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[perl5.git] / ext / IO / lib / IO / Seekable.pm
1 #
2
3 package IO::Seekable;
4
5 =head1 NAME
6
7 IO::Seekable - supply seek based methods for I/O objects
8
9 =head1 SYNOPSIS
10
11     use IO::Seekable;
12     package IO::Something;
13     @ISA = qw(IO::Seekable);
14
15 =head1 DESCRIPTION
16
17 C<IO::Seekable> does not have a constuctor of its own as is intended to
18 be inherited by other C<IO::Handle> based objects. It provides methods
19 which allow seeking of the file descriptors.
20
21 If the C functions fgetpos() and fsetpos() are available, then
22 C<IO::File::getpos> returns an opaque value that represents the
23 current position of the IO::File, and C<IO::File::setpos> uses
24 that value to return to a previously visited position.
25
26 See L<perlfunc> for complete descriptions of each of the following
27 supported C<IO::Seekable> methods, which are just front ends for the
28 corresponding built-in functions:
29
30     clearerr
31     seek
32     tell
33
34 =head1 SEE ALSO
35
36 L<perlfunc>, 
37 L<perlop/"I/O Operators">,
38 L<IO::Handle>
39 L<IO::File>
40
41 =head1 HISTORY
42
43 Derived from FileHandle.pm by Graham Barr E<lt>bodg@tiuk.ti.comE<gt>
44
45 =cut
46
47 require 5.000;
48 use Carp;
49 use strict;
50 use vars qw($VERSION @EXPORT @ISA);
51 use IO::Handle qw(SEEK_SET SEEK_CUR SEEK_END);
52 require Exporter;
53
54 @EXPORT = qw(SEEK_SET SEEK_CUR SEEK_END);
55 @ISA = qw(Exporter);
56
57 $VERSION = "1.06";
58
59 sub clearerr {
60     @_ == 1 or croak 'usage: $fh->clearerr()';
61     seek($_[0], 0, SEEK_CUR);
62 }
63
64 sub seek {
65     @_ == 3 or croak 'usage: $fh->seek(POS, WHENCE)';
66     seek($_[0], $_[1], $_[2]);
67 }
68
69 sub tell {
70     @_ == 1 or croak 'usage: $fh->tell()';
71     tell($_[0]);
72 }
73
74 1;