IO::Tee(3pm)

1IO::Tee(3)            User Contributed Perl Documentation           IO::Tee(3)
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NAME

6       IO::Tee - Multiplex output to multiple output handles
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SYNOPSIS

9           use IO::Tee;
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11           $tee = IO::Tee->new($handle1, $handle2);
12           print $tee "foo", "bar";
13           my $input = <$tee>;
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DESCRIPTION

16       "IO::Tee" objects can be used to multiplex input and output in two
17       different ways.  The first way is to multiplex output to zero or more
18       output handles.  The "IO::Tee" constructor, given a list of output
19       handles, returns a tied handle that can be written to.  When written to
20       (using print or printf), the "IO::Tee" object multiplexes the output to
21       the list of handles originally passed to the constructor.  As a
22       shortcut, you can also directly pass a string or an array reference to
23       the constructor, in which case "IO::File::new" is called for you with
24       the specified argument or arguments.
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26       The second way is to multiplex input from one input handle to zero or
27       more output handles as it is being read.  The "IO::Tee" constructor,
28       given an input handle followed by a list of output handles, returns a
29       tied handle that can be read from as well as written to.  When written
30       to, the "IO::Tee" object multiplexes the output to all handles passed
31       to the constructor, as described in the previous paragraph.  When read
32       from, the "IO::Tee" object reads from the input handle given as the
33       first argument to the "IO::Tee" constructor, then writes any data read
34       to the output handles given as the remaining arguments to the
35       constructor.
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37       The "IO::Tee" class supports certain "IO::Handle" and "IO::File"
38       methods related to input and output.  In particular, the following
39       methods will iterate themselves over all handles associated with the
40       "IO::Tee" object, and return TRUE indicating success if and only if all
41       associated handles returned TRUE indicating success:
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43       close
44       truncate
45       write
46       syswrite
47       format_write
48       formline
49       fcntl
50       ioctl
51       flush
52       clearerr
53       seek
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55       The following methods perform input multiplexing as described above:
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57       read
58       sysread
59       readline
60       getc
61       gets
62       eof
63       getline
64       getlines
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66       The following methods can be used to set (but not retrieve) the current
67       values of output-related state variables on all associated handles:
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69       autoflush
70       output_field_separator
71       output_record_separator
72       format_page_number
73       format_lines_per_page
74       format_lines_left
75       format_name
76       format_top_name
77       format_line_break_characters
78       format_formfeed
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80       The following methods are directly passed on to the input handle given
81       as the first argument to the "IO::Tee" constructor:
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83       input_record_separator
84       input_line_number
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86       Note that the return value of input multiplexing methods (such as
87       "print") is always the return value of the input action, not the return
88       value of subsequent output actions.  In particular, no error is
89       indicated by the return value if the input action itself succeeds but
90       subsequent output multiplexing fails.
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EXAMPLE

93           use IO::Tee;
94           use IO::File;
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96           my $tee = new IO::Tee(\*STDOUT,
97               new IO::File(">tt1.out"), ">tt2.out");
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99           print join(' ', $tee->handles), "\n";
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101           for (1..10) { print $tee $_, "\n" }
102           for (1..10) { $tee->print($_, "\n") }
103           $tee->flush;
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105           $tee = new IO::Tee('</etc/passwd', \*STDOUT);
106           my @lines = <$tee>;
107           print scalar(@lines);
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REPOSITORY

110       <https://github.com/neilb/IO-Tee>
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AUTHOR

113       Chung-chieh Shan, ken@digitas.harvard.edu
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115       As of August 2017, now being maintained by Neil Bowers.
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COPYRIGHT

118       Copyright (c) 1998-2017 Chung-chieh Shan.  All rights reserved.  This
119       program is free software; you can redistribute it and/or modify it
120       under the same terms as Perl itself.
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