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 access to 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
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 '}'.
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 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
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.
(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
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)
+
+If you actually want to pack Unicode codepoints, use the C<"U"> format
+instead.
+
+=item Character in "c" format wrapped
+
+(W pack) You said
-(W chmod) A novice will sometimes say
+ 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
"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
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
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.
-
=item Internal inconsistency in tracking vforks
(S) A warning peculiar to VMS. Perl keeps track of the number of times
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/
-
-(P) Something went badly awry in the regular expression parser. The <<<HERE
-shows in the regular expression about where the problem was discovered.
+=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.
=item %s (...) interpreted as function
(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>.
values cannot be returned in subroutines used in lvalue context. See
L<perlsub/"Lvalue subroutines">.
-=item Lookbehind longer than %d not implemented before << HERE %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
prefix1;prefix2
or
-
prefix1 prefix2
with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix of
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 "%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
(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 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").
some day, even though it doesn't yet. Perhaps you should use a
mixed-case attribute name, instead. See L<attributes>.
+=item Package '%s' not found (did you use the incorrect case?)
+
+(W misc) You included a package file via C<use>, but the package name
+did not match the file name. It's possible that you misspelled the
+package name.
+
=item page overflow
(W io) A single call to write() produced more lines than can fit on a
process which isn't a subprocess of the current process. While this is
fine from VMS' perspective, it's probably not what you intended.
-=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
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
{
(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 %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 ".."
(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
(W closed) The socket you're sending to got itself closed sometime
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 %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 %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 %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 << HE%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
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 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.
+
+=item Unknown switch condition (?(%.2s in regex;
-(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).
+marked by <-- HERE in m/%s/
-The << HERE shows in the regular expression about where the problem was
+(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 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 =~ /$pattern/) { ... }
+
+The <-- HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.
+
=item Useless use of %s in void context
(W void) You did something without a side effect in a context that does
throws away the left argument, which is not what you want. See
L<perlref> for more on this.
+This warning will not be issued for numerical constants equal to 0 or 1
+since they are often used in statements like
+
+ 1 while sub_with_side_effects() ;
+
+String constants that would normally evaluate to 0 or 1 are warned
+about.
+
=item Useless use of "re" pragma
(W) You did C<use re;> without any arguments. That isn't very useful.
+=item Useless use of %s with no values
+
+(W syntax) You used the push() or unshift() function with no arguments
+apart from the array, like C<push(@x)> or C<unshift(@foo)>. That won't
+usually have any effect on the array, so is completely useless. It's
+possible in principle that push(@tied_array) could have some effect
+if the array is tied to a class which implements a PUSH method. If so,
+you can write it as C<push(@tied_array,())> to avoid this warning.
+
=item "use" not allowed in expression
(F) The "use" keyword is recognized and executed at compile time, and
(D deprecated) You are now encouraged to use the explicitly quoted form
if you wish to use an empty line as the terminator of the here-document.
+=item Use of *glob{FILEHANDLE} is deprecated
+
+(D deprecated) You are now encouraged to use the shorter *glob{IO} form
+to access the filehandle slot within a typeglob.
+
+=item Use of chdir('') or chdir(undef) as chdir() deprecated
+
+(D deprecated) chdir() with no arguments is documented to change to
+$ENV{HOME} or $ENV{LOGDIR}. chdir(undef) and chdir('') share this
+behavior, but that has been deprecated. In future versions they
+will simply fail.
+
+Be careful to check that what you pass to chdir() is defined and not
+blank, else you might find yourself in your home directory.
+
=item Use of implicit split to @_ is deprecated
(D deprecated) It makes a lot of work for the compiler when you clobber
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.
+=item Use of "package" with no arguments is deprecated
+
+(D deprecated) You used the C<package> keyword without specifying a package
+name. So no namespace is current at all. Using this can cause many
+otherwise reasonable constructs to fail in baffling ways. C<use strict;>
+instead.
+
=item Use of %s in printf format not supported
(F) You attempted to use a feature of printf that is accessible from
(D deprecated) This was an ill-advised attempt to emulate a poorly
defined B<awk> feature. Use an explicit printf() or sprintf() instead.
-=item Use of reference "%s" in array index
+=item Use of reference "%s" as array index
(W) You tried to use a reference as an array index; this probably
-isn't what you mean, because references tend to be huge numbers which
-take you out of memory, and so usually indicates programmer error.
+isn't what you mean, because references in numerical context tend
+to be huge numbers, and so usually indicates programmer error.
If you really do mean it, explicitly numify your reference, like so:
-C<$array[0+$ref]>
+C<$array[0+$ref]>. This warning is not given for overloaded objects,
+either, because you can overload the numification and stringification
+operators and then you assumedly know what you are doing.
=item Use of reserved word "%s" is deprecated
the C<concatenation (.)> operator, even though there is no C<.> in your
program.
+=item Using a hash as a reference is deprecated
+
+(D deprecated) You tried to use a hash as a reference, as in
+C<< %foo->{"bar"} >> or C<< %$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 %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
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
=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
(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"
https://perl5.git.perl.org / perl5.git / blobdiff