+//depot/perl/pod/perldiag.pod#272 - edit change 14824 (text)
=head1 NAME
perldiag - various Perl diagnostics
(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 C<warnings> pragma.
+(W, D & S) can be controlled using the C<warnings> pragma.
If a message can be controlled by the C<warnings> pragma, its warning
category is included with the classification letter in the description
imported with the C<use subs> pragma).
To silently interpret it as the Perl operator, use the C<CORE::> prefix
-on the operator (e.g. C<CORE::log($x)>) or by declaring the subroutine
+on the operator (e.g. C<CORE::log($x)>) or declare the subroutine
to be an object method (see L<perlsub/"Subroutine Attributes"> or
L<attributes>).
+=item Ambiguous range in transliteration operator
+
+(F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
+all. To include a C<-> character in a transliteration, put it either
+first or last. (In the past, C<tr/a-z-0//> was synonymous with
+C<tr/a-y//>, which was probably not what you would have expected.)
+
=item Ambiguous use of %s resolved as %s
(W ambiguous)(S) You said something that may not be interpreted the way
=item Applying %s to %s will act on scalar(%s)
-(W misc) The pattern match (//), substitution (s///), and
-transliteration (tr///) operators work on scalar values. If you apply
+(W misc) The pattern match (C<//>), substitution (C<s///>), and
+transliteration (C<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
must either both be scalars or both be lists. Otherwise Perl won't
know which context to supply to the right side.
+=item Attempt to access key '%_' in fixed hash
+
+(F) A hash has been marked as READONLY at the C level to turn it
+into a "record" with a fixed set of keys. The failing code
+has attempted to get or set the value of a key which does not
+exist or to delete a key.
+
+=item Attempt to bless into a reference
+
+(F) The CLASSNAME argument to the bless() operator is expected to be
+the name of the package to bless the resulting object into. You've
+supplied instead a reference to something: perhaps you wrote
+
+ bless $self, $proto;
+
+when you intended
+
+ bless $self, ref($proto) || $proto;
+
+If you actually want to bless into the stringified version
+of the reference supplied, you need to stringify it yourself, for
+example by:
+
+ bless $self, "$proto";
+
=item Attempt to free non-arena SV: 0x%lx
(P internal) All SV objects are supposed to be allocated from arenas
used as an lvalue, which is pretty strange. Perhaps you forgot to
dereference it first. See L<perlfunc/substr>.
-=item Bad arg length for %s, is %d, should be %d
+=item Bad arg length for %s, is %d, should be %s
(F) You passed a buffer of the wrong size to one of msgctl(), semctl()
or shmctl(). In C parlance, the correct sizes are, respectively,
=item Bad evalled substitution pattern
-(F) You've used the /e switch to evaluate the replacement for a
+(F) You've used the C</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 '}'.
(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 C<PERL_BADFREE> to 1.
+setting environment variable C<PERL_BADFREE> to 0.
-This message can be quite often seen with DB_File on systems with "hard"
+This message can be seen quite often with DB_File on systems with "hard"
dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
which is left unnoticed if C<DB> uses I<forgiving> system malloc().
(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 L<perlfunc/bind>.
+=item binmode() on closed filehandle %s
+
+(W unopened) You tried binmode() on a filehandle that was never opened.
+Check you control flow and number of arguments.
+
=item Bit vector size > 32 non-portable
(W portable) Using bit vector sizes larger than 32 is non-portable.
=item Bizarre copy of %s in %s
(P) Perl detected an attempt to copy an internal value that is not
-copiable.
+copyable.
=item B<-P> not allowed for setuid/setgid script
(F) Only hard references may be blessed. This is how Perl "enforces"
encapsulation of objects. See L<perlobj>.
-=item Can't break at that line
-
-(S internal) A warning intended to only be printed while running within
-the debugger, indicating the line number specified wasn't the location
-of a statement that could be stopped at.
-
=item Can't call method "%s" in empty package "%s"
(F) You called a method correctly, and it correctly indicated a package
=item Can't declare class for non-scalar %s in "%s"
-(S) Currently, only scalar variables can 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) 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.
=item Can't declare %s in "%s"
characters and Perl was unable to create a unique filename during
inplace editing with the B<-i> switch. The file was ignored.
-=item Can't do {n,m} with n > m
+=item Can't do {n,m} with n > m in regex; marked by <-- HERE in m/%s/
-(F) Minima must be less than or equal to maxima. If you really want
-your regexp to match something 0 times, just put {0}. See L<perlre>.
+(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 L<perlre>.
=item Can't do setegid!
=item Can't exec "%s": %s
-(W exec) An system(), exec(), or piped open call could not execute the
+(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
C<$ENV{PATH}>, the executable in question was compiled for another
(F) A string of a form C<CORE::word> was given to prototype(), but there
is no builtin with the name C<word>.
+=item Can't find %s character property "%s"
+
+(F) You used C<\p{}> or C<\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 C<Is> or C<In> prefix?
+
=item Can't find label %s
(F) You said to goto a label that isn't mentioned anywhere that it's
unseen whitespace before or after your closing tag. A good programmer's
editor will have a way to help you find these characters.
+=item Can't find %s property definition %s
+
+(F) You may have tried to use C<\p> which means a Unicode property for
+example \p{Lu} is all uppercase letters. Escape the C<\p>, either
+C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, until
+possible C<\E>).
+
=item Can't fork
(F) A fatal error occurred while trying to fork while opening a
(F) You said something like C<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.
+that $ref will still be a reference.
=item Can't locate %s
redirection, and couldn't open the pipe into which to send data destined
for stdout.
-=item Can't open perl script "%s": %s
+=item Can't open perl script%s: %s
(F) The script you specified can't be opened for the indicated reason.
though, because the inner curlies will be considered a block that
loops once. See L<perlfunc/redo>.
-=item Can't remove %s: %s, skipping file
+=item Can't remove %s: %s, skipping file
(S inplace) You requested an inplace edit without creating a backup
file. Perl was unable to remove the original file to replace it with
temporary or readonly values) from a subroutine used as an lvalue. This
is not allowed.
+=item Can't return %s to lvalue scalar context
+
+(F) You tried to return a complete array or hash from an lvalue subroutine,
+but you called the subroutine in a way that made Perl think you meant
+to return only one value. You probably meant to write parentheses around
+the call to the subroutine, which tell Perl that the call should be in
+list context.
+
=item Can't return outside a subroutine
(F) The return statement was executed in mainline code, that is, where
(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.
+=item Can't use anonymous symbol table for method lookup
+
+(P) 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: C<undef %Some::Package::>.
+
=item Can't use bareword ("%s") as %s ref while "strict refs" in use
(F) Only hard references are allowed by "strict refs". Symbolic
references are disallowed. See L<perlref>.
-=item Can't use %%! because Errno.pm is not available
+=item Can't use %! because Errno.pm is not available
(F) The first time the %! hash is used, perl automatically loads the
Errno.pm module. The Errno module is expected to tie the %! hash to
with an assignment operator, which implies modifying the value itself.
Perhaps you need to copy the value to a temporary, and repeat that.
-=item Character class syntax [%s] belongs inside character classes
+=item Character in "C" format wrapped
-(W unsafe) The character class constructs [: :], [= =], and [. .] go
-I<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.
+(W pack) You said
-=item Character class syntax [. .] is reserved for future extensions
+ pack("C", $x)
-(W 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: "\[." and ".\]".
+where $x is either less than 0 or more than 255; the C<"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
-=item Character class syntax [= =] is reserved for future extensions
+ pack("C", $x & 255)
-(W 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: "\[=" and "=\]".
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
-=item Character class [:%s:] unknown
+=item Character in "c" format wrapped
-(F) The class in the character class [: :] syntax is unknown. See
-L<perlre>.
+(W pack) You said
-=item chmod() mode argument is missing initial 0
+ pack("c", $x)
-(W chmod) A novice will sometimes say
+where $x is either less than -128 or more than 127; the C<"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
- chmod 777, $filename
+ pack("c", $x & 255);
-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.
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
-=item Close on unopened file <%s>
+=item close() on unopened filehandle %s
(W unopened) You tried to close a filehandle that was never opened.
recursion and are not subject to a limit.) Try shortening the string
under examination; looping in Perl code (e.g. with C<while>) rather than
in the regular expression engine; or rewriting the regular expression so
-that it is simpler or backtracks less. (See L<perlbook> for information
+that it is simpler or backtracks less. (See L<perlfaq2> for information
on I<Mastering Regular Expressions>.)
=item connect() on closed socket %s
to check the return value of your socket() call? See
L<perlfunc/connect>.
-=item constant(%s): %s
+=item Constant(%s)%s: %s
(F) The parser found inconsistencies either while attempting to define
an overloaded constant, or when trying to find the character name
=item Copy method did not return a reference
-(F) The method which overloads "=" is buggy. See L<overload/Copy
-Constructor>.
+(F) The method which overloads "=" is buggy. See
+L<overload/Copy Constructor>.
=item CORE::%s is not a keyword
(D deprecated) defined() is not usually useful on arrays because it
checks for an undefined I<scalar> value. If you want to see if the
-array is empty, just use C<if (@array) { # not empty }> for example.
+array is empty, just use C<if (@array) { # not empty }> for example.
=item defined(%hash) is deprecated
(D deprecated) defined() is not usually useful on hashes because it
checks for an undefined I<scalar> value. If you want to see if the hash
-is empty, just use C<if (%hash) { # not empty }> for example.
+is empty, just use C<if (%hash) { # not empty }> for example.
+
+=item %s defines neither package nor VERSION--version check failed
+
+(F) You said something like "use Module 42" but in the Module file
+there are neither package declarations nor a C<$VERSION>.
=item Delimiter for here document is too long
See Server error.
+=item %s does not define %s::VERSION--version check failed
+
+(F) You said something like "use Module 42" but the Module did not
+define a C<$VERSION.>
+
=item Don't know how to handle magic of type '%s'
(P) The internal handling of magical variables has been cursed.
subroutine or package before the current location. You can use an empty
"sub foo;" or "package FOO;" to enter a "forward" declaration.
+=item dump() better written as CORE::dump()
+
+(W misc) You used the obsolescent C<dump()> built-in function, without fully
+qualifying it as C<CORE::dump()>. Maybe it's a typo. See L<perlfunc/dump>.
+
=item Duplicate free() ignored
(S malloc) An internal routine called free() on something that had
"elseif" for the class returned by the following block. This is
unlikely to be what you want.
+=item Empty %s
+
+(F) Empty C<\p{}> or C<\P{}>.
+
=item entering effective %s failed
(F) While under the C<use filetest> pragma, switching the real and
filenames, try using the glob() operator, or put the filenames into a
variable and glob that.
+=item exec? I'm not *that* kind of operating system
+
+(F) The C<exec> function is not implemented in MacPerl. See L<perlport>.
+
=item Execution of %s aborted due to compilation errors
(F) The final summary message when a Perl compilation fails.
END subroutine. Processing of the remainder of the queue of such
routines has been prematurely ended.
-=item false [] range "%s" in regexp
+=item False [] range "%s" in regex; marked by <-- HERE in m/%s/
(W regexp) A character class range must start and end at a literal
-character, not another character class like C<\d> or C<[:alpha:]>. The
-"-" in your false range is interpreted as a literal "-". Consider
-quoting the "-", "\-". See L<perlre>.
+character, not another character class like C<\d> or C<[: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 L<perlre>.
=item Fatal VMS error at %s, line %d
(F) Your machine apparently doesn't implement fcntl(). What is this, a
PDP-11 or something?
-=item Filehandle %s never opened
-
-(W unopened) 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.
-
=item Filehandle %s opened only for input
(W io) You tried to write on a read-only filehandle. If you intended it
=item flock() on closed filehandle %s
(W closed) The filehandle you're attempting to flock() got itself closed
-some time before now. Check your logic flow. flock() operates on
+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?
-=item ?+* follows nothing in regexp
+=item Quantifier follows nothing in regex;
+
+marked by <-- HERE in m/%s/
-(F) You started a regular expression with a quantifier. Backslash it if
-you meant it literally. See L<perlre>.
+(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 L<perlre>.
=item Format not terminated
(W redefine) You redefined a format. To suppress this warning, say
{
- no warnings;
+ no warnings 'redefine';
eval "format NAME =...";
}
(F) Unlike with "next" or "last", you're not allowed to goto an
unspecified destination. See L<perlfunc/goto>.
+=item %s-group starts with a count
+
+(F) In pack/unpack a ()-group started with a count. A count is
+supposed to follow something: a template character or a ()-group.
+
=item %s had compilation errors
(F) The final summary message when a C<perl -c> fails.
version of Perl appears to have been built without this support. Talk
to your Perl administrator.
+=item Illegal character in prototype for %s : %s
+
+(W syntax) An illegal character was found in a prototype declaration. Legal
+characters in prototypes are $, @, %, *, ;, [, ], &, and \.
+
=item Illegal division by zero
(F) You tried to divide a number by 0. Either something was wrong in
=item Illegal octal digit %s
-(F) You used an 8 or 9 in a octal number.
+(F) You used an 8 or 9 in an octal number.
=item Illegal octal digit %s ignored
-(W digit) You may have tried to use an 8 or 9 in a 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.
=item Illegal switch in PERL5OPT: %s
(X) The PERL5OPT environment variable may only be used to set the
-following switches: B<-[DIMUdmw]>.
+following switches: B<-[DIMUdmtw]>.
=item Ill-formed CRTL environ value "%s"
Failure of user callbacks dispatched using the C<G_KEEPERR> flag could
also result in this warning. See L<perlcall/G_KEEPERR>.
+=item In EBCDIC the v-string components cannot exceed 2147483647
+
+(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).
+
=item Insecure dependency in %s
(F) You tried to do something that the tainting mechanism didn't like.
potentially supplied) by the user. The script must set the path to a
known value, using trustworthy data. See L<perlsec>.
-=item In string, @%s now must be written as \@%s
-
-(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 runtime. Now strings are parsed at compile time, and
-ambiguous instances of @ must be disambiguated, either by prepending 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 an unbackslashed @ interpolates an array.)
-
=item Integer overflow in %s number
(W overflow) The hexadecimal, octal or binary number you have specified
internally--subject to loss of precision errors in subsequent
operations.
-=item internal disaster in regexp
+=item Internal disaster in regex; marked by <-- HERE in m/%s/
(P) Something went badly wrong in the regular expression parser.
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
=item Internal inconsistency in tracking vforks
Perl is making a guess and treating this C<exec> as a request to
terminate the Perl script and execute the specified command.
-=item internal urp in regexp at /%s/
+=item Internal urp in regex; marked by <-- HERE in m/%s/
-(P) Something went badly awry in the regular expression parser.
+(P) Something went badly awry in the regular expression parser. The
+<-- HERE shows in the regular expression about where the problem was
+discovered.
=item %s (...) interpreted as function
(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 L<perlop/Terms
-and List Operators (Leftward)>.
+operators arguments found inside the parentheses. See
+L<perlop/Terms and List Operators (Leftward)>.
=item Invalid %s attribute: %s
(W printf) Perl does not understand the given format conversion. See
L<perlfunc/sprintf>.
-=item invalid [] range "%s" in regexp
+=item Invalid [] range "%s" in regex; marked by <-- HERE in m/%s/
(F) The range specified in a character class had a minimum character
-greater than the maximum character. See L<perlre>.
+greater than the maximum character. One possibility is that you forgot the
+C<{}> from your ending C<\x{}> - C<\x> without the curly braces can go only
+up to C<ff>. The <-- HERE shows in the regular expression about where the
+problem was discovered. See L<perlre>.
+
+=item Invalid [] range "%s" in transliteration operator
+
+(F) The range specified in the tr/// or y/// operator had a minimum
+character greater than the maximum character. See L<perlop>.
=item Invalid separator character %s in attribute list
(F) Your machine apparently doesn't implement ioctl(), which is pretty
strange for a machine that supports C.
+=item ioctl() on unopened %s
+
+(W unopened) You tried ioctl() on a filehandle that was never opened.
+Check you control flow and number of arguments.
+
+=item IO::Socket::atmark not implemented on this architecture
+
+(F) Your machine doesn't implement the sockatmark() functionality,
+neither as a system call or an ioctl call (SIOCATMARK).
+
+=item `%s' is not a code reference
+
+(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.
+
+=item `%s' is not an overloadable type
+
+(W overload) You tried to overload a constant type the overload package is
+unaware of.
+
=item junk on end of regexp
(P) The regular expression parser is confused.
to check the return value of your socket() call? See
L<perlfunc/listen>.
+=item lstat() on filehandle %s
+
+(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.)
+
=item Lvalue subs returning %s not implemented yet
(F) Due to limitations in the current implementation, array and hash
values cannot be returned in subroutines used in lvalue context. See
L<perlsub/"Lvalue subroutines">.
+=item Lookbehind longer than %d not implemented in regex;
+
+marked by <-- HERE in m/%s/
+
+(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.
+
=item Malformed PERLLIB_PREFIX
(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 C<prefix1> is indeed a prefix of
appear if components are not found, or are too long. See
"PERLLIB_PREFIX" in L<perlos2>.
-=item %s matches null string many times
+=item Malformed prototype for %s: %s
+
+(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.
+
+=item Malformed UTF-8 character (%s)
+
+Perl detected something that didn't comply with UTF-8 encoding rules.
+
+=item Malformed UTF-16 surrogate
+
+Perl thought it was reading UTF-16 encoded character data but while
+doing it Perl met a malformed Unicode surrogate.
+
+=item %s matches null string many times in regex;
+
+marked by <-- HERE in m/%s/
(W regexp) The pattern you've specified would be an infinite loop if the
-regular expression engine didn't specifically check for that. See
-L<perlre>.
+regular expression engine didn't specifically check for that. The <-- HERE
+shows in the regular expression about where the problem was discovered.
+See L<perlre>.
+
+=item "%s" may clash with future reserved word
+
+(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".
=item % may only be used in unpack
=item Misplaced _ in number
-(W syntax) An underline in a decimal constant wasn't on a 3-digit boundary.
+(W syntax) An underscore (underbar) in a numeric constant did not
+separate two digits.
=item Missing %sbrace%s on \N{}
(S) This is an educated guess made in conjunction with the message "%s
found where operator expected". Often the missing operator is a comma.
+=item Missing right brace on %s
+
+(F) Missing right brace in C<\p{...}> or C<\P{...}>.
+
=item Missing right curly or square bracket
(F) The lexer counted more opening curly or square brackets than closing
Another way is to assign to a substr() that's off the end of the string.
+Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
+is aliased to a constant in the look I<LIST>:
+
+ $x = 1;
+ foreach my $n ($x, 2) {
+ $n *= 2; # modifies the $x, but fails on attempt to modify the 2
+ }
+
=item Modification of non-creatable array value attempted, %s
(F) You tried to make an array value spring into existence, and the
you omitted the name of the module. Consult L<perlrun> for full details
about C<-M> and C<-m>.
+=item More than one argument to open
+
+(F) The C<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 L<perlfunc/open> for details.
+
=item msg%s not implemented
(F) You don't have System V message IPC on your system.
(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.
-=item nested *?+ in regexp
+=item Negative offset to vec in lvalue context
+
+(F) When C<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.
+=item Nested quantifiers in regex; marked by <-- HERE in m/%s/
-Note, however, that the minimal matching quantifiers, C<*?>, C<+?>, and
+(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, C<*?>, C<+?>, and
C<??> appear to be nested quantifiers, but aren't. See L<perlre>.
=item %s never introduced
(F) The indicated command line switch needs a mandatory argument, but
you haven't specified one.
+=item No such class %s
+
+(F) You provided a class qualifier in a "my" or "our" declaration, but
+this class doesn't exist at this point in your program.
+
=item No such pipe open
(P) An error peculiar to VMS. The internal routine my_pclose() tried to
of Perl. Check the #! line, or manually feed your script into Perl
yourself.
+=item %s not allowed in length fields
+
+(F) The count in the (un)pack template may be replaced by C<[TEMPLATE]> only if
+C<TEMPLATE> always matches the same amount of packed bytes. Redesign
+the template.
+
=item no UTC offset information; assuming local time is UTC
(S) A warning peculiar to VMS. Perl was unable to find the local
=item Number too long
(F) Perl limits the representation of decimal numbers in programs to
-about about 250 characters. You've exceeded that length. Future
+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").
See also L<perlport> for writing portable code.
+=item Odd number of arguments for overload::constant
+
+(W overload) The call to overload::constant contained an odd number of
+arguments. The arguments should come in pairs.
+
+=item Odd number of elements in anonymous hash
+
+(W misc) You specified an odd number of elements to initialize a hash,
+which is odd, because hashes come in key/value pairs.
+
=item Odd number of elements in hash assignment
(W misc) You specified an odd number of elements to initialize a hash,
exception to this is that C<sysread()>ing past the buffer will extend
the buffer and zero pad the new area.
+=item -%s on unopened filehandle %s
+
+(W unopened) You tried to invoke a file test operator on a filehandle
+that isn't open. Check your control flow. See also L<perlfunc/-X>.
+
+=item %s() on unopened %s
+
+(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.
+
=item oops: oopsAV
(S internal) An internal warning that the grammar is screwed up.
depends on the way perl was compiled. By default it is not trappable.
However, if compiled for this, Perl may use the contents of C<$^M> as an
emergency pool after die()ing with this message. In this case the error
-is trappable I<once>.
+is trappable I<once>, and the error message will include the line and file
+where the failed request happened.
=item Out of memory during ridiculously large request
(P) We popped the context stack to an eval context, and then discovered
it wasn't an eval context.
-=item panic: do_match
+=item panic: pp_match%s
(P) The internal pp_match() routine was called with invalid operational
data.
-=item panic: do_split
-
-(P) Something terrible went wrong in setting up for the split.
-
=item panic: do_subst
(P) The internal pp_subst() routine was called with invalid operational
data.
-=item panic: do_trans
+=item panic: do_trans_%s
-(P) The internal do_trans() routine was called with invalid operational
+(P) The internal do_trans routines were called with invalid operational
data.
=item panic: frexp
(P) The foreach iterator got called in a non-loop context frame.
+=item panic: pp_split
+
+(P) Something terrible went wrong in setting up for the split.
+
=item panic: realloc
(P) Something requested a negative number of bytes of realloc.
(P) The lexer got into a bad state while processing a case modifier.
+=item panic: utf16_to_utf8: odd bytelen
+
+(P) Something tried to call utf16_to_utf8 with an odd (as opposed
+to even) byte length.
+
=item Parentheses missing around "%s" list
(W parenthesis) You said something like
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 system
-administrator have set up the so-called variable 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 L<perllocale> section B<LOCALE PROBLEMS>.
+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
+L<perllocale> section B<LOCALE PROBLEMS>.
+
+=item perlio: argument list not closed for layer "%s"
+
+(S) 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.
+
+=item perlio: invalid separator character %s in attribute list
+
+(S) 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.
+
+=item perlio: unknown layer "%s"
+
+(S) 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 C<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.
=item Permission denied
process which isn't a subprocess of the current process. While this is
fine from VMS' perspective, it's probably not what you intended.
+=item P must have an explicit size
+
+(F) The unpack format P must have an explicit size, not "*".
+
+=item POSIX syntax [%s] belongs inside character classes in regex;
+
+marked by <-- HERE in m/%s/
+
+(W regexp) The character class constructs [: :], [= =], and [. .] go
+I<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 L<perlre>.
+
+=item POSIX syntax [. .] is reserved for future extensions in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
+=item POSIX syntax [= =] is reserved for future extensions in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
+=item POSIX class [:%s:] unknown in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 B<not> have the C<is> prefix
+the corresponding C interfaces have: in other words, it's C<[[:print:]]>,
+not C<isprint>. See L<perlre>.
+
=item POSIX getpgrp can't take an argument
(F) Your system has POSIX getpgrp(), which takes no argument, unlike
end of the buffer just in case. This sentinel byte got clobbered, and
Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
+=item Possible unintended interpolation of %s in string
+
+(W ambiguous) You said something like `@foo' in a double-quoted string
+but there was no array C<@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.
+
=item Possible Y2K bug: %s
(W y2k) You are concatenating the number 19 with another number, which
=item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
-(W deprecated) You have written something like this:
+(D deprecated) You have written something like this:
sub doit
{
=item printf() on closed filehandle %s
(W closed) The filehandle you're writing to got itself closed sometime
-before now. Check your logic flow.
+before now. Check your control flow.
=item print() on closed filehandle %s
(W closed) The filehandle you're printing on got itself closed sometime
-before now. Check your logic flow.
+before now. Check your control flow.
=item Process terminated by SIG%s
=item Prototype mismatch: %s vs %s
-(S unsafe) The subroutine being declared or defined had previously been
+(S prototype) The subroutine being declared or defined had previously been
declared or defined with a different function prototype.
+=item Prototype not terminated
+
+(F) You've omitted the closing parenthesis in a function prototype
+definition.
+
+=item Quantifier in {,} bigger than %d in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
+=item Quantifier unexpected on zero-length expression;
+
+marked by <-- HERE in m/%s/
+
+(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
+C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
=item Range iterator outside integer range
(F) One (or both) of the numeric arguments to the range operator ".."
=item readline() on closed filehandle %s
(W closed) The filehandle you're reading from got itself closed sometime
-before now. Check your logic flow.
+before now. Check your control flow.
=item Reallocation too large: %lx
(W internal) The internal sv_replace() function was handed a new SV with
a reference count of other than 1.
+=item Reference to nonexistent group in regex;
+
+marked by <-- HERE in m/%s/
+
+(F) You used something like C<\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: C<\07>
+
+The <-- HERE shows in the regular expression about where the problem was
+discovered.
+
=item regexp memory corruption
(P) The regular expression engine got confused by what the regular
expression compiler gave it.
-=item regexp *+ operand could be empty
-
-(F) The part of the regexp subject to either the * or + quantifier could
-match an empty string.
-
-=item regexp out of space
+=item Regexp out of space
(P) A "can't happen" error, because safemalloc() should have caught it
earlier.
not magically convert between scalars and lists for you. See
L<perlref>.
+=item Scalars leaked: %d
+
+(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.
+
=item Script is not setuid/setgid in suidperl
(F) Oddly, the suidperl program was invoked on a script without a setuid
construct. Remember that bracketing delimiters count nesting level.
Missing the leading C<$> from a variable C<$m> may cause this error.
-=item %sseek() on unopened file
+=item %sseek() on unopened filehandle
(W unopened) You tried to use the seek() or sysseek() function on a
filehandle that was either never opened or has since been closed.
(F) This machine doesn't implement the select() system call.
+=item Self-ties of arrays and hashes are not supported
+
+(F) Self-ties are of arrays and hashes are not supported in
+the current implementation.
+
=item Semicolon seems to be missing
(W semicolon) A nearby syntax error was probably caused by a missing
=item send() on closed socket %s
(W closed) The socket you're sending to got itself closed sometime
-before now. Check your logic flow.
+before now. Check your control flow.
-=item Sequence (? incomplete
+=item Sequence (? incomplete in regex; marked by <-- HERE in m/%s/
-(F) A regular expression ended with an incomplete extension (?. See
+(F) A regular expression ended with an incomplete extension (?. The <-- HERE
+shows in the regular expression about where the problem was discovered. See
L<perlre>.
-=item Sequence (?%s...) not implemented
+=item Sequence (?{...}) not terminated or not {}-balanced in regex;
-(F) A proposed regular expression extension has the character reserved
-but has not yet been written. See L<perlre>.
+marked by <-- HERE in m/%s/
-=item Sequence (?%s...) not recognized
+(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
+L<perlre>.
-(F) You used a regular expression extension that doesn't make sense.
-See L<perlre>.
+=item Sequence (?%s...) not implemented in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
-=item Sequence (?#... not terminated
+=item Sequence (?%s...) not recognized in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
+=item Sequence (?#... not terminated in regex;
+
+marked by <-- HERE in m/%s/
(F) A regular expression comment must be terminated by a closing
-parenthesis. Embedded parentheses aren't allowed. See L<perlre>.
+parenthesis. Embedded parentheses aren't allowed. The <-- HERE shows in
+the regular expression about where the problem was discovered. See
+L<perlre>.
=item 500 Server error
location where the CGI server can't find it, basically, more or less.
Please see the following for more information:
- http://www.perl.com/CPAN/doc/FAQs/cgi/idiots-guide.html
- http://www.perl.com/CPAN/doc/FAQs/cgi/perl-cgi-faq.html
- ftp://rtfm.mit.edu/pub/usenet/news.answers/www/cgi-faq
- http://hoohoo.ncsa.uiuc.edu/cgi/interface.html
- http://www-genome.wi.mit.edu/WWW/faqs/www-security-faq.html
+ 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 L<perlfaq9>.
(F) A sort comparison subroutine may not return a list value with more
or less than one element. See L<perlfunc/sort>.
+=item splice() offset past end of array
+
+(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 = $offset. See
+L<perlfunc/splice>.
+
=item Split loop
(P) The split was looping infinitely. (Obviously, a split shouldn't
instead, which does return. To suppress this warning, put the exec() in
a block by itself.
-=item Stat on unopened file <%s>
-
-(W unopened) You tried to use the stat() function (or an equivalent file
-test) on a filehandle that was either never opened or has since been
-closed.
+=item stat() on unopened filehandle %s
-=item Strange *+?{} on zero-length expression
-
-(W regexp) You applied a regular expression quantifier in a place where
-it makes no sense, such as on a zero-width assertion. Try putting the
-quantifier inside the assertion instead. For example, the way to match
-"abc" provided that it is followed by three repetitions of "xyz" is
-C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+(W unopened) You tried to use the stat() function on a filehandle that
+was either never opened or has since been closed.
=item Stub found while resolving method `%s' overloading %s
(W redefine) You redefined a subroutine. To suppress this warning, say
{
- no warnings;
+ no warnings 'redefine';
eval "sub name { ... }";
}
=item Substitution pattern not terminated
-(F) The lexer couldn't find the interior delimiter of a s/// or s{}{}
+(F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
construct. Remember that bracketing delimiters count nesting level.
Missing the leading C<$> from variable C<$s> may cause this error.
=item Substitution replacement not terminated
-(F) The lexer couldn't find the final delimiter of a s/// or s{}{}
+(F) The lexer couldn't find the final delimiter of an s/// or s{}{}
construct. Remember that bracketing delimiters count nesting level.
Missing the leading C<$> from variable C<$s> may cause this error.
(F) Your Perl was compiled with B<-D>SETUID_SCRIPTS_ARE_SECURE_NOW, but
a version of the setuid emulator somehow got run anyway.
+=item Switch (?(condition)... contains too many branches in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 C<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 L<perlre>.
+
+=item Switch condition not recognized in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
=item switching effective %s is not implemented
(F) While under the C<use filetest> pragma, we cannot switch the real
of Perl. Check the #! line, or manually feed your script into Perl
yourself.
+=item syntax error in file %s at line %d, next 2 tokens "%s"
+
+(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".
+
=item %s syntax OK
(F) The final summary message when a C<perl -c> succeeds.
=item syswrite() on closed filehandle %s
(W closed) The filehandle you're writing to got itself closed sometime
-before now. Check your logic flow.
+before now. Check your control flow.
=item Target of goto is too deeply nested
(F) You tried to use C<goto> to reach a label that was too deeply nested
for Perl to reach. Perl is doing you a favor by refusing.
-=item tell() on unopened file
+=item tell() on unopened filehandle
(W unopened) You tried to use the tell() function on a filehandle that
was either never opened or has since been closed.
-=item Test on unopened file <%s>
-
-(W unopened) You tried to invoke a file test operator on a filehandle
-that isn't open. Check your logic. See also L<perlfunc/-X>.
-
=item That use of $[ is unsupported
(F) Assignment to C<$[> is now strictly circumscribed, and interpreted
The function indicated isn't implemented on this architecture, according
to the probings of Configure.
-=item The stat preceding C<-l _> wasn't an lstat
+=item The stat preceding %s 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
=item Too many )'s
+=item Too many ('s
+
(A) You've accidentally run your script through B<csh> instead of Perl.
Check the #! line, or manually feed your script into Perl yourself.
-=item Too many ('s
-
-=item trailing \ in regexp
+=item Trailing \ in regex m/%s/
(F) The regular expression ends with an unbackslashed backslash.
Backslash it. See L<perlre>.
%NAME or C<%{EXPR}>. No implicit dereferencing is allowed--use the
{EXPR} forms as an explicit dereference. See L<perlref>.
-=item umask: argument is missing initial 0
-
-(W umask) A umask of 222 is incorrect. It should be 0222, because octal
-literals always start with 0 in Perl, as in C.
-
=item umask not implemented
(F) Your machine doesn't implement the umask function and you tried to
(F) The unexec() routine failed for some reason. See your local FSF
representative, who probably put it there in the first place.
+=item Unicode character %s is illegal
+
+(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 C<no warnings 'utf8';>.
+
=item Unknown BYTEORDER
(F) There are no byte-swapping functions for a machine with this byte
order.
+=item Unknown "re" subpragma '%s' (known ones are: %s)
+
+You tried to use an unknown subpragma of the "re" pragma.
+
+=item Unknown switch condition (?(%.2s in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
=item Unknown open() mode '%s'
(F) The second argument of 3-argument open() is not among the list
data Perl expected. Someone's very confused, or perhaps trying to
subvert Perl's population of %ENV for nefarious purposes.
-=item unmatched [] in regexp
+=item Unknown warnings category '%s'
+
+(F) An error issued by the C<warnings> pragma. You specified a warnings
+category that is unknown to perl at this point.
-(F) The brackets around a character class must match. If you wish to
+Note that if you want to enable a warnings category registered by a module
+(e.g. C<use warnings 'File::Find'>), you must have imported this module
+first.
+
+=item unmatched [ in regex; marked by <-- HERE in m/%s/
+
+(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. See L<perlre>.
+first. The <-- HERE shows in the regular expression about where the problem
+was discovered. See L<perlre>.
-=item unmatched () in regexp
+=item unmatched ( in regex; marked by <-- HERE in m/%s/
(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. See L<perlre>.
+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 L<perlre>.
=item Unmatched right %s bracket
recognized by Perl inside character classes. The character was
understood literally.
-=item /%s/: Unrecognized escape \\%c passed through
+=item Unrecognized escape \\%c passed through in regex;
+
+marked by <-- HERE in m/%s/
(W regexp) You used a backslash-character combination which is not
-recognized by Perl. This combination appears in an interpolated
-variable or a C<'>-delimited regular expression. The character was
-understood literally.
+recognized by Perl. This combination appears in an interpolated variable or
+a C<'>-delimited regular expression. The character was understood
+literally. The <-- HERE shows in the regular expression about where the
+escape was discovered.
=item Unrecognized escape \\%c passed through
(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 chop() or chomp() it off. See
-L<perlfunc/chomp>.
+PROBABLY because you forgot to chomp() it off. See L<perlfunc/chomp>.
=item Unsupported directory function "%s" called
(W untie) A copy of the object returned from C<tie> (or C<tied>) was
still valid when C<untie> was called.
+=item Useless (?%s) - use /%s modifier in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
+=item Useless (?-%s) - don't use /%s modifier in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
=item Useless use of %s in void context
(W void) You did something without a side effect in a context that does
throws away the left argument, which is not what you want. See
L<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.
+
=item Useless use of "re" pragma
(W) You did C<use re;> without any arguments. That isn't very useful.
+=item Useless use of sort in scalar context
+
+(W void) You used sort in scalar context, as in :
+
+ my $x = sort @y;
+
+This is not very useful, and perl currently optimizes this away.
+
+=item Useless use of %s with no values
+
+(W syntax) You used the push() or unshift() function with no arguments
+apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
+usually have any effect on the array, so is completely useless. It's
+possible in principle that push(@tied_array) could have some effect
+if the array is tied to a class which implements a PUSH method. If so,
+you can write it as C<push(@tied_array,())> to avoid this warning.
+
=item "use" not allowed in expression
(F) The "use" keyword is recognized and executed at compile time, and
(D deprecated) You are now encouraged to use the explicitly quoted form
if you wish to use an empty line as the terminator of the here-document.
+=item Use of *glob{FILEHANDLE} is deprecated
+
+(D deprecated) You are now encouraged to use the shorter *glob{IO} form
+to access the filehandle slot within a typeglob.
+
+=item Use of chdir('') or chdir(undef) as chdir() deprecated
+
+(D deprecated) chdir() with no arguments is documented to change to
+$ENV{HOME} or $ENV{LOGDIR}. chdir(undef) and chdir('') share this
+behavior, but that has been deprecated. In future versions they
+will simply fail.
+
+Be careful to check that what you pass to chdir() is defined and not
+blank, else you might find yourself in your home directory.
+
=item Use of implicit split to @_ is deprecated
(D deprecated) It makes a lot of work for the compiler when you clobber
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.
+=item Use of -l on filehandle %s
+
+(W io) A filehandle represents an opened file, and when you opened the file
+it already went past any symlink you are presumably trying to look for.
+The operation returned C<undef>. Use a filename instead.
+
+=item Use of "package" with no arguments is deprecated
+
+(D deprecated) You used the C<package> keyword without specifying a package
+name. So no namespace is current at all. Using this can cause many
+otherwise reasonable constructs to fail in baffling ways. C<use strict;>
+instead.
+
=item Use of %s in printf format not supported
(F) You attempted to use a feature of printf that is accessible from
(D deprecated) This was an ill-advised attempt to emulate a poorly
defined B<awk> feature. Use an explicit printf() or sprintf() instead.
+=item Use of reference "%s" as array index
+
+(W) You tried to use a reference as an array index; this probably
+isn't what you mean, because references in numerical context tend
+to be huge numbers, and so usually indicates programmer error.
+
+If you really do mean it, explicitly numify your reference, like so:
+C<$array[0+$ref]>. This warning is not given for overloaded objects,
+either, because you can overload the numification and stringification
+operators and then you assumedly know what you are doing.
+
=item Use of reserved word "%s" is deprecated
(D deprecated) The indicated bareword is a reserved word. Future
suppressed for subroutine names by either adding a C<&> prefix, or using
a package qualifier, e.g. C<&our()>, or C<Foo::our()>.
+=item Use of tainted arguments in %s is deprecated
+
+(W taint) You have supplied C<system()> or C<exec()> with multiple
+arguments and at least one of them is tainted. This used to be allowed
+but will become a fatal error in a future version of perl. Untaint your
+arguments. See L<perlsec>.
+
=item Use of uninitialized value%s
(W uninitialized) An undefined value was used as if it were already
the C<concatenation (.)> operator, even though there is no C<.> in your
program.
+=item Using a hash as a reference is deprecated
+
+(D deprecated) You tried to use a hash as a reference, as in
+C<< %foo->{"bar"} >> or C<< %$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.
+
+=item Using an array as a reference is deprecated
+
+(D deprecated) You tried to use an array as a reference, as in
+C<< @foo->[23] >> or C<< @$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.
+
+=item UTF-16 surrogate %s
+
+(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 C<no warnings 'utf8';>.
+
=item Value of %s can be "0"; test with defined()
(W misc) In a conditional expression, you used <HANDLE>, <*> (glob),
reference variables in outer subroutines are called or referenced, they
are automatically rebound to the current values of such variables.
+=item Variable length lookbehind not implemented in regex;
+
+marked by <-- HERE in m/%s/
+
+(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 L<perlre>.
+
=item Version number must be a constant number
(P) The attempt to translate a C<use Module n.n LIST> statement into
its equivalent C<BEGIN> block found an internal inconsistency with
the version number.
+=item v-string in use/require is non-portable
+
+(W) The use of v-strings is non-portable to older, pre-5.6, Perls.
+If you want your scripts to be backward portable, use the floating
+point version number: for example, instead of C<use 5.6.1> say
+C<use 5.006_001>. This of course won't help: the older Perls
+won't suddenly start understanding newer features, but at least
+they will show a sensible error message indicating the required
+minimum version.
+
=item Warning: something's wrong
(W) You passed warn() an empty string (the equivalent of C<warn "">) or
So put in parentheses to say what you really mean.
+=item Wide character in %s
+
+(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) but can be
+turned off by C<no warnings 'utf8';>. You are supposed to explicitly
+mark the filehandle with an encoding, see L<open> and L<perlfunc/binmode>.
+
=item write() on closed filehandle %s
(W closed) The filehandle you're writing to got itself closed sometime
-before now. Check your logic flow.
+before now. Check your control flow.
=item X outside of string
(F) The use of an external subroutine as a sort comparison is not yet
supported.
-=item You can't use C<-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.
-
=item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!
(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 use the wrapsuid script in the
-eg directory to put a setuid C wrapper around your script.
+about what you want. Your best bet is to put a setuid C wrapper around
+your script.
=item You need to quote "%s"
projects / p5sagit/p5-mst-13.2.git / blobdiff