NAME

       IO::Interactive - Utilities for interactive I/O

VERSION

       This document describes IO::Interactive version 1.02

SYNOPSIS

           use IO::Interactive qw(is_interactive interactive busy);

           if ( is_interactive() ) {
               print "Running interactively\n";
           }

           # or...

           print {interactive} "Running interactively\n";

           $fh = busy {
               do_noninteractive_stuff();
           }

DESCRIPTION

       This module provides three utility subroutines that make it easier to develop interactive
       applications.

       The "ARGV" filehandle, the one that "<>" or an empty "readline()" uses, has various magic
       associated with it. It's not actually opened until you try to read from it. Checking "-t
       ARGV" before you've tried to read from it might give you the wrong answer.  Not only that,
       you might not read from "ARGV". If the value in @ARGV is the magic filename "-" (a
       convention to mean the standard filehandle for input or output), "ARGV" might actually be
       "STDIN".  You don't want to think about all of this. This module is discussed in Perl Best
       Practices on page 218. Also see the "ARGV" entry in perlvar and the "readline" entry in
       perlfunc.

       "is_interactive()"
           This subroutine returns true if *ARGV and the currently selected filehandle (usually
           *STDOUT) are connected to the terminal. The test is considerably more sophisticated
           than:

               -t *ARGV && -t *STDOUT

           as it takes into account the magic behaviour of *ARGV.

           You can also pass "is_interactive" a writable filehandle, in which case it requires
           that filehandle be connected to a terminal (instead of the currently selected).  The
           usual suspect here is *STDERR:

               if ( is_interactive(*STDERR) ) {
                   carp $warning;
               }

       "interactive()"
           This subroutine returns *STDOUT if "is_interactive" is true. If "is_interactive()" is
           false, "interactive" returns a filehandle that does not print.

           This makes it easy to create applications that print out only when the application is
           interactive:

               print {interactive} "Please enter a value: ";
               my $value = <>;

           You can also pass "interactive" a writable filehandle, in which case it writes to that
           filehandle if it is connected to a terminal (instead of writing to *STDOUT). Once
           again, the usual suspect is *STDERR:

               print {interactive(*STDERR)} $warning;

       "busy {...}"
           This subroutine takes a block as its single argument and executes that block.  Whilst
           the block is executed, *ARGV is temporarily replaced by a closed filehandle. That is,
           no input from *ARGV is possible in a "busy" block.  Furthermore, any attempts to send
           input into the "busy" block through *ARGV is intercepted and a warning message is
           printed to *STDERR.  The "busy" call returns a filehandle that contains the
           intercepted input.

           A "busy" block is therefore useful to prevent attempts at input when the program is
           busy at some non-interactive task.

DIAGNOSTICS

       Unknown subroutine (%s) requested
           This module only exports the three subroutines described above.  You asked for
           something else. Maybe you misspelled the subroutine you wanted.

CONFIGURATION AND ENVIRONMENT

       IO::Interactive requires no configuration files or environment variables.

DEPENDENCIES

       This module requires the "openhandle()" subroutine from the Scalar::Util module.

INCOMPATIBILITIES

       None reported.

BUGS AND LIMITATIONS

       No bugs have been reported.

       Please report any bugs or feature requests to Github
       <https://github.com/briandfoy/io-interactive/issues>.

SOURCE AVAILABILITY

       This code is in GitHub:

               https://github.com/briandfoy/io-interactive

AUTHOR

       Damian Conway  "<DCONWAY@cpan.org>"

       Currently maintained by brian d foy "<bdfoy@cpan.org>".

       1.01 patch DMUEY "dmuey@cpan.org"

LICENCE AND COPYRIGHT

       Copyright © 2005-2021, Damian Conway "<DCONWAY@cpan.org>". All rights reserved.

       This module is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

DISCLAIMER OF WARRANTY

       BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE,
       TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
       COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF
       ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
       WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO
       THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE
       DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

       IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT
       HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY
       THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL,
       INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
       SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR
       LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY
       OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
       SUCH DAMAGES.