9. Diagnostic Messages

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

Class	Meaning
(W)	A warning (optional)
(D)	A deprecation (optional)
(S)	A severe warning (mandatory)
(F)	A fatal error (trappable)
(P)	An internal error (panic) that you should never see (trappable)
(X)	A very fatal error (non-trappable)
(A)	An alien error message (not generated by Perl)

Optional warnings are enabled by using the -w switch. Warnings may be captured by setting $SIG{__WARN__} to a reference to a routine that will be called on each warning before printing it. Trappable errors may be trapped using eval. You can also capture control before a trappable error "dies" by setting $SIG{__DIE__} to a subroutine reference, but if you don't call die within that handler, the fatal exception is still thrown when you return from it. In other words, you're not allowed to "de-fatalize" an exception that way. You must use an eval wrapper for that.

In the following messages %s stands for an interpolated string that is determined only when the message is generated. (Similarly, %d stands for an interpolated number - think printf formats, but we use %d to mean a number in any base here.) Note that some messages begin with %s - which means that listing them alphabetically is problematical. You should search among these messages if the one you are looking for does not appear in the expected place. The symbols " % - ? @ sort before alphabetic characters, while [ and \ sort after.

References of the form, "See unpack," refer to entries in Chapter 3, Functions.

If you decide a bug is a Perl bug and not your bug, you should try to reduce it to a minimal test case and then report it with the perlbug program that comes with Perl.

"my" variable %s can't be in a package

(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.

"no" not allowed in expression

(F) The no keyword is recognized and executed at compile time, and returns no useful value.

"use" not allowed in expression

(F) The use keyword is recognized and executed at compile time, and returns no useful value.

% may only be used in unpack

(F) You can't pack a string by supplying a checksum, since the checksumming process loses information, and you can't go the other way. See unpack.

%s (...) interpreted as function

(W) You've run afoul of the rule that says that any list operator followed by parentheses turns into a function, with all the list operator's arguments found inside the parens. See the section "Terms and List Operators (Leftward)" in Chapter 2, The Gory Details.

%s argument is not a HASH element

(F) The argument to delete or exists must be a hash element, such as

$foo{$bar}
$ref->[12]->{"susie"}

%s did not return a true value

(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.

%s found where operator expected

(S) 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 had compilation errors.

(F) The final summary message when a perl -c command fails.

%s has too many errors.

(F) The parser has given up trying to parse the program after 10 errors. Further error messages would likely be uninformative.

%s matches null string many times

(W) The pattern you've specified would be an infinite loop if the regular expression engine didn't specifically check for that.

%s never introduced

(S) The symbol in question was declared but somehow went out of scope before it could possibly have been used.

%s syntax OK

(F) The final summary message when a perl -c command succeeds.

%s: Command not found.

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

%s: Expression syntax.

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

%s: Undefined variable.

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

%s: not found

(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.

-P not allowed for setuid/setgid script

(F) The script would have to be opened by the C preprocessor by name, which provides a race condition that breaks security.

-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.

500 Server error

See Server error.

?+* follows nothing in regexp

(F) You started a regular expression with a quantifier. Backslash it if you meant it literally.

@ outside of string

(F) You had a pack template that specified an absolute position outside the string being unpacked. See pack.

accept() on closed fd

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

Allocation too large: %d

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

Arg too short for msgsnd

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

Ambiguous use of %s resolved as %s

(W)(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, pair of parentheses, or declaration.

Args must match #! line

(F) The setuid emulator requires that the switches perl was invoked with match the switches specified on the #! line.

Argument "%s" isn't numeric

(W) 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.

Array @%s missing the @ in argument %d of %s()

(D) Really old Perl let you omit the @ on array names in some spots. This is now heavily deprecated.

assertion botched: %s

(P) The malloc(3) package that comes with Perl had an internal failure.

Assertion failed: file "%s"

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

Assignment to both a list and a scalar

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

Attempt to free non-arena SV: %d

(P) All SV objects are supposed to be allocated from arenas that will be garbage collected upon exit. An SV was discovered to be outside any of those arenas. This probably means that someone screwed up in a C extension module.

Attempt to free temp prematurely

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

Attempt to free unreferenced glob pointers

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

Attempt to free unreferenced scalar

(W) 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. In any event, it's likely a problem with the C extension module you're developing.

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

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

Bad associative array

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

Bad filehandle: %s

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

Bad free() ignored

(S) An internal routine called free(3) on something that had never been malloc(3)ed in the first place.

Bad name after %s::

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

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

is not the same as

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

Bad symbol for array

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

Bad symbol for filehandle

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

Bad symbol for hash

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

Badly placed ()'s

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

BEGIN failed--compilation aborted

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

bind() on closed fd

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

Bizarre copy of %s in %s

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

Callback called exit

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

Can't "last" outside a block

(F) A last statement was executed to break out of the current block, except that there's this itty bitty problem called there isn't a current block. See note on the next entry.

Can't "next" outside a block

(F) A next statement was executed to reiterate the current block, but there isn't a current block. Note that an if or else block doesn't count as a "loopish" block. You can usually double the curly brackets to get the same effect though, since the inner brackets will be considered a block that loops once. See last.

Can't "redo" outside a block

(F) A redo statement was executed to restart the current block, but there isn't a current block. See note on the previous entry.

Can't bless non-reference value

(F) Only hard references may be blessed. This is how Perl "enforces" encapsulation of objects.

Can't break at that line

(S) A debugger warning indicating the line number specified wasn't the location of a statement that could be stopped at.

Can't call method "%s" in empty package "%s"

(F) You called a method correctly, and it correctly indicated a package functioning as a class, but that package doesn't have anything at all defined in it, let alone methods.

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

(F) A method call must know what package it's supposed to run in. 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.

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

(F) You used the syntax of a method call, but the slot filled by the object reference or package name contains an expression that returns neither an object reference nor a package name. (Perhaps it's null?) Something like this will reproduce the error:

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

Can't chdir to %s

(F) You called perl -x/foo/bar, but /foo/bar is not a directory that you can chdir(2) to, possibly because it doesn't exist.

Can't coerce %s to integer in %s

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

*foo += 1;     # ERROR

You can say

$foo = *foo;   # make a "fake" glob value
$foo += 1;

but then $foo no longer contains a glob.

Can't coerce %s to number in %s

(F) Certain types of SVs, in particular real symbol table entries (type GLOB), can't be forced to stop being what they are. See preceding entry.

Can't coerce %s to string in %s

(F) Certain types of SVs, in particular real symbol table entries (type GLOB), can't be forced to stop being what they are. See previous two entries.

Can't create pipe mailbox

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

Can't declare %s in my

(F) Only scalar, array and hash variables may be declared as lexical variables. They must have ordinary identifiers as names, since lexical variables don't live in a symbol table, and can't be package qualified.

Can't do inplace edit on %s: %s

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

Can't do inplace edit without backup

(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 use the switch, -i.bak, or some such.

Can't do inplace edit: %s > 14 characters

(S) There isn't enough room in the filename to make a backup name for the file. Perhaps you should get a system with longer filenames. :-)

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

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

Can't do setegid!

(P) The setegid() call failed for some reason in the setuid emulator of suidperl.

Can't do seteuid!

(P) The setuid emulator of suidperl failed for some reason.

Can't do setuid

(F) This typically means that ordinary perl tried to exec suidperl to do setuid emulation, but couldn't exec it. If you're running /usr/local/bin/perl5.003, it looks for a corresponding /usr/local/bin/sperl5.003. (Note the "s".) If the file is there, check the execute permissions. If it isn't, ask your sysadmin why he and/or she removed it.

Can't do waitpid with flags

(F) This machine doesn't have either waitpid(2) or wait4(2), so only waitpid without flags is emulated.

Can't do {n,m} with n > m

(F) Minima must be less than or equal to maxima. If you really want your regular expression to match something 0 times, just put {0}.

Can't emulate -%s on #! line

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

Can't exec "%s": %s

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

Can't exec %s

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

Can't execute %s

(F) You used the -S switch, but the script to execute could not be found in the PATH, or at least not with the correct permissions.

Can't find label %s

(F) You said to goto a label that isn't mentioned anywhere that it's possible for us to go to. See goto.

Can't find string terminator %s anywhere before EOF

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

print q(The character '(' starts a s(n)ide comment.)

Can't fork

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

Can't get filespec - stale stat buffer?

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

Can't get pipe mailbox device name

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

Can't get SYSGEN parameter value for MAXBUF

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

Can't goto subroutine outside a subroutine

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

Can't localize a reference

(F) You said something like local $$ref, which is not allowed because the compiler can't determine whether $ref will end up pointing to anything with a symbol table entry, and a symbol table entry is necessary to do a local.

Can't localize lexical variable %s

(F) You used local on a variable name that was previous 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.

Can't locate %s in @INC

(F) You said to use (or require, or do) a file that couldn't be found in any of the libraries mentioned in @INC. Perhaps you need to set the PERL5LIB environment variable to say where the extra library is, or maybe the script needs to add the library name to @INC with the use lib directive. Or maybe you just misspelled the name of the file. See require.

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

(F) You called a method correctly, and it correctly indicated a package functioning as a class, but the package doesn't define that method name, nor do any of its base classes (which is why the message says "via" rather than "in").

Can't locate package %s for @%s::ISA

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

Can't mktemp()

(F) The mktemp routine failed for some reason while trying to process a -e switch. Maybe your /tmp partition is full, or clobbered.

Can't modify %s in %s

(F) You aren't allowed to assign to the item indicated, or otherwise try to change it, such as with an autoincrement.

Can't modify non-existent substring

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

Can't msgrcv to readonly var

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

Can't open %s: %s

(S) An inplace edit couldn't open the original file for the indicated reason. Usually this is because you don't have read permission for the file.

Can't open bidirectional pipe

(W) 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 Open2. Alternately, direct the pipe's output to a file using ">", and then read it in under a different filehandle.

Can't open error file %s as stderr

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

Can't open input file %s as stdin

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

Can't open output file %s as stdout

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

Can't open output pipe (name: %s)

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

Can't open perl script "%s": %s

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

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

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

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

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

Can't reswap uid and euid

(P) The setreuid call failed for some reason in the setuid emulator of suidperl.

Can't return outside a subroutine

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

Can't stat script "%s"

(P) For some reason you can't fstat(2) the script even though you have it open already. Bizarre.

Can't swap uid and euid

(P) The setreuid call failed for some reason in the setuid emulator of suidperl.

Can't take log of %d

(F) Logarithms are only defined on positive real numbers.

Can't take sqrt of %d

(F) For ordinary real numbers, you can't take the square root of a negative number. There's a Complex module available for Perl, though, if you really want to do that.

Can't undef active subroutine

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

Can't unshift

(F) You tried to unshift an "unreal" array that can't be unshifted, such as the main Perl stack.

Can't upgrade that kind of scalar

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

Can't upgrade to undef

(P) The undefined SV is the bottom of the totem pole, in the scheme of upgradability. Upgrading to undef indicates an error in the code calling sv_upgrade().

Can't use "my %s" in sort comparison

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

Can't use %s for loop variable

(F) Only a simple scalar variable may be used as a loop variable on a foreach.

Can't use %s ref as %s ref

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

Can't use \1 to mean $1 in expression

(W) 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 only valid as part of a regular expression pattern. Trying to do this in ordinary Perl code produces a value that prints out looking like SCALAR(0xdecaf). Use the $1 form instead.

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

(F) Only hard references are allowed by use strict refs. Symbolic references are disallowed.

Can't use an undefined value as %s reference

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

Can't use global %s in "my"

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

Can't use subscript on %s

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

Can't write to temp file for -e: %s

(F) The write(2) routine failed for some reason while trying to process a -e switch. Maybe your /tmp partition is full, or clobbered.

Can't x= to readonly value

(F) You tried to repeat a constant value (perhaps 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.

Cannot open temporary file

(F) The creat(2) routine failed for some reason while trying to process a -e switch. Maybe your /tmp partition is full, or clobbered.

chmod: mode argument is missing initial 0

(W) A novice will sometimes say

chmod 777, $filename

not realizing that 777 will be interpreted as a decimal number, equivalent to 01411. Octal constants are introduced with a leading 0 in Perl, as in C.

Close on unopened file %s

(W) You tried to close a filehandle that was never opened.

connect() on closed fd

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

Corrupt malloc ptr %d at %d

(P) The malloc(3) package that comes with Perl had an internal failure.

corrupted regexp pointers

(P) The regular expression engine got confused by what the regular expression compiler gave it.

corrupted regexp program

(P) The regular expression engine got passed a regular expression program without a valid magic number.

Deep recursion on subroutine "%s"

(W) This subroutine has called itself (directly or indirectly) 100 more times than it has returned. This probably indicates an infinite recursion, unless you're writing strange benchmark programs, in which case it indicates something else.

Did you mean &%s instead?

(W) You probably referred to an imported subroutine &FOO as $FOO or some such.

Did you mean $ or @ instead of %?

(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.

Do you need to predeclare %s?

(S) 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.

Don't know how to handle magic of type '%s'

(P) The internal handling of magical variables has been cursed.

do_study: out of memory

(P) This should have been caught by safemalloc() instead.

Duplicate free() ignored

(S) An internal routine has called free() on something that had already been freed.

elseif should be elsif

(S) 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 do what you want.

END failed--cleanup aborted

(F) An untrapped exception was raised while executing an END subroutine. The interpreter is immediately exited.

Error converting file specification %s

(F) An error peculiar to VMS. Since 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.

Execution of %s aborted due to compilation errors.

(F) The final summary message when a Perl compilation fails.

Exiting eval via %s

(W) You are exiting an eval by unconventional means, such as a goto, or a loop control statement.

Exiting subroutine via %s

(W) You are exiting a subroutine by unconventional means, such as a goto, or a loop control statement.

Exiting substitution via %s

(W) You are exiting a substitution by unconventional means, such as a return, a goto, or a loop control statement.

Fatal VMS error at %s, line %d

(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 %s and the line number in %d tell you which section of the Perl source code is distressed.

fcntl is not implemented

(F) Your machine apparently doesn't implement fcntl(2). What is this, a PDP-11 or something?

Filehandle %s never opened

(W) An I/O operation was attempted on a filehandle that was never initialized. You need to do an open or a socket call, or call a constructor from the FileHandle package.

Filehandle %s opened only for input

(W) 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 only intended to write the file, use > or >>. See open.

Filehandle only opened for input

Final $ should be \$ or $name

(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 add either the backslash or the name.

Final @ should be \@ or @name

(F) You must now decide whether the final @ in a string was meant to be a literal "at" sign, or was meant to introduce a variable name that happens to be missing. So you have to add either the backslash or the name.

Format %s redefined

(W) You redefined a format. To suppress this warning, say

{
    local $^W = 0;
    eval "format NAME =...";
}

Format not terminated

(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. If you think you have such a line, make sure there are no spaces or tabs on either side of the dot.

Found = in conditional, should be ==

(W) You said

if ($foo = 123)

when you meant

if ($foo == 123)

(or something like that).

gdbm store returned %d, errno %d, key "%s"

(S) A warning from the GDBM_File extension module that a store() failed.

gethostent not implemented

(F) Your C library apparently doesn't implement gethostent(3), probably because if it did, it'd feel morally obligated to return every hostname on the Internet. DNS tends to give machines a sense of grandeur.

get{sock,peer}name() on closed fd

(W) 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?

getpwnam returned invalid UIC %d for user "%s"

(S) A warning peculiar to VMS. The call to sys$getuai underlying the getpwnam function returned an invalid UIC.

Glob not terminated

(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 out some needed parentheses earlier in the line, and you really meant a "less than".

Global symbol "%s" requires explicit package name

(F) You've said use strict vars, which indicates that all variables must either be lexically scoped (using my), or explicitly qualified to say which package the global variable is in (using ::).

goto must have label

(F) Unlike next or last, you're not allowed to goto an unspecified destination, the opinions of Elizabethans nothwithstanding. Go to goto.

Had to create %s unexpectedly

(S) 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. This probably indicates a typo in an extension module.

Hash %%s missing the % in argument %d of %s()

(D) Really old Perl let you omit the % on hash names in some spots. This is now heavily deprecated.

Illegal division by zero

(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. Maybe both.

Illegal modulus zero

(F) You tried to divide a number by 0 to get the remainder. Most numbers don't take to this kindly.

Illegal octal digit

(F) You used an 8 or 9 in a octal number.

Illegal octal digit ignored

(W) You may have tried to use an 8 or 9 in a octal number. Interpretation of the octal number stopped before the 8 or 9.

Insecure dependency in %s

(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.

Insecure directory in %s

(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.

Insecure PATH

(F) You can't use system, exec, or a piped open in a setuid or setgid script if $ENV{PATH} is derived from data supplied (or potentially supplied) by the user. The script must set the path to a known value, using trustworthy data.

Internal inconsistency in tracking vforks

(S) A warning peculiar to VMS. Perl keeps track of the number of times you've called fork and exec, in order to determine whether the current call to exec should affect the current script or a subprocess (see exec). 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.

internal disaster in regexp

(P) Something went badly wrong in the regular expression parser.

internal urp in regexp at /%s/

(P) Something went badly awry in the regular expression parser.

invalid [] range in regexp

(F) The range specified in a character class had a minimum character greater than the maximum character.

ioctl is not implemented

(F) Your machine apparently doesn't implement ioctl(2), which is pretty strange for a machine that supports C.

junk on end of regexp

(P) The regular expression parser is confused.

Label not found for "last %s"

(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.

Label not found for "next %s"

(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.

Label not found for "redo %s"

(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.

listen() on closed fd

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

Literal @%s now requires backslash

(F) It used to be that Perl would try to guess whether you wanted an array interpolated or a literal @. It did this when the string was first used at run-time. Now strings are parsed at compile time, and ambiguous instances of @ must be disambiguated, either by putting a backslash to indicate a literal, or by declaring (or using) the array within the program before the string (lexically). (Someday it will simply assume that any unbackslashed @ interpolates an array.)

Method for operation %s not found in package %s during blessing

(F) An attempt was made to specify an entry in an overloading table that somehow doesn't point to a valid method.

Might be a runaway multi-line %s string starting on line %d

(S) This is an advisory indicating that the previously reported error may have been caused by a missing delimiter on a string or pattern, because it eventually ended earlier on the current line.

Misplaced _ in number

(W) An underline in a decimal constant wasn't on a three-digit boundary.

Missing $ on loop variable

(F) Apparently you've been programming in csh too much. Scalar variables are always introduced with a $ in Perl, unlike in the shells, where it can vary from one line to the next.

Missing comma after first argument to %s function

(F) While certain functions allow you to specify a filehandle or an "indirect object" before the argument list, this ain't one of 'em.

Missing operator before %s?

(S) This is an educated guess made in conjunction with the message "%s found where operator expected". Often the missing operator is a comma.

Missing right bracket

(F) The lexer counted more opening curly brackets (braces) than closing ones. Hint: you'll find the missing one near the place you were last editing.

Missing semicolon on previous line?

(S) 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.

Modification of a read-only value attempted

(F) You tried, directly or indirectly, to change the value of a constant. You didn't, of course, try 2 = 1, since the compiler catches that. But an easy way to do the same thing is:

sub mod { $_[0] = 1 }
mod(2);

Another way is to assign to a substr that's off the end of the string.

Modification of non-creatable array value attempted, subscript %d

(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.

Modification of non-creatable hash value attempted, subscript "%s"

(F) You tried to make a hash value spring into existence, and it couldn't be created for some peculiar reason.

Module name must be constant

(F) Only a bare module name is allowed as the first argument to a use. If you want to get fancier than that, call require within a BEGIN block.

msg%s not implemented

(F) You don't have System V message IPC on your system.

Multidimensional syntax %s not supported

(W) Multidimensional arrays aren't written like $foo[1,2,3]. They're written like $foo[1][2][3], as in C.

Negative length

(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.

nested *?+ in regexp

(F) You can't quantify a quantifier without intervening parens. So things like ** or +* or ?* are illegal, because you can't match things as many times as you want.

Note, however, that the minimal matching quantifiers, *?, +?, and ??, appear to be nested quantifiers, but aren't.

No #! line

(F) The setuid emulator requires that scripts have a well-formed #! line even on machines that don't support the #! construct.

No %s allowed while running setuid

(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.

No -e allowed in setuid scripts

(F) A setuid script can't be specified by the user.

No comma allowed after %s

(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.

No command into which to pipe on command line

(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 whither to pipe the output from this command.

No DB::DB routine defined

(F) The currently executing code was compiled with the -d switch, but for some reason the perl5db.pl file (or some facsimile thereof) didn't define a routine to be called at the beginning of each statement. Which is odd, because the file should have been required automatically, and should have blown up the require if it didn't parse right.

No dbm on this machine

(P) This is counted as an internal error, because every machine should supply dbm nowadays, since Perl comes with SDBM.

No DBsub routine

(F) The currently executing code was compiled with the -d switch, but for some reason the perl5db.pl file (or some facsimile thereof) didn't define a DB::sub routine to be called at the beginning of each ordinary subroutine call.

No error file after 2> or 2>> on command line

(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.

No input file after < on command line

(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.

No output file after > on command line

(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 whither you wanted to redirect STDOUT.

No output file after > or >> on command line

(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.

No Perl script found in input

(F) You called perl -x, but no line was found in the file beginning with #! and containing the word "perl".

No setregid available

(F) Configure didn't find anything resembling the setregid(2) call for your system.

No setreuid available

(F) Configure didn't find anything resembling the setreuid(2) call for your system.

No space allowed after -I

(F) The argument to -I must follow the -I immediately with no intervening space.

No such pipe open

(P) An error peculiar to VMS. The internal routine my_pclose() tried to close a pipe that hadn't been opened. This should have been caught earlier as an attempt to close an unopened filehandle.

No such signal: SIG%s

(W) 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.

Not a CODE reference

(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 reference it really was.

Not a format reference

(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.

Not a GLOB reference

(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 reference it really was.

Not a HASH reference

(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 reference it really was.

Not a perl script

(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".

Not a SCALAR reference

(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 reference it really was.

Not a subroutine reference

Not a subroutine reference in %OVERLOAD

(F) An attempt was made to specify an entry in an overloading table that somehow doesn't point to a valid subroutine.

Not an ARRAY reference

(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 reference it really was.

Not enough arguments for %s

(F) The function requires more arguments than you specified.

Not enough format arguments

(W) A format specified more picture fields than the subsequent values line supplied.

Null filename used

(F) You can't require the null filename, especially since on many machines that means the current directory! See require.

NULL OP IN RUN

(P) Some internal routine called run() with a null opcode pointer.

Null realloc

(P) An attempt was made to realloc(3) NULL.

NULL regexp argument

(P) The internal pattern-matching routines blew it bigtime.

NULL regexp parameter

(P) The internal pattern-matching routines are out of their gourd.

Odd number of elements in hash list

(S) You specified an odd number of elements to a hash list, which is odd, since hash lists come in key/value pairs.

oops: oopsAV

(S) An internal warning that the grammar is screwed up.

oops: oopsHV

(S) An internal warning that the grammar is screwed up.

Operation `%s' %s: no method found

(F) An attempt was made to use an entry in an overloading table that somehow no longer points to a valid method.

Operator or semicolon missing before %s

(S) 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 unlikely to be correct. For example, if you say *foo *foo it will be interpreted as if you said *foo * 'foo'.

Out of memory for yacc stack

(F) The byacc parser wanted to grow its stack so it could continue parsing, but realloc(3) wouldn't give it more memory, virtual or otherwise.

Out of memory!

(X) malloc(3) returned 0, indicating there was insufficient remaining memory (or virtual memory) to satisfy the request.

page overflow

(W) A single call to write produced more lines than can fit on a page.

panic: ck_grep

(P) Failed an internal consistency check trying to compile a grep.

panic: ck_split

(P) Failed an internal consistency check trying to compile a split.

panic: corrupt saved stack index

(P) The savestack was requested to restore more localized values than there are in the savestack.

panic: die %s

(P) We popped the context stack to an eval context, and then discovered it wasn't an eval context.

panic: do_match

(P) The internal pp_match() routine was called with invalid operational data.

panic: do_split

(P) Something terrible went wrong in setting up for the split.

panic: do_subst

(P) The internal pp_subst() routine was called with invalid operational data.

panic: do_trans

(P) The internal do_trans() routine was called with invalid operational data.

panic: goto

(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.

panic: INTERPCASEMOD

(P) The lexer got into a bad state at a character case modifier like \u.

panic: INTERPCONCAT

(P) The lexer got into a bad state parsing a string with brackets.

panic: last

(P) We popped the context stack to a block context, and then discovered it wasn't a block context.

panic: leave_scope clearsv

(P) A writable lexical variable became read-only somehow within the scope.

panic: leave_scope inconsistency

(P) The savestack probably got out of sync. At any rate, there was an invalid enum on the top of it.

panic: malloc

(P) Something requested a negative number of bytes of malloc(3).

panic: mapstart

(P) The compiler is screwed up with respect to the map function.

panic: null array

(P) One of the internal array routines was passed a null AV pointer.

panic: pad_alloc

(P) The compiler got confused about which scratchpad it was allocating and freeing temporaries and lexicals from.

panic: pad_free curpad

(P) The compiler got confused about which scratchpad it was allocating and freeing temporaries and lexicals from.

panic: pad_free po

(P) An invalid scratchpad offset was detected internally.

panic: pad_reset curpad

(P) The compiler got confused about which scratchpad it was allocating and freeing temporaries and lexicals from.

panic: pad_sv po

(P) An invalid scratchpad offset was detected internally.

panic: pad_swipe curpad

(P) The compiler got confused about which scratchpad it was allocating and freeing temporaries and lexicals from.

panic: pad_swipe po

(P) An invalid scratchpad offset was detected internally.

panic: pp_iter

(P) The foreach iterator got called in a non-loop context frame.

panic: realloc

(P) Something requested a negative number of bytes of realloc(3).

panic: restartop

(P) Some internal routine requested a goto (or something like it), and didn't supply the destination.

panic: return

(P) We popped the context stack to a subroutine or eval context, and then discovered it wasn't a subroutine or eval context.

panic: scan_num

(P) scan_num() got called on something that wasn't a number.

panic: sv_insert

(P) The sv_insert() routine was told to remove more string than there was string.

panic: top_env

(P) The compiler attempted to do a goto, or something weird like that.

panic: yylex

(P) The lexer got into a bad state while processing a character case modifier like \u.

Parens missing around "%s" list

(W) You said something like

my $foo, $bar = @_;

when you meant

my ($foo, $bar) = @_;

Remember that my and local bind closer than comma.

Perl %s required--this is only version %s, stopped

(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.

Permission denied

(F) The setuid emulator in suidperl decided you were up to no good.

pid %d not a child

(W) 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's perspective, it's probably not what you intended.

POSIX getpgrp can't take an argument

(F) Your C compiler uses POSIX getpgrp(2), which takes no argument, unlike the BSD version, which takes a pid.

Possible memory corruption: %s overflowed 3rd argument

(F) An ioctl(2) or fcntl(2) 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. You can try to trap this with eval, but remember your malloc arena may have been clobbered. Expect your program to dump core soon. If you're lucky, it won't set fire to the laser printer first. See ioctl.

Precedence problem: open %s should be open(%s)

(S) The old irregular construct

open FOO || die;

is now misinterpreted as

open(FOO || die);

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 parens around the filehandle, or use the new or operator instead of ||.

print on closed filehandle %s

(W) The filehandle you're printing on got itself closed sometime before now. Check your logic flow. It may have flowed away.

printf on closed filehandle %s

(W) The filehandle you're writing to got itself closed sometime before now. Check your logic flow. See previous joke.

Probable precedence problem on %s

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

open FOO || die;

Prototype mismatch: (%s) vs (%s)

(S) The subroutine being defined had a predeclared (forward) declaration with a different function prototype. The prototypes must match.

Read on closed filehandle <%s>

(W) The filehandle you're reading from got itself closed sometime before now. Check your logic flow. Don't see the previous joke.

Reallocation too large: %d

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

Recompile perl with -DDEBUGGING to use -D switch

(F) 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.

Recursive inheritance detected

(F) More than 100 levels of inheritance were used. Probably indicates an unintended loop in your inheritance hierarchy. Use -Do to trace object method lookups. (But see previous entry.)

Reference miscount in sv_replace()

(W) The internal sv_replace() function was handed a new SV with a reference count of other than 1.

regexp memory corruption

(P) The regular expression engine got confused by what the regular expression compiler gave it.

regexp out of space

(P) A "can't happen" error, because safemalloc() should have caught it earlier. If it didn't, your Perl is misconfigured.

regexp too big

(F) The current implementation of regular expression uses 16-bit shorts as address offsets within a string. Unfortunately this means that if the regular expression compiles to longer than 32767 bytes, it'll blow up. Usually when you want a regular expression this big, there is a better way to do it with multiple statements.

Reversed %s= operator

(W) You wrote your assignment operator backward. The = must always come last, to avoid ambiguity with subsequent unary operators.

Runaway format

(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).

Scalar value @%s[%s] better written as $%s[%s]

(W) You've used an array slice (indicated by @) to select a single value 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 only expecting 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, since Perl will not magically convert between scalars and lists for you.

Script is not setuid/setgid in suidperl

(F) Oddly, the suidperl program was invoked on a script with its setuid or setgid bit unset. This doesn't make much sense.

Search pattern not terminated

(F) The lexer couldn't find the final delimiter of a // or m{} construct. Remember that bracketing delimiters count nesting level.

seek() on unopened file

(W) You tried to use the seek function on a filehandle that was either never opened or has been closed since.

select not implemented

(F) This machine doesn't implement the select(2) system call.

sem%s not implemented

(F) You don't have System V semaphore IPC on your system.

semi-panic: attempt to dup freed string

(S) The internal newSVsv() routine was called to duplicate a scalar that had previously been marked as free.

Semicolon seems to be missing

(W) A nearby syntax error was probably caused by a missing semicolon, or possibly some other missing operator, such as a comma.

Send on closed socket

(W) The filehandle you're sending to got itself closed sometime before now. Check your logic flow.

Sequence (?#... not terminated

(F) A regular expression comment must be terminated by a closing parenthesis. Embedded parentheses aren't allowed. But with the /x modifier you can use an ordinary comment starting with #, which doesn't care.

Sequence (?%s...) not implemented

(F) A proposed regular expression extension has the character reserved but has not yet been written.

Sequence (?%s...) not recognized

(F) You used a regular expression extension that doesn't make sense.

Server error

(A) Also known as "500 Server error". 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.

setegid() not implemented

(F) You tried to assign to $), and your operating system doesn't support the setegid(2) system call (or equivalent), or at least Configure didn't think so.

seteuid() not implemented

(F) You tried to assign to $>, and your operating system doesn't support the seteuid(2) system call (or equivalent), or at least Configure didn't think so.

setrgid() not implemented

(F) You tried to assign to $(, and your operating system doesn't support the setrgid(2) system call (or equivalent), or at least Configure didn't think so.

setruid() not implemented

(F) You tried to assign to $<, and your operating system doesn't support the setruid(2) system call (or equivalent), or at least Configure didn't think so.

Setuid/gid script is writable by world

(F) The setuid emulator won't run a script that is writable by the world, because the world might have written on it already.

shm%s not implemented

(F) You don't have System V shared memory IPC on your system.

shutdown() on closed fd

(W) You tried to do a shutdown on a closed socket. Seems a bit superfluous.

SIG%s handler "%s" not defined.

(W) The signal handler named in %SIG doesn't, in fact, exist. Perhaps you put it into the wrong package?

sort is now a reserved word

(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.

Sort subroutine didn't return a numeric value

(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.

Sort subroutine didn't return single value

(F) A sort comparison subroutine may not return a list value with more or less than one element. See sort.

Split loop

(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.

Stat on unopened file %s

(W) You tried to use the stat function (or an equivalent file test) on a filehandle that was either never opened or has been closed since.

Statement unlikely to be reached

(W) 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. Or put a die after it.

Subroutine %s redefined

(W) You redefined a subroutine. To suppress this warning, say

{
    local $^W = 0;
    eval "sub name { ... }";
}

Substitution loop

(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 the section "Pattern-Matching Operators" in Chapter 2.

Substitution pattern not terminated

(F) The lexer couldn't find the interior delimiter of an s/// or s{}{} construct. Remember that bracketing delimiters count nesting level.

Substitution replacement not terminated

(F) The lexer couldn't find the final delimiter of an s/// or s{}{} construct. Remember that bracketing delimiters count nesting level.

substr outside of string

(W) 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.

suidperl is no longer needed since...

(F) Your perl was compiled with -DSETUID_SCRIPTS_ARE_SECURE_NOW, but a version of the setuid emulator somehow got run anyway.

syntax error

(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, since 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.

syntax error at line %d: `%s' unexpected

(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.

System V IPC is not implemented on this machine

(F) You tried to do something with a function beginning with sem, shm or msg. See semctl, for example.

Syswrite on closed filehandle

(W) The filehandle you're writing to got itself closed sometime before now. Check your logic flow. If you're tired of that, check someone else's.

tell() on unopened file

(W) You tried to use the tell function on a filehandle that was either never opened or has been closed since.

Test on unopened file %s

(W) You tried to invoke a file test operator on a filehandle that isn't open. Check your logic.

That use of $[ is unsupported

(F) Assignment to $[ is now strictly circumscribed, and interpreted as a compiler directive. You may only say one of

$[ = 0;
$[ = 1;
...
local $[ = 0;
local $[ = 1;
...

This is to prevent the problem of one module changing the array base out from under another module inadvertently. See the section on $[ in Chapter 2.

The %s function is unimplemented

(F) The function indicated isn't implemented on this architecture, according to the probings of Configure.

The crypt() function is unimplemented due to excessive paranoia.

(F) Configure couldn't find the crypt(3) 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 stat preceding -l _ wasn't an lstat

(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.

times not implemented

(F) Your version of the C library apparently doesn't do times(3). I suspect you're not running on UNIX.

Too few args to syscall

(F) There has to be at least one argument to syscall to specify the system call to call, silly dilly.

Too many ('s

Too many )'s

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

Too many args to syscall

(F) Perl supports a maximum of 14 args to syscall.

Too many arguments for %s

(F) The function requires fewer arguments than you specified.

trailing \ in regexp

(F) The regular expression ends with an unbackslashed backslash. Backslash it.

Translation pattern not terminated

(F) The lexer couldn't find the interior delimiter of a tr/// or tr[][] construct.

Translation replacement not terminated

(F) The lexer couldn't find the final delimiter of a tr/// or tr[][] construct.

truncate not implemented

(F) Your machine doesn't implement a file truncation mechanism that Configure knows about.

Type of arg %d to %s must be %s (not %s)

(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.

umask: argument is missing initial 0

(W) A umask of 222 is incorrect. It should be 0222, since octal literals always start with 0 in Perl, as in C.

Unable to create sub named "%s"

(F) You attempted to create or access a subroutine with an illegal name.

Unbalanced context: %d more PUSHes than POPs

(W) The exit code detected an internal inconsistency in how many execution contexts were entered and left.

Unbalanced saves: %d more saves than restores

(W) The exit code detected an internal inconsistency in how many values were temporarily localized.

Unbalanced scopes: %d more ENTERs than LEAVEs

(W) The exit code detected an internal inconsistency in how many blocks were entered and left.

Unbalanced tmps: %d more allocs than frees

(W) The exit code detected an internal inconsistency in how many mortal scalars were allocated and freed.

Undefined format "%s" called

(F) The format indicated doesn't seem to exist. Perhaps it's really in another package?

Undefined sort subroutine "%s" called

(F) The sort comparison routine specified doesn't seem to exist. Perhaps it's in a different package? See sort.

Undefined subroutine &%s called

(F) The subroutine indicated hasn't been defined, or if it was, it has since been undefined.

Undefined subroutine called

(F) The anonymous subroutine you're trying to call hasn't been defined, or if it was, it has since been undefined.

Undefined subroutine in sort

(F) The sort comparison routine specified is declared but doesn't seem to have been defined yet. See sort.

Undefined top format "%s" called

(F) The format indicated doesn't seem to exist. Perhaps it's really in another package?

unexec of %s into %s failed!

(F) The unexec() routine failed for some reason. See your local FSF representative, who probably put it there in the first place.

Unknown BYTEORDER

(F) There are no byteswapping functions for a machine with this byte order.

unmatched () in regexp

(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.

Unmatched right bracket

(F) The lexer counted more closing curly brackets (braces) than opening ones, so you're probably missing an opening bracket. As a general rule, you'll find the missing one (so to speak) near the place you were last editing.

unmatched [] in regexp

(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.

Unquoted string "%s" may clash with future reserved word

(W) 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.

Unrecognized character \%d ignored

(S) A garbage character was found in the input, and ignored, in case it's a weird control character on an EBCDIC machine, or some such.

Unrecognized signal name "%s"

(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.

Unrecognized switch: -%s

(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.)

Unsuccessful %s on filename containing newline

(W) A file operation was attempted on a filename, and that operation failed, probably because the filename contained a newline, probably because you forgot to chop or chomp it off. See chop.

Unsupported directory function "%s" called

(F) Your machine doesn't support opendir(3) and readdir(3).

Unsupported function %s

(F) This machine doesn't implement the indicated function, apparently. At least, Configure doesn't think so.

Unsupported socket function "%s" called

(F) Your machine doesn't support the Berkeley socket mechanism, or at least that's what Configure thought.

Unterminated <> operator

Use of $# is deprecated

(D) This was an ill-advised attempt to emulate a poorly defined awk feature. Use an explicit printf or sprintf instead.

Use of $* is deprecated

(D) This variable magically turned on multiline 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 $*.

Use of %s in printf format not supported

(F) You attempted to use a feature of printf that is accessible only from C. This usually means there's a better way to do it in Perl.

Use of %s is deprecated

(D) 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.

Use of bare << to mean <<"" is deprecated

(D) You are now encouraged to use the explicitly quoted form if you wish to use a blank line as the terminator of the here-document.

Use of implicit split to @_ is deprecated

(D) 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).

Use of uninitialized value

(W) 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 an initial value to your variables.

Useless use of %s in void context

(W) 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.

Variable "%s" is not exported

(F) While use strict in effect, you referred to a global variable that you 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.

Variable name "%s::%s" used only once: possible typo

(W) Typographical errors often show up as unique names. If you had a good reason for having a unique name, then just mention it again somehow to suppress the message. You might consider declaring the variable with use vars.

Variable syntax.

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

Warning: unable to close filehandle %s properly.

(S) The implicit close done by an open got an error indication on the close. This usually indicates your filesystem ran out of disk space.

Warning: Use of "%s" without parens is ambiguous

(S) 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.

Write on closed filehandle

(W) The filehandle you're writing to got itself closed sometime before now. Check your logic flow.

X outside of string

(F) You had a pack template that specified a relative position before the beginning of the string being unpacked. See pack.

x outside of string

(F) You had a pack template that specified a relative position after the end of the string being unpacked. See pack.

Xsub "%s" called in sort

(F) The use of an external subroutine as a sort comparison is not yet supported.

Xsub called in sort

(F) The use of an external subroutine as a sort comparison is not yet supported.

You can't use -l on a filehandle

(F) 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. Use a filename instead.

YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!

(F) And you probably never will, since 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 use the wrapsuid script in the eg/ directory to put a setuid C wrapper around your script.

You need to quote "%s"

(W) 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.)

[gs]etsockopt() on closed fd

(W) You tried to get or set a socket option on a closed socket. Did you forget to check the return value of your socket call? See getsockopt.

\1 better written as $1

(W) Outside of patterns, backreferences live on as variables. The use of backslashes is grandfathered on the righthand 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 nine backreferences.

'|' and '<' may not both be specified on command line

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

'|' and '>' may not both be specified on command line

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

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