perlport.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.

.Ve
.PP
A MacPerl script saved as a \*(L"droplet\*(R" will populate \f(CW@ARGV\fR with the full
pathnames of the files dropped onto the script.
.PP
Mac users can run programs under a type of command line interface
under \s-1MPW\s0 (Macintosh Programmer's Workshop, a free development
environment from Apple).  MacPerl was first introduced as an \s-1MPW\s0
tool, and \s-1MPW\s0 can be used like a shell:
.PP
.Vb 1
\&    perl myscript.plx some arguments
.Ve
.PP
ToolServer is another app from Apple that provides access to \s-1MPW\s0 tools
from \s-1MPW\s0 and the MacPerl app, which allows MacPerl programs to use
\&\f(CW\*(C`system\*(C'\fR, backticks, and piped \f(CW\*(C`open\*(C'\fR.
.PP
\&\*(L"Mac\ \s-1OS\s0\*(R" is the proper name for the operating system, but the value
in \f(CW$^O\fR is \*(L"MacOS\*(R".  To determine architecture, version, or whether
the application or \s-1MPW\s0 tool version is running, check:
.PP
.Vb 5
\&    $is_app    = $MacPerl::Version =~ /App/;
\&    $is_tool   = $MacPerl::Version =~ /MPW/;
\&    ($version) = $MacPerl::Version =~ /^(\eS+)/;
\&    $is_ppc    = $MacPerl::Architecture eq \*(AqMacPPC\*(Aq;
\&    $is_68k    = $MacPerl::Architecture eq \*(AqMac68K\*(Aq;
.Ve
.PP
Mac\ \s-1OS\s0\ X, based on NeXT's OpenStep \s-1OS\s0, runs MacPerl natively, under the
\&\*(L"Classic\*(R" environment.  There is no \*(L"Carbon\*(R" version of MacPerl to run
under the primary Mac \s-1OS\s0 X environment.  Mac\ \s-1OS\s0\ X and its Open Source
version, Darwin, both run Unix perl natively.
.PP
Also see:
.IP "\(bu" 4
MacPerl Development, http://dev.macperl.org/ .
.IP "\(bu" 4
The MacPerl Pages, http://www.macperl.com/ .
.IP "\(bu" 4
The MacPerl mailing lists, http://lists.perl.org/ .
.IP "\(bu" 4
\&\s-1MPW\s0, ftp://ftp.apple.com/developer/Tool_Chest/Core_Mac_OS_Tools/
.Sh "\s-1VMS\s0"
.IX Subsection "VMS"
Perl on \s-1VMS\s0 is discussed in perlvms in the perl distribution.
.PP
The official name of \s-1VMS\s0 as of this writing is OpenVMS.
.PP
Perl on \s-1VMS\s0 can accept either \s-1VMS\-\s0 or Unix-style file
specifications as in either of the following:
.PP
.Vb 2
\&    $ perl \-ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
\&    $ perl \-ne "print if /perl_setup/i" /sys$login/login.com
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.PP
but not a mixture of both as in:
.PP
.Vb 2
\&    $ perl \-ne "print if /perl_setup/i" sys$login:/login.com
\&    Can\*(Aqt open sys$login:/login.com: file specification syntax error
.Ve
.PP
Interacting with Perl from the Digital Command Language (\s-1DCL\s0) shell
often requires a different set of quotation marks than Unix shells do.
For example:
.PP
.Vb 2
\&    $ perl \-e "print ""Hello, world.\en"""
\&    Hello, world.
.Ve
.PP
There are several ways to wrap your perl scripts in \s-1DCL\s0 \fI.COM\fR files, if
you are so inclined.  For example:
.PP
.Vb 6
\&    $ write sys$output "Hello from DCL!"
\&    $ if p1 .eqs. ""
\&    $ then perl \-x \*(Aqf$environment("PROCEDURE")
\&    $ else perl \-x \- \*(Aqp1 \*(Aqp2 \*(Aqp3 \*(Aqp4 \*(Aqp5 \*(Aqp6 \*(Aqp7 \*(Aqp8
\&    $ deck/dollars="_\|_END_\|_"
\&    #!/usr/bin/perl
\&
\&    print "Hello from Perl!\en";
\&
\&    _\|_END_\|_
\&    $ endif
.Ve
.PP
Do take care with \f(CW\*(C`$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT\*(C'\fR if your
perl-in-DCL script expects to do things like \f(CW\*(C`$read = <STDIN>;\*(C'\fR.
.PP
The \s-1VMS\s0 operating system has two filesystems, known as \s-1ODS\-2\s0 and \s-1ODS\-5\s0.
.PP
For \s-1ODS\-2\s0, filenames are in the format \*(L"name.extension;version\*(R".  The
maximum length for filenames is 39 characters, and the maximum length for
extensions is also 39 characters.  Version is a number from 1 to
32767.  Valid characters are \f(CW\*(C`/[A\-Z0\-9$_\-]/\*(C'\fR.
.PP
The \s-1ODS\-2\s0 filesystem is case-insensitive and does not preserve case.
Perl simulates this by converting all filenames to lowercase internally.
.PP
For \s-1ODS\-5\s0, filenames may have almost any character in them and can include
Unicode characters.  Characters that could be misinterpreted by the \s-1DCL\s0
shell or file parsing utilities need to be prefixed with the \f(CW\*(C`^\*(C'\fR
character, or replaced with hexadecimal characters prefixed with the
\&\f(CW\*(C`^\*(C'\fR character.  Such prefixing is only needed with the pathnames are
in \s-1VMS\s0 format in applications.  Programs that can accept the \s-1UNIX\s0 format
of pathnames do not need the escape characters.  The maximum length for
filenames is 255 characters.  The \s-1ODS\-5\s0 file system can handle both
a case preserved and a case sensitive mode.
.PP
\&\s-1ODS\-5\s0 is only available on the OpenVMS for 64 bit platforms.
.PP
Support for the extended file specifications is being done as optional
settings to preserve backward compatibility with Perl scripts that
assume the previous \s-1VMS\s0 limitations.
.PP
In general routines on \s-1VMS\s0 that get a \s-1UNIX\s0 format file specification
should return it in a \s-1UNIX\s0 format, and when they get a \s-1VMS\s0 format
specification they should return a \s-1VMS\s0 format unless they are documented
to do a conversion.
.PP
For routines that generate return a file specification, \s-1VMS\s0 allows setting
if the C library which Perl is built on if it will be returned in \s-1VMS\s0
format or in \s-1UNIX\s0 format.
.PP
With the \s-1ODS\-2\s0 file system, there is not much difference in syntax of
filenames without paths for \s-1VMS\s0 or \s-1UNIX\s0.  With the extended character
set available with \s-1ODS\-5\s0 there can be a significant difference.
.PP
Because of this, existing Perl scripts written for \s-1VMS\s0 were sometimes
treating \s-1VMS\s0 and \s-1UNIX\s0 filenames interchangeably.  Without the extended
character set enabled, this behavior will mostly be maintained for
backwards compatibility.
.PP
When extended characters are enabled with \s-1ODS\-5\s0, the handling of
\&\s-1UNIX\s0 formatted file specifications is to that of a \s-1UNIX\s0 system.
.PP
\&\s-1VMS\s0 file specifications without extensions have a trailing dot.  An
equivalent \s-1UNIX\s0 file specification should not show the trailing dot.
.PP
The result of all of this, is that for \s-1VMS\s0, for portable scripts, you
can not depend on Perl to present the filenames in lowercase, to be
case sensitive, and that the filenames could be returned in either
\&\s-1UNIX\s0 or \s-1VMS\s0 format.
.PP
And if a routine returns a file specification, unless it is intended to
convert it, it should return it in the same format as it found it.
.PP
\&\f(CW\*(C`readdir\*(C'\fR by default has traditionally returned lowercased filenames.
When the \s-1ODS\-5\s0 support is enabled, it will return the exact case of the
filename on the disk.
.PP
Files without extensions have a trailing period on them, so doing a
\&\f(CW\*(C`readdir\*(C'\fR in the default mode with a file named \fIA.;5\fR will
return \fIa.\fR when \s-1VMS\s0 is (though that file could be opened with
\&\f(CW\*(C`open(FH, \*(AqA\*(Aq)\*(C'\fR).
.PP
With support for extended file specifications and if \f(CW\*(C`opendir\*(C'\fR was
given a \s-1UNIX\s0 format directory, a file named \fIA.;5\fR will return \fIa\fR
and optionally in the exact case on the disk.  When \f(CW\*(C`opendir\*(C'\fR is given
a \s-1VMS\s0 format directory, then \f(CW\*(C`readdir\*(C'\fR should return \fIa.\fR, and
again with the optionally the exact case.
.PP
\&\s-1RMS\s0 had an eight level limit on directory depths from any rooted logical
(allowing 16 levels overall) prior to \s-1VMS\s0 7.2, and even with versions of
\&\s-1VMS\s0 on \s-1VAX\s0 up through 7.3.  Hence \f(CW\*(C`PERL_ROOT:[LIB.2.3.4.5.6.7.8]\*(C'\fR is a
valid directory specification but \f(CW\*(C`PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]\*(C'\fR is
not.  \fIMakefile.PL\fR authors might have to take this into account, but at
least they can refer to the former as \f(CW\*(C`/PERL_ROOT/lib/2/3/4/5/6/7/8/\*(C'\fR.
.PP
Pumpkings and module integrators can easily see whether files with too many
directory levels have snuck into the core by running the following in the
top-level source directory:
.PP
.Vb 1
\&   $ perl \-ne "$_=~s/\es+.*//; print if scalar(split /\e//) > 8;" < MANIFEST
.Ve
.PP
The VMS::Filespec module, which gets installed as part of the build
process on \s-1VMS\s0, is a pure Perl module that can easily be installed on
non-VMS platforms and can be helpful for conversions to and from \s-1RMS\s0
native formats.  It is also now the only way that you should check to
see if \s-1VMS\s0 is in a case sensitive mode.
.PP
What \f(CW\*(C`\en\*(C'\fR represents depends on the type of file opened.  It usually
represents \f(CW\*(C`\e012\*(C'\fR but it could also be \f(CW\*(C`\e015\*(C'\fR, \f(CW\*(C`\e012\*(C'\fR, \f(CW\*(C`\e015\e012\*(C'\fR, 
\&\f(CW\*(C`\e000\*(C'\fR, \f(CW\*(C`\e040\*(C'\fR, or nothing depending on the file organization and 
record format.  The VMS::Stdio module provides access to the 
special \fIfopen()\fR requirements of files with unusual attributes on \s-1VMS\s0.
.PP
\&\s-1TCP/IP\s0 stacks are optional on \s-1VMS\s0, so socket routines might not be
implemented.  \s-1UDP\s0 sockets may not be supported.
.PP
The \s-1TCP/IP\s0 library support for all current versions of \s-1VMS\s0 is dynamically
loaded if present, so even if the routines are configured, they may
return a status indicating that they are not implemented.
.PP
The value of \f(CW$^O\fR on OpenVMS is \*(L"\s-1VMS\s0\*(R".  To determine the architecture
that you are running on without resorting to loading all of \f(CW%Config\fR
you can examine the content of the \f(CW@INC\fR array like so:
.PP
.Vb 2
\&    if (grep(/VMS_AXP/, @INC)) {
\&        print "I\*(Aqm on Alpha!\en";
\&
\&    } elsif (grep(/VMS_VAX/, @INC)) {
\&        print "I\*(Aqm on VAX!\en";
\&
\&    } elsif (grep(/VMS_IA64/, @INC)) {
\&        print "I\*(Aqm on IA64!\en";
\&
\&    } else {
\&        print "I\*(Aqm not so sure about where $^O is...\en";
\&    }
.Ve
.PP
In general, the significant differences should only be if Perl is running
on \s-1VMS_VAX\s0 or one of the 64 bit OpenVMS platforms.
.PP
On \s-1VMS\s0, perl determines the \s-1UTC\s0 offset from the \f(CW\*(C`SYS$TIMEZONE_DIFFERENTIAL\*(C'\fR
logical name.  Although the \s-1VMS\s0 epoch began at 17\-NOV\-1858 00:00:00.00,
calls to \f(CW\*(C`localtime\*(C'\fR are adjusted to count offsets from
01\-JAN\-1970 00:00:00.00, just like Unix.
.PP
Also see:
.IP "\(bu" 4
\&\fI\s-1README\s0.vms\fR (installed as README_vms), perlvms
.IP "\(bu" 4
vmsperl list, vmsperl\[e-mail]
.IP "\(bu" 4
vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
.Sh "\s-1VOS\s0"
.IX Subsection "VOS"
Perl on \s-1VOS\s0 is discussed in \fI\s-1README\s0.vos\fR in the perl distribution
(installed as perlvos).  Perl on \s-1VOS\s0 can accept either \s-1VOS\-\s0 or
Unix-style file specifications as in either of the following:
.PP
.Vb 2
\&    C<< $ perl \-ne "print if /perl_setup/i" >system>notices >>
\&    C<< $ perl \-ne "print if /perl_setup/i" /system/notices >>
.Ve
.PP
or even a mixture of both as in:
.PP
.Vb 1
\&    C<< $ perl \-ne "print if /perl_setup/i" >system/notices >>
.Ve
.PP
Even though \s-1VOS\s0 allows the slash character to appear in object
names, because the \s-1VOS\s0 port of Perl interprets it as a pathname
delimiting character, \s-1VOS\s0 files, directories, or links whose names
contain a slash character cannot be processed.  Such files must be
renamed before they can be processed by Perl.  Note that \s-1VOS\s0 limits
file names to 32 or fewer characters.
.PP
The value of \f(CW$^O\fR on \s-1VOS\s0 is \*(L"\s-1VOS\s0\*(R".  To determine the architecture that
you are running on without resorting to loading all of \f(CW%Config\fR you
can examine the content of the \f(CW@INC\fR array like so:
.PP
.Vb 6
\&    if ($^O =~ /VOS/) {
\&        print "I\*(Aqm on a Stratus box!\en";
\&    } else {
\&        print "I\*(Aqm not on a Stratus box!\en";
\&        die;
\&    }
.Ve
.PP
Also see:
.IP "\(bu" 4
\&\fI\s-1README\s0.vos\fR (installed as perlvos)
.IP "\(bu" 4
The \s-1VOS\s0 mailing list.
.Sp
There is no specific mailing list for Perl on \s-1VOS\s0.  You can post
comments to the comp.sys.stratus newsgroup, or subscribe to the general
Stratus mailing list.  Send a letter with \