version.3

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.

.\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.ie \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.el \{\
.    de IX
..
.\}
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "version 3"
.TH version 3 "2007-12-18" "perl v5.10.0" "Perl Programmers Reference Guide"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
version \- Perl extension for Version Objects
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 5
\&  use version;
\&  $version = version\->new("12.2.1"); # must be quoted for Perl < 5.8.1
\&  print $version;               # v12.2.1
\&  print $version\->numify;       # 12.002001
\&  if ( $version gt "12.2" )     # true
\&
\&  $alphaver = version\->new("1.02_03"); # must be quoted!
\&  print $alphaver;              # 1.02_0300
\&  print $alphaver\->is_alpha();  # true
\&  
\&  $ver = qv("1.2.0");           # v1.2.0
\&
\&  $perlver = version\->new(5.005_03); # must not be quoted!
\&  print $perlver;               # 5.005030
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Overloaded version objects for all modern versions of Perl.  This module
implements all of the features of version objects which will be part
of Perl 5.10.0.
.Sh "\s-1BEST\s0 \s-1PRACTICES\s0"
.IX Subsection "BEST PRACTICES"
If you intend for your module to be used by different releases of Perl,
and/or for your \f(CW$VERSION\fR scalar to mean what you think it means, there 
are a few simple rules to follow:
.IP "\(bu" 4
Be consistent
.Sp
Whichever of the two types of version objects that you choose to employ, 
you should stick to either \*(L"Numeric Versions\*(R" or \*(L"Extended Versions\*(R"
and not mix them together.  While this is \fIpossible\fR, it is very 
confusing to the average user.
.Sp
If you intend to use \*(L"Extended Versions\*(R", you are strongly encouraged 
to use the \fIqv()\fR operator with a quoted term, e.g.:
.Sp
.Vb 1
\&  use version; our $VERSION = qv("1.2.3");
.Ve
.Sp
on a single line as above.
.Sp
At the very least, decide on which of the several ways to initialize 
your version objects you prefer and stick with it.  It is also best to 
be explicit about what value you intend to assign your version object 
and to not rely on hidden behavior of the parser.
.IP "\(bu" 4
Be careful
.Sp
If you are using Module::Build or ExtUtils::MakeMaker, so that you can
release your module to \s-1CPAN\s0, you have to recognize that neither of those
programs completely handles version objects natively (yet).  If you use
version objects with Module::Build, you should add an explicit dependency
to the release of version.pm in your Build.PL:
.Sp
.Vb 9
\&  my $builder = Module::Build\->new(
\&     ...
\&     requires => {
\&         ... ,
\&         \*(Aqversion\*(Aq    => 0.50,
\&         ...,
\&     },
\&     ...
\&  );
.Ve
.Sp
and it should Just Work(\s-1TM\s0).  Module::Build will [hopefully soon] 
include full support for version objects; there are no current plans 
to patch ExtUtils::MakeMaker to support version objects.
.Sh "Using modules that use version.pm"
.IX Subsection "Using modules that use version.pm"
As much as possible, the version.pm module remains compatible with all
current code.  However, if your module is using a module that has defined
\&\f(CW$VERSION\fR using the version class, there are a couple of things to be
aware of.  For purposes of discussion, we will assume that we have the
following module installed:
.PP
.Vb 4
\&  package Example;
\&  use version;  $VERSION = qv(\*(Aq1.2.2\*(Aq);
\&  ...module code here...
\&  1;
.Ve
.IP "Numeric versions always work" 4
.IX Item "Numeric versions always work"
Code of the form:
.Sp
.Vb 1
\&  use Example 1.002003;
.Ve
.Sp
will always work correctly.  The \f(CW\*(C`use\*(C'\fR will perform an automatic
\&\f(CW$VERSION\fR comparison using the floating point number given as the first
term after the module name (e.g. above 1.002.003).  In this case, the
installed module is too old for the requested line, so you would see an
error like:
.Sp
.Vb 1
\&  Example version 1.002003 (v1.2.3) required\-\-this is only version 1.002002 (v1.2.2)...
.Ve
.IP "Extended version work sometimes" 4
.IX Item "Extended version work sometimes"
With Perl >= 5.6.2, you can also use a line like this:
.Sp
.Vb 1
\&  use Example 1.2.3;
.Ve
.Sp
and it will again work (i.e. give the error message as above), even with
releases of Perl which do not normally support v\-strings (see \*(L"What about
v\-strings\*(R" below).  This has to do with that fact that \f(CW\*(C`use\*(C'\fR only checks
to see if the second term \fIlooks like a number\fR and passes that to the
replacement \s-1UNIVERSAL::VERSION\s0.  This is not true in Perl 5.005_04,
however, so you are \fBstrongly encouraged\fR to always use a numeric version
in your code, even for those versions of Perl which support the extended
version.
.Sh "What \s-1IS\s0 a version"
.IX Subsection "What IS a version"
For the purposes of this module, a version \*(L"number\*(R" is a sequence of
positive integer values separated by one or more decimal points and 
optionally a single underscore.  This corresponds to what Perl itself 
uses for a version, as well as extending the \*(L"version as number\*(R" that 
is discussed in the various editions of the Camel book.
.PP
There are actually two distinct kinds of version objects:
.IP "\(bu" 4
Numeric Versions
.Sp
Any initial parameter which \*(L"looks like a number\*(R", see Numeric
Versions.  This also covers versions with a single decimal point and
a single embedded underscore, see \*(L"Numeric Alpha Versions\*(R", even though