phpman > perldoc > IO::Tee(3pm)

NAME
    IO::Tee - Multiplex output to multiple output handles

SYNOPSIS
        use IO::Tee;

        $tee = IO::Tee->new($handle1, $handle2);
        print $tee "foo", "bar";
        my $input = <$tee>;

DESCRIPTION
    "IO::Tee" objects can be used to multiplex input and output in two different ways. The first way
    is to multiplex output to zero or more output handles. The "IO::Tee" constructor, given a list
    of output handles, returns a tied handle that can be written to. When written to (using print or
    printf), the "IO::Tee" object multiplexes the output to the list of handles originally passed to
    the constructor. As a shortcut, you can also directly pass a string or an array reference to the
    constructor, in which case "IO::File::new" is called for you with the specified argument or
    arguments.

    The second way is to multiplex input from one input handle to zero or more output handles as it
    is being read. The "IO::Tee" constructor, given an input handle followed by a list of output
    handles, returns a tied handle that can be read from as well as written to. When written to, the
    "IO::Tee" object multiplexes the output to all handles passed to the constructor, as described
    in the previous paragraph. When read from, the "IO::Tee" object reads from the input handle
    given as the first argument to the "IO::Tee" constructor, then writes any data read to the
    output handles given as the remaining arguments to the constructor.

    The "IO::Tee" class supports certain "IO::Handle" and "IO::File" methods related to input and
    output. In particular, the following methods will iterate themselves over all handles associated
    with the "IO::Tee" object, and return TRUE indicating success if and only if all associated
    handles returned TRUE indicating success:

    close
    truncate
    write
    syswrite
    format_write
    formline
    fcntl
    ioctl
    flush
    clearerr
    seek

    The following methods perform input multiplexing as described above:

    read
    sysread
    readline
    getc
    gets
    eof
    getline
    getlines

    The following methods can be used to set (but not retrieve) the current values of output-related
    state variables on all associated handles:

    autoflush
    output_field_separator
    output_record_separator
    format_page_number
    format_lines_per_page
    format_lines_left
    format_name
    format_top_name
    format_line_break_characters
    format_formfeed

    The following methods are directly passed on to the input handle given as the first argument to
    the "IO::Tee" constructor:

    input_record_separator
    input_line_number

    Note that the return value of input multiplexing methods (such as "print") is always the return
    value of the input action, not the return value of subsequent output actions. In particular, no
    error is indicated by the return value if the input action itself succeeds but subsequent output
    multiplexing fails.

EXAMPLE
        use IO::Tee;
        use IO::File;

        my $tee = new IO::Tee(\*STDOUT,
            new IO::File(">tt1.out"), ">tt2.out");

        print join(' ', $tee->handles), "\n";

        for (1..10) { print $tee $_, "\n" }
        for (1..10) { $tee->print($_, "\n") }
        $tee->flush;

        $tee = new IO::Tee('</etc/passwd', \*STDOUT);
        my @lines = <$tee>;
        print scalar(@lines);

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

AUTHOR
    Chung-chieh Shan, ken AT digitas.edu

    As of August 2017, now being maintained by Neil Bowers.

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

SEE ALSO
    perlfunc, IO::Handle, IO::File.