(W syntax) You called stat() on an array, but the array will be
coerced to a scalar - the number of elements in the array.
+=item A signature parameter must start with '$', '@' or '%'
+
+(F) Each subroutine signature parameter declaration must start with a valid
+sigil; for example:
+
+ sub foo ($a, $, $b = 1, @c) {}
+
+=item A slurpy parameter may not have a default value
+
+(F) Only scalar subroutine signature parameters may have a default value;
+for example:
+
+ sub foo ($a = 1) {} # legal
+ sub foo (@a = (1)) {} # invalid
+ sub foo (%a = (a => b)) {} # invalid
+
=item assertion botched: %s
(X) The malloc package that comes with Perl had an internal failure.
=item Bareword in require contains "%s"
-=item Bareword in require maps to empty filename
-
=item Bareword in require maps to disallowed filename "%s"
+=item Bareword in require maps to empty filename
(F) The bareword form of require has been invoked with a filename which could
-not have been generated by a valid bareword permitted by the parser. You
+not have been generated by a valid bareword permitted by the parser. You
shouldn't be able to get this error from Perl code, but XS code may throw it
if it passes an invalid module name to C<Perl_load_module>.
=item Bareword in require must not start with a double-colon: "%s"
(F) In C<require Bare::Word>, the bareword is not allowed to start with a
-double-colon. Write C<require ::Foo::Bar> as C<require Foo::Bar> instead.
+double-colon. Write C<require ::Foo::Bar> as C<require Foo::Bar> instead.
=item Bareword "%s" not allowed while "strict subs" in use
(F) Some XS code tried to use C<sv_catpvfn()> or a related function with a
format string that specifies explicit indexes for some of the elements, and
-using a C-style variable-argument list (a C<va_list>). This is not currently
-supported. XS authors wanting to do this must instead construct a C array of
-C<SV*> scalars containing the arguments.
+using a C-style variable-argument list (a C<va_list>). This is not currently
+supported. XS authors wanting to do this must instead construct a C array
+of C<SV*> scalars containing the arguments.
=item Can only compress unsigned integers in pack
instead of Perl. Check the #! line, or manually feed your script into
Perl yourself. The #! line at the top of your file could look like
- #!/usr/bin/perl -w
+ #!/usr/bin/perl
+
+=item %s: command not found
+
+(A) You've accidentally run your script through B<bash> or another shell
+instead of Perl. Check the #! line, or manually feed your script into
+Perl yourself. The #! line at the top of your file could look like
+
+ #!/usr/bin/perl
+
+=item %s: command not found: %s
+
+(A) You've accidentally run your script through B<zsh> or another shell
+instead of Perl. Check the #! line, or manually feed your script into
+Perl yourself. The #! line at the top of your file could look like
+
+ #!/usr/bin/perl
=item Compilation failed in require
you have also specified an explicit size for the string. See
L<perlfunc/pack>.
+=item Declaring references is experimental
+
+(S experimental::declared_refs) This warning is emitted if you use
+a reference constructor on the right-hand side of C<my>, C<state>, C<our>, or
+C<local>. Simply suppress the warning if you want to use the feature, but
+know that in doing so you are taking the risk of using an experimental
+feature which may change or be removed in a future Perl version:
+
+ no warnings "experimental::declared_refs";
+ use feature "declared_refs";
+ $fooref = my \$foo;
+
=for comment
The following are used in lib/diagnostics.t for testing two =items that
share the same description. Changes here need to be propagated to there
described in L<perlunicode> and L<perlre>. You used C<\p> or C<\P> in
a regular expression without specifying the property name.
+=item ${^ENCODING} is no longer supported
+
+(D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
+the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
+
=item entering effective %s failed
(F) While under the C<use filetest> pragma, switching the real and
=item Hexadecimal float: exponent underflow
(W overflow) The hexadecimal floating point has a smaller exponent
-than the floating point supports.
+than the floating point supports. With the IEEE 754 floating point,
+this may also mean that the subnormals (formerly known as denormals)
+are being used, which may or may not be an error.
=item Hexadecimal float: internal error (%s)
=item Illegal character \%o (carriage return)
-(F) Perl normally treats carriage returns in the program text as it
-would any other whitespace, which means you should never see this error
-when Perl was built using standard options. For some reason, your
-version of Perl appears to have been built without this support. Talk
-to your Perl administrator.
+(F) Perl normally treats carriage returns in the program text as
+it would any other whitespace, which means you should never see
+this error when Perl was built using standard options. For some
+reason, your version of Perl appears to have been built without
+this support. Talk to your Perl administrator.
+
+=item Illegal character following sigil in a subroutine signature
+
+(F) A parameter in a subroutine signature contained an unexpected character
+following the C<$>, C<@> or C<%> sigil character. Normally the sigil
+should be followed by the variable name or C<=> etc. Perhaps you are
+trying use a prototype while in the scope of C<use feature 'signatures'>?
+For example:
+
+ sub foo ($$) {} # legal - a prototype
+
+ use feature 'signatures;
+ sub foo ($$) {} # illegal - was expecting a signature
+ sub foo ($a, $b)
+ :prototype($$) {} # legal
+
=item Illegal character in prototype for %s : %s
=item Initialization of state variables in list context currently forbidden
-(F) Currently the implementation of "state" only permits the
-initialization of scalar variables in scalar context. Re-write
-C<state ($a) = 42> as C<state $a = 42> to change from list to scalar
-context. Constructions such as C<state (@a) = foo()> will be
-supported in a future perl release.
+(F) C<state> only permits initializing a single scalar variable, in scalar
+context. So C<state $a = 42> is allowed, but not C<state ($a) = 42>. To apply
+state semantics to a hash or array, store a hash or array reference in a
+scalar variable.
=item %%s[%s] in scalar context better written as $%s[%s]
(W syntax) Multidimensional arrays aren't written like C<$foo[1,2,3]>.
They're written like C<$foo[1][2][3]>, as in C.
+=item Multiple slurpy parameters not allowed
+
+(F) In subroutine signatures, a slurpy parameter (C<@> or C<%>) must be
+the last parameter, and there must not be more than one of them; for
+example:
+
+ sub foo ($a, @b) {} # legal
+ sub foo ($a, @b, %) {} # invalid
+
=item '/' must follow a numeric type in unpack
(F) You had an unpack template that contained a '/', but this did not
reference to something else instead. You can use the ref() function to
find out what kind of ref it really was. See L<perlref>.
+=item '#' not allowed immediately following a sigil in a subroutine signature
+
+(F) In a subroutine signature definition, a comment following a sigil
+(C<$>, C<@> or C<%>), needs to be separated by whitespace or a commma etc., in
+particular to avoid confusion with the C<$#> variable. For example:
+
+ # bad
+ sub f ($# ignore first arg
+ , $b) {}
+ # good
+ sub f ($, # ignore first arg
+ $b) {}
+
=item Not an ARRAY reference
(F) Perl was trying to evaluate a reference to an array value, but found
for I/O (in anticipation of future reads and to imitate the behavior
with real files).
+=item Only one /x regex modifier is allowed
+
+=item Only one /x regex modifier is allowed in regex; marked by <-- HERE in m/%s/
+
+(F) You used the C</x> regular expression pattern modifier at least twice in a
+string of modifiers. This has been made illegal, in order to allow future
+extensions to the Perl language.
+
=item %s() on unopened %s
(W unopened) An I/O operation was attempted on a filehandle that was
(W unopened) You tried to invoke a file test operator on a filehandle
that isn't open. Check your control flow. See also L<perlfunc/-X>.
-=item Only one /x regex modifier is allowed
-
-=item Only one /x regex modifier is allowed in regex; marked by <-- HERE in m/%s/
-
-(F) You used the C</x> regular expression pattern modifier at least
-twice in a string of modifiers. It is illegal to do this with, to allow
-future extensions to the Perl language.
-
=item oops: oopsAV
(S internal) An internal warning that the grammar is screwed up.
thrown.
You are recommended to change your code to set C<$/> to C<undef> explicitly
-if you wish to slurp the file. In future versions of Perl assigning
+if you wish to slurp the file. In future versions of Perl assigning
a reference to will throw a fatal error.
=item Setting $/ to %s reference is forbidden
will continue to pretend that it is. And if you quote me on that, I
will deny it.
+=item The experimental declared_refs feature is not enabled
+
+(F) To declare references to variables, as in C<my \%x>, you must first enable
+the feature:
+
+ no warnings "experimental::declared_refs";
+ use feature "declared_refs";
+
=item The %s function is unimplemented
(F) The function indicated isn't implemented on this architecture,
=item Too few arguments for subroutine
-(F) A subroutine using a signature received fewer arguments than required
-by the signature. The caller of the subroutine is presumably at fault.
-Inconveniently, this error will be reported at the location of the
-subroutine, not that of the caller.
+(F) A subroutine using a signature received too few arguments than
+required by the signature. The caller of the subroutine is presumably
+at fault.
=item Too late for "-%s" option
=item Too many arguments for subroutine
-(F) A subroutine using a signature received more arguments than required
-by the signature. The caller of the subroutine is presumably at fault.
-Inconveniently, this error will be reported at the location of the
-subroutine, not that of the caller.
+(F) A subroutine using a signature received too many arguments than
+required by the signature. The caller of the subroutine is presumably
+at fault.
+
=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 Unescaped left brace in regex is illegal in regex;
+=item Unescaped left brace in regex is deprecated here, passed through in
+regex; marked by S<<-- HERE> in m/%s/
+
+(D deprecated, regexp) The simple rule to remember, if you want to
+match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
+regular expression pattern, is to escape each literal instance of it in
+some way. Generally easiest is to precede it with a backslash, like
+C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
+delimiters are also braces, any matching right brace (C<"}">) should
+also be escaped to avoid confusing the parser, for example,
+
+ qr{abc\{def\}ghi}
+
+Forcing literal C<"{"> characters to be escaped will enable the Perl
+language to be extended in various ways in future releases. To avoid
+needlessly breaking existing code, the restriction is is not enforced in
+contexts where there are unlikely to ever be extensions that could
+conflict with the use there of C<"{"> as a literal.
+
+In this release of Perl, some literal uses of C<"{"> are fatal, and some
+still just deprecated. This is because of an oversight: some uses of a
+literal C<"{"> that should have raised a deprecation warning starting in
+v5.20 did not warn until v5.26. By making the already-warned uses fatal
+now, some of the planned extensions can be made to the language sooner.
+
+The contexts where no warnings or errors are raised are:
+
+=over 4
+
+=item *
+
+as the first character in a pattern, or following C<"^"> indicating to
+anchor the match to the beginning of a line.
+
+=item *
+
+as the first character following a C<"|"> indicating alternation.
+
+=item *
+
+as the first character in a parenthesized grouping like
+
+ /foo({bar)/
+ /foo(?:{bar)/
+
+=item *
+
+as the first character following a quantifier
+
+ /\s*{/
+
+=back
+
+=for comment
+The text of the message above is duplicated below to allow splain (and
+'use diagnostics') to work. Since one is fatal, and one not, they can't
+be combined as one message. And since the non-fatal one is temporary,
+there's no real need to enhance perldiag to handle this transient case.
+
+=item Unescaped left brace in regex is illegal here in regex;
marked by S<<-- HERE> in m/%s/
-(F) You used a literal C<"{"> character in a regular
-expression pattern. You should change to use C<"\{"> or C<[{]> instead.
-If the pattern delimiters are also braces, any matching
-right brace (C<"}">) should also be escaped to avoid confusing the parser,
-for example,
+(F) The simple rule to remember, if you want to
+match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
+regular expression pattern, is to escape each literal instance of it in
+some way. Generally easiest is to precede it with a backslash, like
+C<"\{"> or enclose it in square brackets (C<"[{]">). If the pattern
+delimiters are also braces, any matching right brace (C<"}">) should
+also be escaped to avoid confusing the parser, for example,
- qr{abc\{def\}ghi}
+ qr{abc\{def\}ghi}
-This restriction is not enforced if the C<"{"> is the first character in
-the pattern; nor is a warning generated for this case, as there are no
-current plans to forbid it.
+Forcing literal C<"{"> characters to be escaped will enable the Perl
+language to be extended in various ways in future releases. To avoid
+needlessly breaking existing code, the restriction is is not enforced in
+contexts where there are unlikely to ever be extensions that could
+conflict with the use there of C<"{"> as a literal.
+
+In this release of Perl, some literal uses of C<"{"> are fatal, and some
+still just deprecated. This is because of an oversight: some uses of a
+literal C<"{"> that should have raised a deprecation warning starting in
+v5.20 did not warn until v5.26. By making the already-warned uses fatal
+now, some of the planned extensions can be made to the language sooner.
+
+The contexts where no warnings or errors are raised are:
+
+=over 4
+
+=item *
+
+as the first character in a pattern, or following C<"^"> indicating to
+anchor the match to the beginning of a line.
+
+=item *
+
+as the first character following a C<"|"> indicating alternation.
+
+=item *
+
+as the first character in a parenthesized grouping like
+
+ /foo({bar)/
+ /foo(?:{bar)/
+
+=item *
+
+as the first character following a quantifier
+
+ /\s*{/
+
+=back
=item unexec of %s into %s failed!
came from. If you really really know what you are doing you can turn
off this warning by C<no warnings 'surrogate';>.
-=item Unknown charname '' is deprecated
-
-(D deprecated) You had a C<\N{}> with nothing between the braces. This
-usage is deprecated, and will be made a syntax error in a future Perl
-version.
-
=item Unknown charname '%s'
(F) The name you used inside C<\N{}> is unknown to Perl. Check the
also happen if the C<\N{}> is not in the scope of the corresponding
C<S<use charnames>>.
+=item Unknown charname '' is deprecated
+
+(D deprecated) You had a C<\N{}> with nothing between the braces. This
+usage is deprecated, and will be made a syntax error in a future Perl
+version.
+
=item Unknown error
(P) Perl was about to print an error message in C<$@>, but the C<$@> variable
largest possible ones break the perl interpreter in some constructs,
including causing it to hang in a few cases. The known problem areas
are in C<tr///>, regular expression pattern matching using quantifiers,
-and as the upper limits in loops.
+as quote delimiters in C<qI<X>...I<X>> (where I<X> is the C<chr()> of a large
+code point), and as the upper limits in loops.
+There may be other breakages as well. If you get this warning, and
+things aren't working correctly, you probably have found one of these.
If your code is to run on various platforms, keep in mind that the upper
limit depends on the platform. It is much larger on 64-bit word sizes
(F) You used a verb pattern that is not allowed an argument. Remove the
argument or check that you are using the right verb.
-=item Version control conflict marker '%s'
+=item Version control conflict marker
(F) The parser found a line starting with C<E<lt><<<<<<>,
-C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
+C<E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>E<gt>>, or C<=======>. These may be left by a
version control system to mark conflicts after a failed merge operation.
=item Version number must be a constant number
Because various errors may only be detected by close() (e.g. buffering could
allow the C<print> in this example to return true even when the disk is full),
-it is dangerous to ignore its result. So when it happens implicitly, perl will
-signal errors by warning.
+it is dangerous to ignore its result. So when it happens implicitly, perl
+will signal errors by warning.
B<Prior to version 5.22.0, perl ignored such errors>, so the common idiom shown
above was liable to cause B<silent data loss>.
https://perl5.git.perl.org / perl5.git / blobdiff