+//depot/perl/pod/perldiag.pod#272 - edit change 14824 (text)
=head1 NAME
perldiag - various Perl diagnostics
must either both be scalars or both be lists. Otherwise Perl won't
know which context to supply to the right side.
-=item Negative offset to vec in lvalue context
+=item Attempt to access disallowed key '%s' in a fixed hash
-(F) When C<vec> is called in an lvalue context, the second argument must be
-greater than or equal to zero.
+(F) The failing code has attempted to get or set a key which is not in
+the current set of allowed keys of a fixed hash.
+
+=item Attempt to clear a fixed hash
+
+(F) It is currently not allowed to clear a fixed hash, even if the
+new hash would contain the same keys as before. This may change in
+the future.
+
+=item Attempt to delete readonly key '%s' from a fixed hash
+
+(F) The failing code attempted to delete a key whose value has been
+declared readonly from a fixed hash.
+
+=item Attempt to delete disallowed key '%s' from a fixed hash
+
+(F) The failing code attempted to delete from a fixed hash a key which
+is not in its key set.
=item Attempt to bless into a reference
=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"
=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<$ENV{PATH}>, the executable in question was compiled for another
checks for an undefined I<scalar> value. If you want to see if the hash
is empty, just use C<if (%hash) { # not empty }> for example.
+=item %s defines neither package nor VERSION--version check failed
+
+(F) You said something like "use Module 42" but in the Module file
+there are neither package declarations nor a C<$VERSION>.
+
=item Delimiter for here document is too long
(F) In a here document construct like C<<<FOO>, the label C<FOO> is too
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.
(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.
=item `%s' is not a code reference
-(W) The second (fourth, sixth, ...) argument of overload::constant needs
-to be a code reference. Either an anonymous subroutine, or a 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) You tried to overload a constant type the overload package is unaware of.
+(W overload) You tried to overload a constant type the overload package is
+unaware of.
=item junk on end of regexp
=item lstat() on filehandle %s
-(W io) You tried to do a lstat on a filehandle. What did you mean
+(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.)
appear if components are not found, or are too long. See
"PERLLIB_PREFIX" in L<perlos2>.
+=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.
(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
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 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.
+
=item Nested quantifiers in regex; marked by <-- HERE in m/%s/
(F) You can't quantify a quantifier without intervening parentheses. So
(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").
=item Odd number of arguments for overload::constant
-(W) The call to overload::constant contained an odd number of arguments.
-The arguments should come in pairs.
+(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
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
(P) We popped the context stack to an eval context, and then discovered
it wasn't an eval context.
-=item panic: pp_match
+=item panic: pp_match%s
(P) The internal pp_match() routine was called with invalid operational
data.
=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.
+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.
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 unsafe) The character class constructs [: :], [= =], and [. .] go
+(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
(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>.
+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
=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/
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 = $offset. See
+L<perlfunc/splice>.
+
=item Split loop
(P) The split was looping infinitely. (Obviously, a split shouldn't
(W redefine) You redefined a subroutine. To suppress this warning, say
{
- no warnings;
+ no warnings 'redefine';
eval "sub name { ... }";
}
=item Substitution pattern not terminated
-(F) The lexer couldn't find the interior delimiter of a s/// or s{}{}
+(F) The lexer couldn't find the interior delimiter of an s/// or s{}{}
construct. Remember that bracketing delimiters count nesting level.
Missing the leading C<$> 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.
=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 regex m/%s/
(F) The regular expression ends with an unbackslashed backslash.
(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
data Perl expected. Someone's very confused, or perhaps trying to
subvert Perl's population of %ENV for nefarious purposes.
+=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.
+
+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
(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 $x = sort @y;
+
+This is not very useful, and perl currently optimizes this away.
+
=item Useless use of %s with no values
(W syntax) You used the push() or unshift() function with no arguments
(D deprecated) You are now encouraged to use the shorter *glob{IO} form
to access the filehandle slot within a typeglob.
+=item Use of chdir('') or chdir(undef) as chdir() deprecated
+
+(D deprecated) chdir() with no arguments is documented to change to
+$ENV{HOME} or $ENV{LOGDIR}. chdir(undef) and chdir('') share this
+behavior, but that has been deprecated. In future versions they
+will simply fail.
+
+Be careful to check that what you pass to chdir() is defined and not
+blank, else you might find yourself in your home directory.
+
=item Use of implicit split to @_ is deprecated
(D deprecated) It makes a lot of work for the compiler when you clobber
you should remove AutoLoader from @ISA and change C<use AutoLoader;> to
C<use AutoLoader 'AUTOLOAD';>.
+=item Use of -l on filehandle %s
+
+(W io) A filehandle represents an opened file, and when you opened the file
+it already went past any symlink you are presumably trying to look for.
+The operation returned C<undef>. Use a filename instead.
+
=item Use of "package" with no arguments is deprecated
(D deprecated) You used the C<package> keyword without specifying a package
suppressed for subroutine names by either adding a C<&> prefix, or using
a package qualifier, e.g. C<&our()>, or C<Foo::our()>.
+=item Use of tainted arguments in %s is deprecated
+
+(W taint) You have supplied C<system()> or C<exec()> with multiple
+arguments and at least one of them is tainted. This used to be allowed
+but will become a fatal error in a future version of perl. Untaint your
+arguments. See L<perlsec>.
+
=item Use of uninitialized value%s
(W uninitialized) An undefined value was used as if it were already
=item Using a hash as a reference is deprecated
(D deprecated) You tried to use a hash as a reference, as in
-C<< %foo->{"bar"} >> or C<< %$ref->{"hello"} >>. Versions of perl <= 5.6.1
-used to allow this syntax, but shouldn't have. It is now deprecated, and will
+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
+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),
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
-(W utf8) 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. 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
(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 put a setuid C wrapper around
+about what you want. Your best bet is to put a setuid C wrapper around
your script.
=item You need to quote "%s"