perldiag (1) Linux Manual Page

NAME

perldiag – various Perl diagnostics

DESCRIPTION

These messages are classified as follows (listed in increasing order of desperation):

    (W) A warning (optional).
    (D) A deprecation (enabled by default).
    (S) A severe warning (enabled by default).
    (F) A fatal error (trappable).
    (P) An internal error you should never see (trappable).
    (X) A very fatal error (nontrappable).
    (A) An alien error message (not generated by Perl).

The majority of messages from the first three classifications above (W, D & S) can be controlled using the "warnings" pragma.

If a message can be controlled by the "warnings" pragma, its warning category is included with the classification letter in the description below. E.g. "(W closed)" means a warning in the "closed" category.

Optional warnings are enabled by using the "warnings" pragma or the -w and -W switches. Warnings may be captured by setting $SIG{__WARN__} to a reference to a routine that will be called on each warning instead of printing it. See perlvar.

Severe warnings are always enabled, unless they are explicitly disabled with the "warnings" pragma or the -X switch.

Trappable errors may be trapped using the eval operator. See “eval” in perlfunc. In almost all cases, warnings may be selectively disabled or promoted to fatal errors using the "warnings" pragma. See warnings.

The messages are in alphabetical order, without regard to upper or lower-case. Some of these messages are generic. Spots that vary are denoted with a %s or other printf-style escape. These escapes are ignored by the alphabetical order, as are all characters other than letters. To look up your message, just ignore anything that is not a letter.

accept() on closed socket %s

(W closed) You tried to do an accept on a closed socket. Did you forget to check the return value of your socket() call? See “accept” in perlfunc.

Aliasing via reference is experimental

(S experimental::refaliasing) This warning is emitted if you use a reference constructor on the left-hand side of an assignment to alias one variable to another. Simply suppress the warning if you want to use the feature, but know that in doing so you are taking the risk of using an experimental feature which may change or be removed in a future Perl version:

    no warnings "experimental::refaliasing";
    use feature "refaliasing";
    \$x = \$y;

Allocation too large: %x

(X) You can’t allocate more than 64K on an MS-DOS machine.

‘%c’ allowed only after types %s in %s

(F) The modifiers ‘!’, ‘<‘ and ‘>’ are allowed in pack() or unpack() only after certain types. See “pack” in perlfunc.

alpha->numify() is lossy

(W numeric) An alpha version can not be numified without losing information.

Ambiguous call resolved as CORE::%s(), qualify as such or use &

(W ambiguous) A subroutine you have declared has the same name as a Perl keyword, and you have used the name without qualification for calling one or the other. Perl decided to call the builtin because the subroutine is not imported.

To force interpretation as a subroutine call, either put an ampersand before the subroutine name, or qualify the name with its package. Alternatively, you can import the subroutine (or pretend that it’s imported with the "use subs" pragma).

To silently interpret it as the Perl operator, use the "CORE::" prefix on the operator (e.g. "CORE::log($x)") or declare the subroutine to be an object method (see “Subroutine Attributes” in perlsub or attributes).

Ambiguous range in transliteration operator

(F) You wrote something like "tr/a-z-0//" which doesn’t mean anything at all. To include a "-" character in a transliteration, put it either first or last. (In the past, "tr/a-z-0//" was synonymous with "tr/a-y//", which was probably not what you would have expected.)

Ambiguous use of %s resolved as %s

(S ambiguous) You said something that may not be interpreted the way you thought. Normally it’s pretty easy to disambiguate it by supplying a missing quote, operator, parenthesis pair or declaration.

Ambiguous use of -%s resolved as -&%s()

(S ambiguous) You wrote something like "-foo", which might be the string "-foo", or a call to the function "foo", negated. If you meant the string, just write "-foo". If you meant the function call, write "-foo()".

Ambiguous use of %c resolved as operator %c

(S ambiguous) "%", "&", and "*" are both infix operators (modulus, bitwise and, and multiplication) and initial special characters (denoting hashes, subroutines and typeglobs), and you said something like "*foo * foo" that might be interpreted as either of them. We assumed you meant the infix operator, but please try to make it more clear — in the example given, you might write "*foo * foo()" if you really meant to multiply a glob by the result of calling a function.

Ambiguous use of %c{%s} resolved to %c%s

(W ambiguous) You wrote something like "@{foo}", which might be asking for the variable @foo, or it might be calling a function named foo, and dereferencing it as an array reference. If you wanted the variable, you can just write @foo. If you wanted to call the function, write "@{foo()}" … or you could just not have a variable and a function with the same name, and save yourself a lot of trouble.

Ambiguous use of %c{%s[…]} resolved to %c%s[…]

Ambiguous use of %c{%s{…}} resolved to %c%s{…}

(W ambiguous) You wrote something like "${foo[2]}" (where foo represents the name of a Perl keyword), which might be looking for element number 2 of the array named @foo, in which case please write $foo[2], or you might have meant to pass an anonymous arrayref to the function named foo, and then do a scalar deref on the value it returns. If you meant that, write "${foo([2])}".

In regular expressions, the "${foo[2]}" syntax is sometimes necessary to disambiguate between array subscripts and character classes. "/$length[2345]/", for instance, will be interpreted as $length followed by the character class "[2345]". If an array subscript is what you want, you can avoid the warning by changing "/${length[2345]}/" to the unsightly "/${\$length[2345]}/", by renaming your array to something that does not coincide with a built-in keyword, or by simply turning off warnings with "no warnings 'ambiguous';".

‘|’ and ‘<‘ may not both be specified on command line

(F) An error peculiar to VMS. Perl does its own command line redirection, and found that STDIN was a pipe, and that you also tried to redirect STDIN using ‘<‘. Only one STDIN stream to a customer, please.

‘|’ and ‘>’ may not both be specified on command line

(F) An error peculiar to VMS. Perl does its own command line redirection, and thinks you tried to redirect stdout both to a file and into a pipe to another command. You need to choose one or the other, though nothing’s stopping you from piping into a program or Perl script which ‘splits’ output into two streams, such as

open(OUT, ">$ARGV[0]") or die "Can't write to $ARGV[0]: $!";
while (<STDIN>) {
    print;
    print OUT;
}
close OUT;

Applying %s to %s will act on scalar(%s)

(W misc) The pattern match ("//"), substitution ("s///"), and transliteration ("tr///") operators work on scalar values. If you apply one of them to an array or a hash, it will convert the array or hash to a scalar value (the length of an array, or the population info of a hash) and then work on that scalar value. This is probably not what you meant to do. See “grep” in perlfunc and “map” in perlfunc for alternatives.

Arg too short for msgsnd

(F) msgsnd() requires a string at least as long as sizeof(long).

Argument "%s" isn’t numeric%s

(W numeric) The indicated string was fed as an argument to an operator that expected a numeric value instead. If you’re fortunate the message will identify which operator was so unfortunate.

Note that for the "Inf" and "NaN" (infinity and not-a-number) the definition of “numeric” is somewhat unusual: the strings themselves (like “Inf”) are considered numeric, and anything following them is considered non-numeric.

Argument list not closed for PerlIO layer "%s"

(W layer) When pushing a layer with arguments onto the Perl I/O system you forgot the ) that closes the argument list. (Layers take care of transforming data between external and internal representations.) Perl stopped parsing the layer list at this point and did not attempt to push this layer. If your program didn’t explicitly request the failing operation, it may be the result of the value of the environment variable PERLIO.

Argument "%s" treated as 0 in increment (++)

(W numeric) The indicated string was fed as an argument to the "++" operator which expects either a number or a string matching "/^[a-zA-Z]*[0-9]*\z/". See “Auto-increment and Auto-decrement” in perlop for details.

Array passed to stat will be coerced to a scalar%s

(W syntax) You called stat() on an array, but the array will be coerced to a scalar – the number of elements in the array.

A signature parameter must start with ‘$’, ‘@’ or ‘%’

(F) Each subroutine signature parameter declaration must start with a valid sigil; for example:

    sub foo ($a, $, $b = 1, @c) {}

A slurpy parameter may not have a default value

(F) Only scalar subroutine signature parameters may have a default value; for example:

sub foo($a = 1)
{
}
#legal sub foo(@a = (1))
{
}
#invalid sub foo(% a = (a = > b))
{
}
#invalid

assertion botched: %s

(X) The malloc package that comes with Perl had an internal failure.

Assertion %s failed: file "%s", line %d

(X) A general assertion failed. The file in question must be examined.

Assigned value is not a reference

(F) You tried to assign something that was not a reference to an lvalue reference (e.g., "\$x = $y"). If you meant to make $x an alias to $y, use "\$x = \$y".

Assigned value is not %s reference

(F) You tried to assign a reference to a reference constructor, but the two references were not of the same type. You cannot alias a scalar to an array, or an array to a hash; the two types must match.

\$x = \@y;
#error \@x = \%y;
#error $y = [];
\$x = $y;
#error;
did you mean \$y ?

Assigning non-zero to $[ is no longer possible

(F) When the “array_base” feature is disabled (e.g., and under "use v5.16;", and as of Perl 5.30) the special variable $[, which is deprecated, is now a fixed zero value.

Assignment to both a list and a scalar

(F) If you assign to a conditional operator, the 2nd and 3rd arguments must either both be scalars or both be lists. Otherwise Perl won’t know which context to supply to the right side.

Assuming NOT a POSIX class since %s in regex; marked by <– HERE in m/%s/

(W regexp) You had something like these:

[[:alnum]]
[[:digit:xyz]

They look like they might have been meant to be the POSIX classes "[:alnum:]" or "[:digit:]". If so, they should be written:

[[:alnum:]]
[[:digit:] xyz]

Since these aren’t legal POSIX class specifications, but are legal bracketed character classes, Perl treats them as the latter. In the first example, it matches the characters ":", "[", "a", "l", "m", "n", and "u".

If these weren’t meant to be POSIX classes, this warning message is spurious, and can be suppressed by reordering things, such as

[[al:num]]

or

[[:munla]]

<> at require-statement should be quotes

(F) You wrote "require <file>" when you should have written "require 'file'".

Attempt to access disallowed key ‘%s’ in a restricted hash

(F) The failing code has attempted to get or set a key which is not in the current set of allowed keys of a restricted hash.

Attempt to bless into a freed package

(F) You wrote "bless $foo" with one argument after somehow causing the current package to be freed. Perl cannot figure out what to do, so it throws up its hands in despair.

Attempt to bless into a reference

(F) The CLASSNAME argument to the bless() operator is expected to be the name of the package to bless the resulting object into. You’ve supplied instead a reference to something: perhaps you wrote

    bless $self, $proto;

when you intended

    bless $self, ref($proto) || $proto;

If you actually want to bless into the stringified version of the reference supplied, you need to stringify it yourself, for example by:

    bless $self, "$proto";

Attempt to clear deleted array

(S debugging) An array was assigned to when it was being freed. Freed values are not supposed to be visible to Perl code. This can also happen if XS code calls "av_clear" from a custom magic callback on the array.

Attempt to delete disallowed key ‘%s’ from a restricted hash

(F) The failing code attempted to delete from a restricted hash a key which is not in its key set.

Attempt to delete readonly key ‘%s’ from a restricted hash

(F) The failing code attempted to delete a key whose value has been declared readonly from a restricted hash.

Attempt to free non-arena SV: 0x%x

(S internal) All SV objects are supposed to be allocated from arenas that will be garbage collected on exit. An SV was discovered to be outside any of those arenas.

Attempt to free nonexistent shared string ‘%s’%s

(S internal) Perl maintains a reference-counted internal table of strings to optimize the storage and access of hash keys and other strings. This indicates someone tried to decrement the reference count of a string that can no longer be found in the table.

Attempt to free temp prematurely: SV 0x%x

(S debugging) Mortalized values are supposed to be freed by the free_tmps() routine. This indicates that something else is freeing the SV before the free_tmps() routine gets a chance, which means that the free_tmps() routine will be freeing an unreferenced scalar when it does try to free it.

Attempt to free unreferenced glob pointers

(S internal) The reference counts got screwed up on symbol aliases.

Attempt to free unreferenced scalar: SV 0x%x

(S internal) Perl went to decrement the reference count of a scalar to see if it would go to 0, and discovered that it had already gone to 0 earlier, and should have been freed, and in fact, probably was freed. This could indicate that SvREFCNT_dec() was called too many times, or that SvREFCNT_inc() was called too few times, or that the SV was mortalized when it shouldn’t have been, or that memory has been corrupted.

Attempt to pack pointer to temporary value

(W pack) You tried to pass a temporary value (like the result of a function, or a computed expression) to the “p” pack() template. This means the result contains a pointer to a location that could become invalid anytime, even before the end of the current statement. Use literals or global values as arguments to the “p” pack() template to avoid this warning.

Attempt to reload %s aborted.

(F) You tried to load a file with "use" or "require" that failed to compile once already. Perl will not try to compile this file again unless you delete its entry from %INC. See “require” in perlfunc and “%INC” in perlvar.

Attempt to set length of freed array

(W misc) You tried to set the length of an array which has been freed. You can do this by storing a reference to the scalar representing the last index of an array and later assigning through that reference. For example

$r = do
{
my @a;
\$ #a
};
$$r = 503

Attempt to use reference as lvalue in substr

(W substr) You supplied a reference as the first argument to substr() used as an lvalue, which is pretty strange. Perhaps you forgot to dereference it first. See “substr” in perlfunc.

Attribute prototype(%s) discards earlier prototype attribute in same sub

(W misc) A sub was declared as sub foo : prototype(A) : prototype(B) {}, for example. Since each sub can only have one prototype, the earlier declaration(s) are discarded while the last one is applied.

av_reify called on tied array

(S debugging) This indicates that something went wrong and Perl got very confused about @_ or @DB::args being tied.

Bad arg length for %s, is %u, should be %d

(F) You passed a buffer of the wrong size to one of msgctl(), semctl() or shmctl(). In C parlance, the correct sizes are, respectively, sizeof(struct msqid_ds *), sizeof(struct semid_ds *), and sizeof(struct shmid_ds *).

Bad evalled substitution pattern

(F) You’ve used the "/e" switch to evaluate the replacement for a substitution, but perl found a syntax error in the code to evaluate, most likely an unexpected right brace ‘}’.

Bad filehandle: %s

(F) A symbol was passed to something wanting a filehandle, but the symbol has no filehandle associated with it. Perhaps you didn’t do an open(), or did it in another package.

Bad free() ignored

(S malloc) An internal routine called free() on something that had never been malloc()ed in the first place. Mandatory, but can be disabled by setting environment variable "PERL_BADFREE" to 0.

This message can be seen quite often with DB_File on systems with “hard” dynamic linking, like "AIX" and "OS/2". It is a bug of "Berkeley DB" which is left unnoticed if "DB" uses forgiving system malloc().

Bad hash

(P) One of the internal hash routines was passed a null HV pointer.

Badly placed ()’s

(A) You’ve accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.

Bad name after %s

(F) You started to name a symbol by using a package prefix, and then didn’t finish the symbol. In particular, you can’t interpolate outside of quotes, so

    $var = 'myvar';
    $sym = mypack::$var;

is not the same as

    $var = 'myvar';
    $sym = "mypack::$var";

Bad plugin affecting keyword ‘%s’

(F) An extension using the keyword plugin mechanism violated the plugin API.

Bad realloc() ignored

(S malloc) An internal routine called realloc() on something that had never been malloc()ed in the first place. Mandatory, but can be disabled by setting the environment variable "PERL_BADFREE" to 1.

Bad symbol for array

(P) An internal request asked to add an array entry to something that wasn’t a symbol table entry.

Bad symbol for dirhandle

(P) An internal request asked to add a dirhandle entry to something that wasn’t a symbol table entry.

Bad symbol for filehandle

(P) An internal request asked to add a filehandle entry to something that wasn’t a symbol table entry.

Bad symbol for hash

(P) An internal request asked to add a hash entry to something that wasn’t a symbol table entry.

Bad symbol for scalar

(P) An internal request asked to add a scalar entry to something that wasn’t a symbol table entry.

Bareword found in conditional

(W bareword) The compiler found a bareword where it expected a conditional, which often indicates that an || or && was parsed as part of the last argument of the previous construct, for example:

    open FOO || die;

It may also indicate a misspelled constant that has been interpreted as a bareword:

use constant TYPO = > 1;
if (TYOP) {
print “foo”
}

The "strict" pragma is useful in avoiding such errors.

Bareword in require contains "%s"

Bareword in require maps to disallowed filename "%s"

Bareword in require maps to empty filename

(F) The bareword form of require has been invoked with a filename which could not have been generated by a valid bareword permitted by the parser. You shouldn’t be able to get this error from Perl code, but XS code may throw it if it passes an invalid module name to "Perl_load_module".

Bareword in require must not start with a double-colon: "%s"

(F) In "require Bare::Word", the bareword is not allowed to start with a double-colon. Write "require ::Foo::Bar" as "require Foo::Bar" instead.

Bareword "%s" not allowed while "strict subs" in use

(F) With “strict subs” in use, a bareword is only allowed as a subroutine identifier, in curly brackets or to the left of the “=>” symbol. Perhaps you need to predeclare a subroutine?

Bareword "%s" refers to nonexistent package

(W bareword) You used a qualified bareword of the form "Foo::", but the compiler saw no other uses of that namespace before that point. Perhaps you need to predeclare a package?

BEGIN failed—compilation aborted

(F) An untrapped exception was raised while executing a BEGIN subroutine. Compilation stops immediately and the interpreter is exited.

BEGIN not safe after errors—compilation aborted

(F) Perl found a "BEGIN {}" subroutine (or a "use" directive, which implies a "BEGIN {}") after one or more compilation errors had already occurred. Since the intended environment for the "BEGIN {}" could not be guaranteed (due to the errors), and since subsequent code likely depends on its correct operation, Perl just gave up.

\%d better written as $%d

(W syntax) Outside of patterns, backreferences live on as variables. The use of backslashes is grandfathered on the right-hand side of a substitution, but stylistically it’s better to use the variable form because other Perl programmers will expect it, and it works better if there are more than 9 backreferences.

Binary number > 0b11111111111111111111111111111111 non-portable

(W portable) The binary number you specified is larger than 2**32-1 (4294967295) and therefore non-portable between systems. See perlport for more on portability concerns.

bind() on closed socket %s

(W closed) You tried to do a bind on a closed socket. Did you forget to check the return value of your socket() call? See “bind” in perlfunc.

binmode() on closed filehandle %s

(W unopened) You tried binmode() on a filehandle that was never opened. Check your control flow and number of arguments.

Bit vector size > 32 non-portable

(W portable) Using bit vector sizes larger than 32 is non-portable.

Bizarre copy of %s

(P) Perl detected an attempt to copy an internal value that is not copiable.

Bizarre SvTYPE [%d]

(P) When starting a new thread or returning values from a thread, Perl encountered an invalid data type.

Both or neither range ends should be Unicode in regex; marked by <– HERE in m/%s/

(W regexp) (only under "use re 'strict'" or within "(?[...])")

In a bracketed character class in a regular expression pattern, you had a range which has exactly one end of it specified using "\N{}", and the other end is specified using a non-portable mechanism. Perl treats the range as a Unicode range, that is, all the characters in it are considered to be the Unicode characters, and which may be different code points on some platforms Perl runs on. For example, "[\N{U+06}-]" is treated as if you had instead said "[\N{U+06}-\N{U+08}]", that is it matches the characters whose code points in Unicode are 6, 7, and 8. But that "" might indicate that you meant something different, so the warning gets raised.

Buffer overflow in prime_env_iter: %s

(W internal) A warning peculiar to VMS. While Perl was preparing to iterate over %ENV, it encountered a logical name or symbol definition which was too long, so it was truncated to the string shown.

Callback called exit

(F) A subroutine invoked from an external package via call_sv() exited by calling exit.

%s() called too early to check prototype

(W prototype) You’ve called a function that has a prototype before the parser saw a definition or declaration for it, and Perl could not check that the call conforms to the prototype. You need to either add an early prototype declaration for the subroutine in question, or move the subroutine definition ahead of the call to get proper prototype checking. Alternatively, if you are certain that you’re calling the function correctly, you may put an ampersand before the name to avoid the warning. See perlsub.

Cannot chr %f

(F) You passed an invalid number (like an infinity or not-a-number) to "chr".

Cannot complete in-place edit of %s: %s

(F) Your perl script appears to have changed directory while performing an in-place edit of a file specified by a relative path, and your system doesn’t include the directory relative POSIX functions needed to handle that.

Cannot compress %f in pack

(F) You tried compressing an infinity or not-a-number as an unsigned integer with BER, which makes no sense.

Cannot compress integer in pack

(F) An argument to pack(“w”,…) was too large to compress. The BER compressed integer format can only be used with positive integers, and you attempted to compress a very large number (> 1e308). See “pack” in perlfunc.

Cannot compress negative numbers in pack

(F) An argument to pack(“w”,…) was negative. The BER compressed integer format can only be used with positive integers. See “pack” in perlfunc.

Cannot convert a reference to %s to typeglob

(F) You manipulated Perl’s symbol table directly, stored a reference in it, then tried to access that symbol via conventional Perl syntax. The access triggers Perl to autovivify that typeglob, but it there is no legal conversion from that type of reference to a typeglob.

Cannot copy to %s

(P) Perl detected an attempt to copy a value to an internal type that cannot be directly assigned to.

Cannot find encoding "%s"

(S io) You tried to apply an encoding that did not exist to a filehandle, either with open() or binmode().

Cannot open %s as a dirhandle: it is already open as a filehandle

(F) You tried to use opendir() to associate a dirhandle to a symbol (glob or scalar) that already holds a filehandle. Since this idiom might render your code confusing, it was deprecated in Perl 5.10. As of Perl 5.28, it is a fatal error.

Cannot open %s as a filehandle: it is already open as a dirhandle

(F) You tried to use open() to associate a filehandle to a symbol (glob or scalar) that already holds a dirhandle. Since this idiom might render your code confusing, it was deprecated in Perl 5.10. As of Perl 5.28, it is a fatal error.

Cannot pack %f with ‘%c’

(F) You tried converting an infinity or not-a-number to an integer, which makes no sense.

Cannot printf %f with ‘%c’

(F) You tried printing an infinity or not-a-number as a character (%c), which makes no sense. Maybe you meant ‘%s’, or just stringifying it?

Cannot set tied @DB::args

(F) "caller" tried to set @DB::args, but found it tied. Tying @DB::args is not supported. (Before this error was added, it used to crash.)

Cannot tie unreifiable array

(P) You somehow managed to call "tie" on an array that does not keep a reference count on its arguments and cannot be made to do so. Such arrays are not even supposed to be accessible to Perl code, but are only used internally.

Cannot yet reorder sv_vcatpvfn() arguments from va_list

(F) Some XS code tried to use "sv_vcatpvfn()" or a related function with a format string that specifies explicit indexes for some of the elements, and using a C-style variable-argument list (a "va_list"). This is not currently supported. XS authors wanting to do this must instead construct a C array of "SV*" scalars containing the arguments.

Can only compress unsigned integers in pack

(F) An argument to pack(“w”,…) was not an integer. The BER compressed integer format can only be used with positive integers, and you attempted to compress something else. See “pack” in perlfunc.

Can’t bless non-reference value

(F) Only hard references may be blessed. This is how Perl “enforces” encapsulation of objects. See perlobj.

Can’t "break" in a loop topicalizer

(F) You called "break", but you’re in a "foreach" block rather than a "given" block. You probably meant to use "next" or "last".

Can’t "break" outside a given block

(F) You called "break", but you’re not inside a "given" block.

Can’t call method "%s" on an undefined value

(F) You used the syntax of a method call, but the slot filled by the object reference or package name contains an undefined value. Something like this will reproduce the error:

$BADREF = undef;
process $BADREF 1, 2, 3;
$BADREF->process(1, 2, 3);

Can’t call method "%s" on unblessed reference

(F) A method call must know in what package it’s supposed to run. It ordinarily finds this out from the object reference you supply, but you didn’t supply an object reference in this case. A reference isn’t an object reference until it has been blessed. See perlobj.

Can’t call method "%s" without a package or object reference

(F) You used the syntax of a method call, but the slot filled by the object reference or package name contains an expression that returns a defined value which is neither an object reference nor a package name. Something like this will reproduce the error:

$BADREF = 42;
process $BADREF 1, 2, 3;
$BADREF->process(1, 2, 3);

Can’t call mro_isa_changed_in() on anonymous symbol table

(P) Perl got confused as to whether a hash was a plain hash or a symbol table hash when trying to update @ISA caches.

Can’t call mro_method_changed_in() on anonymous symbol table

(F) An XS module tried to call "mro_method_changed_in" on a hash that was not attached to the symbol table.

Can’t chdir to %s

(F) You called "perl -x/foo/bar", but /foo/bar is not a directory that you can chdir to, possibly because it doesn’t exist.

Can’t check filesystem of script "%s" for nosuid

(P) For some reason you can’t check the filesystem of the script for nosuid.

Can’t coerce %s to %s in %s

(F) Certain types of SVs, in particular real symbol table entries (typeglobs), can’t be forced to stop being what they are. So you can’t say things like:

    *foo += 1;

You CAN say

    $foo = *foo;
    $foo += 1;

but then $foo no longer contains a glob.

Can’t "continue" outside a when block

(F) You called "continue", but you’re not inside a "when" or "default" block.

Can’t create pipe mailbox

(P) An error peculiar to VMS. The process is suffering from exhausted quotas or other plumbing problems.

Can’t declare %s in "%s"

(F) Only scalar, array, and hash variables may be declared as “my”, “our” or “state” variables. They must have ordinary identifiers as names.

Can’t "default" outside a topicalizer

(F) You have used a "default" block that is neither inside a "foreach" loop nor a "given" block. (Note that this error is issued on exit from the "default" block, so you won’t get the error if you use an explicit "continue".)

Can’t determine class of operator %s, assuming BASEOP

(S) This warning indicates something wrong in the internals of perl. Perl was trying to find the class (e.g. LISTOP) of a particular OP, and was unable to do so. This is likely to be due to a bug in the perl internals, or due to a bug in XS code which manipulates perl optrees.

Can’t do inplace edit: %s is not a regular file

(S inplace) You tried to use the -i switch on a special file, such as a file in /dev, a FIFO or an uneditable directory. The file was ignored.

Can’t do inplace edit on %s: %s

(S inplace) The creation of the new file failed for the indicated reason.

Can’t do inplace edit: %s would not be unique

(S inplace) Your filesystem does not support filenames longer than 14 characters and Perl was unable to create a unique filename during inplace editing with the -i switch. The file was ignored.

Can’t do %s("%s") on non-UTF-8 locale; resolved to "%s".

(W locale) You are 1) running under ""use locale""; 2) the current locale is not a UTF-8 one; 3) you tried to do the designated case-change operation on the specified Unicode character; and 4) the result of this operation would mix Unicode and locale rules, which likely conflict. Mixing of different rule types is forbidden, so the operation was not done; instead the result is the indicated value, which is the best available that uses entirely Unicode rules. That turns out to almost always be the original character, unchanged.

It is generally a bad idea to mix non-UTF-8 locales and Unicode, and this issue is one of the reasons why. This warning is raised when Unicode rules would normally cause the result of this operation to contain a character that is in the range specified by the locale, 0..255, and hence is subject to the locale’s rules, not Unicode’s.

If you are using locale purely for its characteristics related to things like its numeric and time formatting (and not "LC_CTYPE"), consider using a restricted form of the locale pragma (see “The ”use locale“ pragma” in perllocale) like ""use locale ':not_characters'"".

Note that failed case-changing operations done as a result of case-insensitive "/i" regular expression matching will show up in this warning as having the "fc" operation (as that is what the regular expression engine calls behind the scenes.)

Can’t do waitpid with flags

(F) This machine doesn’t have either waitpid() or wait4(), so only waitpid() without flags is emulated.

Can’t emulate -%s on #! line

(F) The #! line specifies a switch that doesn’t make sense at this point. For example, it’d be kind of silly to put a -x on the #! line.

Can’t %s %s-endian %ss on this platform

(F) Your platform’s byte-order is neither big-endian nor little-endian, or it has a very strange pointer size. Packing and unpacking big- or little-endian floating point values and pointers may not be possible. See “pack” in perlfunc.

Can’t exec "%s": %s

(W exec) A system(), exec(), or piped open call could not execute the named program for the indicated reason. Typical reasons include: the permissions were wrong on the file, the file wasn’t found in $ENV{PATH}, the executable in question was compiled for another architecture, or the #! line in a script points to an interpreter that can’t be run for similar reasons. (Or maybe your system doesn’t support #! at all.)

Can’t exec %s

(F) Perl was trying to execute the indicated program for you because that’s what the #! line said. If that’s not what you wanted, you may need to mention “perl” on the #! line somewhere.

Can’t execute %s

(F) You used the -S switch, but the copies of the script to execute found in the PATH did not have correct permissions.

Can’t find an opnumber for "%s"

(F) A string of a form "CORE::word" was given to prototype(), but there is no builtin with the name "word".

Can’t find label %s

(F) You said to goto a label that isn’t mentioned anywhere that it’s possible for us to go to. See “goto” in perlfunc.

Can’t find %s on PATH

(F) You used the -S switch, but the script to execute could not be found in the PATH.

Can’t find %s on PATH, ‘.’ not in PATH

(F) You used the -S switch, but the script to execute could not be found in the PATH, or at least not with the correct permissions. The script exists in the current directory, but PATH prohibits running it.

Can’t find string terminator %s anywhere before EOF

(F) Perl strings can stretch over multiple lines. This message means that the closing delimiter was omitted. Because bracketed quotes count nesting levels, the following is missing its final parenthesis:

    print q(The character '(' starts a side comment.);

If you’re getting this error from a here-document, you may have included unseen whitespace before or after your closing tag or there may not be a linebreak after it. A good programmer’s editor will have a way to help you find these characters (or lack of characters). See perlop for the full details on here-documents.

Can’t find Unicode property definition "%s"

Can’t find Unicode property definition "%s" in regex; marked by <– HERE in m/%s/

(F) The named property which you specified via "\p" or "\P" is not one known to Perl. Perhaps you misspelled the name? See “Properties accessible through \p{} and \P{}” in perluniprops for a complete list of available official properties. If it is a user-defined property it must have been defined by the time the regular expression is matched.

If you didn’t mean to use a Unicode property, escape the "\p", either by "\p" (just the "\p") or by "\Q\p" (the rest of the string, or until "\E").

Can’t fork: %s

(F) A fatal error occurred while trying to fork while opening a pipeline.

Can’t fork, trying again in 5 seconds

(W pipe) A fork in a piped open failed with EAGAIN and will be retried after five seconds.

Can’t get filespec – stale stat buffer?

(S) A warning peculiar to VMS. This arises because of the difference between access checks under VMS and under the Unix model Perl assumes. Under VMS, access checks are done by filename, rather than by bits in the stat buffer, so that ACLs and other protections can be taken into account. Unfortunately, Perl assumes that the stat buffer contains all the necessary information, and passes it, instead of the filespec, to the access-checking routine. It will try to retrieve the filespec using the device name and FID present in the stat buffer, but this works only if you haven’t made a subsequent call to the CRTL stat() routine, because the device name is overwritten with each call. If this warning appears, the name lookup failed, and the access-checking routine gave up and returned FALSE, just to be conservative. (Note: The access-checking routine knows about the Perl "stat" operator and file tests, so you shouldn’t ever see this warning in response to a Perl command; it arises only if some internal code takes stat buffers lightly.)

Can’t get pipe mailbox device name

(P) An error peculiar to VMS. After creating a mailbox to act as a pipe, Perl can’t retrieve its name for later use.

Can’t get SYSGEN parameter value for MAXBUF

(P) An error peculiar to VMS. Perl asked $GETSYI how big you want your mailbox buffers to be, and didn’t get an answer.

Can’t "goto" into a binary or list expression

(F) A “goto” statement was executed to jump into the middle of a binary or list expression. You can’t get there from here. The reason for this restriction is that the interpreter would get confused as to how many arguments there are, resulting in stack corruption or crashes. This error occurs in cases such as these:

goto F;
print do {F : };
#Can’t jump into the arguments to print goto G;
$x + do {G : $y};
#How is + supposed to get its first operand ?

Can’t "goto" into a "given" block

(F) A “goto” statement was executed to jump into the middle of a "given" block. You can’t get there from here. See “goto” in perlfunc.

Can’t "goto" into the middle of a foreach loop

(F) A “goto” statement was executed to jump into the middle of a foreach loop. You can’t get there from here. See “goto” in perlfunc.

Can’t "goto" out of a pseudo block

(F) A “goto” statement was executed to jump out of what might look like a block, except that it isn’t a proper block. This usually occurs if you tried to jump out of a sort() block or subroutine, which is a no-no. See “goto” in perlfunc.

Can’t goto subroutine from an eval-%s

(F) The “goto subroutine” call can’t be used to jump out of an eval “string” or block.

Can’t goto subroutine from a sort sub (or similar callback)

(F) The “goto subroutine” call can’t be used to jump out of the comparison sub for a sort(), or from a similar callback (such as the reduce() function in List::Util).

Can’t goto subroutine outside a subroutine

(F) The deeply magical “goto subroutine” call can only replace one subroutine call for another. It can’t manufacture one out of whole cloth. In general you should be calling it out of only an AUTOLOAD routine anyway. See “goto” in perlfunc.

Can’t ignore signal CHLD, forcing to default

(W signal) Perl has detected that it is being run with the SIGCHLD signal (sometimes known as SIGCLD) disabled. Since disabling this signal will interfere with proper determination of exit status of child processes, Perl has reset the signal to its default value. This situation typically indicates that the parent program under which Perl may be running (e.g. cron) is being very careless.

Can’t kill a non-numeric process ID

(F) Process identifiers must be (signed) integers. It is a fatal error to attempt to kill() an undefined, empty-string or otherwise non-numeric process identifier.

Can’t "last" outside a loop block

(F) A “last” statement was executed to break out of the current block, except that there’s this itty bitty problem called there isn’t a current block. Note that an “if” or “else” block doesn’t count as a “loopish” block, as doesn’t a block given to sort(), map() or grep(). You can usually double the curlies to get the same effect though, because the inner curlies will be considered a block that loops once. See “last” in perlfunc.

Can’t linearize anonymous symbol table

(F) Perl tried to calculate the method resolution order (MRO) of a package, but failed because the package stash has no name.

Can’t load ‘%s’ for module %s

(F) The module you tried to load failed to load a dynamic extension. This may either mean that you upgraded your version of perl to one that is incompatible with your old dynamic extensions (which is known to happen between major versions of perl), or (more likely) that your dynamic extension was built against an older version of the library that is installed on your system. You may need to rebuild your old dynamic extensions.

Can’t localize lexical variable %s

(F) You used local on a variable name that was previously declared as a lexical variable using “my” or “state”. This is not allowed. If you want to localize a package variable of the same name, qualify it with the package name.

Can’t localize through a reference

(F) You said something like "local $$ref", which Perl can’t currently handle, because when it goes to restore the old value of whatever $ref pointed to after the scope of the local() is finished, it can’t be sure that $ref will still be a reference.

Can’t locate %s

(F) You said to "do" (or "require", or "use") a file that couldn’t be found. Perl looks for the file in all the locations mentioned in @INC, unless the file name included the full path to the file. Perhaps you need to set the PERL5LIB or PERL5OPT environment variable to say where the extra library is, or maybe the script needs to add the library name to @INC. Or maybe you just misspelled the name of the file. See “require” in perlfunc and lib.

Can’t locate auto/%s.al in @INC

(F) A function (or method) was called in a package which allows autoload, but there is no function to autoload. Most probable causes are a misprint in a function/method name or a failure to "AutoSplit" the file, say, by doing "make install".

Can’t locate loadable object for module %s in @INC

(F) The module you loaded is trying to load an external library, like for example, foo.so or bar.dll, but the DynaLoader module was unable to locate this library. See DynaLoader.

Can’t locate object method "%s" via package "%s"

(F) You called a method correctly, and it correctly indicated a package functioning as a class, but that package doesn’t define that particular method, nor does any of its base classes. See perlobj.

Can’t locate object method "%s" via package "%s" (perhaps you forgot to load "%s"?)

(F) You called a method on a class that did not exist, and the method could not be found in UNIVERSAL. This often means that a method requires a package that has not been loaded.

Can’t locate package %s for @%s::ISA

(W syntax) The @ISA array contained the name of another package that doesn’t seem to exist.

Can’t locate PerlIO%s

(F) You tried to use in open() a PerlIO layer that does not exist, e.g. open(FH, “>:nosuchlayer”, “somefile”).

Can’t make list assignment to %ENV on this system

(F) List assignment to %ENV is not supported on some systems, notably VMS.

Can’t make loaded symbols global on this platform while loading %s

(S) A module passed the flag 0x01 to DynaLoader::dl_load_file() to request that symbols from the stated file are made available globally within the process, but that functionality is not available on this platform. Whilst the module likely will still work, this may prevent the perl interpreter from loading other XS-based extensions which need to link directly to functions defined in the C or XS code in the stated file.

Can’t modify %s in %s

(F) You aren’t allowed to assign to the item indicated, or otherwise try to change it, such as with an auto-increment.

Can’t modify nonexistent substring

(P) The internal routine that does assignment to a substr() was handed a NULL.

Can’t modify non-lvalue subroutine call of &%s

Can’t modify non-lvalue subroutine call of &%s in %s

(F) Subroutines meant to be used in lvalue context should be declared as such. See “Lvalue subroutines” in perlsub.

Can’t modify reference to %s in %s assignment

(F) Only a limited number of constructs can be used as the argument to a reference constructor on the left-hand side of an assignment, and what you used was not one of them. See “Assigning to References” in perlref.

Can’t modify reference to localized parenthesized array in list assignment

(F) Assigning to "\local(@array)" or "\(local @array)" is not supported, as it is not clear exactly what it should do. If you meant to make @array refer to some other array, use "\@array = \@other_array". If you want to make the elements of @array aliases of the scalars referenced on the right-hand side, use "\(@array) = @scalar_refs".

Can’t modify reference to parenthesized hash in list assignment

(F) Assigning to "\(%hash)" is not supported. If you meant to make %hash refer to some other hash, use "\%hash = \%other_hash". If you want to make the elements of %hash into aliases of the scalars referenced on the right-hand side, use a hash slice: "\@hash{@keys} = @those_scalar_refs".

Can’t msgrcv to read-only var

(F) The target of a msgrcv must be modifiable to be used as a receive buffer.

Can’t "next" outside a loop block

(F) A “next” statement was executed to reiterate the current block, but there isn’t a current block. Note that an “if” or “else” block doesn’t count as a “loopish” block, as doesn’t a block given to sort(), map() or grep(). You can usually double the curlies to get the same effect though, because the inner curlies will be considered a block that loops once. See “next” in perlfunc.

Can’t open %s: %s

(S inplace) The implicit opening of a file through use of the "<>" filehandle, either implicitly under the "-n" or "-p" command-line switches, or explicitly, failed for the indicated reason. Usually this is because you don’t have read permission for a file which you named on the command line.

(F) You tried to call perl with the -e switch, but /dev/null (or your operating system’s equivalent) could not be opened.

Can’t open a reference

(W io) You tried to open a scalar reference for reading or writing, using the 3-arg open() syntax:

    open FH, '>', $ref;

but your version of perl is compiled without perlio, and this form of open is not supported.

Can’t open bidirectional pipe

(W pipe) You tried to say "open(CMD, "|cmd|")", which is not supported. You can try any of several modules in the Perl library to do this, such as IPC::Open2. Alternately, direct the pipe’s output to a file using “>”, and then read it in under a different file handle.

Can’t open error file %s as stderr

(F) An error peculiar to VMS. Perl does its own command line redirection, and couldn’t open the file specified after ‘2>’ or ‘2>>’ on the command line for writing.

Can’t open input file %s as stdin

(F) An error peculiar to VMS. Perl does its own command line redirection, and couldn’t open the file specified after ‘<‘ on the command line for reading.

Can’t open output file %s as stdout

(F) An error peculiar to VMS. Perl does its own command line redirection, and couldn’t open the file specified after ‘>’ or ‘>>’ on the command line for writing.

Can’t open output pipe (name: %s)

(P) An error peculiar to VMS. Perl does its own command line redirection, and couldn’t open the pipe into which to send data destined for stdout.

Can’t open perl script "%s": %s

(F) The script you specified can’t be opened for the indicated reason.

If you’re debugging a script that uses #!, and normally relies on the shell’s $PATH search, the -S option causes perl to do that search, so you don’t have to type the path or "`which $scriptname`".

Can’t read CRTL environ

(S) A warning peculiar to VMS. Perl tried to read an element of %ENV from the CRTL‘s internal environment array and discovered the array was missing. You need to figure out where your CRTL misplaced its environ or define PERL_ENV_TABLES (see perlvms) so that environ is not searched.

Can’t redeclare "%s" in "%s"

(F) A “my”, “our” or “state” declaration was found within another declaration, such as "my ($x, my($y), $z)" or "our (my $x)".

Can’t "redo" outside a loop block

(F) A “redo” statement was executed to restart the current block, but there isn’t a current block. Note that an “if” or “else” block doesn’t count as a “loopish” block, as doesn’t a block given to sort(), map() or grep(). You can usually double the curlies to get the same effect though, because the inner curlies will be considered a block that loops once. See “redo” in perlfunc.

Can’t remove %s: %s, skipping file

(S inplace) You requested an inplace edit without creating a backup file. Perl was unable to remove the original file to replace it with the modified file. The file was left unmodified.

Can’t rename in-place work file ‘%s’ to ‘%s’: %s

(F) When closed implicitly, the temporary file for in-place editing couldn’t be renamed to the original filename.

Can’t rename %s to %s: %s, skipping file

(F) The rename done by the -i switch failed for some reason, probably because you don’t have write permission to the directory.

Can’t reopen input pipe (name: %s) in binary mode

(P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried to reopen it to accept binary data. Alas, it failed.

Can’t represent character for Ox%X on this platform

(F) There is a hard limit to how big a character code point can be due to the fundamental properties of UTF-8, especially on EBCDIC platforms. The given code point exceeds that. The only work-around is to not use such a large code point.

Can’t reset %ENV on this system

(F) You called "reset('E')" or similar, which tried to reset all variables in the current package beginning with “E”. In the main package, that includes %ENV. Resetting %ENV is not supported on some systems, notably VMS.

Can’t resolve method "%s" overloading "%s" in package "%s"

(F)(P) Error resolving overloading specified by a method name (as opposed to a subroutine reference): no such method callable via the package. If the method name is "???", this is an internal error.

Can’t return %s from lvalue subroutine

(F) Perl detected an attempt to return illegal lvalues (such as temporary or readonly values) from a subroutine used as an lvalue. This is not allowed.

Can’t return outside a subroutine

(F) The return statement was executed in mainline code, that is, where there was no subroutine call to return out of. See perlsub.

Can’t return %s to lvalue scalar context

(F) You tried to return a complete array or hash from an lvalue subroutine, but you called the subroutine in a way that made Perl think you meant to return only one value. You probably meant to write parentheses around the call to the subroutine, which tell Perl that the call should be in list context.

Can’t stat script "%s"

(P) For some reason you can’t fstat() the script even though you have it open already. Bizarre.

Can’t take log of %g

(F) For ordinary real numbers, you can’t take the logarithm of a negative number or zero. There’s a Math::Complex package that comes standard with Perl, though, if you really want to do that for the negative numbers.

Can’t take sqrt of %g

(F) For ordinary real numbers, you can’t take the square root of a negative number. There’s a Math::Complex package that comes standard with Perl, though, if you really want to do that.

Can’t undef active subroutine

(F) You can’t undefine a routine that’s currently running. You can, however, redefine it while it’s running, and you can even undef the redefined subroutine while the old routine is running. Go figure.

Can’t unweaken a nonreference

(F) You attempted to unweaken something that was not a reference. Only references can be unweakened.

Can’t upgrade %s (%d) to %d

(P) The internal sv_upgrade routine adds “members” to an SV, making it into a more specialized kind of SV. The top several SV types are so specialized, however, that they cannot be interconverted. This message indicates that such a conversion was attempted.

Can’t use ‘%c’ after -mname

(F) You tried to call perl with the -m switch, but you put something other than “=” after the module name.

Can’t use a hash as a reference

(F) You tried to use a hash as a reference, as in "%foo->{"bar"}" or "%$ref->{"hello"}". Versions of perl <= 5.22.0 used to allow this syntax, but shouldn’t have. This was deprecated in perl 5.6.1.

Can’t use an array as a reference

(F) You tried to use an array as a reference, as in "@foo->[23]" or "@$ref->[99]". Versions of perl <= 5.22.0 used to allow this syntax, but shouldn’t have. This was deprecated in perl 5.6.1.

Can’t use anonymous symbol table for method lookup

(F) The internal routine that does method lookup was handed a symbol table that doesn’t have a name. Symbol tables can become anonymous for example by undefining stashes: "undef %Some::Package::".

Can’t use an undefined value as %s reference

(F) A value used as either a hard reference or a symbolic reference must be a defined value. This helps to delurk some insidious errors.

Can’t use bareword ("%s") as %s ref while "strict refs" in use

(F) Only hard references are allowed by “strict refs”. Symbolic references are disallowed. See perlref.

Can’t use %! because Errno.pm is not available

(F) The first time the "%!" hash is used, perl automatically loads the Errno.pm module. The Errno module is expected to tie the %! hash to provide symbolic names for $! errno values.

Can’t use both ‘<‘ and ‘>’ after type ‘%c’ in %s

(F) A type cannot be forced to have both big-endian and little-endian byte-order at the same time, so this combination of modifiers is not allowed. See “pack” in perlfunc.

Can’t use ‘defined(@array)’ (Maybe you should just omit the defined()?)

(F) defined() is not useful on arrays because it checks for an undefined scalar value. If you want to see if the array is empty, just use "if (@array) { # not empty }" for example.

Can’t use ‘defined(%hash)’ (Maybe you should just omit the defined()?)

(F) "defined()" is not usually right on hashes.

Although "defined %hash" is false on a plain not-yet-used hash, it becomes true in several non-obvious circumstances, including iterators, weak references, stash names, even remaining true after "undef %hash". These things make "defined %hash" fairly useless in practice, so it now generates a fatal error.

If a check for non-empty is what you wanted then just put it in boolean context (see “Scalar values” in perldata):

    if (%hash) {
       # not empty
    }

If you had "defined %Foo::Bar::QUUX" to check whether such a package variable exists then that’s never really been reliable, and isn’t a good way to enquire about the features of a package, or whether it’s loaded, etc.

Can’t use %s for loop variable

(P) The parser got confused when trying to parse a "foreach" loop.

Can’t use global %s in "%s"

(F) You tried to declare a magical variable as a lexical variable. This is not allowed, because the magic can be tied to only one location (namely the global variable) and it would be incredibly confusing to have variables in your program that looked like magical variables but weren’t.

Can’t use ‘%c’ in a group with different byte-order in %s

(F) You attempted to force a different byte-order on a type that is already inside a group with a byte-order modifier. For example you cannot force little-endianness on a type that is inside a big-endian group.

Can’t use "my %s" in sort comparison

(F) The global variables $a and $b are reserved for sort comparisons. You mentioned $a or $b in the same line as the <=> or cmp operator, and the variable had earlier been declared as a lexical variable. Either qualify the sort variable with the package name, or rename the lexical variable.

Can’t use %s ref as %s ref

(F) You’ve mixed up your reference types. You have to dereference a reference of the type needed. You can use the ref() function to test the type of the reference, if need be.

Can’t use string ("%s") as %s ref while "strict refs" in use

Can’t use string ("%s"…) as %s ref while "strict refs" in use

(F) You’ve told Perl to dereference a string, something which "use strict" blocks to prevent it happening accidentally. See “Symbolic references” in perlref. This can be triggered by an "@" or "$" in a double-quoted string immediately before interpolating a variable, for example in "user @$twitter_id", which says to treat the contents of $twitter_id as an array reference; use a "\" to have a literal "@" symbol followed by the contents of $twitter_id: "user \@$twitter_id".

Can’t use subscript on %s

(F) The compiler tried to interpret a bracketed expression as a subscript. But to the left of the brackets was an expression that didn’t look like a hash or array reference, or anything else subscriptable.

Can’t use \%c to mean $%c in expression

(W syntax) In an ordinary expression, backslash is a unary operator that creates a reference to its argument. The use of backslash to indicate a backreference to a matched substring is valid only as part of a regular expression pattern. Trying to do this in ordinary Perl code produces a value that prints out looking like SCALAR(0xdecaf). Use the $1 form instead.

Can’t weaken a nonreference

(F) You attempted to weaken something that was not a reference. Only references can be weakened.

Can’t "when" outside a topicalizer

(F) You have used a when() block that is neither inside a "foreach" loop nor a "given" block. (Note that this error is issued on exit from the "when" block, so you won’t get the error if the match fails, or if you use an explicit "continue".)

Can’t x= to read-only value

(F) You tried to repeat a constant value (often the undefined value) with an assignment operator, which implies modifying the value itself. Perhaps you need to copy the value to a temporary, and repeat that.

Character following "