$Config{ivsize}. For portability, be sure to mask off the excess bits
in the result of unary C<~>, e.g., C<~$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
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 misc) This prefix usually indicates that a DESTROY() method raised
the indicated exception. Since destructors are usually called by
See Server error.
-=item Did you mean "local" instead of "our"?
+=item (Did you mean "local" instead of "our"?)
(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.
=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 Tru64 (aka Digital UNIX, aka DEC OSF/1) lib/sdbm test failure with gcc
+
+If compiled with gcc 2.95 the lib/sdbm test will fail (dump core).
+The cure is to use the vendor cc, it comes with the operating system
+and produces good code.
+
+=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
https://perl5.git.perl.org / perl5.git / blobdiff