Re: [ID 20001130.011] expression parsing bug ?

[perl5.git] / pod / perldiag.pod

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index a754daa..830faab 100644 (file)
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -59,6 +59,17 @@ L<perlfunc/accept>.
 (F) The '!' is allowed in pack() and unpack() only after certain types.
 See L<perlfunc/pack>.
 
 (F) The '!' is allowed in pack() and unpack() only after certain types.
 See L<perlfunc/pack>.
 

+=item Ambiguous -%c() resolved as a file test
+
+(W ambiguous) You used a "-" right in front a call to a subroutine
+that has the same name as a Perl file test (C<r w x o R W X O e z s
+f d l p S u g k b c t T B M A C>).
+
+To disambiguate it as a subroutine call, use either an extra space after
+the "-", C<- f(...)>, or an extra set of parentheses, C<-(f(...))>.
+To disambiguate it as a file test, use an extra space after the operator
+name C<-f (...)>, or add the space and remove the parentheses, C<-f ...>.
+

 =item Ambiguous call resolved as CORE::%s(), qualify as such or use &
 
 (W ambiguous) A subroutine you have declared has the same name as a Perl
 =item Ambiguous call resolved as CORE::%s(), qualify as such or use &
 
 (W ambiguous) A subroutine you have declared has the same name as a Perl


@@ -76,6 +87,13 @@ on the operator (e.g. C<CORE::log($x)>) or by declaring the subroutine
 to be an object method (see L<perlsub/"Subroutine Attributes"> or
 L<attributes>).
 
 to be an object method (see L<perlsub/"Subroutine Attributes"> or
 L<attributes>).
 

+=item Ambiguous range in transliteration operator
+
+(F) You wrote something like C<tr/a-z-0//> which doesn't mean anything at
+all.  To include a C<-> character in a transliteration, put it either
+first or last.  (In the past, C<tr/a-z-0//> was synonymous with
+C<tr/a-y//>, which was probably not what you would have expected.)
+

 =item Ambiguous use of %s resolved as %s
 
 (W ambiguous)(S) You said something that may not be interpreted the way
 =item Ambiguous use of %s resolved as %s
 
 (W ambiguous)(S) You said something that may not be interpreted the way


@@ -175,6 +193,29 @@ spots.  This is now heavily deprecated.
 must either both be scalars or both be lists.  Otherwise Perl won't
 know which context to supply to the right side.
 
 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
+
+(F) When 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
+
+(F) The CLASSNAME argument to the bless() operator is expected to be
+the name of the package to bless the resulting object into. You've
+supplied instead a reference to something: perhaps you wrote
+
+    bless $self, $proto;
+
+when you intended
+
+    bless $self, ref($proto) || $proto;
+
+If you actually want to bless into the stringified version
+of the reference supplied, you need to stringify it yourself, for
+example by:
+
+    bless $self, "$proto";
+

 =item Attempt to free non-arena SV: 0x%lx
 
 (P internal) All SV objects are supposed to be allocated from arenas
 =item Attempt to free non-arena SV: 0x%lx
 
 (P internal) All SV objects are supposed to be allocated from arenas


@@ -254,9 +295,9 @@ open(), or did it in another package.
 
 (S malloc) An internal routine called free() on something that had never
 been malloc()ed in the first place. Mandatory, but can be disabled by
 
 (S malloc) An internal routine called free() on something that had never
 been malloc()ed in the first place. Mandatory, but can be disabled by

-setting environment variable C<PERL_BADFREE> to 1.
+setting environment variable C<PERL_BADFREE> to 0.

 
 

-This message can be quite often seen with DB_File on systems with "hard"
+This message can be seen quite often with DB_File on systems with "hard"

 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
 
 dynamic linking, like C<AIX> and C<OS/2>. It is a bug of C<Berkeley DB>
 which is left unnoticed if C<DB> uses I<forgiving> system malloc().
 


@@ -379,7 +420,7 @@ check the return value of your socket() call?  See L<perlfunc/bind>.
 =item Bizarre copy of %s in %s
 
 (P) Perl detected an attempt to copy an internal value that is not
 =item Bizarre copy of %s in %s
 
 (P) Perl detected an attempt to copy an internal value that is not

-copiable.
+copyable.

 
 =item B<-P> not allowed for setuid/setgid script
 
 
 =item B<-P> not allowed for setuid/setgid script
 


@@ -419,12 +460,6 @@ L<perlfunc/pack>.
 (F) Only hard references may be blessed.  This is how Perl "enforces"
 encapsulation of objects.  See L<perlobj>.
 
 (F) Only hard references may be blessed.  This is how Perl "enforces"
 encapsulation of objects.  See L<perlobj>.
 

-=item Can't break at that line
-
-(S internal) A warning intended to only be printed while running within
-the debugger, indicating the line number specified wasn't the location
-of a statement that could be stopped at.
-

 =item Can't call method "%s" in empty package "%s"
 
 (F) You called a method correctly, and it correctly indicated a package
 =item Can't call method "%s" in empty package "%s"
 
 (F) You called a method correctly, and it correctly indicated a package


@@ -538,10 +573,11 @@ C<-i.bak>, or some such.
 characters and Perl was unable to create a unique filename during
 inplace editing with the B<-i> switch.  The file was ignored.
 
 characters and Perl was unable to create a unique filename during
 inplace editing with the B<-i> switch.  The file was ignored.
 

-=item Can't do {n,m} with n > m
+=item Can't do {n,m} with n > m before << HERE in regex m/%s/

 
 

-(F) Minima must be less than or equal to maxima.  If you really want
-your regexp to match something 0 times, just put {0}.  See L<perlre>.
+(F) Minima must be less than or equal to maxima. If you really want your
+regexp to match something 0 times, just put {0}. The << HERE shows in the
+regular expression about where the problem was discovered. See L<perlre>.

 
 =item Can't do setegid!
 
 
 =item Can't do setegid!
 


@@ -626,6 +662,13 @@ If you're getting this error from a here-document, you may have included
 unseen whitespace before or after your closing tag. A good programmer's
 editor will have a way to help you find these characters.
 
 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
 =item Can't fork
 
 (F) A fatal error occurred while trying to fork while opening a


@@ -747,6 +790,12 @@ the file, say, by doing C<make install>.
 functioning as a class, but that package doesn't define that particular
 method, nor does any of its base classes.  See L<perlobj>.
 
 functioning as a class, but that package doesn't define that particular
 method, nor does any of its base classes.  See L<perlobj>.
 

+=item (perhaps you forgot to load "%s"?)
+
+(F) This is an educated guess made in conjunction with the message
+"Can't locate object method \"%s\" via package \"%s\"".  It often means
+that a method requires a package that has not been loaded.
+

 =item Can't locate package %s for @%s::ISA
 
 (W syntax) The @ISA array contained the name of another package that
 =item Can't locate package %s for @%s::ISA
 
 (W syntax) The @ISA array contained the name of another package that


@@ -1012,35 +1061,6 @@ references can be weakened.
 with an assignment operator, which implies modifying the value itself.
 Perhaps you need to copy the value to a temporary, and repeat that.
 
 with an assignment operator, which implies modifying the value itself.
 Perhaps you need to copy the value to a temporary, and repeat that.
 

-=item Character class syntax [%s] belongs inside character classes
-
-(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.
-
-=item Character class syntax [. .] is reserved for future extensions
-
-(W regexp) Within regular expression character classes ([]) the syntax
-beginning with "[." and ending with ".]" is reserved for future
-extensions.  If you need to represent those character sequences inside a
-regular expression character class, just quote the square brackets with
-the backslash: "\[." and ".\]".
-
-=item Character class syntax [= =] is reserved for future extensions
-
-(W regexp) Within regular expression character classes ([]) the syntax
-beginning with "[=" and ending with "=]" is reserved for future
-extensions.  If you need to represent those character sequences inside a
-regular expression character class, just quote the square brackets with
-the backslash: "\[=" and "=\]".
-
-=item Character class [:%s:] unknown
-
-(F) The class in the character class [: :] syntax is unknown.  See
-L<perlre>.
-

 =item chmod() mode argument is missing initial 0
 
 (W chmod) A novice will sometimes say
 =item chmod() mode argument is missing initial 0
 
 (W chmod) A novice will sometimes say


@@ -1051,7 +1071,7 @@ 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.
 
 equivalent to 01411.  Octal constants are introduced with a leading 0 in
 Perl, as in C.
 

-=item Close on unopened file <%s>
+=item close() on unopened filehandle %s

 
 (W unopened) You tried to close a filehandle that was never opened.
 
 
 (W unopened) You tried to close a filehandle that was never opened.
 


@@ -1075,7 +1095,7 @@ arbitrarily.  ("Simple" and "medium" situations are handled without
 recursion and are not subject to a limit.)  Try shortening the string
 under examination; looping in Perl code (e.g. with C<while>) rather than
 in the regular expression engine; or rewriting the regular expression so
 recursion and are not subject to a limit.)  Try shortening the string
 under examination; looping in Perl code (e.g. with C<while>) rather than
 in the regular expression engine; or rewriting the regular expression so

-that it is simpler or backtracks less.  (See L<perlbook> for information
+that it is simpler or backtracks less.  (See L<perlfaq2> for information

 on I<Mastering Regular Expressions>.)
 
 =item connect() on closed socket %s
 on I<Mastering Regular Expressions>.)
 
 =item connect() on closed socket %s


@@ -1084,7 +1104,7 @@ on I<Mastering Regular Expressions>.)
 to check the return value of your socket() call?  See
 L<perlfunc/connect>.
 
 to check the return value of your socket() call?  See
 L<perlfunc/connect>.
 

-=item constant(%s): %s
+=item Constant(%s)%s: %s

 
 (F) The parser found inconsistencies either while attempting to define
 an overloaded constant, or when trying to find the character name
 
 (F) The parser found inconsistencies either while attempting to define
 an overloaded constant, or when trying to find the character name


@@ -1114,8 +1134,8 @@ workarounds.
 
 =item Copy method did not return a reference
 
 
 =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
 
 
 =item CORE::%s is not a keyword
 


@@ -1347,12 +1367,6 @@ you which section of the Perl source code is distressed.
 (F) Your machine apparently doesn't implement fcntl().  What is this, a
 PDP-11 or something?
 
 (F) Your machine apparently doesn't implement fcntl().  What is this, a
 PDP-11 or something?
 

-=item Filehandle %s never opened
-
-(W unopened) An I/O operation was attempted on a filehandle that was
-never initialized.  You need to do an open() or a socket() call, or call
-a constructor from the FileHandle package.
-

 =item Filehandle %s opened only for input
 
 (W io) You tried to write on a read-only filehandle.  If you intended it
 =item Filehandle %s opened only for input
 
 (W io) You tried to write on a read-only filehandle.  If you intended it


@@ -1388,10 +1402,11 @@ some time before now.  Check your logic flow.  flock() operates on
 filehandles.  Are you attempting to call flock() on a dirhandle by the
 same name?
 
 filehandles.  Are you attempting to call flock() on a dirhandle by the
 same name?
 

-=item ?+* follows nothing in regexp
+=item Quantifier follows nothing before << HERE in regex m/%s/

 
 

-(F) You started a regular expression with a quantifier.  Backslash it if
-you meant it literally.   See L<perlre>.
+(F) You started a regular expression with a quantifier. Backslash it if you
+meant it literally. The << HERE shows in the regular expression about where the
+problem was discovered. See L<perlre>.

 
 =item Format not terminated
 
 
 =item Format not terminated
 


@@ -1625,16 +1640,6 @@ C<$ENV{ENV}> or C<$ENV{BASH_ENV}> are derived from data supplied (or
 potentially supplied) by the user.  The script must set the path to a
 known value, using trustworthy data.  See L<perlsec>.
 
 potentially supplied) by the user.  The script must set the path to a
 known value, using trustworthy data.  See L<perlsec>.
 

-=item In string, @%s now must be written as \@%s
-
-(F) It used to be that Perl would try to guess whether you wanted an
-array interpolated or a literal @.  It did this when the string was
-first used at runtime.  Now strings are parsed at compile time, and
-ambiguous instances of @ must be disambiguated, either by prepending a
-backslash to indicate a literal, or by declaring (or using) the array
-within the program before the string (lexically).  (Someday it will
-simply assume that an unbackslashed @ interpolates an array.)
-

 =item Integer overflow in %s number
 
 (W overflow) The hexadecimal, octal or binary number you have specified
 =item Integer overflow in %s number
 
 (W overflow) The hexadecimal, octal or binary number you have specified


@@ -1647,9 +1652,12 @@ transparently promotes all numbers to a floating point representation
 internally--subject to loss of precision errors in subsequent
 operations.
 
 internally--subject to loss of precision errors in subsequent
 operations.
 

-=item internal disaster in regexp
+=item Internal disaster before << HERE in regex m/%s/

 
 (P) Something went badly wrong in the regular expression parser.
 
 (P) Something went badly wrong in the regular expression parser.

+The << HERE shows in the regular expression about where the problem was
+discovered.
+

 
 =item Internal inconsistency in tracking vforks
 
 
 =item Internal inconsistency in tracking vforks
 


@@ -1660,16 +1668,18 @@ L<perlvms/"exec LIST">).  Somehow, this count has become scrambled, so
 Perl is making a guess and treating this C<exec> as a request to
 terminate the Perl script and execute the specified command.
 
 Perl is making a guess and treating this C<exec> as a request to
 terminate the Perl script and execute the specified command.
 

-=item internal urp in regexp at /%s/
+=item Internal urp 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.

 
 

-(P) Something went badly awry in the regular expression parser.

 
 =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
 
 =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
 
 
 =item Invalid %s attribute: %s
 


@@ -1691,6 +1701,11 @@ L<perlfunc/sprintf>.
 (F) The range specified in a character class had a minimum character
 greater than the maximum character.  See L<perlre>.
 
 (F) The range specified in a character class had a minimum character
 greater than the maximum character.  See L<perlre>.
 

+=item invalid [] range "%s" in transliteration operator
+
+(F) The range specified in the tr/// or y/// operator had a minimum
+character greater than the maximum character.  See L<perlop>.
+

 =item Invalid separator character %s in attribute list
 
 (F) Something other than a colon or whitespace was seen between the
 =item Invalid separator character %s in attribute list
 
 (F) Something other than a colon or whitespace was seen between the


@@ -1716,6 +1731,16 @@ silently ignored.
 (F) Your machine apparently doesn't implement ioctl(), which is pretty
 strange for a machine that supports C.
 
 (F) Your machine apparently doesn't implement ioctl(), which is pretty
 strange for a machine that supports C.
 

+=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
+to a subroutine.
+
+=item `%s' is not an overloadable type
+
+(W) You tried to overload a constant type the overload package is unaware of.
+

 =item junk on end of regexp
 
 (P) The regular expression parser is confused.
 =item junk on end of regexp
 
 (P) The regular expression parser is confused.


@@ -1749,12 +1774,24 @@ effective uids or gids failed.
 to check the return value of your socket() call?  See
 L<perlfunc/listen>.
 
 to check the return value of your socket() call?  See
 L<perlfunc/listen>.
 

+=item lstat() on filehandle %s
+
+(W io) You tried to do a lstat on a filehandle.  What did you mean
+by that?  lstat() makes sense only on filenames.  (Perl did a fstat()
+instead on the filehandle.)
+

 =item Lvalue subs returning %s not implemented yet
 
 (F) Due to limitations in the current implementation, array and hash
 values cannot be returned in subroutines used in lvalue context.  See
 L<perlsub/"Lvalue subroutines">.
 
 =item Lvalue subs returning %s not implemented yet
 
 (F) Due to limitations in the current implementation, array and hash
 values cannot be returned in subroutines used in lvalue context.  See
 L<perlsub/"Lvalue subroutines">.
 

+=item Lookbehind longer than %d not implemented before << HERE in reges m/%s/
+
+(F) There is currently a limit on the length of string which lookbehind can
+handle. This restriction may be eased in a future release. The << HERE shows in
+the regular expression about where the problem was discovered.
+

 =item Malformed PERLLIB_PREFIX
 
 (F) An error peculiar to OS/2.  PERLLIB_PREFIX should be of the form
 =item Malformed PERLLIB_PREFIX
 
 (F) An error peculiar to OS/2.  PERLLIB_PREFIX should be of the form


@@ -1770,6 +1807,15 @@ a builtin library search path, prefix2 is substituted.  The error may
 appear if components are not found, or are too long.  See
 "PERLLIB_PREFIX" in L<perlos2>.
 
 appear if components are not found, or are too long.  See
 "PERLLIB_PREFIX" in L<perlos2>.
 

+=item Malformed UTF-8 character (%s)
+
+Perl detected something that didn't comply with UTF-8 encoding rules.
+
+=item Malformed UTF-16 surrogate
+
+Perl thought it was reading UTF-16 encoded character data but while
+doing it Perl met a malformed Unicode surrogate.
+

 =item %s matches null string many times
 
 (W regexp) The pattern you've specified would be an infinite loop if the
 =item %s matches null string many times
 
 (W regexp) The pattern you've specified would be an infinite loop if the


@@ -1856,6 +1902,14 @@ catches that.  But an easy way to do the same thing is:
 
 Another way is to assign to a substr() that's off the end of the string.
 
 
 Another way is to assign to a substr() that's off the end of the string.
 

+Yet another way is to assign to a C<foreach> loop I<VAR> when I<VAR>
+is aliased to a constant in the look I<LIST>:
+
+        $x = 1;
+        foreach my $n ($x, 2) {
+            $n *= 2; # modifies the $x, but fails on attempt to modify the 2
+        } 
+

 =item Modification of non-creatable array value attempted, %s
 
 (F) You tried to make an array value spring into existence, and the
 =item Modification of non-creatable array value attempted, %s
 
 (F) You tried to make an array value spring into existence, and the


@@ -1926,14 +1980,16 @@ provided for this purpose.
 (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.
 
 (F) You tried to do a read/write/send/recv operation with a buffer
 length that is less than 0.  This is difficult to imagine.
 

-=item nested *?+ in regexp
+=item Nested quantifiers before << HERE in regex m/%s/

 
 

-(F) You can't quantify a quantifier without intervening parentheses.  So
-things like ** or +* or ?* are illegal.
+(F) You can't quantify a quantifier without intervening parentheses. So
+things like ** or +* or ?* are illegal. The << HERE shows in the regular
+expression about where the problem was discovered.

 
 Note, however, that the minimal matching quantifiers, C<*?>, C<+?>, and
 C<??> appear to be nested quantifiers, but aren't.  See L<perlre>.
 
 
 Note, however, 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 never introduced
 
 (S internal) The symbol in question was declared but somehow went out of


@@ -2212,6 +2268,11 @@ L<perlport> for more on portability concerns.
 
 See also L<perlport> for writing portable code.
 
 
 See also L<perlport> for writing portable code.
 

+=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.
+

 =item Odd number of elements in hash assignment
 
 (W misc) You specified an odd number of elements to initialize a hash,
 =item Odd number of elements in hash assignment
 
 (W misc) You specified an odd number of elements to initialize a hash,


@@ -2224,6 +2285,17 @@ pointing outside the buffer.  This is difficult to imagine.  The sole
 exception to this is that C<sysread()>ing past the buffer will extend
 the buffer and zero pad the new area.
 
 exception to this is that C<sysread()>ing past the buffer will extend
 the buffer and zero pad the new area.
 

+=item -%s on unopened filehandle %s
+
+(W unopened) You tried to invoke a file test operator on a filehandle
+that isn't open.  Check your logic.  See also L<perlfunc/-X>.
+
+=item %s() on unopened %s %s
+
+(W unopened) An I/O operation was attempted on a filehandle that was
+never initialized.  You need to do an open(), a sysopen(), or a socket()
+call, or call a constructor from the FileHandle package.
+

 =item oops: oopsAV
 
 (S internal) An internal warning that the grammar is screwed up.
 =item oops: oopsAV
 
 (S internal) An internal warning that the grammar is screwed up.


@@ -2275,7 +2347,8 @@ The request was judged to be small, so the possibility to trap it
 depends on the way perl was compiled.  By default it is not trappable.
 However, if compiled for this, Perl may use the contents of C<$^M> as an
 emergency pool after die()ing with this message.  In this case the error
 depends on the way perl was compiled.  By default it is not trappable.
 However, if compiled for this, Perl may use the contents of C<$^M> as an
 emergency pool after die()ing with this message.  In this case the error

-is trappable I<once>.
+is trappable I<once>, and the error message will include the line and file
+where the failed request happened.

 
 =item Out of memory during ridiculously large request
 
 
 =item Out of memory during ridiculously large request
 


@@ -2472,6 +2545,11 @@ was string.
 
 (P) The lexer got into a bad state while processing a case modifier.
 
 
 (P) The lexer got into a bad state while processing a case modifier.
 

+=item panic: utf16_to_utf8: odd bytelen
+
+(P) Something tried to call utf16_to_utf8 with an odd (as opposed
+to even) byte length. 
+

 =item Parentheses missing around "%s" list
 
 (W parenthesis) You said something like
 =item Parentheses missing around "%s" list
 
 (W parenthesis) You said something like


@@ -2508,13 +2586,23 @@ C<sh>-shell in.  See "PERL_SH_DIR" in L<perlos2>.
 
 Exactly what were the failed locale settings varies.  In the above the
 settings were that the LC_ALL was "En_US" and the LANG had no value.
 
 Exactly what were the failed locale settings varies.  In the above the
 settings were that the LC_ALL was "En_US" and the LANG had no value.

-This error means that Perl detected that you and/or your system
-administrator have set up the so-called variable system but Perl could
-not use those settings.  This was not dead serious, fortunately: there
-is a "default locale" called "C" that Perl can and will use, the script
-will be run.  Before you really fix the problem, however, you will get
-the same error message each time you run Perl.  How to really fix the
-problem can be found in L<perllocale> section B<LOCALE PROBLEMS>.
+This error means that Perl detected that you and/or your operating
+system supplier and/or system administrator have set up the so-called
+locale system but Perl could not use those settings.  This was not
+dead serious, fortunately: there is a "default locale" called "C" that
+Perl can and will use, the script will be run.  Before you really fix
+the problem, however, you will get the same error message each time
+you run Perl.  How to really fix the problem can be found in
+L<perllocale> section B<LOCALE PROBLEMS>.
+
+=item perlio: 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
 
 
 =item Permission denied
 


@@ -2526,6 +2614,35 @@ problem can be found in L<perllocale> section B<LOCALE PROBLEMS>.
 process which isn't a subprocess of the current process.  While this is
 fine from VMS' perspective, it's probably not what you intended.
 
 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
+
+(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.
+
+=item POSIX  syntax [. .] is reserved for future extensions
+
+(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: "\[." and ".\]".
+
+=item POSIX syntax [= =] is reserved for future extensions
+
+(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: "\[=" and "=\]".
+
+=item POSIX class [:%s:] unknown
+
+(F) The class in the character class [: :] syntax is unknown.  See
+L<perlre>.
+

 =item POSIX getpgrp can't take an argument
 
 (F) Your system has POSIX getpgrp(), which takes no argument, unlike
 =item POSIX getpgrp can't take an argument
 
 (F) Your system has POSIX getpgrp(), which takes no argument, unlike


@@ -2648,6 +2765,20 @@ in L<perlos2>.
 (S unsafe) The subroutine being declared or defined had previously been
 declared or defined with a different function prototype.
 
 (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/
+
+(F) There is currently a limit to the size of the min and max values of the
+{min,max} construct. The << HERE shows in the regular expression about where
+the problem was discovered. See L<perlre>.
+
+=item Quantifier unexpected on zero-length expression before << HERE in regex m/%s/
+
+(W regexp) You applied a regular expression quantifier in a place where
+it makes no sense, such as on a zero-width assertion.  Try putting the
+quantifier inside the assertion instead.  For example, the way to match
+"abc" provided that it is followed by three repetitions of "xyz" is
+C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+

 =item Range iterator outside integer range
 
 (F) One (or both) of the numeric arguments to the range operator ".."
 =item Range iterator outside integer range
 
 (F) One (or both) of the numeric arguments to the range operator ".."


@@ -2708,17 +2839,22 @@ Doing so has no effect.
 (W internal) The internal sv_replace() function was handed a new SV with
 a reference count of other than 1.
 
 (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/
+
+(F) You used something like C<\7> in your regular expression, but there are
+not at least seven sets of capturing parentheses in the expression. If you
+wanted to have the character with value 7 inserted into the regular expression,
+prepend a zero to make the number at least two digits: C<\07>
+
+The << HERE shows in the regular expression about where the problem was
+discovered.
+

 =item regexp memory corruption
 
 (P) The regular expression engine got confused by what the regular
 expression compiler gave it.
 
 =item regexp memory corruption
 
 (P) The regular expression engine got confused by what the regular
 expression compiler gave it.
 

-=item regexp *+ operand could be empty
-
-(F) The part of the regexp subject to either the * or + quantifier could
-match an empty string.
-
-=item regexp out of space
+=item Regexp out of space

 
 (P) A "can't happen" error, because safemalloc() should have caught it
 earlier.
 
 (P) A "can't happen" error, because safemalloc() should have caught it
 earlier.


@@ -2787,7 +2923,7 @@ or setgid bit set.  This doesn't make much sense.
 construct.  Remember that bracketing delimiters count nesting level.
 Missing the leading C<$> from a variable C<$m> may cause this error.
 
 construct.  Remember that bracketing delimiters count nesting level.
 Missing the leading C<$> from a variable C<$m> may cause this error.
 

-=item %sseek() on unopened file
+=item %sseek() on unopened filehandle

 
 (W unopened) You tried to use the seek() or sysseek() function on a
 filehandle that was either never opened or has since been closed.
 
 (W unopened) You tried to use the seek() or sysseek() function on a
 filehandle that was either never opened or has since been closed.


@@ -2796,6 +2932,11 @@ filehandle that was either never opened or has since been closed.
 
 (F) This machine doesn't implement the select() system call.
 
 
 (F) This machine doesn't implement the select() system call.
 

+=item Self-ties of arrays and hashes are not supported
+
+(F) Self-ties are of arrays and hashes are not supported in
+the current implementation.
+

 =item Semicolon seems to be missing
 
 (W semicolon) A nearby syntax error was probably caused by a missing
 =item Semicolon seems to be missing
 
 (W semicolon) A nearby syntax error was probably caused by a missing


@@ -2815,22 +2956,31 @@ scalar that had previously been marked as free.
 (W closed) The socket you're sending to got itself closed sometime
 before now.  Check your logic flow.
 
 (W closed) The socket you're sending to got itself closed sometime
 before now.  Check your logic flow.
 

-=item Sequence (? incomplete
+=item Sequence (? incomplete before << HERE mark in regex m/%s/

 
 

-(F) A regular expression ended with an incomplete extension (?.  See
+(F) A regular expression ended with an incomplete extension (?. The <<<HERE
+shows in the regular expression about where the problem was discovered. See

 L<perlre>.
 
 L<perlre>.
 

-=item Sequence (?%s...) not implemented
+=item Sequence (?{...}) not terminated or not {}-balanced in regex 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>.
+
+=item Sequence (?%s...) not implemented before << HERE mark in regex m/%s/

 
 

-(F) A proposed regular expression extension has the character reserved
-but has not yet been written.  See L<perlre>.
+(F) A proposed regular expression extension has the character reserved but
+has not yet been written. The << HERE shows in the regular expression about
+where the problem was discovered. See L<perlre>.

 
 

-=item Sequence (?%s...) not recognized
+=item Sequence (?%s...) not recognized before << HERE mark in regex m/%s/

 
 (F) You used a regular expression extension that doesn't make sense.
 
 (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>.
 
 See L<perlre>.
 

-=item Sequence (?#... not terminated
+=item Sequence (?#... not terminated in regex m/%s/

 
 (F) A regular expression comment must be terminated by a closing
 parenthesis.  Embedded parentheses aren't allowed.  See L<perlre>.
 
 (F) A regular expression comment must be terminated by a closing
 parenthesis.  Embedded parentheses aren't allowed.  See L<perlre>.


@@ -2962,19 +3112,10 @@ unless there was a failure.  You probably wanted to use system()
 instead, which does return.  To suppress this warning, put the exec() in
 a block by itself.
 
 instead, which does return.  To suppress this warning, put the exec() in
 a block by itself.
 

-=item Stat on unopened file <%s>
-
-(W unopened) You tried to use the stat() function (or an equivalent file
-test) on a filehandle that was either never opened or has since been
-closed.
-
-=item Strange *+?{} on zero-length expression
+=item stat() on unopened filehandle %s

 
 

-(W regexp) You applied a regular expression quantifier in a place where
-it makes no sense, such as on a zero-width assertion.  Try putting the
-quantifier inside the assertion instead.  For example, the way to match
-"abc" provided that it is followed by three repetitions of "xyz" is
-C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>.
+(W unopened) You tried to use the stat() function on a filehandle that
+was either never opened or has since been closed.

 
 =item Stub found while resolving method `%s' overloading %s
 
 
 =item Stub found while resolving method `%s' overloading %s
 


@@ -3023,6 +3164,24 @@ assignment or as a subroutine argument for example).
 (F) Your Perl was compiled with B<-D>SETUID_SCRIPTS_ARE_SECURE_NOW, but
 a version of the setuid emulator somehow got run anyway.
 
 (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/
+
+(F) A (?(condition)if-clause|else-clause) construct can have at most two
+branches (the if-clause and the else-clause). If you want one or both to
+contain alternation, such as using C<this|that|other>, enclose it in
+clustering parentheses:
+
+    (?(condition)(?:this|that|other)|else-clause)
+
+The << HERE shows in the regular expression about where the problem was
+discovered. See L<perlre>.
+
+=item Switch condition not recognized before << HERE in regex m/%s/
+
+(F) If the argument to the (?(...)if-clause|else-clause) construct is a
+number, it can be only a number. The << HERE shows in the regular expression
+about where the problem was discovered. See L<perlre>.
+

 =item switching effective %s is not implemented
 
 (F) While under the C<use filetest> pragma, we cannot switch the real
 =item switching effective %s is not implemented
 
 (F) While under the C<use filetest> pragma, we cannot switch the real


@@ -3077,16 +3236,11 @@ before now.  Check your logic flow.
 (F) You tried to use C<goto> to reach a label that was too deeply nested
 for Perl to reach.  Perl is doing you a favor by refusing.
 
 (F) You tried to use C<goto> to reach a label that was too deeply nested
 for Perl to reach.  Perl is doing you a favor by refusing.
 

-=item tell() on unopened file
+=item tell() on unopened filehandle

 
 (W unopened) You tried to use the tell() function on a filehandle that
 was either never opened or has since been closed.
 
 
 (W unopened) You tried to use the tell() function on a filehandle that
 was either never opened or has since been closed.
 

-=item Test on unopened file <%s>
-
-(W unopened) You tried to invoke a file test operator on a filehandle
-that isn't open.  Check your logic.  See also L<perlfunc/-X>.
-

 =item That use of $[ is unsupported
 
 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted
 =item That use of $[ is unsupported
 
 (F) Assignment to C<$[> is now strictly circumscribed, and interpreted


@@ -3115,7 +3269,7 @@ will deny it.
 The function indicated isn't implemented on this architecture, according
 to the probings of Configure.
 
 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
 
 (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


@@ -3297,11 +3451,23 @@ Check the #! line, or manually feed your script into Perl yourself.
 (F) The unexec() routine failed for some reason.  See your local FSF
 representative, who probably put it there in the first place.
 
 (F) The unexec() routine failed for some reason.  See your local FSF
 representative, who probably put it there in the first place.
 

+

 =item Unknown BYTEORDER
 
 (F) There are no byte-swapping functions for a machine with this byte
 order.
 
 =item Unknown BYTEORDER
 
 (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/
+
+(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).
+
+The << HERE shows in the regular expression about where the problem was
+discovered.  See L<perlre>.
+

 =item Unknown open() mode '%s'
 
 (F) The second argument of 3-argument open() is not among the list
 =item Unknown open() mode '%s'
 
 (F) The second argument of 3-argument open() is not among the list


@@ -3315,13 +3481,14 @@ iterating over it, and someone else stuck a message in the stream of
 data Perl expected.  Someone's very confused, or perhaps trying to
 subvert Perl's population of %ENV for nefarious purposes.
 
 data Perl expected.  Someone's very confused, or perhaps trying to
 subvert Perl's population of %ENV for nefarious purposes.
 

-=item unmatched [] in regexp
+=item unmatched [ before << HERE mark in regex m/%s/

 
 

-(F) The brackets around a character class must match.  If you wish to
+(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
 include a closing bracket in a character class, backslash it or put it

-first.  See L<perlre>.
+first. See L<perlre>. The << HERE shows in the regular expression about
+where the escape was discovered.

 
 

-=item unmatched () in regexp
+=item unmatched ( in regexp before << HERE mark in regex 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
 
 (F) Unbackslashed parentheses must always be balanced in regular
 expressions.  If you're a vi user, the % key is valuable for finding the


@@ -3353,12 +3520,14 @@ script, a binary program, or a directory as a Perl program.
 recognized by Perl inside character classes.  The character was
 understood literally.
 
 recognized by Perl inside character classes.  The character was
 understood literally.
 

-=item /%s/: Unrecognized escape \\%c passed through
+=item Unrecognized escape \\%c passed through before << HERE in m/%s/

 
 (W regexp) You used a backslash-character combination which is not
 
 (W regexp) You used a backslash-character combination which is not

-recognized by Perl.  This combination appears in an interpolated
-variable or a C<'>-delimited regular expression.  The character was
-understood literally.
+recognized by Perl. This combination appears in an interpolated variable or
+a C<'>-delimited regular expression. The character was understood
+literally. The << HERE shows in the regular expression about where the escape
+was discovered.
+

 
 =item Unrecognized escape \\%c passed through
 
 
 =item Unrecognized escape \\%c passed through
 


@@ -3425,6 +3594,12 @@ an attribute list, but the matching closing (right) parenthesis
 character was not found.  You may need to add (or remove) a backslash
 character to get your parentheses to balance.  See L<attributes>.
 
 character was not found.  You may need to add (or remove) a backslash
 character to get your parentheses to balance.  See L<attributes>.
 

+=item Unterminated compressed integer
+
+(F) An argument to unpack("w",...) was incompatible with the BER
+compressed integer format and could not be converted to an integer.
+See L<perlfunc/pack>.
+

 =item Unterminated <> operator
 
 (F) The lexer saw a left angle bracket in a place where it was expecting
 =item Unterminated <> operator
 
 (F) The lexer saw a left angle bracket in a place where it was expecting


@@ -3639,6 +3814,12 @@ anonymous, using the C<sub {}> syntax.  When inner anonymous subs that
 reference variables in outer subroutines are called or referenced, they
 are automatically rebound to the current values of such variables.
 
 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/
+
+(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.
+

 =item Version number must be a constant number
 
 (P) The attempt to translate a C<use Module n.n LIST> statement into
 =item Version number must be a constant number
 
 (P) The attempt to translate a C<use Module n.n LIST> statement into


@@ -3675,6 +3856,10 @@ but in actual fact, you got
 
 So put in parentheses to say what you really mean.
 
 
 So put in parentheses to say what you really mean.
 

+=item Wide character in %s
+
+(F) 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
 =item write() on closed filehandle %s
 
 (W closed) The filehandle you're writing to got itself closed sometime