lib.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.

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.\" ========================================================================
.\"
.IX Title "lib 3"
.TH lib 3 "2008-01-23" "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"
lib \- manipulate @INC at compile time
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    use lib LIST;
\&
\&    no lib LIST;
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This is a small simple module which simplifies the manipulation of \f(CW@INC\fR
at compile time.
.PP
It is typically used to add extra directories to perl's search path so
that later \f(CW\*(C`use\*(C'\fR or \f(CW\*(C`require\*(C'\fR statements will find modules which are
not located on perl's default search path.
.ie n .Sh "Adding directories to @INC"
.el .Sh "Adding directories to \f(CW@INC\fP"
.IX Subsection "Adding directories to @INC"
The parameters to \f(CW\*(C`use lib\*(C'\fR are added to the start of the perl search
path. Saying
.PP
.Vb 1
\&    use lib LIST;
.Ve
.PP
is \fIalmost\fR the same as saying
.PP
.Vb 1
\&    BEGIN { unshift(@INC, LIST) }
.Ve
.PP
For each directory in \s-1LIST\s0 (called \f(CW$dir\fR here) the lib module also
checks to see if a directory called \f(CW$dir\fR/$archname/auto exists.
If so the \f(CW$dir\fR/$archname directory is assumed to be a corresponding
architecture specific directory and is added to \f(CW@INC\fR in front of \f(CW$dir\fR.
.PP
The current value of \f(CW$archname\fR can be found with this command:
.PP
.Vb 1
\&    perl \-V:archname
.Ve
.PP
To avoid memory leaks, all trailing duplicate entries in \f(CW@INC\fR are
removed.
.ie n .Sh "Deleting directories from @INC"
.el .Sh "Deleting directories from \f(CW@INC\fP"
.IX Subsection "Deleting directories from @INC"
You should normally only add directories to \f(CW@INC\fR.  If you need to
delete directories from \f(CW@INC\fR take care to only delete those which you
added yourself or which you are certain are not needed by other modules
in your script.  Other modules may have added directories which they
need for correct operation.
.PP
The \f(CW\*(C`no lib\*(C'\fR statement deletes all instances of each named directory
from \f(CW@INC\fR.
.PP
For each directory in \s-1LIST\s0 (called \f(CW$dir\fR here) the lib module also
checks to see if a directory called \f(CW$dir\fR/$archname/auto exists.
If so the \f(CW$dir\fR/$archname directory is assumed to be a corresponding
architecture specific directory and is also deleted from \f(CW@INC\fR.
.ie n .Sh "Restoring original @INC"
.el .Sh "Restoring original \f(CW@INC\fP"
.IX Subsection "Restoring original @INC"
When the lib module is first loaded it records the current value of \f(CW@INC\fR
in an array \f(CW@lib::ORIG_INC\fR. To restore \f(CW@INC\fR to that value you
can say
.PP
.Vb 1
\&    @INC = @lib::ORIG_INC;
.Ve
.SH "CAVEATS"
.IX Header "CAVEATS"
In order to keep lib.pm small and simple, it only works with Unix
filepaths.  This doesn't mean it only works on Unix, but non-Unix
users must first translate their file paths to Unix conventions.
.PP
.Vb 3
\&    # VMS users wanting to put [.stuff.moo] into 
\&    # their @INC would write
\&    use lib \*(Aqstuff/moo\*(Aq;
.Ve
.SH "NOTES"
.IX Header "NOTES"
In the future, this module will likely use File::Spec for determining
paths, as it does now for Mac \s-1OS\s0 (where Unix-style or Mac-style paths
work, and Unix-style paths are converted properly to Mac-style paths
before being added to \f(CW@INC\fR).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
FindBin \- optional module which deals with paths relative to the source file.
.SH "AUTHOR"
.IX Header "AUTHOR"
Tim Bunce, 2nd June 1995.