#!/usr/bin/perl
use warnings;
use strict;
use threads;
use threads::shared;
use Tk;

my %shash;
#share(%shash); #will work only for first level keys
my %hash;

 share ($shash{'go'});
 share ($shash{'fileno'});
 share ($shash{'pid'});
 share ($shash{'die'});
 
 $shash{'go'} = 0;
 $shash{'fileno'} = -1;
 $shash{'pid'} = -1;
 $shash{'die'} = 0;

 $hash{'thread'} = threads->new(\&work);

my $mw = MainWindow->new(-background => 'gray50');

my $text = $mw->Scrolled('Text')->pack();


my $startb = $mw->Button( -text => 'Start',
                -command=>sub{
                     $shash{'go'} = 1;
		     $mw->after(100); #give pipe chance to startup
		     my $fileno = $shash{'fileno'};
                     print "fileno_m $fileno\n";
		  open (my $fh, "<&=$fileno") or warn "$!\n";

 # filevent works but may not work on win32, 
 # but you can use a timer instead as shown below
 $mw->fileevent(\*$fh, 'readable', );             
             while(<$fh>){
	        $text->insert('end',$_);	
                $text->see('end');	              
                $mw->update;
	       }

# on Win32 (untested by me) you will need 
# a timer instead of fileevent

#   my $repeater; 
#        $repeater = $mw->repeat(10,
#          sub {
#              my $bytes = sysread( "<&=$fileno", my $buf, 8192);
#	      $text->insert('end',$buf);	
#                     $text->see('end'); 		
#	      if( $shash{'go'} == 0 ){ $repeater->cancel }
#			   }
#			 );     		
		
             }
                 )->pack();

my $stopb = $mw->Button( -text => 'Stop/Exit',
                -command=>sub{
		         $shash{'die'} = 1;
		         kill 9,$shash{'pid'};
		         $hash{'thread'}->join;         
		         exit;
		      },
                 )->pack();


MainLoop;

##################################################################
sub work{
    $|++; 
    while(1){
       if($shash{'die'} == 1){ return }; 
      
       if ( $shash{'go'} == 1 ){

        #run your command here, and try to find a way to capture it's output
        # on win32 you may need to use IPC::Run in the thread
        
        #use a win32 command that gives continous output
        # on linux I use top
        my $pid = open(FH, "top -b |" ) or warn "$!\n";


        my $fileno = fileno(FH);
        print "fileno_t->$fileno\n";
        $shash{'fileno'} = $fileno;
        $shash{'pid'} = $pid;
       
    $shash{'go'} = 0; #turn off self before returning      
       }else
         { select(undef,undef,undef,.1) } #short sleep
    }

}
#####################################################################