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regcomp.c: Fix undefined behavior
[perl5.git] / lib / SelectSaver.pm
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1package SelectSaver;
2
11a12be6 3our $VERSION = '1.02';
b75c8c73 4
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5=head1 NAME
6
7SelectSaver - save and restore selected file handle
8
9=head1 SYNOPSIS
10
11 use SelectSaver;
12
13 {
2b393bf4 14 my $saver = SelectSaver->new(FILEHANDLE);
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15 # FILEHANDLE is selected
16 }
17 # previous handle is selected
18
19 {
2b393bf4 20 my $saver = SelectSaver->new;
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21 # new handle may be selected, or not
22 }
23 # previous handle is selected
24
25=head1 DESCRIPTION
26
27A C<SelectSaver> object contains a reference to the file handle that
28was selected when it was created. If its C<new> method gets an extra
29parameter, then that parameter is selected; otherwise, the selected
30file handle remains unchanged.
31
32When a C<SelectSaver> is destroyed, it re-selects the file handle
33that was selected when it was created.
34
35=cut
36
37require 5.000;
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38use Carp;
39use Symbol;
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40
41sub new {
11a12be6 42 @_ >= 1 && @_ <= 2 or croak 'usage: SelectSaver->new( [FILEHANDLE] )';
37ec1aec 43 my $fh = select;
a399f54a 44 my $self = bless \$fh, $_[0];
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45 select qualify($_[1], caller) if @_ > 1;
46 $self;
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47}
48
49sub DESTROY {
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50 my $self = $_[0];
51 select $$self;
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52}
53
541;