3 perldiag - various Perl diagnostics
7 These messages are classified as follows (listed in increasing order of
10 (W) A warning (optional).
11 (D) A deprecation (enabled by default).
12 (S) A severe warning (enabled by default).
13 (F) A fatal error (trappable).
14 (P) An internal error you should never see (trappable).
15 (X) A very fatal error (nontrappable).
16 (A) An alien error message (not generated by Perl).
18 The majority of messages from the first three classifications above
19 (W, D & S) can be controlled using the C<warnings> pragma.
21 If a message can be controlled by the C<warnings> pragma, its warning
22 category is included with the classification letter in the description
23 below. E.g. C<(W closed)> means a warning in the C<closed> category.
25 Optional warnings are enabled by using the C<warnings> pragma or the B<-w>
26 and B<-W> switches. Warnings may be captured by setting C<$SIG{__WARN__}>
27 to a reference to a routine that will be called on each warning instead
28 of printing it. See L<perlvar>.
30 Severe warnings are always enabled, unless they are explicitly disabled
31 with the C<warnings> pragma or the B<-X> switch.
33 Trappable errors may be trapped using the eval operator. See
34 L<perlfunc/eval>. In almost all cases, warnings may be selectively
35 disabled or promoted to fatal errors using the C<warnings> pragma.
38 The messages are in alphabetical order, without regard to upper or
39 lower-case. Some of these messages are generic. Spots that vary are
40 denoted with a %s or other printf-style escape. These escapes are
41 ignored by the alphabetical order, as are all characters other than
42 letters. To look up your message, just ignore anything that is not a
47 =item accept() on closed socket %s
49 (W closed) You tried to do an accept on a closed socket. Did you forget
50 to check the return value of your socket() call? See
53 =item Aliasing via reference is experimental
55 (S experimental::refaliasing) This warning is emitted if you use
56 a reference constructor on the left-hand side of an assignment to
57 alias one variable to another. Simply suppress the warning if you
58 want to use the feature, but know that in doing so you are taking
59 the risk of using an experimental feature which may change or be
60 removed in a future Perl version:
62 no warnings "experimental::refaliasing";
63 use feature "refaliasing";
66 =item Allocation too large: %x
68 (X) You can't allocate more than 64K on an MS-DOS machine.
70 =item '%c' allowed only after types %s in %s
72 (F) The modifiers '!', '<' and '>' are allowed in pack() or unpack() only
73 after certain types. See L<perlfunc/pack>.
75 =item Ambiguous call resolved as CORE::%s(), qualify as such or use &
77 (W ambiguous) A subroutine you have declared has the same name as a Perl
78 keyword, and you have used the name without qualification for calling
79 one or the other. Perl decided to call the builtin because the
80 subroutine is not imported.
82 To force interpretation as a subroutine call, either put an ampersand
83 before the subroutine name, or qualify the name with its package.
84 Alternatively, you can import the subroutine (or pretend that it's
85 imported with the C<use subs> pragma).
87 To silently interpret it as the Perl operator, use the C<CORE::> prefix
88 on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
89 to be an object method (see L<perlsub/"Subroutine Attributes"> or
92 =item Ambiguous range in transliteration operator
94 (F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
95 all. To include a C<-> character in a transliteration, put it either
96 first or last. (In the past, C<tr/a-z-0//> was synonymous with
97 C<tr/a-y//>, which was probably not what you would have expected.)
99 =item Ambiguous use of %s resolved as %s
101 (S ambiguous) You said something that may not be interpreted the way
102 you thought. Normally it's pretty easy to disambiguate it by supplying
103 a missing quote, operator, parenthesis pair or declaration.
105 =item Ambiguous use of -%s resolved as -&%s()
107 (S ambiguous) You wrote something like C<-foo>, which might be the
108 string C<"-foo">, or a call to the function C<foo>, negated. If you meant
109 the string, just write C<"-foo">. If you meant the function call,
112 =item Ambiguous use of %c resolved as operator %c
114 (S ambiguous) C<%>, C<&>, and C<*> are both infix operators (modulus,
115 bitwise and, and multiplication) I<and> initial special characters
116 (denoting hashes, subroutines and typeglobs), and you said something
117 like C<*foo * foo> that might be interpreted as either of them. We
118 assumed you meant the infix operator, but please try to make it more
119 clear -- in the example given, you might write C<*foo * foo()> if you
120 really meant to multiply a glob by the result of calling a function.
122 =item Ambiguous use of %c{%s} resolved to %c%s
124 (W ambiguous) You wrote something like C<@{foo}>, which might be
125 asking for the variable C<@foo>, or it might be calling a function
126 named foo, and dereferencing it as an array reference. If you wanted
127 the variable, you can just write C<@foo>. If you wanted to call the
128 function, write C<@{foo()}> ... or you could just not have a variable
129 and a function with the same name, and save yourself a lot of trouble.
131 =item Ambiguous use of %c{%s[...]} resolved to %c%s[...]
133 =item Ambiguous use of %c{%s{...}} resolved to %c%s{...}
135 (W ambiguous) You wrote something like C<${foo[2]}> (where foo represents
136 the name of a Perl keyword), which might be looking for element number
137 2 of the array named C<@foo>, in which case please write C<$foo[2]>, or you
138 might have meant to pass an anonymous arrayref to the function named
139 foo, and then do a scalar deref on the value it returns. If you meant
140 that, write C<${foo([2])}>.
142 In regular expressions, the C<${foo[2]}> syntax is sometimes necessary
143 to disambiguate between array subscripts and character classes.
144 C</$length[2345]/>, for instance, will be interpreted as C<$length> followed
145 by the character class C<[2345]>. If an array subscript is what you
146 want, you can avoid the warning by changing C</${length[2345]}/> to the
147 unsightly C</${\$length[2345]}/>, by renaming your array to something
148 that does not coincide with a built-in keyword, or by simply turning
149 off warnings with C<no warnings 'ambiguous';>.
151 =item '|' and '<' may not both be specified on command line
153 (F) An error peculiar to VMS. Perl does its own command line
154 redirection, and found that STDIN was a pipe, and that you also tried to
155 redirect STDIN using '<'. Only one STDIN stream to a customer, please.
157 =item '|' and '>' may not both be specified on command line
159 (F) An error peculiar to VMS. Perl does its own command line
160 redirection, and thinks you tried to redirect stdout both to a file and
161 into a pipe to another command. You need to choose one or the other,
162 though nothing's stopping you from piping into a program or Perl script
163 which 'splits' output into two streams, such as
165 open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
172 =item Applying %s to %s will act on scalar(%s)
174 (W misc) The pattern match (C<//>), substitution (C<s///>), and
175 transliteration (C<tr///>) operators work on scalar values. If you apply
176 one of them to an array or a hash, it will convert the array or hash to
177 a scalar value (the length of an array, or the population info of a
178 hash) and then work on that scalar value. This is probably not what
179 you meant to do. See L<perlfunc/grep> and L<perlfunc/map> for
182 =item Arg too short for msgsnd
184 (F) msgsnd() requires a string at least as long as sizeof(long).
186 =item Argument "%s" isn't numeric%s
188 (W numeric) The indicated string was fed as an argument to an operator
189 that expected a numeric value instead. If you're fortunate the message
190 will identify which operator was so unfortunate.
192 Note that for the C<Inf> and C<NaN> (infinity and not-a-number) the
193 definition of "numeric" is somewhat unusual: the strings themselves
194 (like "Inf") are considered numeric, and anything following them is
195 considered non-numeric.
197 =item Argument list not closed for PerlIO layer "%s"
199 (W layer) When pushing a layer with arguments onto the Perl I/O
200 system you forgot the ) that closes the argument list. (Layers
201 take care of transforming data between external and internal
202 representations.) Perl stopped parsing the layer list at this
203 point and did not attempt to push this layer. If your program
204 didn't explicitly request the failing operation, it may be the
205 result of the value of the environment variable PERLIO.
207 =item Argument "%s" treated as 0 in increment (++)
209 (W numeric) The indicated string was fed as an argument to the C<++>
210 operator which expects either a number or a string matching
211 C</^[a-zA-Z]*[0-9]*\z/>. See L<perlop/Auto-increment and
212 Auto-decrement> for details.
214 =item assertion botched: %s
216 (X) The malloc package that comes with Perl had an internal failure.
218 =item Assertion %s failed: file "%s", line %d
220 (X) A general assertion failed. The file in question must be examined.
222 =item Assigned value is not a reference
224 (F) You tried to assign something that was not a reference to an lvalue
225 reference (e.g., C<\$x = $y>). If you meant to make $x an alias to $y, use
228 =item Assigned value is not %s reference
230 (F) You tried to assign a reference to a reference constructor, but the
231 two references were not of the same type. You cannot alias a scalar to
232 an array, or an array to a hash; the two types must match.
237 \$x = $y; # error; did you mean \$y?
239 =item Assigning non-zero to $[ is no longer possible
241 (F) When the "array_base" feature is disabled (e.g., under C<use v5.16;>)
242 the special variable C<$[>, which is deprecated, is now a fixed zero value.
244 =item Assignment to both a list and a scalar
246 (F) If you assign to a conditional operator, the 2nd and 3rd arguments
247 must either both be scalars or both be lists. Otherwise Perl won't
248 know which context to supply to the right side.
250 =item <> at require-statement should be quotes
252 (F) You wrote C<< require <file> >> when you should have written
255 =item Attempt to access disallowed key '%s' in a restricted hash
257 (F) The failing code has attempted to get or set a key which is not in
258 the current set of allowed keys of a restricted hash.
260 =item Attempt to bless into a freed package
262 (F) You wrote C<bless $foo> with one argument after somehow causing
263 the current package to be freed. Perl cannot figure out what to
264 do, so it throws up in hands in despair.
266 =item Attempt to bless into a reference
268 (F) The CLASSNAME argument to the bless() operator is expected to be
269 the name of the package to bless the resulting object into. You've
270 supplied instead a reference to something: perhaps you wrote
276 bless $self, ref($proto) || $proto;
278 If you actually want to bless into the stringified version
279 of the reference supplied, you need to stringify it yourself, for
282 bless $self, "$proto";
284 =item Attempt to clear deleted array
286 (S debugging) An array was assigned to when it was being freed.
287 Freed values are not supposed to be visible to Perl code. This
288 can also happen if XS code calls C<av_clear> from a custom magic
289 callback on the array.
291 =item Attempt to delete disallowed key '%s' from a restricted hash
293 (F) The failing code attempted to delete from a restricted hash a key
294 which is not in its key set.
296 =item Attempt to delete readonly key '%s' from a restricted hash
298 (F) The failing code attempted to delete a key whose value has been
299 declared readonly from a restricted hash.
301 =item Attempt to free non-arena SV: 0x%x
303 (S internal) All SV objects are supposed to be allocated from arenas
304 that will be garbage collected on exit. An SV was discovered to be
305 outside any of those arenas.
307 =item Attempt to free nonexistent shared string '%s'%s
309 (S internal) Perl maintains a reference-counted internal table of
310 strings to optimize the storage and access of hash keys and other
311 strings. This indicates someone tried to decrement the reference count
312 of a string that can no longer be found in the table.
314 =item Attempt to free temp prematurely: SV 0x%x
316 (S debugging) Mortalized values are supposed to be freed by the
317 free_tmps() routine. This indicates that something else is freeing the
318 SV before the free_tmps() routine gets a chance, which means that the
319 free_tmps() routine will be freeing an unreferenced scalar when it does
322 =item Attempt to free unreferenced glob pointers
324 (S internal) The reference counts got screwed up on symbol aliases.
326 =item Attempt to free unreferenced scalar: SV 0x%x
328 (S internal) Perl went to decrement the reference count of a scalar to
329 see if it would go to 0, and discovered that it had already gone to 0
330 earlier, and should have been freed, and in fact, probably was freed.
331 This could indicate that SvREFCNT_dec() was called too many times, or
332 that SvREFCNT_inc() was called too few times, or that the SV was
333 mortalized when it shouldn't have been, or that memory has been
336 =item Attempt to pack pointer to temporary value
338 (W pack) You tried to pass a temporary value (like the result of a
339 function, or a computed expression) to the "p" pack() template. This
340 means the result contains a pointer to a location that could become
341 invalid anytime, even before the end of the current statement. Use
342 literals or global values as arguments to the "p" pack() template to
345 =item Attempt to reload %s aborted.
347 (F) You tried to load a file with C<use> or C<require> that failed to
348 compile once already. Perl will not try to compile this file again
349 unless you delete its entry from %INC. See L<perlfunc/require> and
352 =item Attempt to set length of freed array
354 (W misc) You tried to set the length of an array which has
355 been freed. You can do this by storing a reference to the
356 scalar representing the last index of an array and later
357 assigning through that reference. For example
359 $r = do {my @a; \$#a};
362 =item Attempt to use reference as lvalue in substr
364 (W substr) You supplied a reference as the first argument to substr()
365 used as an lvalue, which is pretty strange. Perhaps you forgot to
366 dereference it first. See L<perlfunc/substr>.
368 =item Attribute "locked" is deprecated
370 (D deprecated) You have used the attributes pragma to modify the
371 "locked" attribute on a code reference. The :locked attribute is
372 obsolete, has had no effect since 5005 threads were removed, and
373 will be removed in a future release of Perl 5.
375 =item Attribute prototype(%s) discards earlier prototype attribute in same sub
377 (W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for
378 example. Since each sub can only have one prototype, the earlier
379 declaration(s) are discarded while the last one is applied.
381 =item Attribute "unique" is deprecated
383 (D deprecated) You have used the attributes pragma to modify
384 the "unique" attribute on an array, hash or scalar reference.
385 The :unique attribute has had no effect since Perl 5.8.8, and
386 will be removed in a future release of Perl 5.
388 =item av_reify called on tied array
390 (S debugging) This indicates that something went wrong and Perl got I<very>
391 confused about C<@_> or C<@DB::args> being tied.
393 =item Bad arg length for %s, is %u, should be %d
395 (F) You passed a buffer of the wrong size to one of msgctl(), semctl()
396 or shmctl(). In C parlance, the correct sizes are, respectively,
397 S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
398 S<sizeof(struct shmid_ds *)>.
400 =item Bad evalled substitution pattern
402 (F) You've used the C</e> switch to evaluate the replacement for a
403 substitution, but perl found a syntax error in the code to evaluate,
404 most likely an unexpected right brace '}'.
406 =item Bad filehandle: %s
408 (F) A symbol was passed to something wanting a filehandle, but the
409 symbol has no filehandle associated with it. Perhaps you didn't do an
410 open(), or did it in another package.
412 =item Bad free() ignored
414 (S malloc) An internal routine called free() on something that had never
415 been malloc()ed in the first place. Mandatory, but can be disabled by
416 setting environment variable C<PERL_BADFREE> to 0.
418 This message can be seen quite often with DB_File on systems with "hard"
419 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
420 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
424 (P) One of the internal hash routines was passed a null HV pointer.
426 =item Badly placed ()'s
428 (A) You've accidentally run your script through B<csh> instead
429 of Perl. Check the #! line, or manually feed your script into
432 =item Bad name after %s
434 (F) You started to name a symbol by using a package prefix, and then
435 didn't finish the symbol. In particular, you can't interpolate outside
444 $sym = "mypack::$var";
446 =item Bad plugin affecting keyword '%s'
448 (F) An extension using the keyword plugin mechanism violated the
451 =item Bad realloc() ignored
453 (S malloc) An internal routine called realloc() on something that
454 had never been malloc()ed in the first place. Mandatory, but can
455 be disabled by setting the environment variable C<PERL_BADFREE> to 1.
457 =item Bad symbol for array
459 (P) An internal request asked to add an array entry to something that
460 wasn't a symbol table entry.
462 =item Bad symbol for dirhandle
464 (P) An internal request asked to add a dirhandle entry to something
465 that wasn't a symbol table entry.
467 =item Bad symbol for filehandle
469 (P) An internal request asked to add a filehandle entry to something
470 that wasn't a symbol table entry.
472 =item Bad symbol for hash
474 (P) An internal request asked to add a hash entry to something that
475 wasn't a symbol table entry.
477 =item Bad symbol for scalar
479 (P) An internal request asked to add a scalar entry to something that
480 wasn't a symbol table entry.
482 =item Bareword found in conditional
484 (W bareword) The compiler found a bareword where it expected a
485 conditional, which often indicates that an || or && was parsed as part
486 of the last argument of the previous construct, for example:
490 It may also indicate a misspelled constant that has been interpreted as
493 use constant TYPO => 1;
494 if (TYOP) { print "foo" }
496 The C<strict> pragma is useful in avoiding such errors.
498 =item Bareword "%s" not allowed while "strict subs" in use
500 (F) With "strict subs" in use, a bareword is only allowed as a
501 subroutine identifier, in curly brackets or to the left of the "=>"
502 symbol. Perhaps you need to predeclare a subroutine?
504 =item Bareword "%s" refers to nonexistent package
506 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
507 compiler saw no other uses of that namespace before that point. Perhaps
508 you need to predeclare a package?
510 =item BEGIN failed--compilation aborted
512 (F) An untrapped exception was raised while executing a BEGIN
513 subroutine. Compilation stops immediately and the interpreter is
516 =item BEGIN not safe after errors--compilation aborted
518 (F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
519 implies a C<BEGIN {}>) after one or more compilation errors had already
520 occurred. Since the intended environment for the C<BEGIN {}> could not
521 be guaranteed (due to the errors), and since subsequent code likely
522 depends on its correct operation, Perl just gave up.
524 =item \%d better written as $%d
526 (W syntax) Outside of patterns, backreferences live on as variables.
527 The use of backslashes is grandfathered on the right-hand side of a
528 substitution, but stylistically it's better to use the variable form
529 because other Perl programmers will expect it, and it works better if
530 there are more than 9 backreferences.
532 =item Binary number > 0b11111111111111111111111111111111 non-portable
534 (W portable) The binary number you specified is larger than 2**32-1
535 (4294967295) and therefore non-portable between systems. See
536 L<perlport> for more on portability concerns.
538 =item bind() on closed socket %s
540 (W closed) You tried to do a bind on a closed socket. Did you forget to
541 check the return value of your socket() call? See L<perlfunc/bind>.
543 =item binmode() on closed filehandle %s
545 (W unopened) You tried binmode() on a filehandle that was never opened.
546 Check your control flow and number of arguments.
548 =item Bit vector size > 32 non-portable
550 (W portable) Using bit vector sizes larger than 32 is non-portable.
552 =item Bizarre copy of %s
554 (P) Perl detected an attempt to copy an internal value that is not
557 =item Bizarre SvTYPE [%d]
559 (P) When starting a new thread or returning values from a thread, Perl
560 encountered an invalid data type.
562 =item Both or neither range ends should be Unicode in regex; marked by
565 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
567 In a bracketed character class in a regular expression pattern, you
568 had a range which has exactly one end of it specified using C<\N{}>, and
569 the other end is specified using a non-portable mechanism. Perl treats
570 the range as a Unicode range, that is, all the characters in it are
571 considered to be the Unicode characters, and which may be different code
572 points on some platforms Perl runs on. For example, C<[\N{U+06}-\x08]>
573 is treated as if you had instead said C<[\N{U+06}-\N{U+08}]>, that is it
574 matches the characters whose code points in Unicode are 6, 7, and 8.
575 But that C<\x08> might indicate that you meant something different, so
576 the warning gets raised.
578 =item Buffer overflow in prime_env_iter: %s
580 (W internal) A warning peculiar to VMS. While Perl was preparing to
581 iterate over %ENV, it encountered a logical name or symbol definition
582 which was too long, so it was truncated to the string shown.
584 =item Callback called exit
586 (F) A subroutine invoked from an external package via call_sv()
587 exited by calling exit.
589 =item %s() called too early to check prototype
591 (W prototype) You've called a function that has a prototype before the
592 parser saw a definition or declaration for it, and Perl could not check
593 that the call conforms to the prototype. You need to either add an
594 early prototype declaration for the subroutine in question, or move the
595 subroutine definition ahead of the call to get proper prototype
596 checking. Alternatively, if you are certain that you're calling the
597 function correctly, you may put an ampersand before the name to avoid
598 the warning. See L<perlsub>.
600 =item Calling POSIX::%s() is deprecated
602 (D deprecated) You called a function whose use is deprecated. See
603 the function's name in L<POSIX> for details.
607 (F) You passed an invalid number (like an infinity or not-a-number) to C<chr>.
609 =item Cannot compress %f in pack
611 (F) You tried compressing an infinity or not-a-number as an unsigned
612 integer with BER, which makes no sense.
614 =item Cannot compress integer in pack
616 (F) An argument to pack("w",...) was too large to compress.
617 The BER compressed integer format can only be used with positive
618 integers, and you attempted to compress a very large number (> 1e308).
619 See L<perlfunc/pack>.
621 =item Cannot compress negative numbers in pack
623 (F) An argument to pack("w",...) was negative. The BER compressed integer
624 format can only be used with positive integers. See L<perlfunc/pack>.
626 =item Cannot convert a reference to %s to typeglob
628 (F) You manipulated Perl's symbol table directly, stored a reference
629 in it, then tried to access that symbol via conventional Perl syntax.
630 The access triggers Perl to autovivify that typeglob, but it there is
631 no legal conversion from that type of reference to a typeglob.
633 =item Cannot copy to %s
635 (P) Perl detected an attempt to copy a value to an internal type that cannot
636 be directly assigned to.
638 =item Cannot find encoding "%s"
640 (S io) You tried to apply an encoding that did not exist to a filehandle,
641 either with open() or binmode().
643 =item Cannot pack %f with '%c'
645 (F) You tried converting an infinity or not-a-number to an integer,
646 which makes no sense.
648 =item Cannot printf %f with '%c'
650 (F) You tried printing an infinity or not-a-number as a character (%c),
651 which makes no sense. Maybe you meant '%s', or just stringifying it?
653 =item Cannot set tied @DB::args
655 (F) C<caller> tried to set C<@DB::args>, but found it tied. Tying C<@DB::args>
656 is not supported. (Before this error was added, it used to crash.)
658 =item Cannot tie unreifiable array
660 (P) You somehow managed to call C<tie> on an array that does not
661 keep a reference count on its arguments and cannot be made to
662 do so. Such arrays are not even supposed to be accessible to
663 Perl code, but are only used internally.
665 =item Cannot yet reorder sv_catpvfn() arguments from va_list
667 (F) Some XS code tried to use C<sv_catpvfn()> or a related function with a
668 format string that specifies explicit indexes for some of the elements, and
669 using a C-style variable-argument list (a C<va_list>). This is not currently
670 supported. XS authors wanting to do this must instead construct a C array of
671 C<SV*> scalars containing the arguments.
673 =item Can only compress unsigned integers in pack
675 (F) An argument to pack("w",...) was not an integer. The BER compressed
676 integer format can only be used with positive integers, and you attempted
677 to compress something else. See L<perlfunc/pack>.
679 =item Can't bless non-reference value
681 (F) Only hard references may be blessed. This is how Perl "enforces"
682 encapsulation of objects. See L<perlobj>.
684 =item Can't "break" in a loop topicalizer
686 (F) You called C<break>, but you're in a C<foreach> block rather than
687 a C<given> block. You probably meant to use C<next> or C<last>.
689 =item Can't "break" outside a given block
691 (F) You called C<break>, but you're not inside a C<given> block.
693 =item Can't call method "%s" on an undefined value
695 (F) You used the syntax of a method call, but the slot filled by the
696 object reference or package name contains an undefined value. Something
697 like this will reproduce the error:
700 process $BADREF 1,2,3;
701 $BADREF->process(1,2,3);
703 =item Can't call method "%s" on unblessed reference
705 (F) A method call must know in what package it's supposed to run. It
706 ordinarily finds this out from the object reference you supply, but you
707 didn't supply an object reference in this case. A reference isn't an
708 object reference until it has been blessed. See L<perlobj>.
710 =item Can't call method "%s" without a package or object reference
712 (F) You used the syntax of a method call, but the slot filled by the
713 object reference or package name contains an expression that returns a
714 defined value which is neither an object reference nor a package name.
715 Something like this will reproduce the error:
718 process $BADREF 1,2,3;
719 $BADREF->process(1,2,3);
721 =item Can't call mro_isa_changed_in() on anonymous symbol table
723 (P) Perl got confused as to whether a hash was a plain hash or a
724 symbol table hash when trying to update @ISA caches.
726 =item Can't call mro_method_changed_in() on anonymous symbol table
728 (F) An XS module tried to call C<mro_method_changed_in> on a hash that was
729 not attached to the symbol table.
731 =item Can't chdir to %s
733 (F) You called C<perl -x/foo/bar>, but F</foo/bar> is not a directory
734 that you can chdir to, possibly because it doesn't exist.
736 =item Can't check filesystem of script "%s" for nosuid
738 (P) For some reason you can't check the filesystem of the script for
741 =item Can't coerce %s to %s in %s
743 (F) Certain types of SVs, in particular real symbol table entries
744 (typeglobs), can't be forced to stop being what they are. So you can't
754 but then $foo no longer contains a glob.
756 =item Can't "continue" outside a when block
758 (F) You called C<continue>, but you're not inside a C<when>
761 =item Can't create pipe mailbox
763 (P) An error peculiar to VMS. The process is suffering from exhausted
764 quotas or other plumbing problems.
766 =item Can't declare %s in "%s"
768 (F) Only scalar, array, and hash variables may be declared as "my", "our" or
769 "state" variables. They must have ordinary identifiers as names.
771 =item Can't "default" outside a topicalizer
773 (F) You have used a C<default> block that is neither inside a
774 C<foreach> loop nor a C<given> block. (Note that this error is
775 issued on exit from the C<default> block, so you won't get the
776 error if you use an explicit C<continue>.)
778 =item Can't do inplace edit: %s is not a regular file
780 (S inplace) You tried to use the B<-i> switch on a special file, such as
781 a file in /dev, a FIFO or an uneditable directory. The file was ignored.
783 =item Can't do inplace edit on %s: %s
785 (S inplace) The creation of the new file failed for the indicated
788 =item Can't do inplace edit without backup
790 (F) You're on a system such as MS-DOS that gets confused if you try
791 reading from a deleted (but still opened) file. You have to say
792 C<-i.bak>, or some such.
794 =item Can't do inplace edit: %s would not be unique
796 (S inplace) Your filesystem does not support filenames longer than 14
797 characters and Perl was unable to create a unique filename during
798 inplace editing with the B<-i> switch. The file was ignored.
800 =item Can't do %s("%s") on non-UTF-8 locale; resolved to "%s".
802 (W locale) You are 1) running under "C<use locale>"; 2) the current
803 locale is not a UTF-8 one; 3) you tried to do the designated case-change
804 operation on the specified Unicode character; and 4) the result of this
805 operation would mix Unicode and locale rules, which likely conflict.
806 Mixing of different rule types is forbidden, so the operation was not
807 done; instead the result is the indicated value, which is the best
808 available that uses entirely Unicode rules. That turns out to almost
809 always be the original character, unchanged.
811 It is generally a bad idea to mix non-UTF-8 locales and Unicode, and
812 this issue is one of the reasons why. This warning is raised when
813 Unicode rules would normally cause the result of this operation to
814 contain a character that is in the range specified by the locale,
815 0..255, and hence is subject to the locale's rules, not Unicode's.
817 If you are using locale purely for its characteristics related to things
818 like its numeric and time formatting (and not C<LC_CTYPE>), consider
819 using a restricted form of the locale pragma (see L<perllocale/The "use
820 locale" pragma>) like "S<C<use locale ':not_characters'>>".
822 Note that failed case-changing operations done as a result of
823 case-insensitive C</i> regular expression matching will show up in this
824 warning as having the C<fc> operation (as that is what the regular
825 expression engine calls behind the scenes.)
827 =item Can't do waitpid with flags
829 (F) This machine doesn't have either waitpid() or wait4(), so only
830 waitpid() without flags is emulated.
832 =item Can't emulate -%s on #! line
834 (F) The #! line specifies a switch that doesn't make sense at this
835 point. For example, it'd be kind of silly to put a B<-x> on the #!
838 =item Can't %s %s-endian %ss on this platform
840 (F) Your platform's byte-order is neither big-endian nor little-endian,
841 or it has a very strange pointer size. Packing and unpacking big- or
842 little-endian floating point values and pointers may not be possible.
843 See L<perlfunc/pack>.
845 =item Can't exec "%s": %s
847 (W exec) A system(), exec(), or piped open call could not execute the
848 named program for the indicated reason. Typical reasons include: the
849 permissions were wrong on the file, the file wasn't found in
850 C<$ENV{PATH}>, the executable in question was compiled for another
851 architecture, or the #! line in a script points to an interpreter that
852 can't be run for similar reasons. (Or maybe your system doesn't support
857 (F) Perl was trying to execute the indicated program for you because
858 that's what the #! line said. If that's not what you wanted, you may
859 need to mention "perl" on the #! line somewhere.
861 =item Can't execute %s
863 (F) You used the B<-S> switch, but the copies of the script to execute
864 found in the PATH did not have correct permissions.
866 =item Can't find an opnumber for "%s"
868 (F) A string of a form C<CORE::word> was given to prototype(), but there
869 is no builtin with the name C<word>.
871 =item Can't find label %s
873 (F) You said to goto a label that isn't mentioned anywhere that it's
874 possible for us to go to. See L<perlfunc/goto>.
876 =item Can't find %s on PATH
878 (F) You used the B<-S> switch, but the script to execute could not be
881 =item Can't find %s on PATH, '.' not in PATH
883 (F) You used the B<-S> switch, but the script to execute could not be
884 found in the PATH, or at least not with the correct permissions. The
885 script exists in the current directory, but PATH prohibits running it.
887 =item Can't find string terminator %s anywhere before EOF
889 (F) Perl strings can stretch over multiple lines. This message means
890 that the closing delimiter was omitted. Because bracketed quotes count
891 nesting levels, the following is missing its final parenthesis:
893 print q(The character '(' starts a side comment.);
895 If you're getting this error from a here-document, you may have
896 included unseen whitespace before or after your closing tag or there
897 may not be a linebreak after it. A good programmer's editor will have
898 a way to help you find these characters (or lack of characters). See
899 L<perlop> for the full details on here-documents.
901 =item Can't find Unicode property definition "%s"
903 =item Can't find Unicode property definition "%s" in regex; marked by <-- HERE in m/%s/
905 (F) The named property which you specified via C<\p> or C<\P> is not one
906 known to Perl. Perhaps you misspelled the name? See
907 L<perluniprops/Properties accessible through \p{} and \P{}>
908 for a complete list of available official
909 properties. If it is a
910 L<user-defined property|perlunicode/User-Defined Character Properties>
911 it must have been defined by the time the regular expression is
914 If you didn't mean to use a Unicode property, escape the C<\p>, either
915 by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, or
920 (F) A fatal error occurred while trying to fork while opening a
923 =item Can't fork, trying again in 5 seconds
925 (W pipe) A fork in a piped open failed with EAGAIN and will be retried
928 =item Can't get filespec - stale stat buffer?
930 (S) A warning peculiar to VMS. This arises because of the difference
931 between access checks under VMS and under the Unix model Perl assumes.
932 Under VMS, access checks are done by filename, rather than by bits in
933 the stat buffer, so that ACLs and other protections can be taken into
934 account. Unfortunately, Perl assumes that the stat buffer contains all
935 the necessary information, and passes it, instead of the filespec, to
936 the access-checking routine. It will try to retrieve the filespec using
937 the device name and FID present in the stat buffer, but this works only
938 if you haven't made a subsequent call to the CRTL stat() routine,
939 because the device name is overwritten with each call. If this warning
940 appears, the name lookup failed, and the access-checking routine gave up
941 and returned FALSE, just to be conservative. (Note: The access-checking
942 routine knows about the Perl C<stat> operator and file tests, so you
943 shouldn't ever see this warning in response to a Perl command; it arises
944 only if some internal code takes stat buffers lightly.)
946 =item Can't get pipe mailbox device name
948 (P) An error peculiar to VMS. After creating a mailbox to act as a
949 pipe, Perl can't retrieve its name for later use.
951 =item Can't get SYSGEN parameter value for MAXBUF
953 (P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
954 mailbox buffers to be, and didn't get an answer.
956 =item Can't "goto" into the middle of a foreach loop
958 (F) A "goto" statement was executed to jump into the middle of a foreach
959 loop. You can't get there from here. See L<perlfunc/goto>.
961 =item Can't "goto" out of a pseudo block
963 (F) A "goto" statement was executed to jump out of what might look like
964 a block, except that it isn't a proper block. This usually occurs if
965 you tried to jump out of a sort() block or subroutine, which is a no-no.
966 See L<perlfunc/goto>.
968 =item Can't goto subroutine from an eval-%s
970 (F) The "goto subroutine" call can't be used to jump out of an eval
973 =item Can't goto subroutine from a sort sub (or similar callback)
975 (F) The "goto subroutine" call can't be used to jump out of the
976 comparison sub for a sort(), or from a similar callback (such
977 as the reduce() function in List::Util).
979 =item Can't goto subroutine outside a subroutine
981 (F) The deeply magical "goto subroutine" call can only replace one
982 subroutine call for another. It can't manufacture one out of whole
983 cloth. In general you should be calling it out of only an AUTOLOAD
984 routine anyway. See L<perlfunc/goto>.
986 =item Can't ignore signal CHLD, forcing to default
988 (W signal) Perl has detected that it is being run with the SIGCHLD
989 signal (sometimes known as SIGCLD) disabled. Since disabling this
990 signal will interfere with proper determination of exit status of child
991 processes, Perl has reset the signal to its default value. This
992 situation typically indicates that the parent program under which Perl
993 may be running (e.g. cron) is being very careless.
995 =item Can't kill a non-numeric process ID
997 (F) Process identifiers must be (signed) integers. It is a fatal error to
998 attempt to kill() an undefined, empty-string or otherwise non-numeric
1001 =item Can't "last" outside a loop block
1003 (F) A "last" statement was executed to break out of the current block,
1004 except that there's this itty bitty problem called there isn't a current
1005 block. Note that an "if" or "else" block doesn't count as a "loopish"
1006 block, as doesn't a block given to sort(), map() or grep(). You can
1007 usually double the curlies to get the same effect though, because the
1008 inner curlies will be considered a block that loops once. See
1011 =item Can't linearize anonymous symbol table
1013 (F) Perl tried to calculate the method resolution order (MRO) of a
1014 package, but failed because the package stash has no name.
1016 =item Can't load '%s' for module %s
1018 (F) The module you tried to load failed to load a dynamic extension.
1019 This may either mean that you upgraded your version of perl to one
1020 that is incompatible with your old dynamic extensions (which is known
1021 to happen between major versions of perl), or (more likely) that your
1022 dynamic extension was built against an older version of the library
1023 that is installed on your system. You may need to rebuild your old
1026 =item Can't localize lexical variable %s
1028 (F) You used local on a variable name that was previously declared as a
1029 lexical variable using "my" or "state". This is not allowed. If you
1030 want to localize a package variable of the same name, qualify it with
1033 =item Can't localize through a reference
1035 (F) You said something like C<local $$ref>, which Perl can't currently
1036 handle, because when it goes to restore the old value of whatever $ref
1037 pointed to after the scope of the local() is finished, it can't be sure
1038 that $ref will still be a reference.
1040 =item Can't locate %s
1042 (F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be found.
1043 Perl looks for the file in all the locations mentioned in @INC, unless
1044 the file name included the full path to the file. Perhaps you need
1045 to set the PERL5LIB or PERL5OPT environment variable to say where the
1046 extra library is, or maybe the script needs to add the library name
1047 to @INC. Or maybe you just misspelled the name of the file. See
1048 L<perlfunc/require> and L<lib>.
1050 =item Can't locate auto/%s.al in @INC
1052 (F) A function (or method) was called in a package which allows
1053 autoload, but there is no function to autoload. Most probable causes
1054 are a misprint in a function/method name or a failure to C<AutoSplit>
1055 the file, say, by doing C<make install>.
1057 =item Can't locate loadable object for module %s in @INC
1059 (F) The module you loaded is trying to load an external library, like
1060 for example, F<foo.so> or F<bar.dll>, but the L<DynaLoader> module was
1061 unable to locate this library. See L<DynaLoader>.
1063 =item Can't locate object method "%s" via package "%s"
1065 (F) You called a method correctly, and it correctly indicated a package
1066 functioning as a class, but that package doesn't define that particular
1067 method, nor does any of its base classes. See L<perlobj>.
1069 =item Can't locate object method "%s" via package "%s" (perhaps you forgot
1072 (F) You called a method on a class that did not exist, and the method
1073 could not be found in UNIVERSAL. This often means that a method
1074 requires a package that has not been loaded.
1076 =item Can't locate package %s for @%s::ISA
1078 (W syntax) The @ISA array contained the name of another package that
1079 doesn't seem to exist.
1081 =item Can't locate PerlIO%s
1083 (F) You tried to use in open() a PerlIO layer that does not exist,
1084 e.g. open(FH, ">:nosuchlayer", "somefile").
1086 =item Can't make list assignment to %ENV on this system
1088 (F) List assignment to %ENV is not supported on some systems, notably
1091 =item Can't make loaded symbols global on this platform while loading %s
1093 (S) A module passed the flag 0x01 to DynaLoader::dl_load_file() to request
1094 that symbols from the stated file are made available globally within the
1095 process, but that functionality is not available on this platform. Whilst
1096 the module likely will still work, this may prevent the perl interpreter
1097 from loading other XS-based extensions which need to link directly to
1098 functions defined in the C or XS code in the stated file.
1100 =item Can't modify %s in %s
1102 (F) You aren't allowed to assign to the item indicated, or otherwise try
1103 to change it, such as with an auto-increment.
1105 =item Can't modify nonexistent substring
1107 (P) The internal routine that does assignment to a substr() was handed
1110 =item Can't modify non-lvalue subroutine call of &%s
1112 (F) Subroutines meant to be used in lvalue context should be declared as
1113 such. See L<perlsub/"Lvalue subroutines">.
1115 =item Can't modify reference to %s in %s assignment
1117 (F) Only a limited number of constructs can be used as the argument to a
1118 reference constructor on the left-hand side of an assignment, and what
1119 you used was not one of them. See L<perlref/Assigning to References>.
1121 =item Can't modify reference to localized parenthesized array in list
1124 (F) Assigning to C<\local(@array)> or C<\(local @array)> is not supported, as
1125 it is not clear exactly what it should do. If you meant to make @array
1126 refer to some other array, use C<\@array = \@other_array>. If you want to
1127 make the elements of @array aliases of the scalars referenced on the
1128 right-hand side, use C<\(@array) = @scalar_refs>.
1130 =item Can't modify reference to parenthesized hash in list assignment
1132 (F) Assigning to C<\(%hash)> is not supported. If you meant to make %hash
1133 refer to some other hash, use C<\%hash = \%other_hash>. If you want to
1134 make the elements of %hash into aliases of the scalars referenced on the
1135 right-hand side, use a hash slice: C<\@hash{@keys} = @those_scalar_refs>.
1137 =item Can't msgrcv to read-only var
1139 (F) The target of a msgrcv must be modifiable to be used as a receive
1142 =item Can't "next" outside a loop block
1144 (F) A "next" statement was executed to reiterate the current block, but
1145 there isn't a current block. Note that an "if" or "else" block doesn't
1146 count as a "loopish" block, as doesn't a block given to sort(), map() or
1147 grep(). You can usually double the curlies to get the same effect
1148 though, because the inner curlies will be considered a block that loops
1149 once. See L<perlfunc/next>.
1151 =item Can't open %s: %s
1153 (S inplace) The implicit opening of a file through use of the C<< <> >>
1154 filehandle, either implicitly under the C<-n> or C<-p> command-line
1155 switches, or explicitly, failed for the indicated reason. Usually
1156 this is because you don't have read permission for a file which
1157 you named on the command line.
1159 (F) You tried to call perl with the B<-e> switch, but F</dev/null> (or
1160 your operating system's equivalent) could not be opened.
1162 =item Can't open a reference
1164 (W io) You tried to open a scalar reference for reading or writing,
1165 using the 3-arg open() syntax:
1169 but your version of perl is compiled without perlio, and this form of
1170 open is not supported.
1172 =item Can't open bidirectional pipe
1174 (W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
1175 You can try any of several modules in the Perl library to do this, such
1176 as IPC::Open2. Alternately, direct the pipe's output to a file using
1177 ">", and then read it in under a different file handle.
1179 =item Can't open error file %s as stderr
1181 (F) An error peculiar to VMS. Perl does its own command line
1182 redirection, and couldn't open the file specified after '2>' or '2>>' on
1183 the command line for writing.
1185 =item Can't open input file %s as stdin
1187 (F) An error peculiar to VMS. Perl does its own command line
1188 redirection, and couldn't open the file specified after '<' on the
1189 command line for reading.
1191 =item Can't open output file %s as stdout
1193 (F) An error peculiar to VMS. Perl does its own command line
1194 redirection, and couldn't open the file specified after '>' or '>>' on
1195 the command line for writing.
1197 =item Can't open output pipe (name: %s)
1199 (P) An error peculiar to VMS. Perl does its own command line
1200 redirection, and couldn't open the pipe into which to send data destined
1203 =item Can't open perl script "%s": %s
1205 (F) The script you specified can't be opened for the indicated reason.
1207 If you're debugging a script that uses #!, and normally relies on the
1208 shell's $PATH search, the -S option causes perl to do that search, so
1209 you don't have to type the path or C<`which $scriptname`>.
1211 =item Can't read CRTL environ
1213 (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
1214 from the CRTL's internal environment array and discovered the array was
1215 missing. You need to figure out where your CRTL misplaced its environ
1216 or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
1219 =item Can't redeclare "%s" in "%s"
1221 (F) A "my", "our" or "state" declaration was found within another declaration,
1222 such as C<my ($x, my($y), $z)> or C<our (my $x)>.
1224 =item Can't "redo" outside a loop block
1226 (F) A "redo" statement was executed to restart the current block, but
1227 there isn't a current block. Note that an "if" or "else" block doesn't
1228 count as a "loopish" block, as doesn't a block given to sort(), map()
1229 or grep(). You can usually double the curlies to get the same effect
1230 though, because the inner curlies will be considered a block that
1231 loops once. See L<perlfunc/redo>.
1233 =item Can't remove %s: %s, skipping file
1235 (S inplace) You requested an inplace edit without creating a backup
1236 file. Perl was unable to remove the original file to replace it with
1237 the modified file. The file was left unmodified.
1239 =item Can't rename %s to %s: %s, skipping file
1241 (S inplace) The rename done by the B<-i> switch failed for some reason,
1242 probably because you don't have write permission to the directory.
1244 =item Can't reopen input pipe (name: %s) in binary mode
1246 (P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
1247 to reopen it to accept binary data. Alas, it failed.
1249 =item Can't represent character for Ox%X on this platform
1251 (F) There is a hard limit to how big a character code point can be due
1252 to the fundamental properties of UTF-8, especially on EBCDIC
1253 platforms. The given code point exceeds that. The only work-around is
1254 to not use such a large code point.
1256 =item Can't reset %ENV on this system
1258 (F) You called C<reset('E')> or similar, which tried to reset
1259 all variables in the current package beginning with "E". In
1260 the main package, that includes %ENV. Resetting %ENV is not
1261 supported on some systems, notably VMS.
1263 =item Can't resolve method "%s" overloading "%s" in package "%s"
1265 (F)(P) Error resolving overloading specified by a method name (as
1266 opposed to a subroutine reference): no such method callable via the
1267 package. If the method name is C<???>, this is an internal error.
1269 =item Can't return %s from lvalue subroutine
1271 (F) Perl detected an attempt to return illegal lvalues (such as
1272 temporary or readonly values) from a subroutine used as an lvalue. This
1275 =item Can't return outside a subroutine
1277 (F) The return statement was executed in mainline code, that is, where
1278 there was no subroutine call to return out of. See L<perlsub>.
1280 =item Can't return %s to lvalue scalar context
1282 (F) You tried to return a complete array or hash from an lvalue
1283 subroutine, but you called the subroutine in a way that made Perl
1284 think you meant to return only one value. You probably meant to
1285 write parentheses around the call to the subroutine, which tell
1286 Perl that the call should be in list context.
1288 =item Can't stat script "%s"
1290 (P) For some reason you can't fstat() the script even though you have it
1291 open already. Bizarre.
1293 =item Can't take log of %g
1295 (F) For ordinary real numbers, you can't take the logarithm of a
1296 negative number or zero. There's a Math::Complex package that comes
1297 standard with Perl, though, if you really want to do that for the
1300 =item Can't take sqrt of %g
1302 (F) For ordinary real numbers, you can't take the square root of a
1303 negative number. There's a Math::Complex package that comes standard
1304 with Perl, though, if you really want to do that.
1306 =item Can't undef active subroutine
1308 (F) You can't undefine a routine that's currently running. You can,
1309 however, redefine it while it's running, and you can even undef the
1310 redefined subroutine while the old routine is running. Go figure.
1312 =item Can't upgrade %s (%d) to %d
1314 (P) The internal sv_upgrade routine adds "members" to an SV, making it
1315 into a more specialized kind of SV. The top several SV types are so
1316 specialized, however, that they cannot be interconverted. This message
1317 indicates that such a conversion was attempted.
1319 =item Can't use '%c' after -mname
1321 (F) You tried to call perl with the B<-m> switch, but you put something
1322 other than "=" after the module name.
1324 =item Can't use a hash as a reference
1326 (F) You tried to use a hash as a reference, as in
1327 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl
1328 <= 5.22.0 used to allow this syntax, but shouldn't
1329 have. This was deprecated in perl 5.6.1.
1331 =item Can't use an array as a reference
1333 (F) You tried to use an array as a reference, as in
1334 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.22.0
1335 used to allow this syntax, but shouldn't have. This
1336 was deprecated in perl 5.6.1.
1338 =item Can't use anonymous symbol table for method lookup
1340 (F) The internal routine that does method lookup was handed a symbol
1341 table that doesn't have a name. Symbol tables can become anonymous
1342 for example by undefining stashes: C<undef %Some::Package::>.
1344 =item Can't use an undefined value as %s reference
1346 (F) A value used as either a hard reference or a symbolic reference must
1347 be a defined value. This helps to delurk some insidious errors.
1349 =item Can't use bareword ("%s") as %s ref while "strict refs" in use
1351 (F) Only hard references are allowed by "strict refs". Symbolic
1352 references are disallowed. See L<perlref>.
1354 =item Can't use %! because Errno.pm is not available
1356 (F) The first time the C<%!> hash is used, perl automatically loads the
1357 Errno.pm module. The Errno module is expected to tie the %! hash to
1358 provide symbolic names for C<$!> errno values.
1360 =item Can't use both '<' and '>' after type '%c' in %s
1362 (F) A type cannot be forced to have both big-endian and little-endian
1363 byte-order at the same time, so this combination of modifiers is not
1364 allowed. See L<perlfunc/pack>.
1366 =item Can't use 'defined(@array)' (Maybe you should just omit the defined()?)
1368 (F) defined() is not useful on arrays because it
1369 checks for an undefined I<scalar> value. If you want to see if the
1370 array is empty, just use C<if (@array) { # not empty }> for example.
1372 =item Can't use 'defined(%hash)' (Maybe you should just omit the defined()?)
1374 (F) C<defined()> is not usually right on hashes.
1376 Although C<defined %hash> is false on a plain not-yet-used hash, it
1377 becomes true in several non-obvious circumstances, including iterators,
1378 weak references, stash names, even remaining true after C<undef %hash>.
1379 These things make C<defined %hash> fairly useless in practice, so it now
1380 generates a fatal error.
1382 If a check for non-empty is what you wanted then just put it in boolean
1383 context (see L<perldata/Scalar values>):
1389 If you had C<defined %Foo::Bar::QUUX> to check whether such a package
1390 variable exists then that's never really been reliable, and isn't
1391 a good way to enquire about the features of a package, or whether
1394 =item Can't use %s for loop variable
1396 (P) The parser got confused when trying to parse a C<foreach> loop.
1398 =item Can't use global %s in "%s"
1400 (F) You tried to declare a magical variable as a lexical variable. This
1401 is not allowed, because the magic can be tied to only one location
1402 (namely the global variable) and it would be incredibly confusing to
1403 have variables in your program that looked like magical variables but
1406 =item Can't use '%c' in a group with different byte-order in %s
1408 (F) You attempted to force a different byte-order on a type
1409 that is already inside a group with a byte-order modifier.
1410 For example you cannot force little-endianness on a type that
1411 is inside a big-endian group.
1413 =item Can't use "my %s" in sort comparison
1415 (F) The global variables $a and $b are reserved for sort comparisons.
1416 You mentioned $a or $b in the same line as the <=> or cmp operator,
1417 and the variable had earlier been declared as a lexical variable.
1418 Either qualify the sort variable with the package name, or rename the
1421 =item Can't use %s ref as %s ref
1423 (F) You've mixed up your reference types. You have to dereference a
1424 reference of the type needed. You can use the ref() function to
1425 test the type of the reference, if need be.
1427 =item Can't use string ("%s") as %s ref while "strict refs" in use
1429 =item Can't use string ("%s"...) as %s ref while "strict refs" in use
1431 (F) You've told Perl to dereference a string, something which
1432 C<use strict> blocks to prevent it happening accidentally. See
1433 L<perlref/"Symbolic references">. This can be triggered by an C<@> or C<$>
1434 in a double-quoted string immediately before interpolating a variable,
1435 for example in C<"user @$twitter_id">, which says to treat the contents
1436 of C<$twitter_id> as an array reference; use a C<\> to have a literal C<@>
1437 symbol followed by the contents of C<$twitter_id>: C<"user \@$twitter_id">.
1439 =item Can't use subscript on %s
1441 (F) The compiler tried to interpret a bracketed expression as a
1442 subscript. But to the left of the brackets was an expression that
1443 didn't look like a hash or array reference, or anything else subscriptable.
1445 =item Can't use \%c to mean $%c in expression
1447 (W syntax) In an ordinary expression, backslash is a unary operator that
1448 creates a reference to its argument. The use of backslash to indicate a
1449 backreference to a matched substring is valid only as part of a regular
1450 expression pattern. Trying to do this in ordinary Perl code produces a
1451 value that prints out looking like SCALAR(0xdecaf). Use the $1 form
1454 =item Can't weaken a nonreference
1456 (F) You attempted to weaken something that was not a reference. Only
1457 references can be weakened.
1459 =item Can't "when" outside a topicalizer
1461 (F) You have used a when() block that is neither inside a C<foreach>
1462 loop nor a C<given> block. (Note that this error is issued on exit
1463 from the C<when> block, so you won't get the error if the match fails,
1464 or if you use an explicit C<continue>.)
1466 =item Can't x= to read-only value
1468 (F) You tried to repeat a constant value (often the undefined value)
1469 with an assignment operator, which implies modifying the value itself.
1470 Perhaps you need to copy the value to a temporary, and repeat that.
1472 =item Character following "\c" must be printable ASCII
1474 (F) In C<\cI<X>>, I<X> must be a printable (non-control) ASCII character.
1476 Note that ASCII characters that don't map to control characters are
1477 discouraged, and will generate the warning (when enabled)
1478 L</""\c%c" is more clearly written simply as "%s"">.
1480 =item Character following \%c must be '{' or a single-character Unicode property name in regex; marked by <-- HERE in m/%s/
1482 (F) (In the above the C<%c> is replaced by either C<p> or C<P>.) You
1483 specified something that isn't a legal Unicode property name. Most
1484 Unicode properties are specified by C<\p{...}>. But if the name is a
1485 single character one, the braces may be omitted.
1487 =item Character in 'C' format wrapped in pack
1493 where $x is either less than 0 or more than 255; the C<"C"> format is
1494 only for encoding native operating system characters (ASCII, EBCDIC,
1495 and so on) and not for Unicode characters, so Perl behaved as if you meant
1499 If you actually want to pack Unicode codepoints, use the C<"U"> format
1502 =item Character in 'c' format wrapped in pack
1508 where $x is either less than -128 or more than 127; the C<"c"> format
1509 is only for encoding native operating system characters (ASCII, EBCDIC,
1510 and so on) and not for Unicode characters, so Perl behaved as if you meant
1512 pack("c", $x & 255);
1514 If you actually want to pack Unicode codepoints, use the C<"U"> format
1517 =item Character in '%c' format wrapped in unpack
1519 (W unpack) You tried something like
1521 unpack("H", "\x{2a1}")
1523 where the format expects to process a byte (a character with a value
1524 below 256), but a higher value was provided instead. Perl uses the
1525 value modulus 256 instead, as if you had provided:
1527 unpack("H", "\x{a1}")
1529 =item Character in 'W' format wrapped in pack
1535 where $x is either less than 0 or more than 255. However, C<U0>-mode
1536 expects all values to fall in the interval [0, 255], so Perl behaved
1539 pack("U0W", $x & 255)
1541 =item Character(s) in '%c' format wrapped in pack
1543 (W pack) You tried something like
1545 pack("u", "\x{1f3}b")
1547 where the format expects to process a sequence of bytes (character with a
1548 value below 256), but some of the characters had a higher value. Perl
1549 uses the character values modulus 256 instead, as if you had provided:
1551 pack("u", "\x{f3}b")
1553 =item Character(s) in '%c' format wrapped in unpack
1555 (W unpack) You tried something like
1557 unpack("s", "\x{1f3}b")
1559 where the format expects to process a sequence of bytes (character with a
1560 value below 256), but some of the characters had a higher value. Perl
1561 uses the character values modulus 256 instead, as if you had provided:
1563 unpack("s", "\x{f3}b")
1565 =item charnames alias definitions may not contain a sequence of multiple spaces
1567 (F) You defined a character name which had multiple space characters
1568 in a row. Change them to single spaces. Usually these names are
1569 defined in the C<:alias> import argument to C<use charnames>, but they
1570 could be defined by a translator installed into C<$^H{charnames}>. See
1571 L<charnames/CUSTOM ALIASES>.
1573 =item charnames alias definitions may not contain trailing white-space
1575 (F) You defined a character name which ended in a space
1576 character. Remove the trailing space(s). Usually these names are
1577 defined in the C<:alias> import argument to C<use charnames>, but they
1578 could be defined by a translator installed into C<$^H{charnames}>.
1579 See L<charnames/CUSTOM ALIASES>.
1581 =item chdir() on unopened filehandle %s
1583 (W unopened) You tried chdir() on a filehandle that was never opened.
1585 =item \C no longer supported in regex; marked by S<<-- HERE> in m/%s/
1587 (F) The \C character class used to allow a match of single byte within a
1588 multi-byte utf-8 character, but was removed in v5.24 as it broke
1589 encapsulation and its implementation was extremely buggy. If you really
1590 need to process the individual bytes, you probably want to convert your
1591 string to one where each underlying byte is stored as a character, with
1594 =item "\c%c" is more clearly written simply as "%s"
1596 (W syntax) The C<\cI<X>> construct is intended to be a way to specify
1597 non-printable characters. You used it for a printable one, which
1598 is better written as simply itself, perhaps preceded by a backslash
1599 for non-word characters. Doing it the way you did is not portable
1600 between ASCII and EBCDIC platforms.
1602 =item Cloning substitution context is unimplemented
1604 (F) Creating a new thread inside the C<s///> operator is not supported.
1606 =item closedir() attempted on invalid dirhandle %s
1608 (W io) The dirhandle you tried to close is either closed or not really
1609 a dirhandle. Check your control flow.
1611 =item close() on unopened filehandle %s
1613 (W unopened) You tried to close a filehandle that was never opened.
1615 =item Closure prototype called
1617 (F) If a closure has attributes, the subroutine passed to an attribute
1618 handler is the prototype that is cloned when a new closure is created.
1619 This subroutine cannot be called.
1621 =item Code missing after '/'
1623 (F) You had a (sub-)template that ends with a '/'. There must be
1624 another template code following the slash. See L<perlfunc/pack>.
1626 =item Code point 0x%X is not Unicode, and not portable
1628 (S non_unicode) You had a code point that has never been in any
1629 standard, so it is likely that languages other than Perl will NOT
1630 understand it. At one time, it was legal in some standards to have code
1631 points up to 0x7FFF_FFFF, but not higher, and this code point is higher.
1633 Acceptance of these code points is a Perl extension, and you should
1634 expect that nothing other than Perl can handle them; Perl itself on
1635 EBCDIC platforms before v5.24 does not handle them.
1637 Code points above 0xFFFF_FFFF require larger than a 32 bit word.
1639 Perl also makes no guarantees that the representation of these code
1640 points won't change at some point in the future, say when machines
1641 become available that have larger than a 64-bit word. At that time,
1642 files written by an older Perl would require conversion before being
1643 readable by a newer Perl.
1645 =item Code point 0x%X is not Unicode, may not be portable
1647 (S non_unicode) You had a code point above the Unicode maximum
1650 Perl allows strings to contain a superset of Unicode code points, but
1651 these may not be accepted by other languages/systems. Further, even if
1652 these languages/systems accept these large code points, they may have
1653 chosen a different representation for them than the UTF-8-like one that
1654 Perl has, which would mean files are not exchangeable between them and
1657 On EBCDIC platforms, code points above 0x3FFF_FFFF have a different
1658 representation in Perl v5.24 than before, so any file containing these
1659 that was written before that version will require conversion before
1660 being readable by a later Perl.
1662 =item %s: Command not found
1664 (A) You've accidentally run your script through B<csh> or another shell
1665 instead of Perl. Check the #! line, or manually feed your script into
1666 Perl yourself. The #! line at the top of your file could look like
1670 =item Compilation failed in require
1672 (F) Perl could not compile a file specified in a C<require> statement.
1673 Perl uses this generic message when none of the errors that it
1674 encountered were severe enough to halt compilation immediately.
1676 =item Complex regular subexpression recursion limit (%d) exceeded
1678 (W regexp) The regular expression engine uses recursion in complex
1679 situations where back-tracking is required. Recursion depth is limited
1680 to 32766, or perhaps less in architectures where the stack cannot grow
1681 arbitrarily. ("Simple" and "medium" situations are handled without
1682 recursion and are not subject to a limit.) Try shortening the string
1683 under examination; looping in Perl code (e.g. with C<while>) rather than
1684 in the regular expression engine; or rewriting the regular expression so
1685 that it is simpler or backtracks less. (See L<perlfaq2> for information
1686 on I<Mastering Regular Expressions>.)
1688 =item connect() on closed socket %s
1690 (W closed) You tried to do a connect on a closed socket. Did you forget
1691 to check the return value of your socket() call? See
1692 L<perlfunc/connect>.
1694 =item Constant(%s): Call to &{$^H{%s}} did not return a defined value
1696 (F) The subroutine registered to handle constant overloading
1697 (see L<overload>) or a custom charnames handler (see
1698 L<charnames/CUSTOM TRANSLATORS>) returned an undefined value.
1700 =item Constant(%s): $^H{%s} is not defined
1702 (F) The parser found inconsistencies while attempting to define an
1703 overloaded constant. Perhaps you forgot to load the corresponding
1706 =item Constant is not %s reference
1708 (F) A constant value (perhaps declared using the C<use constant> pragma)
1709 is being dereferenced, but it amounts to the wrong type of reference.
1710 The message indicates the type of reference that was expected. This
1711 usually indicates a syntax error in dereferencing the constant value.
1712 See L<perlsub/"Constant Functions"> and L<constant>.
1714 =item Constants from lexical variables potentially modified elsewhere are
1717 (D deprecated) You wrote something like
1720 $sub = sub () { $var };
1722 but $var is referenced elsewhere and could be modified after the C<sub>
1723 expression is evaluated. Either it is explicitly modified elsewhere
1724 (C<$var = 3>) or it is passed to a subroutine or to an operator like
1725 C<printf> or C<map>, which may or may not modify the variable.
1727 Traditionally, Perl has captured the value of the variable at that
1728 point and turned the subroutine into a constant eligible for inlining.
1729 In those cases where the variable can be modified elsewhere, this
1730 breaks the behavior of closures, in which the subroutine captures
1731 the variable itself, rather than its value, so future changes to the
1732 variable are reflected in the subroutine's return value.
1734 This usage is deprecated, because the behavior is likely to change
1735 in a future version of Perl.
1737 If you intended for the subroutine to be eligible for inlining, then
1738 make sure the variable is not referenced elsewhere, possibly by
1742 $sub = sub () { $var2 };
1744 If you do want this subroutine to be a closure that reflects future
1745 changes to the variable that it closes over, add an explicit C<return>:
1748 $sub = sub () { return $var };
1750 =item Constant subroutine %s redefined
1752 (W redefine)(S) You redefined a subroutine which had previously
1753 been eligible for inlining. See L<perlsub/"Constant Functions">
1754 for commentary and workarounds.
1756 =item Constant subroutine %s undefined
1758 (W misc) You undefined a subroutine which had previously been eligible
1759 for inlining. See L<perlsub/"Constant Functions"> for commentary and
1762 =item Constant(%s) unknown
1764 (F) The parser found inconsistencies either while attempting
1765 to define an overloaded constant, or when trying to find the
1766 character name specified in the C<\N{...}> escape. Perhaps you
1767 forgot to load the corresponding L<overload> pragma?
1769 =item :const is experimental
1771 (S experimental::const_attr) The "const" attribute is experimental.
1772 If you want to use the feature, disable the warning with C<no warnings
1773 'experimental::const_attr'>, but know that in doing so you are taking
1774 the risk that your code may break in a future Perl version.
1776 =item :const is not permitted on named subroutines
1778 (F) The "const" attribute causes an anonymous subroutine to be run and
1779 its value captured at the time that it is cloned. Named subroutines are
1780 not cloned like this, so the attribute does not make sense on them.
1782 =item Copy method did not return a reference
1784 (F) The method which overloads "=" is buggy. See
1785 L<overload/Copy Constructor>.
1787 =item &CORE::%s cannot be called directly
1789 (F) You tried to call a subroutine in the C<CORE::> namespace
1790 with C<&foo> syntax or through a reference. Some subroutines
1791 in this package cannot yet be called that way, but must be
1792 called as barewords. Something like this will work:
1794 BEGIN { *shove = \&CORE::push; }
1795 shove @array, 1,2,3; # pushes on to @array
1797 =item CORE::%s is not a keyword
1799 (F) The CORE:: namespace is reserved for Perl keywords.
1801 =item Corrupted regexp opcode %d > %d
1803 (P) This is either an error in Perl, or, if you're using
1804 one, your L<custom regular expression engine|perlreapi>. If not the
1805 latter, report the problem through the L<perlbug> utility.
1807 =item corrupted regexp pointers
1809 (P) The regular expression engine got confused by what the regular
1810 expression compiler gave it.
1812 =item corrupted regexp program
1814 (P) The regular expression engine got passed a regexp program without a
1817 =item Corrupt malloc ptr 0x%x at 0x%x
1819 (P) The malloc package that comes with Perl had an internal failure.
1821 =item Count after length/code in unpack
1823 (F) You had an unpack template indicating a counted-length string, but
1824 you have also specified an explicit size for the string. See
1828 The following are used in lib/diagnostics.t for testing two =items that
1829 share the same description. Changes here need to be propagated to there
1831 =item Deep recursion on anonymous subroutine
1833 =item Deep recursion on subroutine "%s"
1835 (W recursion) This subroutine has called itself (directly or indirectly)
1836 100 times more than it has returned. This probably indicates an
1837 infinite recursion, unless you're writing strange benchmark programs, in
1838 which case it indicates something else.
1840 This threshold can be changed from 100, by recompiling the F<perl> binary,
1841 setting the C pre-processor macro C<PERL_SUB_DEPTH_WARN> to the desired value.
1843 =item (?(DEFINE)....) does not allow branches in regex; marked by
1844 S<<-- HERE> in m/%s/
1846 (F) You used something like C<(?(DEFINE)...|..)> which is illegal. The
1847 most likely cause of this error is that you left out a parenthesis inside
1848 of the C<....> part.
1850 The S<<-- HERE> shows whereabouts in the regular expression the problem was
1853 =item %s defines neither package nor VERSION--version check failed
1855 (F) You said something like "use Module 42" but in the Module file
1856 there are neither package declarations nor a C<$VERSION>.
1858 =item delete argument is index/value array slice, use array slice
1860 (F) You used index/value array slice syntax (C<%array[...]>) as
1861 the argument to C<delete>. You probably meant C<@array[...]> with
1862 an @ symbol instead.
1864 =item delete argument is key/value hash slice, use hash slice
1866 (F) You used key/value hash slice syntax (C<%hash{...}>) as the argument to
1867 C<delete>. You probably meant C<@hash{...}> with an @ symbol instead.
1869 =item delete argument is not a HASH or ARRAY element or slice
1871 (F) The argument to C<delete> must be either a hash or array element,
1877 or a hash or array slice, such as:
1879 @foo[$bar, $baz, $xyzzy]
1880 @{$ref->[12]}{"susie", "queue"}
1882 =item Delimiter for here document is too long
1884 (F) In a here document construct like C<<<FOO>, the label C<FOO> is too
1885 long for Perl to handle. You have to be seriously twisted to write code
1886 that triggers this error.
1888 =item Deprecated use of my() in false conditional
1890 (D deprecated) You used a declaration similar to C<my $x if 0>. There
1891 has been a long-standing bug in Perl that causes a lexical variable
1892 not to be cleared at scope exit when its declaration includes a false
1893 conditional. Some people have exploited this bug to achieve a kind of
1894 static variable. Since we intend to fix this bug, we don't want people
1895 relying on this behavior. You can achieve a similar static effect by
1896 declaring the variable in a separate block outside the function, eg
1898 sub f { my $x if 0; return $x++ }
1902 { my $x; sub f { return $x++ } }
1904 Beginning with perl 5.10.0, you can also use C<state> variables to have
1905 lexicals that are initialized only once (see L<feature>):
1907 sub f { state $x; return $x++ }
1909 =item DESTROY created new reference to dead object '%s'
1911 (F) A DESTROY() method created a new reference to the object which is
1912 just being DESTROYed. Perl is confused, and prefers to abort rather
1913 than to create a dangling reference.
1915 =item Did not produce a valid header
1919 =item %s did not return a true value
1921 (F) A required (or used) file must return a true value to indicate that
1922 it compiled correctly and ran its initialization code correctly. It's
1923 traditional to end such a file with a "1;", though any true value would
1924 do. See L<perlfunc/require>.
1926 =item (Did you mean &%s instead?)
1928 (W misc) You probably referred to an imported subroutine &FOO as $FOO or
1931 =item (Did you mean "local" instead of "our"?)
1933 (W misc) Remember that "our" does not localize the declared global
1934 variable. You have declared it again in the same lexical scope, which
1937 =item (Did you mean $ or @ instead of %?)
1939 (W) You probably said %hash{$key} when you meant $hash{$key} or
1940 @hash{@keys}. On the other hand, maybe you just meant %hash and got
1945 (F) You passed die() an empty string (the equivalent of C<die "">) or
1946 you called it with no args and C<$@> was empty.
1948 =item Document contains no data
1952 =item %s does not define %s::VERSION--version check failed
1954 (F) You said something like "use Module 42" but the Module did not
1955 define a C<$VERSION>.
1957 =item '/' does not take a repeat count
1959 (F) You cannot put a repeat count of any kind right after the '/' code.
1960 See L<perlfunc/pack>.
1962 =item Don't know how to get file name
1964 (P) C<PerlIO_getname>, a perl internal I/O function specific to VMS, was
1965 somehow called on another platform. This should not happen.
1967 =item Don't know how to handle magic of type \%o
1969 (P) The internal handling of magical variables has been cursed.
1971 =item do_study: out of memory
1973 (P) This should have been caught by safemalloc() instead.
1975 =item (Do you need to predeclare %s?)
1977 (S syntax) This is an educated guess made in conjunction with the message
1978 "%s found where operator expected". It often means a subroutine or module
1979 name is being referenced that hasn't been declared yet. This may be
1980 because of ordering problems in your file, or because of a missing
1981 "sub", "package", "require", or "use" statement. If you're referencing
1982 something that isn't defined yet, you don't actually have to define the
1983 subroutine or package before the current location. You can use an empty
1984 "sub foo;" or "package FOO;" to enter a "forward" declaration.
1986 =item dump() better written as CORE::dump()
1988 (W misc) You used the obsolescent C<dump()> built-in function, without fully
1989 qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
1991 =item dump is not supported
1993 (F) Your machine doesn't support dump/undump.
1995 =item Duplicate free() ignored
1997 (S malloc) An internal routine called free() on something that had
2000 =item Duplicate modifier '%c' after '%c' in %s
2002 (W unpack) You have applied the same modifier more than once after a
2003 type in a pack template. See L<perlfunc/pack>.
2005 =item elseif should be elsif
2007 (S syntax) There is no keyword "elseif" in Perl because Larry thinks
2008 it's ugly. Your code will be interpreted as an attempt to call a method
2009 named "elseif" for the class returned by the following block. This is
2010 unlikely to be what you want.
2012 =item Empty \%c{} in regex; marked by S<<-- HERE> in m/%s/
2014 (F) C<\p> and C<\P> are used to introduce a named Unicode property, as
2015 described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
2016 a regular expression without specifying the property name.
2018 =item entering effective %s failed
2020 (F) While under the C<use filetest> pragma, switching the real and
2021 effective uids or gids failed.
2023 =item %ENV is aliased to %s
2025 (F) You're running under taint mode, and the C<%ENV> variable has been
2026 aliased to another hash, so it doesn't reflect anymore the state of the
2027 program's environment. This is potentially insecure.
2029 =item Error converting file specification %s
2031 (F) An error peculiar to VMS. Because Perl may have to deal with file
2032 specifications in either VMS or Unix syntax, it converts them to a
2033 single form when it must operate on them directly. Either you've passed
2034 an invalid file specification to Perl, or you've found a case the
2035 conversion routines don't handle. Drat.
2037 =item Eval-group in insecure regular expression
2039 (F) Perl detected tainted data when trying to compile a regular
2040 expression that contains the C<(?{ ... })> zero-width assertion, which
2041 is unsafe. See L<perlre/(?{ code })>, and L<perlsec>.
2043 =item Eval-group not allowed at runtime, use re 'eval' in regex m/%s/
2045 (F) Perl tried to compile a regular expression containing the
2046 C<(?{ ... })> zero-width assertion at run time, as it would when the
2047 pattern contains interpolated values. Since that is a security risk,
2048 it is not allowed. If you insist, you may still do this by using the
2049 C<re 'eval'> pragma or by explicitly building the pattern from an
2050 interpolated string at run time and using that in an eval(). See
2051 L<perlre/(?{ code })>.
2053 =item Eval-group not allowed, use re 'eval' in regex m/%s/
2055 (F) A regular expression contained the C<(?{ ... })> zero-width
2056 assertion, but that construct is only allowed when the C<use re 'eval'>
2057 pragma is in effect. See L<perlre/(?{ code })>.
2059 =item EVAL without pos change exceeded limit in regex; marked by
2060 S<<-- HERE> in m/%s/
2062 (F) You used a pattern that nested too many EVAL calls without consuming
2063 any text. Restructure the pattern so that text is consumed.
2065 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2068 =item Excessively long <> operator
2070 (F) The contents of a <> operator may not exceed the maximum size of a
2071 Perl identifier. If you're just trying to glob a long list of
2072 filenames, try using the glob() operator, or put the filenames into a
2073 variable and glob that.
2075 =item exec? I'm not *that* kind of operating system
2077 (F) The C<exec> function is not implemented on some systems, e.g., Symbian
2078 OS. See L<perlport>.
2080 =item Execution of %s aborted due to compilation errors.
2082 (F) The final summary message when a Perl compilation fails.
2084 =item exists argument is not a HASH or ARRAY element or a subroutine
2086 (F) The argument to C<exists> must be a hash or array element or a
2087 subroutine with an ampersand, such as:
2093 =item exists argument is not a subroutine name
2095 (F) The argument to C<exists> for C<exists &sub> must be a subroutine name,
2096 and not a subroutine call. C<exists &sub()> will generate this error.
2098 =item Exiting eval via %s
2100 (W exiting) You are exiting an eval by unconventional means, such as a
2101 goto, or a loop control statement.
2103 =item Exiting format via %s
2105 (W exiting) You are exiting a format by unconventional means, such as a
2106 goto, or a loop control statement.
2108 =item Exiting pseudo-block via %s
2110 (W exiting) You are exiting a rather special block construct (like a
2111 sort block or subroutine) by unconventional means, such as a goto, or a
2112 loop control statement. See L<perlfunc/sort>.
2114 =item Exiting subroutine via %s
2116 (W exiting) You are exiting a subroutine by unconventional means, such
2117 as a goto, or a loop control statement.
2119 =item Exiting substitution via %s
2121 (W exiting) You are exiting a substitution by unconventional means, such
2122 as a return, a goto, or a loop control statement.
2124 =item Expecting close bracket in regex; marked by S<<-- HERE> in m/%s/
2126 (F) You wrote something like
2130 to denote a capturing group of the form
2131 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>,
2132 but omitted the C<")">.
2134 =item Expecting '(?flags:(?[...' in regex; marked by S<<-- HERE> in m/%s/
2136 (F) The C<(?[...])> extended character class regular expression construct
2137 only allows character classes (including character class escapes like
2138 C<\d>), operators, and parentheses. The one exception is C<(?flags:...)>
2139 containing at least one flag and exactly one C<(?[...])> construct.
2140 This allows a regular expression containing just C<(?[...])> to be
2141 interpolated. If you see this error message, then you probably
2142 have some other C<(?...)> construct inside your character class. See
2143 L<perlrecharclass/Extended Bracketed Character Classes>.
2145 =item Experimental aliasing via reference not enabled
2147 (F) To do aliasing via references, you must first enable the feature:
2149 no warnings "experimental::refaliasing";
2150 use feature "refaliasing";
2153 =item Experimental subroutine signatures not enabled
2155 (F) To use subroutine signatures, you must first enable them:
2157 no warnings "experimental::signatures";
2158 use feature "signatures";
2159 sub foo ($left, $right) { ... }
2161 =item Experimental %s on scalar is now forbidden
2163 (F) An experimental feature added in Perl 5.14 allowed C<each>, C<keys>,
2164 C<push>, C<pop>, C<shift>, C<splice>, C<unshift>, and C<values> to be called
2165 with a scalar argument. This experiment is considered unsuccessful, and has
2166 been removed. The C<postderef> feature may meet your needs better.
2168 =item Experimental "%s" subs not enabled
2170 (F) To use lexical subs, you must first enable them:
2172 no warnings 'experimental::lexical_subs';
2173 use feature 'lexical_subs';
2176 =item Explicit blessing to '' (assuming package main)
2178 (W misc) You are blessing a reference to a zero length string. This has
2179 the effect of blessing the reference into the package main. This is
2180 usually not what you want. Consider providing a default target package,
2181 e.g. bless($ref, $p || 'MyPackage');
2183 =item %s: Expression syntax
2185 (A) You've accidentally run your script through B<csh> instead of Perl.
2186 Check the #! line, or manually feed your script into Perl yourself.
2188 =item %s failed--call queue aborted
2190 (F) An untrapped exception was raised while executing a UNITCHECK,
2191 CHECK, INIT, or END subroutine. Processing of the remainder of the
2192 queue of such routines has been prematurely ended.
2194 =item False [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2196 (W regexp)(F) A character class range must start and end at a literal
2197 character, not another character class like C<\d> or C<[:alpha:]>. The "-"
2198 in your false range is interpreted as a literal "-". In a C<(?[...])>
2199 construct, this is an error, rather than a warning. Consider quoting
2200 the "-", "\-". The S<<-- HERE> shows whereabouts in the regular expression
2201 the problem was discovered. See L<perlre>.
2203 =item Fatal VMS error (status=%d) at %s, line %d
2205 (P) An error peculiar to VMS. Something untoward happened in a VMS
2206 system service or RTL routine; Perl's exit status should provide more
2207 details. The filename in "at %s" and the line number in "line %d" tell
2208 you which section of the Perl source code is distressed.
2210 =item fcntl is not implemented
2212 (F) Your machine apparently doesn't implement fcntl(). What is this, a
2213 PDP-11 or something?
2215 =item FETCHSIZE returned a negative value
2217 (F) A tied array claimed to have a negative number of elements, which
2220 =item Field too wide in 'u' format in pack
2222 (W pack) Each line in an uuencoded string starts with a length indicator
2223 which can't encode values above 63. So there is no point in asking for
2224 a line length bigger than that. Perl will behave as if you specified
2225 C<u63> as the format.
2227 =item Filehandle %s opened only for input
2229 (W io) You tried to write on a read-only filehandle. If you intended
2230 it to be a read-write filehandle, you needed to open it with "+<" or
2231 "+>" or "+>>" instead of with "<" or nothing. If you intended only to
2232 write the file, use ">" or ">>". See L<perlfunc/open>.
2234 =item Filehandle %s opened only for output
2236 (W io) You tried to read from a filehandle opened only for writing, If
2237 you intended it to be a read/write filehandle, you needed to open it
2238 with "+<" or "+>" or "+>>" instead of with ">". If you intended only to
2239 read from the file, use "<". See L<perlfunc/open>. Another possibility
2240 is that you attempted to open filedescriptor 0 (also known as STDIN) for
2241 output (maybe you closed STDIN earlier?).
2243 =item Filehandle %s reopened as %s only for input
2245 (W io) You opened for reading a filehandle that got the same filehandle id
2246 as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR
2249 =item Filehandle STDIN reopened as %s only for output
2251 (W io) You opened for writing a filehandle that got the same filehandle id
2252 as STDIN. This occurred because you closed STDIN previously.
2254 =item Final $ should be \$ or $name
2256 (F) You must now decide whether the final $ in a string was meant to be
2257 a literal dollar sign, or was meant to introduce a variable name that
2258 happens to be missing. So you have to put either the backslash or the
2261 =item flock() on closed filehandle %s
2263 (W closed) The filehandle you're attempting to flock() got itself closed
2264 some time before now. Check your control flow. flock() operates on
2265 filehandles. Are you attempting to call flock() on a dirhandle by the
2268 =item Format not terminated
2270 (F) A format must be terminated by a line with a solitary dot. Perl got
2271 to the end of your file without finding such a line.
2273 =item Format %s redefined
2275 (W redefine) You redefined a format. To suppress this warning, say
2278 no warnings 'redefine';
2279 eval "format NAME =...";
2282 =item Found = in conditional, should be ==
2292 (or something like that).
2294 =item %s found where operator expected
2296 (S syntax) The Perl lexer knows whether to expect a term or an operator.
2297 If it sees what it knows to be a term when it was expecting to see an
2298 operator, it gives you this warning. Usually it indicates that an
2299 operator or delimiter was omitted, such as a semicolon.
2301 =item gdbm store returned %d, errno %d, key "%s"
2303 (S) A warning from the GDBM_File extension that a store failed.
2305 =item gethostent not implemented
2307 (F) Your C library apparently doesn't implement gethostent(), probably
2308 because if it did, it'd feel morally obligated to return every hostname
2311 =item get%sname() on closed socket %s
2313 (W closed) You tried to get a socket or peer socket name on a closed
2314 socket. Did you forget to check the return value of your socket() call?
2316 =item getpwnam returned invalid UIC %#o for user "%s"
2318 (S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
2319 C<getpwnam> operator returned an invalid UIC.
2321 =item getsockopt() on closed socket %s
2323 (W closed) You tried to get a socket option on a closed socket. Did you
2324 forget to check the return value of your socket() call? See
2325 L<perlfunc/getsockopt>.
2327 =item given is experimental
2329 (S experimental::smartmatch) C<given> depends on smartmatch, which
2330 is experimental, so its behavior may change or even be removed
2331 in any future release of perl. See the explanation under
2332 L<perlsyn/Experimental Details on given and when>.
2334 =item Global symbol "%s" requires explicit package name (did you forget to
2337 (F) You've said "use strict" or "use strict vars", which indicates
2338 that all variables must either be lexically scoped (using "my" or "state"),
2339 declared beforehand using "our", or explicitly qualified to say
2340 which package the global variable is in (using "::").
2342 =item glob failed (%s)
2344 (S glob) Something went wrong with the external program(s) used
2345 for C<glob> and C<< <*.c> >>. Usually, this means that you supplied a C<glob>
2346 pattern that caused the external program to fail and exit with a
2347 nonzero status. If the message indicates that the abnormal exit
2348 resulted in a coredump, this may also mean that your csh (C shell)
2349 is broken. If so, you should change all of the csh-related variables
2350 in config.sh: If you have tcsh, make the variables refer to it as
2351 if it were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them
2352 all empty (except that C<d_csh> should be C<'undef'>) so that Perl will
2353 think csh is missing. In either case, after editing config.sh, run
2354 C<./Configure -S> and rebuild Perl.
2356 =item Glob not terminated
2358 (F) The lexer saw a left angle bracket in a place where it was expecting
2359 a term, so it's looking for the corresponding right angle bracket, and
2360 not finding it. Chances are you left some needed parentheses out
2361 earlier in the line, and you really meant a "less than".
2363 =item gmtime(%f) failed
2365 (W overflow) You called C<gmtime> with a number that it could not handle:
2366 too large, too small, or NaN. The returned value is C<undef>.
2368 =item gmtime(%f) too large
2370 (W overflow) You called C<gmtime> with a number that was larger than
2371 it can reliably handle and C<gmtime> probably returned the wrong
2372 date. This warning is also triggered with NaN (the special
2373 not-a-number value).
2375 =item gmtime(%f) too small
2377 (W overflow) You called C<gmtime> with a number that was smaller than
2378 it can reliably handle and C<gmtime> probably returned the wrong date.
2380 =item Got an error from DosAllocMem
2382 (P) An error peculiar to OS/2. Most probably you're using an obsolete
2383 version of Perl, and this should not happen anyway.
2385 =item goto must have label
2387 (F) Unlike with "next" or "last", you're not allowed to goto an
2388 unspecified destination. See L<perlfunc/goto>.
2390 =item Goto undefined subroutine%s
2392 (F) You tried to call a subroutine with C<goto &sub> syntax, but
2393 the indicated subroutine hasn't been defined, or if it was, it
2394 has since been undefined.
2396 =item Group name must start with a non-digit word character in regex; marked by
2397 S<<-- HERE> in m/%s/
2399 (F) Group names must follow the rules for perl identifiers, meaning
2400 they must start with a non-digit word character. A common cause of
2401 this error is using (?&0) instead of (?0). See L<perlre>.
2403 =item ()-group starts with a count
2405 (F) A ()-group started with a count. A count is supposed to follow
2406 something: a template character or a ()-group. See L<perlfunc/pack>.
2408 =item %s had compilation errors.
2410 (F) The final summary message when a C<perl -c> fails.
2412 =item Had to create %s unexpectedly
2414 (S internal) A routine asked for a symbol from a symbol table that ought
2415 to have existed already, but for some reason it didn't, and had to be
2416 created on an emergency basis to prevent a core dump.
2418 =item %s has too many errors
2420 (F) The parser has given up trying to parse the program after 10 errors.
2421 Further error messages would likely be uninformative.
2423 =item Having more than one /%c regexp modifier is deprecated
2425 (D deprecated, regexp) You used the indicated regular expression pattern
2426 modifier at least twice in a string of modifiers. It is deprecated to
2427 do this with this particular modifier, to allow future extensions to the
2430 =item Hexadecimal float: exponent overflow
2432 (W overflow) The hexadecimal floating point has a larger exponent
2433 than the floating point supports.
2435 =item Hexadecimal float: exponent underflow
2437 (W overflow) The hexadecimal floating point has a smaller exponent
2438 than the floating point supports.
2440 =item Hexadecimal float: internal error (%s)
2442 (F) Something went horribly bad in hexadecimal float handling.
2444 =item Hexadecimal float: mantissa overflow
2446 (W overflow) The hexadecimal floating point literal had more bits in
2447 the mantissa (the part between the 0x and the exponent, also known as
2448 the fraction or the significand) than the floating point supports.
2450 =item Hexadecimal float: precision loss
2452 (W overflow) The hexadecimal floating point had internally more
2453 digits than could be output. This can be caused by unsupported
2454 long double formats, or by 64-bit integers not being available
2455 (needed to retrieve the digits under some configurations).
2457 =item Hexadecimal float: unsupported long double format
2459 (F) You have configured Perl to use long doubles but
2460 the internals of the long double format are unknown;
2461 therefore the hexadecimal float output is impossible.
2463 =item Hexadecimal number > 0xffffffff non-portable
2465 (W portable) The hexadecimal number you specified is larger than 2**32-1
2466 (4294967295) and therefore non-portable between systems. See
2467 L<perlport> for more on portability concerns.
2469 =item Identifier too long
2471 (F) Perl limits identifiers (names for variables, functions, etc.) to
2472 about 250 characters for simple names, and somewhat more for compound
2473 names (like C<$A::B>). You've exceeded Perl's limits. Future versions
2474 of Perl are likely to eliminate these arbitrary limitations.
2476 =item Ignoring zero length \N{} in character class in regex; marked by
2477 S<<-- HERE> in m/%s/
2479 (W regexp) Named Unicode character escapes (C<\N{...}>) may return a
2480 zero-length sequence. When such an escape is used in a character
2481 class its behavior is not well defined. Check that the correct
2482 escape has been used, and the correct charname handler is in scope.
2484 =item Illegal binary digit %s
2486 (F) You used a digit other than 0 or 1 in a binary number.
2488 =item Illegal binary digit %s ignored
2490 (W digit) You may have tried to use a digit other than 0 or 1 in a
2491 binary number. Interpretation of the binary number stopped before the
2494 =item Illegal character after '_' in prototype for %s : %s
2496 (W illegalproto) An illegal character was found in a prototype
2497 declaration. The '_' in a prototype must be followed by a ';',
2498 indicating the rest of the parameters are optional, or one of '@'
2499 or '%', since those two will accept 0 or more final parameters.
2501 =item Illegal character \%o (carriage return)
2503 (F) Perl normally treats carriage returns in the program text as it
2504 would any other whitespace, which means you should never see this error
2505 when Perl was built using standard options. For some reason, your
2506 version of Perl appears to have been built without this support. Talk
2507 to your Perl administrator.
2509 =item Illegal character in prototype for %s : %s
2511 (W illegalproto) An illegal character was found in a prototype declaration.
2512 Legal characters in prototypes are $, @, %, *, ;, [, ], &, \, and +.
2513 Perhaps you were trying to write a subroutine signature but didn't enable
2514 that feature first (C<use feature 'signatures'>), so your signature was
2515 instead interpreted as a bad prototype.
2517 =item Illegal declaration of anonymous subroutine
2519 (F) When using the C<sub> keyword to construct an anonymous subroutine,
2520 you must always specify a block of code. See L<perlsub>.
2522 =item Illegal declaration of subroutine %s
2524 (F) A subroutine was not declared correctly. See L<perlsub>.
2526 =item Illegal division by zero
2528 (F) You tried to divide a number by 0. Either something was wrong in
2529 your logic, or you need to put a conditional in to guard against
2532 =item Illegal hexadecimal digit %s ignored
2534 (W digit) You may have tried to use a character other than 0 - 9 or
2535 A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
2536 number stopped before the illegal character.
2538 =item Illegal modulus zero
2540 (F) You tried to divide a number by 0 to get the remainder. Most
2541 numbers don't take to this kindly.
2543 =item Illegal number of bits in vec
2545 (F) The number of bits in vec() (the third argument) must be a power of
2546 two from 1 to 32 (or 64, if your platform supports that).
2548 =item Illegal octal digit %s
2550 (F) You used an 8 or 9 in an octal number.
2552 =item Illegal octal digit %s ignored
2554 (W digit) You may have tried to use an 8 or 9 in an octal number.
2555 Interpretation of the octal number stopped before the 8 or 9.
2557 =item Illegal pattern in regex; marked by S<<-- HERE> in m/%s/
2559 (F) You wrote something like
2563 The C<"+"> is valid only when followed by digits, indicating a
2564 capturing group. See
2565 L<C<(?I<PARNO>)>|perlre/(?PARNO) (?-PARNO) (?+PARNO) (?R) (?0)>.
2567 =item Illegal suidscript
2569 (F) The script run under suidperl was somehow illegal.
2571 =item Illegal switch in PERL5OPT: -%c
2573 (X) The PERL5OPT environment variable may only be used to set the
2574 following switches: B<-[CDIMUdmtw]>.
2576 =item Illegal user-defined property name
2578 (F) You specified a Unicode-like property name in a regular expression
2579 pattern (using C<\p{}> or C<\P{}>) that Perl knows isn't an official
2580 Unicode property, and was likely meant to be a user-defined property
2581 name, but it can't be one of those, as they must begin with either C<In>
2582 or C<Is>. Check the spelling. See also
2583 L</Can't find Unicode property definition "%s">.
2585 =item Ill-formed CRTL environ value "%s"
2587 (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
2588 internal environ array, and encountered an element without the C<=>
2589 delimiter used to separate keys from values. The element is ignored.
2591 =item Ill-formed message in prime_env_iter: |%s|
2593 (W internal) A warning peculiar to VMS. Perl tried to read a logical
2594 name or CLI symbol definition when preparing to iterate over %ENV, and
2595 didn't see the expected delimiter between key and value, so the line was
2598 =item (in cleanup) %s
2600 (W misc) This prefix usually indicates that a DESTROY() method raised
2601 the indicated exception. Since destructors are usually called by the
2602 system at arbitrary points during execution, and often a vast number of
2603 times, the warning is issued only once for any number of failures that
2604 would otherwise result in the same message being repeated.
2606 Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
2607 also result in this warning. See L<perlcall/G_KEEPERR>.
2609 =item Incomplete expression within '(?[ ])' in regex; marked by S<<-- HERE>
2612 (F) There was a syntax error within the C<(?[ ])>. This can happen if the
2613 expression inside the construct was completely empty, or if there are
2614 too many or few operands for the number of operators. Perl is not smart
2615 enough to give you a more precise indication as to what is wrong.
2617 =item Inconsistent hierarchy during C3 merge of class '%s': merging failed on
2620 (F) The method resolution order (MRO) of the given class is not
2621 C3-consistent, and you have enabled the C3 MRO for this class. See the C3
2622 documentation in L<mro> for more information.
2624 =item Infinite recursion in regex
2626 (F) You used a pattern that references itself without consuming any input
2627 text. You should check the pattern to ensure that recursive patterns
2628 either consume text or fail.
2630 =item Initialization of state variables in list context currently forbidden
2632 (F) Currently the implementation of "state" only permits the
2633 initialization of scalar variables in scalar context. Re-write
2634 C<state ($a) = 42> as C<state $a = 42> to change from list to scalar
2635 context. Constructions such as C<state (@a) = foo()> will be
2636 supported in a future perl release.
2638 =item %%s[%s] in scalar context better written as $%s[%s]
2640 (W syntax) In scalar context, you've used an array index/value slice
2641 (indicated by %) to select a single element of an array. Generally
2642 it's better to ask for a scalar value (indicated by $). The difference
2643 is that C<$foo[&bar]> always behaves like a scalar, both in the value it
2644 returns and when evaluating its argument, while C<%foo[&bar]> provides
2645 a list context to its subscript, which can do weird things if you're
2646 expecting only one subscript. When called in list context, it also
2647 returns the index (what C<&bar> returns) in addition to the value.
2649 =item %%s{%s} in scalar context better written as $%s{%s}
2651 (W syntax) In scalar context, you've used a hash key/value slice
2652 (indicated by %) to select a single element of a hash. Generally it's
2653 better to ask for a scalar value (indicated by $). The difference
2654 is that C<$foo{&bar}> always behaves like a scalar, both in the value
2655 it returns and when evaluating its argument, while C<@foo{&bar}> and
2656 provides a list context to its subscript, which can do weird things
2657 if you're expecting only one subscript. When called in list context,
2658 it also returns the key in addition to the value.
2660 =item Invalid number '%s' for -C option.
2662 (F) You supplied a number to the -C option that either has extra leading
2663 zeroes or overflows perl's unsigned integer representation.
2665 =item %s() is deprecated on :utf8 handles
2667 (W deprecated) The sysread(), recv(), syswrite() and send() operators
2668 are deprecated on handles that have the C<:utf8> layer, either
2669 explicitly, or implicitly, eg., with the C<:encoding(UTF-16LE)> layer.
2671 Both sysread() and recv() currently use only the C<:utf8> flag for the
2672 stream, ignoring the actual layers. Since sysread() and recv() do no
2673 UTF-8 validation they can end up creating invalidly encoded scalars.
2675 Similarly, syswrite() and send() use only the C<:utf8> flag, otherwise
2676 ignoring any layers. If the flag is set, both write the value UTF-8
2677 encoded, even if the layer is some different encoding, such as the
2680 Ideally, all of these operators would completely ignore the C<:utf8>
2681 state, working only with bytes, but this would result in silently
2682 breaking existing code. To avoid this a future version of perl will
2683 throw an exception when any of sysread(), recv(), syswrite() or send()
2684 are called on handle with the C<:utf8> layer.
2686 =item Insecure dependency in %s
2688 (F) You tried to do something that the tainting mechanism didn't like.
2689 The tainting mechanism is turned on when you're running setuid or
2690 setgid, or when you specify B<-T> to turn it on explicitly. The
2691 tainting mechanism labels all data that's derived directly or indirectly
2692 from the user, who is considered to be unworthy of your trust. If any
2693 such data is used in a "dangerous" operation, you get this error. See
2694 L<perlsec> for more information.
2696 =item Insecure directory in %s
2698 (F) You can't use system(), exec(), or a piped open in a setuid or
2699 setgid script if C<$ENV{PATH}> contains a directory that is writable by
2700 the world. Also, the PATH must not contain any relative directory.
2703 =item Insecure $ENV{%s} while running %s
2705 (F) You can't use system(), exec(), or a piped open in a setuid or
2706 setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
2707 C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
2708 supplied (or potentially supplied) by the user. The script must set
2709 the path to a known value, using trustworthy data. See L<perlsec>.
2711 =item Insecure user-defined property %s
2713 (F) Perl detected tainted data when trying to compile a regular
2714 expression that contains a call to a user-defined character property
2715 function, i.e. C<\p{IsFoo}> or C<\p{InFoo}>.
2716 See L<perlunicode/User-Defined Character Properties> and L<perlsec>.
2718 =item Integer overflow in format string for %s
2720 (F) The indexes and widths specified in the format string of C<printf()>
2721 or C<sprintf()> are too large. The numbers must not overflow the size of
2722 integers for your architecture.
2724 =item Integer overflow in %s number
2726 (S overflow) The hexadecimal, octal or binary number you have specified
2727 either as a literal or as an argument to hex() or oct() is too big for
2728 your architecture, and has been converted to a floating point number.
2729 On a 32-bit architecture the largest hexadecimal, octal or binary number
2730 representable without overflow is 0xFFFFFFFF, 037777777777, or
2731 0b11111111111111111111111111111111 respectively. Note that Perl
2732 transparently promotes all numbers to a floating point representation
2733 internally--subject to loss of precision errors in subsequent
2736 =item Integer overflow in srand
2738 (S overflow) The number you have passed to srand is too big to fit
2739 in your architecture's integer representation. The number has been
2740 replaced with the largest integer supported (0xFFFFFFFF on 32-bit
2741 architectures). This means you may be getting less randomness than
2742 you expect, because different random seeds above the maximum will
2743 return the same sequence of random numbers.
2745 =item Integer overflow in version
2747 =item Integer overflow in version %d
2749 (W overflow) Some portion of a version initialization is too large for
2750 the size of integers for your architecture. This is not a warning
2751 because there is no rational reason for a version to try and use an
2752 element larger than typically 2**32. This is usually caused by trying
2753 to use some odd mathematical operation as a version, like 100/9.
2755 =item Internal disaster in regex; marked by S<<-- HERE> in m/%s/
2757 (P) Something went badly wrong in the regular expression parser.
2758 The S<<-- HERE> shows whereabouts in the regular expression the problem was
2761 =item Internal inconsistency in tracking vforks
2763 (S) A warning peculiar to VMS. Perl keeps track of the number of times
2764 you've called C<fork> and C<exec>, to determine whether the current call
2765 to C<exec> should affect the current script or a subprocess (see
2766 L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
2767 Perl is making a guess and treating this C<exec> as a request to
2768 terminate the Perl script and execute the specified command.
2770 =item internal %<num>p might conflict with future printf extensions
2772 (S internal) Perl's internal routine that handles C<printf> and C<sprintf>
2773 formatting follows a slightly different set of rules when called from
2774 C or XS code. Specifically, formats consisting of digits followed
2775 by "p" (e.g., "%7p") are reserved for future use. If you see this
2776 message, then an XS module tried to call that routine with one such
2779 =item Internal urp in regex; marked by S<<-- HERE> in m/%s/
2781 (P) Something went badly awry in the regular expression parser. The
2782 S<<-- HERE> shows whereabouts in the regular expression the problem was
2785 =item %s (...) interpreted as function
2787 (W syntax) You've run afoul of the rule that says that any list operator
2788 followed by parentheses turns into a function, with all the list
2789 operators arguments found inside the parentheses. See
2790 L<perlop/Terms and List Operators (Leftward)>.
2792 =item In '(?...)', the '(' and '?' must be adjacent in regex;
2793 marked by S<<-- HERE> in m/%s/
2795 (F) The two-character sequence C<"(?"> in this context in a regular
2796 expression pattern should be an indivisible token, with nothing
2797 intervening between the C<"("> and the C<"?">, but you separated them
2800 =item Invalid %s attribute: %s
2802 (F) The indicated attribute for a subroutine or variable was not recognized
2803 by Perl or by a user-supplied handler. See L<attributes>.
2805 =item Invalid %s attributes: %s
2807 (F) The indicated attributes for a subroutine or variable were not
2808 recognized by Perl or by a user-supplied handler. See L<attributes>.
2810 =item Invalid character in charnames alias definition; marked by
2813 (F) You tried to create a custom alias for a character name, with
2814 the C<:alias> option to C<use charnames> and the specified character in
2815 the indicated name isn't valid. See L<charnames/CUSTOM ALIASES>.
2817 =item Invalid \0 character in %s for %s: %s\0%s
2819 (W syscalls) Embedded \0 characters in pathnames or other system call
2820 arguments produce a warning as of 5.20. The parts after the \0 were
2821 formerly ignored by system calls.
2823 =item Invalid character in \N{...}; marked by S<<-- HERE> in \N{%s}
2825 (F) Only certain characters are valid for character names. The
2826 indicated one isn't. See L<charnames/CUSTOM ALIASES>.
2828 =item Invalid conversion in %s: "%s"
2830 (W printf) Perl does not understand the given format conversion. See
2831 L<perlfunc/sprintf>.
2833 =item Invalid escape in the specified encoding in regex; marked by
2834 S<<-- HERE> in m/%s/
2836 (W regexp)(F) The numeric escape (for example C<\xHH>) of value < 256
2837 didn't correspond to a single character through the conversion
2838 from the encoding specified by the encoding pragma.
2839 The escape was replaced with REPLACEMENT CHARACTER (U+FFFD)
2840 instead, except within S<C<(?[ ])>>, where it is a fatal error.
2841 The S<<-- HERE> shows whereabouts in the regular expression the
2842 escape was discovered.
2844 =item Invalid hexadecimal number in \N{U+...}
2846 =item Invalid hexadecimal number in \N{U+...} in regex; marked by
2847 S<<-- HERE> in m/%s/
2849 (F) The character constant represented by C<...> is not a valid hexadecimal
2850 number. Either it is empty, or you tried to use a character other than
2851 0 - 9 or A - F, a - f in a hexadecimal number.
2853 =item Invalid module name %s with -%c option: contains single ':'
2855 (F) The module argument to perl's B<-m> and B<-M> command-line options
2856 cannot contain single colons in the module name, but only in the
2857 arguments after "=". In other words, B<-MFoo::Bar=:baz> is ok, but
2858 B<-MFoo:Bar=baz> is not.
2860 =item Invalid mro name: '%s'
2862 (F) You tried to C<mro::set_mro("classname", "foo")> or C<use mro 'foo'>,
2863 where C<foo> is not a valid method resolution order (MRO). Currently,
2864 the only valid ones supported are C<dfs> and C<c3>, unless you have loaded
2865 a module that is a MRO plugin. See L<mro> and L<perlmroapi>.
2867 =item Invalid negative number (%s) in chr
2869 (W utf8) You passed a negative number to C<chr>. Negative numbers are
2870 not valid character numbers, so it returns the Unicode replacement
2873 =item invalid option -D%c, use -D'' to see choices
2875 (S debugging) Perl was called with invalid debugger flags. Call perl
2876 with the B<-D> option with no flags to see the list of acceptable values.
2877 See also L<perlrun/-Dletters>.
2879 =item Invalid quantifier in {,} in regex; marked by S<<-- HERE> in m/%s/
2881 (F) The pattern looks like a {min,max} quantifier, but the min or max
2882 could not be parsed as a valid number - either it has leading zeroes,
2883 or it represents too big a number to cope with. The S<<-- HERE> shows
2884 where in the regular expression the problem was discovered. See L<perlre>.
2886 =item Invalid [] range "%s" in regex; marked by S<<-- HERE> in m/%s/
2888 (F) The range specified in a character class had a minimum character
2889 greater than the maximum character. One possibility is that you forgot the
2890 C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
2891 up to C<ff>. The S<<-- HERE> shows whereabouts in the regular expression the
2892 problem was discovered. See L<perlre>.
2894 =item Invalid range "%s" in transliteration operator
2896 (F) The range specified in the tr/// or y/// operator had a minimum
2897 character greater than the maximum character. See L<perlop>.
2899 =item Invalid separator character %s in attribute list
2901 (F) Something other than a colon or whitespace was seen between the
2902 elements of an attribute list. If the previous attribute had a
2903 parenthesised parameter list, perhaps that list was terminated too soon.
2906 =item Invalid separator character %s in PerlIO layer specification %s
2908 (W layer) When pushing layers onto the Perl I/O system, something other
2909 than a colon or whitespace was seen between the elements of a layer list.
2910 If the previous attribute had a parenthesised parameter list, perhaps that
2911 list was terminated too soon.
2913 =item Invalid strict version format (%s)
2915 (F) A version number did not meet the "strict" criteria for versions.
2916 A "strict" version number is a positive decimal number (integer or
2917 decimal-fraction) without exponentiation or else a dotted-decimal
2918 v-string with a leading 'v' character and at least three components.
2919 The parenthesized text indicates which criteria were not met.
2920 See the L<version> module for more details on allowed version formats.
2922 =item Invalid type '%s' in %s
2924 (F) The given character is not a valid pack or unpack type.
2925 See L<perlfunc/pack>.
2927 (W) The given character is not a valid pack or unpack type but used to be
2930 =item Invalid version format (%s)
2932 (F) A version number did not meet the "lax" criteria for versions.
2933 A "lax" version number is a positive decimal number (integer or
2934 decimal-fraction) without exponentiation or else a dotted-decimal
2935 v-string. If the v-string has fewer than three components, it
2936 must have a leading 'v' character. Otherwise, the leading 'v' is
2937 optional. Both decimal and dotted-decimal versions may have a
2938 trailing "alpha" component separated by an underscore character
2939 after a fractional or dotted-decimal component. The parenthesized
2940 text indicates which criteria were not met. See the L<version> module
2941 for more details on allowed version formats.
2943 =item Invalid version object
2945 (F) The internal structure of the version object was invalid.
2946 Perhaps the internals were modified directly in some way or
2947 an arbitrary reference was blessed into the "version" class.
2949 =item In '(*VERB...)', the '(' and '*' must be adjacent in regex;
2950 marked by S<<-- HERE> in m/%s/
2952 (F) The two-character sequence C<"(*"> in
2953 this context in a regular expression pattern should be an
2954 indivisible token, with nothing intervening between the C<"(">
2955 and the C<"*">, but you separated them.
2957 =item ioctl is not implemented
2959 (F) Your machine apparently doesn't implement ioctl(), which is pretty
2960 strange for a machine that supports C.
2962 =item ioctl() on unopened %s
2964 (W unopened) You tried ioctl() on a filehandle that was never opened.
2965 Check your control flow and number of arguments.
2967 =item IO layers (like '%s') unavailable
2969 (F) Your Perl has not been configured to have PerlIO, and therefore
2970 you cannot use IO layers. To have PerlIO, Perl must be configured
2973 =item IO::Socket::atmark not implemented on this architecture
2975 (F) Your machine doesn't implement the sockatmark() functionality,
2976 neither as a system call nor an ioctl call (SIOCATMARK).
2978 =item '%s' is an unknown bound type in regex; marked by S<<-- HERE> in m/%s/
2980 (F) You used C<\b{...}> or C<\B{...}> and the C<...> is not known to
2981 Perl. The current valid ones are given in
2982 L<perlrebackslash/\b{}, \b, \B{}, \B>.
2984 =item "%s" is more clearly written simply as "%s" in regex; marked by S<<-- HERE> in m/%s/
2986 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
2988 You specified a character that has the given plainer way of writing it,
2989 and which is also portable to platforms running with different character
2992 =item $* is no longer supported
2994 (D deprecated, syntax) The special variable C<$*>, deprecated in older
2995 perls, has been removed as of 5.10.0 and is no longer supported. In
2996 previous versions of perl the use of C<$*> enabled or disabled multi-line
2997 matching within a string.
2999 Instead of using C<$*> you should use the C</m> (and maybe C</s>) regexp
3000 modifiers. You can enable C</m> for a lexical scope (even a whole file)
3001 with C<use re '/m'>. (In older versions: when C<$*> was set to a true value
3002 then all regular expressions behaved as if they were written using C</m>.)
3004 =item $# is no longer supported
3006 (D deprecated, syntax) The special variable C<$#>, deprecated in older
3007 perls, has been removed as of 5.10.0 and is no longer supported. You
3008 should use the printf/sprintf functions instead.
3010 =item '%s' is not a code reference
3012 (W overload) The second (fourth, sixth, ...) argument of
3013 overload::constant needs to be a code reference. Either
3014 an anonymous subroutine, or a reference to a subroutine.
3016 =item '%s' is not an overloadable type
3018 (W overload) You tried to overload a constant type the overload package is
3021 =item -i used with no filenames on the command line, reading from STDIN
3023 (S inplace) The C<-i> option was passed on the command line, indicating
3024 that the script is intended to edit files in place, but no files were
3025 given. This is usually a mistake, since editing STDIN in place doesn't
3026 make sense, and can be confusing because it can make perl look like
3027 it is hanging when it is really just trying to read from STDIN. You
3028 should either pass a filename to edit, or remove C<-i> from the command
3029 line. See L<perlrun> for more details.
3031 =item Junk on end of regexp in regex m/%s/
3033 (P) The regular expression parser is confused.
3035 =item Label not found for "last %s"
3037 (F) You named a loop to break out of, but you're not currently in a loop
3038 of that name, not even if you count where you were called from. See
3041 =item Label not found for "next %s"
3043 (F) You named a loop to continue, but you're not currently in a loop of
3044 that name, not even if you count where you were called from. See
3047 =item Label not found for "redo %s"
3049 (F) You named a loop to restart, but you're not currently in a loop of
3050 that name, not even if you count where you were called from. See
3053 =item leaving effective %s failed
3055 (F) While under the C<use filetest> pragma, switching the real and
3056 effective uids or gids failed.
3058 =item length/code after end of string in unpack
3060 (F) While unpacking, the string buffer was already used up when an unpack
3061 length/code combination tried to obtain more data. This results in
3062 an undefined value for the length. See L<perlfunc/pack>.
3064 =item length() used on %s (did you mean "scalar(%s)"?)
3066 (W syntax) You used length() on either an array or a hash when you
3067 probably wanted a count of the items.
3069 Array size can be obtained by doing:
3073 The number of items in a hash can be obtained by doing:
3077 =item Lexing code attempted to stuff non-Latin-1 character into Latin-1 input
3079 (F) An extension is attempting to insert text into the current parse
3080 (using L<lex_stuff_pvn|perlapi/lex_stuff_pvn> or similar), but tried to insert a character that
3081 couldn't be part of the current input. This is an inherent pitfall
3082 of the stuffing mechanism, and one of the reasons to avoid it. Where
3083 it is necessary to stuff, stuffing only plain ASCII is recommended.
3085 =item Lexing code internal error (%s)
3087 (F) Lexing code supplied by an extension violated the lexer's API in a
3090 =item listen() on closed socket %s
3092 (W closed) You tried to do a listen on a closed socket. Did you forget
3093 to check the return value of your socket() call? See
3096 =item List form of piped open not implemented
3098 (F) On some platforms, notably Windows, the three-or-more-arguments
3099 form of C<open> does not support pipes, such as C<open($pipe, '|-', @args)>.
3100 Use the two-argument C<open($pipe, '|prog arg1 arg2...')> form instead.
3102 =item %s: loadable library and perl binaries are mismatched (got handshake key %p, needed %p)
3104 (P) A dynamic loading library C<.so> or C<.dll> was being loaded into the
3105 process that was built against a different build of perl than the
3106 said library was compiled against. Reinstalling the XS module will
3107 likely fix this error.
3109 =item Locale '%s' may not work well.%s
3111 (W locale) You are using the named locale, which is a non-UTF-8 one, and
3112 which perl has determined is not fully compatible with what it can
3113 handle. The second C<%s> gives a reason.
3115 By far the most common reason is that the locale has characters in it
3116 that are represented by more than one byte. The only such locales that
3117 Perl can handle are the UTF-8 locales. Most likely the specified locale
3118 is a non-UTF-8 one for an East Asian language such as Chinese or
3119 Japanese. If the locale is a superset of ASCII, the ASCII portion of it
3122 Some essentially obsolete locales that aren't supersets of ASCII, mainly
3123 those in ISO 646 or other 7-bit locales, such as ASMO 449, can also have
3124 problems, depending on what portions of the ASCII character set get
3125 changed by the locale and are also used by the program.
3126 The warning message lists the determinable conflicting characters.
3128 Note that not all incompatibilities are found.
3130 If this happens to you, there's not much you can do except switch to use a
3131 different locale or use L<Encode> to translate from the locale into
3132 UTF-8; if that's impracticable, you have been warned that some things
3135 This message is output once each time a bad locale is switched into
3136 within the scope of C<S<use locale>>, or on the first possibly-affected
3137 operation if the C<S<use locale>> inherits a bad one. It is not raised
3138 for any operations from the L<POSIX> module.
3140 =item localtime(%f) failed
3142 (W overflow) You called C<localtime> with a number that it could not handle:
3143 too large, too small, or NaN. The returned value is C<undef>.
3145 =item localtime(%f) too large
3147 (W overflow) You called C<localtime> with a number that was larger
3148 than it can reliably handle and C<localtime> probably returned the
3149 wrong date. This warning is also triggered with NaN (the special
3150 not-a-number value).
3152 =item localtime(%f) too small
3154 (W overflow) You called C<localtime> with a number that was smaller
3155 than it can reliably handle and C<localtime> probably returned the
3158 =item Lookbehind longer than %d not implemented in regex m/%s/
3160 (F) There is currently a limit on the length of string which lookbehind can
3161 handle. This restriction may be eased in a future release.
3163 =item Lost precision when %s %f by 1
3165 (W imprecision) The value you attempted to increment or decrement by one
3166 is too large for the underlying floating point representation to store
3167 accurately, hence the target of C<++> or C<--> is unchanged. Perl issues this
3168 warning because it has already switched from integers to floating point
3169 when values are too large for integers, and now even floating point is
3170 insufficient. You may wish to switch to using L<Math::BigInt> explicitly.
3172 =item lstat() on filehandle%s
3174 (W io) You tried to do an lstat on a filehandle. What did you mean
3175 by that? lstat() makes sense only on filenames. (Perl did a fstat()
3176 instead on the filehandle.)
3178 =item lvalue attribute %s already-defined subroutine
3180 (W misc) Although L<attributes.pm|attributes> allows this, turning the lvalue
3181 attribute on or off on a Perl subroutine that is already defined
3182 does not always work properly. It may or may not do what you
3183 want, depending on what code is inside the subroutine, with exact
3184 details subject to change between Perl versions. Only do this
3185 if you really know what you are doing.
3187 =item lvalue attribute ignored after the subroutine has been defined
3189 (W misc) Using the C<:lvalue> declarative syntax to make a Perl
3190 subroutine an lvalue subroutine after it has been defined is
3191 not permitted. To make the subroutine an lvalue subroutine,
3192 add the lvalue attribute to the definition, or put the C<sub
3193 foo :lvalue;> declaration before the definition.
3195 See also L<attributes.pm|attributes>.
3197 =item Magical list constants are not supported
3199 (F) You assigned a magical array to a stash element, and then tried
3200 to use the subroutine from the same slot. You are asking Perl to do
3201 something it cannot do, details subject to change between Perl versions.
3203 =item Malformed integer in [] in pack
3205 (F) Between the brackets enclosing a numeric repeat count only digits
3206 are permitted. See L<perlfunc/pack>.
3208 =item Malformed integer in [] in unpack
3210 (F) Between the brackets enclosing a numeric repeat count only digits
3211 are permitted. See L<perlfunc/pack>.
3213 =item Malformed PERLLIB_PREFIX
3215 (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
3222 with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
3223 a builtin library search path, prefix2 is substituted. The error may
3224 appear if components are not found, or are too long. See
3225 "PERLLIB_PREFIX" in L<perlos2>.
3227 =item Malformed prototype for %s: %s
3229 (F) You tried to use a function with a malformed prototype. The
3230 syntax of function prototypes is given a brief compile-time check for
3231 obvious errors like invalid characters. A more rigorous check is run
3232 when the function is called.
3233 Perhaps the function's author was trying to write a subroutine signature
3234 but didn't enable that feature first (C<use feature 'signatures'>),
3235 so the signature was instead interpreted as a bad prototype.
3237 =item Malformed UTF-8 character (%s)
3239 (S utf8)(F) Perl detected a string that didn't comply with UTF-8
3240 encoding rules, even though it had the UTF8 flag on.
3242 One possible cause is that you set the UTF8 flag yourself for data that
3243 you thought to be in UTF-8 but it wasn't (it was for example legacy
3244 8-bit data). To guard against this, you can use Encode::decode_utf8.
3246 If you use the C<:encoding(UTF-8)> PerlIO layer for input, invalid byte
3247 sequences are handled gracefully, but if you use C<:utf8>, the flag is
3248 set without validating the data, possibly resulting in this error
3251 See also L<Encode/"Handling Malformed Data">.
3253 =item Malformed UTF-8 character immediately after '%s'
3255 (F) You said C<use utf8>, but the program file doesn't comply with UTF-8
3256 encoding rules. The message prints out the properly encoded characters
3257 just before the first bad one. If C<utf8> warnings are enabled, a
3258 warning is generated that gives more details about the type of
3261 =item Malformed UTF-8 returned by \N{%s} immediately after '%s'
3263 (F) The charnames handler returned malformed UTF-8.
3265 =item Malformed UTF-8 string in '%c' format in unpack
3267 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3268 rules and perl was unable to guess how to make more progress.
3270 =item Malformed UTF-8 string in pack
3272 (F) You tried to pack something that didn't comply with UTF-8 encoding
3273 rules and perl was unable to guess how to make more progress.
3275 =item Malformed UTF-8 string in unpack
3277 (F) You tried to unpack something that didn't comply with UTF-8 encoding
3278 rules and perl was unable to guess how to make more progress.
3280 =item Malformed UTF-16 surrogate
3282 (F) Perl thought it was reading UTF-16 encoded character data but while
3283 doing it Perl met a malformed Unicode surrogate.
3285 =item Mandatory parameter follows optional parameter
3287 (F) In a subroutine signature, you wrote something like "$a = undef,
3288 $b", making an earlier parameter optional and a later one mandatory.
3289 Parameters are filled from left to right, so it's impossible for the
3290 caller to omit an earlier one and pass a later one. If you want to act
3291 as if the parameters are filled from right to left, declare the rightmost
3292 optional and then shuffle the parameters around in the subroutine's body.
3294 =item Matched non-Unicode code point 0x%X against Unicode property; may
3297 (S non_unicode) Perl allows strings to contain a superset of
3298 Unicode code points; each code point may be as large as what is storable
3299 in an unsigned integer on your system, but these may not be accepted by
3300 other languages/systems. This message occurs when you matched a string
3301 containing such a code point against a regular expression pattern, and
3302 the code point was matched against a Unicode property, C<\p{...}> or
3303 C<\P{...}>. Unicode properties are only defined on Unicode code points,
3304 so the result of this match is undefined by Unicode, but Perl (starting
3305 in v5.20) treats non-Unicode code points as if they were typical
3306 unassigned Unicode ones, and matched this one accordingly. Whether a
3307 given property matches these code points or not is specified in
3308 L<perluniprops/Properties accessible through \p{} and \P{}>.
3310 This message is suppressed (unless it has been made fatal) if it is
3311 immaterial to the results of the match if the code point is Unicode or
3312 not. For example, the property C<\p{ASCII_Hex_Digit}> only can match
3313 the 22 characters C<[0-9A-Fa-f]>, so obviously all other code points,
3314 Unicode or not, won't match it. (And C<\P{ASCII_Hex_Digit}> will match
3315 every code point except these 22.)
3317 Getting this message indicates that the outcome of the match arguably
3318 should have been the opposite of what actually happened. If you think
3319 that is the case, you may wish to make the C<non_unicode> warnings
3320 category fatal; if you agree with Perl's decision, you may wish to turn
3323 See L<perlunicode/Beyond Unicode code points> for more information.
3325 =item %s matches null string many times in regex; marked by S<<-- HERE> in
3328 (W regexp) The pattern you've specified would be an infinite loop if the
3329 regular expression engine didn't specifically check for that. The S<<-- HERE>
3330 shows whereabouts in the regular expression the problem was discovered.
3333 =item Maximal count of pending signals (%u) exceeded
3335 (F) Perl aborted due to too high a number of signals pending. This
3336 usually indicates that your operating system tried to deliver signals
3337 too fast (with a very high priority), starving the perl process from
3338 resources it would need to reach a point where it can process signals
3339 safely. (See L<perlipc/"Deferred Signals (Safe Signals)">.)
3341 =item "%s" may clash with future reserved word
3343 (W) This warning may be due to running a perl5 script through a perl4
3344 interpreter, especially if the word that is being warned about is
3347 =item '%' may not be used in pack
3349 (F) You can't pack a string by supplying a checksum, because the
3350 checksumming process loses information, and you can't go the other way.
3351 See L<perlfunc/unpack>.
3353 =item Method for operation %s not found in package %s during blessing
3355 (F) An attempt was made to specify an entry in an overloading table that
3356 doesn't resolve to a valid subroutine. See L<overload>.
3358 =item Method %s not permitted
3362 =item Might be a runaway multi-line %s string starting on line %d
3364 (S) An advisory indicating that the previous error may have been caused
3365 by a missing delimiter on a string or pattern, because it eventually
3366 ended earlier on the current line.
3368 =item Misplaced _ in number
3370 (W syntax) An underscore (underbar) in a numeric constant did not
3371 separate two digits.
3373 =item Missing argument in %s
3375 (W missing) You called a function with fewer arguments than other
3376 arguments you supplied indicated would be needed.
3378 Currently only emitted when a printf-type format required more
3379 arguments than were supplied, but might be used in the future for
3380 other cases where we can statically determine that arguments to
3381 functions are missing, e.g. for the L<perlfunc/pack> function.
3383 =item Missing argument to -%c
3385 (F) The argument to the indicated command line switch must follow
3386 immediately after the switch, without intervening spaces.
3388 =item Missing braces on \N{}
3390 =item Missing braces on \N{} in regex; marked by S<<-- HERE> in m/%s/
3392 (F) Wrong syntax of character name literal C<\N{charname}> within
3393 double-quotish context. This can also happen when there is a space
3394 (or comment) between the C<\N> and the C<{> in a regex with the C</x> modifier.
3395 This modifier does not change the requirement that the brace immediately
3398 =item Missing braces on \o{}
3400 (F) A C<\o> must be followed immediately by a C<{> in double-quotish context.
3402 =item Missing comma after first argument to %s function
3404 (F) While certain functions allow you to specify a filehandle or an
3405 "indirect object" before the argument list, this ain't one of them.
3407 =item Missing command in piped open
3409 (W pipe) You used the C<open(FH, "| command")> or
3410 C<open(FH, "command |")> construction, but the command was missing or
3413 =item Missing control char name in \c
3415 (F) A double-quoted string ended with "\c", without the required control
3418 =item Missing ']' in prototype for %s : %s
3420 (W illegalproto) A grouping was started with C<[> but never closed with C<]>.
3422 =item Missing name in "%s sub"
3424 (F) The syntax for lexically scoped subroutines requires that
3425 they have a name with which they can be found.
3427 =item Missing $ on loop variable
3429 (F) Apparently you've been programming in B<csh> too much. Variables
3430 are always mentioned with the $ in Perl, unlike in the shells, where it
3431 can vary from one line to the next.
3433 =item (Missing operator before %s?)
3435 (S syntax) This is an educated guess made in conjunction with the message
3436 "%s found where operator expected". Often the missing operator is a comma.
3438 =item Missing or undefined argument to require
3440 (F) You tried to call require with no argument or with an undefined
3441 value as an argument. Require expects either a package name or a
3442 file-specification as an argument. See L<perlfunc/require>.
3444 =item Missing right brace on \%c{} in regex; marked by S<<-- HERE> in m/%s/
3446 (F) Missing right brace in C<\x{...}>, C<\p{...}>, C<\P{...}>, or C<\N{...}>.
3448 =item Missing right brace on \N{}
3450 =item Missing right brace on \N{} or unescaped left brace after \N
3452 (F) C<\N> has two meanings.
3454 The traditional one has it followed by a name enclosed in braces,
3455 meaning the character (or sequence of characters) given by that
3456 name. Thus C<\N{ASTERISK}> is another way of writing C<*>, valid in both
3457 double-quoted strings and regular expression patterns. In patterns,
3458 it doesn't have the meaning an unescaped C<*> does.
3460 Starting in Perl 5.12.0, C<\N> also can have an additional meaning (only)
3461 in patterns, namely to match a non-newline character. (This is short
3462 for C<[^\n]>, and like C<.> but is not affected by the C</s> regex modifier.)
3464 This can lead to some ambiguities. When C<\N> is not followed immediately
3465 by a left brace, Perl assumes the C<[^\n]> meaning. Also, if the braces
3466 form a valid quantifier such as C<\N{3}> or C<\N{5,}>, Perl assumes that this
3467 means to match the given quantity of non-newlines (in these examples,
3468 3; and 5 or more, respectively). In all other case, where there is a
3469 C<\N{> and a matching C<}>, Perl assumes that a character name is desired.
3471 However, if there is no matching C<}>, Perl doesn't know if it was
3472 mistakenly omitted, or if C<[^\n]{> was desired, and raises this error.
3473 If you meant the former, add the right brace; if you meant the latter,
3474 escape the brace with a backslash, like so: C<\N\{>
3476 =item Missing right curly or square bracket
3478 (F) The lexer counted more opening curly or square brackets than closing
3479 ones. As a general rule, you'll find it's missing near the place you
3482 =item (Missing semicolon on previous line?)
3484 (S syntax) This is an educated guess made in conjunction with the message
3485 "%s found where operator expected". Don't automatically put a semicolon on
3486 the previous line just because you saw this message.
3488 =item Modification of a read-only value attempted
3490 (F) You tried, directly or indirectly, to change the value of a
3491 constant. You didn't, of course, try "2 = 1", because the compiler
3492 catches that. But an easy way to do the same thing is:
3494 sub mod { $_[0] = 1 }
3497 Another way is to assign to a substr() that's off the end of the string.
3499 Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
3500 is aliased to a constant in the look I<LIST>:
3503 foreach my $n ($x, 2) {
3504 $n *= 2; # modifies the $x, but fails on attempt to
3507 =item Modification of non-creatable array value attempted, %s
3509 (F) You tried to make an array value spring into existence, and the
3510 subscript was probably negative, even counting from end of the array
3513 =item Modification of non-creatable hash value attempted, %s
3515 (P) You tried to make a hash value spring into existence, and it
3516 couldn't be created for some peculiar reason.
3518 =item Module name must be constant
3520 (F) Only a bare module name is allowed as the first argument to a "use".
3522 =item Module name required with -%c option
3524 (F) The C<-M> or C<-m> options say that Perl should load some module, but
3525 you omitted the name of the module. Consult L<perlrun> for full details
3526 about C<-M> and C<-m>.
3528 =item More than one argument to '%s' open
3530 (F) The C<open> function has been asked to open multiple files. This
3531 can happen if you are trying to open a pipe to a command that takes a
3532 list of arguments, but have forgotten to specify a piped open mode.
3533 See L<perlfunc/open> for details.
3535 =item mprotect for COW string %p %u failed with %d
3537 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3538 L<perlguts/"Copy on Write">), but a shared string buffer
3539 could not be made read-only.
3541 =item mprotect for %p %u failed with %d
3543 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see L<perlhacktips>),
3544 but an op tree could not be made read-only.
3546 =item mprotect RW for COW string %p %u failed with %d
3548 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_COW (see
3549 L<perlguts/"Copy on Write">), but a read-only shared string
3550 buffer could not be made mutable.
3552 =item mprotect RW for %p %u failed with %d
3554 (S) You compiled perl with B<-D>PERL_DEBUG_READONLY_OPS (see
3555 L<perlhacktips>), but a read-only op tree could not be made
3556 mutable before freeing the ops.
3558 =item msg%s not implemented
3560 (F) You don't have System V message IPC on your system.
3562 =item Multidimensional syntax %s not supported
3564 (W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
3565 They're written like C<$foo[1][2][3]>, as in C.
3567 =item '/' must follow a numeric type in unpack
3569 (F) You had an unpack template that contained a '/', but this did not
3570 follow some unpack specification producing a numeric value.
3571 See L<perlfunc/pack>.
3573 =item %s must not be a named sequence in transliteration operator
3575 (F) Transliteration (C<tr///> and C<y///>) transliterates individual
3576 characters. But a named sequence by definition is more than an
3577 individual charater, and hence doing this operation on it doesn't make
3580 =item "my sub" not yet implemented
3582 (F) Lexically scoped subroutines are not yet implemented. Don't try
3585 =item "my" subroutine %s can't be in a package
3587 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
3588 sense to try to declare one with a package qualifier on the front.
3590 =item "my %s" used in sort comparison
3592 (W syntax) The package variables $a and $b are used for sort comparisons.
3593 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
3594 sort comparison block, and the variable had earlier been declared as a
3595 lexical variable. Either qualify the sort variable with the package
3596 name, or rename the lexical variable.
3598 =item "my" variable %s can't be in a package
3600 (F) Lexically scoped variables aren't in a package, so it doesn't make
3601 sense to try to declare one with a package qualifier on the front. Use
3602 local() if you want to localize a package variable.
3604 =item Name "%s::%s" used only once: possible typo
3606 (W once) Typographical errors often show up as unique variable
3607 names. If you had a good reason for having a unique name, then
3608 just mention it again somehow to suppress the message. The C<our>
3609 declaration is also provided for this purpose.
3611 NOTE: This warning detects package symbols that have been used
3612 only once. This means lexical variables will never trigger this
3613 warning. It also means that all of the package variables $c, @c,
3614 %c, as well as *c, &c, sub c{}, c(), and c (the filehandle or
3615 format) are considered the same; if a program uses $c only once
3616 but also uses any of the others it will not trigger this warning.
3617 Symbols beginning with an underscore and symbols using special
3618 identifiers (q.v. L<perldata>) are exempt from this warning.
3620 =item Need exactly 3 octal digits in regex; marked by S<<-- HERE> in m/%s/
3622 (F) Within S<C<(?[ ])>>, all constants interpreted as octal need to be
3623 exactly 3 digits long. This helps catch some ambiguities. If your
3624 constant is too short, add leading zeros, like
3626 (?[ [ \078 ] ]) # Syntax error!
3627 (?[ [ \0078 ] ]) # Works
3628 (?[ [ \007 8 ] ]) # Clearer
3630 The maximum number this construct can express is C<\777>. If you
3631 need a larger one, you need to use L<\o{}|perlrebackslash/Octal escapes> instead. If you meant
3632 two separate things, you need to separate them:
3634 (?[ [ \7776 ] ]) # Syntax error!
3635 (?[ [ \o{7776} ] ]) # One meaning
3636 (?[ [ \777 6 ] ]) # Another meaning
3637 (?[ [ \777 \006 ] ]) # Still another
3639 =item Negative '/' count in unpack
3641 (F) The length count obtained from a length/code unpack operation was
3642 negative. See L<perlfunc/pack>.
3644 =item Negative length
3646 (F) You tried to do a read/write/send/recv operation with a buffer
3647 length that is less than 0. This is difficult to imagine.
3649 =item Negative offset to vec in lvalue context
3651 (F) When C<vec> is called in an lvalue context, the second argument must be
3652 greater than or equal to zero.
3654 =item Negative repeat count does nothing
3656 (W numeric) You tried to execute the
3657 L<C<x>|perlop/Multiplicative Operators> repetition operator fewer than 0
3658 times, which doesn't make sense.
3660 =item Nested quantifiers in regex; marked by S<<-- HERE> in m/%s/
3662 (F) You can't quantify a quantifier without intervening parentheses.
3663 So things like ** or +* or ?* are illegal. The S<<-- HERE> shows
3664 whereabouts in the regular expression the problem was discovered.
3666 Note that the minimal matching quantifiers, C<*?>, C<+?>, and
3667 C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
3669 =item %s never introduced
3671 (S internal) The symbol in question was declared but somehow went out of
3672 scope before it could possibly have been used.
3674 =item next::method/next::can/maybe::next::method cannot find enclosing method
3676 (F) C<next::method> needs to be called within the context of a
3677 real method in a real package, and it could not find such a context.
3680 =item \N in a character class must be a named character: \N{...} in regex;
3681 marked by S<<-- HERE> in m/%s/
3683 (F) The new (as of Perl 5.12) meaning of C<\N> as C<[^\n]> is not valid in a
3684 bracketed character class, for the same reason that C<.> in a character
3685 class loses its specialness: it matches almost everything, which is
3686 probably not what you want.
3688 =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/
3690 (F) Named Unicode character escapes (C<\N{...}>) may return a
3691 multi-character sequence. Even though a character class is
3692 supposed to match just one character of input, perl will match the
3693 whole thing correctly, except when the class is inverted (C<[^...]>),
3694 or the escape is the beginning or final end point of a range. The
3695 mathematically logical behavior for what matches when inverting
3696 is very different from what people expect, so we have decided to
3697 forbid it. Similarly unclear is what should be generated when the
3698 C<\N{...}> is used as one of the end points of the range, such as in
3700 [\x{41}-\N{ARABIC SEQUENCE YEH WITH HAMZA ABOVE WITH AE}]
3702 What is meant here is unclear, as the C<\N{...}> escape is a sequence
3703 of code points, so this is made an error.
3705 =item \N{NAME} must be resolved by the lexer in regex; marked by
3706 S<<-- HERE> in m/%s/
3708 (F) When compiling a regex pattern, an unresolved named character or
3709 sequence was encountered. This can happen in any of several ways that
3710 bypass the lexer, such as using single-quotish context, or an extra
3711 backslash in double-quotish:
3713 $re = '\N{SPACE}'; # Wrong!
3714 $re = "\\N{SPACE}"; # Wrong!
3717 Instead, use double-quotes with a single backslash:
3719 $re = "\N{SPACE}"; # ok
3722 The lexer can be bypassed as well by creating the pattern from smaller
3726 /${re}{SPACE}/; # Wrong!
3728 It's not a good idea to split a construct in the middle like this, and
3729 it doesn't work here. Instead use the solution above.
3731 Finally, the message also can happen under the C</x> regex modifier when the
3732 C<\N> is separated by spaces from the C<{>, in which case, remove the spaces.
3734 /\N {SPACE}/x; # Wrong!
3737 =item No %s allowed while running setuid
3739 (F) Certain operations are deemed to be too insecure for a setuid or
3740 setgid script to even be allowed to attempt. Generally speaking there
3741 will be another way to do what you want that is, if not secure, at least
3742 securable. See L<perlsec>.
3744 =item NO-BREAK SPACE in a charnames alias definition is deprecated
3746 (D deprecated) You defined a character name which contained a no-break
3747 space character. Change it to a regular space. Usually these names are
3748 defined in the C<:alias> import argument to C<use charnames>, but they
3749 could be defined by a translator installed into C<$^H{charnames}>. See
3750 L<charnames/CUSTOM ALIASES>.
3752 =item No code specified for -%c
3754 (F) Perl's B<-e> and B<-E> command-line options require an argument. If
3755 you want to run an empty program, pass the empty string as a separate
3756 argument or run a program consisting of a single 0 or 1:
3762 =item No comma allowed after %s
3764 (F) A list operator that has a filehandle or "indirect object" is
3765 not allowed to have a comma between that and the following arguments.
3766 Otherwise it'd be just another one of the arguments.
3768 One possible cause for this is that you expected to have imported
3769 a constant to your name space with B<use> or B<import> while no such
3770 importing took place, it may for example be that your operating
3771 system does not support that particular constant. Hopefully you did
3772 use an explicit import list for the constants you expect to see;
3773 please see L<perlfunc/use> and L<perlfunc/import>. While an
3774 explicit import list would probably have caught this error earlier
3775 it naturally does not remedy the fact that your operating system
3776 still does not support that constant. Maybe you have a typo in
3777 the constants of the symbol import list of B<use> or B<import> or in the
3778 constant name at the line where this error was triggered?
3780 =item No command into which to pipe on command line
3782 (F) An error peculiar to VMS. Perl handles its own command line
3783 redirection, and found a '|' at the end of the command line, so it
3784 doesn't know where you want to pipe the output from this command.
3786 =item No DB::DB routine defined
3788 (F) The currently executing code was compiled with the B<-d> switch, but
3789 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3790 module) didn't define a routine to be called at the beginning of each
3793 =item No dbm on this machine
3795 (P) This is counted as an internal error, because every machine should
3796 supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
3798 =item No DB::sub routine defined
3800 (F) The currently executing code was compiled with the B<-d> switch, but
3801 for some reason the current debugger (e.g. F<perl5db.pl> or a C<Devel::>
3802 module) didn't define a C<DB::sub> routine to be called at the beginning
3803 of each ordinary subroutine call.
3805 =item No directory specified for -I
3807 (F) The B<-I> command-line switch requires a directory name as part of the
3808 I<same> argument. Use B<-Ilib>, for instance. B<-I lib> won't work.
3810 =item No error file after 2> or 2>> on command line
3812 (F) An error peculiar to VMS. Perl handles its own command line
3813 redirection, and found a '2>' or a '2>>' on the command line, but can't
3814 find the name of the file to which to write data destined for stderr.
3816 =item No group ending character '%c' found in template
3818 (F) A pack or unpack template has an opening '(' or '[' without its
3819 matching counterpart. See L<perlfunc/pack>.
3821 =item No input file after < on command line
3823 (F) An error peculiar to VMS. Perl handles its own command line
3824 redirection, and found a '<' on the command line, but can't find the
3825 name of the file from which to read data for stdin.
3827 =item No next::method '%s' found for %s
3829 (F) C<next::method> found no further instances of this method name
3830 in the remaining packages of the MRO of this class. If you don't want
3831 it throwing an exception, use C<maybe::next::method>
3832 or C<next::can>. See L<mro>.
3834 =item Non-finite repeat count does nothing
3836 (W numeric) You tried to execute the
3837 L<C<x>|perlop/Multiplicative Operators> repetition operator C<Inf> (or
3838 C<-Inf>) or C<NaN> times, which doesn't make sense.
3840 =item Non-hex character in regex; marked by S<<-- HERE> in m/%s/
3842 (F) In a regular expression, there was a non-hexadecimal character where
3843 a hex one was expected, like
3848 =item Non-octal character in regex; marked by S<<-- HERE> in m/%s/
3850 (F) In a regular expression, there was a non-octal character where
3851 an octal one was expected, like
3855 =item Non-octal character '%c'. Resolved as "%s"
3857 (W digit) In parsing an octal numeric constant, a character was
3858 unexpectedly encountered that isn't octal. The resulting value
3861 =item "no" not allowed in expression
3863 (F) The "no" keyword is recognized and executed at compile time, and
3864 returns no useful value. See L<perlmod>.
3866 =item Non-string passed as bitmask
3868 (W misc) A number has been passed as a bitmask argument to select().
3869 Use the vec() function to construct the file descriptor bitmasks for
3870 select. See L<perlfunc/select>.
3872 =item No output file after > on command line
3874 (F) An error peculiar to VMS. Perl handles its own command line
3875 redirection, and found a lone '>' at the end of the command line, so it
3876 doesn't know where you wanted to redirect stdout.
3878 =item No output file after > or >> on command line
3880 (F) An error peculiar to VMS. Perl handles its own command line
3881 redirection, and found a '>' or a '>>' on the command line, but can't
3882 find the name of the file to which to write data destined for stdout.
3884 =item No package name allowed for variable %s in "our"
3886 (F) Fully qualified variable names are not allowed in "our"
3887 declarations, because that doesn't make much sense under existing
3888 rules. Such syntax is reserved for future extensions.
3890 =item No Perl script found in input
3892 (F) You called C<perl -x>, but no line was found in the file beginning
3893 with #! and containing the word "perl".
3895 =item No setregid available
3897 (F) Configure didn't find anything resembling the setregid() call for
3900 =item No setreuid available
3902 (F) Configure didn't find anything resembling the setreuid() call for
3905 =item No such class %s
3907 (F) You provided a class qualifier in a "my", "our" or "state"
3908 declaration, but this class doesn't exist at this point in your program.
3910 =item No such class field "%s" in variable %s of type %s
3912 (F) You tried to access a key from a hash through the indicated typed
3913 variable but that key is not allowed by the package of the same type.
3914 The indicated package has restricted the set of allowed keys using the
3917 =item No such hook: %s
3919 (F) You specified a signal hook that was not recognized by Perl.
3920 Currently, Perl accepts C<__DIE__> and C<__WARN__> as valid signal hooks.
3922 =item No such pipe open
3924 (P) An error peculiar to VMS. The internal routine my_pclose() tried to
3925 close a pipe which hadn't been opened. This should have been caught
3926 earlier as an attempt to close an unopened filehandle.
3928 =item No such signal: SIG%s
3930 (W signal) You specified a signal name as a subscript to %SIG that was
3931 not recognized. Say C<kill -l> in your shell to see the valid signal
3932 names on your system.
3934 =item Not a CODE reference
3936 (F) Perl was trying to evaluate a reference to a code value (that is, a
3937 subroutine), but found a reference to something else instead. You can
3938 use the ref() function to find out what kind of ref it really was. See
3941 =item Not a GLOB reference
3943 (F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
3944 symbol table entry that looks like C<*foo>), but found a reference to
3945 something else instead. You can use the ref() function to find out what
3946 kind of ref it really was. See L<perlref>.
3948 =item Not a HASH reference
3950 (F) Perl was trying to evaluate a reference to a hash value, but found a
3951 reference to something else instead. You can use the ref() function to
3952 find out what kind of ref it really was. See L<perlref>.
3954 =item Not an ARRAY reference
3956 (F) Perl was trying to evaluate a reference to an array value, but found
3957 a reference to something else instead. You can use the ref() function
3958 to find out what kind of ref it really was. See L<perlref>.
3960 =item Not an unblessed ARRAY reference
3962 (F) You passed a reference to a blessed array to C<push>, C<shift> or
3963 another array function. These only accept unblessed array references
3964 or arrays beginning explicitly with C<@>.
3966 =item Not a SCALAR reference
3968 (F) Perl was trying to evaluate a reference to a scalar value, but found
3969 a reference to something else instead. You can use the ref() function
3970 to find out what kind of ref it really was. See L<perlref>.
3972 =item Not a subroutine reference
3974 (F) Perl was trying to evaluate a reference to a code value (that is, a
3975 subroutine), but found a reference to something else instead. You can
3976 use the ref() function to find out what kind of ref it really was. See
3979 =item Not a subroutine reference in overload table
3981 (F) An attempt was made to specify an entry in an overloading table that
3982 doesn't somehow point to a valid subroutine. See L<overload>.
3984 =item Not enough arguments for %s
3986 (F) The function requires more arguments than you specified.
3988 =item Not enough format arguments
3990 (W syntax) A format specified more picture fields than the next line
3991 supplied. See L<perlform>.
3995 (A) You've accidentally run your script through the Bourne shell instead
3996 of Perl. Check the #! line, or manually feed your script into Perl
3999 =item (?[...]) not valid in locale in regex; marked by S<<-- HERE> in m/%s/
4001 (F) C<(?[...])> cannot be used within the scope of a C<S<use locale>> or with
4002 an C</l> regular expression modifier, as that would require deferring
4003 to run-time the calculation of what it should evaluate to, and it is
4004 regex compile-time only.
4006 =item no UTC offset information; assuming local time is UTC
4008 (S) A warning peculiar to VMS. Perl was unable to find the local
4009 timezone offset, so it's assuming that local system time is equivalent
4010 to UTC. If it's not, define the logical name
4011 F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
4012 need to be added to UTC to get local time.
4014 =item NULL OP IN RUN
4016 (S debugging) Some internal routine called run() with a null opcode
4019 =item Null picture in formline
4021 (F) The first argument to formline must be a valid format picture
4022 specification. It was found to be empty, which probably means you
4023 supplied it an uninitialized value. See L<perlform>.
4027 (P) An attempt was made to realloc NULL.
4029 =item NULL regexp argument
4031 (P) The internal pattern matching routines blew it big time.
4033 =item NULL regexp parameter
4035 (P) The internal pattern matching routines are out of their gourd.
4037 =item Number too long
4039 (F) Perl limits the representation of decimal numbers in programs to
4040 about 250 characters. You've exceeded that length. Future
4041 versions of Perl are likely to eliminate this arbitrary limitation. In
4042 the meantime, try using scientific notation (e.g. "1e6" instead of
4045 =item Number with no digits
4047 (F) Perl was looking for a number but found nothing that looked like
4048 a number. This happens, for example with C<\o{}>, with no number between
4051 =item Octal number > 037777777777 non-portable
4053 (W portable) The octal number you specified is larger than 2**32-1
4054 (4294967295) and therefore non-portable between systems. See
4055 L<perlport> for more on portability concerns.
4057 =item Odd name/value argument for subroutine
4059 (F) A subroutine using a slurpy hash parameter in its signature
4060 received an odd number of arguments to populate the hash. It requires
4061 the arguments to be paired, with the same number of keys as values.
4062 The caller of the subroutine is presumably at fault. Inconveniently,
4063 this error will be reported at the location of the subroutine, not that
4066 =item Odd number of arguments for overload::constant
4068 (W overload) The call to overload::constant contained an odd number of
4069 arguments. The arguments should come in pairs.
4071 =item Odd number of elements in anonymous hash
4073 (W misc) You specified an odd number of elements to initialize a hash,
4074 which is odd, because hashes come in key/value pairs.
4076 =item Odd number of elements in hash assignment
4078 (W misc) You specified an odd number of elements to initialize a hash,
4079 which is odd, because hashes come in key/value pairs.
4081 =item Offset outside string
4083 (F)(W layer) You tried to do a read/write/send/recv/seek operation
4084 with an offset pointing outside the buffer. This is difficult to
4085 imagine. The sole exceptions to this are that zero padding will
4086 take place when going past the end of the string when either
4087 C<sysread()>ing a file, or when seeking past the end of a scalar opened
4088 for I/O (in anticipation of future reads and to imitate the behavior
4091 =item %s() on unopened %s
4093 (W unopened) An I/O operation was attempted on a filehandle that was
4094 never initialized. You need to do an open(), a sysopen(), or a socket()
4095 call, or call a constructor from the FileHandle package.
4097 =item -%s on unopened filehandle %s
4099 (W unopened) You tried to invoke a file test operator on a filehandle
4100 that isn't open. Check your control flow. See also L<perlfunc/-X>.
4104 (S internal) An internal warning that the grammar is screwed up.
4108 (S internal) An internal warning that the grammar is screwed up.
4110 =item Opening dirhandle %s also as a file
4112 (D io, deprecated) You used open() to associate a filehandle to
4113 a symbol (glob or scalar) that already holds a dirhandle.
4114 Although legal, this idiom might render your code confusing
4117 =item Opening filehandle %s also as a directory
4119 (D io, deprecated) You used opendir() to associate a dirhandle to
4120 a symbol (glob or scalar) that already holds a filehandle.
4121 Although legal, this idiom might render your code confusing
4124 =item Operand with no preceding operator in regex; marked by S<<-- HERE> in
4127 (F) You wrote something like
4129 (?[ \p{Digit} \p{Thai} ])
4131 There are two operands, but no operator giving how you want to combine
4134 =item Operation "%s": no method found, %s
4136 (F) An attempt was made to perform an overloaded operation for which no
4137 handler was defined. While some handlers can be autogenerated in terms
4138 of other handlers, there is no default handler for any operation, unless
4139 the C<fallback> overloading key is specified to be true. See L<overload>.
4141 =item Operation "%s" returns its argument for non-Unicode code point 0x%X
4143 (S non_unicode) You performed an operation requiring Unicode rules
4144 on a code point that is not in Unicode, so what it should do is not
4145 defined. Perl has chosen to have it do nothing, and warn you.
4147 If the operation shown is "ToFold", it means that case-insensitive
4148 matching in a regular expression was done on the code point.
4150 If you know what you are doing you can turn off this warning by
4151 C<no warnings 'non_unicode';>.
4153 =item Operation "%s" returns its argument for UTF-16 surrogate U+%X
4155 (S surrogate) You performed an operation requiring Unicode
4156 rules on a Unicode surrogate. Unicode frowns upon the use
4157 of surrogates for anything but storing strings in UTF-16, but
4158 rules are (reluctantly) defined for the surrogates, and
4159 they are to do nothing for this operation. Because the use of
4160 surrogates can be dangerous, Perl warns.
4162 If the operation shown is "ToFold", it means that case-insensitive
4163 matching in a regular expression was done on the code point.
4165 If you know what you are doing you can turn off this warning by
4166 C<no warnings 'surrogate';>.
4168 =item Operator or semicolon missing before %s
4170 (S ambiguous) You used a variable or subroutine call where the parser
4171 was expecting an operator. The parser has assumed you really meant to
4172 use an operator, but this is highly likely to be incorrect. For
4173 example, if you say "*foo *foo" it will be interpreted as if you said
4176 =item Optional parameter lacks default expression
4178 (F) In a subroutine signature, you wrote something like "$a =", making a
4179 named optional parameter without a default value. A nameless optional
4180 parameter is permitted to have no default value, but a named one must
4181 have a specific default. You probably want "$a = undef".
4183 =item "our" variable %s redeclared
4185 (W misc) You seem to have already declared the same global once before
4186 in the current lexical scope.
4188 =item Out of memory!
4190 (X) The malloc() function returned 0, indicating there was insufficient
4191 remaining memory (or virtual memory) to satisfy the request. Perl has
4192 no option but to exit immediately.
4194 At least in Unix you may be able to get past this by increasing your
4195 process datasize limits: in csh/tcsh use C<limit> and
4196 C<limit datasize n> (where C<n> is the number of kilobytes) to check
4197 the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
4198 and C<ulimit -d n>, respectively.
4200 =item Out of memory during %s extend
4202 (X) An attempt was made to extend an array, a list, or a string beyond
4203 the largest possible memory allocation.
4205 =item Out of memory during "large" request for %s
4207 (F) The malloc() function returned 0, indicating there was insufficient
4208 remaining memory (or virtual memory) to satisfy the request. However,
4209 the request was judged large enough (compile-time default is 64K), so a
4210 possibility to shut down by trapping this error is granted.
4212 =item Out of memory during request for %s
4214 (X)(F) The malloc() function returned 0, indicating there was
4215 insufficient remaining memory (or virtual memory) to satisfy the
4218 The request was judged to be small, so the possibility to trap it
4219 depends on the way perl was compiled. By default it is not trappable.
4220 However, if compiled for this, Perl may use the contents of C<$^M> as an
4221 emergency pool after die()ing with this message. In this case the error
4222 is trappable I<once>, and the error message will include the line and file
4223 where the failed request happened.
4225 =item Out of memory during ridiculously large request
4227 (F) You can't allocate more than 2^31+"small amount" bytes. This error
4228 is most likely to be caused by a typo in the Perl program. e.g.,
4229 C<$arr[time]> instead of C<$arr[$time]>.
4231 =item Out of memory for yacc stack
4233 (F) The yacc parser wanted to grow its stack so it could continue
4234 parsing, but realloc() wouldn't give it more memory, virtual or
4237 =item '.' outside of string in pack
4239 (F) The argument to a '.' in your template tried to move the working
4240 position to before the start of the packed string being built.
4242 =item '@' outside of string in unpack
4244 (F) You had a template that specified an absolute position outside
4245 the string being unpacked. See L<perlfunc/pack>.
4247 =item '@' outside of string with malformed UTF-8 in unpack
4249 (F) You had a template that specified an absolute position outside
4250 the string being unpacked. The string being unpacked was also invalid
4251 UTF-8. See L<perlfunc/pack>.
4253 =item overload arg '%s' is invalid
4255 (W overload) The L<overload> pragma was passed an argument it did not
4256 recognize. Did you mistype an operator?
4258 =item Overloaded dereference did not return a reference
4260 (F) An object with an overloaded dereference operator was dereferenced,
4261 but the overloaded operation did not return a reference. See
4264 =item Overloaded qr did not return a REGEXP
4266 (F) An object with a C<qr> overload was used as part of a match, but the
4267 overloaded operation didn't return a compiled regexp. See L<overload>.
4269 =item %s package attribute may clash with future reserved word: %s
4271 (W reserved) A lowercase attribute name was used that had a
4272 package-specific handler. That name might have a meaning to Perl itself
4273 some day, even though it doesn't yet. Perhaps you should use a
4274 mixed-case attribute name, instead. See L<attributes>.
4276 =item pack/unpack repeat count overflow
4278 (F) You can't specify a repeat count so large that it overflows your
4279 signed integers. See L<perlfunc/pack>.
4283 (W io) A single call to write() produced more lines than can fit on a
4284 page. See L<perlform>.
4288 (P) An internal error.
4290 =item panic: attempt to call %s in %s
4292 (P) One of the file test operators entered a code branch that calls
4293 an ACL related-function, but that function is not available on this
4294 platform. Earlier checks mean that it should not be possible to
4295 enter this branch on this platform.
4297 =item panic: child pseudo-process was never scheduled
4299 (P) A child pseudo-process in the ithreads implementation on Windows
4300 was not scheduled within the time period allowed and therefore was not
4301 able to initialize properly.
4303 =item panic: ck_grep, type=%u
4305 (P) Failed an internal consistency check trying to compile a grep.
4307 =item panic: ck_split, type=%u
4309 (P) Failed an internal consistency check trying to compile a split.
4311 =item panic: corrupt saved stack index %ld
4313 (P) The savestack was requested to restore more localized values than
4314 there are in the savestack.
4316 =item panic: del_backref
4318 (P) Failed an internal consistency check while trying to reset a weak
4323 (P) We popped the context stack to an eval context, and then discovered
4324 it wasn't an eval context.
4326 =item panic: do_subst
4328 (P) The internal pp_subst() routine was called with invalid operational
4331 =item panic: do_trans_%s
4333 (P) The internal do_trans routines were called with invalid operational
4336 =item panic: fold_constants JMPENV_PUSH returned %d
4338 (P) While attempting folding constants an exception other than an C<eval>
4341 =item panic: frexp: %f
4343 (P) The library function frexp() failed, making printf("%f") impossible.
4345 =item panic: goto, type=%u, ix=%ld
4347 (P) We popped the context stack to a context with the specified label,
4348 and then discovered it wasn't a context we know how to do a goto in.
4350 =item panic: gp_free failed to free glob pointer
4352 (P) The internal routine used to clear a typeglob's entries tried
4353 repeatedly, but each time something re-created entries in the glob.
4354 Most likely the glob contains an object with a reference back to
4355 the glob and a destructor that adds a new object to the glob.
4357 =item panic: INTERPCASEMOD, %s
4359 (P) The lexer got into a bad state at a case modifier.
4361 =item panic: INTERPCONCAT, %s
4363 (P) The lexer got into a bad state parsing a string with brackets.
4365 =item panic: kid popen errno read
4367 (F) A forked child returned an incomprehensible message about its errno.
4369 =item panic: last, type=%u
4371 (P) We popped the context stack to a block context, and then discovered
4372 it wasn't a block context.
4374 =item panic: leave_scope clearsv
4376 (P) A writable lexical variable became read-only somehow within the
4379 =item panic: leave_scope inconsistency %u
4381 (P) The savestack probably got out of sync. At least, there was an
4382 invalid enum on the top of it.
4384 =item panic: magic_killbackrefs
4386 (P) Failed an internal consistency check while trying to reset all weak
4387 references to an object.
4389 =item panic: malloc, %s
4391 (P) Something requested a negative number of bytes of malloc.
4393 =item panic: memory wrap
4395 (P) Something tried to allocate either more memory than possible or a
4398 =item panic: pad_alloc, %p!=%p
4400 (P) The compiler got confused about which scratch pad it was allocating
4401 and freeing temporaries and lexicals from.
4403 =item panic: pad_free curpad, %p!=%p
4405 (P) The compiler got confused about which scratch pad it was allocating
4406 and freeing temporaries and lexicals from.
4408 =item panic: pad_free po
4410 (P) A zero scratch pad offset was detected internally. An attempt was
4411 made to free a target that had not been allocated to begin with.
4413 =item panic: pad_reset curpad, %p!=%p
4415 (P) The compiler got confused about which scratch pad it was allocating
4416 and freeing temporaries and lexicals from.
4418 =item panic: pad_sv po
4420 (P) A zero scratch pad offset was detected internally. Most likely
4421 an operator needed a target but that target had not been allocated
4422 for whatever reason.
4424 =item panic: pad_swipe curpad, %p!=%p
4426 (P) The compiler got confused about which scratch pad it was allocating
4427 and freeing temporaries and lexicals from.
4429 =item panic: pad_swipe po
4431 (P) An invalid scratch pad offset was detected internally.
4433 =item panic: pp_iter, type=%u
4435 (P) The foreach iterator got called in a non-loop context frame.
4437 =item panic: pp_match%s
4439 (P) The internal pp_match() routine was called with invalid operational
4442 =item panic: pp_split, pm=%p, s=%p
4444 (P) Something terrible went wrong in setting up for the split.
4446 =item panic: realloc, %s
4448 (P) Something requested a negative number of bytes of realloc.
4450 =item panic: reference miscount on nsv in sv_replace() (%d != 1)
4452 (P) The internal sv_replace() function was handed a new SV with a
4453 reference count other than 1.
4455 =item panic: restartop in %s
4457 (P) Some internal routine requested a goto (or something like it), and
4458 didn't supply the destination.
4460 =item panic: return, type=%u
4462 (P) We popped the context stack to a subroutine or eval context, and
4463 then discovered it wasn't a subroutine or eval context.
4465 =item panic: scan_num, %s
4467 (P) scan_num() got called on something that wasn't a number.
4469 =item panic: Sequence (?{...}): no code block found in regex m/%s/
4471 (P) While compiling a pattern that has embedded (?{}) or (??{}) code
4472 blocks, perl couldn't locate the code block that should have already been
4473 seen and compiled by perl before control passed to the regex compiler.
4475 =item panic: strxfrm() gets absurd - a => %u, ab => %u
4477 (P) The interpreter's sanity check of the C function strxfrm() failed.
4478 In your current locale the returned transformation of the string "ab"
4479 is shorter than that of the string "a", which makes no sense.
4481 =item panic: sv_chop %s
4483 (P) The sv_chop() routine was passed a position that is not within the
4484 scalar's string buffer.
4486 =item panic: sv_insert, midend=%p, bigend=%p
4488 (P) The sv_insert() routine was told to remove more string than there
4491 =item panic: top_env
4493 (P) The compiler attempted to do a goto, or something weird like that.
4495 =item panic: unimplemented op %s (#%d) called
4497 (P) The compiler is screwed up and attempted to use an op that isn't
4498 permitted at run time.
4500 =item panic: utf16_to_utf8: odd bytelen
4502 (P) Something tried to call utf16_to_utf8 with an odd (as opposed
4503 to even) byte length.
4505 =item panic: utf16_to_utf8_reversed: odd bytelen
4507 (P) Something tried to call utf16_to_utf8_reversed with an odd (as opposed
4508 to even) byte length.
4510 =item panic: yylex, %s
4512 (P) The lexer got into a bad state while processing a case modifier.
4514 =item Parentheses missing around "%s" list
4516 (W parenthesis) You said something like
4522 my ($foo, $bar) = @_;
4524 Remember that "my", "our", "local" and "state" bind tighter than comma.
4526 =item Parsing code internal error (%s)
4528 (F) Parsing code supplied by an extension violated the parser's API in
4531 =item Passing malformed UTF-8 to "%s" is deprecated
4533 (D deprecated, utf8) This message indicates a bug either in the Perl
4534 core or in XS code. Such code was trying to find out if a character,
4535 allegedly stored internally encoded as UTF-8, was of a given type, such
4536 as being punctuation or a digit. But the character was not encoded in
4537 legal UTF-8. The C<%s> is replaced by a string that can be used by
4538 knowledgeable people to determine what the type being checked against
4539 was. If C<utf8> warnings are enabled, a further message is raised,
4540 giving details of the malformation.
4542 =item Pattern subroutine nesting without pos change exceeded limit in regex
4544 (F) You used a pattern that uses too many nested subpattern calls without
4545 consuming any text. Restructure the pattern so text is consumed before
4546 the nesting limit is exceeded.
4548 =item C<-p> destination: %s
4550 (F) An error occurred during the implicit output invoked by the C<-p>
4551 command-line switch. (This output goes to STDOUT unless you've
4552 redirected it with select().)
4554 =item Perl API version %s of %s does not match %s
4556 (F) The XS module in question was compiled against a different incompatible
4557 version of Perl than the one that has loaded the XS module.
4559 =item Perl folding rules are not up-to-date for 0x%X; please use the perlbug
4560 utility to report; in regex; marked by S<<-- HERE> in m/%s/
4562 (S regexp) You used a regular expression with case-insensitive matching,
4563 and there is a bug in Perl in which the built-in regular expression
4564 folding rules are not accurate. This may lead to incorrect results.
4565 Please report this as a bug using the L<perlbug> utility.
4567 =item PerlIO layer ':win32' is experimental
4569 (S experimental::win32_perlio) The C<:win32> PerlIO layer is
4570 experimental. If you want to take the risk of using this layer,
4571 simply disable this warning:
4573 no warnings "experimental::win32_perlio";
4575 =item Perl_my_%s() not available
4577 (F) Your platform has very uncommon byte-order and integer size,
4578 so it was not possible to set up some or all fixed-width byte-order
4579 conversion functions. This is only a problem when you're using the
4580 '<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
4582 =item Perl %s required (did you mean %s?)--this is only %s, stopped
4584 (F) The code you are trying to run has asked for a newer version of
4585 Perl than you are running. Perhaps C<use 5.10> was written instead
4586 of C<use 5.010> or C<use v5.10>. Without the leading C<v>, the number is
4587 interpreted as a decimal, with every three digits after the
4588 decimal point representing a part of the version number. So 5.10
4589 is equivalent to v5.100.
4591 =item Perl %s required--this is only %s, stopped
4593 (F) The module in question uses features of a version of Perl more
4594 recent than the currently running version. How long has it been since
4595 you upgraded, anyway? See L<perlfunc/require>.
4597 =item PERL_SH_DIR too long
4599 (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
4600 C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
4602 =item PERL_SIGNALS illegal: "%s"
4604 (X) See L<perlrun/PERL_SIGNALS> for legal values.
4606 =item Perls since %s too modern--this is %s, stopped
4608 (F) The code you are trying to run claims it will not run
4609 on the version of Perl you are using because it is too new.
4610 Maybe the code needs to be updated, or maybe it is simply
4611 wrong and the version check should just be removed.
4613 =item perl: warning: Non hex character in '$ENV{PERL_HASH_SEED}', seed only partially set
4615 (S) PERL_HASH_SEED should match /^\s*(?:0x)?[0-9a-fA-F]+\s*\z/ but it
4616 contained a non hex character. This could mean you are not using the
4617 hash seed you think you are.
4619 =item perl: warning: Setting locale failed.
4621 (S) The whole warning message will look something like:
4623 perl: warning: Setting locale failed.
4624 perl: warning: Please check that your locale settings:
4627 are supported and installed on your system.
4628 perl: warning: Falling back to the standard locale ("C").
4630 Exactly what were the failed locale settings varies. In the above the
4631 settings were that the LC_ALL was "En_US" and the LANG had no value.
4632 This error means that Perl detected that you and/or your operating
4633 system supplier and/or system administrator have set up the so-called
4634 locale system but Perl could not use those settings. This was not
4635 dead serious, fortunately: there is a "default locale" called "C" that
4636 Perl can and will use, and the script will be run. Before you really
4637 fix the problem, however, you will get the same error message each
4638 time you run Perl. How to really fix the problem can be found in
4639 L<perllocale> section B<LOCALE PROBLEMS>.
4641 =item perl: warning: strange setting in '$ENV{PERL_PERTURB_KEYS}': '%s'
4643 (S) Perl was run with the environment variable PERL_PERTURB_KEYS defined
4644 but containing an unexpected value. The legal values of this setting
4647 Numeric | String | Result
4648 --------+---------------+-----------------------------------------
4649 0 | NO | Disables key traversal randomization
4650 1 | RANDOM | Enables full key traversal randomization
4651 2 | DETERMINISTIC | Enables repeatable key traversal
4654 Both numeric and string values are accepted, but note that string values are
4655 case sensitive. The default for this setting is "RANDOM" or 1.
4657 =item pid %x not a child
4659 (W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
4660 process which isn't a subprocess of the current process. While this is
4661 fine from VMS' perspective, it's probably not what you intended.
4663 =item 'P' must have an explicit size in unpack
4665 (F) The unpack format P must have an explicit size, not "*".
4667 =item POSIX class [:%s:] unknown in regex; marked by S<<-- HERE> in m/%s/
4669 (F) The class in the character class [: :] syntax is unknown. The S<<-- HERE>
4670 shows whereabouts in the regular expression the problem was discovered.
4671 Note that the POSIX character classes do B<not> have the C<is> prefix
4672 the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
4673 not C<isprint>. See L<perlre>.
4675 =item POSIX getpgrp can't take an argument
4677 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
4678 the BSD version, which takes a pid.
4680 =item POSIX syntax [%c %c] belongs inside character classes in regex; marked by
4681 S<<-- HERE> in m/%s/
4683 (W regexp) The character class constructs [: :], [= =], and [. .] go
4684 I<inside> character classes, the [] are part of the construct, for example:
4685 /[012[:alpha:]345]/. Note that [= =] and [. .] are not currently
4686 implemented; they are simply placeholders for future extensions and
4687 will cause fatal errors. The S<<-- HERE> shows whereabouts in the regular
4688 expression the problem was discovered. See L<perlre>.
4690 =item POSIX syntax [. .] is reserved for future extensions in regex; marked by
4691 S<<-- HERE> in m/%s/
4693 (F) Within regular expression character classes ([]) the syntax beginning
4694 with "[." and ending with ".]" is reserved for future extensions. If you
4695 need to represent those character sequences inside a regular expression
4696 character class, just quote the square brackets with the backslash: "\[."
4697 and ".\]". The S<<-- HERE> shows whereabouts in the regular expression the
4698 problem was discovered. See L<perlre>.
4700 =item POSIX syntax [= =] is reserved for future extensions in regex; marked by
4701 S<<-- HERE> in m/%s/
4703 (F) Within regular expression character classes ([]) the syntax beginning
4704 with "[=" and ending with "=]" is reserved for future extensions. If you
4705 need to represent those character sequences inside a regular expression
4706 character class, just quote the square brackets with the backslash: "\[="
4707 and "=\]". The S<<-- HERE> shows whereabouts in the regular expression the
4708 problem was discovered. See L<perlre>.
4710 =item Possible attempt to put comments in qw() list
4712 (W qw) qw() lists contain items separated by whitespace; as with literal
4713 strings, comment characters are not ignored, but are instead treated as
4714 literal data. (You may have used different delimiters than the
4715 parentheses shown here; braces are also frequently used.)
4717 You probably wrote something like this:
4724 when you should have written this:
4731 If you really want comments, build your list the
4732 old-fashioned way, with quotes and commas:
4736 'b', # another comment
4739 =item Possible attempt to separate words with commas
4741 (W qw) qw() lists contain items separated by whitespace; therefore
4742 commas aren't needed to separate the items. (You may have used
4743 different delimiters than the parentheses shown here; braces are also
4746 You probably wrote something like this:
4750 which puts literal commas into some of the list items. Write it without
4751 commas if you don't want them to appear in your data:
4755 =item Possible memory corruption: %s overflowed 3rd argument
4757 (F) An ioctl() or fcntl() returned more than Perl was bargaining for.
4758 Perl guesses a reasonable buffer size, but puts a sentinel byte at the
4759 end of the buffer just in case. This sentinel byte got clobbered, and
4760 Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
4762 =item Possible precedence issue with control flow operator
4764 (W syntax) There is a possible problem with the mixing of a control
4765 flow operator (e.g. C<return>) and a low-precedence operator like
4768 sub { return $a or $b; }
4772 sub { (return $a) or $b; }
4774 Which is effectively just:
4778 Either use parentheses or the high-precedence variant of the operator.
4780 Note this may be also triggered for constructs like:
4784 =item Possible precedence problem on bitwise %s operator
4786 (W precedence) Your program uses a bitwise logical operator in conjunction
4787 with a numeric comparison operator, like this :
4789 if ($x & $y == 0) { ... }
4791 This expression is actually equivalent to C<$x & ($y == 0)>, due to the
4792 higher precedence of C<==>. This is probably not what you want. (If you
4793 really meant to write this, disable the warning, or, better, put the
4794 parentheses explicitly and write C<$x & ($y == 0)>).
4796 =item Possible unintended interpolation of $\ in regex
4798 (W ambiguous) You said something like C<m/$\/> in a regex.
4799 The regex C<m/foo$\s+bar/m> translates to: match the word 'foo', the output
4800 record separator (see L<perlvar/$\>) and the letter 's' (one time or more)
4801 followed by the word 'bar'.
4803 If this is what you intended then you can silence the warning by using
4804 C<m/${\}/> (for example: C<m/foo${\}s+bar/>).
4806 If instead you intended to match the word 'foo' at the end of the line
4807 followed by whitespace and the word 'bar' on the next line then you can use
4808 C<m/$(?)\/> (for example: C<m/foo$(?)\s+bar/>).
4810 =item Possible unintended interpolation of %s in string
4812 (W ambiguous) You said something like '@foo' in a double-quoted string
4813 but there was no array C<@foo> in scope at the time. If you wanted a
4814 literal @foo, then write it as \@foo; otherwise find out what happened
4815 to the array you apparently lost track of.
4817 =item Precedence problem: open %s should be open(%s)
4819 (S precedence) The old irregular construct
4823 is now misinterpreted as
4827 because of the strict regularization of Perl 5's grammar into unary and
4828 list operators. (The old open was a little of both.) You must put
4829 parentheses around the filehandle, or use the new "or" operator instead
4832 =item Premature end of script headers
4836 =item printf() on closed filehandle %s
4838 (W closed) The filehandle you're writing to got itself closed sometime
4839 before now. Check your control flow.
4841 =item print() on closed filehandle %s
4843 (W closed) The filehandle you're printing on got itself closed sometime
4844 before now. Check your control flow.
4846 =item Process terminated by SIG%s
4848 (W) This is a standard message issued by OS/2 applications, while *nix
4849 applications die in silence. It is considered a feature of the OS/2
4850 port. One can easily disable this by appropriate sighandlers, see
4851 L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
4854 =item Prototype after '%c' for %s : %s
4856 (W illegalproto) A character follows % or @ in a prototype. This is
4857 useless, since % and @ gobble the rest of the subroutine arguments.
4859 =item Prototype mismatch: %s vs %s
4861 (S prototype) The subroutine being declared or defined had previously been
4862 declared or defined with a different function prototype.
4864 =item Prototype not terminated
4866 (F) You've omitted the closing parenthesis in a function prototype
4869 =item Prototype '%s' overridden by attribute 'prototype(%s)' in %s
4871 (W prototype) A prototype was declared in both the parentheses after
4872 the sub name and via the prototype attribute. The prototype in
4873 parentheses is useless, since it will be replaced by the prototype
4874 from the attribute before it's ever used.
4876 =item Quantifier follows nothing in regex; marked by S<<-- HERE> in m/%s/
4878 (F) You started a regular expression with a quantifier. Backslash it if
4879 you meant it literally. The S<<-- HERE> shows whereabouts in the regular
4880 expression the problem was discovered. See L<perlre>.
4882 =item Quantifier in {,} bigger than %d in regex; marked by S<<-- HERE> in m/%s/
4884 (F) There is currently a limit to the size of the min and max values of
4885 the {min,max} construct. The S<<-- HERE> shows whereabouts in the regular
4886 expression the problem was discovered. See L<perlre>.
4888 =item Quantifier {n,m} with n > m can't match in regex
4890 =item Quantifier {n,m} with n > m can't match in regex; marked by
4891 S<<-- HERE> in m/%s/
4893 (W regexp) Minima should be less than or equal to maxima. If you really
4894 want your regexp to match something 0 times, just put {0}.
4896 =item Quantifier unexpected on zero-length expression in regex m/%s/
4898 (W regexp) You applied a regular expression quantifier in a place where
4899 it makes no sense, such as on a zero-width assertion. Try putting the
4900 quantifier inside the assertion instead. For example, the way to match
4901 "abc" provided that it is followed by three repetitions of "xyz" is
4902 C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
4904 =item Range iterator outside integer range
4906 (F) One (or both) of the numeric arguments to the range operator ".."
4907 are outside the range which can be represented by integers internally.
4908 One possible workaround is to force Perl to use magical string increment
4909 by prepending "0" to your numbers.
4911 =item Ranges of ASCII printables should be some subset of "0-9", "A-Z", or
4912 "a-z" in regex; marked by S<<-- HERE> in m/%s/
4914 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
4916 Stricter rules help to find typos and other errors. Perhaps you didn't
4917 even intend a range here, if the C<"-"> was meant to be some other
4918 character, or should have been escaped (like C<"\-">). If you did
4919 intend a range, the one that was used is not portable between ASCII and
4920 EBCDIC platforms, and doesn't have an obvious meaning to a casual
4923 [3-7] # OK; Obvious and portable
4924 [d-g] # OK; Obvious and portable
4925 [A-Y] # OK; Obvious and portable
4926 [A-z] # WRONG; Not portable; not clear what is meant
4927 [a-Z] # WRONG; Not portable; not clear what is meant
4928 [%-.] # WRONG; Not portable; not clear what is meant
4929 [\x41-Z] # WRONG; Not portable; not obvious to non-geek
4931 (You can force portability by specifying a Unicode range, which means that
4932 the endpoints are specified by
4933 L<C<\N{...}>|perlrecharclass/Character Ranges>, but the meaning may
4934 still not be obvious.)
4935 The stricter rules require that ranges that start or stop with an ASCII
4936 character that is not a control have all their endpoints be the literal
4937 character, and not some escape sequence (like C<"\x41">), and the ranges
4938 must be all digits, or all uppercase letters, or all lowercase letters.
4940 =item Ranges of digits should be from the same group in regex; marked by
4941 S<<-- HERE> in m/%s/
4943 (W regexp) (only under C<S<use re 'strict'>> or within C<(?[...])>)
4945 Stricter rules help to find typos and other errors. You included a
4946 range, and at least one of the end points is a decimal digit. Under the
4947 stricter rules, when this happens, both end points should be digits in
4948 the same group of 10 consecutive digits.
4950 =item readdir() attempted on invalid dirhandle %s
4952 (W io) The dirhandle you're reading from is either closed or not really
4953 a dirhandle. Check your control flow.
4955 =item readline() on closed filehandle %s
4957 (W closed) The filehandle you're reading from got itself closed sometime
4958 before now. Check your control flow.
4960 =item read() on closed filehandle %s
4962 (W closed) You tried to read from a closed filehandle.
4964 =item read() on unopened filehandle %s
4966 (W unopened) You tried to read from a filehandle that was never opened.
4968 =item Reallocation too large: %x
4970 (F) You can't allocate more than 64K on an MS-DOS machine.
4972 =item realloc() of freed memory ignored
4974 (S malloc) An internal routine called realloc() on something that had
4977 =item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
4979 (S debugging) You can't use the B<-D> option unless the code to produce
4980 the desired output is compiled into Perl, which entails some overhead,
4981 which is why it's currently left out of your copy.
4983 =item Recursive call to Perl_load_module in PerlIO_find_layer
4985 (P) It is currently not permitted to load modules when creating
4986 a filehandle inside an %INC hook. This can happen with C<open my
4987 $fh, '<', \$scalar>, which implicitly loads PerlIO::scalar. Try
4988 loading PerlIO::scalar explicitly first.
4990 =item Recursive inheritance detected in package '%s'
4992 (F) While calculating the method resolution order (MRO) of a package, Perl
4993 believes it found an infinite loop in the C<@ISA> hierarchy. This is a
4994 crude check that bails out after 100 levels of C<@ISA> depth.
4996 =item Redundant argument in %s
4998 (W redundant) You called a function with more arguments than other
4999 arguments you supplied indicated would be needed. Currently only
5000 emitted when a printf-type format required fewer arguments than were
5001 supplied, but might be used in the future for e.g. L<perlfunc/pack>.
5003 =item refcnt_dec: fd %d%s
5005 =item refcnt: fd %d%s
5007 =item refcnt_inc: fd %d%s
5009 (P) Perl's I/O implementation failed an internal consistency check. If
5010 you see this message, something is very wrong.
5012 =item Reference found where even-sized list expected
5014 (W misc) You gave a single reference where Perl was expecting a list
5015 with an even number of elements (for assignment to a hash). This
5016 usually means that you used the anon hash constructor when you meant
5017 to use parens. In any case, a hash requires key/value B<pairs>.
5019 %hash = { one => 1, two => 2, }; # WRONG
5020 %hash = [ qw/ an anon array / ]; # WRONG
5021 %hash = ( one => 1, two => 2, ); # right
5022 %hash = qw( one 1 two 2 ); # also fine
5024 =item Reference is already weak
5026 (W misc) You have attempted to weaken a reference that is already weak.
5027 Doing so has no effect.
5029 =item Reference to invalid group 0 in regex; marked by S<<-- HERE> in m/%s/
5031 (F) You used C<\g0> or similar in a regular expression. You may refer
5032 to capturing parentheses only with strictly positive integers
5033 (normal backreferences) or with strictly negative integers (relative
5034 backreferences). Using 0 does not make sense.
5036 =item Reference to nonexistent group in regex; marked by S<<-- HERE> in
5039 (F) You used something like C<\7> in your regular expression, but there are
5040 not at least seven sets of capturing parentheses in the expression. If
5041 you wanted to have the character with ordinal 7 inserted into the regular
5042 expression, prepend zeroes to make it three digits long: C<\007>
5044 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5047 =item Reference to nonexistent named group in regex; marked by S<<-- HERE>
5050 (F) You used something like C<\k'NAME'> or C<< \k<NAME> >> in your regular
5051 expression, but there is no corresponding named capturing parentheses
5052 such as C<(?'NAME'...)> or C<< (?<NAME>...) >>. Check if the name has been
5053 spelled correctly both in the backreference and the declaration.
5055 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5058 =item Reference to nonexistent or unclosed group in regex; marked by
5059 S<<-- HERE> in m/%s/
5061 (F) You used something like C<\g{-7}> in your regular expression, but there
5062 are not at least seven sets of closed capturing parentheses in the
5063 expression before where the C<\g{-7}> was located.
5065 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5068 =item regexp memory corruption
5070 (P) The regular expression engine got confused by what the regular
5071 expression compiler gave it.
5073 =item Regexp modifier "/%c" may appear a maximum of twice
5075 =item Regexp modifier "%c" may appear a maximum of twice in regex; marked
5076 by S<<-- HERE> in m/%s/
5078 (F) The regular expression pattern had too many occurrences
5079 of the specified modifier. Remove the extraneous ones.
5081 =item Regexp modifier "%c" may not appear after the "-" in regex; marked by <--
5084 (F) Turning off the given modifier has the side effect of turning on
5085 another one. Perl currently doesn't allow this. Reword the regular
5086 expression to use the modifier you want to turn on (and place it before
5087 the minus), instead of the one you want to turn off.
5089 =item Regexp modifier "/%c" may not appear twice
5091 =item Regexp modifier "%c" may not appear twice in regex; marked by <--
5094 (F) The regular expression pattern had too many occurrences
5095 of the specified modifier. Remove the extraneous ones.
5097 =item Regexp modifiers "/%c" and "/%c" are mutually exclusive
5099 =item Regexp modifiers "%c" and "%c" are mutually exclusive in regex;
5100 marked by S<<-- HERE> in m/%s/
5102 (F) The regular expression pattern had more than one of these
5103 mutually exclusive modifiers. Retain only the modifier that is
5104 supposed to be there.
5106 =item Regexp out of space in regex m/%s/
5108 (P) A "can't happen" error, because safemalloc() should have caught it
5111 =item Repeated format line will never terminate (~~ and @#)
5113 (F) Your format contains the ~~ repeat-until-blank sequence and a
5114 numeric field that will never go blank so that the repetition never
5115 terminates. You might use ^# instead. See L<perlform>.
5117 =item Replacement list is longer than search list
5119 (W misc) You have used a replacement list that is longer than the
5120 search list. So the additional elements in the replacement list
5123 =item '%s' resolved to '\o{%s}%d'
5125 (W misc, regexp) You wrote something like C<\08>, or C<\179> in a
5126 double-quotish string. All but the last digit is treated as a single
5127 character, specified in octal. The last digit is the next character in
5128 the string. To tell Perl that this is indeed what you want, you can use
5129 the C<\o{ }> syntax, or use exactly three digits to specify the octal
5132 =item Reversed %s= operator
5134 (W syntax) You wrote your assignment operator backwards. The = must
5135 always come last, to avoid ambiguity with subsequent unary operators.
5137 =item rewinddir() attempted on invalid dirhandle %s
5139 (W io) The dirhandle you tried to do a rewinddir() on is either closed
5140 or not really a dirhandle. Check your control flow.
5142 =item Scalars leaked: %d
5144 (S internal) Something went wrong in Perl's internal bookkeeping
5145 of scalars: not all scalar variables were deallocated by the time
5146 Perl exited. What this usually indicates is a memory leak, which
5147 is of course bad, especially if the Perl program is intended to be
5150 =item Scalar value @%s[%s] better written as $%s[%s]
5152 (W syntax) You've used an array slice (indicated by @) to select a
5153 single element of an array. Generally it's better to ask for a scalar
5154 value (indicated by $). The difference is that C<$foo[&bar]> always
5155 behaves like a scalar, both when assigning to it and when evaluating its
5156 argument, while C<@foo[&bar]> behaves like a list when you assign to it,
5157 and provides a list context to its subscript, which can do weird things
5158 if you're expecting only one subscript.
5160 On the other hand, if you were actually hoping to treat the array
5161 element as a list, you need to look into how references work, because
5162 Perl will not magically convert between scalars and lists for you. See
5165 =item Scalar value @%s{%s} better written as $%s{%s}
5167 (W syntax) You've used a hash slice (indicated by @) to select a single
5168 element of a hash. Generally it's better to ask for a scalar value
5169 (indicated by $). The difference is that C<$foo{&bar}> always behaves
5170 like a scalar, both when assigning to it and when evaluating its
5171 argument, while C<@foo{&bar}> behaves like a list when you assign to it,
5172 and provides a list context to its subscript, which can do weird things
5173 if you're expecting only one subscript.
5175 On the other hand, if you were actually hoping to treat the hash element
5176 as a list, you need to look into how references work, because Perl will
5177 not magically convert between scalars and lists for you. See
5180 =item Search pattern not terminated
5182 (F) The lexer couldn't find the final delimiter of a // or m{}
5183 construct. Remember that bracketing delimiters count nesting level.
5184 Missing the leading C<$> from a variable C<$m> may cause this error.
5186 Note that since Perl 5.10.0 a // can also be the I<defined-or>
5187 construct, not just the empty search pattern. Therefore code written
5188 in Perl 5.10.0 or later that uses the // as the I<defined-or> can be
5189 misparsed by pre-5.10.0 Perls as a non-terminated search pattern.
5191 =item seekdir() attempted on invalid dirhandle %s
5193 (W io) The dirhandle you are doing a seekdir() on is either closed or not
5194 really a dirhandle. Check your control flow.
5196 =item %sseek() on unopened filehandle
5198 (W unopened) You tried to use the seek() or sysseek() function on a
5199 filehandle that was either never opened or has since been closed.
5201 =item select not implemented
5203 (F) This machine doesn't implement the select() system call.
5205 =item Self-ties of arrays and hashes are not supported
5207 (F) Self-ties are of arrays and hashes are not supported in
5208 the current implementation.
5210 =item Semicolon seems to be missing
5212 (W semicolon) A nearby syntax error was probably caused by a missing
5213 semicolon, or possibly some other missing operator, such as a comma.
5215 =item semi-panic: attempt to dup freed string
5217 (S internal) The internal newSVsv() routine was called to duplicate a
5218 scalar that had previously been marked as free.
5220 =item sem%s not implemented
5222 (F) You don't have System V semaphore IPC on your system.
5224 =item send() on closed socket %s
5226 (W closed) The socket you're sending to got itself closed sometime
5227 before now. Check your control flow.
5229 =item Sequence "\c{" invalid
5231 (F) These three characters may not appear in sequence in a
5232 double-quotish context. This message is raised only on non-ASCII
5233 platforms (a different error message is output on ASCII ones). If you
5234 were intending to specify a control character with this sequence, you'll
5235 have to use a different way to specify it.
5237 =item Sequence (? incomplete in regex; marked by S<<-- HERE> in m/%s/
5239 (F) A regular expression ended with an incomplete extension (?. The
5240 S<<-- HERE> shows whereabouts in the regular expression the problem was
5241 discovered. See L<perlre>.
5243 =item Sequence (?%c...) not implemented in regex; marked by S<<-- HERE> in
5246 (F) A proposed regular expression extension has the character reserved
5247 but has not yet been written. The S<<-- HERE> shows whereabouts in the
5248 regular expression the problem was discovered. See L<perlre>.
5250 =item Sequence (?%s...) not recognized in regex; marked by S<<-- HERE> in
5253 (F) You used a regular expression extension that doesn't make sense.
5254 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5255 discovered. This may happen when using the C<(?^...)> construct to tell
5256 Perl to use the default regular expression modifiers, and you
5257 redundantly specify a default modifier. For other
5258 causes, see L<perlre>.
5260 =item Sequence (?#... not terminated in regex m/%s/
5262 (F) A regular expression comment must be terminated by a closing
5263 parenthesis. Embedded parentheses aren't allowed. See
5266 =item Sequence (?&... not terminated in regex; marked by S<<-- HERE> in
5269 (F) A named reference of the form C<(?&...)> was missing the final
5270 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5271 in the regular expression the problem was discovered.
5273 =item Sequence (?%c... not terminated in regex; marked by S<<-- HERE>
5276 (F) A named group of the form C<(?'...')> or C<< (?<...>) >> was missing the final
5277 closing quote or angle bracket. The S<<-- HERE> shows whereabouts in the
5278 regular expression the problem was discovered.
5280 =item Sequence (?(%c... not terminated in regex; marked by S<<-- HERE>
5283 (F) A named reference of the form C<(?('...')...)> or C<< (?(<...>)...) >> was
5284 missing the final closing quote or angle bracket after the name. The
5285 S<<-- HERE> shows whereabouts in the regular expression the problem was
5288 =item Sequence (?... not terminated in regex; marked by S<<-- HERE> in
5291 (F) There was no matching closing parenthesis for the '('. The
5292 S<<-- HERE> shows whereabouts in the regular expression the problem was
5295 =item Sequence \%s... not terminated in regex; marked by S<<-- HERE> in
5298 (F) The regular expression expects a mandatory argument following the escape
5299 sequence and this has been omitted or incorrectly written.
5301 =item Sequence (?{...}) not terminated with ')'
5303 (F) The end of the perl code contained within the {...} must be
5304 followed immediately by a ')'.
5306 =item Sequence ?P=... not terminated in regex; marked by S<<-- HERE> in
5309 (F) A named reference of the form C<(?P=...)> was missing the final
5310 closing parenthesis after the name. The S<<-- HERE> shows whereabouts
5311 in the regular expression the problem was discovered.
5313 =item Sequence (?R) not terminated in regex m/%s/
5315 (F) An C<(?R)> or C<(?0)> sequence in a regular expression was missing the
5318 =item Server error (a.k.a. "500 Server error")
5320 (A) This is the error message generally seen in a browser window
5321 when trying to run a CGI program (including SSI) over the web. The
5322 actual error text varies widely from server to server. The most
5323 frequently-seen variants are "500 Server error", "Method (something)
5324 not permitted", "Document contains no data", "Premature end of script
5325 headers", and "Did not produce a valid header".
5327 B<This is a CGI error, not a Perl error>.
5329 You need to make sure your script is executable, is accessible by
5330 the user CGI is running the script under (which is probably not the
5331 user account you tested it under), does not rely on any environment
5332 variables (like PATH) from the user it isn't running under, and isn't
5333 in a location where the CGI server can't find it, basically, more or
5334 less. Please see the following for more information:
5336 http://www.perl.org/CGI_MetaFAQ.html
5337 http://www.htmlhelp.org/faq/cgifaq.html
5338 http://www.w3.org/Security/Faq/
5340 You should also look at L<perlfaq9>.
5342 =item setegid() not implemented
5344 (F) You tried to assign to C<$)>, and your operating system doesn't
5345 support the setegid() system call (or equivalent), or at least Configure
5348 =item seteuid() not implemented
5350 (F) You tried to assign to C<< $> >>, and your operating system doesn't
5351 support the seteuid() system call (or equivalent), or at least Configure
5354 =item setpgrp can't take arguments
5356 (F) Your system has the setpgrp() from BSD 4.2, which takes no
5357 arguments, unlike POSIX setpgid(), which takes a process ID and process
5360 =item setrgid() not implemented
5362 (F) You tried to assign to C<$(>, and your operating system doesn't
5363 support the setrgid() system call (or equivalent), or at least Configure
5366 =item setruid() not implemented
5368 (F) You tried to assign to C<$<>, and your operating system doesn't
5369 support the setruid() system call (or equivalent), or at least Configure
5372 =item setsockopt() on closed socket %s
5374 (W closed) You tried to set a socket option on a closed socket. Did you
5375 forget to check the return value of your socket() call? See
5376 L<perlfunc/setsockopt>.
5378 =item Setting ${^ENCODING} is deprecated
5380 (D deprecated) You assigned a non-C<undef> value to C<${^ENCODING}>.
5381 This is deprecated; see C<L<perlvar/${^ENCODING}>> for details.
5383 =item Setting $/ to a reference to %s as a form of slurp is deprecated, treating as undef
5385 (D deprecated) You assigned a reference to a scalar to C<$/> where the
5386 referenced item is not a positive integer. In older perls this B<appeared>
5387 to work the same as setting it to C<undef> but was in fact internally
5388 different, less efficient and with very bad luck could have resulted in
5389 your file being split by a stringified form of the reference.
5391 In Perl 5.20.0 this was changed so that it would be B<exactly> the same as
5392 setting C<$/> to undef, with the exception that this warning would be
5395 You are recommended to change your code to set C<$/> to C<undef> explicitly
5396 if you wish to slurp the file. In future versions of Perl assigning
5397 a reference to will throw a fatal error.
5399 =item Setting $/ to %s reference is forbidden
5401 (F) You tried to assign a reference to a non integer to C<$/>. In older
5402 Perls this would have behaved similarly to setting it to a reference to
5403 a positive integer, where the integer was the address of the reference.
5404 As of Perl 5.20.0 this is a fatal error, to allow future versions of Perl
5405 to use non-integer refs for more interesting purposes.
5407 =item shm%s not implemented
5409 (F) You don't have System V shared memory IPC on your system.
5411 =item !=~ should be !~
5413 (W syntax) The non-matching operator is !~, not !=~. !=~ will be
5414 interpreted as the != (numeric not equal) and ~ (1's complement)
5415 operators: probably not what you intended.
5417 =item /%s/ should probably be written as "%s"
5419 (W syntax) You have used a pattern where Perl expected to find a string,
5420 as in the first argument to C<join>. Perl will treat the true or false
5421 result of matching the pattern against $_ as the string, which is
5422 probably not what you had in mind.
5424 =item shutdown() on closed socket %s
5426 (W closed) You tried to do a shutdown on a closed socket. Seems a bit
5429 =item SIG%s handler "%s" not defined
5431 (W signal) The signal handler named in %SIG doesn't, in fact, exist.
5432 Perhaps you put it into the wrong package?
5434 =item Slab leaked from cv %p
5436 (S) If you see this message, then something is seriously wrong with the
5437 internal bookkeeping of op trees. An op tree needed to be freed after
5438 a compilation error, but could not be found, so it was leaked instead.
5440 =item sleep(%u) too large
5442 (W overflow) You called C<sleep> with a number that was larger than
5443 it can reliably handle and C<sleep> probably slept for less time than
5446 =item Slurpy parameter not last
5448 (F) In a subroutine signature, you put something after a slurpy (array or
5449 hash) parameter. The slurpy parameter takes all the available arguments,
5450 so there can't be any left to fill later parameters.
5452 =item Smart matching a non-overloaded object breaks encapsulation
5454 (F) You should not use the C<~~> operator on an object that does not
5455 overload it: Perl refuses to use the object's underlying structure
5456 for the smart match.
5458 =item Smartmatch is experimental
5460 (S experimental::smartmatch) This warning is emitted if you
5461 use the smartmatch (C<~~>) operator. This is currently an experimental
5462 feature, and its details are subject to change in future releases of
5463 Perl. Particularly, its current behavior is noticed for being
5464 unnecessarily complex and unintuitive, and is very likely to be
5467 =item sort is now a reserved word
5469 (F) An ancient error message that almost nobody ever runs into anymore.
5470 But before sort was a keyword, people sometimes used it as a filehandle.
5472 =item Source filters apply only to byte streams
5474 (F) You tried to activate a source filter (usually by loading a
5475 source filter module) within a string passed to C<eval>. This is
5476 not permitted under the C<unicode_eval> feature. Consider using
5477 C<evalbytes> instead. See L<feature>.
5479 =item splice() offset past end of array
5481 (W misc) You attempted to specify an offset that was past the end of
5482 the array passed to splice(). Splicing will instead commence at the
5483 end of the array, rather than past it. If this isn't what you want,
5484 try explicitly pre-extending the array by assigning $#array = $offset.
5485 See L<perlfunc/splice>.
5489 (P) The split was looping infinitely. (Obviously, a split shouldn't
5490 iterate more times than there are characters of input, which is what
5491 happened.) See L<perlfunc/split>.
5493 =item Statement unlikely to be reached
5495 (W exec) You did an exec() with some statement after it other than a
5496 die(). This is almost always an error, because exec() never returns
5497 unless there was a failure. You probably wanted to use system()
5498 instead, which does return. To suppress this warning, put the exec() in
5501 =item "state" subroutine %s can't be in a package
5503 (F) Lexically scoped subroutines aren't in a package, so it doesn't make
5504 sense to try to declare one with a package qualifier on the front.
5506 =item "state %s" used in sort comparison
5508 (W syntax) The package variables $a and $b are used for sort comparisons.
5509 You used $a or $b in as an operand to the C<< <=> >> or C<cmp> operator inside a
5510 sort comparison block, and the variable had earlier been declared as a
5511 lexical variable. Either qualify the sort variable with the package
5512 name, or rename the lexical variable.
5514 =item "state" variable %s can't be in a package
5516 (F) Lexically scoped variables aren't in a package, so it doesn't make
5517 sense to try to declare one with a package qualifier on the front. Use
5518 local() if you want to localize a package variable.
5520 =item stat() on unopened filehandle %s
5522 (W unopened) You tried to use the stat() function on a filehandle that
5523 was either never opened or has since been closed.
5525 =item Strings with code points over 0xFF may not be mapped into in-memory file handles
5527 (W utf8) You tried to open a reference to a scalar for read or append
5528 where the scalar contained code points over 0xFF. In-memory files
5529 model on-disk files and can only contain bytes.
5531 =item Stub found while resolving method "%s" overloading "%s" in package "%s"
5533 (P) Overloading resolution over @ISA tree may be broken by importation
5534 stubs. Stubs should never be implicitly created, but explicit calls to
5535 C<can> may break this.
5537 =item Subroutine "&%s" is not available
5539 (W closure) During compilation, an inner named subroutine or eval is
5540 attempting to capture an outer lexical subroutine that is not currently
5541 available. This can happen for one of two reasons. First, the lexical
5542 subroutine may be declared in an outer anonymous subroutine that has
5543 not yet been created. (Remember that named subs are created at compile
5544 time, while anonymous subs are created at run-time.) For example,
5546 sub { my sub a {...} sub f { \&a } }
5548 At the time that f is created, it can't capture the current "a" sub,
5549 since the anonymous subroutine hasn't been created yet. Conversely, the
5550 following won't give a warning since the anonymous subroutine has by now
5551 been created and is live:
5553 sub { my sub a {...} eval 'sub f { \&a }' }->();
5555 The second situation is caused by an eval accessing a lexical subroutine
5556 that has gone out of scope, for example,
5564 Here, when the '\&a' in the eval is being compiled, f() is not currently
5565 being executed, so its &a is not available for capture.
5567 =item "%s" subroutine &%s masks earlier declaration in same %s
5569 (W misc) A "my" or "state" subroutine has been redeclared in the
5570 current scope or statement, effectively eliminating all access to
5571 the previous instance. This is almost always a typographical error.
5572 Note that the earlier subroutine will still exist until the end of
5573 the scope or until all closure references to it are destroyed.
5575 =item Subroutine %s redefined
5577 (W redefine) You redefined a subroutine. To suppress this warning, say
5580 no warnings 'redefine';
5581 eval "sub name { ... }";
5584 =item Subroutine "%s" will not stay shared
5586 (W closure) An inner (nested) I<named> subroutine is referencing a "my"
5587 subroutine defined in an outer named subroutine.
5589 When the inner subroutine is called, it will see the value of the outer
5590 subroutine's lexical subroutine as it was before and during the *first*
5591 call to the outer subroutine; in this case, after the first call to the
5592 outer subroutine is complete, the inner and outer subroutines will no
5593 longer share a common value for the lexical subroutine. In other words,
5594 it will no longer be shared. This will especially make a difference
5595 if the lexical subroutines accesses lexical variables declared in its
5598 This problem can usually be solved by making the inner subroutine
5599 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
5600 reference lexical subroutines in outer subroutines are created, they
5601 are automatically rebound to the current values of such lexical subs.
5603 =item Substitution loop
5605 (P) The substitution was looping infinitely. (Obviously, a substitution
5606 shouldn't iterate more times than there are characters of input, which
5607 is what happened.) See the discussion of substitution in
5608 L<perlop/"Regexp Quote-Like Operators">.
5610 =item Substitution pattern not terminated
5612 (F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
5613 construct. Remember that bracketing delimiters count nesting level.
5614 Missing the leading C<$> from variable C<$s> may cause this error.
5616 =item Substitution replacement not terminated
5618 (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
5619 construct. Remember that bracketing delimiters count nesting level.
5620 Missing the leading C<$> from variable C<$s> may cause this error.
5622 =item substr outside of string
5624 (W substr)(F) You tried to reference a substr() that pointed outside of
5625 a string. That is, the absolute value of the offset was larger than the
5626 length of the string. See L<perlfunc/substr>. This warning is fatal if
5627 substr is used in an lvalue context (as the left hand side of an
5628 assignment or as a subroutine argument for example).
5630 =item sv_upgrade from type %d down to type %d
5632 (P) Perl tried to force the upgrade of an SV to a type which was actually
5633 inferior to its current type.
5635 =item SWASHNEW didn't return an HV ref
5637 (P) Something went wrong internally when Perl was trying to look up
5640 =item Switch (?(condition)... contains too many branches in regex; marked by
5641 S<<-- HERE> in m/%s/
5643 (F) A (?(condition)if-clause|else-clause) construct can have at most
5644 two branches (the if-clause and the else-clause). If you want one or
5645 both to contain alternation, such as using C<this|that|other>, enclose
5646 it in clustering parentheses:
5648 (?(condition)(?:this|that|other)|else-clause)
5650 The S<<-- HERE> shows whereabouts in the regular expression the problem
5651 was discovered. See L<perlre>.
5653 =item Switch condition not recognized in regex; marked by S<<-- HERE> in
5656 (F) The condition part of a (?(condition)if-clause|else-clause) construct
5657 is not known. The condition must be one of the following:
5659 (1) (2) ... true if 1st, 2nd, etc., capture matched
5660 (<NAME>) ('NAME') true if named capture matched
5661 (?=...) (?<=...) true if subpattern matches
5662 (?!...) (?<!...) true if subpattern fails to match
5663 (?{ CODE }) true if code returns a true value
5664 (R) true if evaluating inside recursion
5665 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
5666 (R&NAME) true if directly inside named capture
5667 (DEFINE) always false; for defining named subpatterns
5669 The S<<-- HERE> shows whereabouts in the regular expression the problem was
5670 discovered. See L<perlre>.
5672 =item Switch (?(condition)... not terminated in regex; marked by
5673 S<<-- HERE> in m/%s/
5675 (F) You omitted to close a (?(condition)...) block somewhere
5676 in the pattern. Add a closing parenthesis in the appropriate
5677 position. See L<perlre>.
5679 =item switching effective %s is not implemented
5681 (F) While under the C<use filetest> pragma, we cannot switch the real
5682 and effective uids or gids.
5686 (F) Probably means you had a syntax error. Common reasons include:
5688 A keyword is misspelled.
5689 A semicolon is missing.
5691 An opening or closing parenthesis is missing.
5692 An opening or closing brace is missing.
5693 A closing quote is missing.
5695 Often there will be another error message associated with the syntax
5696 error giving more information. (Sometimes it helps to turn on B<-w>.)
5697 The error message itself often tells you where it was in the line when
5698 it decided to give up. Sometimes the actual error is several tokens
5699 before this, because Perl is good at understanding random input.
5700 Occasionally the line number may be misleading, and once in a blue moon
5701 the only way to figure out what's triggering the error is to call
5702 C<perl -c> repeatedly, chopping away half the program each time to see
5703 if the error went away. Sort of the cybernetic version of S<20 questions>.
5705 =item syntax error at line %d: '%s' unexpected
5707 (A) You've accidentally run your script through the Bourne shell instead
5708 of Perl. Check the #! line, or manually feed your script into Perl
5711 =item syntax error in file %s at line %d, next 2 tokens "%s"
5713 (F) This error is likely to occur if you run a perl5 script through
5714 a perl4 interpreter, especially if the next 2 tokens are "use strict"
5715 or "my $var" or "our $var".
5717 =item Syntax error in (?[...]) in regex m/%s/
5719 (F) Perl could not figure out what you meant inside this construct; this
5720 notifies you that it is giving up trying.
5724 (F) The final summary message when a C<perl -c> succeeds.
5726 =item sysread() on closed filehandle %s
5728 (W closed) You tried to read from a closed filehandle.
5730 =item sysread() on unopened filehandle %s
5732 (W unopened) You tried to read from a filehandle that was never opened.
5734 =item System V %s is not implemented on this machine
5736 (F) You tried to do something with a function beginning with "sem",
5737 "shm", or "msg" but that System V IPC is not implemented in your
5738 machine. In some machines the functionality can exist but be
5739 unconfigured. Consult your system support.
5741 =item syswrite() on closed filehandle %s
5743 (W closed) The filehandle you're writing to got itself closed sometime
5744 before now. Check your control flow.
5746 =item C<-T> and C<-B> not implemented on filehandles
5748 (F) Perl can't peek at the stdio buffer of filehandles when it doesn't
5749 know about your kind of stdio. You'll have to use a filename instead.
5751 =item Target of goto is too deeply nested
5753 (F) You tried to use C<goto> to reach a label that was too deeply nested
5754 for Perl to reach. Perl is doing you a favor by refusing.
5756 =item telldir() attempted on invalid dirhandle %s
5758 (W io) The dirhandle you tried to telldir() is either closed or not really
5759 a dirhandle. Check your control flow.
5761 =item tell() on unopened filehandle
5763 (W unopened) You tried to use the tell() function on a filehandle that
5764 was either never opened or has since been closed.
5766 =item That use of $[ is unsupported
5768 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
5769 as a compiler directive. You may say only one of
5778 This is to prevent the problem of one module changing the array base out
5779 from under another module inadvertently. See L<perlvar/$[> and L<arybase>.
5781 =item The bitwise feature is experimental
5783 (S experimental::bitwise) This warning is emitted if you use bitwise
5784 operators (C<& | ^ ~ &. |. ^. ~.>) with the "bitwise" feature enabled.
5785 Simply suppress the warning if you want to use the feature, but know
5786 that in doing so you are taking the risk of using an experimental
5787 feature which may change or be removed in a future Perl version:
5789 no warnings "experimental::bitwise";
5790 use feature "bitwise";
5793 =item The crypt() function is unimplemented due to excessive paranoia.
5795 (F) Configure couldn't find the crypt() function on your machine,
5796 probably because your vendor didn't supply it, probably because they
5797 think the U.S. Government thinks it's a secret, or at least that they
5798 will continue to pretend that it is. And if you quote me on that, I
5801 =item The %s function is unimplemented
5803 (F) The function indicated isn't implemented on this architecture,
5804 according to the probings of Configure.
5806 =item The lexical_subs feature is experimental
5808 (S experimental::lexical_subs) This warning is emitted if you
5809 declare a sub with C<my> or C<state>. Simply suppress the warning
5810 if you want to use the feature, but know that in doing so you
5811 are taking the risk of using an experimental feature which may
5812 change or be removed in a future Perl version:
5814 no warnings "experimental::lexical_subs";
5815 use feature "lexical_subs";
5818 =item The regex_sets feature is experimental
5820 (S experimental::regex_sets) This warning is emitted if you
5821 use the syntax S<C<(?[ ])>> in a regular expression.
5822 The details of this feature are subject to change.
5823 if you want to use it, but know that in doing so you
5824 are taking the risk of using an experimental feature which may
5825 change in a future Perl version, you can do this to silence the
5828 no warnings "experimental::regex_sets";
5830 =item The signatures feature is experimental
5832 (S experimental::signatures) This warning is emitted if you unwrap a
5833 subroutine's arguments using a signature. Simply suppress the warning
5834 if you want to use the feature, but know that in doing so you are taking
5835 the risk of using an experimental feature which may change or be removed
5836 in a future Perl version:
5838 no warnings "experimental::signatures";
5839 use feature "signatures";
5840 sub foo ($left, $right) { ... }
5842 =item The stat preceding %s wasn't an lstat
5844 (F) It makes no sense to test the current stat buffer for symbolic
5845 linkhood if the last stat that wrote to the stat buffer already went
5846 past the symlink to get to the real file. Use an actual filename
5849 =item The 'unique' attribute may only be applied to 'our' variables
5851 (F) This attribute was never supported on C<my> or C<sub> declarations.
5853 =item This Perl can't reset CRTL environ elements (%s)
5855 =item This Perl can't set CRTL environ elements (%s=%s)
5857 (W internal) Warnings peculiar to VMS. You tried to change or delete an
5858 element of the CRTL's internal environ array, but your copy of Perl
5859 wasn't built with a CRTL that contained the setenv() function. You'll
5860 need to rebuild Perl with a CRTL that does, or redefine
5861 F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
5862 target of the change to
5863 %ENV which produced the warning.
5865 =item This Perl has not been built with support for randomized hash key traversal but something called Perl_hv_rand_set().
5867 (F) Something has attempted to use an internal API call which
5868 depends on Perl being compiled with the default support for randomized hash
5869 key traversal, but this Perl has been compiled without it. You should
5870 report this warning to the relevant upstream party, or recompile perl
5871 with default options.
5873 =item times not implemented
5875 (F) Your version of the C library apparently doesn't do times(). I
5876 suspect you're not running on Unix.
5878 =item "-T" is on the #! line, it must also be used on the command line
5880 (X) The #! line (or local equivalent) in a Perl script contains
5881 the B<-T> option (or the B<-t> option), but Perl was not invoked with
5882 B<-T> in its command line. This is an error because, by the time
5883 Perl discovers a B<-T> in a script, it's too late to properly taint
5884 everything from the environment. So Perl gives up.
5886 If the Perl script is being executed as a command using the #!
5887 mechanism (or its local equivalent), this error can usually be
5888 fixed by editing the #! line so that the B<-%c> option is a part of
5889 Perl's first argument: e.g. change C<perl -n -%c> to C<perl -%c -n>.
5891 If the Perl script is being executed as C<perl scriptname>, then the
5892 B<-%c> option must appear on the command line: C<perl -%c scriptname>.
5894 =item To%s: illegal mapping '%s'
5896 (F) You tried to define a customized To-mapping for lc(), lcfirst,
5897 uc(), or ucfirst() (or their string-inlined versions), but you
5898 specified an illegal mapping.
5899 See L<perlunicode/"User-Defined Character Properties">.
5901 =item Too deeply nested ()-groups
5903 (F) Your template contains ()-groups with a ridiculously deep nesting level.
5905 =item Too few args to syscall
5907 (F) There has to be at least one argument to syscall() to specify the
5908 system call to call, silly dilly.
5910 =item Too few arguments for subroutine
5912 (F) A subroutine using a signature received fewer arguments than required
5913 by the signature. The caller of the subroutine is presumably at fault.
5914 Inconveniently, this error will be reported at the location of the
5915 subroutine, not that of the caller.
5917 =item Too late for "-%s" option
5919 (X) The #! line (or local equivalent) in a Perl script contains the
5920 B<-M>, B<-m> or B<-C> option.
5922 In the case of B<-M> and B<-m>, this is an error because those options
5923 are not intended for use inside scripts. Use the C<use> pragma instead.
5925 The B<-C> option only works if it is specified on the command line as
5926 well (with the same sequence of letters or numbers following). Either
5927 specify this option on the command line, or, if your system supports
5928 it, make your script executable and run it directly instead of passing
5931 =item Too late to run %s block
5933 (W void) A CHECK or INIT block is being defined during run time proper,
5934 when the opportunity to run them has already passed. Perhaps you are
5935 loading a file with C<require> or C<do> when you should be using C<use>
5936 instead. Or perhaps you should put the C<require> or C<do> inside a
5939 =item Too many args to syscall
5941 (F) Perl supports a maximum of only 14 args to syscall().
5943 =item Too many arguments for %s
5945 (F) The function requires fewer arguments than you specified.
5947 =item Too many arguments for subroutine
5949 (F) A subroutine using a signature received more arguments than required
5950 by the signature. The caller of the subroutine is presumably at fault.
5951 Inconveniently, this error will be reported at the location of the
5952 subroutine, not that of the caller.
5956 (A) You've accidentally run your script through B<csh> instead of Perl.
5957 Check the #! line, or manually feed your script into Perl yourself.
5961 (A) You've accidentally run your script through B<csh> instead of Perl.
5962 Check the #! line, or manually feed your script into Perl yourself.
5964 =item Trailing \ in regex m/%s/
5966 (F) The regular expression ends with an unbackslashed backslash.
5967 Backslash it. See L<perlre>.
5969 =item Transliteration pattern not terminated
5971 (F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
5972 or y/// or y[][] construct. Missing the leading C<$> from variables
5973 C<$tr> or C<$y> may cause this error.
5975 =item Transliteration replacement not terminated
5977 (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
5978 y/// or y[][] construct.
5980 =item '%s' trapped by operation mask
5982 (F) You tried to use an operator from a Safe compartment in which it's
5983 disallowed. See L<Safe>.
5985 =item truncate not implemented
5987 (F) Your machine doesn't implement a file truncation mechanism that
5988 Configure knows about.
5990 =item Type of arg %d to &CORE::%s must be %s
5992 (F) The subroutine in question in the CORE package requires its argument
5993 to be a hard reference to data of the specified type. Overloading is
5994 ignored, so a reference to an object that is not the specified type, but
5995 nonetheless has overloading to handle it, will still not be accepted.
5997 =item Type of arg %d to %s must be %s (not %s)
5999 (F) This function requires the argument in that position to be of a
6000 certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
6001 %NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
6002 {EXPR} forms as an explicit dereference. See L<perlref>.
6004 =item umask not implemented
6006 (F) Your machine doesn't implement the umask function and you tried to
6007 use it to restrict permissions for yourself (EXPR & 0700).
6009 =item Unbalanced context: %d more PUSHes than POPs
6011 (S internal) The exit code detected an internal inconsistency in how
6012 many execution contexts were entered and left.
6014 =item Unbalanced saves: %d more saves than restores
6016 (S internal) The exit code detected an internal inconsistency in how
6017 many values were temporarily localized.
6019 =item Unbalanced scopes: %d more ENTERs than LEAVEs
6021 (S internal) The exit code detected an internal inconsistency in how
6022 many blocks were entered and left.
6024 =item Unbalanced string table refcount: (%d) for "%s"
6026 (S internal) On exit, Perl found some strings remaining in the shared
6027 string table used for copy on write and for hash keys. The entries
6028 should have been freed, so this indicates a bug somewhere.
6030 =item Unbalanced tmps: %d more allocs than frees
6032 (S internal) The exit code detected an internal inconsistency in how
6033 many mortal scalars were allocated and freed.
6035 =item Undefined format "%s" called
6037 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6038 another package? See L<perlform>.
6040 =item Undefined sort subroutine "%s" called
6042 (F) The sort comparison routine specified doesn't seem to exist.
6043 Perhaps it's in a different package? See L<perlfunc/sort>.
6045 =item Undefined subroutine &%s called
6047 (F) The subroutine indicated hasn't been defined, or if it was, it has
6048 since been undefined.
6050 =item Undefined subroutine called
6052 (F) The anonymous subroutine you're trying to call hasn't been defined,
6053 or if it was, it has since been undefined.
6055 =item Undefined subroutine in sort
6057 (F) The sort comparison routine specified is declared but doesn't seem
6058 to have been defined yet. See L<perlfunc/sort>.
6060 =item Undefined top format "%s" called
6062 (F) The format indicated doesn't seem to exist. Perhaps it's really in
6063 another package? See L<perlform>.
6065 =item Undefined value assigned to typeglob
6067 (W misc) An undefined value was assigned to a typeglob, a la
6068 C<*foo = undef>. This does nothing. It's possible that you really mean
6071 =item %s: Undefined variable
6073 (A) You've accidentally run your script through B<csh> instead of Perl.
6074 Check the #! line, or manually feed your script into Perl yourself.
6076 =item Unescaped left brace in regex is deprecated, passed through in regex;
6077 marked by S<<-- HERE> in m/%s/
6079 (D deprecated, regexp) You used a literal C<"{"> character in a regular
6080 expression pattern. You should change to use C<"\{"> instead, because a
6081 future version of Perl (tentatively v5.26) will consider this to be a
6082 syntax error. If the pattern delimiters are also braces, any matching
6083 right brace (C<"}">) should also be escaped to avoid confusing the parser,
6088 =item unexec of %s into %s failed!
6090 (F) The unexec() routine failed for some reason. See your local FSF
6091 representative, who probably put it there in the first place.
6093 =item Unexpected binary operator '%c' with no preceding operand in regex;
6094 marked by S<<-- HERE> in m/%s/
6096 (F) You had something like this:
6100 where the C<"|"> is a binary operator with an operand on the right, but
6101 no operand on the left.
6103 =item Unexpected character in regex; marked by S<<-- HERE> in m/%s/
6105 (F) You had something like this:
6109 Within C<(?[ ])>, no literal characters are allowed unless they are
6110 within an inner pair of square brackets, like
6114 Another possibility is that you forgot a backslash. Perl isn't smart
6115 enough to figure out what you really meant.
6117 =item Unexpected constant lvalue entersub entry via type/targ %d:%d
6119 (P) When compiling a subroutine call in lvalue context, Perl failed an
6120 internal consistency check. It encountered a malformed op tree.
6122 =item Unexpected exit %u
6124 (S) exit() was called or the script otherwise finished gracefully when
6125 C<PERL_EXIT_WARN> was set in C<PL_exit_flags>.
6127 =item Unexpected exit failure %d
6129 (S) An uncaught die() was called when C<PERL_EXIT_WARN> was set in
6132 =item Unexpected ')' in regex; marked by S<<-- HERE> in m/%s/
6134 (F) You had something like this:
6136 (?[ ( \p{Digit} + ) ])
6138 The C<")"> is out-of-place. Something apparently was supposed to
6139 be combined with the digits, or the C<"+"> shouldn't be there, or
6140 something like that. Perl can't figure out what was intended.
6142 =item Unexpected '(' with no preceding operator in regex; marked by
6143 S<<-- HERE> in m/%s/
6145 (F) You had something like this:
6147 (?[ \p{Digit} ( \p{Lao} + \p{Thai} ) ])
6149 There should be an operator before the C<"(">, as there's
6150 no indication as to how the digits are to be combined
6151 with the characters in the Lao and Thai scripts.
6153 =item Unicode non-character U+%X is not recommended for open interchange
6155 (S nonchar) Certain codepoints, such as U+FFFE and U+FFFF, are
6156 defined by the Unicode standard to be non-characters. Those
6157 are legal codepoints, but are reserved for internal use; so,
6158 applications shouldn't attempt to exchange them. An application
6159 may not be expecting any of these characters at all, and receiving
6160 them may lead to bugs. If you know what you are doing you can
6161 turn off this warning by C<no warnings 'nonchar';>.
6163 This is not really a "severe" error, but it is supposed to be
6164 raised by default even if warnings are not enabled, and currently
6165 the only way to do that in Perl is to mark it as serious.
6167 =item Unicode surrogate U+%X is illegal in UTF-8
6169 (S surrogate) You had a UTF-16 surrogate in a context where they are
6170 not considered acceptable. These code points, between U+D800 and
6171 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6172 internally allows all unsigned integer code points (up to the size limit
6173 available on your platform), including surrogates. But these can cause
6174 problems when being input or output, which is likely where this message
6175 came from. If you really really know what you are doing you can turn
6176 off this warning by C<no warnings 'surrogate';>.
6178 =item Unknown charname '%s'
6180 (F) The name you used inside C<\N{}> is unknown to Perl. Check the
6181 spelling. You can say C<use charnames ":loose"> to not have to be
6182 so precise about spaces, hyphens, and capitalization on standard Unicode
6183 names. (Any custom aliases that have been created must be specified
6184 exactly, regardless of whether C<:loose> is used or not.) This error may
6185 also happen if the C<\N{}> is not in the scope of the corresponding
6186 C<S<use charnames>>.
6190 (P) Perl was about to print an error message in C<$@>, but the C<$@> variable
6191 did not exist, even after an attempt to create it.
6193 =item Unknown open() mode '%s'
6195 (F) The second argument of 3-argument open() is not among the list
6196 of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
6197 C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
6199 =item Unknown PerlIO layer "%s"
6201 (W layer) An attempt was made to push an unknown layer onto the Perl I/O
6202 system. (Layers take care of transforming data between external and
6203 internal representations.) Note that some layers, such as C<mmap>,
6204 are not supported in all environments. If your program didn't
6205 explicitly request the failing operation, it may be the result of the
6206 value of the environment variable PERLIO.
6208 =item Unknown process %x sent message to prime_env_iter: %s
6210 (P) An error peculiar to VMS. Perl was reading values for %ENV before
6211 iterating over it, and someone else stuck a message in the stream of
6212 data Perl expected. Someone's very confused, or perhaps trying to
6213 subvert Perl's population of %ENV for nefarious purposes.
6215 =item Unknown regex modifier "%s"
6217 (F) Alphanumerics immediately following the closing delimiter
6218 of a regular expression pattern are interpreted by Perl as modifier
6219 flags for the regex. One of the ones you specified is invalid. One way
6220 this can happen is if you didn't put in white space between the end of
6221 the regex and a following alphanumeric operator:
6223 if ($a =~ /foo/and $bar == 3) { ... }
6225 The C<"a"> is a valid modifier flag, but the C<"n"> is not, and raises
6226 this error. Likely what was meant instead was:
6228 if ($a =~ /foo/ and $bar == 3) { ... }
6230 =item Unknown "re" subpragma '%s' (known ones are: %s)
6232 (W) You tried to use an unknown subpragma of the "re" pragma.
6234 =item Unknown switch condition (?(...)) in regex; marked by S<<-- HERE> in
6237 (F) The condition part of a (?(condition)if-clause|else-clause) construct
6238 is not known. The condition must be one of the following:
6240 (1) (2) ... true if 1st, 2nd, etc., capture matched
6241 (<NAME>) ('NAME') true if named capture matched
6242 (?=...) (?<=...) true if subpattern matches
6243 (?!...) (?<!...) true if subpattern fails to match
6244 (?{ CODE }) true if code returns a true value
6245 (R) true if evaluating inside recursion
6246 (R1) (R2) ... true if directly inside capture group 1, 2, etc.
6247 (R&NAME) true if directly inside named capture
6248 (DEFINE) always false; for defining named subpatterns
6250 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6251 discovered. See L<perlre>.
6253 =item Unknown Unicode option letter '%c'
6255 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6256 of the C<-C> switch for the list of known options.
6258 =item Unknown Unicode option value %d
6260 (F) You specified an unknown Unicode option. See L<perlrun> documentation
6261 of the C<-C> switch for the list of known options.
6263 =item Unknown verb pattern '%s' in regex; marked by S<<-- HERE> in m/%s/
6265 (F) You either made a typo or have incorrectly put a C<*> quantifier
6266 after an open brace in your pattern. Check the pattern and review
6267 L<perlre> for details on legal verb patterns.
6269 =item Unknown warnings category '%s'
6271 (F) An error issued by the C<warnings> pragma. You specified a warnings
6272 category that is unknown to perl at this point.
6274 Note that if you want to enable a warnings category registered by a
6275 module (e.g. C<use warnings 'File::Find'>), you must have loaded this
6278 =item Unmatched '[' in POSIX class in regex; marked by S<<-- HERE> in m/%s/
6280 (F) You had something like this:
6284 That should be written:
6288 =item Unmatched '%c' in POSIX class in regex; marked by S<<-- HERE> in
6291 (F) You had something like this:
6295 There should be a second C<":">, like this:
6299 =item Unmatched [ in regex; marked by S<<-- HERE> in m/%s/
6301 (F) The brackets around a character class must match. If you wish to
6302 include a closing bracket in a character class, backslash it or put it
6303 first. The S<<-- HERE> shows whereabouts in the regular expression the
6304 problem was discovered. See L<perlre>.
6306 =item Unmatched ( in regex; marked by S<<-- HERE> in m/%s/
6308 =item Unmatched ) in regex; marked by S<<-- HERE> in m/%s/
6310 (F) Unbackslashed parentheses must always be balanced in regular
6311 expressions. If you're a vi user, the % key is valuable for finding
6312 the matching parenthesis. The S<<-- HERE> shows whereabouts in the
6313 regular expression the problem was discovered. See L<perlre>.
6315 =item Unmatched right %s bracket
6317 (F) The lexer counted more closing curly or square brackets than opening
6318 ones, so you're probably missing a matching opening bracket. As a
6319 general rule, you'll find the missing one (so to speak) near the place
6320 you were last editing.
6322 =item Unquoted string "%s" may clash with future reserved word
6324 (W reserved) You used a bareword that might someday be claimed as a
6325 reserved word. It's best to put such a word in quotes, or capitalize it
6326 somehow, or insert an underbar into it. You might also declare it as a
6329 =item Unrecognized character %s; marked by S<<-- HERE> after %s near column
6332 (F) The Perl parser has no idea what to do with the specified character
6333 in your Perl script (or eval) near the specified column. Perhaps you
6334 tried to run a compressed script, a binary program, or a directory as
6337 =item Unrecognized escape \%c in character class in regex; marked by
6338 S<<-- HERE> in m/%s/
6340 (F) You used a backslash-character combination which is not
6341 recognized by Perl inside character classes. This is a fatal
6342 error when the character class is used within C<(?[ ])>.
6344 =item Unrecognized escape \%c in character class passed through in regex;
6345 marked by S<<-- HERE> in m/%s/
6347 (W regexp) You used a backslash-character combination which is not
6348 recognized by Perl inside character classes. The character was
6349 understood literally, but this may change in a future version of Perl.
6350 The S<<-- HERE> shows whereabouts in the regular expression the
6351 escape was discovered.
6353 =item Unrecognized escape \%c passed through
6355 (W misc) You used a backslash-character combination which is not
6356 recognized by Perl. The character was understood literally, but this may
6357 change in a future version of Perl.
6359 =item Unrecognized escape \%s passed through in regex; marked by
6360 S<<-- HERE> in m/%s/
6362 (W regexp) You used a backslash-character combination which is not
6363 recognized by Perl. The character(s) were understood literally, but
6364 this may change in a future version of Perl. The S<<-- HERE> shows
6365 whereabouts in the regular expression the escape was discovered.
6367 =item Unrecognized signal name "%s"
6369 (F) You specified a signal name to the kill() function that was not
6370 recognized. Say C<kill -l> in your shell to see the valid signal names
6373 =item Unrecognized switch: -%s (-h will show valid options)
6375 (F) You specified an illegal option to Perl. Don't do that. (If you
6376 think you didn't do that, check the #! line to see if it's supplying the
6377 bad switch on your behalf.)
6379 =item Unsuccessful %s on filename containing newline
6381 (W newline) A file operation was attempted on a filename, and that
6382 operation failed, PROBABLY because the filename contained a newline,
6383 PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
6385 =item Unsupported directory function "%s" called
6387 (F) Your machine doesn't support opendir() and readdir().
6389 =item Unsupported function %s
6391 (F) This machine doesn't implement the indicated function, apparently.
6392 At least, Configure doesn't think so.
6394 =item Unsupported function fork
6396 (F) Your version of executable does not support forking.
6398 Note that under some systems, like OS/2, there may be different flavors
6399 of Perl executables, some of which may support fork, some not. Try
6400 changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
6402 =item Unsupported script encoding %s
6404 (F) Your program file begins with a Unicode Byte Order Mark (BOM) which
6405 declares it to be in a Unicode encoding that Perl cannot read.
6407 =item Unsupported socket function "%s" called
6409 (F) Your machine doesn't support the Berkeley socket mechanism, or at
6410 least that's what Configure thought.
6412 =item Unterminated attribute list
6414 (F) The lexer found something other than a simple identifier at the
6415 start of an attribute, and it wasn't a semicolon or the start of a
6416 block. Perhaps you terminated the parameter list of the previous
6417 attribute too soon. See L<attributes>.
6419 =item Unterminated attribute parameter in attribute list
6421 (F) The lexer saw an opening (left) parenthesis character while parsing
6422 an attribute list, but the matching closing (right) parenthesis
6423 character was not found. You may need to add (or remove) a backslash
6424 character to get your parentheses to balance. See L<attributes>.
6426 =item Unterminated compressed integer
6428 (F) An argument to unpack("w",...) was incompatible with the BER
6429 compressed integer format and could not be converted to an integer.
6430 See L<perlfunc/pack>.
6432 =item Unterminated delimiter for here document
6434 (F) This message occurs when a here document label has an initial
6435 quotation mark but the final quotation mark is missing. Perhaps
6444 =item Unterminated \g... pattern in regex; marked by S<<-- HERE> in m/%s/
6446 =item Unterminated \g{...} pattern in regex; marked by S<<-- HERE> in m/%s/
6448 (F) In a regular expression, you had a C<\g> that wasn't followed by a
6449 proper group reference. In the case of C<\g{>, the closing brace is
6450 missing; otherwise the C<\g> must be followed by an integer. Fix the
6453 =item Unterminated <> operator
6455 (F) The lexer saw a left angle bracket in a place where it was expecting
6456 a term, so it's looking for the corresponding right angle bracket, and
6457 not finding it. Chances are you left some needed parentheses out
6458 earlier in the line, and you really meant a "less than".
6460 =item Unterminated verb pattern argument in regex; marked by S<<-- HERE> in
6463 (F) You used a pattern of the form C<(*VERB:ARG)> but did not terminate
6464 the pattern with a C<)>. Fix the pattern and retry.
6466 =item Unterminated verb pattern in regex; marked by S<<-- HERE> in m/%s/
6468 (F) You used a pattern of the form C<(*VERB)> but did not terminate
6469 the pattern with a C<)>. Fix the pattern and retry.
6471 =item untie attempted while %d inner references still exist
6473 (W untie) A copy of the object returned from C<tie> (or C<tied>) was
6474 still valid when C<untie> was called.
6476 =item Usage: POSIX::%s(%s)
6478 (F) You called a POSIX function with incorrect arguments.
6479 See L<POSIX/FUNCTIONS> for more information.
6481 =item Usage: Win32::%s(%s)
6483 (F) You called a Win32 function with incorrect arguments.
6484 See L<Win32> for more information.
6486 =item $[ used in %s (did you mean $] ?)
6488 (W syntax) You used C<$[> in a comparison, such as:
6494 You probably meant to use C<$]> instead. C<$[> is the base for indexing
6495 arrays. C<$]> is the Perl version number in decimal.
6497 =item Use "%s" instead of "%s"
6499 (F) The second listed construct is no longer legal. Use the first one
6502 =item Useless assignment to a temporary
6504 (W misc) You assigned to an lvalue subroutine, but what
6505 the subroutine returned was a temporary scalar about to
6506 be discarded, so the assignment had no effect.
6508 =item Useless (?-%s) - don't use /%s modifier in regex; marked by
6509 S<<-- HERE> in m/%s/
6511 (W regexp) You have used an internal modifier such as (?-o) that has no
6512 meaning unless removed from the entire regexp:
6514 if ($string =~ /(?-o)$pattern/o) { ... }
6518 if ($string =~ /$pattern/) { ... }
6520 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6521 discovered. See L<perlre>.
6523 =item Useless localization of %s
6525 (W syntax) The localization of lvalues such as C<local($x=10)> is legal,
6526 but in fact the local() currently has no effect. This may change at
6527 some point in the future, but in the meantime such code is discouraged.
6529 =item Useless (?%s) - use /%s modifier in regex; marked by S<<-- HERE> in
6532 (W regexp) You have used an internal modifier such as (?o) that has no
6533 meaning unless applied to the entire regexp:
6535 if ($string =~ /(?o)$pattern/) { ... }
6539 if ($string =~ /$pattern/o) { ... }
6541 The S<<-- HERE> shows whereabouts in the regular expression the problem was
6542 discovered. See L<perlre>.
6544 =item Useless use of attribute "const"
6546 (W misc) The C<const> attribute has no effect except
6547 on anonymous closure prototypes. You applied it to
6548 a subroutine via L<attributes.pm|attributes>. This is only useful
6549 inside an attribute handler for an anonymous subroutine.
6551 =item Useless use of /d modifier in transliteration operator
6553 (W misc) You have used the /d modifier where the searchlist has the
6554 same length as the replacelist. See L<perlop> for more information
6555 about the /d modifier.
6557 =item Useless use of \E
6559 (W misc) You have a \E in a double-quotish string without a C<\U>,
6560 C<\L> or C<\Q> preceding it.
6562 =item Useless use of greediness modifier '%c' in regex; marked by S<<-- HERE> in m/%s/
6564 (W regexp) You specified something like these:
6569 The C<"?"> and C<"+"> don't have any effect, as they modify whether to
6570 match more or fewer when there is a choice, and by specifying to match
6571 exactly a given numer, there is no room left for a choice.
6573 =item Useless use of %s in void context
6575 (W void) You did something without a side effect in a context that does
6576 nothing with the return value, such as a statement that doesn't return a
6577 value from a block, or the left side of a scalar comma operator. Very
6578 often this points not to stupidity on your part, but a failure of Perl
6579 to parse your program the way you thought it would. For example, you'd
6580 get this if you mixed up your C precedence with Python precedence and
6585 when you meant to say
6587 ($one, $two) = (1, 2);
6589 Another common error is to use ordinary parentheses to construct a list
6590 reference when you should be using square or curly brackets, for
6595 when you should have said
6599 The square brackets explicitly turn a list value into a scalar value,
6600 while parentheses do not. So when a parenthesized list is evaluated in
6601 a scalar context, the comma is treated like C's comma operator, which
6602 throws away the left argument, which is not what you want. See
6603 L<perlref> for more on this.
6605 This warning will not be issued for numerical constants equal to 0 or 1
6606 since they are often used in statements like
6608 1 while sub_with_side_effects();
6610 String constants that would normally evaluate to 0 or 1 are warned
6613 =item Useless use of (?-p) in regex; marked by S<<-- HERE> in m/%s/
6615 (W regexp) The C<p> modifier cannot be turned off once set. Trying to do
6618 =item Useless use of "re" pragma
6620 (W) You did C<use re;> without any arguments. That isn't very useful.
6622 =item Useless use of sort in scalar context
6624 (W void) You used sort in scalar context, as in :
6628 This is not very useful, and perl currently optimizes this away.
6630 =item Useless use of %s with no values
6632 (W syntax) You used the push() or unshift() function with no arguments
6633 apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
6634 usually have any effect on the array, so is completely useless. It's
6635 possible in principle that push(@tied_array) could have some effect
6636 if the array is tied to a class which implements a PUSH method. If so,
6637 you can write it as C<push(@tied_array,())> to avoid this warning.
6639 =item "use" not allowed in expression
6641 (F) The "use" keyword is recognized and executed at compile time, and
6642 returns no useful value. See L<perlmod>.
6644 =item Use of assignment to $[ is deprecated
6646 (D deprecated) The C<$[> variable (index of the first element in an array)
6647 is deprecated. See L<perlvar/"$[">.
6649 =item Use of bare << to mean <<"" is deprecated
6651 (D deprecated) You are now encouraged to use the explicitly quoted
6652 form if you wish to use an empty line as the terminator of the
6655 =item Use of /c modifier is meaningless in s///
6657 (W regexp) You used the /c modifier in a substitution. The /c
6658 modifier is not presently meaningful in substitutions.
6660 =item Use of /c modifier is meaningless without /g
6662 (W regexp) You used the /c modifier with a regex operand, but didn't
6663 use the /g modifier. Currently, /c is meaningful only when /g is
6664 used. (This may change in the future.)
6666 =item Use of code point 0x%s is deprecated; the permissible max is 0x%s
6668 (D deprecated) You used a code point that will not be allowed in a
6669 future perl version, because it is too large. Unicode only allows code
6670 points up to 0x10FFFF, but Perl allows much larger ones. However, the
6671 largest possible ones break the perl interpreter in some constructs,
6672 including causing it to hang in a few cases. The known problem areas
6673 are in C<tr///>, regular expression pattern matching using quantifiers,
6674 and as the upper limits in loops.
6676 If your code is to run on various platforms, keep in mind that the upper
6677 limit depends on the platform. It is much larger on 64-bit word sizes
6680 =item Use of comma-less variable list is deprecated
6682 (D deprecated) The values you give to a format should be
6683 separated by commas, not just aligned on a line.
6685 =item Use of each() on hash after insertion without resetting hash iterator results in undefined behavior
6687 (S internal) The behavior of C<each()> after insertion is undefined;
6688 it may skip items, or visit items more than once. Consider using
6689 C<keys()> instead of C<each()>.
6691 =item Use of := for an empty attribute list is not allowed
6693 (F) The construction C<my $x := 42> used to parse as equivalent to
6694 C<my $x : = 42> (applying an empty attribute list to C<$x>).
6695 This construct was deprecated in 5.12.0, and has now been made a syntax
6696 error, so C<:=> can be reclaimed as a new operator in the future.
6698 If you need an empty attribute list, for example in a code generator, add
6699 a space before the C<=>.
6701 =item Use of %s for non-UTF-8 locale is wrong. Assuming a UTF-8 locale
6703 (W locale) You are matching a regular expression using locale rules,
6704 and the specified construct was encountered. This construct is only
6705 valid for UTF-8 locales, which the current locale isn't. This doesn't
6706 make sense. Perl will continue, assuming a Unicode (UTF-8) locale, but
6707 the results are likely to be wrong.
6709 =item Use of freed value in iteration
6711 (F) Perhaps you modified the iterated array within the loop?
6712 This error is typically caused by code like the following:
6715 @a = () for (1,2,@a);
6717 You are not supposed to modify arrays while they are being iterated over.
6718 For speed and efficiency reasons, Perl internally does not do full
6719 reference-counting of iterated items, hence deleting such an item in the
6720 middle of an iteration causes Perl to see a freed value.
6722 =item Use of *glob{FILEHANDLE} is deprecated
6724 (D deprecated) You are now encouraged to use the shorter *glob{IO} form
6725 to access the filehandle slot within a typeglob.
6727 =item Use of /g modifier is meaningless in split
6729 (W regexp) You used the /g modifier on the pattern for a C<split>
6730 operator. Since C<split> always tries to match the pattern
6731 repeatedly, the C</g> has no effect.
6733 =item Use of "goto" to jump into a construct is deprecated
6735 (D deprecated) Using C<goto> to jump from an outer scope into an inner
6736 scope is deprecated and should be avoided.
6738 =item Use of inherited AUTOLOAD for non-method %s() is deprecated
6740 (D deprecated) As an (ahem) accidental feature, C<AUTOLOAD>
6741 subroutines are looked up as methods (using the C<@ISA> hierarchy)
6742 even when the subroutines to be autoloaded were called as plain
6743 functions (e.g. C<Foo::bar()>), not as methods (e.g. C<< Foo->bar() >> or
6744 C<< $obj->bar() >>).
6746 This bug will be rectified in future by using method lookup only for
6747 methods' C<AUTOLOAD>s. However, there is a significant base of existing
6748 code that may be using the old behavior. So, as an interim step, Perl
6749 currently issues an optional warning when non-methods use inherited
6752 The simple rule is: Inheritance will not work when autoloading
6753 non-methods. The simple fix for old code is: In any module that used
6754 to depend on inheriting C<AUTOLOAD> for non-methods from a base class
6755 named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
6758 In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
6759 you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
6760 C<use AutoLoader 'AUTOLOAD';>.
6762 =item Use of %s in printf format not supported
6764 (F) You attempted to use a feature of printf that is accessible from
6765 only C. This usually means there's a better way to do it in Perl.
6767 =item Use of %s is deprecated
6769 (D deprecated) The construct indicated is no longer recommended for use,
6770 generally because there's a better way to do it, and also because the
6771 old way has bad side effects.
6773 =item Use of literal control characters in variable names is deprecated
6775 =item Use of literal non-graphic characters in variable names is deprecated
6777 (D deprecated) Using literal non-graphic (including control)
6778 characters in the source to refer to the ^FOO variables, like C<$^X> and
6779 C<${^GLOBAL_PHASE}> is now deprecated. (We use C<^X> and C<^G> here for
6780 legibility. They actually represent the non-printable control
6781 characters, code points 0x18 and 0x07, respectively; C<^A> would mean
6782 the control character whose code point is 0x01.) This only affects
6783 code like C<$\cT>, where C<\cT> is a control in the source code; C<${"\cT"}> and
6784 C<$^T> remain valid. Things that are non-controls and also not graphic
6785 are NO-BREAK SPACE and SOFT HYPHEN, which were previously only allowed
6786 for historical reasons.
6788 =item Use of -l on filehandle%s
6790 (W io) A filehandle represents an opened file, and when you opened the file
6791 it already went past any symlink you are presumably trying to look for.
6792 The operation returned C<undef>. Use a filename instead.
6794 =item Use of %s on a handle without * is deprecated
6796 (D deprecated) You used C<tie>, C<tied> or C<untie> on a scalar but that scalar
6797 happens to hold a typeglob, which means its filehandle will be tied. If
6798 you mean to tie a handle, use an explicit * as in C<tie *$handle>.
6800 This was a long-standing bug that was removed in Perl 5.16, as there was
6801 no way to tie the scalar itself when it held a typeglob, and no way to
6802 untie a scalar that had had a typeglob assigned to it. If you see this
6803 message, you must be using an older version.
6805 =item Use of reference "%s" as array index
6807 (W misc) You tried to use a reference as an array index; this probably
6808 isn't what you mean, because references in numerical context tend
6809 to be huge numbers, and so usually indicates programmer error.
6811 If you really do mean it, explicitly numify your reference, like so:
6812 C<$array[0+$ref]>. This warning is not given for overloaded objects,
6813 however, because you can overload the numification and stringification
6814 operators and then you presumably know what you are doing.
6816 =item Use of state $_ is experimental
6818 (S experimental::lexical_topic) Lexical $_ is an experimental feature and
6819 its behavior may change or even be removed in any future release of perl.
6820 See the explanation under L<perlvar/$_>.
6822 =item Use of strings with code points over 0xFF as arguments to %s
6823 operator is deprecated
6825 (D deprecated) You tried to use one of the string bitwise operators
6826 (C<&> or C<|> or C<^> or C<~>) on a string containing a code point over
6827 0xFF. The string bitwise operators treat their operands as strings of
6828 bytes, and values beyond 0xFF are nonsensical in this context.
6830 =item Use of tainted arguments in %s is deprecated
6832 (W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
6833 arguments and at least one of them is tainted. This used to be allowed
6834 but will become a fatal error in a future version of perl. Untaint your
6835 arguments. See L<perlsec>.
6837 =item Use of uninitialized value%s
6839 (W uninitialized) An undefined value was used as if it were already
6840 defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
6841 To suppress this warning assign a defined value to your variables.
6843 To help you figure out what was undefined, perl will try to tell you
6844 the name of the variable (if any) that was undefined. In some cases
6845 it cannot do this, so it also tells you what operation you used the
6846 undefined value in. Note, however, that perl optimizes your program
6847 and the operation displayed in the warning may not necessarily appear
6848 literally in your program. For example, C<"that $foo"> is usually
6849 optimized into C<"that " . $foo>, and the warning will refer to the
6850 C<concatenation (.)> operator, even though there is no C<.> in
6853 =item "use re 'strict'" is experimental
6855 (S experimental::re_strict) The things that are different when a regular
6856 expression pattern is compiled under C<'strict'> are subject to change
6857 in future Perl releases in incompatible ways. This means that a pattern
6858 that compiles today may not in a future Perl release. This warning is
6859 to alert you to that risk.
6861 =item Use \x{...} for more than two hex characters in regex; marked by
6862 S<<-- HERE> in m/%s/
6864 (F) In a regular expression, you said something like
6868 Perl isn't sure if you meant this
6872 or if you meant this
6874 (?[ [ \x{BE} E F ] ])
6876 You need to add either braces or blanks to disambiguate.
6878 =item Using just the first character returned by \N{} in character class in
6879 regex; marked by S<<-- HERE> in m/%s/
6881 (W regexp) Named Unicode character escapes C<(\N{...})> may return
6882 a multi-character sequence. Even though a character class is
6883 supposed to match just one character of input, perl will match
6884 the whole thing correctly, except when the class is inverted
6885 (C<[^...]>), or the escape is the beginning or final end point of
6886 a range. For these, what should happen isn't clear at all. In
6887 these circumstances, Perl discards all but the first character
6888 of the returned sequence, which is not likely what you want.
6890 =item Using /u for '%s' instead of /%s in regex; marked by S<<-- HERE> in m/%s/
6892 (W regexp) You used a Unicode boundary (C<\b{...}> or C<\B{...}>) in a
6893 portion of a regular expression where the character set modifiers C</a>
6894 or C</aa> are in effect. These two modifiers indicate an ASCII
6895 interpretation, and this doesn't make sense for a Unicode defintion.
6896 The generated regular expression will compile so that the boundary uses
6897 all of Unicode. No other portion of the regular expression is affected.
6899 =item Using !~ with %s doesn't make sense
6901 (F) Using the C<!~> operator with C<s///r>, C<tr///r> or C<y///r> is
6902 currently reserved for future use, as the exact behavior has not
6903 been decided. (Simply returning the boolean opposite of the
6904 modified string is usually not particularly useful.)
6906 =item UTF-16 surrogate U+%X
6908 (S surrogate) You had a UTF-16 surrogate in a context where they are
6909 not considered acceptable. These code points, between U+D800 and
6910 U+DFFF (inclusive), are used by Unicode only for UTF-16. However, Perl
6911 internally allows all unsigned integer code points (up to the size limit
6912 available on your platform), including surrogates. But these can cause
6913 problems when being input or output, which is likely where this message
6914 came from. If you really really know what you are doing you can turn
6915 off this warning by C<no warnings 'surrogate';>.
6917 =item Value of %s can be "0"; test with defined()
6919 (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
6920 C<each()>, or C<readdir()> as a boolean value. Each of these constructs
6921 can return a value of "0"; that would make the conditional expression
6922 false, which is probably not what you intended. When using these
6923 constructs in conditional expressions, test their values with the
6924 C<defined> operator.
6926 =item Value of CLI symbol "%s" too long
6928 (W misc) A warning peculiar to VMS. Perl tried to read the value of an
6929 %ENV element from a CLI symbol table, and found a resultant string
6930 longer than 1024 characters. The return value has been truncated to
6933 =item Variable "%s" is not available
6935 (W closure) During compilation, an inner named subroutine or eval is
6936 attempting to capture an outer lexical that is not currently available.
6937 This can happen for one of two reasons. First, the outer lexical may be
6938 declared in an outer anonymous subroutine that has not yet been created.
6939 (Remember that named subs are created at compile time, while anonymous
6940 subs are created at run-time.) For example,
6942 sub { my $a; sub f { $a } }
6944 At the time that f is created, it can't capture the current value of $a,
6945 since the anonymous subroutine hasn't been created yet. Conversely,
6946 the following won't give a warning since the anonymous subroutine has by
6947 now been created and is live:
6949 sub { my $a; eval 'sub f { $a }' }->();
6951 The second situation is caused by an eval accessing a variable that has
6952 gone out of scope, for example,
6960 Here, when the '$a' in the eval is being compiled, f() is not currently
6961 being executed, so its $a is not available for capture.
6963 =item Variable "%s" is not imported%s
6965 (S misc) With "use strict" in effect, you referred to a global variable
6966 that you apparently thought was imported from another module, because
6967 something else of the same name (usually a subroutine) is exported by
6968 that module. It usually means you put the wrong funny character on the
6969 front of your variable.
6971 =item Variable length lookbehind not implemented in regex m/%s/
6973 (F) Lookbehind is allowed only for subexpressions whose length is fixed and
6974 known at compile time. For positive lookbehind, you can use the C<\K>
6975 regex construct as a way to get the equivalent functionality. See
6976 L<perlre/(?<=pattern) \K>.
6978 There are non-obvious Unicode rules under C</i> that can match variably,
6979 but which you might not think could. For example, the substring C<"ss">
6980 can match the single character LATIN SMALL LETTER SHARP S. There are
6981 other sequences of ASCII characters that can match single ligature
6982 characters, such as LATIN SMALL LIGATURE FFI matching C<qr/ffi/i>.
6983 Starting in Perl v5.16, if you only care about ASCII matches, adding the
6984 C</aa> modifier to the regex will exclude all these non-obvious matches,
6985 thus getting rid of this message. You can also say C<S<use re qw(/aa)>>
6986 to apply C</aa> to all regular expressions compiled within its scope.
6989 =item "%s" variable %s masks earlier declaration in same %s
6991 (W misc) A "my", "our" or "state" variable has been redeclared in the
6992 current scope or statement, effectively eliminating all access to the
6993 previous instance. This is almost always a typographical error. Note
6994 that the earlier variable will still exist until the end of the scope
6995 or until all closure references to it are destroyed.
6997 =item Variable syntax
6999 (A) You've accidentally run your script through B<csh> instead
7000 of Perl. Check the #! line, or manually feed your script into
7003 =item Variable "%s" will not stay shared
7005 (W closure) An inner (nested) I<named> subroutine is referencing a
7006 lexical variable defined in an outer named subroutine.
7008 When the inner subroutine is called, it will see the value of
7009 the outer subroutine's variable as it was before and during the *first*
7010 call to the outer subroutine; in this case, after the first call to the
7011 outer subroutine is complete, the inner and outer subroutines will no
7012 longer share a common value for the variable. In other words, the
7013 variable will no longer be shared.
7015 This problem can usually be solved by making the inner subroutine
7016 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
7017 reference variables in outer subroutines are created, they
7018 are automatically rebound to the current values of such variables.
7020 =item vector argument not supported with alpha versions
7022 (S printf) The %vd (s)printf format does not support version objects
7025 =item Verb pattern '%s' has a mandatory argument in regex; marked by
7026 S<<-- HERE> in m/%s/
7028 (F) You used a verb pattern that requires an argument. Supply an
7029 argument or check that you are using the right verb.
7031 =item Verb pattern '%s' may not have an argument in regex; marked by
7032 S<<-- HERE> in m/%s/
7034 (F) You used a verb pattern that is not allowed an argument. Remove the
7035 argument or check that you are using the right verb.
7037 =item Version number must be a constant number
7039 (P) The attempt to translate a C<use Module n.n LIST> statement into
7040 its equivalent C<BEGIN> block found an internal inconsistency with
7043 =item Version string '%s' contains invalid data; ignoring: '%s'
7045 (W misc) The version string contains invalid characters at the end, which
7048 =item Warning: something's wrong
7050 (W) You passed warn() an empty string (the equivalent of C<warn "">) or
7051 you called it with no args and C<$@> was empty.
7053 =item Warning: unable to close filehandle %s properly
7055 (S) The implicit close() done by an open() got an error indication on
7056 the close(). This usually indicates your file system ran out of disk
7059 =item Warning: unable to close filehandle properly: %s
7061 =item Warning: unable to close filehandle %s properly: %s
7063 (S io) An error occurred when Perl implicitly closed a filehandle. This
7064 usually indicates your file system ran out of disk space.
7066 =item Warning: Use of "%s" without parentheses is ambiguous
7068 (S ambiguous) You wrote a unary operator followed by something that
7069 looks like a binary operator that could also have been interpreted as a
7070 term or unary operator. For instance, if you know that the rand
7071 function has a default argument of 1.0, and you write
7075 you may THINK you wrote the same thing as
7079 but in actual fact, you got
7083 So put in parentheses to say what you really mean.
7085 =item when is experimental
7087 (S experimental::smartmatch) C<when> depends on smartmatch, which is
7088 experimental. Additionally, it has several special cases that may
7089 not be immediately obvious, and their behavior may change or
7090 even be removed in any future release of perl. See the explanation
7091 under L<perlsyn/Experimental Details on given and when>.
7093 =item Wide character in %s
7095 (S utf8) Perl met a wide character (>255) when it wasn't expecting
7096 one. This warning is by default on for I/O (like print). The easiest
7097 way to quiet this warning is simply to add the C<:utf8> layer to the
7098 output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
7099 warning is to add C<no warnings 'utf8';> but that is often closer to
7100 cheating. In general, you are supposed to explicitly mark the
7101 filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
7103 =item Wide character (U+%X) in %s
7105 (W locale) While in a single-byte locale (I<i.e.>, a non-UTF-8
7106 one), a multi-byte character was encountered. Perl considers this
7107 character to be the specified Unicode code point. Combining non-UTF-8
7108 locales and Unicode is dangerous. Almost certainly some characters
7109 will have two different representations. For example, in the ISO 8859-7
7110 (Greek) locale, the code point 0xC3 represents a Capital Gamma. But so
7111 also does 0x393. This will make string comparisons unreliable.
7113 You likely need to figure out how this multi-byte character got mixed up
7114 with your single-byte locale (or perhaps you thought you had a UTF-8
7115 locale, but Perl disagrees).
7117 =item %s() with negative argument
7119 (S misc) Certain operations make no sense with negative arguments.
7120 Warning is given and the operation is not done.
7122 =item Within []-length '%c' not allowed
7124 (F) The count in the (un)pack template may be replaced by C<[TEMPLATE]>
7125 only if C<TEMPLATE> always matches the same amount of packed bytes that
7126 can be determined from the template alone. This is not possible if
7127 it contains any of the codes @, /, U, u, w or a *-length. Redesign
7130 =item write() on closed filehandle %s
7132 (W closed) The filehandle you're writing to got itself closed sometime
7133 before now. Check your control flow.
7135 =item %s "\x%X" does not map to Unicode
7137 (S utf8) When reading in different encodings, Perl tries to
7138 map everything into Unicode characters. The bytes you read
7139 in are not legal in this encoding. For example
7141 utf8 "\xE4" does not map to Unicode
7143 if you try to read in the a-diaereses Latin-1 as UTF-8.
7145 =item 'X' outside of string
7147 (F) You had a (un)pack template that specified a relative position before
7148 the beginning of the string being (un)packed. See L<perlfunc/pack>.
7150 =item 'x' outside of string in unpack
7152 (F) You had a pack template that specified a relative position after
7153 the end of the string being unpacked. See L<perlfunc/pack>.
7155 =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
7157 (F) And you probably never will, because you probably don't have the
7158 sources to your kernel, and your vendor probably doesn't give a rip
7159 about what you want. Your best bet is to put a setuid C wrapper around
7162 =item You need to quote "%s"
7164 (W syntax) You assigned a bareword as a signal handler name.
7165 Unfortunately, you already have a subroutine of that name declared,
7166 which means that Perl 5 will try to call the subroutine when the
7167 assignment is executed, which is probably not what you want. (If it IS
7168 what you want, put an & in front.)
7170 =item Your random numbers are not that random
7172 (F) When trying to initialize the random seed for hashes, Perl could
7173 not get any randomness out of your system. This usually indicates
7174 Something Very Wrong.
7176 =item Zero length \N{} in regex; marked by S<<-- HERE> in m/%s/
7178 (F) Named Unicode character escapes (C<\N{...}>) may return a zero-length
7179 sequence. Such an escape was used in an extended character class, i.e.
7180 C<(?[...])>, which is not permitted. Check that the correct escape has
7181 been used, and the correct charnames handler is in scope. The S<<-- HERE>
7182 shows whereabouts in the regular expression the problem was discovered.
7188 L<warnings>, L<diagnostics>.