"IO::Capture::Stderr" - Capture all output sent to "STDERR"

       Pass any arguments to new() in a single array reference.

          IO::Capture::Stderr->new( {FORCE_CAPTURE_WARN => 1} );

   FORCE_CAPTURE_WARN
           Normally,  IO::Capture::Stderr  will  capture text from warn() function calls. This is because output
           from warn() is normally directed to STDERR.  If you wish to force  IO::Capture::Stderr  to  grab  the
           text  from  warn(),  set  FORCE_CAPTURE_WARN to a 1.  Then "IO::Capture::Stderr" will save the handle
           that $SIG{__WARN__} was set to, redirect it to itself on "start()", and then set $SIG{__WARN__}  back
           after "stop()" is called.

       Mark Reynolds reynolds@sgi.com

       Jon Morgan jmorgan@sgi.com

       Copyright (c) 2003, Mark Reynolds. All Rights Reserved.  This module is free software. It  may  be  used,
       redistributed and/or modified under the same terms as Perl itself.

perl v5.36.0                                       2022-10-13                           IO::Capture::Stderr(3pm)

       The module "IO::Capture::Stderr", is derived from the abstract class "IO::Capture".  See IO::Capture. The
       purpose of the module (as the name suggests) is to capture any output sent to "STDOUT".  After the
       capture is stopped, the STDOUT filehandle will be reset to the previous location. E.g., If previously
       redirected to a file, when "IO::Capture->stop" is called, output will start going into that file again.

       Note:  This module won't work with the perl function, system(), or any other operation
              involving a fork().  If you want to capture the output from a system command,
              it is faster to use open() or back-ticks.

              my $output = `/usr/sbin/ls -l 2>&1`;

new
       •   Creates a new capture object.

       •   An object can be reused as needed, so will only need to do one of these.

           •   Be aware, any data previously captured will be discarded if a new capture session is started.

   start
       •   Start capturing data into the "IO::Capture" Object.

       •   Can not be called on an object that is already capturing.

       •   Can not be called while STDERR tied to an object.

       •   "undef" will be returned on an error.

   stop
       •   Stop capturing data and point STDERR back to it's previous output location I.e., untie STDERR

   read
       •   In ScalarContext

           •   Lines  are  read  from  the  buffer  at  the  position  of the "line_pointer", and the pointer is
               incremented by one.

                   $next_line = $capture->read;

       •   In ListContext

           •   The array is returned.  The "line_pointer" is not affected.

                   @buffer = $capture->read;

       •   Data lines are returned exactly as they were captured.  You may want to use "chomp" on  them  if  you
           don't want the end of line character(s)

               while (my $line = $capture->read) {
                   chomp $line;
                   $cat_line = join '', $cat_line, $line;
               }

   line_pointer
       •   Reads or sets the "line_pointer".

               my $current_line = $capture->line_pointer;
               $capture->line_pointer(1);

       "IO::Capture::Stderr" - Capture all output sent to "STDERR"

       IO::Capture::Overview

       IO::Capture

       IO::Capture::Stdout

AddingFeatures
       If  you  would  like  to sub-class this module to add a feature (method) or two, here is a couple of easy
       steps. Also see IO::Capture::Overview.

       1.  Give your package a name

               package MyPackage;

       2.  Use this "IO::Capture::Stderr" as your base class like this:

               package MyPackage;

               use base qw/IO::Capture::Stderr/;

       3.  Add your new method like this

               package MyPackage;

               use base qw/IO::Capture::Stderr/;

               sub grep {
                   my $self = shift;

                   for $line (
               }

           use IO::Capture::Stderr;

           $capture = IO::Capture::Stderr->new();

           $capture->start();          # STDERR Output captured
           print STDERR "Test Line One\n";
           print STDERR "Test Line Two\n";
           print STDERR "Test Line Three\n";
           $capture->stop();           # STDERR output sent to wherever it was before 'start'

           # In 'scalar context' returns next line
           $line = $capture->read;
           print "$line";         # prints "Test Line One"

           $line = $capture->read;
           print "$line";         # prints "Test Line Two"

           # move line pointer to line 1
           $capture->line_pointer(1);

           $line = $capture->read;
           print "$line";         # prints "Test Line One"

           # Find out current line number
           $current_line_position = $capture->line_pointer;

           # In 'List Context' return an array(list)
           @all_lines = $capture->read;

           # Example 1 - "Using in module tests"
           #  Note: If you don't want to make users install
           #        the IO::Capture module just for your tests,
           #        you can just install in the t/lib directory
           #        of your module and use the lib pragma in
           #        your tests.

           use lib "t/lib";
           use IO::Capture:Stderr;

           use Test::More;

               # Create new capture object.  Showing FORCE_CAPTURE_WARN being cleared
               # for example, but 0 is the default, so you don't need to specify
               # unless you want to set.
           my $capture =  IO::Capture:Stderr->new( {FORCE_CAPTURE_WARN => 0} );
           $capture->start

           # execute with a bad parameter to make sure get
           # an error.

           ok( ! $test("Bad Parameter") );

           $capture->stop();