perlembed.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.

.\" 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 "PERLEMBED 1"
.TH PERLEMBED 1 "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"
perlembed \- how to embed perl in your C program
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
.Sh "\s-1PREAMBLE\s0"
.IX Subsection "PREAMBLE"
Do you want to:
.IP "\fBUse C from Perl?\fR" 5
.IX Item "Use C from Perl?"
Read perlxstut, perlxs, h2xs, perlguts, and perlapi.
.IP "\fBUse a Unix program from Perl?\fR" 5
.IX Item "Use a Unix program from Perl?"
Read about back-quotes and about \f(CW\*(C`system\*(C'\fR and \f(CW\*(C`exec\*(C'\fR in perlfunc.
.IP "\fBUse Perl from Perl?\fR" 5
.IX Item "Use Perl from Perl?"
Read about \*(L"do\*(R" in perlfunc and \*(L"eval\*(R" in perlfunc and \*(L"require\*(R" in perlfunc 
and \*(L"use\*(R" in perlfunc.
.IP "\fBUse C from C?\fR" 5
.IX Item "Use C from C?"
Rethink your design.
.IP "\fBUse Perl from C?\fR" 5
.IX Item "Use Perl from C?"
Read on...
.Sh "\s-1ROADMAP\s0"
.IX Subsection "ROADMAP"
.IP "\(bu" 5
Compiling your C program
.IP "\(bu" 5
Adding a Perl interpreter to your C program
.IP "\(bu" 5
Calling a Perl subroutine from your C program
.IP "\(bu" 5
Evaluating a Perl statement from your C program
.IP "\(bu" 5
Performing Perl pattern matches and substitutions from your C program
.IP "\(bu" 5
Fiddling with the Perl stack from your C program
.IP "\(bu" 5
Maintaining a persistent interpreter
.IP "\(bu" 5
Maintaining multiple interpreter instances
.IP "\(bu" 5
Using Perl modules, which themselves use C libraries, from your C program
.IP "\(bu" 5
Embedding Perl under Win32
.Sh "Compiling your C program"
.IX Subsection "Compiling your C program"
If you have trouble compiling the scripts in this documentation,
you're not alone.  The cardinal rule: \s-1COMPILE\s0 \s-1THE\s0 \s-1PROGRAMS\s0 \s-1IN\s0 \s-1EXACTLY\s0
\&\s-1THE\s0 \s-1SAME\s0 \s-1WAY\s0 \s-1THAT\s0 \s-1YOUR\s0 \s-1PERL\s0 \s-1WAS\s0 \s-1COMPILED\s0.  (Sorry for yelling.)
.PP
Also, every C program that uses Perl must link in the \fIperl library\fR.
What's that, you ask?  Perl is itself written in C; the perl library
is the collection of compiled C programs that were used to create your
perl executable (\fI/usr/bin/perl\fR or equivalent).  (Corollary: you
can't use Perl from your C program unless Perl has been compiled on
your machine, or installed properly\*(--that's why you shouldn't blithely
copy Perl executables from machine to machine without also copying the
\&\fIlib\fR directory.)
.PP
When you use Perl from C, your C program will\*(--usually\-\-allocate,
\&\*(L"run\*(R", and deallocate a \fIPerlInterpreter\fR object, which is defined by
the perl library.
.PP
If your copy of Perl is recent enough to contain this documentation
(version 5.002 or later), then the perl library (and \fI\s-1EXTERN\s0.h\fR and
\&\fIperl.h\fR, which you'll also need) will reside in a directory
that looks like this:
.PP
.Vb 1
\&    /usr/local/lib/perl5/your_architecture_here/CORE
.Ve
.PP
or perhaps just
.PP
.Vb 1
\&    /usr/local/lib/perl5/CORE
.Ve
.PP
or maybe something like
.PP
.Vb 1
\&    /usr/opt/perl5/CORE
.Ve
.PP
Execute this statement for a hint about where to find \s-1CORE:\s0
.PP
.Vb 1
\&    perl \-MConfig \-e \*(Aqprint $Config{archlib}\*(Aq
.Ve
.PP
Here's how you'd compile the example in the next section,
\&\*(L"Adding a Perl interpreter to your C program\*(R", on my Linux box:
.PP
.Vb 4
\&    % gcc \-O2 \-Dbool=char \-DHAS_BOOL \-I/usr/local/include
\&    \-I/usr/local/lib/perl5/i586\-linux/5.003/CORE
\&    \-L/usr/local/lib/perl5/i586\-linux/5.003/CORE
\&    \-o interp interp.c \-lperl \-lm
.Ve
.PP
(That's all one line.)  On my \s-1DEC\s0 Alpha running old 5.003_05, the 
incantation is a bit different:
.PP
.Vb 4
\&    % cc \-O2 \-Olimit 2900 \-DSTANDARD_C \-I/usr/local/include
\&    \-I/usr/local/lib/perl5/alpha\-dec_osf/5.00305/CORE
\&    \-L/usr/local/lib/perl5/alpha\-dec_osf/5.00305/CORE \-L/usr/local/lib
\&    \-D_\|_LANGUAGE_C_\|_ \-D_NO_PROTO \-o interp interp.c \-lperl \-lm
.Ve
.PP
How can you figure out what to add?  Assuming your Perl is post\-5.001,
execute a \f(CW\*(C`perl \-V\*(C'\fR command and pay special attention to the \*(L"cc\*(R" and
\&\*(L"ccflags\*(R" information.
.PP
You'll have to choose the appropriate compiler (\fIcc\fR, \fIgcc\fR, et al.) for
your machine: \f(CW\*(C`perl \-MConfig \-e \*(Aqprint $Config{cc}\*(Aq\*(C'\fR will tell you what
to use.
.PP
You'll also have to choose the appropriate library directory
(\fI/usr/local/lib/...\fR) for your machine.  If your compiler complains
that certain functions are undefined, or that it can't locate
\&\fI\-lperl\fR, then you need to change the path following the \f(CW\*(C`\-L\*(C'\fR.  If it
complains that it can't find \fI\s-1EXTERN\s0.h\fR and \fIperl.h\fR, you need to
change the path following the \f(CW\*(C`\-I\*(C'\fR.
.PP
You may have to add extra libraries as well.  Which ones?
Perhaps those printed by
.PP
.Vb 1
\&   perl \-MConfig \-e \*(Aqprint $Config{libs}\*(Aq
.Ve
.PP
Provided your perl binary was properly configured and installed the
\&\fBExtUtils::Embed\fR module will determine all of this information for
you:
.PP
.Vb 1
\&   % cc \-o interp interp.c \`perl \-MExtUtils::Embed \-e ccopts \-e ldopts\`
.Ve
.PP
If the \fBExtUtils::Embed\fR module isn't part of your Perl distribution,
you can retrieve it from
http://www.perl.com/perl/CPAN/modules/by\-module/ExtUtils/
(If this documentation came from your Perl distribution, then you're
running 5.004 or better and you already have it.)
.PP
The \fBExtUtils::Embed\fR kit on \s-1CPAN\s0 also contains all source code for
the examples in this document, tests, additional examples and other
information you may find useful.
.Sh "Adding a Perl interpreter to your C program"
.IX Subsection "Adding a Perl interpreter to your C program"
In a sense, perl (the C program) is a good example of embedding Perl
(the language), so I'll demonstrate embedding with \fIminiperlmain.c\fR,
included in the source distribution.  Here's a bastardized, non-portable
version of \fIminiperlmain.c\fR containing the essentials of embedding:
.PP
.Vb 2
\&    #include <EXTERN.h>               /* from the Perl distribution     */
\&    #include <perl.h>                 /* from the Perl distribution     */
\&
\&    static PerlInterpreter *my_perl;  /***    The Perl interpreter    ***/
\&
\&    int main(int argc, char **argv, char **env)
\&    {
\&        PERL_SYS_INIT3(&argc,&argv,&env);
\&        my_perl = perl_alloc();
\&        perl_construct(my_perl);
\&        PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
\&        perl_parse(my_perl, NULL, argc, argv, (char **)NULL);
\&        perl_run(my_perl);
\&        perl_destruct(my_perl);
\&        perl_free(my_perl);
\&        PERL_SYS_TERM();
\&    }
.Ve
.PP
Notice that we don't use the \f(CW\*(C`env\*(C'\fR pointer.  Normally handed to
\&\f(CW\*(C`perl_parse\*(C'\fR as its final argument, \f(CW\*(C`env\*(C'\fR here is replaced by
\&\f(CW\*(C`NULL\*(C'\fR, which means that the current environment will be used.  The macros
\&\s-1\fIPERL_SYS_INIT3\s0()\fR and \s-1\fIPERL_SYS_TERM\s0()\fR provide system-specific tune up 
of the C runtime environment necessary to run Perl interpreters; since
\&\s-1\fIPERL_SYS_INIT3\s0()\fR may change \f(CW\*(C`env\*(C'\fR, it may be more appropriate to provide
\&\f(CW\*(C`env\*(C'\fR as an argument to \fIperl_parse()\fR.
.PP
Now compile this program (I'll call it \fIinterp.c\fR) into an executable:
.PP
.Vb 1
\&    % cc \-o interp interp.c \`perl \-MExtUtils::Embed \-e ccopts \-e ldopts\`
.Ve
.PP
After a successful compilation, you'll be able to use \fIinterp\fR just
like perl itself: