$Config{ivsize}. For portability, be sure to mask off the excess bits
in the result of unary C<~>, e.g., C<~$x & 0xffffffff>.
+=head2 More builtins taint their results
+
+The C<passwd> and C<shell> fields returned by the getpwent(), getpwnam(),
+and getpwuid() are now tainted, because the user can affect their own
+encrypted password and login shell.
+
+The variable modified by shmread(), and messages returned by msgrcv()
+(and its object-oriented interface IPC::SysV::Msg::rcv) are also tainted,
+because other untrusted processes can modify messages and shared memory
+segments for their own nefarious purposes.
+
+To avoid these new tainting behaviors, you can build Perl with the
+Configure option C<-Accflags=-DINCOMPLETE_TAINTS>. Beware that the
+ensuing perl binary may be insecure.
+
=back
=head2 C Source Incompatibilities
=head2 Weak references
- WARNING: This is an experimental feature.
+ WARNING: This is an experimental feature. Details are subject to change.
In previous versions of Perl, you couldn't cache objects so as
to allow them to be deleted if the last reference from outside
constructs now generate a warning, since they may take on new
semantics in later versions of Perl.
+Many diagnostics now report the internal operation in which the warning
+was provoked, like so:
+
+ Use of uninitialized value in concatenation (.) at (eval 1) line 1.
+ Use of uninitialized value in print at (eval 1) line 1.
+
+Diagnostics that occur within eval may also report the file and line
+number where the eval is located, in addition to the eval sequence
+number and the line number within the evaluated text itself. For
+example:
+
+ Not enough arguments for scalar at (eval 4)[newlib/perl5db.pl:1411] line 2, at EOF
+
=head1 Performance enhancements
=head2 Simple sort() using { $a <=> $b } and the like are optimized
Support for non-Unix platforms has been improved.
+=head2 perldoc
+
+C<perldoc> has been reworked to avoid possible security holes.
+It will not by default let itself be run as the superuser, but you
+may still use the B<-U> switch to try to make it drop privileges
+first.
+
+=head2 The Perl Debugger
+
+Many bug fixes and enhancements were added to F<perl5db.pl>, the
+Perl debugger. The help documentation was rearranged. New commands
+include C<< < ? >>, C<< > ? >>, and C<< { ? >> to list out current
+actions, C<man I<docpage>> to run your doc viewer on some perl
+docset, and support for quoted options. The help information was
+rearranged, and should be viewable once again if you're using B<less>
+as your pager. A serious security hole was plugged--you should
+immediately remove all older versions of the Perl debugger as
+installed in previous releases, all the way back to perl3, from
+your system to avoid being bitten by this.
+
=head1 Documentation Changes
=over 4
An introduction to using the Perl Compiler suite.
+=item perldebug.pod
+
+All material unrelated to running the Perl debugger, plus all
+low-level guts-like details that risked crushing the casual user
+of the debugger, have been relocated from the old manpage to the
+next entry below.
+
+=item perldebguts.pod
+
+This new manpage contains excessively low-level material not related
+to the Perl debugger, but slightly related to debugging Perl itself.
+It also contains some arcane internal details of how the debugging
+process works that may only be of interest to developers of Perl
+debuggers.
+
=item perlfilter.pod
An introduction to writing Perl source filters.
=item "%s" variable %s masks earlier declaration in same %s
-(W) A "my" or "our" variable has been redeclared in the current scope or statement,
+(W misc) A "my" or "our" variable has been redeclared in the current scope or statement,
effectively eliminating all access to the previous instance. This is almost
always a typographical error. Note that the earlier variable will still exist
until the end of the scope or until all closure referents to it are
=item "our" variable %s redeclared
-(W) You seem to have already declared the same global once before in the
+(W misc) You seem to have already declared the same global once before in the
current lexical scope.
=item '!' allowed only after types %s
=item /%s/: Unrecognized escape \\%c passed through
-(W) You used a backslash-character combination which is not recognized
+(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.
=item /%s/: Unrecognized escape \\%c in character class passed through
-(W) You used a backslash-character combination which is not recognized
+(W regexp) You used a backslash-character combination which is not recognized
by Perl inside character classes. The character was understood literally.
=item /%s/ should probably be written as "%s"
-(W) You have used a pattern where Perl expected to find a string,
+(W syntax) You have used a pattern where Perl expected to find a string,
as in the first argument to C<join>. Perl will treat the true
or false result of matching the pattern against $_ as the string,
which is probably not what you had in mind.
=item %s() called too early to check prototype
-(W) You've called a function that has a prototype before the parser saw a
+(W prototype) You've called a function that has a prototype before the parser saw a
definition or declaration for it, and Perl could not check that the call
conforms to the prototype. You need to either add an early prototype
declaration for the subroutine in question, or move the subroutine
=item %s package attribute may clash with future reserved word: %s
-(W) A lowercase attribute name was used that had a package-specific handler.
+(W reserved) A lowercase attribute name was used that had a package-specific handler.
That name might have a meaning to Perl itself some day, even though it
doesn't yet. Perhaps you should use a mixed-case attribute name, instead.
See L<attributes>.
-=item (in cleanup) %s
+=item (in cleanup) %s
-(W) This prefix usually indicates that a DESTROY() method raised
+(W misc) This prefix usually indicates that a DESTROY() method raised
the indicated exception. Since destructors are usually called by
the system at arbitrary points during execution, and often a vast
number of times, the warning is issued only once for any number
=item Bareword found in conditional
-(W) The compiler found a bareword where it expected a conditional,
+(W bareword) The compiler found a bareword where it expected a conditional,
which often indicates that an || or && was parsed as part of the
last argument of the previous construct, for example:
=item Binary number > 0b11111111111111111111111111111111 non-portable
-(W) The binary number you specified is larger than 2**32-1
+(W portable) The binary number you specified is larger than 2**32-1
(4294967295) and therefore non-portable between systems. See
L<perlport> for more on portability concerns.
=item Bit vector size > 32 non-portable
-(W) Using bit vector sizes larger than 32 is non-portable.
+(W portable) Using bit vector sizes larger than 32 is non-portable.
=item Buffer overflow in prime_env_iter: %s
-(W) A warning peculiar to VMS. While Perl was preparing to iterate over
+(W internal) A warning peculiar to VMS. While Perl was preparing to iterate over
%ENV, it encountered a logical name or symbol definition which was too long,
so it was truncated to the string shown.
=item Can't ignore signal CHLD, forcing to default
-(W) Perl has detected that it is being run with the SIGCHLD signal
+(W signal) Perl has detected that it is being run with the SIGCHLD signal
(sometimes known as SIGCLD) disabled. Since disabling this signal
will interfere with proper determination of exit status of child
processes, Perl has reset the signal to its default value.
=item Character class syntax [%s] belongs inside character classes
-(W) The character class constructs [: :], [= =], and [. .] go
+(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
indicates a syntax error in dereferencing the constant value.
See L<perlsub/"Constant Functions"> and L<constant>.
-=item constant(%s): %%^H is not localized
-
-(F) When setting compile-time-lexicalized hash %^H one should set the
-corresponding bit of $^H as well.
-
=item constant(%s): %s
-(F) Compile-time-substitutions (such as overloaded constants and
-character names) were not correctly set up.
+(F) The parser found inconsistencies either while attempting to define an
+overloaded constant, or when trying to find the character name specified
+in the C<\N{...}> escape. Perhaps you forgot to load the corresponding
+C<overload> or C<charnames> pragma? See L<charnames> and L<overload>.
=item CORE::%s is not a keyword
See Server error.
-=item Did you mean "local" instead of "our"?
+=item (Did you mean "local" instead of "our"?)
-(W) Remember that "our" does not localize the declared global variable.
+(W misc) Remember that "our" does not localize the declared global variable.
You have declared it again in the same lexical scope, which seems superfluous.
=item Document contains no data
=item false [] range "%s" in regexp
-(W) A character class range must start and end at a literal character, not
+(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>.
=item Filehandle %s opened only for output
-(W) You tried to read from a filehandle opened only for writing. If you
+(W io) You tried to read from a filehandle opened only for writing. If you
intended it to be a read/write filehandle, you needed to open it with
"+<" or "+>" or "+>>" instead of with "<" or nothing. If
you intended only to read from the file, use "<". See
=item flock() on closed filehandle %s
-(W) The filehandle you're attempting to flock() got itself closed some
+(W closed) The filehandle you're attempting to flock() got itself closed 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?
=item Hexadecimal number > 0xffffffff non-portable
-(W) The hexadecimal number you specified is larger than 2**32-1
+(W portable) The hexadecimal number you specified is larger than 2**32-1
(4294967295) and therefore non-portable between systems. See
L<perlport> for more on portability concerns.
=item Ill-formed CRTL environ value "%s"
-(W) A warning peculiar to VMS. Perl tried to read the CRTL's internal
+(W internal) A warning peculiar to VMS. Perl tried to read the CRTL's internal
environ array, and encountered an element without the C<=> delimiter
used to spearate keys from values. The element is ignored.
=item Ill-formed message in prime_env_iter: |%s|
-(W) A warning peculiar to VMS. Perl tried to read a logical name
+(W internal) A warning peculiar to VMS. Perl tried to read a logical name
or CLI symbol definition when preparing to iterate over %ENV, and
didn't see the expected delimiter between key and value, so the
line was ignored.
=item Illegal binary digit %s ignored
-(W) You may have tried to use a digit other than 0 or 1 in a binary number.
+(W digit) You may have tried to use a digit other than 0 or 1 in a binary number.
Interpretation of the binary number stopped before the offending digit.
=item Illegal number of bits in vec
=item Integer overflow in %s number
-(W) The hexadecimal, octal or binary number you have specified either
+(W overflow) The hexadecimal, octal or binary number you have specified either
as a literal or as an argument to hex() or oct() is too big for your
architecture, and has been converted to a floating point number. On a
32-bit architecture the largest hexadecimal, octal or binary number
=item Missing command in piped open
-(W) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
+(W pipe) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
construction, but the command was missing or blank.
=item Missing name in "my sub"
=item Octal number > 037777777777 non-portable
-(W) The octal number you specified is larger than 2**32-1 (4294967295)
+(W portable) The octal number you specified is larger than 2**32-1 (4294967295)
and therefore non-portable between systems. See L<perlport> for more
on portability concerns.
=item Parentheses missing around "%s" list
-(W) You said something like
+(W parenthesis) You said something like
my $foo, $bar = @_;
=item Possible Y2K bug: %s
-(W) You are concatenating the number 19 with another number, which
+(W y2k) You are concatenating the number 19 with another number, which
could be a potential Year 2000 problem.
+=item pragma "attrs" is deprecated, use "sub NAME : ATTRS" instead
+
+(W deprecated) You have written somehing like this:
+
+ sub doit
+ {
+ use attrs qw(locked);
+ }
+
+You should use the new declaration syntax instead.
+
+ sub doit : locked
+ {
+ ...
+
+The C<use attrs> pragma is now obsolete, and is only provided for
+backward-compatibility. See L<perlsub/"Subroutine Attributes">.
+
+
=item Premature end of script headers
See Server error.
=item Reference is already weak
-(W) You have attempted to weaken a reference that is already weak.
+(W misc) You have attempted to weaken a reference that is already weak.
Doing so has no effect.
=item setpgrp can't take arguments
=item Strange *+?{} on zero-length expression
-(W) You applied a regular expression quantifier in a place where it
+(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
=item This Perl can't set CRTL environ elements (%s=%s)
-(W) Warnings peculiar to VMS. You tried to change or delete an element
+(W internal) Warnings peculiar to VMS. You tried to change or delete an element
of the CRTL's internal environ array, but your copy of Perl wasn't
built with a CRTL that contained the setenv() function. You'll need to
rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see
L<perlvms>) so that the environ array isn't the target of the change to
%ENV which produced the warning.
+=item Too late to run %s block
+
+(W void) A CHECK or INIT block is being defined during run time proper,
+when the opportunity to run them has already passed. Perhaps you are
+loading a file with C<require> or C<do> when you should be using
+C<use> instead. Or perhaps you should put the C<require> or C<do>
+inside a BEGIN block.
+
=item Unknown open() mode '%s'
(F) The second argument of 3-argument open() is not among the list
=item Unrecognized escape \\%c passed through
-(W) You used a backslash-character combination which is not recognized
+(W misc) You used a backslash-character combination which is not recognized
by Perl. The character was understood literally.
=item Unterminated attribute parameter in attribute list
=item Value of CLI symbol "%s" too long
-(W) A warning peculiar to VMS. Perl tried to read the value of an %ENV
+(W misc) A warning peculiar to VMS. Perl tried to read the value of an %ENV
element from a CLI symbol table, and found a resultant string longer
than 1024 characters. The return value has been truncated to 1024
characters.
=back
+=head1 Known Problems
+
+=head2 Thread test failures
+
+The subtests 19 and 20 of lib/thread.t test are known to fail due to
+fundamental problems in the 5.005 threading implementation. These are
+not new failures--Perl 5.005_0x has the same bugs, but didn't have these
+tests.
+
+=head2 EBCDIC platforms not supported
+
+In earlier releases of Perl, EBCDIC environments like OS390 (also
+known as Open Edition MVS) and VM-ESA were supported. Due to changes
+required by the UTF-8 (Unicode) support, the EBCDIC platforms are not
+supported in Perl 5.6.0.
+
+=head2 In 64-bit HP-UX the lib/io_multihomed test may hang
+
+The lib/io_multihomed test may hang in HP-UX if Perl has been
+configured to be 64-bit. Because other 64-bit platforms do not
+hang in this test, HP-UX is suspect. All other tests pass
+in 64-bit HP-UX. The test attempts to create and connect to
+"multihomed" sockets (sockets which have multiple IP addresses).
+
+=head2 NEXTSTEP 3.3 POSIX test failure
+
+In NEXTSTEP 3.3p2 the implementation of the strftime(3) in the
+operating system libraries is buggy: the %j format numbers the days of
+a month starting from zero, which, while being logical to programmers,
+will cause the subtests 19 to 27 of the lib/posix test may fail.
+
+=head2 UNICOS/mk CC failures during Configure run
+
+In UNICOS/mk the following errors may appear during the Configure run:
+
+ Guessing which symbols your C compiler and preprocessor define...
+ CC-20 cc: ERROR File = try.c, Line = 3
+ ...
+ bad switch yylook 79bad switch yylook 79bad switch yylook 79bad switch yylook 79#ifdef A29K
+ ...
+ 4 errors detected in the compilation of "try.c".
+
+The culprit is the broken awk of UNICOS/mk. The effect is fortunately
+rather mild: Perl itself is not adversely affected by the error, only
+the h2ph utility coming with Perl, and that is rather rarely needed
+these days.
+
+=head2 Arrow operator and arrays
+
+When the left argument to the arrow operator C<< -> >> is an array, or
+the C<scalar> operator operating on an array, the result of the
+operation must be considered erroneous. For example:
+
+ @x->[2]
+ scalar(@x)->[2]
+
+These expressions will get run-time errors in some future release of
+Perl.
+
+=head2 Many features still experimental
+
+As discussed above, many features are still experimental. Interfaces and
+implementation of these features are subject to change, and in extreme cases,
+even subject to removal in some future release of Perl. These features
+include the following:
+
+=over 4
+
+=item Threads
+
+=item Unicode
+
+=item Lvalue subroutines
+
+=item Weak references
+
+=item File globbing now implemented internally
+
+=item The Compiler suite
+
+=item The DB module
+
+=item The regular expression constructs C<(?{ code })> and C<(??{ code })>
+
+=back
+
=head1 BUGS
If you find what you think is a bug, you might check the
projects / p5sagit/p5-mst-13.2.git / blobdiff