perl58delta.1

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

This warns you that \f(CW"[e-mail]"\fR is going to turn into
\&\f(CW\*(C`fred.com\*(C'\fR if you don't backslash the \f(CW\*(C`@\*(C'\fR.
See http://www.plover.com/~mjd/perl/at\-error.html for more details
about the history here.
.Sh "Miscellaneous Changes"
.IX Subsection "Miscellaneous Changes"
.IP "\(bu" 4
\&\s-1AUTOLOAD\s0 is now lvaluable, meaning that you can add the :lvalue attribute
to \s-1AUTOLOAD\s0 subroutines and you can assign to the \s-1AUTOLOAD\s0 return value.
.IP "\(bu" 4
The \f(CW$Config\fR{byteorder} (and corresponding \s-1BYTEORDER\s0 in config.h) was
previously wrong in platforms if sizeof(long) was 4, but sizeof(\s-1IV\s0)
was 8.  The byteorder was only sizeof(long) bytes long (1234 or 4321),
but now it is correctly sizeof(\s-1IV\s0) bytes long, (12345678 or 87654321).
(This problem didn't affect Windows platforms.)
.Sp
Also, \f(CW$Config\fR{byteorder} is now computed dynamically\*(--this is more
robust with \*(L"fat binaries\*(R" where an executable image contains binaries
for more than one binary platform, and when cross-compiling.
.IP "\(bu" 4
\&\f(CW\*(C`perl \-d:Module=arg,arg,arg\*(C'\fR now works (previously one couldn't pass
in multiple arguments.)
.IP "\(bu" 4
\&\f(CW\*(C`do\*(C'\fR followed by a bareword now ensures that this bareword isn't
a keyword (to avoid a bug where \f(CW\*(C`do q(foo.pl)\*(C'\fR tried to call a
subroutine called \f(CW\*(C`q\*(C'\fR).  This means that for example instead of
\&\f(CW\*(C`do format()\*(C'\fR you must write \f(CW\*(C`do &format()\*(C'\fR.
.IP "\(bu" 4
The builtin \fIdump()\fR now gives an optional warning
\&\f(CW\*(C`dump() better written as CORE::dump()\*(C'\fR,
meaning that by default \f(CW\*(C`dump(...)\*(C'\fR is resolved as the builtin
\&\fIdump()\fR which dumps core and aborts, not as (possibly) user-defined
\&\f(CW\*(C`sub dump\*(C'\fR.  To call the latter, qualify the call as \f(CW\*(C`&dump(...)\*(C'\fR.
(The whole \fIdump()\fR feature is to considered deprecated, and possibly
removed/changed in future releases.)
.IP "\(bu" 4
\&\fIchomp()\fR and \fIchop()\fR are now overridable.  Note, however, that their
prototype (as given by \f(CW\*(C`prototype("CORE::chomp")\*(C'\fR is undefined,
because it cannot be expressed and therefore one cannot really write
replacements to override these builtins.
.IP "\(bu" 4
\&\s-1END\s0 blocks are now run even if you exit/die in a \s-1BEGIN\s0 block.
Internally, the execution of \s-1END\s0 blocks is now controlled by
PL_exit_flags & \s-1PERL_EXIT_DESTRUCT_END\s0. This enables the new
behaviour for Perl embedders. This will default in 5.10. See
perlembed.
.IP "\(bu" 4
Formats now support zero-padded decimal fields.
.IP "\(bu" 4
Although \*(L"you shouldn't do that\*(R", it was possible to write code that
depends on Perl's hashed key order (Data::Dumper does this).  The new
algorithm \*(L"One-at-a-Time\*(R" produces a different hashed key order.
More details are in \*(L"Performance Enhancements\*(R".
.IP "\(bu" 4
lstat(\s-1FILEHANDLE\s0) now gives a warning because the operation makes no sense.
In future releases this may become a fatal error.
.IP "\(bu" 4
Spurious syntax errors generated in certain situations, when \fIglob()\fR
caused File::Glob to be loaded for the first time, have been fixed. [561]
.IP "\(bu" 4
Lvalue subroutines can now return \f(CW\*(C`undef\*(C'\fR in list context.  However,
the lvalue subroutine feature still remains experimental.  [561+]
.IP "\(bu" 4
A lost warning \*(L"Can't declare ... dereference in my\*(R" has been
restored (Perl had it earlier but it became lost in later releases.)
.IP "\(bu" 4
A new special regular expression variable has been introduced:
\&\f(CW$^N\fR, which contains the most-recently closed group (submatch).
.IP "\(bu" 4
\&\f(CW\*(C`no Module;\*(C'\fR does not produce an error even if Module does not have an
\&\fIunimport()\fR method.  This parallels the behavior of \f(CW\*(C`use\*(C'\fR vis-a-vis
\&\f(CW\*(C`import\*(C'\fR. [561]
.IP "\(bu" 4
The numerical comparison operators return \f(CW\*(C`undef\*(C'\fR if either operand
is a NaN.  Previously the behaviour was unspecified.
.IP "\(bu" 4
\&\f(CW\*(C`our\*(C'\fR can now have an experimental optional attribute \f(CW\*(C`unique\*(C'\fR that
affects how global variables are shared among multiple interpreters,
see \*(L"our\*(R" in perlfunc.
.IP "\(bu" 4
The following builtin functions are now overridable: \fIeach()\fR, \fIkeys()\fR,
\&\fIpop()\fR, \fIpush()\fR, \fIshift()\fR, \fIsplice()\fR, \fIunshift()\fR. [561]
.IP "\(bu" 4
\&\f(CW\*(C`pack() / unpack()\*(C'\fR can now group template letters with \f(CW\*(C`()\*(C'\fR and then
apply repetition/count modifiers on the groups.
.IP "\(bu" 4
\&\f(CW\*(C`pack() / unpack()\*(C'\fR can now process the Perl internal numeric types:
IVs, UVs, NVs\*(-- and also long doubles, if supported by the platform.
The template letters are \f(CW\*(C`j\*(C'\fR, \f(CW\*(C`J\*(C'\fR, \f(CW\*(C`F\*(C'\fR, and \f(CW\*(C`D\*(C'\fR.
.IP "\(bu" 4
\&\f(CW\*(C`pack(\*(AqU0a*\*(Aq, ...)\*(C'\fR can now be used to force a string to \s-1UTF\-8\s0.
.IP "\(bu" 4
my _\|_PACKAGE_\|_ \f(CW$obj\fR now works. [561]
.IP "\(bu" 4
\&\fIPOSIX::sleep()\fR now returns the number of \fIunslept\fR seconds
(as the \s-1POSIX\s0 standard says), as opposed to \fICORE::sleep()\fR which
returns the number of slept seconds.
.IP "\(bu" 4
\&\fIprintf()\fR and \fIsprintf()\fR now support parameter reordering using the
\&\f(CW\*(C`%\ed+\e$\*(C'\fR and \f(CW\*(C`*\ed+\e$\*(C'\fR syntaxes.  For example
.Sp
.Vb 1
\&    printf "%2\e$s %1\e$s\en", "foo", "bar";
.Ve
.Sp
will print \*(L"bar foo\en\*(R".  This feature helps in writing
internationalised software, and in general when the order
of the parameters can vary.
.IP "\(bu" 4
The (\e&) prototype now works properly. [561]
.IP "\(bu" 4
prototype(\e[$@%&]) is now available to implicitly create references
(useful for example if you want to emulate the \fItie()\fR interface).
.IP "\(bu" 4
A new command-line option, \f(CW\*(C`\-t\*(C'\fR is available.  It is the
little brother of \f(CW\*(C`\-T\*(C'\fR: instead of dying on taint violations,
lexical warnings are given.  \fBThis is only meant as a temporary
debugging aid while securing the code of old legacy applications.
This is not a substitute for \-T.\fR
.IP "\(bu" 4
In other taint news, the \f(CW\*(C`exec LIST\*(C'\fR and \f(CW\*(C`system LIST\*(C'\fR have now been
considered too risky (think \f(CW\*(C`exec @ARGV\*(C'\fR: it can start any program
with any arguments), and now the said forms cause a warning under
lexical warnings.  You should carefully launder the arguments to
guarantee their validity.  In future releases of Perl the forms will
become fatal errors so consider starting laundering now.
.IP "\(bu" 4
Tied hash interfaces are now required to have the \s-1EXISTS\s0 and \s-1DELETE\s0
methods (either own or inherited).
.IP "\(bu" 4
If tr/// is just counting characters, it doesn't attempt to
modify its target.
.IP "\(bu" 4
\&\fIuntie()\fR will now call an \s-1\fIUNTIE\s0()\fR hook if it exists.  See perltie
for details. [561]
.IP "\(bu" 4
utime now supports \f(CW\*(C`utime undef, undef, @files\*(C'\fR to change the
file timestamps to the current time.
.IP "\(bu" 4
The rules for allowing underscores (underbars) in numeric constants
have been relaxed and simplified: now you can have an underscore
simply \fBbetween digits\fR.
.IP "\(bu" 4
Rather than relying on C's argv[0] (which may not contain a full pathname)
where possible $^X is now set by asking the operating system.
(eg by reading \fI/proc/self/exe\fR on Linux, \fI/proc/curproc/file\fR on FreeBSD)
.IP "\(bu" 4
A new variable, \f(CW\*(C`${^TAINT}\*(C'\fR, indicates whether taint mode is enabled.
.IP "\(bu" 4
You can now override the \fIreadline()\fR builtin, and this overrides also
the <\s-1FILEHANDLE\s0> angle bracket operator.
.IP "\(bu" 4
The command-line options \-s and \-F are now recognized on the shebang
(#!) line.
.IP "\(bu" 4
Use of the \f(CW\*(C`/c\*(C'\fR match modifier without an accompanying \f(CW\*(C`/g\*(C'\fR modifier
elicits a new warning: \f(CW\*(C`Use of /c modifier is meaningless without /g\*(C'\fR.
.Sp
Use of \f(CW\*(C`/c\*(C'\fR in substitutions, even with \f(CW\*(C`/g\*(C'\fR, elicits
\&\f(CW\*(C`Use of /c modifier is meaningless in s///\*(C'\fR.
.Sp
Use of \f(CW\*(C`/g\*(C'\fR with \f(CW\*(C`split\*(C'\fR elicits \f(CW\*(C`Use of /g modifier is meaningless
in split\*(C'\fR.
.IP "\(bu" 4
Support for the \f(CW\*(C`CLONE\*(C'\fR special subroutine had been added.
With ithreads, when a new thread is created, all Perl data is cloned,
however non-Perl data cannot be cloned automatically.  In \f(CW\*(C`CLONE\*(C'\fR you
can do whatever you need to do, like for example handle the cloning of
non-Perl data, if necessary.  \f(CW\*(C`CLONE\*(C'\fR will be executed once for every
package that has it defined or inherited.  It will be called in the
context of the new thread, so all modifications are made in the new area.
.Sp
See perlmod
.SH "Modules and Pragmata"
.IX Header "Modules and Pragmata"
.Sh "New Modules and Pragmata"
.IX Subsection "New Modules and Pragmata"
.IP "\(bu" 4
\&\f(CW\*(C`Attribute::Handlers\*(C'\fR, originally by Damian Conway and now maintained
by Arthur Bergman, allows a class to define attribute handlers.
.Sp
.Vb 3
\&    package MyPack;
\&    use Attribute::Handlers;
\&    sub Wolf :ATTR(SCALAR) { print "howl!\en" }
\&
\&    # later, in some package using or inheriting from MyPack...
\&
\&    my MyPack $Fluffy : Wolf; # the attribute handler Wolf will be called
.Ve
.Sp
Both variables and routines can have attribute handlers.  Handlers can
be specific to type (\s-1SCALAR\s0, \s-1ARRAY\s0, \s-1HASH\s0, or \s-1CODE\s0), or specific to the
exact compilation phase (\s-1BEGIN\s0, \s-1CHECK\s0, \s-1INIT\s0, or \s-1END\s0).
See Attribute::Handlers.
.IP "\(bu" 4
\&\f(CW\*(C`B::Concise\*(C'\fR, by Stephen McCamant, is a new compiler backend for
walking the Perl syntax tree, printing concise info about ops.
The output is highly customisable.  See B::Concise. [561+]
.IP "\(bu" 4
The new bignum, bigint, and bigrat pragmas, by Tels, implement
transparent bignum support (using the Math::BigInt, Math::BigFloat,
and Math::BigRat backends).
.IP "\(bu" 4
\&\f(CW\*(C`Class::ISA\*(C'\fR, by Sean Burke, is a module for reporting the search
path for a class's \s-1ISA\s0 tree.  See Class::ISA.
.IP "\(bu" 4
\&\f(CW\*(C`Cwd\*(C'\fR now has a split personality: if possible, an \s-1XS\s0 extension is
used, (this will hopefully be faster, more secure, and more robust)
but if not possible, the familiar Perl implementation is used.
.IP "\(bu" 4
\&\f(CW\*(C`Devel::PPPort\*(C'\fR, originally by Kenneth Albanowski and now
maintained by Paul Marquess, has been added.  It is primarily used
by \f(CW\*(C`h2xs\*(C'\fR to enhance portability of \s-1XS\s0 modules between different
versions of Perl.  See Devel::PPPort.
.IP "\(bu" 4
\&\f(CW\*(C`Digest\*(C'\fR, frontend module for calculating digests (checksums), from
Gisle Aas, has been added.  See Digest.
.IP "\(bu" 4
\&\f(CW\*(C`Digest::MD5\*(C'\fR for calculating \s-1MD5\s0 digests (checksums) as defined in
\&\s-1RFC\s0 1321, from Gisle Aas, has been added.  See Digest::MD5.
.Sp
.Vb 1
\&    use Digest::MD5 \*(Aqmd5_hex\*(Aq;
\&
\&    $digest = md5_hex("Thirsty Camel");
\&
\&    print $digest, "\en"; # 01d19d9d2045e005c3f1b80e8b164de1
.Ve
.Sp
\&\s-1NOTE:\s0 the \f(CW\*(C`MD5\*(C'\fR backward compatibility module is deliberately not
included since its further use is discouraged.
.Sp
See also PerlIO::via::QuotedPrint.
.IP "\(bu" 4
\&\f(CW\*(C`Encode\*(C'\fR, originally by Nick Ing-Simmons and now maintained by Dan
Kogai, provides a mechanism to translate between different character
encodings.  Support for Unicode, \s-1ISO\-8859\-1\s0, and \s-1ASCII\s0 are compiled in
to the module.  Several other encodings (like the rest of the
\&\s-1ISO\-8859\s0, CP*/Win*, Mac, \s-1KOI8\-R\s0, three variants \s-1EBCDIC\s0, Chinese,
Japanese, and Korean encodings) are included and can be loaded at
runtime.  (For space considerations, the largest Chinese encodings
have been separated into their own \s-1CPAN\s0 module, Encode::HanExtra,
which Encode will use if available).  See Encode.
.Sp
Any encoding supported by Encode module is also available to the
\&\*(L":\fIencoding()\fR\*(R" layer if PerlIO is used.
.IP "\(bu" 4
\&\f(CW\*(C`Hash::Util\*(C'\fR is the interface to the new \fIrestricted hashes\fR
feature.  (Implemented by Jeffrey Friedl, Nick Ing-Simmons, and
Michael Schwern.)  See Hash::Util.
.IP "\(bu" 4
\&\f(CW\*(C`I18N::Langinfo\*(C'\fR can be used to query locale information.
See I18N::Langinfo.
.IP "\(bu" 4
\&\f(CW\*(C`I18N::LangTags\*(C'\fR, by Sean Burke, has functions for dealing with
RFC3066\-style language tags.  See I18N::LangTags.
.IP "\(bu" 4
\&\f(CW\*(C`ExtUtils::Constant\*(C'\fR, by Nicholas Clark, is a new tool for extension
writers for generating \s-1XS\s0 code to import C header constants.
See ExtUtils::Constant.
.IP "\(bu" 4
\&\f(CW\*(C`Filter::Simple\*(C'\fR, by Damian Conway, is an easy-to-use frontend to
Filter::Util::Call.  See Filter::Simple.
.Sp
.Vb 1
\&    # in MyFilter.pm:
\&
\&    package MyFilter;
\&
\&    use Filter::Simple sub {
\&        while (my ($from, $to) = splice @_, 0, 2) {
\&                s/$from/$to/g;
\&        }
\&    };
\&
\&    1;
\&
\&    # in user\*(Aqs code:
\&
\&    use MyFilter qr/red/ => \*(Aqgreen\*(Aq;
\&
\&    print "red\en";   # this code is filtered, will print "green\en"
\&    print "bored\en"; # this code is filtered, will print "bogreen\en"
\&
\&    no MyFilter;
\&
\&    print "red\en";   # this code is not filtered, will print "red\en"
.Ve
.IP "\(bu" 4
\&\f(CW\*(C`File::Temp\*(C'\fR, by Tim Jenness, allows one to create temporary files