perldiag - various Perl diagnostics
These messages are classified as follows (listed in increasing order of desperation):
- (W) A warning (optional).
- (D) A deprecation (optional).
- (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.
Optional warnings are enabled by using the warnings
pragma or the -w
and -W switches. Warnings may be captured by setting $SIG{__WARN__}
to a reference to a routine that will be called on each warning instead
of printing it. See perlvar.
Severe warnings are always enabled, unless they are explicitly disabled
with the warnings
pragma or the -X switch.
Trappable errors may be trapped using the eval operator. See
eval. In almost all cases, warnings may be selectively
disabled or promoted to fatal errors using the warnings
pragma.
See warnings.
The messages are in alphabetical order, without regard to upper or lower-case. Some of these messages are generic. Spots that vary are denoted with a %s or other printf-style escape. These escapes are ignored by the alphabetical order, as are all characters other than letters. To look up your message, just ignore anything that is not a letter.
(W closed) You tried to do an accept on a closed socket. Did you forget to check the return value of your socket() call? See accept.
(X) You can't allocate more than 64K on an MS-DOS machine.
(F) The '!' is allowed in pack() or unpack() only after certain types. See pack.
(W ambiguous) A subroutine you have declared has the same name as a Perl keyword, and you have used the name without qualification for calling one or the other. Perl decided to call the builtin because the subroutine is not imported.
To force interpretation as a subroutine call, either put an ampersand
before the subroutine name, or qualify the name with its package.
Alternatively, you can import the subroutine (or pretend that it's
imported with the use subs
pragma).
To silently interpret it as the Perl operator, use the CORE::
prefix
on the operator (e.g. CORE::log($x)
) or declare the subroutine
to be an object method (see Subroutine Attributes in perlsub or
attributes).
(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.)
(W ambiguous)(S) 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.
(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.
(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
(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 and map for
alternatives.
(F) The setuid emulator requires that the arguments Perl was invoked
with match the arguments specified on the #! line. Since some systems
impose a one-argument limit on the #! line, try combining switches;
for example, turn -w -U
into -wU
.
(F) msgsnd() requires a string at least as long as sizeof(long).
(F) The argument to exists() must be a hash or array element, such as:
- $foo{$bar}
- $ref->{"susie"}[12]
(F) The argument to delete() must be either a hash or array element, such as:
- $foo{$bar}
- $ref->{"susie"}[12]
or a hash or array slice, such as:
- @foo[$bar, $baz, $xyzzy]
- @{$ref->[12]}{"susie", "queue"}
(F) The argument to exists() for exists &sub
must be a subroutine
name, and not a subroutine call. exists &sub()
will generate this
error.
(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.
(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.
(D deprecated) Really old Perl let you omit the @ on array names in some spots. This is now heavily deprecated.
(P) The malloc package that comes with Perl had an internal failure.
(P) A general assertion failed. The file in question must be examined.
(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.
(W threads)(S) When using threaded Perl, a thread (not necessarily the main thread) exited while there were still other threads running. Usually it's a good idea to first collect the return values of the created threads by joining them, and only then exit from the main thread. See threads.
(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.
(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
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";
(F) The failing code attempted to delete from a restricted hash a key which is not in its key set.
(F) The failing code attempted to delete a key whose value has been declared readonly from a restricted hash.
(P 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.
(P 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.
(W 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.
(P internal) The reference counts got screwed up on symbol aliases.
(W 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.
(F) You tried to join a thread from within itself, which is an impossible task. You may be joining the wrong thread, or you may need to move the join() to some other thread.
(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.
(W) 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
(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.
(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 *).
(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 '}'.
(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.
(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().
(P) One of the internal hash routines was passed a null HV pointer.
(F) The index looked up in the hash found as the 0'th element of a pseudo-hash is not legal. Index values must be at 1 or greater. See perlref.
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(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";
(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 environment variable PERL_BADFREE
to 1.
(P) An internal request asked to add an array entry to something that wasn't a symbol table entry.
(P) An internal request asked to add a dirhandle entry to something that wasn't a symbol table entry.
(P) An internal request asked to add a filehandle entry to something that wasn't a symbol table entry.
(P) An internal request asked to add a hash entry to something that wasn't a symbol table entry.
(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:
It may also indicate a misspelled constant that has been interpreted as a bareword:
The strict
pragma is useful in avoiding such errors.
(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?
(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?
(F) An untrapped exception was raised while executing a BEGIN subroutine. Compilation stops immediately and the interpreter is exited.
(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.
(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.
(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.
(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.
(W unopened) You tried binmode() on a filehandle that was never opened. Check you control flow and number of arguments.
(W portable) Using bit vector sizes larger than 32 is non-portable.
(P) Perl detected an attempt to copy an internal value that is not copyable.
(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.
(F) A subroutine invoked from an external package via call_sv() exited by calling exit.
(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.
(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 Infinity or a very large number (> 1e308). See pack.
(F) An argument to pack("w",...) was negative. The BER compressed integer format can only be used with positive integers. See pack.
(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.
(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.
(F) Only hard references may be blessed. This is how Perl "enforces" encapsulation of objects. See perlobj.
(F) You called a method correctly, and it correctly indicated a package functioning as a class, but that package doesn't have ANYTHING defined in it, let alone methods. See perlobj.
(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);
(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.
(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);
(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.
(P) For some reason you can't check the filesystem of the script for nosuid.
(F) You used an array where a hash was expected, but the array has no information on how to map from keys to array indices. You can do that only with arrays that have a hash reference at index 0.
(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.
(F) Certain types of SVs, in particular real symbol table entries (typeglobs), can't be forced to stop being what they are.
(F) Certain types of SVs, in particular real symbol table entries (typeglobs), can't be forced to stop being what they are.
(P) An error peculiar to VMS. The process is suffering from exhausted quotas or other plumbing problems.
(F) Currently, only scalar variables can be declared with a specific class qualifier in a "my" or "our" declaration. The semantics may be extended for other types of variables in future.
(F) Only scalar, array, and hash variables may be declared as "my" or "our" variables. They must have ordinary identifiers as names.
(S inplace) You tried to use the -i switch on a special file, such as a file in /dev, or a FIFO. The file was ignored.
(S inplace) The creation of the new file failed for the indicated reason.
(F) You're on a system such as MS-DOS that gets confused if you try
reading from a deleted (but still opened) file. You have to say
-i.bak
, or some such.
(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.
(F) Minima must be less than or equal to maxima. If you really want your regexp to match something 0 times, just put {0}. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(P) The setegid() call failed for some reason in the setuid emulator of suidperl.
(P) The setuid emulator of suidperl failed for some reason.
(F) This typically means that ordinary perl tried to exec suidperl to do setuid emulation, but couldn't exec it. It looks for a name of the form sperl5.000 in the same directory that the perl executable resides under the name perl5.000, typically /usr/local/bin on Unix machines. If the file is there, check the execute permissions. If it isn't, ask your sysadmin why he and/or she removed it.
(F) This machine doesn't have either waitpid() or wait4(), so only waitpid() without flags is emulated.
(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.
(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.)
(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.
(F) You used the -S switch, but the copies of the script to execute found in the PATH did not have correct permissions.
(F) A string of a form CORE::word
was given to prototype(), but there
is no builtin with the name word
.
(F) You used \p{}
or \P{}
but the character property by that name
could not be found. Maybe you misspelled the name of the property
(remember that the names of character properties consist only of
alphanumeric characters), or maybe you forgot the Is
or In
prefix?
(F) You said to goto a label that isn't mentioned anywhere that it's possible for us to go to. See goto.
(F) You used the -S switch, but the script to execute could not be found in the 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.
(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. A good programmer's editor will have a way to help you find these characters.
(F) You may have tried to use \p
which means a Unicode property (for
example \p{Lu}
is all uppercase letters). If you did mean to use a
Unicode property, see perlunicode for the list of known properties.
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, until
possible \E
).
(F) A fatal error occurred while trying to fork while opening a pipeline.
(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.)
(P) An error peculiar to VMS. After creating a mailbox to act as a pipe, Perl can't retrieve its name for later use.
(P) An error peculiar to VMS. Perl asked $GETSYI how big you want your mailbox buffers to be, and didn't get an answer.
(F) A "goto" statement was executed to jump into the middle of a foreach loop. You can't get there from here. See goto.
(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.
(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).
(F) The "goto subroutine" call can't be used to jump out of an eval "string" or block.
(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.
(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.
(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.
(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.
(F) You used local on a variable name that was previously declared as a lexical variable using "my". This is not allowed. If you want to localize a package variable of the same name, qualify it with the package name.
(F) You said something like local $ar->{'key'}
, where $ar is a
reference to a pseudo-hash. That hasn't been implemented yet, but you
can get a similar effect by localizing the corresponding array element
directly -- local $ar->[$ar->[0]{'key'}]
.
(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.
(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 and lib.
(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
.
(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.
(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.
(W syntax) The @ISA array contained the name of another package that doesn't seem to exist.
(F) You tried to use in open() a PerlIO layer that does not exist, e.g. open(FH, ">:nosuchlayer", "somefile").
(F) List assignment to %ENV is not supported on some systems, notably VMS.
(F) You aren't allowed to assign to the item indicated, or otherwise try to change it, such as with an auto-increment.
(P) The internal routine that does assignment to a substr() was handed a NULL.
(F) Subroutines meant to be used in lvalue context should be declared as such, see Lvalue subroutines in perlsub.
(F) The target of a msgrcv must be modifiable to be used as a receive buffer.
(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.
(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.
(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.
(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.
(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.
(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.
(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.
(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.
(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`
.
(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.
(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.
(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.
(S inplace) The rename done by the -i switch failed for some reason, probably because you don't have write permission to the directory.
(P) An error peculiar to VMS. Perl thought stdin was a pipe, and tried to reopen it to accept binary data. Alas, it failed.
(F|P) Error resolving overloading specified by a method name (as opposed
to a subroutine reference): no such method callable via the package. If
method name is ???, this is an internal error.
(P) The setreuid() call failed for some reason in the setuid emulator of suidperl.
(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.
(F) The return statement was executed in mainline code, that is, where there was no subroutine call to return out of. See perlsub.
(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.
(P) For some reason you can't fstat() the script even though you have it open already. Bizarre.
(P) The setreuid() call failed for some reason in the setuid emulator of suidperl.
(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.
(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.
(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.
(F) You tried to unshift an "unreal" array that can't be unshifted, such as the main Perl stack.
(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.
(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::
.
(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.
(F) Only hard references are allowed by "strict refs". Symbolic references are disallowed. See perlref.
(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.
(F) Only a simple scalar variable may be used as a loop variable on a foreach.
(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.
(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.
(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.
(F) Only hard references are allowed by "strict refs". Symbolic references are disallowed. See perlref.
(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.
(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.
(F) You attempted to weaken something that was not a reference. Only references can be weakened.
(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.
(W pack) You said
- pack("C", $x)
where $x is either less than 0 or more than 255; the "C"
format is
only for encoding native operating system characters (ASCII, EBCDIC,
and so on) and not for Unicode characters, so Perl behaved as if you meant
- pack("C", $x & 255)
If you actually want to pack Unicode codepoints, use the "U"
format
instead.
(W pack) You said
- pack("c", $x)
where $x is either less than -128 or more than 127; the "c"
format
is only for encoding native operating system characters (ASCII, EBCDIC,
and so on) and not for Unicode characters, so Perl behaved as if you meant
- pack("c", $x & 255);
If you actually want to pack Unicode codepoints, use the "U"
format
instead.
(W unpack) You tried something like
- unpack("H", "\x{2a1}")
where the format expects to process a byte (a character with a value below 256), but a higher value was provided instead. Perl uses the value modulus 256 instead, as if you had provided:
- unpack("H", "\x{a1}")
(W pack) You tried something like
- pack("u", "\x{1f3}b")
where the format expects to process a sequence of bytes (character with a value below 256), but some of the characters had a higher value. Perl uses the character values modulus 256 instead, as if you had provided:
- pack("u", "\x{f3}b")
(W unpack) You tried something like
- unpack("s", "\x{1f3}b")
where the format expects to process a sequence of bytes (character with a value below 256), but some of the characters had a higher value. Perl uses the character values modulus 256 instead, as if you had provided:
- unpack("s", "\x{f3}b")
(W unopened) You tried to close a filehandle that was never opened.
(W io) The dirhandle you tried to close is either closed or not really a dirhandle. Check your control flow.
(F) You had a (sub-)template that ends with a '/'. There must be another template code following the slash. See pack.
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(F) Perl could not compile a file specified in a require statement.
Perl uses this generic message when none of the errors that it
encountered were severe enough to halt compilation immediately.
(W regexp) The regular expression engine uses recursion in complex
situations where back-tracking is required. Recursion depth is limited
to 32766, or perhaps less in architectures where the stack cannot grow
arbitrarily. ("Simple" and "medium" situations are handled without
recursion and are not subject to a limit.) Try shortening the string
under examination; looping in Perl code (e.g. with while
) rather than
in the regular expression engine; or rewriting the regular expression so
that it is simpler or backtracks less. (See perlfaq2 for information
on Mastering Regular Expressions.)
(W threads) Within a thread-enabled program, you tried to call cond_broadcast() on a variable which wasn't locked. The cond_broadcast() function is used to wake up another thread that is waiting in a cond_wait(). To ensure that the signal isn't sent before the other thread has a chance to enter the wait, it is usual for the signaling thread to first wait for a lock on variable. This lock attempt will only succeed after the other thread has entered cond_wait() and thus relinquished the lock.
(W threads) Within a thread-enabled program, you tried to call cond_signal() on a variable which wasn't locked. The cond_signal() function is used to wake up another thread that is waiting in a cond_wait(). To ensure that the signal isn't sent before the other thread has a chance to enter the wait, it is usual for the signaling thread to first wait for a lock on variable. This lock attempt will only succeed after the other thread has entered cond_wait() and thus relinquished the lock.
(W closed) You tried to do a connect on a closed socket. Did you forget to check the return value of your socket() call? See connect.
(F) The parser found inconsistencies either while attempting to define
an overloaded constant, or when trying to find the character name
specified in the \N{...}
escape. Perhaps you forgot to load the
corresponding overload
or charnames
pragma? See charnames and
overload.
(F) A constant value (perhaps declared using the use constant
pragma)
is being dereferenced, but it amounts to the wrong type of reference.
The message indicates the type of reference that was expected. This
usually indicates a syntax error in dereferencing the constant value.
See Constant Functions in perlsub and constant.
(S) You redefined a subroutine which had previously been eligible for inlining. See Constant Functions in perlsub for commentary and workarounds.
(W misc) You undefined a subroutine which had previously been eligible for inlining. See Constant Functions in perlsub for commentary and workarounds.
(F) The method which overloads "=" is buggy. See Copy Constructor in overload.
(F) The CORE:: namespace is reserved for Perl keywords.
(P) The regular expression engine got confused by what the regular expression compiler gave it.
(P) The regular expression engine got passed a regexp program without a valid magic number.
(P) The malloc package that comes with Perl had an internal failure.
(F) You had an unpack template indicating a counted-length string, but you have also specified an explicit size for the string. See pack.
(W recursion) This subroutine has called itself (directly or indirectly) 100 times more than it has returned. This probably indicates an infinite recursion, unless you're writing strange benchmark programs, in which case it indicates something else.
(D deprecated) defined() is not usually 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.
(D deprecated) defined() is not usually useful on hashes because it
checks for an undefined scalar value. If you want to see if the hash
is empty, just use if (%hash) { # not empty } for example.
(F) You said something like "use Module 42" but in the Module file
there are neither package declarations nor a $VERSION
.
(F) In a here document construct like <<FOO, the label FOO
is too
long for Perl to handle. You have to be seriously twisted to write code
that triggers this error.
(F) A DESTROY() method created a new reference to the object which is just being DESTROYed. Perl is confused, and prefers to abort rather than to create a dangling reference.
See Server error.
(F) A required (or used) file must return a true value to indicate that it compiled correctly and ran its initialization code correctly. It's traditional to end such a file with a "1;", though any true value would do. See require.
(W) You probably referred to an imported subroutine &FOO as $FOO or some such.
(W misc) Remember that "our" does not localize the declared global variable. You have declared it again in the same lexical scope, which seems superfluous.
(W) You probably said %hash{$key} when you meant $hash{$key} or @hash{@keys}. On the other hand, maybe you just meant %hash and got carried away.
(F) You passed die() an empty string (the equivalent of die ""
) or
you called it with no args and both $@
and $_
were empty.
See Server error.
(F) You said something like "use Module 42" but the Module did not
define a $VERSION.
(F) You cannot put a repeat count of any kind right after the '/' code. See pack.
(P) The internal handling of magical variables has been cursed.
(P) This should have been caught by safemalloc() instead.
(S syntax) This is an educated guess made in conjunction with the message "%s found where operator expected". It often means a subroutine or module name is being referenced that hasn't been declared yet. This may be because of ordering problems in your file, or because of a missing "sub", "package", "require", or "use" statement. If you're referencing something that isn't defined yet, you don't actually have to define the subroutine or package before the current location. You can use an empty "sub foo;" or "package FOO;" to enter a "forward" declaration.
(W misc) You used the obsolescent dump() built-in function, without fully
qualifying it as CORE::dump()
. Maybe it's a typo. See dump.
(F) Your machine doesn't support dump/undump.
(S malloc) An internal routine called free() on something that had already been freed.
(W) You have applied the same modifier more than once after a type in a pack template. See pack.
(S syntax) There is no keyword "elseif" in Perl because Larry thinks it's ugly. Your code will be interpreted as an attempt to call a method named "elseif" for the class returned by the following block. This is unlikely to be what you want.
(F) \p
and \P
are used to introduce a named Unicode property, as
described in perlunicode and perlre. You used \p
or \P
in
a regular expression without specifying the property name.
(F) While under the use filetest
pragma, switching the real and
effective uids or gids failed.
(F) You're running under taint mode, and the %ENV
variable has been
aliased to another hash, so it doesn't reflect anymore the state of the
program's environment. This is potentially insecure.
(F) An error peculiar to VMS. Because Perl may have to deal with file specifications in either VMS or Unix syntax, it converts them to a single form when it must operate on them directly. Either you've passed an invalid file specification to Perl, or you've found a case the conversion routines don't handle. Drat.
(F) Perl detected tainted data when trying to compile a regular
expression that contains the (?{ ... }) zero-width assertion, which
is unsafe. See (?{ code }) in perlre, and perlsec.
(F) Perl tried to compile a regular expression containing the
(?{ ... }) zero-width assertion at run time, as it would when the
pattern contains interpolated values. Since that is a security risk, it
is not allowed. If you insist, you may still do this by explicitly
building the pattern from an interpolated string at run time and using
that in an eval(). See (?{ code }) in perlre.
(F) A regular expression contained the (?{ ... }) zero-width
assertion, but that construct is only allowed when the use re 'eval'
pragma is in effect. See (?{ code }) in perlre.
(F) The contents of a <> operator may not exceed the maximum size of a Perl identifier. If you're just trying to glob a long list of filenames, try using the glob() operator, or put the filenames into a variable and glob that.
(F) The exec function is not implemented in MacPerl. See perlport.
(F) The final summary message when a Perl compilation fails.
(W exiting) You are exiting an eval by unconventional means, such as a goto, or a loop control statement.
(W exiting) You are exiting a format by unconventional means, such as a goto, or a loop control statement.
(W exiting) You are exiting a rather special block construct (like a sort block or subroutine) by unconventional means, such as a goto, or a loop control statement. See sort.
(W exiting) You are exiting a subroutine by unconventional means, such as a goto, or a loop control statement.
(W exiting) You are exiting a substitution by unconventional means, such as a return, a goto, or a loop control statement.
(W misc) You are blessing a reference to a zero length string. This has the effect of blessing the reference into the package main. This is usually not what you want. Consider providing a default target package, e.g. bless($ref, $p || 'MyPackage');
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(F) An untrapped exception was raised while executing a CHECK, INIT, or END subroutine. Processing of the remainder of the queue of such routines has been prematurely ended.
(W regexp) A character class range must start and end at a literal
character, not another character class like \d
or [:alpha:]. The "-"
in your false range is interpreted as a literal "-". Consider quoting the
"-", "\-". The <-- HERE shows in the regular expression about where the
problem was discovered. See perlre.
(P) An error peculiar to VMS. Something untoward happened in a VMS system service or RTL routine; Perl's exit status should provide more details. The filename in "at %s" and the line number in "line %d" tell you which section of the Perl source code is distressed.
(F) Your machine apparently doesn't implement fcntl(). What is this, a PDP-11 or something?
(F) A tied array claimed to have a negative number of elements, which is not possible.
(W pack) Each line in an uuencoded string start with a length indicator
which can't encode values above 63. So there is no point in asking for
a line length bigger than that. Perl will behave as if you specified
u63
as format.
(W io) You tried to write on a read-only filehandle. If you intended it to be a read-write filehandle, you needed to open it with "+<" or "+>" or "+>>" instead of with "<" or nothing. If you intended only to write the file, use ">" or ">>". See open.
(W io) You tried to read from a filehandle opened only for writing, If you intended it to be a read/write filehandle, you needed to open it with "+<" or "+>" or "+>>" instead of with "<" or nothing. If you intended only to read from the file, use "<". See open. Another possibility is that you attempted to open filedescriptor 0 (also known as STDIN) for output (maybe you closed STDIN earlier?).
(W io) You opened for reading a filehandle that got the same filehandle id as STDOUT or STDERR. This occurred because you closed STDOUT or STDERR previously.
(W io) You opened for writing a filehandle that got the same filehandle id as STDIN. This occurred because you closed STDIN previously.
(F) You must now decide whether the final $ in a string was meant to be a literal dollar sign, or was meant to introduce a variable name that happens to be missing. So you have to put either the backslash or the name.
(W closed) The filehandle you're attempting to flock() got itself closed some time before now. Check your control flow. flock() operates on filehandles. Are you attempting to call flock() on a dirhandle by the same name?
(F) A format must be terminated by a line with a solitary dot. Perl got to the end of your file without finding such a line.
(W redefine) You redefined a format. To suppress this warning, say
(W syntax) You said
- if ($foo = 123)
when you meant
- if ($foo == 123)
(or something like that).
(S syntax) The Perl lexer knows whether to expect a term or an operator. If it sees what it knows to be a term when it was expecting to see an operator, it gives you this warning. Usually it indicates that an operator or delimiter was omitted, such as a semicolon.
(S) A warning from the GDBM_File extension that a store failed.
(F) Your C library apparently doesn't implement gethostent(), probably because if it did, it'd feel morally obligated to return every hostname on the Internet.
(W closed) You tried to get a socket or peer socket name on a closed socket. Did you forget to check the return value of your socket() call?
(S) A warning peculiar to VMS. The call to sys$getuai
underlying the
getpwnam operator returned an invalid UIC.
(W closed) You tried to get a socket option on a closed socket. Did you forget to check the return value of your socket() call? See getsockopt.
(F) You've said "use strict" or "use strict vars", which indicates that all variables must either be lexically scoped (using "my"), declared beforehand using "our", or explicitly qualified to say which package the global variable is in (using "::").
(W glob) Something went wrong with the external program(s) used for
glob and <*.c>
. Usually, this means that you supplied a
glob pattern that caused the external program to fail and exit with a
nonzero status. If the message indicates that the abnormal exit
resulted in a coredump, this may also mean that your csh (C shell) is
broken. If so, you should change all of the csh-related variables in
config.sh: If you have tcsh, make the variables refer to it as if it
were csh (e.g. full_csh='/usr/bin/tcsh'
); otherwise, make them all
empty (except that d_csh
should be 'undef'
) so that Perl will
think csh is missing. In either case, after editing config.sh, run
./Configure -S and rebuild Perl.
(F) The lexer saw a left angle bracket in a place where it was expecting a term, so it's looking for the corresponding right angle bracket, and not finding it. Chances are you left some needed parentheses out earlier in the line, and you really meant a "less than".
(P) An error peculiar to OS/2. Most probably you're using an obsolete version of Perl, and this should not happen anyway.
(F) Unlike with "next" or "last", you're not allowed to goto an unspecified destination. See goto.
(F) A ()-group started with a count. A count is supposed to follow something: a template character or a ()-group. See pack.
(F) The final summary message when a perl -c
fails.
(S internal) A routine asked for a symbol from a symbol table that ought to have existed already, but for some reason it didn't, and had to be created on an emergency basis to prevent a core dump.
(D deprecated) Really old Perl let you omit the % on hash names in some spots. This is now heavily deprecated.
(F) The parser has given up trying to parse the program after 10 errors. Further error messages would likely be uninformative.
(W portable) The hexadecimal number you specified is larger than 2**32-1 (4294967295) and therefore non-portable between systems. See perlport for more on portability concerns.
(F) Perl limits identifiers (names for variables, functions, etc.) to
about 250 characters for simple names, and somewhat more for compound
names (like $A::B
). You've exceeded Perl's limits. Future versions
of Perl are likely to eliminate these arbitrary limitations.
(F) You used a digit other than 0 or 1 in a binary number.
(W digit) You may have tried to use a digit other than 0 or 1 in a binary number. Interpretation of the binary number stopped before the offending digit.
(F) Perl normally treats carriage returns in the program text as it would any other whitespace, which means you should never see this error when Perl was built using standard options. For some reason, your version of Perl appears to have been built without this support. Talk to your Perl administrator.
(W syntax) An illegal character was found in a prototype declaration. Legal characters in prototypes are $, @, %, *, ;, [, ], &, and \.
(F) When using the sub keyword to construct an anonymous subroutine,
you must always specify a block of code. See perlsub.
(F) A subroutine was not declared correctly. See perlsub.
(F) You tried to divide a number by 0. Either something was wrong in your logic, or you need to put a conditional in to guard against meaningless input.
(W digit) You may have tried to use a character other than 0 - 9 or A - F, a - f in a hexadecimal number. Interpretation of the hexadecimal number stopped before the illegal character.
(F) You tried to divide a number by 0 to get the remainder. Most numbers don't take to this kindly.
(F) The number of bits in vec() (the third argument) must be a power of two from 1 to 32 (or 64, if your platform supports that).
(F) You used an 8 or 9 in an octal number.
(W digit) You may have tried to use an 8 or 9 in an octal number. Interpretation of the octal number stopped before the 8 or 9.
(X) The PERL5OPT environment variable may only be used to set the following switches: -[CDIMUdmtw].
(W internal) A warning peculiar to VMS. Perl tried to read the CRTL's
internal environ array, and encountered an element without the =
delimiter used to separate keys from values. The element is ignored.
(W internal) A warning peculiar to VMS. Perl tried to read a logical name or CLI symbol definition when preparing to iterate over %ENV, and didn't see the expected delimiter between key and value, so the line was ignored.
(W misc) This prefix usually indicates that a DESTROY() method raised the indicated exception. Since destructors are usually called by the system at arbitrary points during execution, and often a vast number of times, the warning is issued only once for any number of failures that would otherwise result in the same message being repeated.
Failure of user callbacks dispatched using the G_KEEPERR
flag could
also result in this warning. See G_KEEPERR in perlcall.
(F) An error peculiar to EBCDIC. Internally, v-strings are stored as Unicode code points, and encoded in EBCDIC as UTF-EBCDIC. The UTF-EBCDIC encoding is limited to code points no larger than 2147483647 (0x7FFFFFFF).
(F) You tried to do something that the tainting mechanism didn't like. The tainting mechanism is turned on when you're running setuid or setgid, or when you specify -T to turn it on explicitly. The tainting mechanism labels all data that's derived directly or indirectly from the user, who is considered to be unworthy of your trust. If any such data is used in a "dangerous" operation, you get this error. See perlsec for more information.
(F) You can't use system(), exec(), or a piped open in a setuid or
setgid script if $ENV{PATH}
contains a directory that is writable by
the world. Also, the PATH must not contain any relative directory.
See perlsec.
(F) You can't use system(), exec(), or a piped open in a setuid or
setgid script if any of $ENV{PATH}
, $ENV{IFS}
, $ENV{CDPATH}
,
$ENV{ENV}
, $ENV{BASH_ENV}
or $ENV{TERM}
are derived from data
supplied (or potentially supplied) by the user. The script must set
the path to a known value, using trustworthy data. See perlsec.
(W overflow) The hexadecimal, octal or binary number you have specified either as a literal or as an argument to hex() or oct() is too big for your architecture, and has been converted to a floating point number. On a 32-bit architecture the largest hexadecimal, octal or binary number representable without overflow is 0xFFFFFFFF, 037777777777, or 0b11111111111111111111111111111111 respectively. Note that Perl transparently promotes all numbers to a floating point representation internally--subject to loss of precision errors in subsequent operations.
(F) The indexes and widths specified in the format string of printf()
or sprintf() are too large. The numbers must not overflow the size of
integers for your architecture.
(P) Something went badly wrong in the regular expression parser. The <-- HERE shows in the regular expression about where the problem was discovered.
(S) A warning peculiar to VMS. Perl keeps track of the number of times
you've called fork and exec, to determine whether the current call
to exec should affect the current script or a subprocess (see
exec LIST in perlvms). Somehow, this count has become scrambled, so
Perl is making a guess and treating this exec as a request to
terminate the Perl script and execute the specified command.
(P) Something went badly awry in the regular expression parser. The <-- HERE shows in the regular expression about where the problem was discovered.
(W syntax) You've run afoul of the rule that says that any list operator followed by parentheses turns into a function, with all the list operators arguments found inside the parentheses. See Terms and List Operators (Leftward) in perlop.
The indicated attribute for a subroutine or variable was not recognized by Perl or by a user-supplied handler. See attributes.
The indicated attributes for a subroutine or variable were not recognized by Perl or by a user-supplied handler. See attributes.
(W printf) Perl does not understand the given format conversion. See sprintf.
(W regexp) The numeric escape (for example \xHH
) of value < 256
didn't correspond to a single character through the conversion
from the encoding specified by the encoding pragma.
The escape was replaced with REPLACEMENT CHARACTER (U+FFFD) instead.
The <-- HERE shows in the regular expression about where the
escape was discovered.
(F) The range specified in a character class had a minimum character
greater than the maximum character. One possibility is that you forgot the
{}
from your ending \x{}
- \x
without the curly braces can go only
up to ff
. The <-- HERE shows in the regular expression about where the
problem was discovered. See perlre.
(F) The range specified in the tr/// or y/// operator had a minimum character greater than the maximum character. See perlop.
(F) Something other than a colon or whitespace was seen between the elements of an attribute list. If the previous attribute had a parenthesised parameter list, perhaps that list was terminated too soon. See attributes.
(W layer) When pushing layers onto the Perl I/O system, something other than a colon or whitespace was seen between the elements of a layer list. If the previous attribute had a parenthesised parameter list, perhaps that list was terminated too soon.
(F) The given character is not a valid pack or unpack type. See pack. (W) The given character is not a valid pack or unpack type but used to be silently ignored.
(F) Your machine apparently doesn't implement ioctl(), which is pretty strange for a machine that supports C.
(W unopened) You tried ioctl() on a filehandle that was never opened. Check you control flow and number of arguments.
(F) Your Perl has not been configured to have PerlIO, and therefore you cannot use IO layers. To have PerlIO Perl must be configured with 'useperlio'.
(F) Your machine doesn't implement the sockatmark() functionality, neither as a system call or an ioctl call (SIOCATMARK).
(W overload) The second (fourth, sixth, ...) argument of overload::constant needs to be a code reference. Either an anonymous subroutine, or a reference to a subroutine.
(W overload) You tried to overload a constant type the overload package is unaware of.
(P) The regular expression parser is confused.
(F) You named a loop to break out of, but you're not currently in a loop of that name, not even if you count where you were called from. See last.
(F) You named a loop to continue, but you're not currently in a loop of that name, not even if you count where you were called from. See last.
(F) You named a loop to restart, but you're not currently in a loop of that name, not even if you count where you were called from. See last.
(F) While under the use filetest
pragma, switching the real and
effective uids or gids failed.
(F) While unpacking, the string buffer was already used up when an unpack length/code combination tried to obtain more data. This results in an undefined value for the length. See pack.
(W closed) You tried to do a listen on a closed socket. Did you forget to check the return value of your socket() call? See listen.
(F) There is currently a limit on the length of string which lookbehind can handle. This restriction may be eased in a future release. The <-- HERE shows in the regular expression about where the problem was discovered.
(W io) You tried to do an lstat on a filehandle. What did you mean by that? lstat() makes sense only on filenames. (Perl did a fstat() instead on the filehandle.)
(F) Due to limitations in the current implementation, array and hash values cannot be returned in subroutines used in lvalue context. See Lvalue subroutines in perlsub.
(F) Between the brackets enclosing a numeric repeat count only digits are permitted. See pack.
(F) Between the brackets enclosing a numeric repeat count only digits are permitted. See pack.
(F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form
- prefix1;prefix2
or prefix1 prefix2
with nonempty prefix1 and prefix2. If prefix1
is indeed a prefix of
a builtin library search path, prefix2 is substituted. The error may
appear if components are not found, or are too long. See
"PERLLIB_PREFIX" in perlos2.
(F) You tried to use a function with a malformed prototype. The syntax of function prototypes is given a brief compile-time check for obvious errors like invalid characters. A more rigorous check is run when the function is called.
(S utf8) (F) Perl detected a string that didn't comply with UTF-8 encoding rules, even though it had the UTF8 flag on.
One possible cause is that you set the UTF8 flag yourself for data that you thought to be in UTF-8 but it wasn't (it was for example legacy 8-bit data). To guard against this, you can use Encode::decode_utf8.
If you use the :encoding(UTF-8)
PerlIO layer for input, invalid byte
sequences are handled gracefully, but if you use :utf8
, the flag is
set without validating the data, possibly resulting in this error
message.
See also Handling Malformed Data in Encode.
Perl thought it was reading UTF-16 encoded character data but while doing it Perl met a malformed Unicode surrogate.
(F) You tried to pack something that didn't comply with UTF-8 encoding rules and perl was unable to guess how to make more progress.
(F) You tried to unpack something that didn't comply with UTF-8 encoding rules and perl was unable to guess how to make more progress.
(F) You tried to unpack something that didn't comply with UTF-8 encoding rules and perl was unable to guess how to make more progress.
(F) Perl aborted due to a too important number of signals pending. This usually indicates that your operating system tried to deliver signals too fast (with a very high priority), starving the perl process from resources it would need to reach a point where it can process signals safely. (See Deferred Signals (Safe Signals) in perlipc.)
(W regexp) The pattern you've specified would be an infinite loop if the regular expression engine didn't specifically check for that. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(W) This warning may be due to running a perl5 script through a perl4 interpreter, especially if the word that is being warned about is "use" or "my".
(F) You can't pack a string by supplying a checksum, because the checksumming process loses information, and you can't go the other way. See unpack.
(F) An attempt was made to specify an entry in an overloading table that doesn't resolve to a valid subroutine. See overload.
See Server error.
(S) An advisory indicating that the previous error may have been caused by a missing delimiter on a string or pattern, because it eventually ended earlier on the current line.
(W syntax) An underscore (underbar) in a numeric constant did not separate two digits.
(F) The argument to the indicated command line switch must follow immediately after the switch, without intervening spaces.
(F) Wrong syntax of character name literal \N{charname}
within
double-quotish context.
(F) While certain functions allow you to specify a filehandle or an "indirect object" before the argument list, this ain't one of them.
(W pipe) You used the open(FH, "| command")
or
open(FH, "command |")
construction, but the command was missing or
blank.
(F) A double-quoted string ended with "\c", without the required control character name.
(F) The reserved syntax for lexically scoped subroutines requires that they have a name with which they can be found.
(F) Apparently you've been programming in csh too much. Variables are always mentioned with the $ in Perl, unlike in the shells, where it can vary from one line to the next.
(S syntax) This is an educated guess made in conjunction with the message "%s found where operator expected". Often the missing operator is a comma.
(F) Missing right brace in \p{...}
or \P{...}
.
(F) The lexer counted more opening curly or square brackets than closing ones. As a general rule, you'll find it's missing near the place you were last editing.
(S syntax) This is an educated guess made in conjunction with the message "%s found where operator expected". Don't automatically put a semicolon on the previous line just because you saw this message.
(F) You tried, directly or indirectly, to change the value of a constant. You didn't, of course, try "2 = 1", because the compiler catches that. But an easy way to do the same thing is:
Another way is to assign to a substr() that's off the end of the string.
Yet another way is to assign to a foreach
loop VAR when VAR
is aliased to a constant in the look LIST:
- $x = 1;
- foreach my $n ($x, 2) {
- $n *= 2; # modifies the $x, but fails on attempt to modify the 2
- }
(F) You tried to make an array value spring into existence, and the subscript was probably negative, even counting from end of the array backwards.
(P) You tried to make a hash value spring into existence, and it couldn't be created for some peculiar reason.
(F) Only a bare module name is allowed as the first argument to a "use".
(F) The -M
or -m options say that Perl should load some module, but
you omitted the name of the module. Consult perlrun for full details
about -M
and -m.
(F) The open function has been asked to open multiple files. This
can happen if you are trying to open a pipe to a command that takes a
list of arguments, but have forgotten to specify a piped open mode.
See open for details.
(F) You don't have System V message IPC on your system.
(W syntax) Multidimensional arrays aren't written like $foo[1,2,3]
.
They're written like $foo[1][2][3]
, as in C.
(F) You had an unpack template that contained a '/', but this did not follow some unpack specification producing a numeric value. See pack.
(F) Lexically scoped subroutines are not yet implemented. Don't try that yet.
(F) Lexically scoped variables aren't in a package, so it doesn't make sense to try to declare one with a package qualifier on the front. Use local() if you want to localize a package variable.
(W once) Typographical errors often show up as unique variable names.
If you had a good reason for having a unique name, then just mention it
again somehow to suppress the message. The our declaration is
provided for this purpose.
NOTE: This warning detects symbols that have been used only once so $c, @c, %c, *c, &c, sub c{}, c(), and c (the filehandle or format) are considered the same; if a program uses $c only once but also uses any of the others it will not trigger this warning.
(F) The length count obtained from a length/code unpack operation was negative. See pack.
(F) You tried to do a read/write/send/recv operation with a buffer length that is less than 0. This is difficult to imagine.
(F) When vec is called in an lvalue context, the second argument must be
greater than or equal to zero.
(F) You can't quantify a quantifier without intervening parentheses. So things like ** or +* or ?* are illegal. The <-- HERE shows in the regular expression about where the problem was discovered.
Note that the minimal matching quantifiers, *?
, +?, and
??
appear to be nested quantifiers, but aren't. See perlre.
(S internal) The symbol in question was declared but somehow went out of scope before it could possibly have been used.
(W printf) There is a newline in a string to be left justified by
printf or sprintf.
The padding spaces will appear after the newline, which is probably not
what you wanted. Usually you should remove the newline from the string
and put formatting characters in the sprintf format.
(F) Certain operations are deemed to be too insecure for a setuid or setgid script to even be allowed to attempt. Generally speaking there will be another way to do what you want that is, if not secure, at least securable. See perlsec.
(F) A list operator that has a filehandle or "indirect object" is not allowed to have a comma between that and the following arguments. Otherwise it'd be just another one of the arguments.
One possible cause for this is that you expected to have imported a constant to your name space with use or import while no such importing took place, it may for example be that your operating system does not support that particular constant. Hopefully you did use an explicit import list for the constants you expect to see, please see use and import. While an explicit import list would probably have caught this error earlier it naturally does not remedy the fact that your operating system still does not support that constant. Maybe you have a typo in the constants of the symbol import list of use or import or in the constant name at the line where this error was triggered?
(F) An error peculiar to VMS. Perl handles its own command line redirection, and found a '|' at the end of the command line, so it doesn't know where you want to pipe the output from this command.
(F) The currently executing code was compiled with the -d switch, but
for some reason the current debugger (e.g. perl5db.pl or a Devel::
module) didn't define a routine to be called at the beginning of each
statement.
(P) This is counted as an internal error, because every machine should supply dbm nowadays, because Perl comes with SDBM. See SDBM_File.
(F) The currently executing code was compiled with the -d switch, but
for some reason the current debugger (e.g. perl5db.pl or a Devel::
module) didn't define a DB::sub
routine to be called at the beginning
of each ordinary subroutine call.
(F) A setuid script can't be specified by the user.
(F) An error peculiar to VMS. Perl handles its own command line redirection, and found a '2>' or a '2>>' on the command line, but can't find the name of the file to which to write data destined for stderr.
(F) A pack or unpack template has an opening '(' or '[' without its matching counterpart. See pack.
(F) An error peculiar to VMS. Perl handles its own command line redirection, and found a '<' on the command line, but can't find the name of the file from which to read data for stdin.
(F) The setuid emulator requires that scripts have a well-formed #! line even on machines that don't support the #! construct.
(F) The "no" keyword is recognized and executed at compile time, and returns no useful value. See perlmod.
(F) An error peculiar to VMS. Perl handles its own command line redirection, and found a lone '>' at the end of the command line, so it doesn't know where you wanted to redirect stdout.
(F) An error peculiar to VMS. Perl handles its own command line redirection, and found a '>' or a '>>' on the command line, but can't find the name of the file to which to write data destined for stdout.
(F) Fully qualified variable names are not allowed in "our" declarations, because that doesn't make much sense under existing semantics. Such syntax is reserved for future extensions.
(F) You called perl -x
, but no line was found in the file beginning
with #! and containing the word "perl".
(F) Configure didn't find anything resembling the setregid() call for your system.
(F) Configure didn't find anything resembling the setreuid() call for your system.
(F) The indicated command line switch needs a mandatory argument, but you haven't specified one.
(F) You provided a class qualifier in a "my" or "our" declaration, but this class doesn't exist at this point in your program.
(F) You specified a signal hook that was not recognized by Perl. Currently, Perl
accepts __DIE__
and __WARN__
as valid signal hooks
(P) An error peculiar to VMS. The internal routine my_pclose() tried to close a pipe which hadn't been opened. This should have been caught earlier as an attempt to close an unopened filehandle.
(F) You tried to access an array as a hash, but the field name used is not defined. The hash at index 0 should map all valid field names to array indices for that to work.
(F) You tried to access a field of a typed variable where the type does not know about the field name. The field names are looked up in the %FIELDS hash in the type package at compile time. The %FIELDS hash is %usually set up with the 'fields' pragma.
(W signal) You specified a signal name as a subscript to %SIG that was
not recognized. Say kill -l
in your shell to see the valid signal
names on your system.
(F) Perl was trying to evaluate a reference to a code value (that is, a subroutine), but found a reference to something else instead. You can use the ref() function to find out what kind of ref it really was. See also perlref.
(F) I'm not sure how you managed to generate a reference to an anonymous format, but this indicates you did, and that it didn't exist.
(F) Perl was trying to evaluate a reference to a "typeglob" (that is, a
symbol table entry that looks like *foo
), but found a reference to
something else instead. You can use the ref() function to find out what
kind of ref it really was. See perlref.
(F) Perl was trying to evaluate a reference to a hash value, but found a reference to something else instead. You can use the ref() function to find out what kind of ref it really was. See perlref.
(F) Perl was trying to evaluate a reference to an array value, but found a reference to something else instead. You can use the ref() function to find out what kind of ref it really was. See perlref.
(F) The setuid emulator requires that scripts have a well-formed #! line even on machines that don't support the #! construct. The line must mention perl.
(F) Perl was trying to evaluate a reference to a scalar value, but found a reference to something else instead. You can use the ref() function to find out what kind of ref it really was. See perlref.
(F) Perl was trying to evaluate a reference to a code value (that is, a subroutine), but found a reference to something else instead. You can use the ref() function to find out what kind of ref it really was. See also perlref.
(F) An attempt was made to specify an entry in an overloading table that doesn't somehow point to a valid subroutine. See overload.
(F) The function requires more arguments than you specified.
(W syntax) A format specified more picture fields than the next line supplied. See perlform.
(A) You've accidentally run your script through the Bourne shell instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(S) A warning peculiar to VMS. Perl was unable to find the local timezone offset, so it's assuming that local system time is equivalent to UTC. If it's not, define the logical name SYS$TIMEZONE_DIFFERENTIAL to translate to the number of seconds which need to be added to UTC to get local time.
(W misc) A number has been passed as a bitmask argument to select(). Use the vec() function to construct the file descriptor bitmasks for select. See select
(F) You can't require the null filename, especially because on many machines that means the current directory! See require.
(P debugging) Some internal routine called run() with a null opcode pointer.
(F) The first argument to formline must be a valid format picture specification. It was found to be empty, which probably means you supplied it an uninitialized value. See perlform.
(P) An attempt was made to realloc NULL.
(P) The internal pattern matching routines blew it big time.
(P) The internal pattern matching routines are out of their gourd.
(F) Perl limits the representation of decimal numbers in programs to about 250 characters. You've exceeded that length. Future versions of Perl are likely to eliminate this arbitrary limitation. In the meantime, try using scientific notation (e.g. "1e6" instead of "1_000_000").
(F) Numbers with a leading 0
are not currently allowed in vectors.
The octal number interpretation of such numbers may be supported in a
future version.
(W portable) The octal number you specified is larger than 2**32-1 (4294967295) and therefore non-portable between systems. See perlport for more on portability concerns.
See also perlport for writing portable code.
(W overload) The call to overload::constant contained an odd number of arguments. The arguments should come in pairs.
(W misc) You specified an odd number of elements to initialize a hash, which is odd, because hashes come in key/value pairs.
(W misc) You specified an odd number of elements to initialize a hash, which is odd, because hashes come in key/value pairs.
(F, W layer) You tried to do a read/write/send/recv/seek operation
with an offset pointing outside the buffer. This is difficult to
imagine. The sole exceptions to this are that zero padding will
take place when going past the end of the string when either
sysread()ing a file, or when seeking past the end of a scalar opened
for I/O (in anticipation of future reads and to imitate the behaviour
with real files).
(W unopened) An I/O operation was attempted on a filehandle that was never initialized. You need to do an open(), a sysopen(), or a socket() call, or call a constructor from the FileHandle package.
(W unopened) You tried to invoke a file test operator on a filehandle that isn't open. Check your control flow. See also -X.
(S internal) An internal warning that the grammar is screwed up.
(S internal) An internal warning that the grammar is screwed up.
(F) An attempt was made to perform an overloaded operation for which no
handler was defined. While some handlers can be autogenerated in terms
of other handlers, there is no default handler for any operation, unless
fallback
overloading key is specified to be true. See overload.
(S ambiguous) You used a variable or subroutine call where the parser was expecting an operator. The parser has assumed you really meant to use an operator, but this is highly likely to be incorrect. For example, if you say "*foo *foo" it will be interpreted as if you said "*foo * 'foo'".
(W misc) You seem to have already declared the same global once before in the current lexical scope.
(X) The malloc() function returned 0, indicating there was insufficient remaining memory (or virtual memory) to satisfy the request. Perl has no option but to exit immediately.
At least in Unix you may be able to get past this by increasing your
process datasize limits: in csh/tcsh use limit
and
limit datasize n
(where n
is the number of kilobytes) to check
the current limits and change them, and in ksh/bash/zsh use ulimit -a
and ulimit -d n
, respectively.
(X) An attempt was made to extend an array, a list, or a string beyond the largest possible memory allocation.
(F) The malloc() function returned 0, indicating there was insufficient remaining memory (or virtual memory) to satisfy the request. However, the request was judged large enough (compile-time default is 64K), so a possibility to shut down by trapping this error is granted.
(X|F) The malloc() function returned 0, indicating there was insufficient remaining memory (or virtual memory) to satisfy the request.
The request was judged to be small, so the possibility to trap it
depends on the way perl was compiled. By default it is not trappable.
However, if compiled for this, Perl may use the contents of $^M
as an
emergency pool after die()ing with this message. In this case the error
is trappable once, and the error message will include the line and file
where the failed request happened.
(F) You can't allocate more than 2^31+"small amount" bytes. This error
is most likely to be caused by a typo in the Perl program. e.g.,
$arr[time]
instead of $arr[$time]
.
(F) The yacc parser wanted to grow its stack so it could continue parsing, but realloc() wouldn't give it more memory, virtual or otherwise.
(F) You had a template that specified an absolute position outside the string being unpacked. See pack.
(F) You had a template that specified an absolute position outside the string being unpacked. The string being unpacked was also invalid UTF-8. See pack.
(W reserved) A lowercase attribute name was used that had a package-specific handler. That name might have a meaning to Perl itself some day, even though it doesn't yet. Perhaps you should use a mixed-case attribute name, instead. See attributes.
(F) You can't specify a repeat count so large that it overflows your signed integers. See pack.
(W io) A single call to write() produced more lines than can fit on a page. See perlform.
(P) An internal error.
(P) One of the file test operators entered a code branch that calls an ACL related-function, but that function is not available on this platform. Earlier checks mean that it should not be possible to enter this branch on this platform.
(P) Failed an internal consistency check trying to compile a grep.
(P) Failed an internal consistency check trying to compile a split.
(P) The savestack was requested to restore more localized values than there are in the savestack.
(P) Failed an internal consistency check while trying to reset a weak reference.
(P) Devel::DProf called a subroutine that exited using goto(LABEL), last(LABEL) or next(LABEL). Leaving that way a subroutine called from an XSUB will lead very probably to a crash of the interpreter. This is a bug that will hopefully one day get fixed.
(P) We popped the context stack to an eval context, and then discovered it wasn't an eval context.
(P) The internal pp_subst() routine was called with invalid operational data.
(P) The internal do_trans routines were called with invalid operational data.
(P) While attemtping folding constants an exception other than an eval
failure was caught.
(P) The library function frexp() failed, making printf("%f") impossible.
(P) We popped the context stack to a context with the specified label, and then discovered it wasn't a context we know how to do a goto in.
(P) The lexer got into a bad state at a case modifier.
(P) The lexer got into a bad state parsing a string with brackets.
(F) forked child returned an incomprehensible message about its errno.
(P) We popped the context stack to a block context, and then discovered it wasn't a block context.
(P) A writable lexical variable became read-only somehow within the scope.
(P) The savestack probably got out of sync. At least, there was an invalid enum on the top of it.
(P) Failed an internal consistency check while trying to reset all weak references to an object.
(P) Something requested a negative number of bytes of malloc.
(P) Something tried to allocate more memory than possible.
(P) One of the internal array routines was passed a null AV pointer.
(P) The compiler got confused about which scratch pad it was allocating and freeing temporaries and lexicals from.
(P) The compiler got confused about which scratch pad it was allocating and freeing temporaries and lexicals from.
(P) An invalid scratch pad offset was detected internally.
(P) The compiler got confused about which scratch pad it was allocating and freeing temporaries and lexicals from.
(P) An invalid scratch pad offset was detected internally.
(P) The compiler got confused about which scratch pad it was allocating and freeing temporaries and lexicals from.
(P) An invalid scratch pad offset was detected internally.
(P) The foreach iterator got called in a non-loop context frame.
(P) The internal pp_match() routine was called with invalid operational data.
(P) Something terrible went wrong in setting up for the split.
(P) Something requested a negative number of bytes of realloc.
(P) Some internal routine requested a goto (or something like it), and didn't supply the destination.
(P) We popped the context stack to a subroutine or eval context, and then discovered it wasn't a subroutine or eval context.
(P) scan_num() got called on something that wasn't a number.
(P) The sv_chop() routine was passed a position that is not within the scalar's string buffer.
(P) The sv_insert() routine was told to remove more string than there was string.
(P) The compiler attempted to do a goto, or something weird like that.
(P) The compiler is screwed up and attempted to use an op that isn't permitted at run time.
(P) Something tried to call utf16_to_utf8 with an odd (as opposed to even) byte length.
(P) The lexer got into a bad state while processing a case modifier.
(W parenthesis) You said something like
- my $foo, $bar = @_;
when you meant
- my ($foo, $bar) = @_;
Remember that "my", "our", and "local" bind tighter than comma.
-p
destination: %s
(F) An error occurred during the implicit output invoked by the -p
command-line switch. (This output goes to STDOUT unless you've
redirected it with select().)
(F) This is an educated guess made in conjunction with the message "Can't locate object method \"%s\" via package \"%s\"". It often means that a method requires a package that has not been loaded.
(F) The module in question uses features of a version of Perl more recent than the currently running version. How long has it been since you upgraded, anyway? See require.
(F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the
sh
-shell in. See "PERL_SH_DIR" in perlos2.
See PERL_SIGNALS in perlrun for legal values.
(S) The whole warning message will look something like:
- perl: warning: Setting locale failed.
- perl: warning: Please check that your locale settings:
- LC_ALL = "En_US",
- LANG = (unset)
- are supported and installed on your system.
- perl: warning: Falling back to the standard locale ("C").
Exactly what were the failed locale settings varies. In the above the settings were that the LC_ALL was "En_US" and the LANG had no value. This error means that Perl detected that you and/or your operating system supplier and/or system administrator have set up the so-called locale system but Perl could not use those settings. This was not dead serious, fortunately: there is a "default locale" called "C" that Perl can and will use, the script will be run. Before you really fix the problem, however, you will get the same error message each time you run Perl. How to really fix the problem can be found in perllocale section LOCALE PROBLEMS.
(F) The setuid emulator in suidperl decided you were up to no good.
(W exec) A warning peculiar to VMS. Waitpid() was asked to wait for a process which isn't a subprocess of the current process. While this is fine from VMS' perspective, it's probably not what you intended.
(F) The unpack format P must have an explicit size, not "*".
(F) The script would have to be opened by the C preprocessor by name, which provides a race condition that breaks security.
(F) The class in the character class [: :] syntax is unknown. The <-- HERE
shows in the regular expression about where the problem was discovered.
Note that the POSIX character classes do not have the is
prefix
the corresponding C interfaces have: in other words, it's [[:print:]],
not isprint
. See perlre.
(F) Your system has POSIX getpgrp(), which takes no argument, unlike the BSD version, which takes a pid.
(W regexp) The character class constructs [: :], [= =], and [. .] go inside character classes, the [] are part of the construct, for example: /[012[:alpha:]345]/. Note that [= =] and [. .] are not currently implemented; they are simply placeholders for future extensions and will cause fatal errors. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F regexp) Within regular expression character classes ([]) the syntax beginning with "[." and ending with ".]" is reserved for future extensions. If you need to represent those character sequences inside a regular expression character class, just quote the square brackets with the backslash: "\[." and ".\]". The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) Within regular expression character classes ([]) the syntax beginning with "[=" and ending with "=]" is reserved for future extensions. If you need to represent those character sequences inside a regular expression character class, just quote the square brackets with the backslash: "\[=" and "=\]". The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(W qw) qw() lists contain items separated by whitespace; as with literal strings, comment characters are not ignored, but are instead treated as literal data. (You may have used different delimiters than the parentheses shown here; braces are also frequently used.)
You probably wrote something like this:
- @list = qw(
- a # a comment
- b # another comment
- );
when you should have written this:
- @list = qw(
- a
- b
- );
If you really want comments, build your list the old-fashioned way, with quotes and commas:
- @list = (
- 'a', # a comment
- 'b', # another comment
- );
(W qw) qw() lists contain items separated by whitespace; therefore commas aren't needed to separate the items. (You may have used different delimiters than the parentheses shown here; braces are also frequently used.)
You probably wrote something like this:
- qw! a, b, c !;
which puts literal commas into some of the list items. Write it without commas if you don't want them to appear in your data:
- qw! a b c !;
(F) An ioctl() or fcntl() returned more than Perl was bargaining for. Perl guesses a reasonable buffer size, but puts a sentinel byte at the end of the buffer just in case. This sentinel byte got clobbered, and Perl assumes that memory is now corrupted. See ioctl.
(W precedence) Your program uses a bitwise logical operator in conjunction with a numeric comparison operator, like this :
- if ($x & $y == 0) { ... }
This expression is actually equivalent to $x & ($y == 0)
, due to the
higher precedence of ==
. This is probably not what you want. (If you
really meant to write this, disable the warning, or, better, put the
parentheses explicitly and write $x & ($y == 0)
).
(W ambiguous) You said something like `@foo' in a double-quoted string
but there was no array @foo
in scope at the time. If you wanted a
literal @foo, then write it as \@foo; otherwise find out what happened
to the array you apparently lost track of.
(W y2k) You are concatenating the number 19 with another number, which could be a potential Year 2000 problem.
(D deprecated) You have written something like this:
- sub doit
- {
- use attrs qw(locked);
- }
You should use the new declaration syntax instead.
- sub doit : locked
- {
- ...
The use attrs
pragma is now obsolete, and is only provided for
backward-compatibility. See Subroutine Attributes in perlsub.
(S precedence) The old irregular construct
is now misinterpreted as
because of the strict regularization of Perl 5's grammar into unary and list operators. (The old open was a little of both.) You must put parentheses around the filehandle, or use the new "or" operator instead of "||".
See Server error.
(W closed) The filehandle you're writing to got itself closed sometime before now. Check your control flow.
(W closed) The filehandle you're printing on got itself closed sometime before now. Check your control flow.
(W) This is a standard message issued by OS/2 applications, while *nix applications die in silence. It is considered a feature of the OS/2 port. One can easily disable this by appropriate sighandlers, see Signals in perlipc. See also "Process terminated by SIGTERM/SIGINT" in perlos2.
(S prototype) The subroutine being declared or defined had previously been declared or defined with a different function prototype.
(F) You've omitted the closing parenthesis in a function prototype definition.
(D deprecated) Pseudo-hashes were deprecated in Perl 5.8.0 and they
will be removed in Perl 5.10.0, see perl58delta for more details.
You can continue to use the fields
pragma.
(F) You started a regular expression with a quantifier. Backslash it if you meant it literally. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) There is currently a limit to the size of the min and max values of the {min,max} construct. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(W regexp) You applied a regular expression quantifier in a place where
it makes no sense, such as on a zero-width assertion. Try putting the
quantifier inside the assertion instead. For example, the way to match
"abc" provided that it is followed by three repetitions of "xyz" is
/abc(?=(?:xyz){3})/
, not /abc(?=xyz){3}/
.
The <-- HERE shows in the regular expression about where the problem was discovered.
(F) One (or both) of the numeric arguments to the range operator ".." are outside the range which can be represented by integers internally. One possible workaround is to force Perl to use magical string increment by prepending "0" to your numbers.
(W io) The dirhandle you're reading from is either closed or not really a dirhandle. Check your control flow.
(W closed) The filehandle you're reading from got itself closed sometime before now. Check your control flow.
(W closed) You tried to read from a closed filehandle.
(W unopened) You tried to read from a filehandle that was never opened.
(F) You can't allocate more than 64K on an MS-DOS machine.
(S malloc) An internal routine called realloc() on something that had already been freed.
(F debugging) You can't use the -D option unless the code to produce the desired output is compiled into Perl, which entails some overhead, which is why it's currently left out of your copy.
(F) More than 100 levels of inheritance were used. Probably indicates an unintended loop in your inheritance hierarchy.
(F) More than 100 levels of inheritance were encountered while invoking a method. Probably indicates an unintended loop in your inheritance hierarchy.
(W misc) You gave a single reference where Perl was expecting a list with an even number of elements (for assignment to a hash). This usually means that you used the anon hash constructor when you meant to use parens. In any case, a hash requires key/value pairs.
- %hash = { one => 1, two => 2, }; # WRONG
- %hash = [ qw/ an anon array / ]; # WRONG
- %hash = ( one => 1, two => 2, ); # right
- %hash = qw( one 1 two 2 ); # also fine
(W misc) You have attempted to weaken a reference that is already weak. Doing so has no effect.
(W internal) The internal sv_replace() function was handed a new SV with a reference count of other than 1.
(F) You used something like \7
in your regular expression, but there are
not at least seven sets of capturing parentheses in the expression. If you
wanted to have the character with value 7 inserted into the regular expression,
prepend a zero to make the number at least two digits: \07
The <-- HERE shows in the regular expression about where the problem was discovered.
(P) The regular expression engine got confused by what the regular expression compiler gave it.
(P) A "can't happen" error, because safemalloc() should have caught it earlier.
(F) Your format contains the ~~ repeat-until-blank sequence and a numeric field that will never go blank so that the repetition never terminates. You might use ^# instead. See perlform.
(W syntax) You wrote your assignment operator backwards. The = must always comes last, to avoid ambiguity with subsequent unary operators.
(W io) The dirhandle you tried to do a rewinddir() on is either closed or not really a dirhandle. Check your control flow.
(F) Your format contained the ~~ repeat-until-blank sequence, but it produced 200 lines at once, and the 200th line looked exactly like the 199th line. Apparently you didn't arrange for the arguments to exhaust themselves, either by using ^ instead of @ (for scalar variables), or by shifting or popping (for array variables). See perlform.
(P) Something went wrong in Perl's internal bookkeeping of scalars: not all scalar variables were deallocated by the time Perl exited. What this usually indicates is a memory leak, which is of course bad, especially if the Perl program is intended to be long-running.
(W syntax) You've used an array slice (indicated by @) to select a
single element of an array. Generally it's better to ask for a scalar
value (indicated by $). The difference is that $foo[&bar]
always
behaves like a scalar, both when assigning to it and when evaluating its
argument, while @foo[&bar]
behaves like a list when you assign to it,
and provides a list context to its subscript, which can do weird things
if you're expecting only one subscript.
On the other hand, if you were actually hoping to treat the array element as a list, you need to look into how references work, because Perl will not magically convert between scalars and lists for you. See perlref.
(W syntax) You've used a hash slice (indicated by @) to select a single
element of a hash. Generally it's better to ask for a scalar value
(indicated by $). The difference is that $foo{&bar}
always behaves
like a scalar, both when assigning to it and when evaluating its
argument, while @foo{&bar}
behaves like a list when you assign to it,
and provides a list context to its subscript, which can do weird things
if you're expecting only one subscript.
On the other hand, if you were actually hoping to treat the hash element as a list, you need to look into how references work, because Perl will not magically convert between scalars and lists for you. See perlref.
(F) Oddly, the suidperl program was invoked on a script without a setuid or setgid bit set. This doesn't make much sense.
(F) The lexer couldn't find the final delimiter of a // or m{}
construct. Remember that bracketing delimiters count nesting level.
Missing the leading $
from a variable $m
may cause this error.
Note that since Perl 5.9.0 a // can also be the defined-or construct, not just the empty search pattern. Therefore code written in Perl 5.9.0 or later that uses the // as the defined-or can be misparsed by pre-5.9.0 Perls as a non-terminated search pattern.
(F) The lexer couldn't find the final delimiter of a ?PATTERN?
construct.
The question mark is also used as part of the ternary operator (as in
foo ? 0 : 1
) leading to some ambiguous constructions being wrongly
parsed. One way to disambiguate the parsing is to put parentheses around
the conditional expression, i.e. (foo) ? 0 : 1
.
(W unopened) You tried to use the seek() or sysseek() function on a filehandle that was either never opened or has since been closed.
(W io) The dirhandle you are doing a seekdir() on is either closed or not really a dirhandle. Check your control flow.
(F) This machine doesn't implement the select() system call.
(F) Self-ties are of arrays and hashes are not supported in the current implementation.
(W semicolon) A nearby syntax error was probably caused by a missing semicolon, or possibly some other missing operator, such as a comma.
(S internal) The internal newSVsv() routine was called to duplicate a scalar that had previously been marked as free.
(F) You don't have System V semaphore IPC on your system.
(W closed) The socket you're sending to got itself closed sometime before now. Check your control flow.
(F) A regular expression ended with an incomplete extension (?. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) A proposed regular expression extension has the character reserved but has not yet been written. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) You used a regular expression extension that doesn't make sense. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) A regular expression comment must be terminated by a closing parenthesis. Embedded parentheses aren't allowed. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) If the contents of a (?{...}) clause contains braces, they must balance for Perl to properly detect the end of the clause. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
See Server error.
This is the error message generally seen in a browser window when trying to run a CGI program (including SSI) over the web. The actual error text varies widely from server to server. The most frequently-seen variants are "500 Server error", "Method (something) not permitted", "Document contains no data", "Premature end of script headers", and "Did not produce a valid header".
This is a CGI error, not a Perl error.
You need to make sure your script is executable, is accessible by the user CGI is running the script under (which is probably not the user account you tested it under), does not rely on any environment variables (like PATH) from the user it isn't running under, and isn't in a location where the CGI server can't find it, basically, more or less. Please see the following for more information:
- http://www.perl.org/CGI_MetaFAQ.html
- http://www.htmlhelp.org/faq/cgifaq.html
- http://www.w3.org/Security/Faq/
You should also look at perlfaq9.
(F) You tried to assign to $)
, and your operating system doesn't
support the setegid() system call (or equivalent), or at least Configure
didn't think so.
(F) You tried to assign to $>
, and your operating system doesn't
support the seteuid() system call (or equivalent), or at least Configure
didn't think so.
(F) Your system has the setpgrp() from BSD 4.2, which takes no arguments, unlike POSIX setpgid(), which takes a process ID and process group ID.
(F) You tried to assign to $(
, and your operating system doesn't
support the setrgid() system call (or equivalent), or at least Configure
didn't think so.
(F) You tried to assign to $<
, and your operating system doesn't
support the setruid() system call (or equivalent), or at least Configure
didn't think so.
(W closed) You tried to set a socket option on a closed socket. Did you forget to check the return value of your socket() call? See setsockopt.
(F) The setuid emulator won't run a script that is writable by the world, because the world might have written on it already.
(F) The setuid emulator won't run a script that isn't read from a file, but from a socket, a pipe or another device.
(F) You don't have System V shared memory IPC on your system.
(F) You wrote require <file>
when you should have written
require 'file'
.
(W syntax) You have used a pattern where Perl expected to find a string,
as in the first argument to join. Perl will treat the true or false
result of matching the pattern against $_ as the string, which is
probably not what you had in mind.
(W closed) You tried to do a shutdown on a closed socket. Seems a bit superfluous.
(W signal) The signal handler named in %SIG doesn't, in fact, exist. Perhaps you put it into the wrong package?
(F) An ancient error message that almost nobody ever runs into anymore. But before sort was a keyword, people sometimes used it as a filehandle.
(F) A sort comparison routine must return a number. You probably blew
it by not using <=>
or cmp
, or by not using them correctly.
See sort.
(F) A sort comparison subroutine may not return a list value with more or less than one element. See sort.
(W misc) You attempted to specify an offset that was past the end of the array passed to splice(). Splicing will instead commence at the end of the array, rather than past it. If this isn't what you want, try explicitly pre-extending the array by assigning $#array = $offset. See splice.
(P) The split was looping infinitely. (Obviously, a split shouldn't iterate more times than there are characters of input, which is what happened.) See split.
(W exec) You did an exec() with some statement after it other than a die(). This is almost always an error, because exec() never returns unless there was a failure. You probably wanted to use system() instead, which does return. To suppress this warning, put the exec() in a block by itself.
(W unopened) You tried to use the stat() function on a filehandle that was either never opened or has since been closed.
(P) Overloading resolution over @ISA tree may be broken by importation
stubs. Stubs should never be implicitly created, but explicit calls to
can
may break this.
(W redefine) You redefined a subroutine. To suppress this warning, say
(P) The substitution was looping infinitely. (Obviously, a substitution shouldn't iterate more times than there are characters of input, which is what happened.) See the discussion of substitution in Regexp Quote-Like Operators in perlop.
(F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
construct. Remember that bracketing delimiters count nesting level.
Missing the leading $
from variable $s
may cause this error.
(F) The lexer couldn't find the final delimiter of an s/// or s{}{}
construct. Remember that bracketing delimiters count nesting level.
Missing the leading $
from variable $s
may cause this error.
(W substr),(F) You tried to reference a substr() that pointed outside of a string. That is, the absolute value of the offset was larger than the length of the string. See substr. This warning is fatal if substr is used in an lvalue context (as the left hand side of an assignment or as a subroutine argument for example).
(F) Your Perl was compiled with -DSETUID_SCRIPTS_ARE_SECURE_NOW, but a version of the setuid emulator somehow got run anyway.
(F) A (?(condition)if-clause|else-clause) construct can have at most two
branches (the if-clause and the else-clause). If you want one or both to
contain alternation, such as using this|that|other
, enclose it in
clustering parentheses:
- (?(condition)(?:this|that|other)|else-clause)
The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) If the argument to the (?(...)if-clause|else-clause) construct is a number, it can be only a number. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) While under the use filetest
pragma, we cannot switch the real
and effective uids or gids.
(F) The final summary message when a perl -c
succeeds.
(F) Probably means you had a syntax error. Common reasons include:
- A keyword is misspelled.
- A semicolon is missing.
- A comma is missing.
- An opening or closing parenthesis is missing.
- An opening or closing brace is missing.
- A closing quote is missing.
Often there will be another error message associated with the syntax
error giving more information. (Sometimes it helps to turn on -w.)
The error message itself often tells you where it was in the line when
it decided to give up. Sometimes the actual error is several tokens
before this, because Perl is good at understanding random input.
Occasionally the line number may be misleading, and once in a blue moon
the only way to figure out what's triggering the error is to call
perl -c
repeatedly, chopping away half the program each time to see
if the error went away. Sort of the cybernetic version of 20
questions.
(A) You've accidentally run your script through the Bourne shell instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(F) This error is likely to occur if you run a perl5 script through a perl4 interpreter, especially if the next 2 tokens are "use strict" or "my $var" or "our $var".
(W closed) You tried to read from a closed filehandle.
(W unopened) You tried to read from a filehandle that was never opened.
(F) You tried to do something with a function beginning with "sem", "shm", or "msg" but that System V IPC is not implemented in your machine. In some machines the functionality can exist but be unconfigured. Consult your system support.
(W closed) The filehandle you're writing to got itself closed sometime before now. Check your control flow.
-T
and -B
not implemented on filehandles
(F) Perl can't peek at the stdio buffer of filehandles when it doesn't know about your kind of stdio. You'll have to use a filename instead.
(F) You tried to use goto to reach a label that was too deeply nested
for Perl to reach. Perl is doing you a favor by refusing.
(W unopened) You tried to use the tell() function on a filehandle that was either never opened or has since been closed.
(W io) The dirhandle you tried to telldir() is either closed or not really a dirhandle. Check your control flow.
(F) Assignment to $[
is now strictly circumscribed, and interpreted
as a compiler directive. You may say only one of
This is to prevent the problem of one module changing the array base out from under another module inadvertently. See $[ in perlvar.
(F) Configure couldn't find the crypt() function on your machine, probably because your vendor didn't supply it, probably because they think the U.S. Government thinks it's a secret, or at least that they will continue to pretend that it is. And if you quote me on that, I will deny it.
The function indicated isn't implemented on this architecture, according to the probings of Configure.
(F) It makes no sense to test the current stat buffer for symbolic linkhood if the last stat that wrote to the stat buffer already went past the symlink to get to the real file. Use an actual filename instead.
(F) Currently this attribute is not supported on my or sub
declarations. See our.
(W internal) Warnings peculiar to VMS. You tried to change or delete an element of the CRTL's internal environ array, but your copy of Perl wasn't built with a CRTL that contained the setenv() function. You'll need to rebuild Perl with a CRTL that does, or redefine PERL_ENV_TABLES (see perlvms) so that the environ array isn't the target of the change to %ENV which produced the warning.
(W threads)(S) The entry point function of threads->create() failed for some reason.
(D deprecated) The 5.005-style threads (activated by use Thread;
)
are deprecated and one should use the new ithreads instead,
see perl58delta for more details.
(F) Your version of the C library apparently doesn't do times(). I suspect you're not running on Unix.
(X) The #! line (or local equivalent) in a Perl script contains the -T option, but Perl was not invoked with -T in its command line. This is an error because, by the time Perl discovers a -T in a script, it's too late to properly taint everything from the environment. So Perl gives up.
If the Perl script is being executed as a command using the #!
mechanism (or its local equivalent), this error can usually be fixed by
editing the #! line so that the -T option is a part of Perl's first
argument: e.g. change perl -n -T
to perl -T -n
.
If the Perl script is being executed as perl scriptname
, then the
-T option must appear on the command line: perl -T scriptname
.
(F) You tried to define a customized To-mapping for lc(), lcfirst, uc(), or ucfirst() (or their string-inlined versions), but you specified an illegal mapping. See User-Defined Character Properties in perlunicode.
(F) Your template contains ()-groups with a ridiculously deep nesting level.
(F) There has to be at least one argument to syscall() to specify the system call to call, silly dilly.
(X) The #! line (or local equivalent) in a Perl script contains the
-M or -m option. This is an error because -M and -m options
are not intended for use inside scripts. Use the use pragma instead.
(W void) A CHECK or INIT block is being defined during run time proper,
when the opportunity to run them has already passed. Perhaps you are
loading a file with require or do when you should be using use
instead. Or perhaps you should put the require or do inside a
BEGIN block.
(F) Perl supports a maximum of only 14 args to syscall().
(F) The function requires fewer arguments than you specified.
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(F) The regular expression ends with an unbackslashed backslash. Backslash it. See perlre.
(F) The lexer couldn't find the interior delimiter of a tr/// or tr[][]
or y/// or y[][] construct. Missing the leading $
from variables
$tr
or $y
may cause this error.
(F) The lexer couldn't find the final delimiter of a tr///, tr[][], y/// or y[][] construct.
(F) You tried to use an operator from a Safe compartment in which it's disallowed. See Safe.
(F) Your machine doesn't implement a file truncation mechanism that Configure knows about.
(F) This function requires the argument in that position to be of a
certain type. Arrays must be @NAME or @{EXPR}
. Hashes must be
%NAME or %{EXPR}
. No implicit dereferencing is allowed--use the
{EXPR} forms as an explicit dereference. See perlref.
(F) Your machine doesn't implement the umask function and you tried to use it to restrict permissions for yourself (EXPR & 0700).
(F) You attempted to create or access a subroutine with an illegal name.
(W internal) The exit code detected an internal inconsistency in how many execution contexts were entered and left.
(W internal) The exit code detected an internal inconsistency in how many values were temporarily localized.
(W internal) The exit code detected an internal inconsistency in how many blocks were entered and left.
(W internal) The exit code detected an internal inconsistency in how many mortal scalars were allocated and freed.
(F) The format indicated doesn't seem to exist. Perhaps it's really in another package? See perlform.
(F) The sort comparison routine specified doesn't seem to exist. Perhaps it's in a different package? See sort.
(F) The subroutine indicated hasn't been defined, or if it was, it has since been undefined.
(F) The anonymous subroutine you're trying to call hasn't been defined, or if it was, it has since been undefined.
(F) The sort comparison routine specified is declared but doesn't seem to have been defined yet. See sort.
(F) The format indicated doesn't seem to exist. Perhaps it's really in another package? See perlform.
(W misc) An undefined value was assigned to a typeglob, a la
*foo = undef
. This does nothing. It's possible that you really mean
undef *foo
.
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(F) The unexec() routine failed for some reason. See your local FSF representative, who probably put it there in the first place.
(W utf8) Certain Unicode characters have been designated off-limits by
the Unicode standard and should not be generated. If you really know
what you are doing you can turn off this warning by no warnings 'utf8';
.
(F) There are no byte-swapping functions for a machine with this byte order.
(F) The second argument of 3-argument open() is not among the list
of valid modes: <
, >, >>
, +<
,
+>, +>>
, -|, |-, <&
, >&.
(W layer) An attempt was made to push an unknown layer onto the Perl I/O
system. (Layers take care of transforming data between external and
internal representations.) Note that some layers, such as mmap
,
are not supported in all environments. If your program didn't
explicitly request the failing operation, it may be the result of the
value of the environment variable PERLIO.
(P) An error peculiar to VMS. Perl was reading values for %ENV before iterating over it, and someone else stuck a message in the stream of data Perl expected. Someone's very confused, or perhaps trying to subvert Perl's population of %ENV for nefarious purposes.
You tried to use an unknown subpragma of the "re" pragma.
(F) The condition part of a (?(condition)if-clause|else-clause) construct is not known. The condition may be lookahead or lookbehind (the condition is true if the lookahead or lookbehind is true), a (?{...}) construct (the condition is true if the code evaluates to a true value), or a number (the condition is true if the set of capturing parentheses named by the number matched).
The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
You specified an unknown Unicode option. See perlrun documentation
of the -C
switch for the list of known options.
You specified an unknown Unicode option. See perlrun documentation
of the -C
switch for the list of known options.
(F) An error issued by the warnings
pragma. You specified a warnings
category that is unknown to perl at this point.
Note that if you want to enable a warnings category registered by a module
(e.g. use warnings 'File::Find'
), you must have imported this module
first.
(F) The brackets around a character class must match. If you wish to include a closing bracket in a character class, backslash it or put it first. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) Unbackslashed parentheses must always be balanced in regular expressions. If you're a vi user, the % key is valuable for finding the matching parenthesis. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(F) The lexer counted more closing curly or square brackets than opening ones, so you're probably missing a matching opening bracket. As a general rule, you'll find the missing one (so to speak) near the place you were last editing.
(W reserved) You used a bareword that might someday be claimed as a reserved word. It's best to put such a word in quotes, or capitalize it somehow, or insert an underbar into it. You might also declare it as a subroutine.
(F) The Perl parser has no idea what to do with the specified character in your Perl script (or eval) at the specified column. Perhaps you tried to run a compressed script, a binary program, or a directory as a Perl program.
(W regexp) You used a backslash-character combination which is not recognized by Perl inside character classes. The character was understood literally.
(W misc) You used a backslash-character combination which is not recognized by Perl.
(W regexp) You used a backslash-character combination which is not
recognized by Perl. This combination appears in an interpolated variable or
a '-delimited regular expression. The character was understood
literally. The <-- HERE shows in the regular expression about where the
escape was discovered.
(F) You specified a signal name to the kill() function that was not
recognized. Say kill -l
in your shell to see the valid signal names
on your system.
(F) You specified an illegal option to Perl. Don't do that. (If you think you didn't do that, check the #! line to see if it's supplying the bad switch on your behalf.)
(W newline) A file operation was attempted on a filename, and that operation failed, PROBABLY because the filename contained a newline, PROBABLY because you forgot to chomp() it off. See chomp.
(F) Your machine doesn't support opendir() and readdir().
(F) This machine doesn't implement the indicated function, apparently. At least, Configure doesn't think so.
(F) Your version of executable does not support forking.
Note that under some systems, like OS/2, there may be different flavors
of Perl executables, some of which may support fork, some not. Try
changing the name you call Perl by to perl_
, perl__
, and so on.
(F) Your program file begins with a Unicode Byte Order Mark (BOM) which declares it to be in a Unicode encoding that Perl cannot read.
(F) Your machine doesn't support the Berkeley socket mechanism, or at least that's what Configure thought.
(F) The lexer found something other than a simple identifier at the start of an attribute, and it wasn't a semicolon or the start of a block. Perhaps you terminated the parameter list of the previous attribute too soon. See attributes.
(F) The lexer saw an opening (left) parenthesis character while parsing an attribute list, but the matching closing (right) parenthesis character was not found. You may need to add (or remove) a backslash character to get your parentheses to balance. See attributes.
(F) An argument to unpack("w",...) was incompatible with the BER compressed integer format and could not be converted to an integer. See pack.
(F) The lexer saw a left angle bracket in a place where it was expecting a term, so it's looking for the corresponding right angle bracket, and not finding it. Chances are you left some needed parentheses out earlier in the line, and you really meant a "less than".
(W untie) A copy of the object returned from tie (or tied) was
still valid when untie was called.
(F) You called a POSIX function with incorrect arguments. See FUNCTIONS in POSIX for more information.
(F) You called a Win32 function with incorrect arguments. See Win32 for more information.
(W regexp) You have used an internal modifier such as (?-o) that has no meaning unless removed from the entire regexp:
- if ($string =~ /(?-o)$pattern/o) { ... }
must be written as
- if ($string =~ /$pattern/) { ... }
The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(W regexp) You have used an internal modifier such as (?o) that has no meaning unless applied to the entire regexp:
- if ($string =~ /(?o)$pattern/) { ... }
must be written as
- if ($string =~ /$pattern/o) { ... }
The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(W void) You did something without a side effect in a context that does nothing with the return value, such as a statement that doesn't return a value from a block, or the left side of a scalar comma operator. Very often this points not to stupidity on your part, but a failure of Perl to parse your program the way you thought it would. For example, you'd get this if you mixed up your C precedence with Python precedence and said
- $one, $two = 1, 2;
when you meant to say
- ($one, $two) = (1, 2);
Another common error is to use ordinary parentheses to construct a list reference when you should be using square or curly brackets, for example, if you say
- $array = (1,2);
when you should have said
- $array = [1,2];
The square brackets explicitly turn a list value into a scalar value, while parentheses do not. So when a parenthesized list is evaluated in a scalar context, the comma is treated like C's comma operator, which throws away the left argument, which is not what you want. See perlref for more on this.
This warning will not be issued for numerical constants equal to 0 or 1 since they are often used in statements like
- 1 while sub_with_side_effects();
String constants that would normally evaluate to 0 or 1 are warned about.
(W) You did use re;
without any arguments. That isn't very useful.
(W void) You used sort in scalar context, as in :
This is not very useful, and perl currently optimizes this away.
(W syntax) You used the push() or unshift() function with no arguments
apart from the array, like push(@x) or unshift(@foo). That won't
usually have any effect on the array, so is completely useless. It's
possible in principle that push(@tied_array) could have some effect
if the array is tied to a class which implements a PUSH method. If so,
you can write it as push(@tied_array,()) to avoid this warning.
(F) The "use" keyword is recognized and executed at compile time, and returns no useful value. See perlmod.
(D deprecated) You are now encouraged to use the explicitly quoted form if you wish to use an empty line as the terminator of the here-document.
(D deprecated) chdir() with no arguments is documented to change to $ENV{HOME} or $ENV{LOGDIR}. chdir(undef) and chdir('') share this behavior, but that has been deprecated. In future versions they will simply fail.
Be careful to check that what you pass to chdir() is defined and not blank, else you might find yourself in your home directory.
(W regexp) You used the /c modifier in a substitution. The /c modifier is not presently meaningful in substitutions.
(W regexp) You used the /c modifier with a regex operand, but didn't use the /g modifier. Currently, /c is meaningful only when /g is used. (This may change in the future.)
(F) Perhaps you modified the iterated array within the loop? This error is typically caused by code like the following:
- @a = (3,4);
- @a = () for (1,2,@a);
You are not supposed to modify arrays while they are being iterated over. For speed and efficiency reasons, Perl internally does not do full reference-counting of iterated items, hence deleting such an item in the middle of an iteration causes Perl to see a freed value.
(D deprecated) You are now encouraged to use the shorter *glob{IO} form to access the filehandle slot within a typeglob.
(W regexp) You used the /g modifier on the pattern for a split
operator. Since split always tries to match the pattern
repeatedly, the /g has no effect.
(D deprecated) It makes a lot of work for the compiler when you clobber a subroutine's argument list, so it's better if you assign the results of a split() explicitly to an array (or list).
(D deprecated) As an (ahem) accidental feature, AUTOLOAD
subroutines
are looked up as methods (using the @ISA
hierarchy) even when the
subroutines to be autoloaded were called as plain functions (e.g.
Foo::bar()
), not as methods (e.g. Foo->bar()
or $obj->bar()
).
This bug will be rectified in future by using method lookup only for
methods' AUTOLOAD
s. However, there is a significant base of existing
code that may be using the old behavior. So, as an interim step, Perl
currently issues an optional warning when non-methods use inherited
AUTOLOAD
s.
The simple rule is: Inheritance will not work when autoloading
non-methods. The simple fix for old code is: In any module that used
to depend on inheriting AUTOLOAD
for non-methods from a base class
named BaseClass
, execute *AUTOLOAD = \&BaseClass::AUTOLOAD
during
startup.
In code that currently says use AutoLoader; @ISA = qw(AutoLoader);
you should remove AutoLoader from @ISA and change use AutoLoader;
to
use AutoLoader 'AUTOLOAD';
.
(F) You attempted to use a feature of printf that is accessible from only C. This usually means there's a better way to do it in Perl.
(D deprecated) This variable magically turned on multi-line pattern
matching, both for you and for any luckless subroutine that you happen
to call. You should use the new //m
and //s
modifiers now to do
that without the dangerous action-at-a-distance effects of $*
.
(D deprecated) This was an ill-advised attempt to emulate a poorly defined awk feature. Use an explicit printf() or sprintf() instead.
(D deprecated) The construct indicated is no longer recommended for use, generally because there's a better way to do it, and also because the old way has bad side effects.
(W io) A filehandle represents an opened file, and when you opened the file
it already went past any symlink you are presumably trying to look for.
The operation returned undef. Use a filename instead.
(D deprecated) You used the package keyword without specifying a package
name. So no namespace is current at all. Using this can cause many
otherwise reasonable constructs to fail in baffling ways. use strict;
instead.
(W misc) You tried to use a reference as an array index; this probably isn't what you mean, because references in numerical context tend to be huge numbers, and so usually indicates programmer error.
If you really do mean it, explicitly numify your reference, like so:
$array[0+$ref]
. This warning is not given for overloaded objects,
either, because you can overload the numification and stringification
operators and then you assumably know what you are doing.
(D deprecated) The indicated bareword is a reserved word. Future
versions of perl may use it as a keyword, so you're better off either
explicitly quoting the word in a manner appropriate for its context of
use, or using a different name altogether. The warning can be
suppressed for subroutine names by either adding a &
prefix, or using
a package qualifier, e.g. &our()
, or Foo::our()
.
(W taint, deprecated) You have supplied system() or exec() with multiple
arguments and at least one of them is tainted. This used to be allowed
but will become a fatal error in a future version of perl. Untaint your
arguments. See perlsec.
(W uninitialized) An undefined value was used as if it were already defined. It was interpreted as a "" or a 0, but maybe it was a mistake. To suppress this warning assign a defined value to your variables.
To help you figure out what was undefined, perl tells you what operation
you used the undefined value in. Note, however, that perl optimizes your
program and the operation displayed in the warning may not necessarily
appear literally in your program. For example, "that $foo"
is
usually optimized into "that " . $foo
, and the warning will refer to
the concatenation (.) operator, even though there is no . in your
program.
(D deprecated) You tried to use a hash as a reference, as in
%foo->{"bar"}
or %$ref->{"hello"}
. Versions of perl <= 5.6.1
used to allow this syntax, but shouldn't have. It is now deprecated, and will
be removed in a future version.
(D deprecated) You tried to use an array as a reference, as in
@foo->[23]
or @$ref->[99]
. Versions of perl <= 5.6.1 used to
allow this syntax, but shouldn't have. It is now deprecated, and will be
removed in a future version.
(W utf8) You tried to generate half of an UTF-16 surrogate by
requesting a Unicode character between the code points 0xD800 and
0xDFFF (inclusive). That range is reserved exclusively for the use of
UTF-16 encoding (by having two 16-bit UCS-2 characters); but Perl
encodes its characters in UTF-8, so what you got is a very illegal
character. If you really know what you are doing you can turn off
this warning by no warnings 'utf8';
.
(W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
each(), or readdir() as a boolean value. Each of these constructs
can return a value of "0"; that would make the conditional expression
false, which is probably not what you intended. When using these
constructs in conditional expressions, test their values with the
defined operator.
(W misc) A warning peculiar to VMS. Perl tried to read the value of an %ENV element from a CLI symbol table, and found a resultant string longer than 1024 characters. The return value has been truncated to 1024 characters.
(F) While "use strict" in effect, you referred to a global variable that you apparently thought was imported from another module, because something else of the same name (usually a subroutine) is exported by that module. It usually means you put the wrong funny character on the front of your variable.
(F) Lookbehind is allowed only for subexpressions whose length is fixed and known at compile time. The <-- HERE shows in the regular expression about where the problem was discovered. See perlre.
(W misc) A "my" or "our" variable has been redeclared in the current scope or statement, effectively eliminating all access to the previous instance. This is almost always a typographical error. Note that the earlier variable will still exist until the end of the scope or until all closure referents to it are destroyed.
(W closure) An inner (nested) anonymous subroutine is inside a named subroutine, and outside that is another subroutine; and the anonymous (innermost) subroutine is referencing a lexical variable defined in the outermost subroutine. For example:
If the anonymous subroutine is called or referenced (directly or indirectly) from the outermost subroutine, it will share the variable as you would expect. But if the anonymous subroutine is called or referenced when the outermost subroutine is not active, it will see the value of the shared variable as it was before and during the *first* call to the outermost subroutine, which is probably not what you want.
In these circumstances, it is usually best to make the middle subroutine
anonymous, using the sub {}
syntax. Perl has specific support for
shared variables in nested anonymous subroutines; a named subroutine in
between interferes with this feature.
(A) You've accidentally run your script through csh instead of Perl. Check the #! line, or manually feed your script into Perl yourself.
(W closure) An inner (nested) named subroutine is referencing a lexical variable defined in an outer subroutine.
When the inner subroutine is called, it will probably see the value of the outer subroutine's variable as it was before and during the *first* call to the outer subroutine; in this case, after the first call to the outer subroutine is complete, the inner and outer subroutines will no longer share a common value for the variable. In other words, the variable will no longer be shared.
Furthermore, if the outer subroutine is anonymous and references a lexical variable outside itself, then the outer and inner subroutines will never share the given variable.
This problem can usually be solved by making the inner subroutine
anonymous, using the sub {}
syntax. When inner anonymous subs that
reference variables in outer subroutines are called or referenced, they
are automatically rebound to the current values of such variables.
(P) The attempt to translate a use Module n.n LIST
statement into
its equivalent BEGIN
block found an internal inconsistency with
the version number.
(W) You passed warn() an empty string (the equivalent of warn ""
) or
you called it with no args and $@
was empty.
(S) The implicit close() done by an open() got an error indication on the close(). This usually indicates your file system ran out of disk space.
(S ambiguous) You wrote a unary operator followed by something that looks like a binary operator that could also have been interpreted as a term or unary operator. For instance, if you know that the rand function has a default argument of 1.0, and you write
- rand + 5;
you may THINK you wrote the same thing as
- rand() + 5;
but in actual fact, you got
- rand(+5);
So put in parentheses to say what you really mean.
(W utf8) Perl met a wide character (>255) when it wasn't expecting
one. This warning is by default on for I/O (like print). The easiest
way to quiet this warning is simply to add the :utf8
layer to the
output, e.g. binmode STDOUT, ':utf8'
. Another way to turn off the
warning is to add no warnings 'utf8';
but that is often closer to
cheating. In general, you are supposed to explicitly mark the
filehandle with an encoding, see open and binmode.
(F) The count in the (un)pack template may be replaced by [TEMPLATE]
only if
TEMPLATE
always matches the same amount of packed bytes that can be
determined from the template alone. This is not possible if it contains an
of the codes @, /, U, u, w or a *-length. Redesign the template.
(W closed) The filehandle you're writing to got itself closed sometime before now. Check your control flow.
When reading in different encodings Perl tries to map everything into Unicode characters. The bytes you read in are not legal in this encoding, for example
- utf8 "\xE4" does not map to Unicode
if you try to read in the a-diaereses Latin-1 as UTF-8.
(F) You had a (un)pack template that specified a relative position before the beginning of the string being (un)packed. See pack.
(F) You had a pack template that specified a relative position after the end of the string being unpacked. See pack.
(F) And you probably never will, because you probably don't have the sources to your kernel, and your vendor probably doesn't give a rip about what you want. Your best bet is to put a setuid C wrapper around your script.
(W syntax) You assigned a bareword as a signal handler name. Unfortunately, you already have a subroutine of that name declared, which means that Perl 5 will try to call the subroutine when the assignment is executed, which is probably not what you want. (If it IS what you want, put an & in front.)
(F) When trying to initialise the random seed for hashes, Perl could not get any randomness out of your system. This usually indicates Something Very Wrong.