
2664 times, the warning is issued only once for any number of failures that
2665 would otherwise result in the same message being repeated.
2667 Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
2668 also result in this warning. See L<perlcall/G_KEEPERR>.
2670 =item Incomplete expression within '(?[ ])' in regex; marked by S<<-- HERE>
2673 (F) There was a syntax error within the C<(?[ ])>. This can happen if the
2674 expression inside the construct was completely empty, or if there are
2675 too many or few operands for the number of operators. Perl is not smart
2676 enough to give you a more precise indication as to what is wrong.
2678 =item Inconsistent hierarchy during C3 merge of class '%s': merging failed on
2681 (F) The method resolution order (MRO) of the given class is not
2682 C3-consistent, and you have enabled the C3 MRO for this class. See the C3
2683 documentation in L<mro> for more information.
2685 =item Infinite recursion in regex
2687 (F) You used a pattern that references itself without consuming any input
2688 text. You should check the pattern to ensure that recursive patterns
2689 either consume text or fail.
2691 =item Initialization of state variables in list context currently forbidden
2693 (F) Currently the implementation of "state" only permits the
2694 initialization of scalar variables in scalar context. Re-write
2695 C<state ($a) = 42> as C<state $a = 42> to change from list to scalar
2696 context. Constructions such as C<state (@a) = foo()> will be
2697 supported in a future perl release.
2699 =item %%s[%s] in scalar context better written as $%s[%s]
2701 (W syntax) In scalar context, you've used an array index/value slice
2702 (indicated by %) to select a single element of an array. Generally
2703 it's better to ask for a scalar value (indicated by $). The difference
2704 is that C<$foo[&bar]> always behaves like a scalar, both in the value it
2705 returns and when evaluating its argument, while C<%foo[&bar]> provides
2706 a list context to its subscript, which can do weird things if you're
2707 expecting only one subscript. When called in list context, it also
2708 returns the index (what C<&bar> returns) in addition to the value.
2710 =item %%s{%s} in scalar context better written as $%s{%s}
2712 (W syntax) In scalar context, you've used a hash key/value slice
2713 (indicated by %) to select a single element of a hash. Generally it's
2714 better to ask for a scalar value (indicated by $). The difference
2715 is that C<$foo{&bar}> always behaves like a scalar, both in the value
2716 it returns and when evaluating its argument, while C<@foo{&bar}> and
2717 provides a list context to its subscript, which can do weird things
2718 if you're expecting only one subscript. When called in list context,
2719 it also returns the key in addition to the value.
2721 =item Insecure dependency in %s
2723 (F) You tried to do something that the tainting mechanism didn't like.
2724 The tainting mechanism is turned on when you're running setuid or
2725 setgid, or when you specify B<-T> to turn it on explicitly. The
2726 tainting mechanism labels all data that's derived directly or indirectly
2727 from the user, who is considered to be unworthy of your trust. If any
2728 such data is used in a "dangerous" operation, you get this error. See
2729 L<perlsec> for more information.
2731 =item Insecure directory in %s
2733 (F) You can't use system(), exec(), or a piped open in a setuid or
2734 setgid script if C<$ENV{PATH}> contains a directory that is writable by
2735 the world. Also, the PATH must not contain any relative directory.
2738 =item Insecure $ENV{%s} while running %s
2740 (F) You can't use system(), exec(), or a piped open in a setuid or
2741 setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
2742 C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
2743 supplied (or potentially supplied) by the user. The script must set
2744 the path to a known value, using trustworthy data. See L<perlsec>.
2746 =item Insecure user-defined property %s
2748 (F) Perl detected tainted data when trying to compile a regular
2749 expression that contains a call to a user-defined character property
2750 function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2751 See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
2753 =item Integer overflow in format string for %s
2755 (F) The indexes and widths specified in the format string of C<printf()>
2756 or C<sprintf()> are too large. The numbers must not overflow the size of
2757 integers for your architecture.
2759 =item Integer overflow in %s number
2761 (S overflow) The hexadecimal, octal or binary number you have specified
2762 either as a literal or as an argument to hex() or oct() is too big for
2763 your architecture, and has been converted to a floating point number.
2764 On a 32-bit architecture the largest hexadecimal, octal or binary number
2765 representable without overflow is 0xFFFFFFFF, 037777777777, or
2766 0b11111111111111111111111111111111 respectively. Note that Perl
2767 transparently promotes all numbers to a floating point representation
2768 internally--subject to loss of precision errors in subsequent
2771 =item Integer overflow in srand
2773 (S overflow) The number you have passed to srand is too big to fit
2774 in your architecture's integer representation. The number has been
2775 replaced with the largest integer supported (0xFFFFFFFF on 32-bit
2776 architectures). This means you may be getting less randomness than
2777 you expect, because different random seeds above the maximum will
2778 return the same sequence of random numbers.
2780 =item Integer overflow in version
2782 =item Integer overflow in version %d
2784 (W overflow) Some portion of a version initialization is too large for
2785 the size of integers for your architecture. This is not a warning
2786 because there is no rational reason for a version to try and use an
2787 element larger than typically 2**32. This is usually caused by trying
2788 to use some odd mathematical operation as a version, like 100/9.
2790 =item Internal disaster in regex; marked by S<<-- HERE> in m/%s/
2792 (P) Something went badly wrong in the regular expression parser.
2793 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2796 =item Internal inconsistency in tracking vforks
2798 (S) A warning peculiar to VMS. Perl keeps track of the number of times
2799 you've called C<fork> and C<exec>, to determine whether the current call
2800 to C<exec> should affect the current script or a subprocess (see
2801 L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
2802 Perl is making a guess and treating this C<exec> as a request to
2803 terminate the Perl script and execute the specified command.
2805 =item internal %<num>p might conflict with future printf extensions
2807 (S internal) Perl's internal routine that handles C<printf> and C<sprintf>
2808 formatting follows a slightly different set of rules when called from
2809 C or XS code. Specifically, formats consisting of digits followed
2810 by "p" (e.g., "%7p") are reserved for future use. If you see this
2811 message, then an XS module tried to call that routine with one such
2814 =item Internal urp in regex; marked by S<<-- HERE> in m/%s/
2816 (P) Something went badly awry in the regular expression parser. The
2817 S<<-- HERE> shows whereabouts in the regular expression the problem was
2820 =item %s (...) interpreted as function
2822 (W syntax) You've run afoul of the rule that says that any list operator
2823 followed by parentheses turns into a function, with all the list
2824 operators arguments found inside the parentheses. See
2825 L<perlop/Terms and List Operators (Leftward)>.
2827 =item In '(?...)', the '(' and '?' must be adjacent in regex;
2828 marked by S<<-- HERE> in m/%s/
2830 (F) The two-character sequence C<"(?"> in this context in a regular
2831 expression pattern should be an indivisible token, with nothing
2832 intervening between the C<"("> and the C<"?">, but you separated them
2835 =item Invalid %s attribute: %s
2837 (F) The indicated attribute for a subroutine or variable was not recognized
2838 by Perl or by a user-supplied handler. See L<attributes>.
2840 =item Invalid %s attributes: %s
2842 (F) The indicated attributes for a subroutine or variable were not
2843 recognized by Perl or by a user-supplied handler. See L<attributes>.
2845 =item Invalid character in charnames alias definition; marked by
2848 (F) You tried to create a custom alias for a character name, with
2849 the C<:alias> option to C<use charnames> and the specified character in
2850 the indicated name isn't valid. See L<charnames/CUSTOM ALIASES>.
2852 =item Invalid \0 character in %s for %s: %s\0%s
2854 (W syscalls) Embedded \0 characters in pathnames or other system call
2855 arguments produce a warning as of 5.20. The parts after the \0 were
2856 formerly ignored by system calls.
2858 =item Invalid character in \N{...}; marked by S<<-- HERE> in \N{%s}
2860 (F) Only certain characters are valid for character names. The
2861 indicated one isn't. See L<charnames/CUSTOM ALIASES>.
2863 =item Invalid conversion in %s: "%s"
2865 (W printf) Perl does not understand the given format conversion. See
2866 L<perlfunc/sprintf>.
2868 =item Invalid escape in the specified encoding in regex; marked by
2869 S<<-- HERE> in m/%s/
2871 (W regexp)(F) The numeric escape (for example C<\xHH>) of value < 256
2872 didn't correspond to a single character through the conversion
2873 from the encoding specified by the encoding pragma.
2874 The escape was replaced with REPLACEMENT CHARACTER (U+FFFD)
2875 instead, except within S<C<(?[ ])>>, where it is a fatal error.
2876 The S<<-- HERE> shows whereabouts in the regular expression the
2877 escape was discovered.
2879 =item Invalid hexadecimal number in \N{U+...}
2881 =item Invalid hexadecimal number in \N{U+...} in regex; marked by
2882 S<<-- HERE> in m/%s/
2884 (F) The character constant represented by C<...> is not a valid hexadecimal
2885 number. Either it is empty, or you tried to use a character other than
2886 0 - 9 or A - F, a - f in a hexadecimal number.
2888 =item Invalid module name %s with -%c option: contains single ':'
2890 (F) The module argument to perl's B<-m> and B<-M> command-line options
2891 cannot contain single colons in the module name, but only in the
2892 arguments after "=". In other words, B<-MFoo::Bar=:baz> is ok, but
2893 B<-MFoo:Bar=baz> is not.
2895 =item Invalid mro name: '%s'
2897 (F) You tried to C<mro::set_mro("classname", "foo")> or C<use mro 'foo'>,
2898 where C<foo> is not a valid method resolution order (MRO). Currently,
2899 the only valid ones supported are C<dfs> and C<c3>, unless you have loaded
2900 a module that is a MRO plugin. See L<mro> and L<perlmroapi>.
2902 =item Invalid negative number (%s) in chr
2904 (W utf8) You passed a negative number to C<chr>. Negative numbers are
2905 not valid character numbers, so it returns the Unicode replacement
2908 =item Invalid number '%s' for -C option.
2910 (F) You supplied a number to the -C option that either has extra leading
2911 zeroes or overflows perl's unsigned integer representation.
2913 =item invalid option -D%c, use -D'' to see choices
2915 (S debugging) Perl was called with invalid debugger flags. Call perl
2916 with the B<-D> option with no flags to see the list of acceptable values.
2917 See also L<perlrun/-Dletters>.
2919 =item Invalid quantifier in {,} in regex; marked by S<<-- HERE> in m/%s/
2921 (F) The pattern looks like a {min,max} quantifier, but the min or max
2922 could not be parsed as a valid number - either it has leading zeroes,
2923 or it represents too big a number to cope with. The S<<-- HERE> shows
2924 where in the regular expression the problem was discovered. See L<perlre>.
2926 =item Invalid [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2928 (F) The range specified in a character class had a minimum character
2929 greater than the maximum character. One possibility is that you forgot the
2930 C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
2931 up to C<ff>. The S<<-- HERE> shows whereabouts in the regular expression the
2932 problem was discovered. See L<perlre>.
2934 =item Invalid range "%s" in transliteration operator
2936 (F) The range specified in the tr/// or y/// operator had a minimum
2937 character greater than the maximum character. See L<perlop>.
2939 =item Invalid separator character %s in attribute list
2941 (F) Something other than a colon or whitespace was seen between the
2942 elements of an attribute list. If the previous attribute had a
2943 parenthesised parameter list, perhaps that list was terminated too soon.
2946 =item Invalid separator character %s in PerlIO layer specification %s
2948 (W layer) When pushing layers onto the Perl I/O system, something other
2949 than a colon or whitespace was seen between the elements of a layer list.
2950 If the previous attribute had a parenthesised parameter list, perhaps that
2951 list was terminated too soon.
2953 =item Invalid strict version format (%s)
2955 (F) A version number did not meet the "strict" criteria for versions.
2956 A "strict" version number is a positive decimal number (integer or
2957 decimal-fraction) without exponentiation or else a dotted-decimal
2958 v-string with a leading 'v' character and at least three components.
2959 The parenthesized text indicates which criteria were not met.
2960 See the L<version> module for more details on allowed version formats.
2962 =item Invalid type '%s' in %s
2964 (F) The given character is not a valid pack or unpack type.
2965 See L<perlfunc/pack>.
2967 (W) The given character is not a valid pack or unpack type but used to be
2970 =item Invalid version format (%s)
2972 (F) A version number did not meet the "lax" criteria for versions.
2973 A "lax" version number is a positive decimal number (integer or
2974 decimal-fraction) without exponentiation or else a dotted-decimal
2975 v-string. If the v-string has fewer than three components, it
2976 must have a leading 'v' character. Otherwise, the leading 'v' is
2977 optional. Both decimal and dotted-decimal versions may have a
2978 trailing "alpha" component separated by an underscore character
2979 after a fractional or dotted-decimal component. The parenthesized
2980 text indicates which criteria were not met. See the L<version> module
2981 for more details on allowed version formats.
2983 =item Invalid version object
2985 (F) The internal structure of the version object was invalid.
2986 Perhaps the internals were modified directly in some way or
2987 an arbitrary reference was blessed into the "version" class.
2989 =item In '(*VERB...)', the '(' and '*' must be adjacent in regex;
2990 marked by S<<-- HERE> in m/%s/
2992 (F) The two-character sequence C<"(*"> in
2993 this context in a regular expression pattern should be an
2994 indivisible token, with nothing intervening between the C<"(">
2995 and the C<"*">, but you separated them.
2997 =item ioctl is not implemented
2999 (F) Your machine apparently doesn't implement ioctl(), which is pretty
3000 strange for a machine that supports C.
3002 =item ioctl() on unopened %s
3004 (W unopened) You tried ioctl() on a filehandle that was never opened.
3005 Check your control flow and number of arguments.
3007 =item IO layers (like '%s') unavailable
3009 (F) Your Perl has not been configured to have PerlIO, and therefore
3010 you cannot use IO layers. To have PerlIO, Perl must be configured
3013 =item IO::Socket::atmark not implemented on this architecture
3015 (F) Your machine doesn't implement the sockatmark() functionality,
3016 neither as a system call nor an ioctl call (SIOCATMARK).
3018 =item '%s' is an unknown bound type in regex; marked by S<<-- HERE> in m/%s/
3020 (F) You used C<\b{...}> or C<\B{...}> and the C<...> is not known to
3021 Perl. The current valid ones are given in
3022 L<perlrebackslash/\b{}, \b, \B{}, \B>.
3024 =item %s() is deprecated on :utf8 handles
3026 (W deprecated) The sysread(), recv(), syswrite() and send() operators are
3027 deprecated on handles that have the C<:utf8> layer, either explicitly, or
3028 implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
3030 Both sysread() and recv() currently use only the C<:utf8> flag for the stream,
3031 ignoring the actual layers. Since sysread() and recv() do no UTF-8
3032 validation they can end up creating invalidly encoded scalars.
3034 Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise ignoring
3035 any layers. If the flag is set, both write the value UTF-8 encoded, even if
3036 the layer is some different encoding, such as the example above.
3038 Ideally, all of these operators would completely ignore the C<:utf8> state,
3039 working only with bytes, but this would result in silently breaking existing
3040 code. To avoid this a future version of perl will throw an exception when
3041 any of sysread(), recv(), syswrite() or send() are called on handle with the
3044 =item "%s" is more clearly written simply as "%s" in regex; marked by S<<-- HERE> in m/%s/
3046 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
3048 You specified a character that has the given plainer way of writing it,
3049 and which is also portable to platforms running with different character
3052 =item $* is no longer supported
3054 (D deprecated, syntax) The special variable C<$*>, deprecated in older
3055 perls, has been removed as of 5.10.0 and is no longer supported. In
3056 previous versions of perl the use of C<$*> enabled or disabled multi-line
3057 matching within a string.
3059 Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
3060 modifiers. You can enable C</m> for a lexical scope (even a whole file)
3061 with C<use re '/m'>. (In older versions: when C<$*> was set to a true value
3062 then all regular expressions behaved as if they were written using C</m>.)
3064 =item $# is no longer supported
3066 (D deprecated, syntax) The special variable C<$#>, deprecated in older
3067 perls, has been removed as of 5.10.0 and is no longer supported. You
3068 should use the printf/sprintf functions instead.
3070 =item '%s' is not a code reference
3072 (W overload) The second (fourth, sixth, ...) argument of
3073 overload::constant needs to be a code reference. Either
3074 an anonymous subroutine, or a reference to a subroutine.
3076 =item '%s' is not an overloadable type
3078 (W overload) You tried to overload a constant type the overload package is
3081 =item -i used with no filenames on the command line, reading from STDIN
3083 (S inplace) The C<-i> option was passed on the command line, indicating
3084 that the script is intended to edit files in place, but no files were
3085 given. This is usually a mistake, since editing STDIN in place doesn't
3086 make sense, and can be confusing because it can make perl look like
3087 it is hanging when it is really just trying to read from STDIN. You
3088 should either pass a filename to edit, or remove C<-i> from the command
3089 line. See L<perlrun> for more details.
3091 =item Junk on end of regexp in regex m/%s/
3093 (P) The regular expression parser is confused.
3095 =item Label not found for "last %s"
3097 (F) You named a loop to break out of, but you're not currently in a loop
3098 of that name, not even if you count where you were called from. See
3101 =item Label not found for "next %s"
3103 (F) You named a loop to continue, but you're not currently in a loop of
3104 that name, not even if you count where you were called from. See
3107 =item Label not found for "redo %s"
3109 (F) You named a loop to restart, but you're not currently in a loop of
3110 that name, not even if you count where you were called from. See
3113 =item leaving effective %s failed
3115 (F) While under the C<use filetest> pragma, switching the real and
3116 effective uids or gids failed.
3118 =item length/code after end of string in unpack
3120 (F) While unpacking, the string buffer was already used up when an unpack
3121 length/code combination tried to obtain more data. This results in
3122 an undefined value for the length. See L<perlfunc/pack>.
3124 =item length() used on %s (did you mean "scalar(%s)"?)
3126 (W syntax) You used length() on either an array or a hash when you
3127 probably wanted a count of the items.
3129 Array size can be obtained by doing:
3133 The number of items in a hash can be obtained by doing:
3137 =item Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
3139 (F) An extension is attempting to insert text into the current parse
3140 (using L<lex_stuff_pvn|perlapi/lex_stuff_pvn> or similar), but tried to insert a character that
3141 couldn't be part of the current input. This is an inherent pitfall
3142 of the stuffing mechanism, and one of the reasons to avoid it. Where
3143 it is necessary to stuff, stuffing only plain ASCII is recommended.
3145 =item Lexing code internal error (%s)
3147 (F) Lexing code supplied by an extension violated the lexer's API in a
3150 =item listen() on closed socket %s
3152 (W closed) You tried to do a listen on a closed socket. Did you forget
3153 to check the return value of your socket() call? See
3156 =item List form of piped open not implemented
3158 (F) On some platforms, notably Windows, the three-or-more-arguments
3159 form of C<open> does not support pipes, such as C<open($pipe, '|-', @args)>.
3160 Use the two-argument C<open($pipe, '|prog arg1 arg2...')> form instead.
3162 =item %s: loadable library and perl binaries are mismatched (got handshake key %p, needed %p)
3164 (P) A dynamic loading library C<.so> or C<.dll> was being loaded into the
3165 process that was built against a different build of perl than the
3166 said library was compiled against. Reinstalling the XS module will
3167 likely fix this error.
3169 =item Locale '%s' may not work well.%s
3171 (W locale) You are using the named locale, which is a non-UTF-8 one, and
3172 which perl has determined is not fully compatible with what it can
3173 handle. The second C<%s> gives a reason.
3175 By far the most common reason is that the locale has characters in it
3176 that are represented by more than one byte. The only such locales that
3177 Perl can handle are the UTF-8 locales. Most likely the specified locale
3178 is a non-UTF-8 one for an East Asian language such as Chinese or
3179 Japanese. If the locale is a superset of ASCII, the ASCII portion of it
3182 Some essentially obsolete locales that aren't supersets of ASCII, mainly
3183 those in ISO 646 or other 7-bit locales, such as ASMO 449, can also have
3184 problems, depending on what portions of the ASCII character set get
3185 changed by the locale and are also used by the program.
3186 The warning message lists the determinable conflicting characters.
3188 Note that not all incompatibilities are found.
3190 If this happens to you, there's not much you can do except switch to use a
3191 different locale or use L<Encode> to translate from the locale into
3192 UTF-8; if that's impracticable, you have been warned that some things
3195 This message is output once each time a bad locale is switched into
3196 within the scope of C<S<use locale>>, or on the first possibly-affected
3197 operation if the C<S<use locale>> inherits a bad one. It is not raised
3198 for any operations from the L<POSIX> module.
3200 =item localtime(%f) failed
3202 (W overflow) You called C<localtime> with a number that it could not handle:
3203 too large, too small, or NaN. The returned value is C<undef>.
3205 =item localtime(%f) too large
3207 (W overflow) You called C<localtime> with a number that was larger
3208 than it can reliably handle and C<localtime> probably returned the
3209 wrong date. This warning is also triggered with NaN (the special
3210 not-a-number value).
3212 =item localtime(%f) too small
3214 (W overflow) You called C<localtime> with a number that was smaller
3215 than it can reliably handle and C<localtime> probably returned the
3218 =item Lookbehind longer than %d not implemented in regex m/%s/
3220 (F) There is currently a limit on the length of string which lookbehind can
3221 handle. This restriction may be eased in a future release.
3223 =item Lost precision when %s %f by 1
3225 (W imprecision) The value you attempted to increment or decrement by one
3226 is too large for the underlying floating point representation to store
3227 accurately, hence the target of C<++> or C<--> is unchanged. Perl issues this
3228 warning because it has already switched from integers to floating point
3229 when values are too large for integers, and now even floating point is
3230 insufficient. You may wish to switch to using L<Math::BigInt> explicitly.
3232 =item lstat() on filehandle%s
3234 (W io) You tried to do an lstat on a filehandle. What did you mean
3235 by that? lstat() makes sense only on filenames. (Perl did a fstat()
3236 instead on the filehandle.)
3238 =item lvalue attribute %s already-defined subroutine
3240 (W misc) Although L<attributes.pm|attributes> allows this, turning the lvalue
3241 attribute on or off on a Perl subroutine that is already defined
3242 does not always work properly. It may or may not do what you
3243 want, depending on what code is inside the subroutine, with exact
3244 details subject to change between Perl versions. Only do this
3245 if you really know what you are doing.
3247 =item lvalue attribute ignored after the subroutine has been defined
3249 (W misc) Using the C<:lvalue> declarative syntax to make a Perl
3250 subroutine an lvalue subroutine after it has been defined is
3251 not permitted. To make the subroutine an lvalue subroutine,
3252 add the lvalue attribute to the definition, or put the C<sub
3253 foo :lvalue;> declaration before the definition.
3255 See also L<attributes.pm|attributes>.
3257 =item Magical list constants are not supported
3259 (F) You assigned a magical array to a stash element, and then tried
3260 to use the subroutine from the same slot. You are asking Perl to do
3261 something it cannot do, details subject to change between Perl versions.
3263 =item Malformed integer in [] in pack
3265 (F) Between the brackets enclosing a numeric repeat count only digits
3266 are permitted. See L<perlfunc/pack>.
3268 =item Malformed integer in [] in unpack
3270 (F) Between the brackets enclosing a numeric repeat count only digits
3271 are permitted. See L<perlfunc/pack>.
3273 =item Malformed PERLLIB_PREFIX
3275 (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
3282 with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
3283 a builtin library search path, prefix2 is substituted. The error may
3284 appear if components are not found, or are too long. See
3285 "PERLLIB_PREFIX" in L<perlos2>.
3287 =item Malformed prototype for %s: %s
3289 (F) You tried to use a function with a malformed prototype. The
3290 syntax of function prototypes is given a brief compile-time check for
3291 obvious errors like invalid characters. A more rigorous check is run
3292 when the function is called.
3293 Perhaps the function's author was trying to write a subroutine signature
3294 but didn't enable that feature first (C<use feature 'signatures'>),
3295 so the signature was instead interpreted as a bad prototype.
3297 =item Malformed UTF-8 character (%s)
3299 (S utf8)(F) Perl detected a string that didn't comply with UTF-8
3300 encoding rules, even though it had the UTF8 flag on.
3302 One possible cause is that you set the UTF8 flag yourself for data that
3303 you thought to be in UTF-8 but it wasn't (it was for example legacy
3304 8-bit data). To guard against this, you can use Encode::decode_utf8.
3306 If you use the C<:encoding(UTF-8)> PerlIO layer for input, invalid byte
3307 sequences are handled gracefully, but if you use C<:utf8>, the flag is
3308 set without validating the data, possibly resulting in this error
3311 See also L<Encode/"Handling Malformed Data">.
3313 =item Malformed UTF-8 character immediately after '%s'
3315 (F) You said C<use utf8>, but the program file doesn't comply with UTF-8
3316 encoding rules. The message prints out the properly encoded characters
3317 just before the first bad one. If C<utf8> warnings are enabled, a
3318 warning is generated that gives more details about the type of
3321 =item Malformed UTF-8 returned by \N{%s} immediately after '%s'
3323 (F) The charnames handler returned malformed UTF-8.
3325 =item Malformed UTF-8 string in '%c' format in unpack
3327 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3328 rules and perl was unable to guess how to make more progress.
3330 =item Malformed UTF-8 string in pack
3332 (F) You tried to pack something that didn't comply with UTF-8 encoding
3333 rules and perl was unable to guess how to make more progress.
3335 =item Malformed UTF-8 string in unpack
3337 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3338 rules and perl was unable to guess how to make more progress.
3340 =item Malformed UTF-16 surrogate
3342 (F) Perl thought it was reading UTF-16 encoded character data but while
3343 doing it Perl met a malformed Unicode surrogate.
3345 =item Mandatory parameter follows optional parameter
3347 (F) In a subroutine signature, you wrote something like "$a = undef,
3348 $b", making an earlier parameter optional and a later one mandatory.
3349 Parameters are filled from left to right, so it's impossible for the
3350 caller to omit an earlier one and pass a later one. If you want to act
3351 as if the parameters are filled from right to left, declare the rightmost
3352 optional and then shuffle the parameters around in the subroutine's body.
3354 =item Matched non-Unicode code point 0x%X against Unicode property; may
3357 (S non_unicode) Perl allows strings to contain a superset of
3358 Unicode code points; each code point may be as large as what is storable
3359 in an unsigned integer on your system, but these may not be accepted by
3360 other languages/systems. This message occurs when you matched a string
3361 containing such a code point against a regular expression pattern, and
3362 the code point was matched against a Unicode property, C<\p{...}> or
3363 C<\P{...}>. Unicode properties are only defined on Unicode code points,
3364 so the result of this match is undefined by Unicode, but Perl (starting
3365 in v5.20) treats non-Unicode code points as if they were typical
3366 unassigned Unicode ones, and matched this one accordingly. Whether a
3367 given property matches these code points or not is specified in
3368 L<perluniprops/Properties accessible through \p{} and \P{}>.
3370 This message is suppressed (unless it has been made fatal) if it is
3371 immaterial to the results of the match if the code point is Unicode or
3372 not. For example, the property C<\p{ASCII_Hex_Digit}> only can match
3373 the 22 characters C<[0-9A-Fa-f]>, so obviously all other code points,
3374 Unicode or not, won't match it. (And C<\P{ASCII_Hex_Digit}> will match
3375 every code point except these 22.)
3377 Getting this message indicates that the outcome of the match arguably
3378 should have been the opposite of what actually happened. If you think
3379 that is the case, you may wish to make the C<non_unicode> warnings
3380 category fatal; if you agree with Perl's decision, you may wish to turn
3383 See L<perlunicode/Beyond Unicode code points> for more information.
3385 =item %s matches null string many times in regex; marked by S<<-- HERE> in
3388 (W regexp) The pattern you've specified would be an infinite loop if the
3389 regular expression engine didn't specifically check for that. The S<<-- HERE>
3390 shows whereabouts in the regular expression the problem was discovered.
3393 =item Maximal count of pending signals (%u) exceeded
3395 (F) Perl aborted due to too high a number of signals pending. This
3396 usually indicates that your operating system tried to deliver signals
3397 too fast (with a very high priority), starving the perl process from
3398 resources it would need to reach a point where it can process signals
3399 safely. (See L<perlipc/"Deferred Signals (Safe Signals)">.)
3401 =item "%s" may clash with future reserved word
3403 (W) This warning may be due to running a perl5 script through a perl4
3404 interpreter, especially if the word that is being warned about is
3407 =item '%' may not be used in pack
3409 (F) You can't pack a string by supplying a checksum, because the
3410 checksumming process loses information, and you can't go the other way.
3411 See L<perlfunc/unpack>.
3413 =item Method for operation %s not found in package %s during blessing
3415 (F) An attempt was made to specify an entry in an overloading table that
3416 doesn't resolve to a valid subroutine. See L<overload>.
3418 =item Method %s not permitted
3422 =item Might be a runaway multi-line %s string starting on line %d
3424 (S) An advisory indicating that the previous error may have been caused
3425 by a missing delimiter on a string or pattern, because it eventually
3426 ended earlier on the current line.
3428 =item Misplaced _ in number
3430 (W syntax) An underscore (underbar) in a numeric constant did not
3431 separate two digits.
3433 =item Missing argument in %s
3435 (W missing) You called a function with fewer arguments than other
3436 arguments you supplied indicated would be needed.
3438 Currently only emitted when a printf-type format required more
3439 arguments than were supplied, but might be used in the future for
3440 other cases where we can statically determine that arguments to
3441 functions are missing, e.g. for the L<perlfunc/pack> function.
3443 =item Missing argument to -%c
3445 (F) The argument to the indicated command line switch must follow
3446 immediately after the switch, without intervening spaces.
3448 =item Missing braces on \N{}
3450 =item Missing braces on \N{} in regex; marked by S<<-- HERE> in m/%s/
3452 (F) Wrong syntax of character name literal C<\N{charname}> within
3453 double-quotish context. This can also happen when there is a space
3454 (or comment) between the C<\N> and the C<{> in a regex with the C</x> modifier.
3455 This modifier does not change the requirement that the brace immediately
3458 =item Missing braces on \o{}
3460 (F) A C<\o> must be followed immediately by a C<{> in double-quotish context.
3462 =item Missing comma after first argument to %s function
3464 (F) While certain functions allow you to specify a filehandle or an
3465 "indirect object" before the argument list, this ain't one of them.
3467 =item Missing command in piped open
3469 (W pipe) You used the C<open(FH, "| command")> or
3470 C<open(FH, "command |")> construction, but the command was missing or
3473 =item Missing control char name in \c
3475 (F) A double-quoted string ended with "\c", without the required control
3478 =item Missing ']' in prototype for %s : %s
3480 (W illegalproto) A grouping was started with C<[> but never closed with C<]>.
3482 =item Missing name in "%s sub"
3484 (F) The syntax for lexically scoped subroutines requires that
3485 they have a name with which they can be found.
3487 =item Missing $ on loop variable
3489 (F) Apparently you've been programming in B<csh> too much. Variables
3490 are always mentioned with the $ in Perl, unlike in the shells, where it
3491 can vary from one line to the next.
3493 =item (Missing operator before %s?)
3495 (S syntax) This is an educated guess made in conjunction with the message
3496 "%s found where operator expected". Often the missing operator is a comma.
3498 =item Missing or undefined argument to require
3500 (F) You tried to call require with no argument or with an undefined
3501 value as an argument. Require expects either a package name or a
3502 file-specification as an argument. See L<perlfunc/require>.
3504 =item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
3506 (F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
3508 =item Missing right brace on \N{}
3510 =item Missing right brace on \N{} or unescaped left brace after \N
3512 (F) C<\N> has two meanings.
3514 The traditional one has it followed by a name enclosed in braces,
3515 meaning the character (or sequence of characters) given by that
3516 name. Thus C<\N{ASTERISK}> is another way of writing C<*>, valid in both
3517 double-quoted strings and regular expression patterns. In patterns,
3518 it doesn't have the meaning an unescaped C<*> does.
3520 Starting in Perl 5.12.0, C<\N> also can have an additional meaning (only)
3521 in patterns, namely to match a non-newline character. (This is short
3522 for C<[^\n]>, and like C<.> but is not affected by the C</s> regex modifier.)
3524 This can lead to some ambiguities. When C<\N> is not followed immediately
3525 by a left brace, Perl assumes the C<[^\n]> meaning. Also, if the braces
3526 form a valid quantifier such as C<\N{3}> or C<\N{5,}>, Perl assumes that this
3527 means to match the given quantity of non-newlines (in these examples,
3528 3; and 5 or more, respectively). In all other case, where there is a
3529 C<\N{> and a matching C<}>, Perl assumes that a character name is desired.
3531 However, if there is no matching C<}>, Perl doesn't know if it was
3532 mistakenly omitted, or if C<[^\n]{> was desired, and raises this error.
3533 If you meant the former, add the right brace; if you meant the latter,
3534 escape the brace with a backslash, like so: C<\N\{>
3536 =item Missing right curly or square bracket
3538 (F) The lexer counted more opening curly or square brackets than closing
3539 ones. As a general rule, you'll find it's missing near the place you
3542 =item (Missing semicolon on previous line?)
3544 (S syntax) This is an educated guess made in conjunction with the message
3545 "%s found where operator expected". Don't automatically put a semicolon on
3546 the previous line just because you saw this message.
3548 =item Modification of a read-only value attempted
3550 (F) You tried, directly or indirectly, to change the value of a
3551 constant. You didn't, of course, try "2 = 1", because the compiler
3552 catches that. But an easy way to do the same thing is:
3554 sub mod { $_[0] = 1 }
3557 Another way is to assign to a substr() that's off the end of the string.
3559 Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
3560 is aliased to a constant in the look I<LIST>:
3563 foreach my $n ($x, 2) {
3564 $n *= 2; # modifies the $x, but fails on attempt to
3567 =item Modification of non-creatable array value attempted, %s
3569 (F) You tried to make an array value spring into existence, and the
3570 subscript was probably negative, even counting from end of the array
3573 =item Modification of non-creatable hash value attempted, %s
3575 (P) You tried to make a hash value spring into existence, and it
3576 couldn't be created for some peculiar reason.
3578 =item Module name must be constant
3580 (F) Only a bare module name is allowed as the first argument to a "use".
3582 =item Module name required with -%c option
3584 (F) The C<-M> or C<-m> options say that Perl should load some module, but
3585 you omitted the name of the module. Consult L<perlrun> for full details
3586 about C<-M> and C<-m>.
3588 =item More than one argument to '%s' open
3590 (F) The C<open> function has been asked to open multiple files. This
3591 can happen if you are trying to open a pipe to a command that takes a
3592 list of arguments, but have forgotten to specify a piped open mode.
3593 See L<perlfunc/open> for details.
3595 =item mprotect for COW string %p %u failed with %d
3597 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3598 L<perlguts/"Copy on Write">), but a shared string buffer
3599 could not be made read-only.
3601 =item mprotect for %p %u failed with %d
3603 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see L<perlhacktips>),
3604 but an op tree could not be made read-only.
3606 =item mprotect RW for COW string %p %u failed with %d
3608 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3609 L<perlguts/"Copy on Write">), but a read-only shared string
3610 buffer could not be made mutable.
3612 =item mprotect RW for %p %u failed with %d
3614 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see
3615 L<perlhacktips>), but a read-only op tree could not be made
3616 mutable before freeing the ops.
3618 =item msg%s not implemented
3620 (F) You don't have System V message IPC on your system.
3622 =item Multidimensional syntax %s not supported
3624 (W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
3625 They're written like C<$foo[1][2][3]>, as in C.
3627 =item '/' must follow a numeric type in unpack
3629 (F) You had an unpack template that contained a '/', but this did not
3630 follow some unpack specification producing a numeric value.
3631 See L<perlfunc/pack>.
3633 =item %s must not be a named sequence in transliteration operator
3635 (F) Transliteration (C<tr///> and C<y///>) transliterates individual
3636 characters. But a named sequence by definition is more than an
3637 individual charater, and hence doing this operation on it doesn't make
3640 =item "my sub" not yet implemented
3642 (F) Lexically scoped subroutines are not yet implemented. Don't try
3645 =item "my" subroutine %s can't be in a package
3647 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
3648 sense to try to declare one with a package qualifier on the front.
3650 =item "my %s" used in sort comparison
3652 (W syntax) The package variables $a and $b are used for sort comparisons.
3653 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
3654 sort comparison block, and the variable had earlier been declared as a
3655 lexical variable. Either qualify the sort variable with the package
3656 name, or rename the lexical variable.
3658 =item "my" variable %s can't be in a package
3660 (F) Lexically scoped variables aren't in a package, so it doesn't make
3661 sense to try to declare one with a package qualifier on the front. Use
3662 local() if you want to localize a package variable.
3664 =item Name "%s::%s" used only once: possible typo
3666 (W once) Typographical errors often show up as unique variable
3667 names. If you had a good reason for having a unique name, then
3668 just mention it again somehow to suppress the message. The C<our>
3669 declaration is also provided for this purpose.
3671 NOTE: This warning detects package symbols that have been used
3672 only once. This means lexical variables will never trigger this
3673 warning. It also means that all of the package variables $c, @c,
3674 %c, as well as *c, &c, sub c{}, c(), and c (the filehandle or
3675 format) are considered the same; if a program uses $c only once
3676 but also uses any of the others it will not trigger this warning.
3677 Symbols beginning with an underscore and symbols using special
3678 identifiers (q.v. L<perldata>) are exempt from this warning.
3680 =item Need exactly 3 octal digits in regex; marked by S<<-- HERE> in m/%s/
3682 (F) Within S<C<(?[ ])>>, all constants interpreted as octal need to be
3683 exactly 3 digits long. This helps catch some ambiguities. If your
3684 constant is too short, add leading zeros, like
3686 (?[ [ \078 ] ]) # Syntax error!
3687 (?[ [ \0078 ] ]) # Works
3688 (?[ [ \007 8 ] ]) # Clearer
3690 The maximum number this construct can express is C<\777>. If you
3691 need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes> instead. If you meant
3692 two separate things, you need to separate them:
3694 (?[ [ \7776 ] ]) # Syntax error!
3695 (?[ [ \o{7776} ] ]) # One meaning
3696 (?[ [ \777 6 ] ]) # Another meaning
3697 (?[ [ \777 \006 ] ]) # Still another
3699 =item Negative '/' count in unpack
3701 (F) The length count obtained from a length/code unpack operation was
3702 negative. See L<perlfunc/pack>.
3704 =item Negative length
3706 (F) You tried to do a read/write/send/recv operation with a buffer
3707 length that is less than 0. This is difficult to imagine.
3709 =item Negative offset to vec in lvalue context
3711 (F) When C<vec> is called in an lvalue context, the second argument must be
3712 greater than or equal to zero.
3714 =item Negative repeat count does nothing
3716 (W numeric) You tried to execute the
3717 L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
3718 times, which doesn't make sense.
3720 =item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
3722 (F) You can't quantify a quantifier without intervening parentheses.
3723 So things like ** or +* or ?* are illegal. The S<<-- HERE> shows
3724 whereabouts in the regular expression the problem was discovered.
3726 Note that the minimal matching quantifiers, C<*?>, C<+?>, and
3727 C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
3729 =item %s never introduced
3731 (S internal) The symbol in question was declared but somehow went out of
3732 scope before it could possibly have been used.
3734 =item next::method/next::can/maybe::next::method cannot find enclosing method
3736 (F) C<next::method> needs to be called within the context of a
3737 real method in a real package, and it could not find such a context.
3740 =item \N in a character class must be a named character: \N{...} in regex;
3741 marked by S<<-- HERE> in m/%s/
3743 (F) The new (as of Perl 5.12) meaning of C<\N> as C<[^\n]> is not valid in a
3744 bracketed character class, for the same reason that C<.> in a character
3745 class loses its specialness: it matches almost everything, which is
3746 probably not what you want.
3748 =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/
3750 (F) Named Unicode character escapes (C<\N{...}>) may return a
3751 multi-character sequence. Even though a character class is
3752 supposed to match just one character of input, perl will match the
3753 whole thing correctly, except when the class is inverted (C<[^...]>),
3754 or the escape is the beginning or final end point of a range. The
3755 mathematically logical behavior for what matches when inverting
3756 is very different from what people expect, so we have decided to
3757 forbid it. Similarly unclear is what should be generated when the
3758 C<\N{...}> is used as one of the end points of the range, such as in
3760 [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]
3762 What is meant here is unclear, as the C<\N{...}> escape is a sequence
3763 of code points, so this is made an error.
3765 =item \N{NAME} must be resolved by the lexer in regex; marked by
3766 S<<-- HERE> in m/%s/
3768 (F) When compiling a regex pattern, an unresolved named character or
3769 sequence was encountered. This can happen in any of several ways that
3770 bypass the lexer, such as using single-quotish context, or an extra
3771 backslash in double-quotish:
3773 $re = '\N{SPACE}'; # Wrong!
3774 $re = "\\N{SPACE}"; # Wrong!
3777 Instead, use double-quotes with a single backslash:
3779 $re = "\N{SPACE}"; # ok
3782 The lexer can be bypassed as well by creating the pattern from smaller
3786 /${re}{SPACE}/; # Wrong!
3788 It's not a good idea to split a construct in the middle like this, and
3789 it doesn't work here. Instead use the solution above.
3791 Finally, the message also can happen under the C</x> regex modifier when the
3792 C<\N> is separated by spaces from the C<{>, in which case, remove the spaces.
3794 /\N {SPACE}/x; # Wrong!
3797 =item No %s allowed while running setuid
3799 (F) Certain operations are deemed to be too insecure for a setuid or
3800 setgid script to even be allowed to attempt. Generally speaking there
3801 will be another way to do what you want that is, if not secure, at least
3802 securable. See L<perlsec>.
3804 =item No code specified for -%c
3806 (F) Perl's B<-e> and B<-E> command-line options require an argument. If
3807 you want to run an empty program, pass the empty string as a separate
3808 argument or run a program consisting of a single 0 or 1:
3814 =item No comma allowed after %s
3816 (F) A list operator that has a filehandle or "indirect object" is
3817 not allowed to have a comma between that and the following arguments.
3818 Otherwise it'd be just another one of the arguments.
3820 One possible cause for this is that you expected to have imported
3821 a constant to your name space with B<use> or B<import> while no such
3822 importing took place, it may for example be that your operating
3823 system does not support that particular constant. Hopefully you did
3824 use an explicit import list for the constants you expect to see;
3825 please see L<perlfunc/use> and L<perlfunc/import>. While an
3826 explicit import list would probably have caught this error earlier
3827 it naturally does not remedy the fact that your operating system
3828 still does not support that constant. Maybe you have a typo in
3829 the constants of the symbol import list of B<use> or B<import> or in the
3830 constant name at the line where this error was triggered?
3832 =item No command into which to pipe on command line
3834 (F) An error peculiar to VMS. Perl handles its own command line
3835 redirection, and found a '|' at the end of the command line, so it
3836 doesn't know where you want to pipe the output from this command.
3838 =item No DB::DB routine defined
3840 (F) The currently executing code was compiled with the B<-d> switch, but
3841 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3842 module) didn't define a routine to be called at the beginning of each
3845 =item No dbm on this machine
3847 (P) This is counted as an internal error, because every machine should
3848 supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
3850 =item No DB::sub routine defined
3852 (F) The currently executing code was compiled with the B<-d> switch, but
3853 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3854 module) didn't define a C<DB::sub> routine to be called at the beginning
3855 of each ordinary subroutine call.
3857 =item No directory specified for -I
3859 (F) The B<-I> command-line switch requires a directory name as part of the
3860 I<same> argument. Use B<-Ilib>, for instance. B<-I lib> won't work.
3862 =item No error file after 2> or 2>> on command line
3864 (F) An error peculiar to VMS. Perl handles its own command line
3865 redirection, and found a '2>' or a '2>>' on the command line, but can't
3866 find the name of the file to which to write data destined for stderr.
3868 =item No group ending character '%c' found in template
3870 (F) A pack or unpack template has an opening '(' or '[' without its
3871 matching counterpart. See L<perlfunc/pack>.
3873 =item No input file after < on command line
3875 (F) An error peculiar to VMS. Perl handles its own command line
3876 redirection, and found a '<' on the command line, but can't find the
3877 name of the file from which to read data for stdin.
3879 =item No next::method '%s' found for %s
3881 (F) C<next::method> found no further instances of this method name
3882 in the remaining packages of the MRO of this class. If you don't want
3883 it throwing an exception, use C<maybe::next::method>
3884 or C<next::can>. See L<mro>.
3886 =item Non-finite repeat count does nothing
3888 (W numeric) You tried to execute the
3889 L<C<x>|perlop/Multiplicative Operators> repetition operator C<Inf> (or
3890 C<-Inf>) or C<NaN> times, which doesn't make sense.
3892 =item Non-hex character in regex; marked by S<<-- HERE> in m/%s/
3894 (F) In a regular expression, there was a non-hexadecimal character where
3895 a hex one was expected, like
3900 =item Non-octal character in regex; marked by S<<-- HERE> in m/%s/
3902 (F) In a regular expression, there was a non-octal character where
3903 an octal one was expected, like
3907 =item Non-octal character '%c'. Resolved as "%s"
3909 (W digit) In parsing an octal numeric constant, a character was
3910 unexpectedly encountered that isn't octal. The resulting value
3913 =item "no" not allowed in expression
3915 (F) The "no" keyword is recognized and executed at compile time, and
3916 returns no useful value. See L<perlmod>.
3918 =item Non-string passed as bitmask
3920 (W misc) A number has been passed as a bitmask argument to select().
3921 Use the vec() function to construct the file descriptor bitmasks for
3922 select. See L<perlfunc/select>.
3924 =item No output file after > on command line
3926 (F) An error peculiar to VMS. Perl handles its own command line
3927 redirection, and found a lone '>' at the end of the command line, so it
3928 doesn't know where you wanted to redirect stdout.
3930 =item No output file after > or >> on command line
3932 (F) An error peculiar to VMS. Perl handles its own command line
3933 redirection, and found a '>' or a '>>' on the command line, but can't
3934 find the name of the file to which to write data destined for stdout.
3936 =item No package name allowed for variable %s in "our"
3938 (F) Fully qualified variable names are not allowed in "our"
3939 declarations, because that doesn't make much sense under existing
3940 rules. Such syntax is reserved for future extensions.
3942 =item No Perl script found in input
3944 (F) You called C<perl -x>, but no line was found in the file beginning
3945 with #! and containing the word "perl".
3947 =item No setregid available
3949 (F) Configure didn't find anything resembling the setregid() call for
3952 =item No setreuid available
3954 (F) Configure didn't find anything resembling the setreuid() call for
3957 =item No such class %s
3959 (F) You provided a class qualifier in a "my", "our" or "state"
3960 declaration, but this class doesn't exist at this point in your program.
3962 =item No such class field "%s" in variable %s of type %s
3964 (F) You tried to access a key from a hash through the indicated typed
3965 variable but that key is not allowed by the package of the same type.
3966 The indicated package has restricted the set of allowed keys using the
3969 =item No such hook: %s
3971 (F) You specified a signal hook that was not recognized by Perl.
3972 Currently, Perl accepts C<__DIE__> and C<__WARN__> as valid signal hooks.
3974 =item No such pipe open
3976 (P) An error peculiar to VMS. The internal routine my_pclose() tried to
3977 close a pipe which hadn't been opened. This should have been caught
3978 earlier as an attempt to close an unopened filehandle.
3980 =item No such signal: SIG%s
3982 (W signal) You specified a signal name as a subscript to %SIG that was
3983 not recognized. Say C<kill -l> in your shell to see the valid signal
3984 names on your system.
3986 =item Not a CODE reference
3988 (F) Perl was trying to evaluate a reference to a code value (that is, a
3989 subroutine), but found a reference to something else instead. You can
3990 use the ref() function to find out what kind of ref it really was. See
3993 =item Not a GLOB reference
3995 (F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
3996 symbol table entry that looks like C<*foo>), but found a reference to
3997 something else instead. You can use the ref() function to find out what
3998 kind of ref it really was. See L<perlref>.
4000 =item Not a HASH reference
4002 (F) Perl was trying to evaluate a reference to a hash value, but found a
4003 reference to something else instead. You can use the ref() function to
4004 find out what kind of ref it really was. See L<perlref>.
4006 =item Not an ARRAY reference
4008 (F) Perl was trying to evaluate a reference to an array value, but found
4009 a reference to something else instead. You can use the ref() function
4010 to find out what kind of ref it really was. See L<perlref>.
4012 =item Not a SCALAR reference
4014 (F) Perl was trying to evaluate a reference to a scalar value, but found
4015 a reference to something else instead. You can use the ref() function
4016 to find out what kind of ref it really was. See L<perlref>.
4018 =item Not a subroutine reference
4020 (F) Perl was trying to evaluate a reference to a code value (that is, a
4021 subroutine), but found a reference to something else instead. You can
4022 use the ref() function to find out what kind of ref it really was. See
4025 =item Not a subroutine reference in overload table
4027 (F) An attempt was made to specify an entry in an overloading table that
4028 doesn't somehow point to a valid subroutine. See L<overload>.
4030 =item Not enough arguments for %s
4032 (F) The function requires more arguments than you specified.
4034 =item Not enough format arguments
4036 (W syntax) A format specified more picture fields than the next line
4037 supplied. See L<perlform>.
4041 (A) You've accidentally run your script through the Bourne shell instead
4042 of Perl. Check the #! line, or manually feed your script into Perl
4045 =item (?[...]) not valid in locale in regex; marked by S<<-- HERE> in m/%s/
4047 (F) C<(?[...])> cannot be used within the scope of a C<S<use locale>> or with
4048 an C</l> regular expression modifier, as that would require deferring
4049 to run-time the calculation of what it should evaluate to, and it is
4050 regex compile-time only.
4052 =item no UTC offset information; assuming local time is UTC
4054 (S) A warning peculiar to VMS. Perl was unable to find the local
4055 timezone offset, so it's assuming that local system time is equivalent
4056 to UTC. If it's not, define the logical name
4057 F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
4058 need to be added to UTC to get local time.
4060 =item NULL OP IN RUN
4062 (S debugging) Some internal routine called run() with a null opcode
4065 =item Null picture in formline
4067 (F) The first argument to formline must be a valid format picture
4068 specification. It was found to be empty, which probably means you
4069 supplied it an uninitialized value. See L<perlform>.
4073 (P) An attempt was made to realloc NULL.
4075 =item NULL regexp argument
4077 (P) The internal pattern matching routines blew it big time.
4079 =item NULL regexp parameter
4081 (P) The internal pattern matching routines are out of their gourd.
4083 =item Number too long
4085 (F) Perl limits the representation of decimal numbers in programs to
4086 about 250 characters. You've exceeded that length. Future
4087 versions of Perl are likely to eliminate this arbitrary limitation. In
4088 the meantime, try using scientific notation (e.g. "1e6" instead of
4091 =item Number with no digits
4093 (F) Perl was looking for a number but found nothing that looked like
4094 a number. This happens, for example with C<\o{}>, with no number between
4097 =item Octal number > 037777777777 non-portable
4099 (W portable) The octal number you specified is larger than 2**32-1
4100 (4294967295) and therefore non-portable between systems. See
4101 L<perlport> for more on portability concerns.
4103 =item Odd name/value argument for subroutine
4105 (F) A subroutine using a slurpy hash parameter in its signature
4106 received an odd number of arguments to populate the hash. It requires
4107 the arguments to be paired, with the same number of keys as values.
4108 The caller of the subroutine is presumably at fault. Inconveniently,
4109 this error will be reported at the location of the subroutine, not that
4112 =item Odd number of arguments for overload::constant
4114 (W overload) The call to overload::constant contained an odd number of
4115 arguments. The arguments should come in pairs.
4117 =item Odd number of elements in anonymous hash
4119 (W misc) You specified an odd number of elements to initialize a hash,
4120 which is odd, because hashes come in key/value pairs.
4122 =item Odd number of elements in hash assignment
4124 (W misc) You specified an odd number of elements to initialize a hash,
4125 which is odd, because hashes come in key/value pairs.
4127 =item Offset outside string
4129 (F)(W layer) You tried to do a read/write/send/recv/seek operation
4130 with an offset pointing outside the buffer. This is difficult to
4131 imagine. The sole exceptions to this are that zero padding will
4132 take place when going past the end of the string when either
4133 C<sysread()>ing a file, or when seeking past the end of a scalar opened
4134 for I/O (in anticipation of future reads and to imitate the behavior
4137 =item Only one /x regex modifier is allowed
4139 =item Only one /x regex modifier is allowed in regex; marked by <-- HERE in m/%s/
4141 (F) You used the C</x> regular expression pattern modifier at least twice in a
4142 string of modifiers. This has been made illegal, in order to allow future
4143 extensions to the Perl language.
4145 =item %s() on unopened %s
4147 (W unopened) An I/O operation was attempted on a filehandle that was
4148 never initialized. You need to do an open(), a sysopen(), or a socket()
4149 call, or call a constructor from the FileHandle package.
4151 =item -%s on unopened filehandle %s
4153 (W unopened) You tried to invoke a file test operator on a filehandle
4154 that isn't open. Check your control flow. See also L<perlfunc/-X>.
4158 (S internal) An internal warning that the grammar is screwed up.
4162 (S internal) An internal warning that the grammar is screwed up.
4164 =item Opening dirhandle %s also as a file
4166 (D io, deprecated) You used open() to associate a filehandle to
4167 a symbol (glob or scalar) that already holds a dirhandle.
4168 Although legal, this idiom might render your code confusing
4171 =item Opening filehandle %s also as a directory
4173 (D io, deprecated) You used opendir() to associate a dirhandle to
4174 a symbol (glob or scalar) that already holds a filehandle.
4175 Although legal, this idiom might render your code confusing
4178 =item Operand with no preceding operator in regex; marked by S<<-- HERE> in
4181 (F) You wrote something like
4183 (?[ \p{Digit} \p{Thai} ])
4185 There are two operands, but no operator giving how you want to combine
4188 =item Operation "%s": no method found, %s
4190 (F) An attempt was made to perform an overloaded operation for which no
4191 handler was defined. While some handlers can be autogenerated in terms
4192 of other handlers, there is no default handler for any operation, unless
4193 the C<fallback> overloading key is specified to be true. See L<overload>.
4195 =item Operation "%s" returns its argument for non-Unicode code point 0x%X
4197 (S non_unicode) You performed an operation requiring Unicode rules
4198 on a code point that is not in Unicode, so what it should do is not
4199 defined. Perl has chosen to have it do nothing, and warn you.
4201 If the operation shown is "ToFold", it means that case-insensitive
4202 matching in a regular expression was done on the code point.
4204 If you know what you are doing you can turn off this warning by
4205 C<no warnings 'non_unicode';>.
4207 =item Operation "%s" returns its argument for UTF-16 surrogate U+%X
4209 (S surrogate) You performed an operation requiring Unicode
4210 rules on a Unicode surrogate. Unicode frowns upon the use
4211 of surrogates for anything but storing strings in UTF-16, but
4212 rules are (reluctantly) defined for the surrogates, and
4213 they are to do nothing for this operation. Because the use of
4214 surrogates can be dangerous, Perl warns.
4216 If the operation shown is "ToFold", it means that case-insensitive
4217 matching in a regular expression was done on the code point.
4219 If you know what you are doing you can turn off this warning by
4220 C<no warnings 'surrogate';>.
4222 =item Operator or semicolon missing before %s
4224 (S ambiguous) You used a variable or subroutine call where the parser
4225 was expecting an operator. The parser has assumed you really meant to
4226 use an operator, but this is highly likely to be incorrect. For
4227 example, if you say "*foo *foo" it will be interpreted as if you said
4230 =item Optional parameter lacks default expression
4232 (F) In a subroutine signature, you wrote something like "$a =", making a
4233 named optional parameter without a default value. A nameless optional
4234 parameter is permitted to have no default value, but a named one must
4235 have a specific default. You probably want "$a = undef".
4237 =item "our" variable %s redeclared
4239 (W misc) You seem to have already declared the same global once before
4240 in the current lexical scope.
4242 =item Out of memory!
4244 (X) The malloc() function returned 0, indicating there was insufficient
4245 remaining memory (or virtual memory) to satisfy the request. Perl has
4246 no option but to exit immediately.
4248 At least in Unix you may be able to get past this by increasing your
4249 process datasize limits: in csh/tcsh use C<limit> and
4250 C<limit datasize n> (where C<n> is the number of kilobytes) to check
4251 the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
4252 and C<ulimit -d n>, respectively.
4254 =item Out of memory during %s extend
4256 (X) An attempt was made to extend an array, a list, or a string beyond
4257 the largest possible memory allocation.
4259 =item Out of memory during "large" request for %s
4261 (F) The malloc() function returned 0, indicating there was insufficient
4262 remaining memory (or virtual memory) to satisfy the request. However,
4263 the request was judged large enough (compile-time default is 64K), so a
4264 possibility to shut down by trapping this error is granted.
4266 =item Out of memory during request for %s
4268 (X)(F) The malloc() function returned 0, indicating there was
4269 insufficient remaining memory (or virtual memory) to satisfy the
4272 The request was judged to be small, so the possibility to trap it
4273 depends on the way perl was compiled. By default it is not trappable.
4274 However, if compiled for this, Perl may use the contents of C<$^M> as an
4275 emergency pool after die()ing with this message. In this case the error
4276 is trappable I<once>, and the error message will include the line and file
4277 where the failed request happened.
4279 =item Out of memory during ridiculously large request
4281 (F) You can't allocate more than 2^31+"small amount" bytes. This error
4282 is most likely to be caused by a typo in the Perl program. e.g.,
4283 C<$arr[time]> instead of C<$arr[$time]>.
4285 =item Out of memory for yacc stack
4287 (F) The yacc parser wanted to grow its stack so it could continue
4288 parsing, but realloc() wouldn't give it more memory, virtual or
4291 =item '.' outside of string in pack
4293 (F) The argument to a '.' in your template tried to move the working
4294 position to before the start of the packed string being built.
4296 =item '@' outside of string in unpack
4298 (F) You had a template that specified an absolute position outside
4299 the string being unpacked. See L<perlfunc/pack>.
4301 =item '@' outside of string with malformed UTF-8 in unpack
4303 (F) You had a template that specified an absolute position outside
4304 the string being unpacked. The string being unpacked was also invalid
4305 UTF-8. See L<perlfunc/pack>.
4307 =item overload arg '%s' is invalid
4309 (W overload) The L<overload> pragma was passed an argument it did not
4310 recognize. Did you mistype an operator?
4312 =item Overloaded dereference did not return a reference
4314 (F) An object with an overloaded dereference operator was dereferenced,
4315 but the overloaded operation did not return a reference. See
4318 =item Overloaded qr did not return a REGEXP
4320 (F) An object with a C<qr> overload was used as part of a match, but the
4321 overloaded operation didn't return a compiled regexp. See L<overload>.
4323 =item %s package attribute may clash with future reserved word: %s
4325 (W reserved) A lowercase attribute name was used that had a
4326 package-specific handler. That name might have a meaning to Perl itself
4327 some day, even though it doesn't yet. Perhaps you should use a
4328 mixed-case attribute name, instead. See L<attributes>.
4330 =item pack/unpack repeat count overflow
4332 (F) You can't specify a repeat count so large that it overflows your
4333 signed integers. See L<perlfunc/pack>.
4337 (W io) A single call to write() produced more lines than can fit on a
4338 page. See L<perlform>.
4342 (P) An internal error.
4344 =item panic: attempt to call %s in %s
4346 (P) One of the file test operators entered a code branch that calls
4347 an ACL related-function, but that function is not available on this
4348 platform. Earlier checks mean that it should not be possible to
4349 enter this branch on this platform.
4351 =item panic: child pseudo-process was never scheduled
4353 (P) A child pseudo-process in the ithreads implementation on Windows
4354 was not scheduled within the time period allowed and therefore was not
4355 able to initialize properly.
4357 =item panic: ck_grep, type=%u
4359 (P) Failed an internal consistency check trying to compile a grep.
4361 =item panic: ck_split, type=%u
4363 (P) Failed an internal consistency check trying to compile a split.
4365 =item panic: corrupt saved stack index %ld
4367 (P) The savestack was requested to restore more localized values than
4368 there are in the savestack.
4370 =item panic: del_backref
4372 (P) Failed an internal consistency check while trying to reset a weak
4375 =item panic: do_subst
4377 (P) The internal pp_subst() routine was called with invalid operational
4380 =item panic: do_trans_%s
4382 (P) The internal do_trans routines were called with invalid operational
4385 =item panic: fold_constants JMPENV_PUSH returned %d
4387 (P) While attempting folding constants an exception other than an C<eval>
4390 =item panic: frexp: %f
4392 (P) The library function frexp() failed, making printf("%f") impossible.
4394 =item panic: goto, type=%u, ix=%ld
4396 (P) We popped the context stack to a context with the specified label,
4397 and then discovered it wasn't a context we know how to do a goto in.
4399 =item panic: gp_free failed to free glob pointer
4401 (P) The internal routine used to clear a typeglob's entries tried
4402 repeatedly, but each time something re-created entries in the glob.
4403 Most likely the glob contains an object with a reference back to
4404 the glob and a destructor that adds a new object to the glob.
4406 =item panic: INTERPCASEMOD, %s
4408 (P) The lexer got into a bad state at a case modifier.
4410 =item panic: INTERPCONCAT, %s
4412 (P) The lexer got into a bad state parsing a string with brackets.
4414 =item panic: kid popen errno read
4416 (F) A forked child returned an incomprehensible message about its errno.
4418 =item panic: last, type=%u
4420 (P) We popped the context stack to a block context, and then discovered
4421 it wasn't a block context.
4423 =item panic: leave_scope clearsv
4425 (P) A writable lexical variable became read-only somehow within the
4428 =item panic: leave_scope inconsistency %u
4430 (P) The savestack probably got out of sync. At least, there was an
4431 invalid enum on the top of it.
4433 =item panic: magic_killbackrefs
4435 (P) Failed an internal consistency check while trying to reset all weak
4436 references to an object.
4438 =item panic: malloc, %s
4440 (P) Something requested a negative number of bytes of malloc.
4442 =item panic: memory wrap
4444 (P) Something tried to allocate either more memory than possible or a
4447 =item panic: pad_alloc, %p!=%p
4449 (P) The compiler got confused about which scratch pad it was allocating
4450 and freeing temporaries and lexicals from.
4452 =item panic: pad_free curpad, %p!=%p
4454 (P) The compiler got confused about which scratch pad it was allocating
4455 and freeing temporaries and lexicals from.
4457 =item panic: pad_free po
4459 (P) A zero scratch pad offset was detected internally. An attempt was
4460 made to free a target that had not been allocated to begin with.
4462 =item panic: pad_reset curpad, %p!=%p
4464 (P) The compiler got confused about which scratch pad it was allocating
4465 and freeing temporaries and lexicals from.
4467 =item panic: pad_sv po
4469 (P) A zero scratch pad offset was detected internally. Most likely
4470 an operator needed a target but that target had not been allocated
4471 for whatever reason.
4473 =item panic: pad_swipe curpad, %p!=%p
4475 (P) The compiler got confused about which scratch pad it was allocating
4476 and freeing temporaries and lexicals from.
4478 =item panic: pad_swipe po
4480 (P) An invalid scratch pad offset was detected internally.
4482 =item panic: pp_iter, type=%u
4484 (P) The foreach iterator got called in a non-loop context frame.
4486 =item panic: pp_match%s
4488 (P) The internal pp_match() routine was called with invalid operational
4491 =item panic: pp_split, pm=%p, s=%p
4493 (P) Something terrible went wrong in setting up for the split.
4495 =item panic: realloc, %s
4497 (P) Something requested a negative number of bytes of realloc.
4499 =item panic: reference miscount on nsv in sv_replace() (%d != 1)
4501 (P) The internal sv_replace() function was handed a new SV with a
4502 reference count other than 1.
4504 =item panic: restartop in %s
4506 (P) Some internal routine requested a goto (or something like it), and
4507 didn't supply the destination.
4509 =item panic: return, type=%u
4511 (P) We popped the context stack to a subroutine or eval context, and
4512 then discovered it wasn't a subroutine or eval context.
4514 =item panic: scan_num, %s
4516 (P) scan_num() got called on something that wasn't a number.
4518 =item panic: Sequence (?{...}): no code block found in regex m/%s/
4520 (P) While compiling a pattern that has embedded (?{}) or (??{}) code
4521 blocks, perl couldn't locate the code block that should have already been
4522 seen and compiled by perl before control passed to the regex compiler.
4524 =item panic: strxfrm() gets absurd - a => %u, ab => %u
4526 (P) The interpreter's sanity check of the C function strxfrm() failed.
4527 In your current locale the returned transformation of the string "ab"
4528 is shorter than that of the string "a", which makes no sense.
4530 =item panic: sv_chop %s
4532 (P) The sv_chop() routine was passed a position that is not within the
4533 scalar's string buffer.
4535 =item panic: sv_insert, midend=%p, bigend=%p
4537 (P) The sv_insert() routine was told to remove more string than there
4540 =item panic: top_env
4542 (P) The compiler attempted to do a goto, or something weird like that.
4544 =item panic: unimplemented op %s (#%d) called
4546 (P) The compiler is screwed up and attempted to use an op that isn't
4547 permitted at run time.
4549 =item panic: unknown OA_*: %x
4551 (P) The internal routine that handles arguments to C<&CORE::foo()>
4552 subroutine calls was unable to determine what type of arguments
4555 =item panic: utf16_to_utf8: odd bytelen
4557 (P) Something tried to call utf16_to_utf8 with an odd (as opposed
4558 to even) byte length.
4560 =item panic: utf16_to_utf8_reversed: odd bytelen
4562 (P) Something tried to call utf16_to_utf8_reversed with an odd (as opposed
4563 to even) byte length.
4565 =item panic: yylex, %s
4567 (P) The lexer got into a bad state while processing a case modifier.
4569 =item Parentheses missing around "%s" list
4571 (W parenthesis) You said something like
4577 my ($foo, $bar) = @_;
4579 Remember that "my", "our", "local" and "state" bind tighter than comma.
4581 =item Parsing code internal error (%s)
4583 (F) Parsing code supplied by an extension violated the parser's API in
4586 =item Passing malformed UTF-8 to "%s" is deprecated
4588 (D deprecated, utf8) This message indicates a bug either in the Perl
4589 core or in XS code. Such code was trying to find out if a character,
4590 allegedly stored internally encoded as UTF-8, was of a given type, such
4591 as being punctuation or a digit. But the character was not encoded in
4592 legal UTF-8. The C<%s> is replaced by a string that can be used by
4593 knowledgeable people to determine what the type being checked against
4594 was. If C<utf8> warnings are enabled, a further message is raised,
4595 giving details of the malformation.
4597 =item Pattern subroutine nesting without pos change exceeded limit in regex
4599 (F) You used a pattern that uses too many nested subpattern calls without
4600 consuming any text. Restructure the pattern so text is consumed before
4601 the nesting limit is exceeded.
4603 =item C<-p> destination: %s
4605 (F) An error occurred during the implicit output invoked by the C<-p>
4606 command-line switch. (This output goes to STDOUT unless you've
4607 redirected it with select().)
4609 =item Perl API version %s of %s does not match %s
4611 (F) The XS module in question was compiled against a different incompatible
4612 version of Perl than the one that has loaded the XS module.
4614 =item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
4615 utility to report; in regex; marked by S<<-- HERE> in m/%s/
4617 (S regexp) You used a regular expression with case-insensitive matching,
4618 and there is a bug in Perl in which the built-in regular expression
4619 folding rules are not accurate. This may lead to incorrect results.
4620 Please report this as a bug using the L<perlbug> utility.
4622 =item PerlIO layer ':win32' is experimental
4624 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
4625 experimental. If you want to take the risk of using this layer,
4626 simply disable this warning:
4628 no warnings "experimental::win32_perlio";
4630 =item Perl_my_%s() not available
4632 (F) Your platform has very uncommon byte-order and integer size,
4633 so it was not possible to set up some or all fixed-width byte-order
4634 conversion functions. This is only a problem when you're using the
4635 '<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
4637 =item Perl %s required (did you mean %s?)--this is only %s, stopped
4639 (F) The code you are trying to run has asked for a newer version of
4640 Perl than you are running. Perhaps C<use 5.10> was written instead
4641 of C<use 5.010> or C<use v5.10>. Without the leading C<v>, the number is
4642 interpreted as a decimal, with every three digits after the
4643 decimal point representing a part of the version number. So 5.10
4644 is equivalent to v5.100.
4646 =item Perl %s required--this is only %s, stopped
4648 (F) The module in question uses features of a version of Perl more
4649 recent than the currently running version. How long has it been since
4650 you upgraded, anyway? See L<perlfunc/require>.
4652 =item PERL_SH_DIR too long
4654 (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
4655 C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
4657 =item PERL_SIGNALS illegal: "%s"
4659 (X) See L<perlrun/PERL_SIGNALS> for legal values.
4661 =item Perls since %s too modern--this is %s, stopped
4663 (F) The code you are trying to run claims it will not run
4664 on the version of Perl you are using because it is too new.
4665 Maybe the code needs to be updated, or maybe it is simply
4666 wrong and the version check should just be removed.
4668 =item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only partially set
4670 (S) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
4671 contained a non hex character. This could mean you are not using the
4672 hash seed you think you are.
4674 =item perl: warning: Setting locale failed.
4676 (S) The whole warning message will look something like:
4678 perl: warning: Setting locale failed.
4679 perl: warning: Please check that your locale settings:
4682 are supported and installed on your system.
4683 perl: warning: Falling back to the standard locale ("C").
4685 Exactly what were the failed locale settings varies. In the above the
4686 settings were that the LC_ALL was "En_US" and the LANG had no value.
4687 This error means that Perl detected that you and/or your operating
4688 system supplier and/or system administrator have set up the so-called
4689 locale system but Perl could not use those settings. This was not
4690 dead serious, fortunately: there is a "default locale" called "C" that
4691 Perl can and will use, and the script will be run. Before you really
4692 fix the problem, however, you will get the same error message each
4693 time you run Perl. How to really fix the problem can be found in
4694 L<perllocale> section B<LOCALE PROBLEMS>.
4696 =item perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
4698 (S) Perl was run with the environment variable PERL_PERTURB_KEYS defined
4699 but containing an unexpected value. The legal values of this setting
4702 Numeric | String | Result
4703 --------+---------------+-----------------------------------------
4704 0 | NO | Disables key traversal randomization
4705 1 | RANDOM | Enables full key traversal randomization
4706 2 | DETERMINISTIC | Enables repeatable key traversal
4709 Both numeric and string values are accepted, but note that string values are
4710 case sensitive. The default for this setting is "RANDOM" or 1.
4712 =item pid %x not a child
4714 (W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
4715 process which isn't a subprocess of the current process. While this is
4716 fine from VMS' perspective, it's probably not what you intended.
4718 =item 'P' must have an explicit size in unpack
4720 (F) The unpack format P must have an explicit size, not "*".
4722 =item POSIX class [:%s:] unknown in regex; marked by S<<-- HERE> in m/%s/
4724 (F) The class in the character class [: :] syntax is unknown. The S<<-- HERE>
4725 shows whereabouts in the regular expression the problem was discovered.
4726 Note that the POSIX character classes do B<not> have the C<is> prefix
4727 the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
4728 not C<isprint>. See L<perlre>.
4730 =item POSIX getpgrp can't take an argument
4732 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
4733 the BSD version, which takes a pid.
4735 =item POSIX syntax [%c %c] belongs inside character classes%s in regex; marked by
4736 S<<-- HERE> in m/%s/
4738 (W regexp) Perl thinks that you intended to write a POSIX character
4739 class, but didn't use enough brackets. These POSIX class constructs [:
4740 :], [= =], and [. .] go I<inside> character classes, the [] are part of
4741 the construct, for example: C<qr/[012[:alpha:]345]/>. What the regular
4742 expression pattern compiled to is probably not what you were intending.
4743 For example, C<qr/[:alpha:]/> compiles to a regular bracketed character
4744 class consisting of the four characters C<":">, C<"a">, C<"l">,
4745 C<"h">, and C<"p">. To specify the POSIX class, it should have been
4746 written C<qr/[[:alpha:]]/>.
4748 Note that [= =] and [. .] are not currently
4749 implemented; they are simply placeholders for future extensions and
4750 will cause fatal errors. The S<<-- HERE> shows whereabouts in the regular
4751 expression the problem was discovered. See L<perlre>.
4753 If the specification of the class was not completely valid, the message
4756 =item POSIX syntax [. .] is reserved for future extensions in regex; marked by
4757 S<<-- HERE> in m/%s/
4759 (F) Within regular expression character classes ([]) the syntax beginning
4760 with "[." and ending with ".]" is reserved for future extensions. If you
4761 need to represent those character sequences inside a regular expression
4762 character class, just quote the square brackets with the backslash: "\[."
4763 and ".\]". The S<<-- HERE> shows whereabouts in the regular expression the
4764 problem was discovered. See L<perlre>.
4766 =item POSIX syntax [= =] is reserved for future extensions in regex; marked by
4767 S<<-- HERE> in m/%s/
4769 (F) Within regular expression character classes ([]) the syntax beginning
4770 with "[=" and ending with "=]" is reserved for future extensions. If you
4771 need to represent those character sequences inside a regular expression
4772 character class, just quote the square brackets with the backslash: "\[="
4773 and "=\]". The S<<-- HERE> shows whereabouts in the regular expression the
4774 problem was discovered. See L<perlre>.
4776 =item Possible attempt to put comments in qw() list
4778 (W qw) qw() lists contain items separated by whitespace; as with literal
4779 strings, comment characters are not ignored, but are instead treated as
4780 literal data. (You may have used different delimiters than the
4781 parentheses shown here; braces are also frequently used.)
4783 You probably wrote something like this:
4790 when you should have written this:
4797 If you really want comments, build your list the
4798 old-fashioned way, with quotes and commas:
4802 'b', # another comment
4805 =item Possible attempt to separate words with commas
4807 (W qw) qw() lists contain items separated by whitespace; therefore
4808 commas aren't needed to separate the items. (You may have used
4809 different delimiters than the parentheses shown here; braces are also
4812 You probably wrote something like this:
4816 which puts literal commas into some of the list items. Write it without
4817 commas if you don't want them to appear in your data:
4821 =item Possible memory corruption: %s overflowed 3rd argument
4823 (F) An ioctl() or fcntl() returned more than Perl was bargaining for.
4824 Perl guesses a reasonable buffer size, but puts a sentinel byte at the
4825 end of the buffer just in case. This sentinel byte got clobbered, and
4826 Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
4828 =item Possible precedence issue with control flow operator
4830 (W syntax) There is a possible problem with the mixing of a control
4831 flow operator (e.g. C<return>) and a low-precedence operator like
4834 sub { return $a or $b; }
4838 sub { (return $a) or $b; }
4840 Which is effectively just:
4844 Either use parentheses or the high-precedence variant of the operator.
4846 Note this may be also triggered for constructs like:
4850 =item Possible precedence problem on bitwise %s operator
4852 (W precedence) Your program uses a bitwise logical operator in conjunction
4853 with a numeric comparison operator, like this :
4855 if ($x & $y == 0) { ... }
4857 This expression is actually equivalent to C<$x & ($y == 0)>, due to the
4858 higher precedence of C<==>. This is probably not what you want. (If you
4859 really meant to write this, disable the warning, or, better, put the
4860 parentheses explicitly and write C<$x & ($y == 0)>).
4862 =item Possible unintended interpolation of $\ in regex
4864 (W ambiguous) You said something like C<m/$\/> in a regex.
4865 The regex C<m/foo$\s+bar/m> translates to: match the word 'foo', the output
4866 record separator (see L<perlvar/$\>) and the letter 's' (one time or more)
4867 followed by the word 'bar'.
4869 If this is what you intended then you can silence the warning by using
4870 C<m/${\}/> (for example: C<m/foo${\}s+bar/>).
4872 If instead you intended to match the word 'foo' at the end of the line
4873 followed by whitespace and the word 'bar' on the next line then you can use
4874 C<m/$(?)\/> (for example: C<m/foo$(?)\s+bar/>).
4876 =item Possible unintended interpolation of %s in string
4878 (W ambiguous) You said something like '@foo' in a double-quoted string
4879 but there was no array C<@foo> in scope at the time. If you wanted a
4880 literal @foo, then write it as \@foo; otherwise find out what happened
4881 to the array you apparently lost track of.
4883 =item Precedence problem: open %s should be open(%s)
4885 (S precedence) The old irregular construct
4889 is now misinterpreted as
4893 because of the strict regularization of Perl 5's grammar into unary and
4894 list operators. (The old open was a little of both.) You must put
4895 parentheses around the filehandle, or use the new "or" operator instead
4898 =item Premature end of script headers
4902 =item printf() on closed filehandle %s
4904 (W closed) The filehandle you're writing to got itself closed sometime
4905 before now. Check your control flow.
4907 =item print() on closed filehandle %s
4909 (W closed) The filehandle you're printing on got itself closed sometime
4910 before now. Check your control flow.
4912 =item Process terminated by SIG%s
4914 (W) This is a standard message issued by OS/2 applications, while *nix
4915 applications die in silence. It is considered a feature of the OS/2
4916 port. One can easily disable this by appropriate sighandlers, see
4917 L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
4920 =item Prototype after '%c' for %s : %s
4922 (W illegalproto) A character follows % or @ in a prototype. This is
4923 useless, since % and @ gobble the rest of the subroutine arguments.
4925 =item Prototype mismatch: %s vs %s
4927 (S prototype) The subroutine being declared or defined had previously been
4928 declared or defined with a different function prototype.
4930 =item Prototype not terminated
4932 (F) You've omitted the closing parenthesis in a function prototype
4935 =item Prototype '%s' overridden by attribute 'prototype(%s)' in %s
4937 (W prototype) A prototype was declared in both the parentheses after
4938 the sub name and via the prototype attribute. The prototype in
4939 parentheses is useless, since it will be replaced by the prototype
4940 from the attribute before it's ever used.
4942 =item Quantifier follows nothing in regex; marked by S<<-- HERE> in m/%s/
4944 (F) You started a regular expression with a quantifier. Backslash it if
4945 you meant it literally. The S<<-- HERE> shows whereabouts in the regular
4946 expression the problem was discovered. See L<perlre>.
4948 =item Quantifier in {,} bigger than %d in regex; marked by S<<-- HERE> in m/%s/
4950 (F) There is currently a limit to the size of the min and max values of
4951 the {min,max} construct. The S<<-- HERE> shows whereabouts in the regular
4952 expression the problem was discovered. See L<perlre>.
4954 =item Quantifier {n,m} with n > m can't match in regex
4956 =item Quantifier {n,m} with n > m can't match in regex; marked by
4957 S<<-- HERE> in m/%s/
4959 (W regexp) Minima should be less than or equal to maxima. If you really
4960 want your regexp to match something 0 times, just put {0}.
4962 =item Quantifier unexpected on zero-length expression in regex m/%s/
4964 (W regexp) You applied a regular expression quantifier in a place where
4965 it makes no sense, such as on a zero-width assertion. Try putting the
4966 quantifier inside the assertion instead. For example, the way to match
4967 "abc" provided that it is followed by three repetitions of "xyz" is
4968 C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
4970 =item Range iterator outside integer range
4972 (F) One (or both) of the numeric arguments to the range operator ".."
4973 are outside the range which can be represented by integers internally.
4974 One possible workaround is to force Perl to use magical string increment
4975 by prepending "0" to your numbers.
4977 =item Ranges of ASCII printables should be some subset of "0-9", "A-Z", or
4978 "a-z" in regex; marked by S<<-- HERE> in m/%s/
4980 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
4982 Stricter rules help to find typos and other errors. Perhaps you didn't
4983 even intend a range here, if the C<"-"> was meant to be some other
4984 character, or should have been escaped (like C<"\-">). If you did
4985 intend a range, the one that was used is not portable between ASCII and
4986 EBCDIC platforms, and doesn't have an obvious meaning to a casual
4989 [3-7] # OK; Obvious and portable
4990 [d-g] # OK; Obvious and portable
4991 [A-Y] # OK; Obvious and portable
4992 [A-z] # WRONG; Not portable; not clear what is meant
4993 [a-Z] # WRONG; Not portable; not clear what is meant
4994 [%-.] # WRONG; Not portable; not clear what is meant
4995 [\x41-Z] # WRONG; Not portable; not obvious to non-geek
4997 (You can force portability by specifying a Unicode range, which means that
4998 the endpoints are specified by
4999 L<C<\N{...}>|perlrecharclass/Character Ranges>, but the meaning may
5000 still not be obvious.)
5001 The stricter rules require that ranges that start or stop with an ASCII
5002 character that is not a control have all their endpoints be the literal
5003 character, and not some escape sequence (like C<"\x41">), and the ranges
5004 must be all digits, or all uppercase letters, or all lowercase letters.
5006 =item Ranges of digits should be from the same group in regex; marked by
5007 S<<-- HERE> in m/%s/
5009 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
5011 Stricter rules help to find typos and other errors. You included a
5012 range, and at least one of the end points is a decimal digit. Under the
5013 stricter rules, when this happens, both end points should be digits in
5014 the same group of 10 consecutive digits.
5016 =item readdir() attempted on invalid dirhandle %s
5018 (W io) The dirhandle you're reading from is either closed or not really
5019 a dirhandle. Check your control flow.
5021 =item readline() on closed filehandle %s
5023 (W closed) The filehandle you're reading from got itself closed sometime
5024 before now. Check your control flow.
5026 =item read() on closed filehandle %s
5028 (W closed) You tried to read from a closed filehandle.
5030 =item read() on unopened filehandle %s
5032 (W unopened) You tried to read from a filehandle that was never opened.
5034 =item Reallocation too large: %x
5036 (F) You can't allocate more than 64K on an MS-DOS machine.
5038 =item realloc() of freed memory ignored
5040 (S malloc) An internal routine called realloc() on something that had
5043 =item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
5045 (S debugging) You can't use the B<-D> option unless the code to produce
5046 the desired output is compiled into Perl, which entails some overhead,
5047 which is why it's currently left out of your copy.
5049 =item Recursive call to Perl_load_module in PerlIO_find_layer
5051 (P) It is currently not permitted to load modules when creating
5052 a filehandle inside an %INC hook. This can happen with C<open my
5053 $fh, '<', \$scalar>, which implicitly loads PerlIO::scalar. Try
5054 loading PerlIO::scalar explicitly first.
5056 =item Recursive inheritance detected in package '%s'
5058 (F) While calculating the method resolution order (MRO) of a package, Perl
5059 believes it found an infinite loop in the C<@ISA> hierarchy. This is a
5060 crude check that bails out after 100 levels of C<@ISA> depth.
5062 =item Redundant argument in %s
5064 (W redundant) You called a function with more arguments than other
5065 arguments you supplied indicated would be needed. Currently only
5066 emitted when a printf-type format required fewer arguments than were
5067 supplied, but might be used in the future for e.g. L<perlfunc/pack>.
5069 =item refcnt_dec: fd %d%s
5071 =item refcnt: fd %d%s
5073 =item refcnt_inc: fd %d%s
5075 (P) Perl's I/O implementation failed an internal consistency check. If
5076 you see this message, something is very wrong.
5078 =item Reference found where even-sized list expected
5080 (W misc) You gave a single reference where Perl was expecting a list
5081 with an even number of elements (for assignment to a hash). This
5082 usually means that you used the anon hash constructor when you meant
5083 to use parens. In any case, a hash requires key/value B<pairs>.
5085 %hash = { one => 1, two => 2, }; # WRONG
5086 %hash = [ qw/ an anon array / ]; # WRONG
5087 %hash = ( one => 1, two => 2, ); # right
5088 %hash = qw( one 1 two 2 ); # also fine
5090 =item Reference is already weak
5092 (W misc) You have attempted to weaken a reference that is already weak.
5093 Doing so has no effect.
5095 =item Reference to invalid group 0 in regex; marked by S<<-- HERE> in m/%s/
5097 (F) You used C<\g0> or similar in a regular expression. You may refer
5098 to capturing parentheses only with strictly positive integers
5099 (normal backreferences) or with strictly negative integers (relative
5100 backreferences). Using 0 does not make sense.
5102 =item Reference to nonexistent group in regex; marked by S<<-- HERE> in
5105 (F) You used something like C<\7> in your regular expression, but there are
5106 not at least seven sets of capturing parentheses in the expression. If
5107 you wanted to have the character with ordinal 7 inserted into the regular
5108 expression, prepend zeroes to make it three digits long: C<\007>
5110 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5113 =item Reference to nonexistent named group in regex; marked by S<<-- HERE>
5116 (F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
5117 expression, but there is no corresponding named capturing parentheses
5118 such as C<(?'NAME'...)> or C<< (?<NAME>...) >>. Check if the name has been
5119 spelled correctly both in the backreference and the declaration.
5121 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5124 =item Reference to nonexistent or unclosed group in regex; marked by
5125 S<<-- HERE> in m/%s/
5127 (F) You used something like C<\g{-7}> in your regular expression, but there
5128 are not at least seven sets of closed capturing parentheses in the
5129 expression before where the C<\g{-7}> was located.
5131 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5134 =item regexp memory corruption
5136 (P) The regular expression engine got confused by what the regular
5137 expression compiler gave it.
5139 =item Regexp modifier "/%c" may appear a maximum of twice
5141 =item Regexp modifier "%c" may appear a maximum of twice in regex; marked
5142 by S<<-- HERE> in m/%s/
5144 (F) The regular expression pattern had too many occurrences
5145 of the specified modifier. Remove the extraneous ones.
5147 =item Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
5150 (F) Turning off the given modifier has the side effect of turning on
5151 another one. Perl currently doesn't allow this. Reword the regular
5152 expression to use the modifier you want to turn on (and place it before
5153 the minus), instead of the one you want to turn off.
5155 =item Regexp modifier "/%c" may not appear twice
5157 =item Regexp modifier "%c" may not appear twice in regex; marked by <--
5160 (F) The regular expression pattern had too many occurrences
5161 of the specified modifier. Remove the extraneous ones.
5163 =item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5165 =item Regexp modifiers "%c" and "%c" are mutually exclusive in regex;
5166 marked by S<<-- HERE> in m/%s/
5168 (F) The regular expression pattern had more than one of these
5169 mutually exclusive modifiers. Retain only the modifier that is
5170 supposed to be there.
5172 =item Regexp out of space in regex m/%s/
5174 (P) A "can't happen" error, because safemalloc() should have caught it
5177 =item Repeated format line will never terminate (~~ and @#)
5179 (F) Your format contains the ~~ repeat-until-blank sequence and a
5180 numeric field that will never go blank so that the repetition never
5181 terminates. You might use ^# instead. See L<perlform>.
5183 =item Replacement list is longer than search list
5185 (W misc) You have used a replacement list that is longer than the
5186 search list. So the additional elements in the replacement list
5189 =item '%s' resolved to '\o{%s}%d'
5191 (W misc, regexp) You wrote something like C<\08>, or C<\179> in a
5192 double-quotish string. All but the last digit is treated as a single
5193 character, specified in octal. The last digit is the next character in
5194 the string. To tell Perl that this is indeed what you want, you can use
5195 the C<\o{ }> syntax, or use exactly three digits to specify the octal
5198 =item Reversed %s= operator
5200 (W syntax) You wrote your assignment operator backwards. The = must
5201 always come last, to avoid ambiguity with subsequent unary operators.
5203 =item rewinddir() attempted on invalid dirhandle %s
5205 (W io) The dirhandle you tried to do a rewinddir() on is either closed
5206 or not really a dirhandle. Check your control flow.
5208 =item Scalars leaked: %d
5210 (S internal) Something went wrong in Perl's internal bookkeeping
5211 of scalars: not all scalar variables were deallocated by the time
5212 Perl exited. What this usually indicates is a memory leak, which
5213 is of course bad, especially if the Perl program is intended to be
5216 =item Scalar value @%s[%s] better written as $%s[%s]
5218 (W syntax) You've used an array slice (indicated by @) to select a
5219 single element of an array. Generally it's better to ask for a scalar
5220 value (indicated by $). The difference is that C<$foo[&bar]> always
5221 behaves like a scalar, both when assigning to it and when evaluating its
5222 argument, while C<@foo[&bar]> behaves like a list when you assign to it,
5223 and provides a list context to its subscript, which can do weird things
5224 if you're expecting only one subscript.
5226 On the other hand, if you were actually hoping to treat the array
5227 element as a list, you need to look into how references work, because
5228 Perl will not magically convert between scalars and lists for you. See
5231 =item Scalar value @%s{%s} better written as $%s{%s}
5233 (W syntax) You've used a hash slice (indicated by @) to select a single
5234 element of a hash. Generally it's better to ask for a scalar value
5235 (indicated by $). The difference is that C<$foo{&bar}> always behaves
5236 like a scalar, both when assigning to it and when evaluating its
5237 argument, while C<@foo{&bar}> behaves like a list when you assign to it,
5238 and provides a list context to its subscript, which can do weird things
5239 if you're expecting only one subscript.
5241 On the other hand, if you were actually hoping to treat the hash element
5242 as a list, you need to look into how references work, because Perl will
5243 not magically convert between scalars and lists for you. See
5246 =item Search pattern not terminated
5248 (F) The lexer couldn't find the final delimiter of a // or m{}
5249 construct. Remember that bracketing delimiters count nesting level.
5250 Missing the leading C<$> from a variable C<$m> may cause this error.
5252 Note that since Perl 5.10.0 a // can also be the I<defined-or>
5253 construct, not just the empty search pattern. Therefore code written
5254 in Perl 5.10.0 or later that uses the // as the I<defined-or> can be
5255 misparsed by pre-5.10.0 Perls as a non-terminated search pattern.
5257 =item seekdir() attempted on invalid dirhandle %s
5259 (W io) The dirhandle you are doing a seekdir() on is either closed or not
5260 really a dirhandle. Check your control flow.
5262 =item %sseek() on unopened filehandle
5264 (W unopened) You tried to use the seek() or sysseek() function on a
5265 filehandle that was either never opened or has since been closed.
5267 =item select not implemented
5269 (F) This machine doesn't implement the select() system call.
5271 =item Self-ties of arrays and hashes are not supported
5273 (F) Self-ties are of arrays and hashes are not supported in
5274 the current implementation.
5276 =item Semicolon seems to be missing
5278 (W semicolon) A nearby syntax error was probably caused by a missing
5279 semicolon, or possibly some other missing operator, such as a comma.
5281 =item semi-panic: attempt to dup freed string
5283 (S internal) The internal newSVsv() routine was called to duplicate a
5284 scalar that had previously been marked as free.
5286 =item sem%s not implemented
5288 (F) You don't have System V semaphore IPC on your system.
5290 =item send() on closed socket %s
5292 (W closed) The socket you're sending to got itself closed sometime
5293 before now. Check your control flow.
5295 =item Sequence "\c{" invalid
5297 (F) These three characters may not appear in sequence in a
5298 double-quotish context. This message is raised only on non-ASCII
5299 platforms (a different error message is output on ASCII ones). If you
5300 were intending to specify a control character with this sequence, you'll
5301 have to use a different way to specify it.
5303 =item Sequence (? incomplete in regex; marked by S<<-- HERE> in m/%s/
5305 (F) A regular expression ended with an incomplete extension (?. The
5306 S<<-- HERE> shows whereabouts in the regular expression the problem was
5307 discovered. See L<perlre>.
5309 =item Sequence (?%c...) not implemented in regex; marked by S<<-- HERE> in
5312 (F) A proposed regular expression extension has the character reserved
5313 but has not yet been written. The S<<-- HERE> shows whereabouts in the
5314 regular expression the problem was discovered. See L<perlre>.
5316 =item Sequence (?%s...) not recognized in regex; marked by S<<-- HERE> in
5319 (F) You used a regular expression extension that doesn't make sense.
5320 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5321 discovered. This may happen when using the C<(?^...)> construct to tell
5322 Perl to use the default regular expression modifiers, and you
5323 redundantly specify a default modifier. For other
5324 causes, see L<perlre>.
5326 =item Sequence (?#... not terminated in regex m/%s/
5328 (F) A regular expression comment must be terminated by a closing
5329 parenthesis. Embedded parentheses aren't allowed. See
5332 =item Sequence (?&... not terminated in regex; marked by S<<-- HERE> in
5335 (F) A named reference of the form C<(?&...)> was missing the final
5336 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5337 in the regular expression the problem was discovered.
5339 =item Sequence (?%c... not terminated in regex; marked by S<<-- HERE>
5342 (F) A named group of the form C<(?'...')> or C<< (?<...>) >> was missing the final
5343 closing quote or angle bracket. The S<<-- HERE> shows whereabouts in the
5344 regular expression the problem was discovered.
5346 =item Sequence (?(%c... not terminated in regex; marked by S<<-- HERE>
5349 (F) A named reference of the form C<(?('...')...)> or C<< (?(<...>)...) >> was
5350 missing the final closing quote or angle bracket after the name. The
5351 S<<-- HERE> shows whereabouts in the regular expression the problem was
5354 =item Sequence (?... not terminated in regex; marked by S<<-- HERE> in
5357 (F) There was no matching closing parenthesis for the '('. The
5358 S<<-- HERE> shows whereabouts in the regular expression the problem was
5361 =item Sequence \%s... not terminated in regex; marked by S<<-- HERE> in
5364 (F) The regular expression expects a mandatory argument following the escape
5365 sequence and this has been omitted or incorrectly written.
5367 =item Sequence (?{...}) not terminated with ')'
5369 (F) The end of the perl code contained within the {...} must be
5370 followed immediately by a ')'.
5372 =item Sequence (?PE<gt>... not terminated in regex; marked by S<<-- HERE> in m/%s/
5374 (F) A named reference of the form C<(?PE<gt>...)> was missing the final
5375 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5376 in the regular expression the problem was discovered.
5378 =item Sequence (?PE<lt>... not terminated in regex; marked by S<<-- HERE> in m/%s/
5380 (F) A named group of the form C<(?PE<lt>...E<gt>')> was missing the final
5381 closing angle bracket. The S<<-- HERE> shows whereabouts in the
5382 regular expression the problem was discovered.
5384 =item Sequence ?P=... not terminated in regex; marked by S<<-- HERE> in
5387 (F) A named reference of the form C<(?P=...)> was missing the final
5388 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5389 in the regular expression the problem was discovered.
5391 =item Sequence (?R) not terminated in regex m/%s/
5393 (F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
5396 =item Server error (a.k.a. "500 Server error")
5398 (A) This is the error message generally seen in a browser window
5399 when trying to run a CGI program (including SSI) over the web. The
5400 actual error text varies widely from server to server. The most
5401 frequently-seen variants are "500 Server error", "Method (something)
5402 not permitted", "Document contains no data", "Premature end of script
5403 headers", and "Did not produce a valid header".
5405 B<This is a CGI error, not a Perl error>.
5407 You need to make sure your script is executable, is accessible by
5408 the user CGI is running the script under (which is probably not the
5409 user account you tested it under), does not rely on any environment
5410 variables (like PATH) from the user it isn't running under, and isn't
5411 in a location where the CGI server can't find it, basically, more or
5412 less. Please see the following for more information:
5414 http://www.perl.org/CGI_MetaFAQ.html
5415 http://www.htmlhelp.org/faq/cgifaq.html
5416 http://www.w3.org/Security/Faq/
5418 You should also look at L<perlfaq9>.
5420 =item setegid() not implemented
5422 (F) You tried to assign to C<$)>, and your operating system doesn't
5423 support the setegid() system call (or equivalent), or at least Configure
5426 =item seteuid() not implemented
5428 (F) You tried to assign to C<< $> >>, and your operating system doesn't
5429 support the seteuid() system call (or equivalent), or at least Configure
5432 =item setpgrp can't take arguments
5434 (F) Your system has the setpgrp() from BSD 4.2, which takes no
5435 arguments, unlike POSIX setpgid(), which takes a process ID and process
5438 =item setrgid() not implemented
5440 (F) You tried to assign to C<$(>, and your operating system doesn't
5441 support the setrgid() system call (or equivalent), or at least Configure
5444 =item setruid() not implemented
5446 (F) You tried to assign to C<$<>, and your operating system doesn't
5447 support the setruid() system call (or equivalent), or at least Configure
5450 =item setsockopt() on closed socket %s
5452 (W closed) You tried to set a socket option on a closed socket. Did you
5453 forget to check the return value of your socket() call? See
5454 L<perlfunc/setsockopt>.
5456 =item Setting ${^ENCODING} is deprecated
5458 (D deprecated) You assigned a non-C<undef> value to C<${^ENCODING}>.
5459 This is deprecated; see C<L<perlvar/${^ENCODING}>> for details.
5461 =item Setting $/ to a reference to %s as a form of slurp is deprecated, treating as undef
5463 (D deprecated) You assigned a reference to a scalar to C<$/> where the
5464 referenced item is not a positive integer. In older perls this B<appeared>
5465 to work the same as setting it to C<undef> but was in fact internally
5466 different, less efficient and with very bad luck could have resulted in
5467 your file being split by a stringified form of the reference.
5469 In Perl 5.20.0 this was changed so that it would be B<exactly> the same as
5470 setting C<$/> to undef, with the exception that this warning would be
5473 You are recommended to change your code to set C<$/> to C<undef> explicitly
5474 if you wish to slurp the file. In future versions of Perl assigning
5475 a reference to will throw a fatal error.
5477 =item Setting $/ to %s reference is forbidden
5479 (F) You tried to assign a reference to a non integer to C<$/>. In older
5480 Perls this would have behaved similarly to setting it to a reference to
5481 a positive integer, where the integer was the address of the reference.
5482 As of Perl 5.20.0 this is a fatal error, to allow future versions of Perl
5483 to use non-integer refs for more interesting purposes.
5485 =item shm%s not implemented
5487 (F) You don't have System V shared memory IPC on your system.
5489 =item !=~ should be !~
5491 (W syntax) The non-matching operator is !~, not !=~. !=~ will be
5492 interpreted as the != (numeric not equal) and ~ (1's complement)
5493 operators: probably not what you intended.
5495 =item /%s/ should probably be written as "%s"
5497 (W syntax) You have used a pattern where Perl expected to find a string,
5498 as in the first argument to C<join>. Perl will treat the true or false
5499 result of matching the pattern against $_ as the string, which is
5500 probably not what you had in mind.
5502 =item shutdown() on closed socket %s
5504 (W closed) You tried to do a shutdown on a closed socket. Seems a bit
5507 =item SIG%s handler "%s" not defined
5509 (W signal) The signal handler named in %SIG doesn't, in fact, exist.
5510 Perhaps you put it into the wrong package?
5512 =item Slab leaked from cv %p
5514 (S) If you see this message, then something is seriously wrong with the
5515 internal bookkeeping of op trees. An op tree needed to be freed after
5516 a compilation error, but could not be found, so it was leaked instead.
5518 =item sleep(%u) too large
5520 (W overflow) You called C<sleep> with a number that was larger than
5521 it can reliably handle and C<sleep> probably slept for less time than
5524 =item Slurpy parameter not last
5526 (F) In a subroutine signature, you put something after a slurpy (array or
5527 hash) parameter. The slurpy parameter takes all the available arguments,
5528 so there can't be any left to fill later parameters.
5530 =item Smart matching a non-overloaded object breaks encapsulation
5532 (F) You should not use the C<~~> operator on an object that does not
5533 overload it: Perl refuses to use the object's underlying structure
5534 for the smart match.
5536 =item Smartmatch is experimental
5538 (S experimental::smartmatch) This warning is emitted if you
5539 use the smartmatch (C<~~>) operator. This is currently an experimental
5540 feature, and its details are subject to change in future releases of
5541 Perl. Particularly, its current behavior is noticed for being
5542 unnecessarily complex and unintuitive, and is very likely to be
5545 =item sort is now a reserved word
5547 (F) An ancient error message that almost nobody ever runs into anymore.
5548 But before sort was a keyword, people sometimes used it as a filehandle.
5550 =item Source filters apply only to byte streams
5552 (F) You tried to activate a source filter (usually by loading a
5553 source filter module) within a string passed to C<eval>. This is
5554 not permitted under the C<unicode_eval> feature. Consider using
5555 C<evalbytes> instead. See L<feature>.
5557 =item splice() offset past end of array
5559 (W misc) You attempted to specify an offset that was past the end of
5560 the array passed to splice(). Splicing will instead commence at the
5561 end of the array, rather than past it. If this isn't what you want,
5562 try explicitly pre-extending the array by assigning $#array = $offset.
5563 See L<perlfunc/splice>.
5567 (P) The split was looping infinitely. (Obviously, a split shouldn't
5568 iterate more times than there are characters of input, which is what
5569 happened.) See L<perlfunc/split>.
5571 =item Statement unlikely to be reached
5573 (W exec) You did an exec() with some statement after it other than a
5574 die(). This is almost always an error, because exec() never returns
5575 unless there was a failure. You probably wanted to use system()
5576 instead, which does return. To suppress this warning, put the exec() in
5579 =item "state" subroutine %s can't be in a package
5581 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
5582 sense to try to declare one with a package qualifier on the front.
5584 =item "state %s" used in sort comparison
5586 (W syntax) The package variables $a and $b are used for sort comparisons.
5587 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
5588 sort comparison block, and the variable had earlier been declared as a
5589 lexical variable. Either qualify the sort variable with the package
5590 name, or rename the lexical variable.
5592 =item "state" variable %s can't be in a package
5594 (F) Lexically scoped variables aren't in a package, so it doesn't make
5595 sense to try to declare one with a package qualifier on the front. Use
5596 local() if you want to localize a package variable.
5598 =item stat() on unopened filehandle %s
5600 (W unopened) You tried to use the stat() function on a filehandle that
5601 was either never opened or has since been closed.
5603 =item Strings with code points over 0xFF may not be mapped into in-memory file handles
5605 (W utf8) You tried to open a reference to a scalar for read or append
5606 where the scalar contained code points over 0xFF. In-memory files
5607 model on-disk files and can only contain bytes.
5609 =item Stub found while resolving method "%s" overloading "%s" in package "%s"
5611 (P) Overloading resolution over @ISA tree may be broken by importation
5612 stubs. Stubs should never be implicitly created, but explicit calls to
5613 C<can> may break this.
5615 =item Subroutine "&%s" is not available
5617 (W closure) During compilation, an inner named subroutine or eval is
5618 attempting to capture an outer lexical subroutine that is not currently
5619 available. This can happen for one of two reasons. First, the lexical
5620 subroutine may be declared in an outer anonymous subroutine that has
5621 not yet been created. (Remember that named subs are created at compile
5622 time, while anonymous subs are created at run-time.) For example,
5624 sub { my sub a {...} sub f { \&a } }
5626 At the time that f is created, it can't capture the current "a" sub,
5627 since the anonymous subroutine hasn't been created yet. Conversely, the
5628 following won't give a warning since the anonymous subroutine has by now
5629 been created and is live:
5631 sub { my sub a {...} eval 'sub f { \&a }' }->();
5633 The second situation is caused by an eval accessing a lexical subroutine
5634 that has gone out of scope, for example,
5642 Here, when the '\&a' in the eval is being compiled, f() is not currently
5643 being executed, so its &a is not available for capture.
5645 =item "%s" subroutine &%s masks earlier declaration in same %s
5647 (W misc) A "my" or "state" subroutine has been redeclared in the
5648 current scope or statement, effectively eliminating all access to
5649 the previous instance. This is almost always a typographical error.
5650 Note that the earlier subroutine will still exist until the end of
5651 the scope or until all closure references to it are destroyed.
5653 =item Subroutine %s redefined
5655 (W redefine) You redefined a subroutine. To suppress this warning, say
5658 no warnings 'redefine';
5659 eval "sub name { ... }";
5662 =item Subroutine "%s" will not stay shared
5664 (W closure) An inner (nested) I<named> subroutine is referencing a "my"
5665 subroutine defined in an outer named subroutine.
5667 When the inner subroutine is called, it will see the value of the outer
5668 subroutine's lexical subroutine as it was before and during the *first*
5669 call to the outer subroutine; in this case, after the first call to the
5670 outer subroutine is complete, the inner and outer subroutines will no
5671 longer share a common value for the lexical subroutine. In other words,
5672 it will no longer be shared. This will especially make a difference
5673 if the lexical subroutines accesses lexical variables declared in its
5676 This problem can usually be solved by making the inner subroutine
5677 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
5678 reference lexical subroutines in outer subroutines are created, they
5679 are automatically rebound to the current values of such lexical subs.
5681 =item Substitution loop
5683 (P) The substitution was looping infinitely. (Obviously, a substitution
5684 shouldn't iterate more times than there are characters of input, which
5685 is what happened.) See the discussion of substitution in
5686 L<perlop/"Regexp Quote-Like Operators">.
5688 =item Substitution pattern not terminated
5690 (F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
5691 construct. Remember that bracketing delimiters count nesting level.
5692 Missing the leading C<$> from variable C<$s> may cause this error.
5694 =item Substitution replacement not terminated
5696 (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
5697 construct. Remember that bracketing delimiters count nesting level.
5698 Missing the leading C<$> from variable C<$s> may cause this error.
5700 =item substr outside of string
5702 (W substr)(F) You tried to reference a substr() that pointed outside of
5703 a string. That is, the absolute value of the offset was larger than the
5704 length of the string. See L<perlfunc/substr>. This warning is fatal if
5705 substr is used in an lvalue context (as the left hand side of an
5706 assignment or as a subroutine argument for example).
5708 =item sv_upgrade from type %d down to type %d
5710 (P) Perl tried to force the upgrade of an SV to a type which was actually
5711 inferior to its current type.
5713 =item SWASHNEW didn't return an HV ref
5715 (P) Something went wrong internally when Perl was trying to look up
5718 =item Switch (?(condition)... contains too many branches in regex; marked by
5719 S<<-- HERE> in m/%s/
5721 (F) A (?(condition)if-clause|else-clause) construct can have at most
5722 two branches (the if-clause and the else-clause). If you want one or
5723 both to contain alternation, such as using C<this|that|other>, enclose
5724 it in clustering parentheses:
5726 (?(condition)(?:this|that|other)|else-clause)
5728 The S<<-- HERE> shows whereabouts in the regular expression the problem
5729 was discovered. See L<perlre>.
5731 =item Switch condition not recognized in regex; marked by S<<-- HERE> in
5734 (F) The condition part of a (?(condition)if-clause|else-clause) construct
5735 is not known. The condition must be one of the following:
5737 (1) (2) ... true if 1st, 2nd, etc., capture matched
5738 (<NAME>) ('NAME') true if named capture matched
5739 (?=...) (?<=...) true if subpattern matches
5740 (?!...) (?<!...) true if subpattern fails to match
5741 (?{ CODE }) true if code returns a true value
5742 (R) true if evaluating inside recursion
5743 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
5744 (R&NAME) true if directly inside named capture
5745 (DEFINE) always false; for defining named subpatterns
5747 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5748 discovered. See L<perlre>.
5750 =item Switch (?(condition)... not terminated in regex; marked by
5751 S<<-- HERE> in m/%s/
5753 (F) You omitted to close a (?(condition)...) block somewhere
5754 in the pattern. Add a closing parenthesis in the appropriate
5755 position. See L<perlre>.
5757 =item switching effective %s is not implemented
5759 (F) While under the C<use filetest> pragma, we cannot switch the real
5760 and effective uids or gids.
5764 (F) Probably means you had a syntax error. Common reasons include:
5766 A keyword is misspelled.
5767 A semicolon is missing.
5769 An opening or closing parenthesis is missing.
5770 An opening or closing brace is missing.
5771 A closing quote is missing.
5773 Often there will be another error message associated with the syntax
5774 error giving more information. (Sometimes it helps to turn on B<-w>.)
5775 The error message itself often tells you where it was in the line when
5776 it decided to give up. Sometimes the actual error is several tokens
5777 before this, because Perl is good at understanding random input.
5778 Occasionally the line number may be misleading, and once in a blue moon
5779 the only way to figure out what's triggering the error is to call
5780 C<perl -c> repeatedly, chopping away half the program each time to see
5781 if the error went away. Sort of the cybernetic version of S<20 questions>.
5783 =item syntax error at line %d: '%s' unexpected
5785 (A) You've accidentally run your script through the Bourne shell instead
5786 of Perl. Check the #! line, or manually feed your script into Perl
5789 =item syntax error in file %s at line %d, next 2 tokens "%s"
5791 (F) This error is likely to occur if you run a perl5 script through
5792 a perl4 interpreter, especially if the next 2 tokens are "use strict"
5793 or "my $var" or "our $var".
5795 =item Syntax error in (?[...]) in regex m/%s/
5797 (F) Perl could not figure out what you meant inside this construct; this
5798 notifies you that it is giving up trying.
5802 (F) The final summary message when a C<perl -c> succeeds.
5804 =item sysread() on closed filehandle %s
5806 (W closed) You tried to read from a closed filehandle.
5808 =item sysread() on unopened filehandle %s
5810 (W unopened) You tried to read from a filehandle that was never opened.
5812 =item System V %s is not implemented on this machine
5814 (F) You tried to do something with a function beginning with "sem",
5815 "shm", or "msg" but that System V IPC is not implemented in your
5816 machine. In some machines the functionality can exist but be
5817 unconfigured. Consult your system support.
5819 =item syswrite() on closed filehandle %s
5821 (W closed) The filehandle you're writing to got itself closed sometime
5822 before now. Check your control flow.
5824 =item C<-T> and C<-B> not implemented on filehandles
5826 (F) Perl can't peek at the stdio buffer of filehandles when it doesn't
5827 know about your kind of stdio. You'll have to use a filename instead.
5829 =item Target of goto is too deeply nested
5831 (F) You tried to use C<goto> to reach a label that was too deeply nested
5832 for Perl to reach. Perl is doing you a favor by refusing.
5834 =item telldir() attempted on invalid dirhandle %s
5836 (W io) The dirhandle you tried to telldir() is either closed or not really
5837 a dirhandle. Check your control flow.
5839 =item tell() on unopened filehandle
5841 (W unopened) You tried to use the tell() function on a filehandle that
5842 was either never opened or has since been closed.
5844 =item That use of $[ is unsupported
5846 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
5847 as a compiler directive. You may say only one of
5856 This is to prevent the problem of one module changing the array base out
5857 from under another module inadvertently. See L<perlvar/$[> and L<arybase>.
5859 =item The bitwise feature is experimental
5861 (S experimental::bitwise) This warning is emitted if you use bitwise
5862 operators (C<& | ^ ~ &. |. ^. ~.>) with the "bitwise" feature enabled.
5863 Simply suppress the warning if you want to use the feature, but know
5864 that in doing so you are taking the risk of using an experimental
5865 feature which may change or be removed in a future Perl version:
5867 no warnings "experimental::bitwise";
5868 use feature "bitwise";
5871 =item The crypt() function is unimplemented due to excessive paranoia.
5873 (F) Configure couldn't find the crypt() function on your machine,
5874 probably because your vendor didn't supply it, probably because they
5875 think the U.S. Government thinks it's a secret, or at least that they
5876 will continue to pretend that it is. And if you quote me on that, I
5879 =item The %s function is unimplemented
5881 (F) The function indicated isn't implemented on this architecture,
5882 according to the probings of Configure.
5884 =item The regex_sets feature is experimental
5886 (S experimental::regex_sets) This warning is emitted if you
5887 use the syntax S<C<(?[ ])>> in a regular expression.
5888 The details of this feature are subject to change.
5889 if you want to use it, but know that in doing so you
5890 are taking the risk of using an experimental feature which may
5891 change in a future Perl version, you can do this to silence the
5894 no warnings "experimental::regex_sets";
5896 =item The signatures feature is experimental
5898 (S experimental::signatures) This warning is emitted if you unwrap a
5899 subroutine's arguments using a signature. Simply suppress the warning
5900 if you want to use the feature, but know that in doing so you are taking
5901 the risk of using an experimental feature which may change or be removed
5902 in a future Perl version:
5904 no warnings "experimental::signatures";
5905 use feature "signatures";
5906 sub foo ($left, $right) { ... }
5908 =item The stat preceding %s wasn't an lstat
5910 (F) It makes no sense to test the current stat buffer for symbolic
5911 linkhood if the last stat that wrote to the stat buffer already went
5912 past the symlink to get to the real file. Use an actual filename
5915 =item The 'unique' attribute may only be applied to 'our' variables
5917 (F) This attribute was never supported on C<my> or C<sub> declarations.
5919 =item This Perl can't reset CRTL environ elements (%s)
5921 =item This Perl can't set CRTL environ elements (%s=%s)
5923 (W internal) Warnings peculiar to VMS. You tried to change or delete an
5924 element of the CRTL's internal environ array, but your copy of Perl
5925 wasn't built with a CRTL that contained the setenv() function. You'll
5926 need to rebuild Perl with a CRTL that does, or redefine
5927 F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
5928 target of the change to
5929 %ENV which produced the warning.
5931 =item This Perl has not been built with support for randomized hash key traversal but something called Perl_hv_rand_set().
5933 (F) Something has attempted to use an internal API call which
5934 depends on Perl being compiled with the default support for randomized hash
5935 key traversal, but this Perl has been compiled without it. You should
5936 report this warning to the relevant upstream party, or recompile perl
5937 with default options.
5939 =item times not implemented
5941 (F) Your version of the C library apparently doesn't do times(). I
5942 suspect you're not running on Unix.
5944 =item "-T" is on the #! line, it must also be used on the command line
5946 (X) The #! line (or local equivalent) in a Perl script contains
5947 the B<-T> option (or the B<-t> option), but Perl was not invoked with
5948 B<-T> in its command line. This is an error because, by the time
5949 Perl discovers a B<-T> in a script, it's too late to properly taint
5950 everything from the environment. So Perl gives up.
5952 If the Perl script is being executed as a command using the #!
5953 mechanism (or its local equivalent), this error can usually be
5954 fixed by editing the #! line so that the B<-%c> option is a part of
5955 Perl's first argument: e.g. change C<perl -n -%c> to C<perl -%c -n>.
5957 If the Perl script is being executed as C<perl scriptname>, then the
5958 B<-%c> option must appear on the command line: C<perl -%c scriptname>.
5960 =item To%s: illegal mapping '%s'
5962 (F) You tried to define a customized To-mapping for lc(), lcfirst,
5963 uc(), or ucfirst() (or their string-inlined versions), but you
5964 specified an illegal mapping.
5965 See L<perlunicode/"User-Defined Character Properties">.
5967 =item Too deeply nested ()-groups
5969 (F) Your template contains ()-groups with a ridiculously deep nesting level.
5971 =item Too few args to syscall
5973 (F) There has to be at least one argument to syscall() to specify the
5974 system call to call, silly dilly.
5976 =item Too few arguments for subroutine
5978 (F) A subroutine using a signature received fewer arguments than required
5979 by the signature. The caller of the subroutine is presumably at fault.
5980 Inconveniently, this error will be reported at the location of the
5981 subroutine, not that of the caller.
5983 =item Too late for "-%s" option
5985 (X) The #! line (or local equivalent) in a Perl script contains the
5986 B<-M>, B<-m> or B<-C> option.
5988 In the case of B<-M> and B<-m>, this is an error because those options
5989 are not intended for use inside scripts. Use the C<use> pragma instead.
5991 The B<-C> option only works if it is specified on the command line as
5992 well (with the same sequence of letters or numbers following). Either
5993 specify this option on the command line, or, if your system supports
5994 it, make your script executable and run it directly instead of passing
5997 =item Too late to run %s block
5999 (W void) A CHECK or INIT block is being defined during run time proper,
6000 when the opportunity to run them has already passed. Perhaps you are
6001 loading a file with C<require> or C<do> when you should be using C<use>
6002 instead. Or perhaps you should put the C<require> or C<do> inside a
6005 =item Too many args to syscall
6007 (F) Perl supports a maximum of only 14 args to syscall().
6009 =item Too many arguments for %s
6011 (F) The function requires fewer arguments than you specified.
6013 =item Too many arguments for subroutine
6015 (F) A subroutine using a signature received more arguments than required
6016 by the signature. The caller of the subroutine is presumably at fault.
6017 Inconveniently, this error will be reported at the location of the
6018 subroutine, not that of the caller.
6022 (A) You've accidentally run your script through B<csh> instead of Perl.
6023 Check the #! line, or manually feed your script into Perl yourself.
6027 (A) You've accidentally run your script through B<csh> instead of Perl.
6028 Check the #! line, or manually feed your script into Perl yourself.
6030 =item Trailing \ in regex m/%s/
6032 (F) The regular expression ends with an unbackslashed backslash.
6033 Backslash it. See L<perlre>.
6035 =item Transliteration pattern not terminated
6037 (F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
6038 or y/// or y[][] construct. Missing the leading C<$> from variables
6039 C<$tr> or C<$y> may cause this error.
6041 =item Transliteration replacement not terminated
6043 (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
6044 y/// or y[][] construct.
6046 =item '%s' trapped by operation mask
6048 (F) You tried to use an operator from a Safe compartment in which it's
6049 disallowed. See L<Safe>.
6051 =item truncate not implemented
6053 (F) Your machine doesn't implement a file truncation mechanism that
6054 Configure knows about.
6056 =item Type of arg %d to &CORE::%s must be %s
6058 (F) The subroutine in question in the CORE package requires its argument
6059 to be a hard reference to data of the specified type. Overloading is
6060 ignored, so a reference to an object that is not the specified type, but
6061 nonetheless has overloading to handle it, will still not be accepted.
6063 =item Type of arg %d to %s must be %s (not %s)
6065 (F) This function requires the argument in that position to be of a
6066 certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
6067 %NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
6068 {EXPR} forms as an explicit dereference. See L<perlref>.
6070 =item umask not implemented
6072 (F) Your machine doesn't implement the umask function and you tried to
6073 use it to restrict permissions for yourself (EXPR & 0700).
6075 =item Unbalanced context: %d more PUSHes than POPs
6077 (S internal) The exit code detected an internal inconsistency in how
6078 many execution contexts were entered and left.
6080 =item Unbalanced saves: %d more saves than restores
6082 (S internal) The exit code detected an internal inconsistency in how
6083 many values were temporarily localized.
6085 =item Unbalanced scopes: %d more ENTERs than LEAVEs
6087 (S internal) The exit code detected an internal inconsistency in how
6088 many blocks were entered and left.
6090 =item Unbalanced string table refcount: (%d) for "%s"
6092 (S internal) On exit, Perl found some strings remaining in the shared
6093 string table used for copy on write and for hash keys. The entries
6094 should have been freed, so this indicates a bug somewhere.
6096 =item Unbalanced tmps: %d more allocs than frees
6098 (S internal) The exit code detected an internal inconsistency in how
6099 many mortal scalars were allocated and freed.
6101 =item Undefined format "%s" called
6103 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6104 another package? See L<perlform>.
6106 =item Undefined sort subroutine "%s" called
6108 (F) The sort comparison routine specified doesn't seem to exist.
6109 Perhaps it's in a different package? See L<perlfunc/sort>.
6111 =item Undefined subroutine &%s called
6113 (F) The subroutine indicated hasn't been defined, or if it was, it has
6114 since been undefined.
6116 =item Undefined subroutine called
6118 (F) The anonymous subroutine you're trying to call hasn't been defined,
6119 or if it was, it has since been undefined.
6121 =item Undefined subroutine in sort
6123 (F) The sort comparison routine specified is declared but doesn't seem
6124 to have been defined yet. See L<perlfunc/sort>.
6126 =item Undefined top format "%s" called
6128 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6129 another package? See L<perlform>.
6131 =item Undefined value assigned to typeglob
6133 (W misc) An undefined value was assigned to a typeglob, a la
6134 C<*foo = undef>. This does nothing. It's possible that you really mean
6137 =item %s: Undefined variable
6139 (A) You've accidentally run your script through B<csh> instead of Perl.
6140 Check the #! line, or manually feed your script into Perl yourself.
6142 =item Unescaped left brace in regex is deprecated here, passed through in
6143 regex; marked by S<<-- HERE> in m/%s/
6145 (D deprecated, regexp) The simple rule to remember, if you want to
6146 match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
6147 regular expression pattern, is to escape each literal instance of it in
6148 some way. Generally easiest is to precede it with a backslash, like
6149 C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
6150 delimiters are also braces, any matching right brace (C<"}">) should
6151 also be escaped to avoid confusing the parser, for example,
6155 Forcing literal C<"{"> characters to be escaped will enable the Perl
6156 language to be extended in various ways in future releases. To avoid
6157 needlessly breaking existing code, the restriction is is not enforced in
6158 contexts where there are unlikely to ever be extensions that could
6159 conflict with the use there of C<"{"> as a literal.
6161 In this release of Perl, some literal uses of C<"{"> are fatal, and some
6162 still just deprecated. This is because of an oversight: some uses of a
6163 literal C<"{"> that should have raised a deprecation warning starting in
6164 v5.20 did not warn until v5.26. By making the already-warned uses fatal
6165 now, some of the planned extensions can be made to the language sooner.
6167 The contexts where no warnings or errors are raised are:
6173 as the first character in a pattern, or following C<"^"> indicating to
6174 anchor the match to the beginning of a line.
6178 as the first character following a C<"|"> indicating alternation.
6182 as the first character in a parenthesized grouping like
6189 as the first character following a quantifier
6196 The text of the message above is duplicated below to allow splain (and
6197 'use diagnostics') to work. Since one is fatal, and one not, they can't
6198 be combined as one message. And since the non-fatal one is temporary,
6199 there's no real need to enhance perldiag to handle this transient case.
6201 =item Unescaped left brace in regex is illegal here in regex;
6202 marked by S<<-- HERE> in m/%s/
6204 (F) The simple rule to remember, if you want to
6205 match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
6206 regular expression pattern, is to escape each literal instance of it in
6207 some way. Generally easiest is to precede it with a backslash, like
6208 C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
6209 delimiters are also braces, any matching right brace (C<"}">) should
6210 also be escaped to avoid confusing the parser, for example,
6214 Forcing literal C<"{"> characters to be escaped will enable the Perl
6215 language to be extended in various ways in future releases. To avoid
6216 needlessly breaking existing code, the restriction is is not enforced in
6217 contexts where there are unlikely to ever be extensions that could
6218 conflict with the use there of C<"{"> as a literal.
6220 In this release of Perl, some literal uses of C<"{"> are fatal, and some
6221 still just deprecated. This is because of an oversight: some uses of a
6222 literal C<"{"> that should have raised a deprecation warning starting in
6223 v5.20 did not warn until v5.26. By making the already-warned uses fatal
6224 now, some of the planned extensions can be made to the language sooner.
6226 The contexts where no warnings or errors are raised are:
6232 as the first character in a pattern, or following C<"^"> indicating to
6233 anchor the match to the beginning of a line.
6237 as the first character following a C<"|"> indicating alternation.
6241 as the first character in a parenthesized grouping like
6248 as the first character following a quantifier
6254 =item unexec of %s into %s failed!
6256 (F) The unexec() routine failed for some reason. See your local FSF
6257 representative, who probably put it there in the first place.
6259 =item Unexpected binary operator '%c' with no preceding operand in regex;
6260 marked by S<<-- HERE> in m/%s/
6262 (F) You had something like this:
6266 where the C<"|"> is a binary operator with an operand on the right, but
6267 no operand on the left.
6269 =item Unexpected character in regex; marked by S<<-- HERE> in m/%s/
6271 (F) You had something like this:
6275 Within C<(?[ ])>, no literal characters are allowed unless they are
6276 within an inner pair of square brackets, like
6280 Another possibility is that you forgot a backslash. Perl isn't smart
6281 enough to figure out what you really meant.
6283 =item Unexpected constant lvalue entersub entry via type/targ %d:%d
6285 (P) When compiling a subroutine call in lvalue context, Perl failed an
6286 internal consistency check. It encountered a malformed op tree.
6288 =item Unexpected exit %u
6290 (S) exit() was called or the script otherwise finished gracefully when
6291 C<PERL_EXIT_WARN> was set in C<PL_exit_flags>.
6293 =item Unexpected exit failure %d
6295 (S) An uncaught die() was called when C<PERL_EXIT_WARN> was set in
6298 =item Unexpected ')' in regex; marked by S<<-- HERE> in m/%s/
6300 (F) You had something like this:
6302 (?[ ( \p{Digit} + ) ])
6304 The C<")"> is out-of-place. Something apparently was supposed to
6305 be combined with the digits, or the C<"+"> shouldn't be there, or
6306 something like that. Perl can't figure out what was intended.
6308 =item Unexpected '(' with no preceding operator in regex; marked by
6309 S<<-- HERE> in m/%s/
6311 (F) You had something like this:
6313 (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
6315 There should be an operator before the C<"(">, as there's
6316 no indication as to how the digits are to be combined
6317 with the characters in the Lao and Thai scripts.
6319 =item Unicode non-character U+%X is not recommended for open interchange
6321 (S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
6322 defined by the Unicode standard to be non-characters. Those
6323 are legal codepoints, but are reserved for internal use; so,
6324 applications shouldn't attempt to exchange them. An application
6325 may not be expecting any of these characters at all, and receiving
6326 them may lead to bugs. If you know what you are doing you can
6327 turn off this warning by C<no warnings 'nonchar';>.
6329 This is not really a "severe" error, but it is supposed to be
6330 raised by default even if warnings are not enabled, and currently
6331 the only way to do that in Perl is to mark it as serious.
6333 =item Unicode surrogate U+%X is illegal in UTF-8
6335 (S surrogate) You had a UTF-16 surrogate in a context where they are
6336 not considered acceptable. These code points, between U+D800 and
6337 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6338 internally allows all unsigned integer code points (up to the size limit
6339 available on your platform), including surrogates. But these can cause
6340 problems when being input or output, which is likely where this message
6341 came from. If you really really know what you are doing you can turn
6342 off this warning by C<no warnings 'surrogate';>.
6344 =item Unknown charname '%s'
6346 (F) The name you used inside C<\N{}> is unknown to Perl. Check the
6347 spelling. You can say C<use charnames ":loose"> to not have to be
6348 so precise about spaces, hyphens, and capitalization on standard Unicode
6349 names. (Any custom aliases that have been created must be specified
6350 exactly, regardless of whether C<:loose> is used or not.) This error may
6351 also happen if the C<\N{}> is not in the scope of the corresponding
6352 C<S<use charnames>>.
6354 =item Unknown charname '' is deprecated
6356 (D deprecated) You had a C<\N{}> with nothing between the braces. This
6357 usage is deprecated, and will be made a syntax error in a future Perl
6362 (P) Perl was about to print an error message in C<$@>, but the C<$@> variable
6363 did not exist, even after an attempt to create it.
6365 =item Unknown open() mode '%s'
6367 (F) The second argument of 3-argument open() is not among the list
6368 of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
6369 C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
6371 =item Unknown PerlIO layer "%s"
6373 (W layer) An attempt was made to push an unknown layer onto the Perl I/O
6374 system. (Layers take care of transforming data between external and
6375 internal representations.) Note that some layers, such as C<mmap>,
6376 are not supported in all environments. If your program didn't
6377 explicitly request the failing operation, it may be the result of the
6378 value of the environment variable PERLIO.
6380 =item Unknown process %x sent message to prime_env_iter: %s
6382 (P) An error peculiar to VMS. Perl was reading values for %ENV before
6383 iterating over it, and someone else stuck a message in the stream of
6384 data Perl expected. Someone's very confused, or perhaps trying to
6385 subvert Perl's population of %ENV for nefarious purposes.
6387 =item Unknown regex modifier "%s"
6389 (F) Alphanumerics immediately following the closing delimiter
6390 of a regular expression pattern are interpreted by Perl as modifier
6391 flags for the regex. One of the ones you specified is invalid. One way
6392 this can happen is if you didn't put in white space between the end of
6393 the regex and a following alphanumeric operator:
6395 if ($a =~ /foo/and $bar == 3) { ... }
6397 The C<"a"> is a valid modifier flag, but the C<"n"> is not, and raises
6398 this error. Likely what was meant instead was:
6400 if ($a =~ /foo/ and $bar == 3) { ... }
6402 =item Unknown "re" subpragma '%s' (known ones are: %s)
6404 (W) You tried to use an unknown subpragma of the "re" pragma.
6406 =item Unknown switch condition (?(...)) in regex; marked by S<<-- HERE> in
6409 (F) The condition part of a (?(condition)if-clause|else-clause) construct
6410 is not known. The condition must be one of the following:
6412 (1) (2) ... true if 1st, 2nd, etc., capture matched
6413 (<NAME>) ('NAME') true if named capture matched
6414 (?=...) (?<=...) true if subpattern matches
6415 (?!...) (?<!...) true if subpattern fails to match
6416 (?{ CODE }) true if code returns a true value
6417 (R) true if evaluating inside recursion
6418 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
6419 (R&NAME) true if directly inside named capture
6420 (DEFINE) always false; for defining named subpatterns
6422 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6423 discovered. See L<perlre>.
6425 =item Unknown Unicode option letter '%c'
6427 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6428 of the C<-C> switch for the list of known options.
6430 =item Unknown Unicode option value %d
6432 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6433 of the C<-C> switch for the list of known options.
6435 =item Unknown verb pattern '%s' in regex; marked by S<<-- HERE> in m/%s/
6437 (F) You either made a typo or have incorrectly put a C<*> quantifier
6438 after an open brace in your pattern. Check the pattern and review
6439 L<perlre> for details on legal verb patterns.
6441 =item Unknown warnings category '%s'
6443 (F) An error issued by the C<warnings> pragma. You specified a warnings
6444 category that is unknown to perl at this point.
6446 Note that if you want to enable a warnings category registered by a
6447 module (e.g. C<use warnings 'File::Find'>), you must have loaded this
6450 =item Unmatched [ in regex; marked by S<<-- HERE> in m/%s/
6452 (F) The brackets around a character class must match. If you wish to
6453 include a closing bracket in a character class, backslash it or put it
6454 first. The S<<-- HERE> shows whereabouts in the regular expression the
6455 problem was discovered. See L<perlre>.
6457 =item Unmatched ( in regex; marked by S<<-- HERE> in m/%s/
6459 =item Unmatched ) in regex; marked by S<<-- HERE> in m/%s/
6461 (F) Unbackslashed parentheses must always be balanced in regular
6462 expressions. If you're a vi user, the % key is valuable for finding
6463 the matching parenthesis. The S<<-- HERE> shows whereabouts in the
6464 regular expression the problem was discovered. See L<perlre>.
6466 =item Unmatched right %s bracket
6468 (F) The lexer counted more closing curly or square brackets than opening
6469 ones, so you're probably missing a matching opening bracket. As a
6470 general rule, you'll find the missing one (so to speak) near the place
6471 you were last editing.
6473 =item Unquoted string "%s" may clash with future reserved word
6475 (W reserved) You used a bareword that might someday be claimed as a
6476 reserved word. It's best to put such a word in quotes, or capitalize it
6477 somehow, or insert an underbar into it. You might also declare it as a
6480 =item Unrecognized character %s; marked by S<<-- HERE> after %s near column
6483 (F) The Perl parser has no idea what to do with the specified character
6484 in your Perl script (or eval) near the specified column. Perhaps you
6485 tried to run a compressed script, a binary program, or a directory as
6488 =item Unrecognized escape \%c in character class in regex; marked by
6489 S<<-- HERE> in m/%s/
6491 (F) You used a backslash-character combination which is not
6492 recognized by Perl inside character classes. This is a fatal
6493 error when the character class is used within C<(?[ ])>.
6495 =item Unrecognized escape \%c in character class passed through in regex;
6496 marked by S<<-- HERE> in m/%s/
6498 (W regexp) You used a backslash-character combination which is not
6499 recognized by Perl inside character classes. The character was
6500 understood literally, but this may change in a future version of Perl.
6501 The S<<-- HERE> shows whereabouts in the regular expression the
6502 escape was discovered.
6504 =item Unrecognized escape \%c passed through
6506 (W misc) You used a backslash-character combination which is not
6507 recognized by Perl. The character was understood literally, but this may
6508 change in a future version of Perl.
6510 =item Unrecognized escape \%s passed through in regex; marked by
6511 S<<-- HERE> in m/%s/
6513 (W regexp) You used a backslash-character combination which is not
6514 recognized by Perl. The character(s) were understood literally, but
6515 this may change in a future version of Perl. The S<<-- HERE> shows
6516 whereabouts in the regular expression the escape was discovered.
6518 =item Unrecognized signal name "%s"
6520 (F) You specified a signal name to the kill() function that was not
6521 recognized. Say C<kill -l> in your shell to see the valid signal names
6524 =item Unrecognized switch: -%s (-h will show valid options)
6526 (F) You specified an illegal option to Perl. Don't do that. (If you
6527 think you didn't do that, check the #! line to see if it's supplying the
6528 bad switch on your behalf.)
6530 =item Unsuccessful %s on filename containing newline
6532 (W newline) A file operation was attempted on a filename, and that
6533 operation failed, PROBABLY because the filename contained a newline,
6534 PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
6536 =item Unsupported directory function "%s" called
6538 (F) Your machine doesn't support opendir() and readdir().
6540 =item Unsupported function %s
6542 (F) This machine doesn't implement the indicated function, apparently.
6543 At least, Configure doesn't think so.
6545 =item Unsupported function fork
6547 (F) Your version of executable does not support forking.
6549 Note that under some systems, like OS/2, there may be different flavors
6550 of Perl executables, some of which may support fork, some not. Try
6551 changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
6553 =item Unsupported script encoding %s
6555 (F) Your program file begins with a Unicode Byte Order Mark (BOM) which
6556 declares it to be in a Unicode encoding that Perl cannot read.
6558 =item Unsupported socket function "%s" called
6560 (F) Your machine doesn't support the Berkeley socket mechanism, or at
6561 least that's what Configure thought.
6563 =item Unterminated attribute list
6565 (F) The lexer found something other than a simple identifier at the
6566 start of an attribute, and it wasn't a semicolon or the start of a
6567 block. Perhaps you terminated the parameter list of the previous
6568 attribute too soon. See L<attributes>.
6570 =item Unterminated attribute parameter in attribute list
6572 (F) The lexer saw an opening (left) parenthesis character while parsing
6573 an attribute list, but the matching closing (right) parenthesis
6574 character was not found. You may need to add (or remove) a backslash
6575 character to get your parentheses to balance. See L<attributes>.
6577 =item Unterminated compressed integer
6579 (F) An argument to unpack("w",...) was incompatible with the BER
6580 compressed integer format and could not be converted to an integer.
6581 See L<perlfunc/pack>.
6583 =item Unterminated delimiter for here document
6585 (F) This message occurs when a here document label has an initial
6586 quotation mark but the final quotation mark is missing. Perhaps
6595 =item Unterminated \g... pattern in regex; marked by S<<-- HERE> in m/%s/
6597 =item Unterminated \g{...} pattern in regex; marked by S<<-- HERE> in m/%s/
6599 (F) In a regular expression, you had a C<\g> that wasn't followed by a
6600 proper group reference. In the case of C<\g{>, the closing brace is
6601 missing; otherwise the C<\g> must be followed by an integer. Fix the
6604 =item Unterminated <> operator
6606 (F) The lexer saw a left angle bracket in a place where it was expecting
6607 a term, so it's looking for the corresponding right angle bracket, and
6608 not finding it. Chances are you left some needed parentheses out
6609 earlier in the line, and you really meant a "less than".
6611 =item Unterminated verb pattern argument in regex; marked by S<<-- HERE> in
6614 (F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
6615 the pattern with a C<)>. Fix the pattern and retry.
6617 =item Unterminated verb pattern in regex; marked by S<<-- HERE> in m/%s/
6619 (F) You used a pattern of the form C<(*VERB)> but did not terminate
6620 the pattern with a C<)>. Fix the pattern and retry.
6622 =item untie attempted while %d inner references still exist
6624 (W untie) A copy of the object returned from C<tie> (or C<tied>) was
6625 still valid when C<untie> was called.
6627 =item Usage: POSIX::%s(%s)
6629 (F) You called a POSIX function with incorrect arguments.
6630 See L<POSIX/FUNCTIONS> for more information.
6632 =item Usage: Win32::%s(%s)
6634 (F) You called a Win32 function with incorrect arguments.
6635 See L<Win32> for more information.
6637 =item $[ used in %s (did you mean $] ?)
6639 (W syntax) You used C<$[> in a comparison, such as:
6645 You probably meant to use C<$]> instead. C<$[> is the base for indexing
6646 arrays. C<$]> is the Perl version number in decimal.
6648 =item Use "%s" instead of "%s"
6650 (F) The second listed construct is no longer legal. Use the first one
6653 =item Useless assignment to a temporary
6655 (W misc) You assigned to an lvalue subroutine, but what
6656 the subroutine returned was a temporary scalar about to
6657 be discarded, so the assignment had no effect.
6659 =item Useless (?-%s) - don't use /%s modifier in regex; marked by
6660 S<<-- HERE> in m/%s/
6662 (W regexp) You have used an internal modifier such as (?-o) that has no
6663 meaning unless removed from the entire regexp:
6665 if ($string =~ /(?-o)$pattern/o) { ... }
6669 if ($string =~ /$pattern/) { ... }
6671 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6672 discovered. See L<perlre>.
6674 =item Useless localization of %s
6676 (W syntax) The localization of lvalues such as C<local($x=10)> is legal,
6677 but in fact the local() currently has no effect. This may change at
6678 some point in the future, but in the meantime such code is discouraged.
6680 =item Useless (?%s) - use /%s modifier in regex; marked by S<<-- HERE> in
6683 (W regexp) You have used an internal modifier such as (?o) that has no
6684 meaning unless applied to the entire regexp:
6686 if ($string =~ /(?o)$pattern/) { ... }
6690 if ($string =~ /$pattern/o) { ... }
6692 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6693 discovered. See L<perlre>.
6695 =item Useless use of attribute "const"
6697 (W misc) The C<const> attribute has no effect except
6698 on anonymous closure prototypes. You applied it to
6699 a subroutine via L<attributes.pm|attributes>. This is only useful
6700 inside an attribute handler for an anonymous subroutine.
6702 =item Useless use of /d modifier in transliteration operator
6704 (W misc) You have used the /d modifier where the searchlist has the
6705 same length as the replacelist. See L<perlop> for more information
6706 about the /d modifier.
6708 =item Useless use of \E
6710 (W misc) You have a \E in a double-quotish string without a C<\U>,
6711 C<\L> or C<\Q> preceding it.
6713 =item Useless use of greediness modifier '%c' in regex; marked by S<<-- HERE> in m/%s/
6715 (W regexp) You specified something like these:
6720 The C<"?"> and C<"+"> don't have any effect, as they modify whether to
6721 match more or fewer when there is a choice, and by specifying to match
6722 exactly a given numer, there is no room left for a choice.
6724 =item Useless use of %s in void context
6726 (W void) You did something without a side effect in a context that does
6727 nothing with the return value, such as a statement that doesn't return a
6728 value from a block, or the left side of a scalar comma operator. Very
6729 often this points not to stupidity on your part, but a failure of Perl
6730 to parse your program the way you thought it would. For example, you'd
6731 get this if you mixed up your C precedence with Python precedence and
6736 when you meant to say
6738 ($one, $two) = (1, 2);
6740 Another common error is to use ordinary parentheses to construct a list
6741 reference when you should be using square or curly brackets, for
6746 when you should have said
6750 The square brackets explicitly turn a list value into a scalar value,
6751 while parentheses do not. So when a parenthesized list is evaluated in
6752 a scalar context, the comma is treated like C's comma operator, which
6753 throws away the left argument, which is not what you want. See
6754 L<perlref> for more on this.
6756 This warning will not be issued for numerical constants equal to 0 or 1
6757 since they are often used in statements like
6759 1 while sub_with_side_effects();
6761 String constants that would normally evaluate to 0 or 1 are warned
6764 =item Useless use of (?-p) in regex; marked by S<<-- HERE> in m/%s/
6766 (W regexp) The C<p> modifier cannot be turned off once set. Trying to do
6769 =item Useless use of "re" pragma
6771 (W) You did C<use re;> without any arguments. That isn't very useful.
6773 =item Useless use of sort in scalar context
6775 (W void) You used sort in scalar context, as in :
6779 This is not very useful, and perl currently optimizes this away.
6781 =item Useless use of %s with no values
6783 (W syntax) You used the push() or unshift() function with no arguments
6784 apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
6785 usually have any effect on the array, so is completely useless. It's
6786 possible in principle that push(@tied_array) could have some effect
6787 if the array is tied to a class which implements a PUSH method. If so,
6788 you can write it as C<push(@tied_array,())> to avoid this warning.
6790 =item "use" not allowed in expression
6792 (F) The "use" keyword is recognized and executed at compile time, and
6793 returns no useful value. See L<perlmod>.
6795 =item Use of assignment to $[ is deprecated
6797 (D deprecated) The C<$[> variable (index of the first element in an array)
6798 is deprecated. See L<perlvar/"$[">.
6800 =item Use of bare << to mean <<"" is deprecated
6802 (D deprecated) You are now encouraged to use the explicitly quoted
6803 form if you wish to use an empty line as the terminator of the
6806 =item Use of /c modifier is meaningless in s///
6808 (W regexp) You used the /c modifier in a substitution. The /c
6809 modifier is not presently meaningful in substitutions.
6811 =item Use of /c modifier is meaningless without /g
6813 (W regexp) You used the /c modifier with a regex operand, but didn't
6814 use the /g modifier. Currently, /c is meaningful only when /g is
6815 used. (This may change in the future.)
6817 =item Use of code point 0x%s is deprecated; the permissible max is 0x%s
6819 (D deprecated) You used a code point that will not be allowed in a
6820 future perl version, because it is too large. Unicode only allows code
6821 points up to 0x10FFFF, but Perl allows much larger ones. However, the
6822 largest possible ones break the perl interpreter in some constructs,
6823 including causing it to hang in a few cases. The known problem areas
6824 are in C<tr///>, regular expression pattern matching using quantifiers,
6825 and as the upper limits in loops.
6827 If your code is to run on various platforms, keep in mind that the upper
6828 limit depends on the platform. It is much larger on 64-bit word sizes
6831 =item Use of comma-less variable list is deprecated
6833 (D deprecated) The values you give to a format should be
6834 separated by commas, not just aligned on a line.
6836 =item Use of each() on hash after insertion without resetting hash iterator results in undefined behavior
6838 (S internal) The behavior of C<each()> after insertion is undefined;
6839 it may skip items, or visit items more than once. Consider using
6840 C<keys()> instead of C<each()>.
6842 =item Use of := for an empty attribute list is not allowed
6844 (F) The construction C<my $x := 42> used to parse as equivalent to
6845 C<my $x : = 42> (applying an empty attribute list to C<$x>).
6846 This construct was deprecated in 5.12.0, and has now been made a syntax
6847 error, so C<:=> can be reclaimed as a new operator in the future.
6849 If you need an empty attribute list, for example in a code generator, add
6850 a space before the C<=>.
6852 =item Use of %s for non-UTF-8 locale is wrong. Assuming a UTF-8 locale
6854 (W locale) You are matching a regular expression using locale rules,
6855 and the specified construct was encountered. This construct is only
6856 valid for UTF-8 locales, which the current locale isn't. This doesn't
6857 make sense. Perl will continue, assuming a Unicode (UTF-8) locale, but
6858 the results are likely to be wrong.
6860 =item Use of freed value in iteration
6862 (F) Perhaps you modified the iterated array within the loop?
6863 This error is typically caused by code like the following:
6866 @a = () for (1,2,@a);
6868 You are not supposed to modify arrays while they are being iterated over.
6869 For speed and efficiency reasons, Perl internally does not do full
6870 reference-counting of iterated items, hence deleting such an item in the
6871 middle of an iteration causes Perl to see a freed value.
6873 =item Use of *glob{FILEHANDLE} is deprecated
6875 (D deprecated) You are now encouraged to use the shorter *glob{IO} form
6876 to access the filehandle slot within a typeglob.
6878 =item Use of /g modifier is meaningless in split
6880 (W regexp) You used the /g modifier on the pattern for a C<split>
6881 operator. Since C<split> always tries to match the pattern
6882 repeatedly, the C</g> has no effect.
6884 =item Use of "goto" to jump into a construct is deprecated
6886 (D deprecated) Using C<goto> to jump from an outer scope into an inner
6887 scope is deprecated and should be avoided.
6889 =item Use of inherited AUTOLOAD for non-method %s() is deprecated
6891 (D deprecated) As an (ahem) accidental feature, C<AUTOLOAD>
6892 subroutines are looked up as methods (using the C<@ISA> hierarchy)
6893 even when the subroutines to be autoloaded were called as plain
6894 functions (e.g. C<Foo::bar()>), not as methods (e.g. C<< Foo->bar() >> or
6895 C<< $obj->bar() >>).
6897 This bug will be rectified in future by using method lookup only for
6898 methods' C<AUTOLOAD>s. However, there is a significant base of existing
6899 code that may be using the old behavior. So, as an interim step, Perl
6900 currently issues an optional warning when non-methods use inherited
6903 The simple rule is: Inheritance will not work when autoloading
6904 non-methods. The simple fix for old code is: In any module that used
6905 to depend on inheriting C<AUTOLOAD> for non-methods from a base class
6906 named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
6909 In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
6910 you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
6911 C<use AutoLoader 'AUTOLOAD';>.
6913 =item Use of %s in printf format not supported
6915 (F) You attempted to use a feature of printf that is accessible from
6916 only C. This usually means there's a better way to do it in Perl.
6918 =item Use of %s is deprecated
6920 (D deprecated) The construct indicated is no longer recommended for use,
6921 generally because there's a better way to do it, and also because the
6922 old way has bad side effects.
6924 =item Use of -l on filehandle%s
6926 (W io) A filehandle represents an opened file, and when you opened the file
6927 it already went past any symlink you are presumably trying to look for.
6928 The operation returned C<undef>. Use a filename instead.
6930 =item Use of %s on a handle without * is deprecated
6932 (D deprecated) You used C<tie>, C<tied> or C<untie> on a scalar but that scalar
6933 happens to hold a typeglob, which means its filehandle will be tied. If
6934 you mean to tie a handle, use an explicit * as in C<tie *$handle>.
6936 This was a long-standing bug that was removed in Perl 5.16, as there was
6937 no way to tie the scalar itself when it held a typeglob, and no way to
6938 untie a scalar that had had a typeglob assigned to it. If you see this
6939 message, you must be using an older version.
6941 =item Use of reference "%s" as array index
6943 (W misc) You tried to use a reference as an array index; this probably
6944 isn't what you mean, because references in numerical context tend
6945 to be huge numbers, and so usually indicates programmer error.
6947 If you really do mean it, explicitly numify your reference, like so:
6948 C<$array[0+$ref]>. This warning is not given for overloaded objects,
6949 however, because you can overload the numification and stringification
6950 operators and then you presumably know what you are doing.
6952 =item Use of state $_ is experimental
6954 (S experimental::lexical_topic) Lexical $_ is an experimental feature and
6955 its behavior may change or even be removed in any future release of perl.
6956 See the explanation under L<perlvar/$_>.
6958 =item Use of strings with code points over 0xFF as arguments to %s
6959 operator is deprecated
6961 (D deprecated) You tried to use one of the string bitwise operators
6962 (C<&> or C<|> or C<^> or C<~>) on a string containing a code point over
6963 0xFF. The string bitwise operators treat their operands as strings of
6964 bytes, and values beyond 0xFF are nonsensical in this context.
6966 =item Use of tainted arguments in %s is deprecated
6968 (W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
6969 arguments and at least one of them is tainted. This used to be allowed
6970 but will become a fatal error in a future version of perl. Untaint your
6971 arguments. See L<perlsec>.
6973 =item Use of uninitialized value%s
6975 (W uninitialized) An undefined value was used as if it were already
6976 defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
6977 To suppress this warning assign a defined value to your variables.
6979 To help you figure out what was undefined, perl will try to tell you
6980 the name of the variable (if any) that was undefined. In some cases
6981 it cannot do this, so it also tells you what operation you used the
6982 undefined value in. Note, however, that perl optimizes your program
6983 and the operation displayed in the warning may not necessarily appear
6984 literally in your program. For example, C<"that $foo"> is usually
6985 optimized into C<"that " . $foo>, and the warning will refer to the
6986 C<concatenation (.)> operator, even though there is no C<.> in
6989 =item "use re 'strict'" is experimental
6991 (S experimental::re_strict) The things that are different when a regular
6992 expression pattern is compiled under C<'strict'> are subject to change
6993 in future Perl releases in incompatible ways. This means that a pattern
6994 that compiles today may not in a future Perl release. This warning is
6995 to alert you to that risk.
6997 =item Use \x{...} for more than two hex characters in regex; marked by
6998 S<<-- HERE> in m/%s/
7000 (F) In a regular expression, you said something like
7004 Perl isn't sure if you meant this
7008 or if you meant this
7010 (?[ [ \x{BE} E F ] ])
7012 You need to add either braces or blanks to disambiguate.
7014 =item Using just the first character returned by \N{} in character class in
7015 regex; marked by S<<-- HERE> in m/%s/
7017 (W regexp) Named Unicode character escapes C<(\N{...})> may return
7018 a multi-character sequence. Even though a character class is
7019 supposed to match just one character of input, perl will match
7020 the whole thing correctly, except when the class is inverted
7021 (C<[^...]>), or the escape is the beginning or final end point of
7022 a range. For these, what should happen isn't clear at all. In
7023 these circumstances, Perl discards all but the first character
7024 of the returned sequence, which is not likely what you want.
7026 =item Using /u for '%s' instead of /%s in regex; marked by S<<-- HERE> in m/%s/
7028 (W regexp) You used a Unicode boundary (C<\b{...}> or C<\B{...}>) in a
7029 portion of a regular expression where the character set modifiers C</a>
7030 or C</aa> are in effect. These two modifiers indicate an ASCII
7031 interpretation, and this doesn't make sense for a Unicode defintion.
7032 The generated regular expression will compile so that the boundary uses
7033 all of Unicode. No other portion of the regular expression is affected.
7035 =item Using !~ with %s doesn't make sense
7037 (F) Using the C<!~> operator with C<s///r>, C<tr///r> or C<y///r> is
7038 currently reserved for future use, as the exact behavior has not
7039 been decided. (Simply returning the boolean opposite of the
7040 modified string is usually not particularly useful.)
7042 =item UTF-16 surrogate U+%X
7044 (S surrogate) You had a UTF-16 surrogate in a context where they are
7045 not considered acceptable. These code points, between U+D800 and
7046 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
7047 internally allows all unsigned integer code points (up to the size limit
7048 available on your platform), including surrogates. But these can cause
7049 problems when being input or output, which is likely where this message
7050 came from. If you really really know what you are doing you can turn
7051 off this warning by C<no warnings 'surrogate';>.
7053 =item Value of %s can be "0"; test with defined()
7055 (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
7056 C<each()>, or C<readdir()> as a boolean value. Each of these constructs
7057 can return a value of "0"; that would make the conditional expression
7058 false, which is probably not what you intended. When using these
7059 constructs in conditional expressions, test their values with the
7060 C<defined> operator.
7062 =item Value of CLI symbol "%s" too long
7064 (W misc) A warning peculiar to VMS. Perl tried to read the value of an
7065 %ENV element from a CLI symbol table, and found a resultant string
7066 longer than 1024 characters. The return value has been truncated to
7069 =item Variable "%s" is not available
7071 (W closure) During compilation, an inner named subroutine or eval is
7072 attempting to capture an outer lexical that is not currently available.
7073 This can happen for one of two reasons. First, the outer lexical may be
7074 declared in an outer anonymous subroutine that has not yet been created.
7075 (Remember that named subs are created at compile time, while anonymous
7076 subs are created at run-time.) For example,
7078 sub { my $a; sub f { $a } }
7080 At the time that f is created, it can't capture the current value of $a,
7081 since the anonymous subroutine hasn't been created yet. Conversely,
7082 the following won't give a warning since the anonymous subroutine has by
7083 now been created and is live:
7085 sub { my $a; eval 'sub f { $a }' }->();
7087 The second situation is caused by an eval accessing a variable that has
7088 gone out of scope, for example,
7096 Here, when the '$a' in the eval is being compiled, f() is not currently
7097 being executed, so its $a is not available for capture.
7099 =item Variable "%s" is not imported%s
7101 (S misc) With "use strict" in effect, you referred to a global variable
7102 that you apparently thought was imported from another module, because
7103 something else of the same name (usually a subroutine) is exported by
7104 that module. It usually means you put the wrong funny character on the
7105 front of your variable.
7107 =item Variable length lookbehind not implemented in regex m/%s/
7109 (F) Lookbehind is allowed only for subexpressions whose length is fixed and
7110 known at compile time. For positive lookbehind, you can use the C<\K>
7111 regex construct as a way to get the equivalent functionality. See
7112 L<perlre/(?<=pattern) \K>.
7114 There are non-obvious Unicode rules under C</i> that can match variably,
7115 but which you might not think could. For example, the substring C<"ss">
7116 can match the single character LATIN SMALL LETTER SHARP S. There are
7117 other sequences of ASCII characters that can match single ligature
7118 characters, such as LATIN SMALL LIGATURE FFI matching C<qr/ffi/i>.
7119 Starting in Perl v5.16, if you only care about ASCII matches, adding the
7120 C</aa> modifier to the regex will exclude all these non-obvious matches,
7121 thus getting rid of this message. You can also say C<S<use re qw(/aa)>>
7122 to apply C</aa> to all regular expressions compiled within its scope.
7125 =item "%s" variable %s masks earlier declaration in same %s
7127 (W misc) A "my", "our" or "state" variable has been redeclared in the
7128 current scope or statement, effectively eliminating all access to the
7129 previous instance. This is almost always a typographical error. Note
7130 that the earlier variable will still exist until the end of the scope
7131 or until all closure references to it are destroyed.
7133 =item Variable syntax
7135 (A) You've accidentally run your script through B<csh> instead
7136 of Perl. Check the #! line, or manually feed your script into
7139 =item Variable "%s" will not stay shared
7141 (W closure) An inner (nested) I<named> subroutine is referencing a
7142 lexical variable defined in an outer named subroutine.
7144 When the inner subroutine is called, it will see the value of
7145 the outer subroutine's variable as it was before and during the *first*
7146 call to the outer subroutine; in this case, after the first call to the
7147 outer subroutine is complete, the inner and outer subroutines will no
7148 longer share a common value for the variable. In other words, the
7149 variable will no longer be shared.
7151 This problem can usually be solved by making the inner subroutine
7152 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
7153 reference variables in outer subroutines are created, they
7154 are automatically rebound to the current values of such variables.
7156 =item vector argument not supported with alpha versions
7158 (S printf) The %vd (s)printf format does not support version objects
7161 =item Verb pattern '%s' has a mandatory argument in regex; marked by
7162 S<<-- HERE> in m/%s/
7164 (F) You used a verb pattern that requires an argument. Supply an
7165 argument or check that you are using the right verb.
7167 =item Verb pattern '%s' may not have an argument in regex; marked by
7168 S<<-- HERE> in m/%s/
7170 (F) You used a verb pattern that is not allowed an argument. Remove the
7171 argument or check that you are using the right verb.
7173 =item Version control conflict marker
7175 (F) The parser found a line starting with C<E<lt><<<<<<>,
7176 C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
7177 version control system to mark conflicts after a failed merge operation.
7179 =item Version number must be a constant number
7181 (P) The attempt to translate a C<use Module n.n LIST> statement into
7182 its equivalent C<BEGIN> block found an internal inconsistency with
7185 =item Version string '%s' contains invalid data; ignoring: '%s'
7187 (W misc) The version string contains invalid characters at the end, which
7190 =item Warning: something's wrong
7192 (W) You passed warn() an empty string (the equivalent of C<warn "">) or
7193 you called it with no args and C<$@> was empty.
7195 =item Warning: unable to close filehandle %s properly
7197 (S) The implicit close() done by an open() got an error indication on
7198 the close(). This usually indicates your file system ran out of disk
7201 =item Warning: unable to close filehandle properly: %s
7203 =item Warning: unable to close filehandle %s properly: %s
7205 (S io) There were errors during the implicit close() done on a filehandle
7206 when its reference count reached zero while it was still open, e.g.:
7209 open my $fh, '>', $file or die "open: '$file': $!\n";
7210 print $fh $data or die "print: $!";
7211 } # implicit close here
7213 Because various errors may only be detected by close() (e.g. buffering could
7214 allow the C<print> in this example to return true even when the disk is full),
7215 it is dangerous to ignore its result. So when it happens implicitly, perl will
7216 signal errors by warning.
7218 B<Prior to version 5.22.0, perl ignored such errors>, so the common idiom shown
7219 above was liable to cause B<silent data loss>.
7221 =item Warning: Use of "%s" without parentheses is ambiguous
7223 (S ambiguous) You wrote a unary operator followed by something that
7224 looks like a binary operator that could also have been interpreted as a
7225 term or unary operator. For instance, if you know that the rand
7226 function has a default argument of 1.0, and you write
7230 you may THINK you wrote the same thing as
7234 but in actual fact, you got
7238 So put in parentheses to say what you really mean.
7240 =item when is experimental
7242 (S experimental::smartmatch) C<when> depends on smartmatch, which is
7243 experimental. Additionally, it has several special cases that may
7244 not be immediately obvious, and their behavior may change or
7245 even be removed in any future release of perl. See the explanation
7246 under L<perlsyn/Experimental Details on given and when>.
7248 =item Wide character in %s
7250 (S utf8) Perl met a wide character (>255) when it wasn't expecting
7251 one. This warning is by default on for I/O (like print). The easiest
7252 way to quiet this warning is simply to add the C<:utf8> layer to the
7253 output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
7254 warning is to add C<no warnings 'utf8';> but that is often closer to
7255 cheating. In general, you are supposed to explicitly mark the
7256 filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
7258 =item Wide character (U+%X) in %s
7260 (W locale) While in a single-byte locale (I<i.e.>, a non-UTF-8
7261 one), a multi-byte character was encountered. Perl considers this
7262 character to be the specified Unicode code point. Combining non-UTF-8
7263 locales and Unicode is dangerous. Almost certainly some characters
7264 will have two different representations. For example, in the ISO 8859-7
7265 (Greek) locale, the code point 0xC3 represents a Capital Gamma. But so
7266 also does 0x393. This will make string comparisons unreliable.
7268 You likely need to figure out how this multi-byte character got mixed up
7269 with your single-byte locale (or perhaps you thought you had a UTF-8
7270 locale, but Perl disagrees).
7272 =item Within []-length '%c' not allowed
7274 (F) The count in the (un)pack template may be replaced by C<[TEMPLATE]>
7275 only if C<TEMPLATE> always matches the same amount of packed bytes that
7276 can be determined from the template alone. This is not possible if
7277 it contains any of the codes @, /, U, u, w or a *-length. Redesign
7280 =item %s() with negative argument
7282 (S misc) Certain operations make no sense with negative arguments.
7283 Warning is given and the operation is not done.
7285 =item write() on closed filehandle %s
7287 (W closed) The filehandle you're writing to got itself closed sometime
7288 before now. Check your control flow.
7290 =item %s "\x%X" does not map to Unicode
7292 (S utf8) When reading in different encodings, Perl tries to
7293 map everything into Unicode characters. The bytes you read
7294 in are not legal in this encoding. For example
7296 utf8 "\xE4" does not map to Unicode
7298 if you try to read in the a-diaereses Latin-1 as UTF-8.
7300 =item 'X' outside of string
7302 (F) You had a (un)pack template that specified a relative position before
7303 the beginning of the string being (un)packed. See L<perlfunc/pack>.
7305 =item 'x' outside of string in unpack
7307 (F) You had a pack template that specified a relative position after
7308 the end of the string being unpacked. See L<perlfunc/pack>.
7310 =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
7312 (F) And you probably never will, because you probably don't have the
7313 sources to your kernel, and your vendor probably doesn't give a rip
7314 about what you want. Your best bet is to put a setuid C wrapper around
7317 =item You need to quote "%s"
7319 (W syntax) You assigned a bareword as a signal handler name.
7320 Unfortunately, you already have a subroutine of that name declared,
7321 which means that Perl 5 will try to call the subroutine when the
7322 assignment is executed, which is probably not what you want. (If it IS
7323 what you want, put an & in front.)
7325 =item Your random numbers are not that random
7327 (F) When trying to initialize the random seed for hashes, Perl could
7328 not get any randomness out of your system. This usually indicates
7329 Something Very Wrong.
7331 =item Zero length \N{} in regex; marked by S<<-- HERE> in m/%s/
7333 (F) Named Unicode character escapes (C<\N{...}>) may return a zero-length
7334 sequence. Such an escape was used in an extended character class, i.e.
7335 C<(?[...])>, or under C<use re 'strict'>, which is not permitted. Check
7336 that the correct escape has been used, and the correct charnames handler
7337 is in scope. The S<<-- HERE> shows whereabouts in the regular
7338 expression the problem was discovered.
7344 L<warnings>, L<diagnostics>.