(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 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
=item Negative offset to vec in lvalue context
-(F) When vec is called in an lvalue context, the second argument must be
+(F) When C<vec> is called in an lvalue context, the second argument must be
greater than or equal to zero.
=item Attempt to bless into a reference
=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 '}'.
(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.
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 before << HERE in regex m/%s/
+=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}. The << HERE shows in the
+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!
(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 find. Maybe you mispelled 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 chmod() mode argument is missing initial 0
+=item Character in "C" format wrapped
+
+(W pack) You said
+
+ pack("C", $x)
+
+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
+
+ pack("C", $x & 255)
-(W chmod) A novice will sometimes say
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
+
+=item Character in "c" format wrapped
+
+(W pack) You said
+
+ pack("c", $x)
- chmod 777, $filename
+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
-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.
+ pack("c", $x & 255);
+
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
=item close() on unopened filehandle %s
=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 Delimiter for here document is too long
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
=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 Quantifier follows nothing before << HERE in regex m/%s/
+=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. The << HERE shows in the regular expression about where the
-problem was discovered. See L<perlre>.
+meant it literally. The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
=item Format not terminated
internally--subject to loss of precision errors in subsequent
operations.
-=item Internal disaster before << HERE in regex m/%s/
+=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
+The <-- HERE shows in the regular expression about where the problem was
discovered.
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 before << HERE in regex m/%s/
+=item Internal urp in regex; marked by <-- HERE in m/%s/
-(P) Something went badly awry in the regular expression parser. The <<<HERE
-shows in the regular expression about where the problem was discovered.
+(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
+=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>.
(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) The second (fourth, sixth, ...) argument of overload::constant needs
values cannot be returned in subroutines used in lvalue context. See
L<perlsub/"Lvalue subroutines">.
-=item Lookbehind longer than %d not implemented before << HERE in reges m/%s/
+=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.
+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
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
+=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 % 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{}
$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 do a read/write/send/recv operation with a buffer
length that is less than 0. This is difficult to imagine.
-=item Nested quantifiers before << HERE in regex m/%s/
+=item Nested quantifiers in regex; marked by <-- HERE in m/%s/
(F) You can't quantify a quantifier without intervening parentheses. So
-things like ** or +* or ?* are illegal. The << HERE shows in the regular
+things like ** or +* or ?* are illegal. The <-- HERE shows in the regular
expression about where the problem was discovered.
-Note, however, that the minimal matching quantifiers, C<*?>, C<+?>, and
+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
(S internal) The symbol in question was declared but somehow went out of
=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 logic. See also L<perlfunc/-X>.
+that isn't open. Check your control flow. See also L<perlfunc/-X>.
-=item %s() on unopened %s %s
+=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()
(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
(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.
=item panic: utf16_to_utf8: odd bytelen
(P) Something tried to call utf16_to_utf8 with an odd (as opposed
-to even) byte length.
+to even) byte length.
=item Parentheses missing around "%s" list
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 an 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
(F) The setuid emulator in suidperl decided you were up to no good.
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 POSIX syntax [%s] belongs inside character classes
+=item POSIX syntax [%s] belongs inside character classes in regex;
+
+marked by <-- HERE in m/%s/
(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 and will cause fatal errors.
+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;
-=item POSIX syntax [. .] is reserved for future extensions
+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: "\[." and ".\]".
+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
+=item POSIX syntax [= =] is reserved for future extensions in regex;
-(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: "\[=" and "=\]".
+marked by <-- HERE in m/%s/
-=item POSIX class [:%s:] unknown
+(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>.
-(F) The class in the character class [: :] syntax is unknown. 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.
+See L<perlre>.
=item POSIX getpgrp can't take an argument
=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
(S unsafe) The subroutine being declared or defined had previously been
declared or defined with a different function prototype.
-=item Quantifier in {,} bigger than %d before << HERE in regex m/%s/
+=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
+{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 before << HERE in regex m/%s/
+=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
"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 before << HERE in regex m/%s/
+=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
+The <-- HERE shows in the regular expression about where the problem was
discovered.
=item regexp memory corruption
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
=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 before << HERE mark in regex m/%s/
+=item Sequence (? incomplete in regex; marked by <-- HERE in m/%s/
-(F) A regular expression ended with an incomplete extension (?. The <<<HERE
+(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 (?{...}) not terminated or not {}-balanced in regex m/%s/
+=item Sequence (?{...}) not terminated or not {}-balanced in regex;
+
+marked by <-- HERE in m/%s/
(F) If the contents of a (?{...}) clause contains braces, they must balance
-for Perl to properly detect the end of the clause. See L<perlre>.
+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>.
-=item Sequence (?%s...) not implemented before << HERE mark in regex m/%s/
+=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
+has not yet been written. The <-- HERE shows in the regular expression about
where the problem was discovered. See L<perlre>.
-=item Sequence (?%s...) not recognized before << HERE mark in regex m/%s/
+=item Sequence (?%s...) not recognized in regex;
-(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>.
+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 m/%s/
+=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
(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 before << HERE in regex m/%s/
+=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
(?(condition)(?:this|that|other)|else-clause)
-The << HERE shows in the regular expression about where the problem was
+The <-- HERE shows in the regular expression about where the problem was
discovered. See L<perlre>.
-=item Switch condition not recognized before << HERE in regex m/%s/
+=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
+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
=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
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 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) There are no byte-swapping functions for a machine with this byte
order.
-=item Unknown switch condition (?(%.2s before << HERE in regex m/%s/
+=item Unknown "re" subpragma '%s' (known ones are: %s)
+
+You tried to use an unknown subpragma of the "re" pragma.
-(F) The condition of a (?(condition)if-clause|else-clause) construct is not
-known. The condition may be lookaround (the condition is true if the
-lookaround 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 is defined).
+=item Unknown switch condition (?(%.2s in regex;
-The << HERE shows in the regular expression about where the problem was
+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'
data Perl expected. Someone's very confused, or perhaps trying to
subvert Perl's population of %ENV for nefarious purposes.
-=item unmatched [ before << HERE mark in regex m/%s/
+=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>. The << HERE shows in the regular expression about
-where the escape was discovered.
+first. The <-- HERE shows in the regular expression about where the problem
+was discovered. See L<perlre>.
-=item unmatched ( in regexp before << HERE mark in regex m/%s/
+=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 Unrecognized escape \\%c passed through before << HERE in m/%s/
+=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. The << HERE shows in the regular expression about where the escape
-was discovered.
-
+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 %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
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.
+=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
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 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 before << HERE in regex m/%s/
+=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.
+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
=item Wide character in %s
-(F) Perl met a wide character (>255) when it wasn't expecting one.
+(W utf8) Perl met a wide character (>255) when it wasn't expecting one.
=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) 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"