Devil Killer Is Here MiNi Shell
MiNi SheLL

Current Path : /proc/thread-self/root/usr/local/man/man3/
Linux boscustweb5003.eigbox.net 5.4.91 #1 SMP Wed Jan 20 18:10:28 EST 2021 x86_64
Current File : //proc/thread-self/root/usr/local/man/man3/Attribute::Tie.3
.\" Automatically generated by Pod::Man v1.37, Pod::Parser v1.32
.\"
.\" 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.  | will give a
.\" real vertical bar.  \*(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-|\(bv\*(Tr
.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\}
.\"
.\" 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.
.if \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.\"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.hy 0
.if n .na
.\"
.\" 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 "Attribute::Tie 3"
.TH Attribute::Tie 3 "2006-12-22" "perl v5.8.8" "User Contributed Perl Documentation"
.SH "NAME"
Attribute::Tie \- Tie via Attribute
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 4
\&  use Attribute::Tie;
\&  my %hash   : Tie('Hash::Yours', args ...);
\&  my @array  : Tie('Array::Yours', args ...);
\&  my $scalar : Tie('Scalar::Yours', args ...);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Attribute::Tie allows you to tie variables via attribute.  This is
more intuitive than
.PP
.Vb 1
\&  tie my %hash, "Tie::Hash::Yours", args ... or die "$!";
.Ve
.PP
The first argument to \f(CW\*(C`Tie()\*(C'\fR is the name of the module to which you
want to tie the variable.  You can omit 'Tie' therein.
.PP
.Vb 2
\&  my %db  : Tie('DB_File', ....); # ties to DB_File;
\&  my @fie : Tie('File', ...);     # ties to Tie::File;
.Ve
.PP
You do not have to \f(CW\*(C`use Tie::Whatever\*(C'\fR; Attribute::Tie does it for you.
.Sh "Attribute::Tie vs Attribute::Handlers' autotie"
.IX Subsection "Attribute::Tie vs Attribute::Handlers' autotie"
I wrote this module for two reasons:
.IP "semantics" 2
.IX Item "semantics"
Attribute::Handlers offers an alternate approach via autotie.  That
looks like this.
.Sp
.Vb 2
\&  use Attribute::Handlers autotie => { File => 'Tie::File' };
\&  my @array : File('array.txt');
.Ve
.Sp
Which is handy but it hides the fact that the variable is actually
tied.  I want the attribute name to reflect what is really done to the
variable.
.IP "error handling" 2
.IX Item "error handling"
unlike most attributes, \f(CW\*(C`tie\*(C'\fR\-ing variable may fail.  This is
especially true for modules that tie variables to external files.  But
autotie does not trap the error; it just leaves the variable untied.
Consider this.
.Sp
.Vb 2
\&  use Attribute::Handlers autotie => { File => 'Tie::File' };
\&  my @array : File('/nonexistent/nowhere.txt');
.Ve
.Sp
Of course you can check the error like this.
.Sp
.Vb 1
\&  tied(@array) or die $!
.Ve
.Sp
or this:
.Sp
.Vb 1
\&  my @array : File('/nonexistent/nowhere.txt') or die $!;
.Ve
.Sp
First one is error-prone and the second one is unnatural because
setting attribute is not assignment.  When the error happens, it
should croak before the attribute is 'set', or fails to be set.
.Sp
On the other hand, Attribute::Tie dies on failure by default.
.Sp
.Vb 2
\&  my @array : Tie('File', '/nonexistent/nowhere.txt');
\&  # you die here!
.Ve
.Sh "\s-1CUSTOM\s0 \s-1ERROR\s0 \s-1HANDLER\s0"
.IX Subsection "CUSTOM ERROR HANDLER"
By default, Attribute::Tie dies on failure as follows.
.PP
.Vb 2
\&  tie(%HASH, 'SDBM_File', ./_none_/db, 514, 438) failed : 
\&  No such file or directory at t/04-error.t line 12
.Ve
.PP
You can change this behavior via \f(CW\*(C`Attribute::Tie\->seterror()\*(C'\fR.
.PP
.Vb 2
\&  # sets the error handler
\&  Attribute::Tie->seterror(sub{ die @_ });
.Ve
.PP
.Vb 2
\&  # disables error handling like Attribute::Handler's autotie
\&  Attribute::Tie->seterror(sub{});
.Ve
.PP
.Vb 3
\&   Attribute::Tie->seterror(0);
\&  # restores default handler
\&  Attribute::Tie->seterror(1);
.Ve
.Sh "\s-1EXPORT\s0"
.IX Subsection "EXPORT"
None by default.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
perltie, Attribute::Handlers
.SH "AUTHOR"
.IX Header "AUTHOR"
Dan Kogai, <dankogai@dan.co.jp>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
Copyright (C) 2006 by Dan Kogai
.PP
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.8 or,
at your option, any later version of Perl 5 you may have available.
Creat By MiNi SheLL
Email: devilkiller@gmail.com