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 (optional).
12 (S) A severe warning (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
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<$SIG{__WARN__}>
27 to a reference to a routine that will be called on each warning instead
28 of printing it. See L<perlvar>.
30 Default warnings are always enabled unless they are explicitly disabled
31 with the C<warnings> pragma or the B<-X> switch.
33 Trappable errors may be trapped using the eval operator. See
34 L<perlfunc/eval>. In almost all cases, warnings may be selectively
35 disabled or promoted to fatal errors using the C<warnings> pragma.
38 The messages are in alphabetical order, without regard to upper or
39 lower-case. Some of these messages are generic. Spots that vary are
40 denoted with a %s or other printf-style escape. These escapes are
41 ignored by the alphabetical order, as are all characters other than
42 letters. To look up your message, just ignore anything that is not a
47 =item accept() on closed socket %s
49 (W closed) You tried to do an accept on a closed socket. Did you forget
50 to check the return value of your socket() call? See
53 =item Allocation too large: %lx
55 (X) You can't allocate more than 64K on an MS-DOS machine.
57 =item '%c' allowed only after types %s
59 (F) The modifiers '!', '<' and '>' are allowed in pack() or unpack() only
60 after certain types. See L<perlfunc/pack>.
62 =item Ambiguous call resolved as CORE::%s(), qualify as such or use &
64 (W ambiguous) A subroutine you have declared has the same name as a Perl
65 keyword, and you have used the name without qualification for calling
66 one or the other. Perl decided to call the builtin because the
67 subroutine is not imported.
69 To force interpretation as a subroutine call, either put an ampersand
70 before the subroutine name, or qualify the name with its package.
71 Alternatively, you can import the subroutine (or pretend that it's
72 imported with the C<use subs> pragma).
74 To silently interpret it as the Perl operator, use the C<CORE::> prefix
75 on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
76 to be an object method (see L<perlsub/"Subroutine Attributes"> or
79 =item Ambiguous range in transliteration operator
81 (F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
82 all. To include a C<-> character in a transliteration, put it either
83 first or last. (In the past, C<tr/a-z-0//> was synonymous with
84 C<tr/a-y//>, which was probably not what you would have expected.)
86 =item Ambiguous use of %s resolved as %s
88 (W ambiguous)(S) You said something that may not be interpreted the way
89 you thought. Normally it's pretty easy to disambiguate it by supplying
90 a missing quote, operator, parenthesis pair or declaration.
92 =item '|' and '<' may not both be specified on command line
94 (F) An error peculiar to VMS. Perl does its own command line
95 redirection, and found that STDIN was a pipe, and that you also tried to
96 redirect STDIN using '<'. Only one STDIN stream to a customer, please.
98 =item '|' and '>' may not both be specified on command line
100 (F) An error peculiar to VMS. Perl does its own command line
101 redirection, and thinks you tried to redirect stdout both to a file and
102 into a pipe to another command. You need to choose one or the other,
103 though nothing's stopping you from piping into a program or Perl script
104 which 'splits' output into two streams, such as
106 open(OUT,">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
113 =item Applying %s to %s will act on scalar(%s)
115 (W misc) The pattern match (C<//>), substitution (C<s///>), and
116 transliteration (C<tr///>) operators work on scalar values. If you apply
117 one of them to an array or a hash, it will convert the array or hash to
118 a scalar value -- the length of an array, or the population info of a
119 hash -- and then work on that scalar value. This is probably not what
120 you meant to do. See L<perlfunc/grep> and L<perlfunc/map> for
123 =item Args must match #! line
125 (F) The setuid emulator requires that the arguments Perl was invoked
126 with match the arguments specified on the #! line. Since some systems
127 impose a one-argument limit on the #! line, try combining switches;
128 for example, turn C<-w -U> into C<-wU>.
130 =item Arg too short for msgsnd
132 (F) msgsnd() requires a string at least as long as sizeof(long).
134 =item %s argument is not a HASH or ARRAY element
136 (F) The argument to exists() must be a hash or array element, such as:
141 =item %s argument is not a HASH or ARRAY element or slice
143 (F) The argument to delete() must be either a hash or array element,
149 or a hash or array slice, such as:
151 @foo[$bar, $baz, $xyzzy]
152 @{$ref->[12]}{"susie", "queue"}
154 =item %s argument is not a subroutine name
156 (F) The argument to exists() for C<exists &sub> must be a subroutine
157 name, and not a subroutine call. C<exists &sub()> will generate this
160 =item Argument "%s" isn't numeric%s
162 (W numeric) The indicated string was fed as an argument to an operator
163 that expected a numeric value instead. If you're fortunate the message
164 will identify which operator was so unfortunate.
166 =item Argument list not closed for PerlIO layer "%s"
168 (W layer) When pushing a layer with arguments onto the Perl I/O system you
169 forgot the ) that closes the argument list. (Layers take care of transforming
170 data between external and internal representations.) Perl stopped parsing
171 the layer list at this point and did not attempt to push this layer.
172 If your program didn't explicitly request the failing operation, it may be
173 the result of the value of the environment variable PERLIO.
175 =item Array @%s missing the @ in argument %d of %s()
177 (D deprecated) Really old Perl let you omit the @ on array names in some
178 spots. This is now heavily deprecated.
180 =item assertion botched: %s
182 (P) The malloc package that comes with Perl had an internal failure.
184 =item Assertion failed: file "%s"
186 (P) A general assertion failed. The file in question must be examined.
188 =item Assignment to both a list and a scalar
190 (F) If you assign to a conditional operator, the 2nd and 3rd arguments
191 must either both be scalars or both be lists. Otherwise Perl won't
192 know which context to supply to the right side.
194 =item A thread exited while %d threads were running
196 (W) When using threaded Perl, a thread (not necessarily the main
197 thread) exited while there were still other threads running.
198 Usually it's a good idea to first collect the return values of the
199 created threads by joining them, and only then exit from the main
200 thread. See L<threads>.
202 =item Attempt to access disallowed key '%s' in a restricted hash
204 (F) The failing code has attempted to get or set a key which is not in
205 the current set of allowed keys of a restricted hash.
207 =item Attempt to bless into a reference
209 (F) The CLASSNAME argument to the bless() operator is expected to be
210 the name of the package to bless the resulting object into. You've
211 supplied instead a reference to something: perhaps you wrote
217 bless $self, ref($proto) || $proto;
219 If you actually want to bless into the stringified version
220 of the reference supplied, you need to stringify it yourself, for
223 bless $self, "$proto";
225 =item Attempt to delete disallowed key '%s' from a restricted hash
227 (F) The failing code attempted to delete from a restricted hash a key
228 which is not in its key set.
230 =item Attempt to delete readonly key '%s' from a restricted hash
232 (F) The failing code attempted to delete a key whose value has been
233 declared readonly from a restricted hash.
235 =item Attempt to free non-arena SV: 0x%lx
237 (P internal) All SV objects are supposed to be allocated from arenas
238 that will be garbage collected on exit. An SV was discovered to be
239 outside any of those arenas.
241 =item Attempt to free nonexistent shared string
243 (P internal) Perl maintains a reference counted internal table of
244 strings to optimize the storage and access of hash keys and other
245 strings. This indicates someone tried to decrement the reference count
246 of a string that can no longer be found in the table.
248 =item Attempt to free temp prematurely
250 (W debugging) Mortalized values are supposed to be freed by the
251 free_tmps() routine. This indicates that something else is freeing the
252 SV before the free_tmps() routine gets a chance, which means that the
253 free_tmps() routine will be freeing an unreferenced scalar when it does
256 =item Attempt to free unreferenced glob pointers
258 (P internal) The reference counts got screwed up on symbol aliases.
260 =item Attempt to free unreferenced scalar
262 (W internal) Perl went to decrement the reference count of a scalar to
263 see if it would go to 0, and discovered that it had already gone to 0
264 earlier, and should have been freed, and in fact, probably was freed.
265 This could indicate that SvREFCNT_dec() was called too many times, or
266 that SvREFCNT_inc() was called too few times, or that the SV was
267 mortalized when it shouldn't have been, or that memory has been
270 =item Attempt to join self
272 (F) You tried to join a thread from within itself, which is an
273 impossible task. You may be joining the wrong thread, or you may need
274 to move the join() to some other thread.
276 =item Attempt to pack pointer to temporary value
278 (W pack) You tried to pass a temporary value (like the result of a
279 function, or a computed expression) to the "p" pack() template. This
280 means the result contains a pointer to a location that could become
281 invalid anytime, even before the end of the current statement. Use
282 literals or global values as arguments to the "p" pack() template to
285 =item Attempt to use reference as lvalue in substr
287 (W substr) You supplied a reference as the first argument to substr()
288 used as an lvalue, which is pretty strange. Perhaps you forgot to
289 dereference it first. See L<perlfunc/substr>.
291 =item Bad arg length for %s, is %d, should be %s
293 (F) You passed a buffer of the wrong size to one of msgctl(), semctl()
294 or shmctl(). In C parlance, the correct sizes are, respectively,
295 S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and
296 S<sizeof(struct shmid_ds *)>.
298 =item Bad evalled substitution pattern
300 (F) You've used the C</e> switch to evaluate the replacement for a
301 substitution, but perl found a syntax error in the code to evaluate,
302 most likely an unexpected right brace '}'.
304 =item Bad filehandle: %s
306 (F) A symbol was passed to something wanting a filehandle, but the
307 symbol has no filehandle associated with it. Perhaps you didn't do an
308 open(), or did it in another package.
310 =item Bad free() ignored
312 (S malloc) An internal routine called free() on something that had never
313 been malloc()ed in the first place. Mandatory, but can be disabled by
314 setting environment variable C<PERL_BADFREE> to 0.
316 This message can be seen quite often with DB_File on systems with "hard"
317 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
318 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
322 (P) One of the internal hash routines was passed a null HV pointer.
324 =item Badly placed ()'s
326 (A) You've accidentally run your script through B<csh> instead
327 of Perl. Check the #! line, or manually feed your script into
330 =item Bad name after %s::
332 (F) You started to name a symbol by using a package prefix, and then
333 didn't finish the symbol. In particular, you can't interpolate outside
342 $sym = "mypack::$var";
344 =item Bad realloc() ignored
346 (S malloc) An internal routine called realloc() on something that had
347 never been malloc()ed in the first place. Mandatory, but can be disabled
348 by setting environment variable C<PERL_BADFREE> to 1.
350 =item Bad symbol for array
352 (P) An internal request asked to add an array entry to something that
353 wasn't a symbol table entry.
355 =item Bad symbol for filehandle
357 (P) An internal request asked to add a filehandle entry to something
358 that wasn't a symbol table entry.
360 =item Bad symbol for hash
362 (P) An internal request asked to add a hash entry to something that
363 wasn't a symbol table entry.
365 =item Bareword found in conditional
367 (W bareword) The compiler found a bareword where it expected a
368 conditional, which often indicates that an || or && was parsed as part
369 of the last argument of the previous construct, for example:
373 It may also indicate a misspelled constant that has been interpreted as
376 use constant TYPO => 1;
377 if (TYOP) { print "foo" }
379 The C<strict> pragma is useful in avoiding such errors.
381 =item Bareword "%s" not allowed while "strict subs" in use
383 (F) With "strict subs" in use, a bareword is only allowed as a
384 subroutine identifier, in curly brackets or to the left of the "=>"
385 symbol. Perhaps you need to predeclare a subroutine?
387 =item Bareword "%s" refers to nonexistent package
389 (W bareword) You used a qualified bareword of the form C<Foo::>, but the
390 compiler saw no other uses of that namespace before that point. Perhaps
391 you need to predeclare a package?
393 =item BEGIN failed--compilation aborted
395 (F) An untrapped exception was raised while executing a BEGIN
396 subroutine. Compilation stops immediately and the interpreter is
399 =item BEGIN not safe after errors--compilation aborted
401 (F) Perl found a C<BEGIN {}> subroutine (or a C<use> directive, which
402 implies a C<BEGIN {}>) after one or more compilation errors had already
403 occurred. Since the intended environment for the C<BEGIN {}> could not
404 be guaranteed (due to the errors), and since subsequent code likely
405 depends on its correct operation, Perl just gave up.
407 =item \1 better written as $1
409 (W syntax) Outside of patterns, backreferences live on as variables.
410 The use of backslashes is grandfathered on the right-hand side of a
411 substitution, but stylistically it's better to use the variable form
412 because other Perl programmers will expect it, and it works better if
413 there are more than 9 backreferences.
415 =item Binary number > 0b11111111111111111111111111111111 non-portable
417 (W portable) The binary number you specified is larger than 2**32-1
418 (4294967295) and therefore non-portable between systems. See
419 L<perlport> for more on portability concerns.
421 =item bind() on closed socket %s
423 (W closed) You tried to do a bind on a closed socket. Did you forget to
424 check the return value of your socket() call? See L<perlfunc/bind>.
426 =item binmode() on closed filehandle %s
428 (W unopened) You tried binmode() on a filehandle that was never opened.
429 Check you control flow and number of arguments.
431 =item Bit vector size > 32 non-portable
433 (W portable) Using bit vector sizes larger than 32 is non-portable.
435 =item Bizarre copy of %s in %s
437 (P) Perl detected an attempt to copy an internal value that is not
440 =item Buffer overflow in prime_env_iter: %s
442 (W internal) A warning peculiar to VMS. While Perl was preparing to
443 iterate over %ENV, it encountered a logical name or symbol definition
444 which was too long, so it was truncated to the string shown.
446 =item Callback called exit
448 (F) A subroutine invoked from an external package via call_sv()
449 exited by calling exit.
451 =item %s() called too early to check prototype
453 (W prototype) You've called a function that has a prototype before the
454 parser saw a definition or declaration for it, and Perl could not check
455 that the call conforms to the prototype. You need to either add an
456 early prototype declaration for the subroutine in question, or move the
457 subroutine definition ahead of the call to get proper prototype
458 checking. Alternatively, if you are certain that you're calling the
459 function correctly, you may put an ampersand before the name to avoid
460 the warning. See L<perlsub>.
462 =item Cannot compress integer in pack
464 (F) An argument to pack("w",...) was too large to compress. The BER
465 compressed integer format can only be used with positive integers, and you
466 attempted to compress Infinity or a very large number (> 1e308).
467 See L<perlfunc/pack>.
469 =item Cannot compress negative numbers in pack
471 (F) An argument to pack("w",...) was negative. The BER compressed integer
472 format can only be used with positive integers. See L<perlfunc/pack>.
474 =item Can only compress unsigned integers in pack
476 (F) An argument to pack("w",...) was not an integer. The BER compressed
477 integer format can only be used with positive integers, and you attempted
478 to compress something else. See L<perlfunc/pack>.
480 =item Can't bless non-reference value
482 (F) Only hard references may be blessed. This is how Perl "enforces"
483 encapsulation of objects. See L<perlobj>.
485 =item Can't call method "%s" in empty package "%s"
487 (F) You called a method correctly, and it correctly indicated a package
488 functioning as a class, but that package doesn't have ANYTHING defined
489 in it, let alone methods. See L<perlobj>.
491 =item Can't call method "%s" on an undefined value
493 (F) You used the syntax of a method call, but the slot filled by the
494 object reference or package name contains an undefined value. Something
495 like this will reproduce the error:
498 process $BADREF 1,2,3;
499 $BADREF->process(1,2,3);
501 =item Can't call method "%s" on unblessed reference
503 (F) A method call must know in what package it's supposed to run. It
504 ordinarily finds this out from the object reference you supply, but you
505 didn't supply an object reference in this case. A reference isn't an
506 object reference until it has been blessed. See L<perlobj>.
508 =item Can't call method "%s" without a package or object reference
510 (F) You used the syntax of a method call, but the slot filled by the
511 object reference or package name contains an expression that returns a
512 defined value which is neither an object reference nor a package name.
513 Something like this will reproduce the error:
516 process $BADREF 1,2,3;
517 $BADREF->process(1,2,3);
519 =item Can't chdir to %s
521 (F) You called C<perl -x/foo/bar>, but C</foo/bar> is not a directory
522 that you can chdir to, possibly because it doesn't exist.
524 =item Can't check filesystem of script "%s" for nosuid
526 (P) For some reason you can't check the filesystem of the script for
529 =item Can't coerce array into hash
531 (F) You used an array where a hash was expected, but the array has no
532 information on how to map from keys to array indices. You can do that
533 only with arrays that have a hash reference at index 0.
535 =item Can't coerce %s to integer in %s
537 (F) Certain types of SVs, in particular real symbol table entries
538 (typeglobs), can't be forced to stop being what they are. So you can't
548 but then $foo no longer contains a glob.
550 =item Can't coerce %s to number in %s
552 (F) Certain types of SVs, in particular real symbol table entries
553 (typeglobs), can't be forced to stop being what they are.
555 =item Can't coerce %s to string in %s
557 (F) Certain types of SVs, in particular real symbol table entries
558 (typeglobs), can't be forced to stop being what they are.
560 =item Can't create pipe mailbox
562 (P) An error peculiar to VMS. The process is suffering from exhausted
563 quotas or other plumbing problems.
565 =item Can't declare class for non-scalar %s in "%s"
567 (F) Currently, only scalar variables can be declared with a specific
568 class qualifier in a "my" or "our" declaration. The semantics may be
569 extended for other types of variables in future.
571 =item Can't declare %s in "%s"
573 (F) Only scalar, array, and hash variables may be declared as "my" or
574 "our" variables. They must have ordinary identifiers as names.
576 =item Can't do inplace edit: %s is not a regular file
578 (S inplace) You tried to use the B<-i> switch on a special file, such as
579 a file in /dev, or a FIFO. The file was ignored.
581 =item Can't do inplace edit on %s: %s
583 (S inplace) The creation of the new file failed for the indicated
586 =item Can't do inplace edit without backup
588 (F) You're on a system such as MS-DOS that gets confused if you try
589 reading from a deleted (but still opened) file. You have to say
590 C<-i.bak>, or some such.
592 =item Can't do inplace edit: %s would not be unique
594 (S inplace) Your filesystem does not support filenames longer than 14
595 characters and Perl was unable to create a unique filename during
596 inplace editing with the B<-i> switch. The file was ignored.
598 =item Can't do {n,m} with n > m in regex; marked by <-- HERE in m/%s/
600 (F) Minima must be less than or equal to maxima. If you really want your
601 regexp to match something 0 times, just put {0}. The <-- HERE shows in the
602 regular expression about where the problem was discovered. See L<perlre>.
604 =item Can't do setegid!
606 (P) The setegid() call failed for some reason in the setuid emulator of
609 =item Can't do seteuid!
611 (P) The setuid emulator of suidperl failed for some reason.
613 =item Can't do setuid
615 (F) This typically means that ordinary perl tried to exec suidperl to do
616 setuid emulation, but couldn't exec it. It looks for a name of the form
617 sperl5.000 in the same directory that the perl executable resides under
618 the name perl5.000, typically /usr/local/bin on Unix machines. If the
619 file is there, check the execute permissions. If it isn't, ask your
620 sysadmin why he and/or she removed it.
622 =item Can't do waitpid with flags
624 (F) This machine doesn't have either waitpid() or wait4(), so only
625 waitpid() without flags is emulated.
627 =item Can't emulate -%s on #! line
629 (F) The #! line specifies a switch that doesn't make sense at this
630 point. For example, it'd be kind of silly to put a B<-x> on the #!
633 =item Can't %s %s-endian %ss on this platform
635 (F) Your platform's byte-order is neither big-endian nor little-endian,
636 or it has a very strange pointer size. Packing and unpacking big- or
637 little-endian floating point values and pointers may not be possible.
638 See L<perlfunc/pack>.
640 =item Can't exec "%s": %s
642 (W exec) A system(), exec(), or piped open call could not execute the
643 named program for the indicated reason. Typical reasons include: the
644 permissions were wrong on the file, the file wasn't found in
645 C<$ENV{PATH}>, the executable in question was compiled for another
646 architecture, or the #! line in a script points to an interpreter that
647 can't be run for similar reasons. (Or maybe your system doesn't support
652 (F) Perl was trying to execute the indicated program for you because
653 that's what the #! line said. If that's not what you wanted, you may
654 need to mention "perl" on the #! line somewhere.
656 =item Can't execute %s
658 (F) You used the B<-S> switch, but the copies of the script to execute
659 found in the PATH did not have correct permissions.
661 =item Can't find an opnumber for "%s"
663 (F) A string of a form C<CORE::word> was given to prototype(), but there
664 is no builtin with the name C<word>.
666 =item Can't find %s character property "%s"
668 (F) You used C<\p{}> or C<\P{}> but the character property by that name
669 could not be found. Maybe you misspelled the name of the property
670 (remember that the names of character properties consist only of
671 alphanumeric characters), or maybe you forgot the C<Is> or C<In> prefix?
673 =item Can't find label %s
675 (F) You said to goto a label that isn't mentioned anywhere that it's
676 possible for us to go to. See L<perlfunc/goto>.
678 =item Can't find %s on PATH
680 (F) You used the B<-S> switch, but the script to execute could not be
683 =item Can't find %s on PATH, '.' not in PATH
685 (F) You used the B<-S> switch, but the script to execute could not be
686 found in the PATH, or at least not with the correct permissions. The
687 script exists in the current directory, but PATH prohibits running it.
689 =item Can't find %s property definition %s
691 (F) You may have tried to use C<\p> which means a Unicode property (for
692 example C<\p{Lu}> is all uppercase letters). If you did mean to use a
693 Unicode property, see L<perlunicode> for the list of known properties.
694 If you didn't mean to use a Unicode property, escape the C<\p>, either
695 by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, until
698 =item Can't find string terminator %s anywhere before EOF
700 (F) Perl strings can stretch over multiple lines. This message means
701 that the closing delimiter was omitted. Because bracketed quotes count
702 nesting levels, the following is missing its final parenthesis:
704 print q(The character '(' starts a side comment.);
706 If you're getting this error from a here-document, you may have included
707 unseen whitespace before or after your closing tag. A good programmer's
708 editor will have a way to help you find these characters.
712 (F) A fatal error occurred while trying to fork while opening a
715 =item Can't get filespec - stale stat buffer?
717 (S) A warning peculiar to VMS. This arises because of the difference
718 between access checks under VMS and under the Unix model Perl assumes.
719 Under VMS, access checks are done by filename, rather than by bits in
720 the stat buffer, so that ACLs and other protections can be taken into
721 account. Unfortunately, Perl assumes that the stat buffer contains all
722 the necessary information, and passes it, instead of the filespec, to
723 the access checking routine. It will try to retrieve the filespec using
724 the device name and FID present in the stat buffer, but this works only
725 if you haven't made a subsequent call to the CRTL stat() routine,
726 because the device name is overwritten with each call. If this warning
727 appears, the name lookup failed, and the access checking routine gave up
728 and returned FALSE, just to be conservative. (Note: The access checking
729 routine knows about the Perl C<stat> operator and file tests, so you
730 shouldn't ever see this warning in response to a Perl command; it arises
731 only if some internal code takes stat buffers lightly.)
733 =item Can't get pipe mailbox device name
735 (P) An error peculiar to VMS. After creating a mailbox to act as a
736 pipe, Perl can't retrieve its name for later use.
738 =item Can't get SYSGEN parameter value for MAXBUF
740 (P) An error peculiar to VMS. Perl asked $GETSYI how big you want your
741 mailbox buffers to be, and didn't get an answer.
743 =item Can't "goto" into the middle of a foreach loop
745 (F) A "goto" statement was executed to jump into the middle of a foreach
746 loop. You can't get there from here. See L<perlfunc/goto>.
748 =item Can't "goto" out of a pseudo block
750 (F) A "goto" statement was executed to jump out of what might look like
751 a block, except that it isn't a proper block. This usually occurs if
752 you tried to jump out of a sort() block or subroutine, which is a no-no.
753 See L<perlfunc/goto>.
755 =item Can't goto subroutine from an eval-string
757 (F) The "goto subroutine" call can't be used to jump out of an eval
758 "string". (You can use it to jump out of an eval {BLOCK}, but you
759 probably don't want to.)
761 =item Can't goto subroutine outside a subroutine
763 (F) The deeply magical "goto subroutine" call can only replace one
764 subroutine call for another. It can't manufacture one out of whole
765 cloth. In general you should be calling it out of only an AUTOLOAD
766 routine anyway. See L<perlfunc/goto>.
768 =item Can't ignore signal CHLD, forcing to default
770 (W signal) Perl has detected that it is being run with the SIGCHLD
771 signal (sometimes known as SIGCLD) disabled. Since disabling this
772 signal will interfere with proper determination of exit status of child
773 processes, Perl has reset the signal to its default value. This
774 situation typically indicates that the parent program under which Perl
775 may be running (e.g. cron) is being very careless.
777 =item Can't "last" outside a loop block
779 (F) A "last" statement was executed to break out of the current block,
780 except that there's this itty bitty problem called there isn't a current
781 block. Note that an "if" or "else" block doesn't count as a "loopish"
782 block, as doesn't a block given to sort(), map() or grep(). You can
783 usually double the curlies to get the same effect though, because the
784 inner curlies will be considered a block that loops once. See
787 =item Can't load '%s' for module %s
789 (F) The module you tried to load failed to load a dynamic extension. This
790 may either mean that you upgraded your version of perl to one that is
791 incompatible with your old dynamic extensions (which is known to happen
792 between major versions of perl), or (more likely) that your dynamic
793 extension was build against an older version of the library that is
794 installed on your system. You may need to rebuild your old dynamic
797 =item Can't localize lexical variable %s
799 (F) You used local on a variable name that was previously declared as a
800 lexical variable using "my". This is not allowed. If you want to
801 localize a package variable of the same name, qualify it with the
804 =item Can't localize through a reference
806 (F) You said something like C<local $$ref>, which Perl can't currently
807 handle, because when it goes to restore the old value of whatever $ref
808 pointed to after the scope of the local() is finished, it can't be sure
809 that $ref will still be a reference.
811 =item Can't locate %s
813 (F) You said to C<do> (or C<require>, or C<use>) a file that couldn't be
814 found. Perl looks for the file in all the locations mentioned in @INC,
815 unless the file name included the full path to the file. Perhaps you
816 need to set the PERL5LIB or PERL5OPT environment variable to say where
817 the extra library is, or maybe the script needs to add the library name
818 to @INC. Or maybe you just misspelled the name of the file. See
819 L<perlfunc/require> and L<lib>.
821 =item Can't locate auto/%s.al in @INC
823 (F) A function (or method) was called in a package which allows
824 autoload, but there is no function to autoload. Most probable causes
825 are a misprint in a function/method name or a failure to C<AutoSplit>
826 the file, say, by doing C<make install>.
828 =item Can't locate loadable object for module %s in @INC
830 (F) The module you loaded is trying to load an external library, like
831 for example, C<foo.so> or C<bar.dll>, but the L<DynaLoader> module was
832 unable to locate this library. See L<DynaLoader>.
834 =item Can't locate object method "%s" via package "%s"
836 (F) You called a method correctly, and it correctly indicated a package
837 functioning as a class, but that package doesn't define that particular
838 method, nor does any of its base classes. See L<perlobj>.
840 =item Can't locate package %s for @%s::ISA
842 (W syntax) The @ISA array contained the name of another package that
843 doesn't seem to exist.
845 =item Can't locate PerlIO%s
847 (F) You tried to use in open() a PerlIO layer that does not exist,
848 e.g. open(FH, ">:nosuchlayer", "somefile").
850 =item Can't make list assignment to \%ENV on this system
852 (F) List assignment to %ENV is not supported on some systems, notably
855 =item Can't modify %s in %s
857 (F) You aren't allowed to assign to the item indicated, or otherwise try
858 to change it, such as with an auto-increment.
860 =item Can't modify nonexistent substring
862 (P) The internal routine that does assignment to a substr() was handed
865 =item Can't modify non-lvalue subroutine call
867 (F) Subroutines meant to be used in lvalue context should be declared as
868 such, see L<perlsub/"Lvalue subroutines">.
870 =item Can't msgrcv to read-only var
872 (F) The target of a msgrcv must be modifiable to be used as a receive
875 =item Can't "next" outside a loop block
877 (F) A "next" statement was executed to reiterate the current block, but
878 there isn't a current block. Note that an "if" or "else" block doesn't
879 count as a "loopish" block, as doesn't a block given to sort(), map() or
880 grep(). You can usually double the curlies to get the same effect
881 though, because the inner curlies will be considered a block that loops
882 once. See L<perlfunc/next>.
884 =item Can't open %s: %s
886 (S inplace) The implicit opening of a file through use of the C<< <> >>
887 filehandle, either implicitly under the C<-n> or C<-p> command-line
888 switches, or explicitly, failed for the indicated reason. Usually this
889 is because you don't have read permission for a file which you named on
892 =item Can't open a reference
894 (W io) You tried to open a scalar reference for reading or writing,
895 using the 3-arg open() syntax :
899 but your version of perl is compiled without perlio, and this form of
900 open is not supported.
902 =item Can't open bidirectional pipe
904 (W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
905 You can try any of several modules in the Perl library to do this, such
906 as IPC::Open2. Alternately, direct the pipe's output to a file using
907 ">", and then read it in under a different file handle.
909 =item Can't open error file %s as stderr
911 (F) An error peculiar to VMS. Perl does its own command line
912 redirection, and couldn't open the file specified after '2>' or '2>>' on
913 the command line for writing.
915 =item Can't open input file %s as stdin
917 (F) An error peculiar to VMS. Perl does its own command line
918 redirection, and couldn't open the file specified after '<' on the
919 command line for reading.
921 =item Can't open output file %s as stdout
923 (F) An error peculiar to VMS. Perl does its own command line
924 redirection, and couldn't open the file specified after '>' or '>>' on
925 the command line for writing.
927 =item Can't open output pipe (name: %s)
929 (P) An error peculiar to VMS. Perl does its own command line
930 redirection, and couldn't open the pipe into which to send data destined
933 =item Can't open perl script%s
935 (F) The script you specified can't be opened for the indicated reason.
937 =item Can't read CRTL environ
939 (S) A warning peculiar to VMS. Perl tried to read an element of %ENV
940 from the CRTL's internal environment array and discovered the array was
941 missing. You need to figure out where your CRTL misplaced its environ
942 or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not
945 =item Can't redefine active sort subroutine %s
947 (F) Perl optimizes the internal handling of sort subroutines and keeps
948 pointers into them. You tried to redefine one such sort subroutine when
949 it was currently active, which is not allowed. If you really want to do
950 this, you should write C<sort { &func } @x> instead of C<sort func @x>.
952 =item Can't "redo" outside a loop block
954 (F) A "redo" statement was executed to restart the current block, but
955 there isn't a current block. Note that an "if" or "else" block doesn't
956 count as a "loopish" block, as doesn't a block given to sort(), map()
957 or grep(). You can usually double the curlies to get the same effect
958 though, because the inner curlies will be considered a block that
959 loops once. See L<perlfunc/redo>.
961 =item Can't remove %s: %s, skipping file
963 (S inplace) You requested an inplace edit without creating a backup
964 file. Perl was unable to remove the original file to replace it with
965 the modified file. The file was left unmodified.
967 =item Can't rename %s to %s: %s, skipping file
969 (S inplace) The rename done by the B<-i> switch failed for some reason,
970 probably because you don't have write permission to the directory.
972 =item Can't reopen input pipe (name: %s) in binary mode
974 (P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried
975 to reopen it to accept binary data. Alas, it failed.
977 =item Can't resolve method `%s' overloading `%s' in package `%s'
979 (F|P) Error resolving overloading specified by a method name (as opposed
980 to a subroutine reference): no such method callable via the package. If
981 method name is C<???>, this is an internal error.
983 =item Can't reswap uid and euid
985 (P) The setreuid() call failed for some reason in the setuid emulator of
988 =item Can't return %s from lvalue subroutine
990 (F) Perl detected an attempt to return illegal lvalues (such as
991 temporary or readonly values) from a subroutine used as an lvalue. This
994 =item Can't return outside a subroutine
996 (F) The return statement was executed in mainline code, that is, where
997 there was no subroutine call to return out of. See L<perlsub>.
999 =item Can't return %s to lvalue scalar context
1001 (F) You tried to return a complete array or hash from an lvalue subroutine,
1002 but you called the subroutine in a way that made Perl think you meant
1003 to return only one value. You probably meant to write parentheses around
1004 the call to the subroutine, which tell Perl that the call should be in
1007 =item Can't stat script "%s"
1009 (P) For some reason you can't fstat() the script even though you have it
1010 open already. Bizarre.
1012 =item Can't swap uid and euid
1014 (P) The setreuid() call failed for some reason in the setuid emulator of
1017 =item Can't take log of %g
1019 (F) For ordinary real numbers, you can't take the logarithm of a
1020 negative number or zero. There's a Math::Complex package that comes
1021 standard with Perl, though, if you really want to do that for the
1024 =item Can't take sqrt of %g
1026 (F) For ordinary real numbers, you can't take the square root of a
1027 negative number. There's a Math::Complex package that comes standard
1028 with Perl, though, if you really want to do that.
1030 =item Can't undef active subroutine
1032 (F) You can't undefine a routine that's currently running. You can,
1033 however, redefine it while it's running, and you can even undef the
1034 redefined subroutine while the old routine is running. Go figure.
1038 (F) You tried to unshift an "unreal" array that can't be unshifted, such
1039 as the main Perl stack.
1041 =item Can't upgrade that kind of scalar
1043 (P) The internal sv_upgrade routine adds "members" to an SV, making it
1044 into a more specialized kind of SV. The top several SV types are so
1045 specialized, however, that they cannot be interconverted. This message
1046 indicates that such a conversion was attempted.
1048 =item Can't upgrade to undef
1050 (P) The undefined SV is the bottom of the totem pole, in the scheme of
1051 upgradability. Upgrading to undef indicates an error in the code
1054 =item Can't use '%c' in a group with different byte-order in %s
1056 (F) You attempted to force a different byte-order on a type
1057 that is already inside a group with a byte-order modifier.
1058 For example you cannot force little-endianness on a type that
1059 is inside a big-endian group.
1061 =item Can't use anonymous symbol table for method lookup
1063 (F) The internal routine that does method lookup was handed a symbol
1064 table that doesn't have a name. Symbol tables can become anonymous
1065 for example by undefining stashes: C<undef %Some::Package::>.
1067 =item Can't use an undefined value as %s reference
1069 (F) A value used as either a hard reference or a symbolic reference must
1070 be a defined value. This helps to delurk some insidious errors.
1072 =item Can't use bareword ("%s") as %s ref while "strict refs" in use
1074 (F) Only hard references are allowed by "strict refs". Symbolic
1075 references are disallowed. See L<perlref>.
1077 =item Can't use %! because Errno.pm is not available
1079 (F) The first time the %! hash is used, perl automatically loads the
1080 Errno.pm module. The Errno module is expected to tie the %! hash to
1081 provide symbolic names for C<$!> errno values.
1083 =item Can't use both '<' and '>' after type '%c' in %s
1085 (F) A type cannot be forced to have both big-endian and little-endian
1086 byte-order at the same time, so this combination of modifiers is not
1087 allowed. See L<perlfunc/pack>.
1089 =item Can't use %s for loop variable
1091 (F) Only a simple scalar variable may be used as a loop variable on a
1094 =item Can't use global %s in "my"
1096 (F) You tried to declare a magical variable as a lexical variable. This
1097 is not allowed, because the magic can be tied to only one location
1098 (namely the global variable) and it would be incredibly confusing to
1099 have variables in your program that looked like magical variables but
1102 =item Can't use "my %s" in sort comparison
1104 (F) The global variables $a and $b are reserved for sort comparisons.
1105 You mentioned $a or $b in the same line as the <=> or cmp operator,
1106 and the variable had earlier been declared as a lexical variable.
1107 Either qualify the sort variable with the package name, or rename the
1110 =item Can't use %s ref as %s ref
1112 (F) You've mixed up your reference types. You have to dereference a
1113 reference of the type needed. You can use the ref() function to
1114 test the type of the reference, if need be.
1116 =item Can't use string ("%s") as %s ref while "strict refs" in use
1118 (F) Only hard references are allowed by "strict refs". Symbolic
1119 references are disallowed. See L<perlref>.
1121 =item Can't use subscript on %s
1123 (F) The compiler tried to interpret a bracketed expression as a
1124 subscript. But to the left of the brackets was an expression that
1125 didn't look like an array reference, or anything else subscriptable.
1127 =item Can't use \%c to mean $%c in expression
1129 (W syntax) In an ordinary expression, backslash is a unary operator that
1130 creates a reference to its argument. The use of backslash to indicate a
1131 backreference to a matched substring is valid only as part of a regular
1132 expression pattern. Trying to do this in ordinary Perl code produces a
1133 value that prints out looking like SCALAR(0xdecaf). Use the $1 form
1136 =item Can't weaken a nonreference
1138 (F) You attempted to weaken something that was not a reference. Only
1139 references can be weakened.
1141 =item Can't x= to read-only value
1143 (F) You tried to repeat a constant value (often the undefined value)
1144 with an assignment operator, which implies modifying the value itself.
1145 Perhaps you need to copy the value to a temporary, and repeat that.
1147 =item Character in "C" format wrapped in pack
1153 where $x is either less than 0 or more than 255; the C<"C"> format is
1154 only for encoding native operating system characters (ASCII, EBCDIC,
1155 and so on) and not for Unicode characters, so Perl behaved as if you meant
1159 If you actually want to pack Unicode codepoints, use the C<"U"> format
1162 =item Character in "c" format wrapped in pack
1168 where $x is either less than -128 or more than 127; the C<"c"> format
1169 is only for encoding native operating system characters (ASCII, EBCDIC,
1170 and so on) and not for Unicode characters, so Perl behaved as if you meant
1172 pack("c", $x & 255);
1174 If you actually want to pack Unicode codepoints, use the C<"U"> format
1177 =item close() on unopened filehandle %s
1179 (W unopened) You tried to close a filehandle that was never opened.
1181 =item Code missing after '/'
1183 (F) You had a (sub-)template that ends with a '/'. There must be another
1184 template code following the slash. See L<perlfunc/pack>.
1186 =item %s: Command not found
1188 (A) You've accidentally run your script through B<csh> instead of Perl.
1189 Check the #! line, or manually feed your script into Perl yourself.
1191 =item Compilation failed in require
1193 (F) Perl could not compile a file specified in a C<require> statement.
1194 Perl uses this generic message when none of the errors that it
1195 encountered were severe enough to halt compilation immediately.
1197 =item Complex regular subexpression recursion limit (%d) exceeded
1199 (W regexp) The regular expression engine uses recursion in complex
1200 situations where back-tracking is required. Recursion depth is limited
1201 to 32766, or perhaps less in architectures where the stack cannot grow
1202 arbitrarily. ("Simple" and "medium" situations are handled without
1203 recursion and are not subject to a limit.) Try shortening the string
1204 under examination; looping in Perl code (e.g. with C<while>) rather than
1205 in the regular expression engine; or rewriting the regular expression so
1206 that it is simpler or backtracks less. (See L<perlfaq2> for information
1207 on I<Mastering Regular Expressions>.)
1209 =item cond_broadcast() called on unlocked variable
1211 (W threads) Within a thread-enabled program, you tried to call
1212 cond_broadcast() on a variable which wasn't locked. The cond_broadcast()
1213 function is used to wake up another thread that is waiting in a
1214 cond_wait(). To ensure that the signal isn't sent before the other thread
1215 has a chance to enter the wait, it is usual for the signaling thread to
1216 first wait for a lock on variable. This lock attempt will only succeed
1217 after the other thread has entered cond_wait() and thus relinquished the
1220 =item cond_signal() called on unlocked variable
1222 (W threads) Within a thread-enabled program, you tried to call
1223 cond_signal() on a variable which wasn't locked. The cond_signal()
1224 function is used to wake up another thread that is waiting in a
1225 cond_wait(). To ensure that the signal isn't sent before the other thread
1226 has a chance to enter the wait, it is usual for the signaling thread to
1227 first wait for a lock on variable. This lock attempt will only succeed
1228 after the other thread has entered cond_wait() and thus relinquished the
1231 =item connect() on closed socket %s
1233 (W closed) You tried to do a connect on a closed socket. Did you forget
1234 to check the return value of your socket() call? See
1235 L<perlfunc/connect>.
1237 =item Constant(%s)%s: %s
1239 (F) The parser found inconsistencies either while attempting to define
1240 an overloaded constant, or when trying to find the character name
1241 specified in the C<\N{...}> escape. Perhaps you forgot to load the
1242 corresponding C<overload> or C<charnames> pragma? See L<charnames> and
1245 =item Constant is not %s reference
1247 (F) A constant value (perhaps declared using the C<use constant> pragma)
1248 is being dereferenced, but it amounts to the wrong type of reference.
1249 The message indicates the type of reference that was expected. This
1250 usually indicates a syntax error in dereferencing the constant value.
1251 See L<perlsub/"Constant Functions"> and L<constant>.
1253 =item Constant subroutine %s redefined
1255 (S) You redefined a subroutine which had previously been
1256 eligible for inlining. See L<perlsub/"Constant Functions"> for
1257 commentary and workarounds.
1259 =item Constant subroutine %s undefined
1261 (W misc) You undefined a subroutine which had previously been eligible
1262 for inlining. See L<perlsub/"Constant Functions"> for commentary and
1265 =item Copy method did not return a reference
1267 (F) The method which overloads "=" is buggy. See
1268 L<overload/Copy Constructor>.
1270 =item CORE::%s is not a keyword
1272 (F) The CORE:: namespace is reserved for Perl keywords.
1274 =item corrupted regexp pointers
1276 (P) The regular expression engine got confused by what the regular
1277 expression compiler gave it.
1279 =item corrupted regexp program
1281 (P) The regular expression engine got passed a regexp program without a
1284 =item Corrupt malloc ptr 0x%lx at 0x%lx
1286 (P) The malloc package that comes with Perl had an internal failure.
1288 =item Count after length/code in unpack
1290 (F) You had an unpack template indicating a counted-length string, but
1291 you have also specified an explicit size for the string. See
1294 =item Deep recursion on subroutine "%s"
1296 (W recursion) This subroutine has called itself (directly or indirectly)
1297 100 times more than it has returned. This probably indicates an
1298 infinite recursion, unless you're writing strange benchmark programs, in
1299 which case it indicates something else.
1301 =item defined(@array) is deprecated
1303 (D deprecated) defined() is not usually useful on arrays because it
1304 checks for an undefined I<scalar> value. If you want to see if the
1305 array is empty, just use C<if (@array) { # not empty }> for example.
1307 =item defined(%hash) is deprecated
1309 (D deprecated) defined() is not usually useful on hashes because it
1310 checks for an undefined I<scalar> value. If you want to see if the hash
1311 is empty, just use C<if (%hash) { # not empty }> for example.
1313 =item %s defines neither package nor VERSION--version check failed
1315 (F) You said something like "use Module 42" but in the Module file
1316 there are neither package declarations nor a C<$VERSION>.
1318 =item Delimiter for here document is too long
1320 (F) In a here document construct like C<<<FOO>, the label C<FOO> is too
1321 long for Perl to handle. You have to be seriously twisted to write code
1322 that triggers this error.
1324 =item DESTROY created new reference to dead object '%s'
1326 (F) A DESTROY() method created a new reference to the object which is
1327 just being DESTROYed. Perl is confused, and prefers to abort rather than
1328 to create a dangling reference.
1330 =item Did not produce a valid header
1334 =item %s did not return a true value
1336 (F) A required (or used) file must return a true value to indicate that
1337 it compiled correctly and ran its initialization code correctly. It's
1338 traditional to end such a file with a "1;", though any true value would
1339 do. See L<perlfunc/require>.
1341 =item (Did you mean &%s instead?)
1343 (W) You probably referred to an imported subroutine &FOO as $FOO or some
1346 =item (Did you mean "local" instead of "our"?)
1348 (W misc) Remember that "our" does not localize the declared global
1349 variable. You have declared it again in the same lexical scope, which
1352 =item (Did you mean $ or @ instead of %?)
1354 (W) You probably said %hash{$key} when you meant $hash{$key} or
1355 @hash{@keys}. On the other hand, maybe you just meant %hash and got
1360 (F) You passed die() an empty string (the equivalent of C<die "">) or
1361 you called it with no args and both C<$@> and C<$_> were empty.
1363 =item Document contains no data
1367 =item %s does not define %s::VERSION--version check failed
1369 (F) You said something like "use Module 42" but the Module did not
1370 define a C<$VERSION.>
1372 =item '/' does not take a repeat count
1374 (F) You cannot put a repeat count of any kind right after the '/' code.
1375 See L<perlfunc/pack>.
1377 =item Don't know how to handle magic of type '%s'
1379 (P) The internal handling of magical variables has been cursed.
1381 =item do_study: out of memory
1383 (P) This should have been caught by safemalloc() instead.
1385 =item (Do you need to predeclare %s?)
1387 (S syntax) This is an educated guess made in conjunction with the message
1388 "%s found where operator expected". It often means a subroutine or module
1389 name is being referenced that hasn't been declared yet. This may be
1390 because of ordering problems in your file, or because of a missing
1391 "sub", "package", "require", or "use" statement. If you're referencing
1392 something that isn't defined yet, you don't actually have to define the
1393 subroutine or package before the current location. You can use an empty
1394 "sub foo;" or "package FOO;" to enter a "forward" declaration.
1396 =item dump() better written as CORE::dump()
1398 (W misc) You used the obsolescent C<dump()> built-in function, without fully
1399 qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
1401 =item Duplicate free() ignored
1403 (S malloc) An internal routine called free() on something that had
1406 =item Duplicate modifier '%c' after '%c' in %s
1408 (W) You have applied the same modifier more than once after a type
1409 in a pack template. See L<perlfunc/pack>.
1411 =item elseif should be elsif
1413 (S syntax) There is no keyword "elseif" in Perl because Larry thinks it's
1414 ugly. Your code will be interpreted as an attempt to call a method named
1415 "elseif" for the class returned by the following block. This is
1416 unlikely to be what you want.
1420 (F) C<\p> and C<\P> are used to introduce a named Unicode property, as
1421 described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
1422 a regular expression without specifying the property name.
1424 =item entering effective %s failed
1426 (F) While under the C<use filetest> pragma, switching the real and
1427 effective uids or gids failed.
1429 =item %ENV is aliased to %s
1431 (F) You're running under taint mode, and the C<%ENV> variable has been
1432 aliased to another hash, so it doesn't reflect anymore the state of the
1433 program's environment. This is potentially insecure.
1435 =item Error converting file specification %s
1437 (F) An error peculiar to VMS. Because Perl may have to deal with file
1438 specifications in either VMS or Unix syntax, it converts them to a
1439 single form when it must operate on them directly. Either you've passed
1440 an invalid file specification to Perl, or you've found a case the
1441 conversion routines don't handle. Drat.
1443 =item %s: Eval-group in insecure regular expression
1445 (F) Perl detected tainted data when trying to compile a regular
1446 expression that contains the C<(?{ ... })> zero-width assertion, which
1447 is unsafe. See L<perlre/(?{ code })>, and L<perlsec>.
1449 =item %s: Eval-group not allowed at run time
1451 (F) Perl tried to compile a regular expression containing the
1452 C<(?{ ... })> zero-width assertion at run time, as it would when the
1453 pattern contains interpolated values. Since that is a security risk, it
1454 is not allowed. If you insist, you may still do this by explicitly
1455 building the pattern from an interpolated string at run time and using
1456 that in an eval(). See L<perlre/(?{ code })>.
1458 =item %s: Eval-group not allowed, use re 'eval'
1460 (F) A regular expression contained the C<(?{ ... })> zero-width
1461 assertion, but that construct is only allowed when the C<use re 'eval'>
1462 pragma is in effect. See L<perlre/(?{ code })>.
1464 =item Excessively long <> operator
1466 (F) The contents of a <> operator may not exceed the maximum size of a
1467 Perl identifier. If you're just trying to glob a long list of
1468 filenames, try using the glob() operator, or put the filenames into a
1469 variable and glob that.
1471 =item exec? I'm not *that* kind of operating system
1473 (F) The C<exec> function is not implemented in MacPerl. See L<perlport>.
1475 =item Execution of %s aborted due to compilation errors
1477 (F) The final summary message when a Perl compilation fails.
1479 =item Exiting eval via %s
1481 (W exiting) You are exiting an eval by unconventional means, such as a
1482 goto, or a loop control statement.
1484 =item Exiting format via %s
1486 (W exiting) You are exiting a format by unconventional means, such as a
1487 goto, or a loop control statement.
1489 =item Exiting pseudo-block via %s
1491 (W exiting) You are exiting a rather special block construct (like a
1492 sort block or subroutine) by unconventional means, such as a goto, or a
1493 loop control statement. See L<perlfunc/sort>.
1495 =item Exiting subroutine via %s
1497 (W exiting) You are exiting a subroutine by unconventional means, such
1498 as a goto, or a loop control statement.
1500 =item Exiting substitution via %s
1502 (W exiting) You are exiting a substitution by unconventional means, such
1503 as a return, a goto, or a loop control statement.
1505 =item Explicit blessing to '' (assuming package main)
1507 (W misc) You are blessing a reference to a zero length string. This has
1508 the effect of blessing the reference into the package main. This is
1509 usually not what you want. Consider providing a default target package,
1510 e.g. bless($ref, $p || 'MyPackage');
1512 =item %s: Expression syntax
1514 (A) You've accidentally run your script through B<csh> instead of Perl.
1515 Check the #! line, or manually feed your script into Perl yourself.
1517 =item %s failed--call queue aborted
1519 (F) An untrapped exception was raised while executing a CHECK, INIT, or
1520 END subroutine. Processing of the remainder of the queue of such
1521 routines has been prematurely ended.
1523 =item False [] range "%s" in regex; marked by <-- HERE in m/%s/
1525 (W regexp) A character class range must start and end at a literal
1526 character, not another character class like C<\d> or C<[:alpha:]>. The "-"
1527 in your false range is interpreted as a literal "-". Consider quoting the
1528 "-", "\-". The <-- HERE shows in the regular expression about where the
1529 problem was discovered. See L<perlre>.
1531 =item Fatal VMS error at %s, line %d
1533 (P) An error peculiar to VMS. Something untoward happened in a VMS
1534 system service or RTL routine; Perl's exit status should provide more
1535 details. The filename in "at %s" and the line number in "line %d" tell
1536 you which section of the Perl source code is distressed.
1538 =item fcntl is not implemented
1540 (F) Your machine apparently doesn't implement fcntl(). What is this, a
1541 PDP-11 or something?
1543 =item Filehandle %s opened only for input
1545 (W io) You tried to write on a read-only filehandle. If you intended
1546 it to be a read-write filehandle, you needed to open it with "+<" or
1547 "+>" or "+>>" instead of with "<" or nothing. If you intended only to
1548 write the file, use ">" or ">>". See L<perlfunc/open>.
1550 =item Filehandle %s opened only for output
1552 (W io) You tried to read from a filehandle opened only for writing, If
1553 you intended it to be a read/write filehandle, you needed to open it
1554 with "+<" or "+>" or "+>>" instead of with "<" or nothing. If you
1555 intended only to read from the file, use "<". See L<perlfunc/open>.
1556 Another possibility is that you attempted to open filedescriptor 0
1557 (also known as STDIN) for output (maybe you closed STDIN earlier?).
1559 =item Filehandle %s reopened as %s only for input
1561 (W io) You opened for reading a filehandle that got the same filehandle id
1562 as STDOUT or STDERR. This occured because you closed STDOUT or STDERR
1565 =item Filehandle STDIN reopened as %s only for output
1567 (W io) You opened for writing a filehandle that got the same filehandle id
1568 as STDIN. This occured because you closed STDIN previously.
1570 =item Final $ should be \$ or $name
1572 (F) You must now decide whether the final $ in a string was meant to be
1573 a literal dollar sign, or was meant to introduce a variable name that
1574 happens to be missing. So you have to put either the backslash or the
1577 =item flock() on closed filehandle %s
1579 (W closed) The filehandle you're attempting to flock() got itself closed
1580 some time before now. Check your control flow. flock() operates on
1581 filehandles. Are you attempting to call flock() on a dirhandle by the
1584 =item Format not terminated
1586 (F) A format must be terminated by a line with a solitary dot. Perl got
1587 to the end of your file without finding such a line.
1589 =item Format %s redefined
1591 (W redefine) You redefined a format. To suppress this warning, say
1594 no warnings 'redefine';
1595 eval "format NAME =...";
1598 =item Found = in conditional, should be ==
1608 (or something like that).
1610 =item %s found where operator expected
1612 (S syntax) The Perl lexer knows whether to expect a term or an operator.
1613 If it sees what it knows to be a term when it was expecting to see an
1614 operator, it gives you this warning. Usually it indicates that an
1615 operator or delimiter was omitted, such as a semicolon.
1617 =item gdbm store returned %d, errno %d, key "%s"
1619 (S) A warning from the GDBM_File extension that a store failed.
1621 =item gethostent not implemented
1623 (F) Your C library apparently doesn't implement gethostent(), probably
1624 because if it did, it'd feel morally obligated to return every hostname
1627 =item get%sname() on closed socket %s
1629 (W closed) You tried to get a socket or peer socket name on a closed
1630 socket. Did you forget to check the return value of your socket() call?
1632 =item getpwnam returned invalid UIC %#o for user "%s"
1634 (S) A warning peculiar to VMS. The call to C<sys$getuai> underlying the
1635 C<getpwnam> operator returned an invalid UIC.
1637 =item getsockopt() on closed socket %s
1639 (W closed) You tried to get a socket option on a closed socket. Did you
1640 forget to check the return value of your socket() call? See
1641 L<perlfunc/getsockopt>.
1643 =item Global symbol "%s" requires explicit package name
1645 (F) You've said "use strict vars", which indicates that all variables
1646 must either be lexically scoped (using "my"), declared beforehand using
1647 "our", or explicitly qualified to say which package the global variable
1650 =item glob failed (%s)
1652 (W glob) Something went wrong with the external program(s) used for
1653 C<glob> and C<< <*.c> >>. Usually, this means that you supplied a
1654 C<glob> pattern that caused the external program to fail and exit with a
1655 nonzero status. If the message indicates that the abnormal exit
1656 resulted in a coredump, this may also mean that your csh (C shell) is
1657 broken. If so, you should change all of the csh-related variables in
1658 config.sh: If you have tcsh, make the variables refer to it as if it
1659 were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them all
1660 empty (except that C<d_csh> should be C<'undef'>) so that Perl will
1661 think csh is missing. In either case, after editing config.sh, run
1662 C<./Configure -S> and rebuild Perl.
1664 =item Glob not terminated
1666 (F) The lexer saw a left angle bracket in a place where it was expecting
1667 a term, so it's looking for the corresponding right angle bracket, and
1668 not finding it. Chances are you left some needed parentheses out
1669 earlier in the line, and you really meant a "less than".
1671 =item Got an error from DosAllocMem
1673 (P) An error peculiar to OS/2. Most probably you're using an obsolete
1674 version of Perl, and this should not happen anyway.
1676 =item goto must have label
1678 (F) Unlike with "next" or "last", you're not allowed to goto an
1679 unspecified destination. See L<perlfunc/goto>.
1681 =item ()-group starts with a count
1683 (F) A ()-group started with a count. A count is
1684 supposed to follow something: a template character or a ()-group.
1685 See L<perlfunc/pack>.
1687 =item %s had compilation errors
1689 (F) The final summary message when a C<perl -c> fails.
1691 =item Had to create %s unexpectedly
1693 (S internal) A routine asked for a symbol from a symbol table that ought
1694 to have existed already, but for some reason it didn't, and had to be
1695 created on an emergency basis to prevent a core dump.
1697 =item Hash %%s missing the % in argument %d of %s()
1699 (D deprecated) Really old Perl let you omit the % on hash names in some
1700 spots. This is now heavily deprecated.
1702 =item %s has too many errors
1704 (F) The parser has given up trying to parse the program after 10 errors.
1705 Further error messages would likely be uninformative.
1707 =item Hexadecimal number > 0xffffffff non-portable
1709 (W portable) The hexadecimal number you specified is larger than 2**32-1
1710 (4294967295) and therefore non-portable between systems. See
1711 L<perlport> for more on portability concerns.
1713 =item Identifier too long
1715 (F) Perl limits identifiers (names for variables, functions, etc.) to
1716 about 250 characters for simple names, and somewhat more for compound
1717 names (like C<$A::B>). You've exceeded Perl's limits. Future versions
1718 of Perl are likely to eliminate these arbitrary limitations.
1720 =item Illegal binary digit %s
1722 (F) You used a digit other than 0 or 1 in a binary number.
1724 =item Illegal binary digit %s ignored
1726 (W digit) You may have tried to use a digit other than 0 or 1 in a
1727 binary number. Interpretation of the binary number stopped before the
1730 =item Illegal character %s (carriage return)
1732 (F) Perl normally treats carriage returns in the program text as it
1733 would any other whitespace, which means you should never see this error
1734 when Perl was built using standard options. For some reason, your
1735 version of Perl appears to have been built without this support. Talk
1736 to your Perl administrator.
1738 =item Illegal character in prototype for %s : %s
1740 (W syntax) An illegal character was found in a prototype declaration. Legal
1741 characters in prototypes are $, @, %, *, ;, [, ], &, and \.
1743 =item Illegal declaration of anonymous subroutine
1745 (F) When using the C<sub> keyword to construct an anonymous subroutine,
1746 you must always specify a block of code. See L<perlsub>.
1748 =item Illegal declaration of subroutine %s
1750 (F) A subroutine was not declared correctly. See L<perlsub>.
1752 =item Illegal division by zero
1754 (F) You tried to divide a number by 0. Either something was wrong in
1755 your logic, or you need to put a conditional in to guard against
1758 =item Illegal hexadecimal digit %s ignored
1760 (W digit) You may have tried to use a character other than 0 - 9 or
1761 A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal
1762 number stopped before the illegal character.
1764 =item Illegal modulus zero
1766 (F) You tried to divide a number by 0 to get the remainder. Most
1767 numbers don't take to this kindly.
1769 =item Illegal number of bits in vec
1771 (F) The number of bits in vec() (the third argument) must be a power of
1772 two from 1 to 32 (or 64, if your platform supports that).
1774 =item Illegal octal digit %s
1776 (F) You used an 8 or 9 in an octal number.
1778 =item Illegal octal digit %s ignored
1780 (W digit) You may have tried to use an 8 or 9 in an octal number.
1781 Interpretation of the octal number stopped before the 8 or 9.
1783 =item Illegal switch in PERL5OPT: %s
1785 (X) The PERL5OPT environment variable may only be used to set the
1786 following switches: B<-[DIMUdmtw]>.
1788 =item Ill-formed CRTL environ value "%s"
1790 (W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
1791 internal environ array, and encountered an element without the C<=>
1792 delimiter used to separate keys from values. The element is ignored.
1794 =item Ill-formed message in prime_env_iter: |%s|
1796 (W internal) A warning peculiar to VMS. Perl tried to read a logical
1797 name or CLI symbol definition when preparing to iterate over %ENV, and
1798 didn't see the expected delimiter between key and value, so the line was
1801 =item Impossible to activate assertion call
1803 (W assertions) You're calling an assertion function in a block that is
1804 not under the control of the C<assertions> pragma.
1806 =item (in cleanup) %s
1808 (W misc) This prefix usually indicates that a DESTROY() method raised
1809 the indicated exception. Since destructors are usually called by the
1810 system at arbitrary points during execution, and often a vast number of
1811 times, the warning is issued only once for any number of failures that
1812 would otherwise result in the same message being repeated.
1814 Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
1815 also result in this warning. See L<perlcall/G_KEEPERR>.
1817 =item In EBCDIC the v-string components cannot exceed 2147483647
1819 (F) An error peculiar to EBCDIC. Internally, v-strings are stored as
1820 Unicode code points, and encoded in EBCDIC as UTF-EBCDIC. The UTF-EBCDIC
1821 encoding is limited to code points no larger than 2147483647 (0x7FFFFFFF).
1823 =item Insecure dependency in %s
1825 (F) You tried to do something that the tainting mechanism didn't like.
1826 The tainting mechanism is turned on when you're running setuid or
1827 setgid, or when you specify B<-T> to turn it on explicitly. The
1828 tainting mechanism labels all data that's derived directly or indirectly
1829 from the user, who is considered to be unworthy of your trust. If any
1830 such data is used in a "dangerous" operation, you get this error. See
1831 L<perlsec> for more information.
1833 =item Insecure directory in %s
1835 (F) You can't use system(), exec(), or a piped open in a setuid or
1836 setgid script if C<$ENV{PATH}> contains a directory that is writable by
1837 the world. See L<perlsec>.
1839 =item Insecure $ENV{%s} while running %s
1841 (F) You can't use system(), exec(), or a piped open in a setuid or
1842 setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
1843 C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
1844 supplied (or potentially supplied) by the user. The script must set
1845 the path to a known value, using trustworthy data. See L<perlsec>.
1847 =item Integer overflow in %s number
1849 (W overflow) The hexadecimal, octal or binary number you have specified
1850 either as a literal or as an argument to hex() or oct() is too big for
1851 your architecture, and has been converted to a floating point number.
1852 On a 32-bit architecture the largest hexadecimal, octal or binary number
1853 representable without overflow is 0xFFFFFFFF, 037777777777, or
1854 0b11111111111111111111111111111111 respectively. Note that Perl
1855 transparently promotes all numbers to a floating point representation
1856 internally--subject to loss of precision errors in subsequent
1859 =item Integer overflow in version
1861 (F) Some portion of a version initialization is too large for the
1862 size of integers for your architecture. This is not a warning
1863 because there is no rational reason for a version to try and use a
1864 element larger than typically 2**32. This is usually caused by
1865 trying to use some odd mathematical operation as a version, like
1868 =item Internal disaster in regex; marked by <-- HERE in m/%s/
1870 (P) Something went badly wrong in the regular expression parser.
1871 The <-- HERE shows in the regular expression about where the problem was
1874 =item Internal inconsistency in tracking vforks
1876 (S) A warning peculiar to VMS. Perl keeps track of the number of times
1877 you've called C<fork> and C<exec>, to determine whether the current call
1878 to C<exec> should affect the current script or a subprocess (see
1879 L<perlvms/"exec LIST">). Somehow, this count has become scrambled, so
1880 Perl is making a guess and treating this C<exec> as a request to
1881 terminate the Perl script and execute the specified command.
1883 =item Internal urp in regex; marked by <-- HERE in m/%s/
1885 (P) Something went badly awry in the regular expression parser. The
1886 <-- HERE shows in the regular expression about where the problem was
1889 =item %s (...) interpreted as function
1891 (W syntax) You've run afoul of the rule that says that any list operator
1892 followed by parentheses turns into a function, with all the list
1893 operators arguments found inside the parentheses. See
1894 L<perlop/Terms and List Operators (Leftward)>.
1896 =item Invalid %s attribute: %s
1898 The indicated attribute for a subroutine or variable was not recognized
1899 by Perl or by a user-supplied handler. See L<attributes>.
1901 =item Invalid %s attributes: %s
1903 The indicated attributes for a subroutine or variable were not
1904 recognized by Perl or by a user-supplied handler. See L<attributes>.
1906 =item Invalid conversion in %s: "%s"
1908 (W printf) Perl does not understand the given format conversion. See
1909 L<perlfunc/sprintf>.
1911 =item Invalid [] range "%s" in regex; marked by <-- HERE in m/%s/
1913 (F) The range specified in a character class had a minimum character
1914 greater than the maximum character. One possibility is that you forgot the
1915 C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
1916 up to C<ff>. The <-- HERE shows in the regular expression about where the
1917 problem was discovered. See L<perlre>.
1919 =item Invalid range "%s" in transliteration operator
1921 (F) The range specified in the tr/// or y/// operator had a minimum
1922 character greater than the maximum character. See L<perlop>.
1924 =item Invalid separator character %s in attribute list
1926 (F) Something other than a colon or whitespace was seen between the
1927 elements of an attribute list. If the previous attribute had a
1928 parenthesised parameter list, perhaps that list was terminated too soon.
1931 =item Invalid separator character %s in PerlIO layer specification %s
1933 (W layer) When pushing layers onto the Perl I/O system, something other than a
1934 colon or whitespace was seen between the elements of a layer list.
1935 If the previous attribute had a parenthesised parameter list, perhaps that
1936 list was terminated too soon.
1938 =item Invalid type '%s' in %s
1940 (F) The given character is not a valid pack or unpack type.
1941 See L<perlfunc/pack>.
1942 (W) The given character is not a valid pack or unpack type but used to be
1945 =item Invalid version format (multiple underscores)
1947 (F) Versions may contain at most a single underscore, which signals
1948 that the version is a beta release. See L<version> for the allowed
1951 =item Invalid version format (underscores before decimal)
1953 (F) Versions may not contain decimals after the optional underscore.
1954 See L<version> for the allowed version formats.
1956 =item ioctl is not implemented
1958 (F) Your machine apparently doesn't implement ioctl(), which is pretty
1959 strange for a machine that supports C.
1961 =item ioctl() on unopened %s
1963 (W unopened) You tried ioctl() on a filehandle that was never opened.
1964 Check you control flow and number of arguments.
1966 =item IO layers (like "%s") unavailable
1968 (F) Your Perl has not been configured to have PerlIO, and therefore
1969 you cannot use IO layers. To have PerlIO Perl must be configured
1972 =item IO::Socket::atmark not implemented on this architecture
1974 (F) Your machine doesn't implement the sockatmark() functionality,
1975 neither as a system call or an ioctl call (SIOCATMARK).
1977 =item $* is no longer supported
1979 (D deprecated) The special variable C<$*>, deprecated in older perls, has
1980 been removed as of 5.9.0 and is no longer supported. You should use the
1981 C<//m> and C<//s> regexp modifiers instead.
1983 =item `%s' is not a code reference
1985 (W overload) The second (fourth, sixth, ...) argument of overload::constant
1986 needs to be a code reference. Either an anonymous subroutine, or a reference
1989 =item `%s' is not an overloadable type
1991 (W overload) You tried to overload a constant type the overload package is
1994 =item junk on end of regexp
1996 (P) The regular expression parser is confused.
1998 =item Label not found for "last %s"
2000 (F) You named a loop to break out of, but you're not currently in a loop
2001 of that name, not even if you count where you were called from. See
2004 =item Label not found for "next %s"
2006 (F) You named a loop to continue, but you're not currently in a loop of
2007 that name, not even if you count where you were called from. See
2010 =item Label not found for "redo %s"
2012 (F) You named a loop to restart, but you're not currently in a loop of
2013 that name, not even if you count where you were called from. See
2016 =item leaving effective %s failed
2018 (F) While under the C<use filetest> pragma, switching the real and
2019 effective uids or gids failed.
2021 =item length/code after end of string in unpack
2023 (F) While unpacking, the string buffer was alread used up when an unpack
2024 length/code combination tried to obtain more data. This results in
2025 an undefined value for the length. See L<perlfunc/pack>.
2027 =item listen() on closed socket %s
2029 (W closed) You tried to do a listen on a closed socket. Did you forget
2030 to check the return value of your socket() call? See
2033 =item Lookbehind longer than %d not implemented in regex; marked by <-- HERE in m/%s/
2035 (F) There is currently a limit on the length of string which lookbehind can
2036 handle. This restriction may be eased in a future release. The <-- HERE
2037 shows in the regular expression about where the problem was discovered.
2039 =item lstat() on filehandle %s
2041 (W io) You tried to do an lstat on a filehandle. What did you mean
2042 by that? lstat() makes sense only on filenames. (Perl did a fstat()
2043 instead on the filehandle.)
2045 =item Lvalue subs returning %s not implemented yet
2047 (F) Due to limitations in the current implementation, array and hash
2048 values cannot be returned in subroutines used in lvalue context. See
2049 L<perlsub/"Lvalue subroutines">.
2051 =item Malformed integer in [] in pack
2053 (F) Between the brackets enclosing a numeric repeat count only digits
2054 are permitted. See L<perlfunc/pack>.
2056 =item Malformed integer in [] in unpack
2058 (F) Between the brackets enclosing a numeric repeat count only digits
2059 are permitted. See L<perlfunc/pack>.
2061 =item Malformed PERLLIB_PREFIX
2063 (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
2070 with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
2071 a builtin library search path, prefix2 is substituted. The error may
2072 appear if components are not found, or are too long. See
2073 "PERLLIB_PREFIX" in L<perlos2>.
2075 =item Malformed prototype for %s: %s
2077 (F) You tried to use a function with a malformed prototype. The
2078 syntax of function prototypes is given a brief compile-time check for
2079 obvious errors like invalid characters. A more rigorous check is run
2080 when the function is called.
2082 =item Malformed UTF-8 character (%s)
2084 Perl detected something that didn't comply with UTF-8 encoding rules.
2086 One possible cause is that you read in data that you thought to be in
2087 UTF-8 but it wasn't (it was for example legacy 8-bit data). Another
2088 possibility is careless use of utf8::upgrade().
2090 =item Malformed UTF-16 surrogate
2092 Perl thought it was reading UTF-16 encoded character data but while
2093 doing it Perl met a malformed Unicode surrogate.
2095 =item %s matches null string many times in regex; marked by <-- HERE in m/%s/
2097 (W regexp) The pattern you've specified would be an infinite loop if the
2098 regular expression engine didn't specifically check for that. The <-- HERE
2099 shows in the regular expression about where the problem was discovered.
2102 =item "%s" may clash with future reserved word
2104 (W) This warning may be due to running a perl5 script through a perl4
2105 interpreter, especially if the word that is being warned about is
2108 =item % may not be used in pack
2110 (F) You can't pack a string by supplying a checksum, because the
2111 checksumming process loses information, and you can't go the other way.
2112 See L<perlfunc/unpack>.
2114 =item Method for operation %s not found in package %s during blessing
2116 (F) An attempt was made to specify an entry in an overloading table that
2117 doesn't resolve to a valid subroutine. See L<overload>.
2119 =item Method %s not permitted
2123 =item Might be a runaway multi-line %s string starting on line %d
2125 (S) An advisory indicating that the previous error may have been caused
2126 by a missing delimiter on a string or pattern, because it eventually
2127 ended earlier on the current line.
2129 =item Misplaced _ in number
2131 (W syntax) An underscore (underbar) in a numeric constant did not
2132 separate two digits.
2134 =item Missing %sbrace%s on \N{}
2136 (F) Wrong syntax of character name literal C<\N{charname}> within
2137 double-quotish context.
2139 =item Missing comma after first argument to %s function
2141 (F) While certain functions allow you to specify a filehandle or an
2142 "indirect object" before the argument list, this ain't one of them.
2144 =item Missing command in piped open
2146 (W pipe) You used the C<open(FH, "| command")> or
2147 C<open(FH, "command |")> construction, but the command was missing or
2150 =item Missing control char name in \c
2152 (F) A double-quoted string ended with "\c", without the required control
2155 =item Missing name in "my sub"
2157 (F) The reserved syntax for lexically scoped subroutines requires that
2158 they have a name with which they can be found.
2160 =item Missing $ on loop variable
2162 (F) Apparently you've been programming in B<csh> too much. Variables
2163 are always mentioned with the $ in Perl, unlike in the shells, where it
2164 can vary from one line to the next.
2166 =item (Missing operator before %s?)
2168 (S syntax) This is an educated guess made in conjunction with the message
2169 "%s found where operator expected". Often the missing operator is a comma.
2171 =item Missing right brace on %s
2173 (F) Missing right brace in C<\p{...}> or C<\P{...}>.
2175 =item Missing right curly or square bracket
2177 (F) The lexer counted more opening curly or square brackets than closing
2178 ones. As a general rule, you'll find it's missing near the place you
2181 =item (Missing semicolon on previous line?)
2183 (S syntax) This is an educated guess made in conjunction with the message
2184 "%s found where operator expected". Don't automatically put a semicolon on
2185 the previous line just because you saw this message.
2187 =item Modification of a read-only value attempted
2189 (F) You tried, directly or indirectly, to change the value of a
2190 constant. You didn't, of course, try "2 = 1", because the compiler
2191 catches that. But an easy way to do the same thing is:
2193 sub mod { $_[0] = 1 }
2196 Another way is to assign to a substr() that's off the end of the string.
2198 Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
2199 is aliased to a constant in the look I<LIST>:
2202 foreach my $n ($x, 2) {
2203 $n *= 2; # modifies the $x, but fails on attempt to modify the 2
2206 =item Modification of non-creatable array value attempted, %s
2208 (F) You tried to make an array value spring into existence, and the
2209 subscript was probably negative, even counting from end of the array
2212 =item Modification of non-creatable hash value attempted, %s
2214 (P) You tried to make a hash value spring into existence, and it
2215 couldn't be created for some peculiar reason.
2217 =item Module name must be constant
2219 (F) Only a bare module name is allowed as the first argument to a "use".
2221 =item Module name required with -%c option
2223 (F) The C<-M> or C<-m> options say that Perl should load some module, but
2224 you omitted the name of the module. Consult L<perlrun> for full details
2225 about C<-M> and C<-m>.
2227 =item More than one argument to open
2229 (F) The C<open> function has been asked to open multiple files. This
2230 can happen if you are trying to open a pipe to a command that takes a
2231 list of arguments, but have forgotten to specify a piped open mode.
2232 See L<perlfunc/open> for details.
2234 =item msg%s not implemented
2236 (F) You don't have System V message IPC on your system.
2238 =item Multidimensional syntax %s not supported
2240 (W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
2241 They're written like C<$foo[1][2][3]>, as in C.
2243 =item '/' must be followed by 'a*', 'A*' or 'Z*'
2245 (F) You had a pack template indicating a counted-length string,
2246 Currently the only things that can have their length counted are a*, A*
2247 or Z*. See L<perlfunc/pack>.
2249 =item '/' must follow a numeric type in unpack
2251 (F) You had an unpack template that contained a '/', but this did not
2252 follow some unpack specification producing a numeric value.
2253 See L<perlfunc/pack>.
2255 =item "my sub" not yet implemented
2257 (F) Lexically scoped subroutines are not yet implemented. Don't try
2260 =item "my" variable %s can't be in a package
2262 (F) Lexically scoped variables aren't in a package, so it doesn't make
2263 sense to try to declare one with a package qualifier on the front. Use
2264 local() if you want to localize a package variable.
2266 =item Name "%s::%s" used only once: possible typo
2268 (W once) Typographical errors often show up as unique variable names.
2269 If you had a good reason for having a unique name, then just mention it
2270 again somehow to suppress the message. The C<our> declaration is
2271 provided for this purpose.
2273 NOTE: This warning detects symbols that have been used only once so $c, @c,
2274 %c, *c, &c, sub c{}, c(), and c (the filehandle or format) are considered
2275 the same; if a program uses $c only once but also uses any of the others it
2276 will not trigger this warning.
2278 =item Negative '/' count in unpack
2280 (F) The length count obtained from a length/code unpack operation was
2281 negative. See L<perlfunc/pack>.
2283 =item Negative length
2285 (F) You tried to do a read/write/send/recv operation with a buffer
2286 length that is less than 0. This is difficult to imagine.
2288 =item Negative offset to vec in lvalue context
2290 (F) When C<vec> is called in an lvalue context, the second argument must be
2291 greater than or equal to zero.
2293 =item Nested quantifiers in regex; marked by <-- HERE in m/%s/
2295 (F) You can't quantify a quantifier without intervening parentheses. So
2296 things like ** or +* or ?* are illegal. The <-- HERE shows in the regular
2297 expression about where the problem was discovered.
2299 Note that the minimal matching quantifiers, C<*?>, C<+?>, and
2300 C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
2302 =item %s never introduced
2304 (S internal) The symbol in question was declared but somehow went out of
2305 scope before it could possibly have been used.
2307 =item Newline in left-justified string for %s
2309 (W printf) There is a newline in a string to be left justified by
2310 C<printf> or C<sprintf>.
2312 The padding spaces will appear after the newline, which is probably not
2313 what you wanted. Usually you should remove the newline from the string
2314 and put formatting characters in the C<sprintf> format.
2316 =item No %s allowed while running setuid
2318 (F) Certain operations are deemed to be too insecure for a setuid or
2319 setgid script to even be allowed to attempt. Generally speaking there
2320 will be another way to do what you want that is, if not secure, at least
2321 securable. See L<perlsec>.
2323 =item No comma allowed after %s
2325 (F) A list operator that has a filehandle or "indirect object" is not
2326 allowed to have a comma between that and the following arguments.
2327 Otherwise it'd be just another one of the arguments.
2329 One possible cause for this is that you expected to have imported a
2330 constant to your name space with B<use> or B<import> while no such
2331 importing took place, it may for example be that your operating system
2332 does not support that particular constant. Hopefully you did use an
2333 explicit import list for the constants you expect to see, please see
2334 L<perlfunc/use> and L<perlfunc/import>. While an explicit import list
2335 would probably have caught this error earlier it naturally does not
2336 remedy the fact that your operating system still does not support that
2337 constant. Maybe you have a typo in the constants of the symbol import
2338 list of B<use> or B<import> or in the constant name at the line where
2339 this error was triggered?
2341 =item No command into which to pipe on command line
2343 (F) An error peculiar to VMS. Perl handles its own command line
2344 redirection, and found a '|' at the end of the command line, so it
2345 doesn't know where you want to pipe the output from this command.
2347 =item No DB::DB routine defined
2349 (F) The currently executing code was compiled with the B<-d> switch, but
2350 for some reason the perl5db.pl file (or some facsimile thereof) didn't
2351 define a routine to be called at the beginning of each statement. Which
2352 is odd, because the file should have been required automatically, and
2353 should have blown up the require if it didn't parse right.
2355 =item No dbm on this machine
2357 (P) This is counted as an internal error, because every machine should
2358 supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>.
2360 =item No DBsub routine
2362 (F) The currently executing code was compiled with the B<-d> switch,
2363 but for some reason the perl5db.pl file (or some facsimile thereof)
2364 didn't define a DB::sub routine to be called at the beginning of each
2365 ordinary subroutine call.
2367 =item No B<-e> allowed in setuid scripts
2369 (F) A setuid script can't be specified by the user.
2371 =item No error file after 2> or 2>> on command line
2373 (F) An error peculiar to VMS. Perl handles its own command line
2374 redirection, and found a '2>' or a '2>>' on the command line, but can't
2375 find the name of the file to which to write data destined for stderr.
2377 =item No group ending character '%c' found in template
2379 (F) A pack or unpack template has an opening '(' or '[' without its
2380 matching counterpart. See L<perlfunc/pack>.
2382 =item No input file after < on command line
2384 (F) An error peculiar to VMS. Perl handles its own command line
2385 redirection, and found a '<' on the command line, but can't find the
2386 name of the file from which to read data for stdin.
2390 (F) The setuid emulator requires that scripts have a well-formed #! line
2391 even on machines that don't support the #! construct.
2393 =item "no" not allowed in expression
2395 (F) The "no" keyword is recognized and executed at compile time, and
2396 returns no useful value. See L<perlmod>.
2398 =item No output file after > on command line
2400 (F) An error peculiar to VMS. Perl handles its own command line
2401 redirection, and found a lone '>' at the end of the command line, so it
2402 doesn't know where you wanted to redirect stdout.
2404 =item No output file after > or >> on command line
2406 (F) An error peculiar to VMS. Perl handles its own command line
2407 redirection, and found a '>' or a '>>' on the command line, but can't
2408 find the name of the file to which to write data destined for stdout.
2410 =item No package name allowed for variable %s in "our"
2412 (F) Fully qualified variable names are not allowed in "our"
2413 declarations, because that doesn't make much sense under existing
2414 semantics. Such syntax is reserved for future extensions.
2416 =item No Perl script found in input
2418 (F) You called C<perl -x>, but no line was found in the file beginning
2419 with #! and containing the word "perl".
2421 =item No setregid available
2423 (F) Configure didn't find anything resembling the setregid() call for
2426 =item No setreuid available
2428 (F) Configure didn't find anything resembling the setreuid() call for
2431 =item No space allowed after -%c
2433 (F) The argument to the indicated command line switch must follow
2434 immediately after the switch, without intervening spaces.
2436 =item No %s specified for -%c
2438 (F) The indicated command line switch needs a mandatory argument, but
2439 you haven't specified one.
2441 =item No such class %s
2443 (F) You provided a class qualifier in a "my" or "our" declaration, but
2444 this class doesn't exist at this point in your program.
2446 =item No such pipe open
2448 (P) An error peculiar to VMS. The internal routine my_pclose() tried to
2449 close a pipe which hadn't been opened. This should have been caught
2450 earlier as an attempt to close an unopened filehandle.
2452 =item No such signal: SIG%s
2454 (W signal) You specified a signal name as a subscript to %SIG that was
2455 not recognized. Say C<kill -l> in your shell to see the valid signal
2456 names on your system.
2458 =item Not a CODE reference
2460 (F) Perl was trying to evaluate a reference to a code value (that is, a
2461 subroutine), but found a reference to something else instead. You can
2462 use the ref() function to find out what kind of ref it really was. See
2465 =item Not a format reference
2467 (F) I'm not sure how you managed to generate a reference to an anonymous
2468 format, but this indicates you did, and that it didn't exist.
2470 =item Not a GLOB reference
2472 (F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
2473 symbol table entry that looks like C<*foo>), but found a reference to
2474 something else instead. You can use the ref() function to find out what
2475 kind of ref it really was. See L<perlref>.
2477 =item Not a HASH reference
2479 (F) Perl was trying to evaluate a reference to a hash value, but found a
2480 reference to something else instead. You can use the ref() function to
2481 find out what kind of ref it really was. See L<perlref>.
2483 =item Not an ARRAY reference
2485 (F) Perl was trying to evaluate a reference to an array value, but found
2486 a reference to something else instead. You can use the ref() function
2487 to find out what kind of ref it really was. See L<perlref>.
2489 =item Not a perl script
2491 (F) The setuid emulator requires that scripts have a well-formed #! line
2492 even on machines that don't support the #! construct. The line must
2495 =item Not a SCALAR reference
2497 (F) Perl was trying to evaluate a reference to a scalar value, but found
2498 a reference to something else instead. You can use the ref() function
2499 to find out what kind of ref it really was. See L<perlref>.
2501 =item Not a subroutine reference
2503 (F) Perl was trying to evaluate a reference to a code value (that is, a
2504 subroutine), but found a reference to something else instead. You can
2505 use the ref() function to find out what kind of ref it really was. See
2508 =item Not a subroutine reference in overload table
2510 (F) An attempt was made to specify an entry in an overloading table that
2511 doesn't somehow point to a valid subroutine. See L<overload>.
2513 =item Not enough arguments for %s
2515 (F) The function requires more arguments than you specified.
2517 =item Not enough format arguments
2519 (W syntax) A format specified more picture fields than the next line
2520 supplied. See L<perlform>.
2524 (A) You've accidentally run your script through the Bourne shell instead
2525 of Perl. Check the #! line, or manually feed your script into Perl
2528 =item no UTC offset information; assuming local time is UTC
2530 (S) A warning peculiar to VMS. Perl was unable to find the local
2531 timezone offset, so it's assuming that local system time is equivalent
2532 to UTC. If it's not, define the logical name
2533 F<SYS$TIMEZONE_DIFFERENTIAL> to translate to the number of seconds which
2534 need to be added to UTC to get local time.
2536 =item Null filename used
2538 (F) You can't require the null filename, especially because on many
2539 machines that means the current directory! See L<perlfunc/require>.
2541 =item NULL OP IN RUN
2543 (P debugging) Some internal routine called run() with a null opcode
2546 =item Null picture in formline
2548 (F) The first argument to formline must be a valid format picture
2549 specification. It was found to be empty, which probably means you
2550 supplied it an uninitialized value. See L<perlform>.
2554 (P) An attempt was made to realloc NULL.
2556 =item NULL regexp argument
2558 (P) The internal pattern matching routines blew it big time.
2560 =item NULL regexp parameter
2562 (P) The internal pattern matching routines are out of their gourd.
2564 =item Number too long
2566 (F) Perl limits the representation of decimal numbers in programs to
2567 about 250 characters. You've exceeded that length. Future
2568 versions of Perl are likely to eliminate this arbitrary limitation. In
2569 the meantime, try using scientific notation (e.g. "1e6" instead of
2572 =item Octal number in vector unsupported
2574 (F) Numbers with a leading C<0> are not currently allowed in vectors.
2575 The octal number interpretation of such numbers may be supported in a
2578 =item Octal number > 037777777777 non-portable
2580 (W portable) The octal number you specified is larger than 2**32-1
2581 (4294967295) and therefore non-portable between systems. See
2582 L<perlport> for more on portability concerns.
2584 See also L<perlport> for writing portable code.
2586 =item Odd number of arguments for overload::constant
2588 (W overload) The call to overload::constant contained an odd number of
2589 arguments. The arguments should come in pairs.
2591 =item Odd number of elements in anonymous hash
2593 (W misc) You specified an odd number of elements to initialize a hash,
2594 which is odd, because hashes come in key/value pairs.
2596 =item Odd number of elements in hash assignment
2598 (W misc) You specified an odd number of elements to initialize a hash,
2599 which is odd, because hashes come in key/value pairs.
2601 =item Offset outside string
2603 (F) You tried to do a read/write/send/recv operation with an offset
2604 pointing outside the buffer. This is difficult to imagine. The sole
2605 exception to this is that C<sysread()>ing past the buffer will extend
2606 the buffer and zero pad the new area.
2608 =item %s() on unopened %s
2610 (W unopened) An I/O operation was attempted on a filehandle that was
2611 never initialized. You need to do an open(), a sysopen(), or a socket()
2612 call, or call a constructor from the FileHandle package.
2614 =item -%s on unopened filehandle %s
2616 (W unopened) You tried to invoke a file test operator on a filehandle
2617 that isn't open. Check your control flow. See also L<perlfunc/-X>.
2621 (S internal) An internal warning that the grammar is screwed up.
2625 (S internal) An internal warning that the grammar is screwed up.
2627 =item Operation `%s': no method found, %s
2629 (F) An attempt was made to perform an overloaded operation for which no
2630 handler was defined. While some handlers can be autogenerated in terms
2631 of other handlers, there is no default handler for any operation, unless
2632 C<fallback> overloading key is specified to be true. See L<overload>.
2634 =item Operator or semicolon missing before %s
2636 (S ambiguous) You used a variable or subroutine call where the parser
2637 was expecting an operator. The parser has assumed you really meant to
2638 use an operator, but this is highly likely to be incorrect. For
2639 example, if you say "*foo *foo" it will be interpreted as if you said
2642 =item "our" variable %s redeclared
2644 (W misc) You seem to have already declared the same global once before
2645 in the current lexical scope.
2647 =item Out of memory!
2649 (X) The malloc() function returned 0, indicating there was insufficient
2650 remaining memory (or virtual memory) to satisfy the request. Perl has
2651 no option but to exit immediately.
2653 At least in Unix you may be able to get past this by increasing your
2654 process datasize limits: in csh/tcsh use C<limit> and
2655 C<limit datasize n> (where C<n> is the number of kilobytes) to check
2656 the current limits and change them, and in ksh/bash/zsh use C<ulimit -a>
2657 and C<ulimit -d n>, respectively.
2659 =item Out of memory during "large" request for %s
2661 (F) The malloc() function returned 0, indicating there was insufficient
2662 remaining memory (or virtual memory) to satisfy the request. However,
2663 the request was judged large enough (compile-time default is 64K), so a
2664 possibility to shut down by trapping this error is granted.
2666 =item Out of memory during %s extend
2668 (X) An attempt was made to extend an array, a list, or a string beyond
2669 the largest possible memory allocation.
2671 =item Out of memory during request for %s
2673 (X|F) The malloc() function returned 0, indicating there was
2674 insufficient remaining memory (or virtual memory) to satisfy the
2677 The request was judged to be small, so the possibility to trap it
2678 depends on the way perl was compiled. By default it is not trappable.
2679 However, if compiled for this, Perl may use the contents of C<$^M> as an
2680 emergency pool after die()ing with this message. In this case the error
2681 is trappable I<once>, and the error message will include the line and file
2682 where the failed request happened.
2684 =item Out of memory during ridiculously large request
2686 (F) You can't allocate more than 2^31+"small amount" bytes. This error
2687 is most likely to be caused by a typo in the Perl program. e.g.,
2688 C<$arr[time]> instead of C<$arr[$time]>.
2690 =item Out of memory for yacc stack
2692 (F) The yacc parser wanted to grow its stack so it could continue
2693 parsing, but realloc() wouldn't give it more memory, virtual or
2696 =item '@' outside of string in unpack
2698 (F) You had a template that specified an absolute position outside
2699 the string being unpacked. See L<perlfunc/pack>.
2701 =item %s package attribute may clash with future reserved word: %s
2703 (W reserved) A lowercase attribute name was used that had a
2704 package-specific handler. That name might have a meaning to Perl itself
2705 some day, even though it doesn't yet. Perhaps you should use a
2706 mixed-case attribute name, instead. See L<attributes>.
2708 =item pack/unpack repeat count overflow
2710 (F) You can't specify a repeat count so large that it overflows your
2711 signed integers. See L<perlfunc/pack>.
2715 (W io) A single call to write() produced more lines than can fit on a
2716 page. See L<perlform>.
2720 (P) An internal error.
2722 =item panic: ck_grep
2724 (P) Failed an internal consistency check trying to compile a grep.
2726 =item panic: ck_split
2728 (P) Failed an internal consistency check trying to compile a split.
2730 =item panic: corrupt saved stack index
2732 (P) The savestack was requested to restore more localized values than
2733 there are in the savestack.
2735 =item panic: del_backref
2737 (P) Failed an internal consistency check while trying to reset a weak
2740 =item panic: Devel::DProf inconsistent subroutine return
2742 (P) Devel::DProf called a subroutine that exited using goto(LABEL),
2743 last(LABEL) or next(LABEL). Leaving that way a subroutine called from
2744 an XSUB will lead very probably to a crash of the interpreter. This is
2745 a bug that will hopefully one day get fixed.
2749 (P) We popped the context stack to an eval context, and then discovered
2750 it wasn't an eval context.
2752 =item panic: do_subst
2754 (P) The internal pp_subst() routine was called with invalid operational
2757 =item panic: do_trans_%s
2759 (P) The internal do_trans routines were called with invalid operational
2764 (P) The library function frexp() failed, making printf("%f") impossible.
2768 (P) We popped the context stack to a context with the specified label,
2769 and then discovered it wasn't a context we know how to do a goto in.
2771 =item panic: INTERPCASEMOD
2773 (P) The lexer got into a bad state at a case modifier.
2775 =item panic: INTERPCONCAT
2777 (P) The lexer got into a bad state parsing a string with brackets.
2779 =item panic: kid popen errno read
2781 (F) forked child returned an incomprehensible message about its errno.
2785 (P) We popped the context stack to a block context, and then discovered
2786 it wasn't a block context.
2788 =item panic: leave_scope clearsv
2790 (P) A writable lexical variable became read-only somehow within the
2793 =item panic: leave_scope inconsistency
2795 (P) The savestack probably got out of sync. At least, there was an
2796 invalid enum on the top of it.
2798 =item panic: magic_killbackrefs
2800 (P) Failed an internal consistency check while trying to reset all weak
2801 references to an object.
2805 (P) Something requested a negative number of bytes of malloc.
2807 =item panic: mapstart
2809 (P) The compiler is screwed up with respect to the map() function.
2811 =item panic: memory wrap
2813 (P) Something tried to allocate more memory than possible.
2815 =item panic: null array
2817 (P) One of the internal array routines was passed a null AV pointer.
2819 =item panic: pad_alloc
2821 (P) The compiler got confused about which scratch pad it was allocating
2822 and freeing temporaries and lexicals from.
2824 =item panic: pad_free curpad
2826 (P) The compiler got confused about which scratch pad it was allocating
2827 and freeing temporaries and lexicals from.
2829 =item panic: pad_free po
2831 (P) An invalid scratch pad offset was detected internally.
2833 =item panic: pad_reset curpad
2835 (P) The compiler got confused about which scratch pad it was allocating
2836 and freeing temporaries and lexicals from.
2838 =item panic: pad_sv po
2840 (P) An invalid scratch pad offset was detected internally.
2842 =item panic: pad_swipe curpad
2844 (P) The compiler got confused about which scratch pad it was allocating
2845 and freeing temporaries and lexicals from.
2847 =item panic: pad_swipe po
2849 (P) An invalid scratch pad offset was detected internally.
2851 =item panic: pp_iter
2853 (P) The foreach iterator got called in a non-loop context frame.
2855 =item panic: pp_match%s
2857 (P) The internal pp_match() routine was called with invalid operational
2860 =item panic: pp_split
2862 (P) Something terrible went wrong in setting up for the split.
2864 =item panic: realloc
2866 (P) Something requested a negative number of bytes of realloc.
2868 =item panic: restartop
2870 (P) Some internal routine requested a goto (or something like it), and
2871 didn't supply the destination.
2875 (P) We popped the context stack to a subroutine or eval context, and
2876 then discovered it wasn't a subroutine or eval context.
2878 =item panic: scan_num
2880 (P) scan_num() got called on something that wasn't a number.
2882 =item panic: sv_insert
2884 (P) The sv_insert() routine was told to remove more string than there
2887 =item panic: top_env
2889 (P) The compiler attempted to do a goto, or something weird like that.
2891 =item panic: utf16_to_utf8: odd bytelen
2893 (P) Something tried to call utf16_to_utf8 with an odd (as opposed
2894 to even) byte length.
2898 (P) The lexer got into a bad state while processing a case modifier.
2900 =item Parentheses missing around "%s" list
2902 (W parenthesis) You said something like
2908 my ($foo, $bar) = @_;
2910 Remember that "my", "our", and "local" bind tighter than comma.
2912 =item C<-p> destination: %s
2914 (F) An error occurred during the implicit output invoked by the C<-p>
2915 command-line switch. (This output goes to STDOUT unless you've
2916 redirected it with select().)
2918 =item (perhaps you forgot to load "%s"?)
2920 (F) This is an educated guess made in conjunction with the message
2921 "Can't locate object method \"%s\" via package \"%s\"". It often means
2922 that a method requires a package that has not been loaded.
2924 =item Perl %s required--this is only version %s, stopped
2926 (F) The module in question uses features of a version of Perl more
2927 recent than the currently running version. How long has it been since
2928 you upgraded, anyway? See L<perlfunc/require>.
2930 =item Perl_my_%s() not available
2932 (F) Your platform has very uncommon byte-order and integer size,
2933 so it was not possible to set up some or all fixed-width byte-order
2934 conversion functions. This is only a problem when you're using the
2935 '<' or '>' modifiers in (un)pack templates. See L<perlfunc/pack>.
2937 =item PERL_SH_DIR too long
2939 (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
2940 C<sh>-shell in. See "PERL_SH_DIR" in L<perlos2>.
2942 =item PERL_SIGNALS illegal: "%s"
2944 See L<perlrun/PERL_SIGNALS> for legal values.
2946 =item perl: warning: Setting locale failed.
2948 (S) The whole warning message will look something like:
2950 perl: warning: Setting locale failed.
2951 perl: warning: Please check that your locale settings:
2954 are supported and installed on your system.
2955 perl: warning: Falling back to the standard locale ("C").
2957 Exactly what were the failed locale settings varies. In the above the
2958 settings were that the LC_ALL was "En_US" and the LANG had no value.
2959 This error means that Perl detected that you and/or your operating
2960 system supplier and/or system administrator have set up the so-called
2961 locale system but Perl could not use those settings. This was not
2962 dead serious, fortunately: there is a "default locale" called "C" that
2963 Perl can and will use, the script will be run. Before you really fix
2964 the problem, however, you will get the same error message each time
2965 you run Perl. How to really fix the problem can be found in
2966 L<perllocale> section B<LOCALE PROBLEMS>.
2968 =item Permission denied
2970 (F) The setuid emulator in suidperl decided you were up to no good.
2972 =item pid %x not a child
2974 (W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a
2975 process which isn't a subprocess of the current process. While this is
2976 fine from VMS' perspective, it's probably not what you intended.
2978 =item 'P' must have an explicit size in unpack
2980 (F) The unpack format P must have an explicit size, not "*".
2982 =item B<-P> not allowed for setuid/setgid script
2984 (F) The script would have to be opened by the C preprocessor by name,
2985 which provides a race condition that breaks security.
2987 =item POSIX class [:%s:] unknown in regex; marked by <-- HERE in m/%s/
2989 (F) The class in the character class [: :] syntax is unknown. The <-- HERE
2990 shows in the regular expression about where the problem was discovered.
2991 Note that the POSIX character classes do B<not> have the C<is> prefix
2992 the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
2993 not C<isprint>. See L<perlre>.
2995 =item POSIX getpgrp can't take an argument
2997 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
2998 the BSD version, which takes a pid.
3000 =item POSIX syntax [%s] belongs inside character classes in regex; marked by <-- HERE in m/%s/
3002 (W regexp) The character class constructs [: :], [= =], and [. .] go
3003 I<inside> character classes, the [] are part of the construct, for example:
3004 /[012[:alpha:]345]/. Note that [= =] and [. .] are not currently
3005 implemented; they are simply placeholders for future extensions and will
3006 cause fatal errors. The <-- HERE shows in the regular expression about
3007 where the problem was discovered. See L<perlre>.
3009 =item POSIX syntax [. .] is reserved for future extensions in regex; marked by <-- HERE in m/%s/
3011 (F regexp) Within regular expression character classes ([]) the syntax
3012 beginning with "[." and ending with ".]" is reserved for future extensions.
3013 If you need to represent those character sequences inside a regular
3014 expression character class, just quote the square brackets with the
3015 backslash: "\[." and ".\]". The <-- HERE shows in the regular expression
3016 about where the problem was discovered. See L<perlre>.
3018 =item POSIX syntax [= =] is reserved for future extensions in regex; marked by <-- HERE in m/%s/
3020 (F) Within regular expression character classes ([]) the syntax beginning
3021 with "[=" and ending with "=]" is reserved for future extensions. If you
3022 need to represent those character sequences inside a regular expression
3023 character class, just quote the square brackets with the backslash: "\[="
3024 and "=\]". The <-- HERE shows in the regular expression about where the
3025 problem was discovered. See L<perlre>.
3027 =item Possible attempt to put comments in qw() list
3029 (W qw) qw() lists contain items separated by whitespace; as with literal
3030 strings, comment characters are not ignored, but are instead treated as
3031 literal data. (You may have used different delimiters than the
3032 parentheses shown here; braces are also frequently used.)
3034 You probably wrote something like this:
3041 when you should have written this:
3048 If you really want comments, build your list the
3049 old-fashioned way, with quotes and commas:
3053 'b', # another comment
3056 =item Possible attempt to separate words with commas
3058 (W qw) qw() lists contain items separated by whitespace; therefore
3059 commas aren't needed to separate the items. (You may have used
3060 different delimiters than the parentheses shown here; braces are also
3063 You probably wrote something like this:
3067 which puts literal commas into some of the list items. Write it without
3068 commas if you don't want them to appear in your data:
3072 =item Possible memory corruption: %s overflowed 3rd argument
3074 (F) An ioctl() or fcntl() returned more than Perl was bargaining for.
3075 Perl guesses a reasonable buffer size, but puts a sentinel byte at the
3076 end of the buffer just in case. This sentinel byte got clobbered, and
3077 Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
3079 =item Possible precedence problem on bitwise %c operator
3081 (W precedence) Your program uses a bitwise logical operator in conjunction
3082 with a numeric comparison operator, like this :
3084 if ($x & $y == 0) { ... }
3086 This expression is actually equivalent to C<$x & ($y == 0)>, due to the
3087 higher precedence of C<==>. This is probably not what you want. (If you
3088 really meant to write this, disable the warning, or, better, put the
3089 parentheses explicitly and write C<$x & ($y == 0)>).
3091 =item Possible unintended interpolation of %s in string
3093 (W ambiguous) You said something like `@foo' in a double-quoted string
3094 but there was no array C<@foo> in scope at the time. If you wanted a
3095 literal @foo, then write it as \@foo; otherwise find out what happened
3096 to the array you apparently lost track of.
3098 =item Possible Y2K bug: %s
3100 (W y2k) You are concatenating the number 19 with another number, which
3101 could be a potential Year 2000 problem.
3103 =item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
3105 (D deprecated) You have written something like this:
3109 use attrs qw(locked);
3112 You should use the new declaration syntax instead.
3118 The C<use attrs> pragma is now obsolete, and is only provided for
3119 backward-compatibility. See L<perlsub/"Subroutine Attributes">.
3121 =item Precedence problem: open %s should be open(%s)
3123 (S precedence) The old irregular construct
3127 is now misinterpreted as
3131 because of the strict regularization of Perl 5's grammar into unary and
3132 list operators. (The old open was a little of both.) You must put
3133 parentheses around the filehandle, or use the new "or" operator instead
3136 =item Premature end of script headers
3140 =item printf() on closed filehandle %s
3142 (W closed) The filehandle you're writing to got itself closed sometime
3143 before now. Check your control flow.
3145 =item print() on closed filehandle %s
3147 (W closed) The filehandle you're printing on got itself closed sometime
3148 before now. Check your control flow.
3150 =item Process terminated by SIG%s
3152 (W) This is a standard message issued by OS/2 applications, while *nix
3153 applications die in silence. It is considered a feature of the OS/2
3154 port. One can easily disable this by appropriate sighandlers, see
3155 L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT"
3158 =item Prototype mismatch: %s vs %s
3160 (S prototype) The subroutine being declared or defined had previously been
3161 declared or defined with a different function prototype.
3163 =item Prototype not terminated
3165 (F) You've omitted the closing parenthesis in a function prototype
3168 =item Quantifier follows nothing in regex; marked by <-- HERE in m/%s/
3170 (F) You started a regular expression with a quantifier. Backslash it if you
3171 meant it literally. The <-- HERE shows in the regular expression about
3172 where the problem was discovered. See L<perlre>.
3174 =item Quantifier in {,} bigger than %d in regex; marked by <-- HERE in m/%s/
3176 (F) There is currently a limit to the size of the min and max values of the
3177 {min,max} construct. The <-- HERE shows in the regular expression about where
3178 the problem was discovered. See L<perlre>.
3180 =item Quantifier unexpected on zero-length expression; marked by <-- HERE in m/%s/
3182 (W regexp) You applied a regular expression quantifier in a place where
3183 it makes no sense, such as on a zero-width assertion. Try putting the
3184 quantifier inside the assertion instead. For example, the way to match
3185 "abc" provided that it is followed by three repetitions of "xyz" is
3186 C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
3188 The <-- HERE shows in the regular expression about where the problem was
3191 =item Range iterator outside integer range
3193 (F) One (or both) of the numeric arguments to the range operator ".."
3194 are outside the range which can be represented by integers internally.
3195 One possible workaround is to force Perl to use magical string increment
3196 by prepending "0" to your numbers.
3198 =item readline() on closed filehandle %s
3200 (W closed) The filehandle you're reading from got itself closed sometime
3201 before now. Check your control flow.
3203 =item read() on closed filehandle %s
3205 (W closed) You tried to read from a closed filehandle.
3207 =item read() on unopened filehandle %s
3209 (W unopened) You tried to read from a filehandle that was never opened.
3211 =item Reallocation too large: %lx
3213 (F) You can't allocate more than 64K on an MS-DOS machine.
3215 =item realloc() of freed memory ignored
3217 (S malloc) An internal routine called realloc() on something that had
3220 =item Recompile perl with B<-D>DEBUGGING to use B<-D> switch
3222 (F debugging) You can't use the B<-D> option unless the code to produce
3223 the desired output is compiled into Perl, which entails some overhead,
3224 which is why it's currently left out of your copy.
3226 =item Recursive inheritance detected in package '%s'
3228 (F) More than 100 levels of inheritance were used. Probably indicates
3229 an unintended loop in your inheritance hierarchy.
3231 =item Recursive inheritance detected while looking for method %s
3233 (F) More than 100 levels of inheritance were encountered while invoking
3234 a method. Probably indicates an unintended loop in your inheritance
3237 =item Reference found where even-sized list expected
3239 (W misc) You gave a single reference where Perl was expecting a list
3240 with an even number of elements (for assignment to a hash). This usually
3241 means that you used the anon hash constructor when you meant to use
3242 parens. In any case, a hash requires key/value B<pairs>.
3244 %hash = { one => 1, two => 2, }; # WRONG
3245 %hash = [ qw/ an anon array / ]; # WRONG
3246 %hash = ( one => 1, two => 2, ); # right
3247 %hash = qw( one 1 two 2 ); # also fine
3249 =item Reference is already weak
3251 (W misc) You have attempted to weaken a reference that is already weak.
3252 Doing so has no effect.
3254 =item Reference miscount in sv_replace()
3256 (W internal) The internal sv_replace() function was handed a new SV with
3257 a reference count of other than 1.
3259 =item Reference to nonexistent group in regex; marked by <-- HERE in m/%s/
3261 (F) You used something like C<\7> in your regular expression, but there are
3262 not at least seven sets of capturing parentheses in the expression. If you
3263 wanted to have the character with value 7 inserted into the regular expression,
3264 prepend a zero to make the number at least two digits: C<\07>
3266 The <-- HERE shows in the regular expression about where the problem was
3269 =item regexp memory corruption
3271 (P) The regular expression engine got confused by what the regular
3272 expression compiler gave it.
3274 =item Regexp out of space
3276 (P) A "can't happen" error, because safemalloc() should have caught it
3279 =item Repeated format line will never terminate (~~ and @# incompatible)
3281 (F) Your format containes the ~~ repeat-until-blank sequence and a
3282 numeric field that will never go blank so that the repetition never
3283 terminates. You might use ^# instead. See L<perlform>.
3285 =item Reversed %s= operator
3287 (W syntax) You wrote your assignment operator backwards. The = must
3288 always comes last, to avoid ambiguity with subsequent unary operators.
3290 =item Runaway format
3292 (F) Your format contained the ~~ repeat-until-blank sequence, but it
3293 produced 200 lines at once, and the 200th line looked exactly like the
3294 199th line. Apparently you didn't arrange for the arguments to exhaust
3295 themselves, either by using ^ instead of @ (for scalar variables), or by
3296 shifting or popping (for array variables). See L<perlform>.
3298 =item Scalars leaked: %d
3300 (P) Something went wrong in Perl's internal bookkeeping of scalars:
3301 not all scalar variables were deallocated by the time Perl exited.
3302 What this usually indicates is a memory leak, which is of course bad,
3303 especially if the Perl program is intended to be long-running.
3305 =item Scalar value @%s[%s] better written as $%s[%s]
3307 (W syntax) You've used an array slice (indicated by @) to select a
3308 single element of an array. Generally it's better to ask for a scalar
3309 value (indicated by $). The difference is that C<$foo[&bar]> always
3310 behaves like a scalar, both when assigning to it and when evaluating its
3311 argument, while C<@foo[&bar]> behaves like a list when you assign to it,
3312 and provides a list context to its subscript, which can do weird things
3313 if you're expecting only one subscript.
3315 On the other hand, if you were actually hoping to treat the array
3316 element as a list, you need to look into how references work, because
3317 Perl will not magically convert between scalars and lists for you. See
3320 =item Scalar value @%s{%s} better written as $%s{%s}
3322 (W syntax) You've used a hash slice (indicated by @) to select a single
3323 element of a hash. Generally it's better to ask for a scalar value
3324 (indicated by $). The difference is that C<$foo{&bar}> always behaves
3325 like a scalar, both when assigning to it and when evaluating its
3326 argument, while C<@foo{&bar}> behaves like a list when you assign to it,
3327 and provides a list context to its subscript, which can do weird things
3328 if you're expecting only one subscript.
3330 On the other hand, if you were actually hoping to treat the hash element
3331 as a list, you need to look into how references work, because Perl will
3332 not magically convert between scalars and lists for you. See
3335 =item Script is not setuid/setgid in suidperl
3337 (F) Oddly, the suidperl program was invoked on a script without a setuid
3338 or setgid bit set. This doesn't make much sense.
3340 =item Search pattern not terminated
3342 (F) The lexer couldn't find the final delimiter of a // or m{}
3343 construct. Remember that bracketing delimiters count nesting level.
3344 Missing the leading C<$> from a variable C<$m> may cause this error.
3346 Note that since Perl 5.9.0 a // can also be the I<defined-or>
3347 construct, not just the empty search pattern. Therefore code written
3348 in Perl 5.9.0 or later that uses the // as the I<defined-or> can be
3349 misparsed by pre-5.9.0 Perls as a non-terminated search pattern.
3351 =item %sseek() on unopened filehandle
3353 (W unopened) You tried to use the seek() or sysseek() function on a
3354 filehandle that was either never opened or has since been closed.
3356 =item select not implemented
3358 (F) This machine doesn't implement the select() system call.
3360 =item Self-ties of arrays and hashes are not supported
3362 (F) Self-ties are of arrays and hashes are not supported in
3363 the current implementation.
3365 =item Semicolon seems to be missing
3367 (W semicolon) A nearby syntax error was probably caused by a missing
3368 semicolon, or possibly some other missing operator, such as a comma.
3370 =item semi-panic: attempt to dup freed string
3372 (S internal) The internal newSVsv() routine was called to duplicate a
3373 scalar that had previously been marked as free.
3375 =item sem%s not implemented
3377 (F) You don't have System V semaphore IPC on your system.
3379 =item send() on closed socket %s
3381 (W closed) The socket you're sending to got itself closed sometime
3382 before now. Check your control flow.
3384 =item Sequence (? incomplete in regex; marked by <-- HERE in m/%s/
3386 (F) A regular expression ended with an incomplete extension (?. The <-- HERE
3387 shows in the regular expression about where the problem was discovered. See
3390 =item Sequence (?%s...) not implemented in regex; marked by <-- HERE in m/%s/
3392 (F) A proposed regular expression extension has the character reserved but
3393 has not yet been written. The <-- HERE shows in the regular expression about
3394 where the problem was discovered. See L<perlre>.
3396 =item Sequence (?%s...) not recognized in regex; marked by <-- HERE in m/%s/
3398 (F) You used a regular expression extension that doesn't make sense. The
3399 <-- HERE shows in the regular expression about where the problem was
3400 discovered. See L<perlre>.
3402 =item Sequence (?#... not terminated in regex; marked by <-- HERE in m/%s/
3404 (F) A regular expression comment must be terminated by a closing
3405 parenthesis. Embedded parentheses aren't allowed. The <-- HERE shows in
3406 the regular expression about where the problem was discovered. See
3409 =item Sequence (?{...}) not terminated or not {}-balanced in regex; marked by <-- HERE in m/%s/
3411 (F) If the contents of a (?{...}) clause contains braces, they must balance
3412 for Perl to properly detect the end of the clause. The <-- HERE shows in
3413 the regular expression about where the problem was discovered. See
3416 =item 500 Server error
3422 This is the error message generally seen in a browser window when trying
3423 to run a CGI program (including SSI) over the web. The actual error text
3424 varies widely from server to server. The most frequently-seen variants
3425 are "500 Server error", "Method (something) not permitted", "Document
3426 contains no data", "Premature end of script headers", and "Did not
3427 produce a valid header".
3429 B<This is a CGI error, not a Perl error>.
3431 You need to make sure your script is executable, is accessible by the
3432 user CGI is running the script under (which is probably not the user
3433 account you tested it under), does not rely on any environment variables
3434 (like PATH) from the user it isn't running under, and isn't in a
3435 location where the CGI server can't find it, basically, more or less.
3436 Please see the following for more information:
3438 http://www.perl.org/CGI_MetaFAQ.html
3439 http://www.htmlhelp.org/faq/cgifaq.html
3440 http://www.w3.org/Security/Faq/
3442 You should also look at L<perlfaq9>.
3444 =item setegid() not implemented
3446 (F) You tried to assign to C<$)>, and your operating system doesn't
3447 support the setegid() system call (or equivalent), or at least Configure
3450 =item seteuid() not implemented
3452 (F) You tried to assign to C<< $> >>, and your operating system doesn't
3453 support the seteuid() system call (or equivalent), or at least Configure
3456 =item setpgrp can't take arguments
3458 (F) Your system has the setpgrp() from BSD 4.2, which takes no
3459 arguments, unlike POSIX setpgid(), which takes a process ID and process
3462 =item setrgid() not implemented
3464 (F) You tried to assign to C<$(>, and your operating system doesn't
3465 support the setrgid() system call (or equivalent), or at least Configure
3468 =item setruid() not implemented
3470 (F) You tried to assign to C<$<>, and your operating system doesn't
3471 support the setruid() system call (or equivalent), or at least Configure
3474 =item setsockopt() on closed socket %s
3476 (W closed) You tried to set a socket option on a closed socket. Did you
3477 forget to check the return value of your socket() call? See
3478 L<perlfunc/setsockopt>.
3480 =item Setuid/gid script is writable by world
3482 (F) The setuid emulator won't run a script that is writable by the
3483 world, because the world might have written on it already.
3485 =item shm%s not implemented
3487 (F) You don't have System V shared memory IPC on your system.
3489 =item !=~ should be !~
3491 (W syntax) The non-matching operator is !~, not !=~. !=~ will be
3492 interpreted as the != (numeric not equal) and ~ (1's complement)
3493 operators: probably not what you intended.
3495 =item <> should be quotes
3497 (F) You wrote C<< require <file> >> when you should have written
3500 =item /%s/ should probably be written as "%s"
3502 (W syntax) You have used a pattern where Perl expected to find a string,
3503 as in the first argument to C<join>. Perl will treat the true or false
3504 result of matching the pattern against $_ as the string, which is
3505 probably not what you had in mind.
3507 =item shutdown() on closed socket %s
3509 (W closed) You tried to do a shutdown on a closed socket. Seems a bit
3512 =item SIG%s handler "%s" not defined
3514 (W signal) The signal handler named in %SIG doesn't, in fact, exist.
3515 Perhaps you put it into the wrong package?
3517 =item sort is now a reserved word
3519 (F) An ancient error message that almost nobody ever runs into anymore.
3520 But before sort was a keyword, people sometimes used it as a filehandle.
3522 =item Sort subroutine didn't return a numeric value
3524 (F) A sort comparison routine must return a number. You probably blew
3525 it by not using C<< <=> >> or C<cmp>, or by not using them correctly.
3526 See L<perlfunc/sort>.
3528 =item Sort subroutine didn't return single value
3530 (F) A sort comparison subroutine may not return a list value with more
3531 or less than one element. See L<perlfunc/sort>.
3533 =item splice() offset past end of array
3535 (W misc) You attempted to specify an offset that was past the end of
3536 the array passed to splice(). Splicing will instead commence at the end
3537 of the array, rather than past it. If this isn't what you want, try
3538 explicitly pre-extending the array by assigning $#array = $offset. See
3543 (P) The split was looping infinitely. (Obviously, a split shouldn't
3544 iterate more times than there are characters of input, which is what
3545 happened.) See L<perlfunc/split>.
3547 =item Statement unlikely to be reached
3549 (W exec) You did an exec() with some statement after it other than a
3550 die(). This is almost always an error, because exec() never returns
3551 unless there was a failure. You probably wanted to use system()
3552 instead, which does return. To suppress this warning, put the exec() in
3555 =item stat() on unopened filehandle %s
3557 (W unopened) You tried to use the stat() function on a filehandle that
3558 was either never opened or has since been closed.
3560 =item Stub found while resolving method `%s' overloading %s
3562 (P) Overloading resolution over @ISA tree may be broken by importation
3563 stubs. Stubs should never be implicitly created, but explicit calls to
3564 C<can> may break this.
3566 =item Subroutine %s redefined
3568 (W redefine) You redefined a subroutine. To suppress this warning, say
3571 no warnings 'redefine';
3572 eval "sub name { ... }";
3575 =item Substitution loop
3577 (P) The substitution was looping infinitely. (Obviously, a substitution
3578 shouldn't iterate more times than there are characters of input, which
3579 is what happened.) See the discussion of substitution in
3580 L<perlop/"Quote and Quote-like Operators">.
3582 =item Substitution pattern not terminated
3584 (F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
3585 construct. Remember that bracketing delimiters count nesting level.
3586 Missing the leading C<$> from variable C<$s> may cause this error.
3588 =item Substitution replacement not terminated
3590 (F) The lexer couldn't find the final delimiter of an s/// or s{}{}
3591 construct. Remember that bracketing delimiters count nesting level.
3592 Missing the leading C<$> from variable C<$s> may cause this error.
3594 =item substr outside of string
3596 (W substr),(F) You tried to reference a substr() that pointed outside of
3597 a string. That is, the absolute value of the offset was larger than the
3598 length of the string. See L<perlfunc/substr>. This warning is fatal if
3599 substr is used in an lvalue context (as the left hand side of an
3600 assignment or as a subroutine argument for example).
3602 =item suidperl is no longer needed since %s
3604 (F) Your Perl was compiled with B<-D>SETUID_SCRIPTS_ARE_SECURE_NOW, but
3605 a version of the setuid emulator somehow got run anyway.
3607 =item Switch (?(condition)... contains too many branches in regex; marked by <-- HERE in m/%s/
3609 (F) A (?(condition)if-clause|else-clause) construct can have at most two
3610 branches (the if-clause and the else-clause). If you want one or both to
3611 contain alternation, such as using C<this|that|other>, enclose it in
3612 clustering parentheses:
3614 (?(condition)(?:this|that|other)|else-clause)
3616 The <-- HERE shows in the regular expression about where the problem was
3617 discovered. See L<perlre>.
3619 =item Switch condition not recognized in regex; marked by <-- HERE in m/%s/
3621 (F) If the argument to the (?(...)if-clause|else-clause) construct is a
3622 number, it can be only a number. The <-- HERE shows in the regular expression
3623 about where the problem was discovered. See L<perlre>.
3625 =item switching effective %s is not implemented
3627 (F) While under the C<use filetest> pragma, we cannot switch the real
3628 and effective uids or gids.
3632 (F) The final summary message when a C<perl -c> succeeds.
3636 (F) Probably means you had a syntax error. Common reasons include:
3638 A keyword is misspelled.
3639 A semicolon is missing.
3641 An opening or closing parenthesis is missing.
3642 An opening or closing brace is missing.
3643 A closing quote is missing.
3645 Often there will be another error message associated with the syntax
3646 error giving more information. (Sometimes it helps to turn on B<-w>.)
3647 The error message itself often tells you where it was in the line when
3648 it decided to give up. Sometimes the actual error is several tokens
3649 before this, because Perl is good at understanding random input.
3650 Occasionally the line number may be misleading, and once in a blue moon
3651 the only way to figure out what's triggering the error is to call
3652 C<perl -c> repeatedly, chopping away half the program each time to see
3653 if the error went away. Sort of the cybernetic version of S<20
3656 =item syntax error at line %d: `%s' unexpected
3658 (A) You've accidentally run your script through the Bourne shell instead
3659 of Perl. Check the #! line, or manually feed your script into Perl
3662 =item syntax error in file %s at line %d, next 2 tokens "%s"
3664 (F) This error is likely to occur if you run a perl5 script through
3665 a perl4 interpreter, especially if the next 2 tokens are "use strict"
3666 or "my $var" or "our $var".
3668 =item sysread() on closed filehandle %s
3670 (W closed) You tried to read from a closed filehandle.
3672 =item sysread() on unopened filehandle %s
3674 (W unopened) You tried to read from a filehandle that was never opened.
3676 =item System V %s is not implemented on this machine
3678 (F) You tried to do something with a function beginning with "sem",
3679 "shm", or "msg" but that System V IPC is not implemented in your
3680 machine. In some machines the functionality can exist but be
3681 unconfigured. Consult your system support.
3683 =item syswrite() on closed filehandle %s
3685 (W closed) The filehandle you're writing to got itself closed sometime
3686 before now. Check your control flow.
3688 =item C<-T> and C<-B> not implemented on filehandles
3690 (F) Perl can't peek at the stdio buffer of filehandles when it doesn't
3691 know about your kind of stdio. You'll have to use a filename instead.
3693 =item Target of goto is too deeply nested
3695 (F) You tried to use C<goto> to reach a label that was too deeply nested
3696 for Perl to reach. Perl is doing you a favor by refusing.
3698 =item tell() on unopened filehandle
3700 (W unopened) You tried to use the tell() function on a filehandle that
3701 was either never opened or has since been closed.
3703 =item That use of $[ is unsupported
3705 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
3706 as a compiler directive. You may say only one of
3715 This is to prevent the problem of one module changing the array base out
3716 from under another module inadvertently. See L<perlvar/$[>.
3718 =item The crypt() function is unimplemented due to excessive paranoia
3720 (F) Configure couldn't find the crypt() function on your machine,
3721 probably because your vendor didn't supply it, probably because they
3722 think the U.S. Government thinks it's a secret, or at least that they
3723 will continue to pretend that it is. And if you quote me on that, I
3726 =item The %s function is unimplemented
3728 The function indicated isn't implemented on this architecture, according
3729 to the probings of Configure.
3731 =item The stat preceding %s wasn't an lstat
3733 (F) It makes no sense to test the current stat buffer for symbolic
3734 linkhood if the last stat that wrote to the stat buffer already went
3735 past the symlink to get to the real file. Use an actual filename
3738 =item The 'unique' attribute may only be applied to 'our' variables
3740 (F) Currently this attribute is not supported on C<my> or C<sub>
3741 declarations. See L<perlfunc/our>.
3743 =item This Perl can't reset CRTL environ elements (%s)
3745 =item This Perl can't set CRTL environ elements (%s=%s)
3747 (W internal) Warnings peculiar to VMS. You tried to change or delete an
3748 element of the CRTL's internal environ array, but your copy of Perl
3749 wasn't built with a CRTL that contained the setenv() function. You'll
3750 need to rebuild Perl with a CRTL that does, or redefine
3751 F<PERL_ENV_TABLES> (see L<perlvms>) so that the environ array isn't the
3752 target of the change to
3753 %ENV which produced the warning.
3755 =item thread failed to start: %s
3757 (F) The entry point function of threads->create() failed for some reason.
3759 =item times not implemented
3761 (F) Your version of the C library apparently doesn't do times(). I
3762 suspect you're not running on Unix.
3764 =item To%s: illegal mapping '%s'
3766 (F) You tried to define a customized To-mapping for lc(), lcfirst,
3767 uc(), or ucfirst() (or their string-inlined versions), but you
3768 specified an illegal mapping.
3769 See L<perlunicode/"User-Defined Character Properties">.
3771 =item Too deeply nested ()-groups
3773 (F) Your template contains ()-groups with a ridiculously deep nesting level.
3775 =item Too few args to syscall
3777 (F) There has to be at least one argument to syscall() to specify the
3778 system call to call, silly dilly.
3780 =item Too late for "-%s" option
3782 (X) The #! line (or local equivalent) in a Perl script contains the
3783 B<-M> or B<-m> option. This is an error because B<-M> and B<-m> options
3784 are not intended for use inside scripts. Use the C<use> pragma instead.
3786 =item Too late for "B<-T>" option
3788 (X) The #! line (or local equivalent) in a Perl script contains the
3789 B<-T> option, but Perl was not invoked with B<-T> in its command line.
3790 This is an error because, by the time Perl discovers a B<-T> in a
3791 script, it's too late to properly taint everything from the environment.
3794 If the Perl script is being executed as a command using the #!
3795 mechanism (or its local equivalent), this error can usually be fixed by
3796 editing the #! line so that the B<-T> option is a part of Perl's first
3797 argument: e.g. change C<perl -n -T> to C<perl -T -n>.
3799 If the Perl script is being executed as C<perl scriptname>, then the
3800 B<-T> option must appear on the command line: C<perl -T scriptname>.
3802 =item Too late to run %s block
3804 (W void) A CHECK or INIT block is being defined during run time proper,
3805 when the opportunity to run them has already passed. Perhaps you are
3806 loading a file with C<require> or C<do> when you should be using C<use>
3807 instead. Or perhaps you should put the C<require> or C<do> inside a
3810 =item Too many args to syscall
3812 (F) Perl supports a maximum of only 14 args to syscall().
3814 =item Too many arguments for %s
3816 (F) The function requires fewer arguments than you specified.
3820 (A) You've accidentally run your script through B<csh> instead of Perl.
3821 Check the #! line, or manually feed your script into Perl yourself.
3825 (A) You've accidentally run your script through B<csh> instead of Perl.
3826 Check the #! line, or manually feed your script into Perl yourself.
3828 =item Trailing \ in regex m/%s/
3830 (F) The regular expression ends with an unbackslashed backslash.
3831 Backslash it. See L<perlre>.
3833 =item Transliteration pattern not terminated
3835 (F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
3836 or y/// or y[][] construct. Missing the leading C<$> from variables
3837 C<$tr> or C<$y> may cause this error.
3839 =item Transliteration replacement not terminated
3841 (F) The lexer couldn't find the final delimiter of a tr///, tr[][],
3842 y/// or y[][] construct.
3844 =item '%s' trapped by operation mask
3846 (F) You tried to use an operator from a Safe compartment in which it's
3847 disallowed. See L<Safe>.
3849 =item truncate not implemented
3851 (F) Your machine doesn't implement a file truncation mechanism that
3852 Configure knows about.
3854 =item Type of arg %d to %s must be %s (not %s)
3856 (F) This function requires the argument in that position to be of a
3857 certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be
3858 %NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
3859 {EXPR} forms as an explicit dereference. See L<perlref>.
3861 =item umask not implemented
3863 (F) Your machine doesn't implement the umask function and you tried to
3864 use it to restrict permissions for yourself (EXPR & 0700).
3866 =item Unable to create sub named "%s"
3868 (F) You attempted to create or access a subroutine with an illegal name.
3870 =item Unbalanced context: %d more PUSHes than POPs
3872 (W internal) The exit code detected an internal inconsistency in how
3873 many execution contexts were entered and left.
3875 =item Unbalanced saves: %d more saves than restores
3877 (W internal) The exit code detected an internal inconsistency in how
3878 many values were temporarily localized.
3880 =item Unbalanced scopes: %d more ENTERs than LEAVEs
3882 (W internal) The exit code detected an internal inconsistency in how
3883 many blocks were entered and left.
3885 =item Unbalanced tmps: %d more allocs than frees
3887 (W internal) The exit code detected an internal inconsistency in how
3888 many mortal scalars were allocated and freed.
3890 =item Undefined format "%s" called
3892 (F) The format indicated doesn't seem to exist. Perhaps it's really in
3893 another package? See L<perlform>.
3895 =item Undefined sort subroutine "%s" called
3897 (F) The sort comparison routine specified doesn't seem to exist.
3898 Perhaps it's in a different package? See L<perlfunc/sort>.
3900 =item Undefined subroutine &%s called
3902 (F) The subroutine indicated hasn't been defined, or if it was, it has
3903 since been undefined.
3905 =item Undefined subroutine called
3907 (F) The anonymous subroutine you're trying to call hasn't been defined,
3908 or if it was, it has since been undefined.
3910 =item Undefined subroutine in sort
3912 (F) The sort comparison routine specified is declared but doesn't seem
3913 to have been defined yet. See L<perlfunc/sort>.
3915 =item Undefined top format "%s" called
3917 (F) The format indicated doesn't seem to exist. Perhaps it's really in
3918 another package? See L<perlform>.
3920 =item Undefined value assigned to typeglob
3922 (W misc) An undefined value was assigned to a typeglob, a la
3923 C<*foo = undef>. This does nothing. It's possible that you really mean
3926 =item %s: Undefined variable
3928 (A) You've accidentally run your script through B<csh> instead of Perl.
3929 Check the #! line, or manually feed your script into Perl yourself.
3931 =item unexec of %s into %s failed!
3933 (F) The unexec() routine failed for some reason. See your local FSF
3934 representative, who probably put it there in the first place.
3936 =item Unicode character %s is illegal
3938 (W utf8) Certain Unicode characters have been designated off-limits by
3939 the Unicode standard and should not be generated. If you really know
3940 what you are doing you can turn off this warning by C<no warnings 'utf8';>.
3942 =item Unknown BYTEORDER
3944 (F) There are no byte-swapping functions for a machine with this byte
3947 =item Unknown open() mode '%s'
3949 (F) The second argument of 3-argument open() is not among the list
3950 of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
3951 C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
3953 =item Unknown PerlIO layer "%s"
3955 (W layer) An attempt was made to push an unknown layer onto the Perl I/O
3956 system. (Layers take care of transforming data between external and
3957 internal representations.) Note that some layers, such as C<mmap>,
3958 are not supported in all environments. If your program didn't
3959 explicitly request the failing operation, it may be the result of the
3960 value of the environment variable PERLIO.
3962 =item Unknown process %x sent message to prime_env_iter: %s
3964 (P) An error peculiar to VMS. Perl was reading values for %ENV before
3965 iterating over it, and someone else stuck a message in the stream of
3966 data Perl expected. Someone's very confused, or perhaps trying to
3967 subvert Perl's population of %ENV for nefarious purposes.
3969 =item Unknown "re" subpragma '%s' (known ones are: %s)
3971 You tried to use an unknown subpragma of the "re" pragma.
3973 =item Unknown switch condition (?(%.2s in regex; marked by <-- HERE in m/%s/
3975 (F) The condition part of a (?(condition)if-clause|else-clause) construct
3976 is not known. The condition may be lookahead or lookbehind (the condition
3977 is true if the lookahead or lookbehind is true), a (?{...}) construct (the
3978 condition is true if the code evaluates to a true value), or a number (the
3979 condition is true if the set of capturing parentheses named by the number
3982 The <-- HERE shows in the regular expression about where the problem was
3983 discovered. See L<perlre>.
3985 =item Unknown Unicode option letter '%c'
3987 You specified an unknown Unicode option. See L<perlrun> documentation
3988 of the C<-C> switch for the list of known options.
3990 =item Unknown Unicode option value %x
3992 You specified an unknown Unicode option. See L<perlrun> documentation
3993 of the C<-C> switch for the list of known options.
3995 =item Unknown warnings category '%s'
3997 (F) An error issued by the C<warnings> pragma. You specified a warnings
3998 category that is unknown to perl at this point.
4000 Note that if you want to enable a warnings category registered by a module
4001 (e.g. C<use warnings 'File::Find'>), you must have imported this module
4004 =item unmatched [ in regex; marked by <-- HERE in m/%s/
4006 (F) The brackets around a character class must match. If you wish to
4007 include a closing bracket in a character class, backslash it or put it
4008 first. The <-- HERE shows in the regular expression about where the problem
4009 was discovered. See L<perlre>.
4011 =item unmatched ( in regex; marked by <-- HERE in m/%s/
4013 (F) Unbackslashed parentheses must always be balanced in regular
4014 expressions. If you're a vi user, the % key is valuable for finding the
4015 matching parenthesis. The <-- HERE shows in the regular expression about
4016 where the problem was discovered. See L<perlre>.
4018 =item Unmatched right %s bracket
4020 (F) The lexer counted more closing curly or square brackets than opening
4021 ones, so you're probably missing a matching opening bracket. As a
4022 general rule, you'll find the missing one (so to speak) near the place
4023 you were last editing.
4025 =item Unquoted string "%s" may clash with future reserved word
4027 (W reserved) You used a bareword that might someday be claimed as a
4028 reserved word. It's best to put such a word in quotes, or capitalize it
4029 somehow, or insert an underbar into it. You might also declare it as a
4032 =item Unrecognized character %s
4034 (F) The Perl parser has no idea what to do with the specified character
4035 in your Perl script (or eval). Perhaps you tried to run a compressed
4036 script, a binary program, or a directory as a Perl program.
4038 =item /%s/: Unrecognized escape \\%c in character class passed through
4040 (W regexp) You used a backslash-character combination which is not
4041 recognized by Perl inside character classes. The character was
4042 understood literally.
4044 =item Unrecognized escape \\%c passed through
4046 (W misc) You used a backslash-character combination which is not
4049 =item Unrecognized escape \\%c passed through in regex; marked by <-- HERE in m/%s/
4051 (W regexp) You used a backslash-character combination which is not
4052 recognized by Perl. This combination appears in an interpolated variable or
4053 a C<'>-delimited regular expression. The character was understood
4054 literally. The <-- HERE shows in the regular expression about where the
4055 escape was discovered.
4057 =item Unrecognized signal name "%s"
4059 (F) You specified a signal name to the kill() function that was not
4060 recognized. Say C<kill -l> in your shell to see the valid signal names
4063 =item Unrecognized switch: -%s (-h will show valid options)
4065 (F) You specified an illegal option to Perl. Don't do that. (If you
4066 think you didn't do that, check the #! line to see if it's supplying the
4067 bad switch on your behalf.)
4069 =item Unsuccessful %s on filename containing newline
4071 (W newline) A file operation was attempted on a filename, and that
4072 operation failed, PROBABLY because the filename contained a newline,
4073 PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
4075 =item Unsupported directory function "%s" called
4077 (F) Your machine doesn't support opendir() and readdir().
4079 =item Unsupported function %s
4081 (F) This machine doesn't implement the indicated function, apparently.
4082 At least, Configure doesn't think so.
4084 =item Unsupported function fork
4086 (F) Your version of executable does not support forking.
4088 Note that under some systems, like OS/2, there may be different flavors
4089 of Perl executables, some of which may support fork, some not. Try
4090 changing the name you call Perl by to C<perl_>, C<perl__>, and so on.
4092 =item Unsupported script encoding %s
4094 (F) Your program file begins with a Unicode Byte Order Mark (BOM) which
4095 declares it to be in a Unicode encoding that Perl cannot read.
4097 =item Unsupported socket function "%s" called
4099 (F) Your machine doesn't support the Berkeley socket mechanism, or at
4100 least that's what Configure thought.
4102 =item Unterminated attribute list
4104 (F) The lexer found something other than a simple identifier at the
4105 start of an attribute, and it wasn't a semicolon or the start of a
4106 block. Perhaps you terminated the parameter list of the previous
4107 attribute too soon. See L<attributes>.
4109 =item Unterminated attribute parameter in attribute list
4111 (F) The lexer saw an opening (left) parenthesis character while parsing
4112 an attribute list, but the matching closing (right) parenthesis
4113 character was not found. You may need to add (or remove) a backslash
4114 character to get your parentheses to balance. See L<attributes>.
4116 =item Unterminated compressed integer
4118 (F) An argument to unpack("w",...) was incompatible with the BER
4119 compressed integer format and could not be converted to an integer.
4120 See L<perlfunc/pack>.
4122 =item Unterminated <> operator
4124 (F) The lexer saw a left angle bracket in a place where it was expecting
4125 a term, so it's looking for the corresponding right angle bracket, and
4126 not finding it. Chances are you left some needed parentheses out
4127 earlier in the line, and you really meant a "less than".
4129 =item untie attempted while %d inner references still exist
4131 (W untie) A copy of the object returned from C<tie> (or C<tied>) was
4132 still valid when C<untie> was called.
4134 =item Usage: POSIX::%s(%s)
4136 (F) You called a POSIX function with incorrect arguments.
4137 See L<POSIX/FUNCTIONS> for more information.
4139 =item Usage: Win32::%s(%s)
4141 (F) You called a Win32 function with incorrect arguments.
4142 See L<Win32> for more information.
4144 =item Useless (?-%s) - don't use /%s modifier in regex; marked by <-- HERE in m/%s/
4146 (W regexp) You have used an internal modifier such as (?-o) that has no
4147 meaning unless removed from the entire regexp:
4149 if ($string =~ /(?-o)$pattern/o) { ... }
4153 if ($string =~ /$pattern/) { ... }
4155 The <-- HERE shows in the regular expression about
4156 where the problem was discovered. See L<perlre>.
4158 =item Useless localization of %s
4160 (W syntax) The localization of lvalues such as C<local($x=10)> is
4161 legal, but in fact the local() currently has no effect. This may change at
4162 some point in the future, but in the meantime such code is discouraged.
4164 =item Useless (?%s) - use /%s modifier in regex; marked by <-- HERE in m/%s/
4166 (W regexp) You have used an internal modifier such as (?o) that has no
4167 meaning unless applied to the entire regexp:
4169 if ($string =~ /(?o)$pattern/) { ... }
4173 if ($string =~ /$pattern/o) { ... }
4175 The <-- HERE shows in the regular expression about
4176 where the problem was discovered. See L<perlre>.
4178 =item Useless use of %s in void context
4180 (W void) You did something without a side effect in a context that does
4181 nothing with the return value, such as a statement that doesn't return a
4182 value from a block, or the left side of a scalar comma operator. Very
4183 often this points not to stupidity on your part, but a failure of Perl
4184 to parse your program the way you thought it would. For example, you'd
4185 get this if you mixed up your C precedence with Python precedence and
4190 when you meant to say
4192 ($one, $two) = (1, 2);
4194 Another common error is to use ordinary parentheses to construct a list
4195 reference when you should be using square or curly brackets, for
4200 when you should have said
4204 The square brackets explicitly turn a list value into a scalar value,
4205 while parentheses do not. So when a parenthesized list is evaluated in
4206 a scalar context, the comma is treated like C's comma operator, which
4207 throws away the left argument, which is not what you want. See
4208 L<perlref> for more on this.
4210 This warning will not be issued for numerical constants equal to 0 or 1
4211 since they are often used in statements like
4213 1 while sub_with_side_effects() ;
4215 String constants that would normally evaluate to 0 or 1 are warned
4218 =item Useless use of "re" pragma
4220 (W) You did C<use re;> without any arguments. That isn't very useful.
4222 =item Useless use of sort in scalar context
4224 (W void) You used sort in scalar context, as in :
4228 This is not very useful, and perl currently optimizes this away.
4230 =item Useless use of %s with no values
4232 (W syntax) You used the push() or unshift() function with no arguments
4233 apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
4234 usually have any effect on the array, so is completely useless. It's
4235 possible in principle that push(@tied_array) could have some effect
4236 if the array is tied to a class which implements a PUSH method. If so,
4237 you can write it as C<push(@tied_array,())> to avoid this warning.
4239 =item "use" not allowed in expression
4241 (F) The "use" keyword is recognized and executed at compile time, and
4242 returns no useful value. See L<perlmod>.
4244 =item Use of bare << to mean <<"" is deprecated
4246 (D deprecated) You are now encouraged to use the explicitly quoted form
4247 if you wish to use an empty line as the terminator of the here-document.
4249 =item Use of chdir('') or chdir(undef) as chdir() deprecated
4251 (D deprecated) chdir() with no arguments is documented to change to
4252 $ENV{HOME} or $ENV{LOGDIR}. chdir(undef) and chdir('') share this
4253 behavior, but that has been deprecated. In future versions they
4256 Be careful to check that what you pass to chdir() is defined and not
4257 blank, else you might find yourself in your home directory.
4259 =item Use of /c modifier is meaningless in s///
4261 (W regexp) You used the /c modifier in a substitution. The /c
4262 modifier is not presently meaningful in substitutions.
4264 =item Use of /c modifier is meaningless without /g
4266 (W regexp) You used the /c modifier with a regex operand, but didn't
4267 use the /g modifier. Currently, /c is meaningful only when /g is
4268 used. (This may change in the future.)
4270 =item Use of freed value in iteration
4272 (F) Perhaps you modified the iterated array within the loop?
4273 This error is typically caused by code like the following:
4276 @a = () for (1,2,@a);
4278 You are not supposed to modify arrays while they are being iterated over.
4279 For speed and efficiency reasons, Perl internally does not do full
4280 reference-counting of iterated items, hence deleting such an item in the
4281 middle of an iteration causes Perl to see a freed value.
4283 =item Use of *glob{FILEHANDLE} is deprecated
4285 (D deprecated) You are now encouraged to use the shorter *glob{IO} form
4286 to access the filehandle slot within a typeglob.
4288 =item Use of /g modifier is meaningless in split
4290 (W regexp) You used the /g modifier on the pattern for a C<split>
4291 operator. Since C<split> always tries to match the pattern
4292 repeatedly, the C</g> has no effect.
4294 =item Use of implicit split to @_ is deprecated
4296 (D deprecated) It makes a lot of work for the compiler when you clobber
4297 a subroutine's argument list, so it's better if you assign the results
4298 of a split() explicitly to an array (or list).
4300 =item Use of inherited AUTOLOAD for non-method %s() is deprecated
4302 (D deprecated) As an (ahem) accidental feature, C<AUTOLOAD> subroutines
4303 are looked up as methods (using the C<@ISA> hierarchy) even when the
4304 subroutines to be autoloaded were called as plain functions (e.g.
4305 C<Foo::bar()>), not as methods (e.g. C<< Foo->bar() >> or C<<
4308 This bug will be rectified in future by using method lookup only for
4309 methods' C<AUTOLOAD>s. However, there is a significant base of existing
4310 code that may be using the old behavior. So, as an interim step, Perl
4311 currently issues an optional warning when non-methods use inherited
4314 The simple rule is: Inheritance will not work when autoloading
4315 non-methods. The simple fix for old code is: In any module that used
4316 to depend on inheriting C<AUTOLOAD> for non-methods from a base class
4317 named C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during
4320 In code that currently says C<use AutoLoader; @ISA = qw(AutoLoader);>
4321 you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
4322 C<use AutoLoader 'AUTOLOAD';>.
4324 =item Use of %s in printf format not supported
4326 (F) You attempted to use a feature of printf that is accessible from
4327 only C. This usually means there's a better way to do it in Perl.
4329 =item Use of $# is deprecated
4331 (D deprecated) This was an ill-advised attempt to emulate a poorly
4332 defined B<awk> feature. Use an explicit printf() or sprintf() instead.
4334 =item Use of %s is deprecated
4336 (D deprecated) The construct indicated is no longer recommended for use,
4337 generally because there's a better way to do it, and also because the
4338 old way has bad side effects.
4340 =item Use of -l on filehandle %s
4342 (W io) A filehandle represents an opened file, and when you opened the file
4343 it already went past any symlink you are presumably trying to look for.
4344 The operation returned C<undef>. Use a filename instead.
4346 =item Deprecated use of my() in false conditional
4348 (D deprecated) You used a declaration similar to C<my $x if 0>.
4349 There has been a long-standing bug in Perl that causes a lexical variable
4350 not to be cleared at scope exit when its declaration includes a false
4351 conditional. Some people have exploited this bug to achieve a kind of
4352 static variable. Since we intend to fix this bug, we don't want people
4353 relying on this behavior. You can achieve a similar static effect by
4354 declaring the variable in a separate block outside the function, eg
4356 sub f { my $x if 0; return $x++ }
4360 { my $x; sub f { return $x++ } }
4362 =item Use of "package" with no arguments is deprecated
4364 (D deprecated) You used the C<package> keyword without specifying a package
4365 name. So no namespace is current at all. Using this can cause many
4366 otherwise reasonable constructs to fail in baffling ways. C<use strict;>
4369 =item Use of reference "%s" as array index
4371 (W misc) You tried to use a reference as an array index; this probably
4372 isn't what you mean, because references in numerical context tend
4373 to be huge numbers, and so usually indicates programmer error.
4375 If you really do mean it, explicitly numify your reference, like so:
4376 C<$array[0+$ref]>. This warning is not given for overloaded objects,
4377 either, because you can overload the numification and stringification
4378 operators and then you assumedly know what you are doing.
4380 =item Use of reserved word "%s" is deprecated
4382 (D deprecated) The indicated bareword is a reserved word. Future
4383 versions of perl may use it as a keyword, so you're better off either
4384 explicitly quoting the word in a manner appropriate for its context of
4385 use, or using a different name altogether. The warning can be
4386 suppressed for subroutine names by either adding a C<&> prefix, or using
4387 a package qualifier, e.g. C<&our()>, or C<Foo::our()>.
4389 =item Use of tainted arguments in %s is deprecated
4391 (W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
4392 arguments and at least one of them is tainted. This used to be allowed
4393 but will become a fatal error in a future version of perl. Untaint your
4394 arguments. See L<perlsec>.
4396 =item Use of uninitialized value%s
4398 (W uninitialized) An undefined value was used as if it were already
4399 defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
4400 To suppress this warning assign a defined value to your variables.
4402 To help you figure out what was undefined, perl will try to tell you the
4403 name of the variable (if any) that was undefined. In some cases it cannot
4404 do this, so it also tells you what operation you used the undefined value
4405 in. Note, however, that perl optimizes your program and the operation
4406 displayed in the warning may not necessarily appear literally in your
4407 program. For example, C<"that $foo"> is usually optimized into C<"that "
4408 . $foo>, and the warning will refer to the C<concatenation (.)> operator,
4409 even though there is no C<.> in your program.
4411 =item Using a hash as a reference is deprecated
4413 (D deprecated) You tried to use a hash as a reference, as in
4414 C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl <= 5.6.1
4415 used to allow this syntax, but shouldn't have. It is now deprecated, and will
4416 be removed in a future version.
4418 =item Using an array as a reference is deprecated
4420 (D deprecated) You tried to use an array as a reference, as in
4421 C<< @foo->[23] >> or C<< @$ref->[99] >>. Versions of perl <= 5.6.1 used to
4422 allow this syntax, but shouldn't have. It is now deprecated, and will be
4423 removed in a future version.
4425 =item UTF-16 surrogate %s
4427 (W utf8) You tried to generate half of an UTF-16 surrogate by
4428 requesting a Unicode character between the code points 0xD800 and
4429 0xDFFF (inclusive). That range is reserved exclusively for the use of
4430 UTF-16 encoding (by having two 16-bit UCS-2 characters); but Perl
4431 encodes its characters in UTF-8, so what you got is a very illegal
4432 character. If you really know what you are doing you can turn off
4433 this warning by C<no warnings 'utf8';>.
4435 =item Value of %s can be "0"; test with defined()
4437 (W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
4438 C<each()>, or C<readdir()> as a boolean value. Each of these constructs
4439 can return a value of "0"; that would make the conditional expression
4440 false, which is probably not what you intended. When using these
4441 constructs in conditional expressions, test their values with the
4442 C<defined> operator.
4444 =item Value of CLI symbol "%s" too long
4446 (W misc) A warning peculiar to VMS. Perl tried to read the value of an
4447 %ENV element from a CLI symbol table, and found a resultant string
4448 longer than 1024 characters. The return value has been truncated to
4451 =item Variable "%s" is not available
4453 (W closure) During compilation, an inner named subroutine or eval is
4454 attempting to capture an outer lexical that is not currently available.
4455 This can happen for one of two reasons. First, the outer lexical may be
4456 declared in an outer anonymous subroutine that has not yet been created.
4457 (Remember that named subs are created at compile time, while anonymous
4458 subs are created at run-time.) For example,
4460 sub { my $a; sub f { $a } }
4462 At the time that f is created, it can't capture the current value of $a,
4463 since the anonymous subroutine hasn't been created yet. Conversely,
4464 the following won't give a warning since the anonymous subroutine has by
4465 now been created and is live:
4467 sub { my $a; eval 'sub f { $a }' }->();
4469 The second situation is caused by an eval accessing a variable that has
4470 gone out of scope, for example,
4478 Here, when the '$a' in the eval is being compiled, f() is not currently being
4479 executed, so its $a is not available for capture.
4481 =item Variable "%s" is not imported%s
4483 (F) While "use strict" in effect, you referred to a global variable that
4484 you apparently thought was imported from another module, because
4485 something else of the same name (usually a subroutine) is exported by
4486 that module. It usually means you put the wrong funny character on the
4487 front of your variable.
4489 =item Variable length lookbehind not implemented in regex; marked by <-- HERE in m/%s/
4491 (F) Lookbehind is allowed only for subexpressions whose length is fixed and
4492 known at compile time. The <-- HERE shows in the regular expression about
4493 where the problem was discovered. See L<perlre>.
4495 =item "%s" variable %s masks earlier declaration in same %s
4497 (W misc) A "my" or "our" variable has been redeclared in the current
4498 scope or statement, effectively eliminating all access to the previous
4499 instance. This is almost always a typographical error. Note that the
4500 earlier variable will still exist until the end of the scope or until
4501 all closure referents to it are destroyed.
4503 =item Variable syntax
4505 (A) You've accidentally run your script through B<csh> instead
4506 of Perl. Check the #! line, or manually feed your script into
4509 =item Variable "%s" will not stay shared
4511 (W closure) An inner (nested) I<named> subroutine is referencing a
4512 lexical variable defined in an outer named subroutine.
4514 When the inner subroutine is called, it will see the value of
4515 the outer subroutine's variable as it was before and during the *first*
4516 call to the outer subroutine; in this case, after the first call to the
4517 outer subroutine is complete, the inner and outer subroutines will no
4518 longer share a common value for the variable. In other words, the
4519 variable will no longer be shared.
4521 This problem can usually be solved by making the inner subroutine
4522 anonymous, using the C<sub {}> syntax. When inner anonymous subs that
4523 reference variables in outer subroutines are created, they
4524 are automatically rebound to the current values of such variables.
4526 =item Version number must be a constant number
4528 (P) The attempt to translate a C<use Module n.n LIST> statement into
4529 its equivalent C<BEGIN> block found an internal inconsistency with
4532 =item v-string in use/require is non-portable
4534 (W portable) The use of v-strings is non-portable to older, pre-5.6, Perls.
4535 If you want your scripts to be backward portable, use the floating
4536 point version number: for example, instead of C<use 5.6.1> say
4537 C<use 5.006_001>. This of course won't help: the older Perls
4538 won't suddenly start understanding newer features, but at least
4539 they will show a sensible error message indicating the required
4542 =item Warning: something's wrong
4544 (W) You passed warn() an empty string (the equivalent of C<warn "">) or
4545 you called it with no args and C<$_> was empty.
4547 =item Warning: unable to close filehandle %s properly
4549 (S) The implicit close() done by an open() got an error indication on
4550 the close(). This usually indicates your file system ran out of disk
4553 =item Warning: Use of "%s" without parentheses is ambiguous
4555 (S ambiguous) You wrote a unary operator followed by something that
4556 looks like a binary operator that could also have been interpreted as a
4557 term or unary operator. For instance, if you know that the rand
4558 function has a default argument of 1.0, and you write
4562 you may THINK you wrote the same thing as
4566 but in actual fact, you got
4570 So put in parentheses to say what you really mean.
4572 =item Wide character in %s
4574 (W utf8) Perl met a wide character (>255) when it wasn't expecting
4575 one. This warning is by default on for I/O (like print). The easiest
4576 way to quiet this warning is simply to add the C<:utf8> layer to the
4577 output, e.g. C<binmode STDOUT, ':utf8'>. Another way to turn off the
4578 warning is to add C<no warnings 'utf8';> but that is often closer to
4579 cheating. In general, you are supposed to explicitly mark the
4580 filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
4582 =item Within []-length '%c' not allowed
4584 (F) The count in the (un)pack template may be replaced by C<[TEMPLATE]> only if
4585 C<TEMPLATE> always matches the same amount of packed bytes that can be
4586 determined from the template alone. This is not possible if it contains an
4587 of the codes @, /, U, u, w or a *-length. Redesign the template.
4589 =item write() on closed filehandle %s
4591 (W closed) The filehandle you're writing to got itself closed sometime
4592 before now. Check your control flow.
4594 =item %s "\x%s" does not map to Unicode
4596 When reading in different encodings Perl tries to map everything
4597 into Unicode characters. The bytes you read in are not legal in
4598 this encoding, for example
4600 utf8 "\xE4" does not map to Unicode
4602 if you try to read in the a-diaereses Latin-1 as UTF-8.
4604 =item 'X' outside of string
4606 (F) You had a (un)pack template that specified a relative position before
4607 the beginning of the string being (un)packed. See L<perlfunc/pack>.
4609 =item 'x' outside of string in unpack
4611 (F) You had a pack template that specified a relative position after
4612 the end of the string being unpacked. See L<perlfunc/pack>.
4614 =item Xsub "%s" called in sort
4616 (F) The use of an external subroutine as a sort comparison is not yet
4619 =item Xsub called in sort
4621 (F) The use of an external subroutine as a sort comparison is not yet
4624 =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
4626 (F) And you probably never will, because you probably don't have the
4627 sources to your kernel, and your vendor probably doesn't give a rip
4628 about what you want. Your best bet is to put a setuid C wrapper around
4631 =item You need to quote "%s"
4633 (W syntax) You assigned a bareword as a signal handler name.
4634 Unfortunately, you already have a subroutine of that name declared,
4635 which means that Perl 5 will try to call the subroutine when the
4636 assignment is executed, which is probably not what you want. (If it IS
4637 what you want, put an & in front.)
4639 =item Your random numbers are not that random
4641 (F) When trying to initialise the random seed for hashes, Perl could
4642 not get any randomness out of your system. This usually indicates
4643 Something Very Wrong.